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94<h1 class="text-center">Annotated List of Command-line Options</h1>
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href="command-line-options.html#posterize">-posterize</a>  • <a class="text-nowrap" href="command-line-options.html#precision">-precision</a>  • <a class="text-nowrap" href="command-line-options.html#preview">-preview</a>  • <a class="text-nowrap" href="command-line-options.html#print">-print</a>  • <a class="text-nowrap" href="command-line-options.html#process">-process</a>  • <a class="text-nowrap" href="command-line-options.html#profile">-profile</a>  • <a class="text-nowrap" href="command-line-options.html#quality">-quality</a>  • <a class="text-nowrap" href="command-line-options.html#quantize">-quantize</a>  • <a class="text-nowrap" href="command-line-options.html#quiet">-quiet</a>  • <a class="text-nowrap" href="command-line-options.html#radial-blur">-radial-blur</a>  • <a class="text-nowrap" href="command-line-options.html#raise">-raise</a>  • <a class="text-nowrap" href="command-line-options.html#random-threshold">-random-threshold</a>  • <a class="text-nowrap" href="command-line-options.html#range-threshold">-range-threshold</a>  • <a class="text-nowrap" href="command-line-options.html#read-mask">-read-mask</a>  • <a class="text-nowrap" href="command-line-options.html#red-primary">-red-primary</a>  • <a class="text-nowrap" href="command-line-options.html#regard-warnings">-regard-warnings</a>  • <a class="text-nowrap" href="command-line-options.html#region">-region</a>  • <a class="text-nowrap" href="command-line-options.html#remap">-remap</a>  • <a class="text-nowrap" href="command-line-options.html#remote">-remote</a>  • <a class="text-nowrap" href="command-line-options.html#render">-render</a>  • <a class="text-nowrap" href="command-line-options.html#repage">-repage</a>  • <a class="text-nowrap" href="command-line-options.html#resample">-resample</a>  • <a class="text-nowrap" href="command-line-options.html#resize">-resize</a>  • <a class="text-nowrap" href="command-line-options.html#respect-parentheses">-respect-parentheses</a>  • <a class="text-nowrap" href="command-line-options.html#reverse">-reverse</a>  • <a class="text-nowrap" href="command-line-options.html#roll">-roll</a>  • <a class="text-nowrap" href="command-line-options.html#rotate">-rotate</a>  • <a class="text-nowrap" href="command-line-options.html#sample">-sample</a>  • <a class="text-nowrap" href="command-line-options.html#sampling-factor">-sampling-factor</a>  • <a class="text-nowrap" href="command-line-options.html#scale">-scale</a>  • <a class="text-nowrap" href="command-line-options.html#scene">-scene</a>  • <a class="text-nowrap" href="command-line-options.html#screen">-screen</a>  • <a class="text-nowrap" href="command-line-options.html#seed">-seed</a>  • <a class="text-nowrap" href="command-line-options.html#segment">-segment</a>  • <a class="text-nowrap" href="command-line-options.html#selective-blur">-selective-blur</a>  • <a class="text-nowrap" href="command-line-options.html#separate">-separate</a>  • <a class="text-nowrap" href="command-line-options.html#sepia-tone">-sepia-tone</a>  • <a class="text-nowrap" href="command-line-options.html#set">-set</a>  • <a class="text-nowrap" href="command-line-options.html#shade">-shade</a>  • <a class="text-nowrap" href="command-line-options.html#shadow">-shadow</a>  • <a class="text-nowrap" href="command-line-options.html#shared-memory">-shared-memory</a>  • <a class="text-nowrap" href="command-line-options.html#sharpen">-sharpen</a>  • <a class="text-nowrap" href="command-line-options.html#shave">-shave</a>  • <a class="text-nowrap" href="command-line-options.html#shear">-shear</a>  • <a class="text-nowrap" href="command-line-options.html#sigmoidal-contrast">-sigmoidal-contrast</a>  • <a class="text-nowrap" href="command-line-options.html#silent">-silent</a>  • <a class="text-nowrap" href="command-line-options.html#similarity-threshold">-similarity-threshold</a>  • <a class="text-nowrap" href="command-line-options.html#size">-size</a>  • <a class="text-nowrap" href="command-line-options.html#sketch">-sketch</a>  • <a class="text-nowrap" href="command-line-options.html#smush">-smush</a>  • <a class="text-nowrap" href="command-line-options.html#snaps">-snaps</a>  • <a class="text-nowrap" href="command-line-options.html#solarize">-solarize</a>  • <a class="text-nowrap" href="command-line-options.html#sort-pixels">-sort-pixels</a>  • <a class="text-nowrap" href="command-line-options.html#sparse-color">-sparse-color</a>  • <a class="text-nowrap" href="command-line-options.html#splice">-splice</a>  • <a class="text-nowrap" href="command-line-options.html#spread">-spread</a>  • <a class="text-nowrap" href="command-line-options.html#statistic">-statistic</a>  • <a class="text-nowrap" href="command-line-options.html#stegano">-stegano</a>  • <a class="text-nowrap" href="command-line-options.html#stereo">-stereo</a>  • <a class="text-nowrap" href="command-line-options.html#storage-type">-storage-type</a>  • <a class="text-nowrap" href="command-line-options.html#stretch">-stretch</a>  • <a class="text-nowrap" href="command-line-options.html#strip">-strip</a>  • <a class="text-nowrap" href="command-line-options.html#stroke">-stroke</a>  • <a class="text-nowrap" href="command-line-options.html#strokewidth">-strokewidth</a>  • <a class="text-nowrap" href="command-line-options.html#style">-style</a>  • <a class="text-nowrap" href="command-line-options.html#subimage-search">-subimage-search</a>  • <a class="text-nowrap" href="command-line-options.html#swap">-swap</a>  • <a class="text-nowrap" href="command-line-options.html#swirl">-swirl</a>  • <a class="text-nowrap" href="command-line-options.html#synchronize">-synchronize</a>  • <a class="text-nowrap" href="command-line-options.html#taint">-taint</a>  • <a class="text-nowrap" href="command-line-options.html#text-font">-text-font</a>  • <a class="text-nowrap" href="command-line-options.html#texture">-texture</a>  • <a class="text-nowrap" href="command-line-options.html#threshold">-threshold</a>  • <a class="text-nowrap" href="command-line-options.html#thumbnail">-thumbnail</a>  • <a class="text-nowrap" href="command-line-options.html#tile">-tile</a>  • <a class="text-nowrap" href="command-line-options.html#tile-offset">-tile-offset</a>  • <a class="text-nowrap" href="command-line-options.html#tint">-tint</a>  • <a class="text-nowrap" href="command-line-options.html#title">-title</a>  • <a class="text-nowrap" href="command-line-options.html#transform">-transform</a>  • <a class="text-nowrap" href="command-line-options.html#transparent">-transparent</a>  • <a class="text-nowrap" href="command-line-options.html#transparent-color">-transparent-color</a>  • <a class="text-nowrap" href="command-line-options.html#transpose">-transpose</a>  • <a class="text-nowrap" href="command-line-options.html#transverse">-transverse</a>  • <a class="text-nowrap" href="command-line-options.html#treedepth">-treedepth</a>  • <a class="text-nowrap" href="command-line-options.html#trim">-trim</a>  • <a class="text-nowrap" href="command-line-options.html#type">-type</a>  • <a class="text-nowrap" href="command-line-options.html#undercolor">-undercolor</a>  • <a class="text-nowrap" href="command-line-options.html#unique-colors">-unique-colors</a>  • <a class="text-nowrap" href="command-line-options.html#units">-units</a>  • <a class="text-nowrap" href="command-line-options.html#unsharp">-unsharp</a>  • <a class="text-nowrap" href="command-line-options.html#update">-update</a>  • <a class="text-nowrap" href="command-line-options.html#verbose">-verbose</a>  • <a class="text-nowrap" href="command-line-options.html#version">-version</a>  • <a class="text-nowrap" href="command-line-options.html#view">-view</a>  • <a class="text-nowrap" href="command-line-options.html#vignette">-vignette</a>  • <a class="text-nowrap" href="command-line-options.html#virtual-pixel">-virtual-pixel</a>  • <a class="text-nowrap" href="command-line-options.html#visual">-visual</a>  • <a class="text-nowrap" href="command-line-options.html#watermark">-watermark</a>  • <a class="text-nowrap" href="command-line-options.html#wave">-wave</a>  • <a class="text-nowrap" href="command-line-options.html#wavelet-denoise">-wavelet-denoise</a>  • <a class="text-nowrap" href="command-line-options.html#weight">-weight</a>  • <a class="text-nowrap" href="command-line-options.html#white-balance">-white-balance</a>  • <a class="text-nowrap" href="command-line-options.html#white-point">-white-point</a>  • <a class="text-nowrap" href="command-line-options.html#white-threshold">-white-threshold</a>  • <a class="text-nowrap" href="command-line-options.html#window">-window</a>  • <a class="text-nowrap" href="command-line-options.html#window-group">-window-group</a>  • <a class="text-nowrap" href="command-line-options.html#write">-write</a>  • <a class="text-nowrap" href="command-line-options.html#write-mask">-write-mask</a>  </p>
96<p class="lead magick-description">Below is list of command-line options recognized by the ImageMagick <a href="command-line-tools.html">command-line tools</a>. If you want a description of a particular option, click on the option name in the navigation bar above and you will go right to it. Unless otherwise noted, each option is recognized by the commands: <a href="../www/convert.html">convert</a> and <a href="mogrify.html">mogrify</a>.</p>
97
98<div style="margin: auto;">
99  <h3><a class="anchor" id="adaptive-blur"></a>-adaptive-blur <var>radius</var>[x<var>sigma</var>]</h3>
100</div>
101
102<p class="magick-description">Adaptively blur pixels, with decreasing effect near edges.</p>
103
104<p>A Gaussian operator of the given radius and standard deviation (<var>sigma</var>) is used. If <var>sigma</var> is not given it
105defaults to 1.</p>
106
107<div style="margin: auto;">
108  <h3><a class="anchor" id="adaptive-resize"></a>-adaptive-resize <var>geometry</var></h3>
109</div>
110
111<p class="magick-description">Resize the image using data-dependent triangulation.</p>
112
113<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. The <a href="command-line-options.html#adaptive-resize">-adaptive-resize</a>
114option defaults to data-dependent triangulation.  Use the <a
115href="command-line-options.html#filter">-filter</a> to choose a different resampling algorithm.
116Offsets, if present in the geometry string, are ignored, and the <a
117href="command-line-options.html#gravity">-gravity</a> option has no effect.</p>
118
119<div style="margin: auto;">
120  <h3><a class="anchor" id="adaptive-sharpen"></a>-adaptive-sharpen <var>radius</var>[x<var>sigma</var>]</h3>
121</div>
122
123<p class="magick-description">Adaptively sharpen pixels, with increasing effect near edges.</p>
124
125<p>A Gaussian operator of the given radius and standard deviation
126(<var>sigma</var>) is used. If <var>sigma</var> is not given it
127defaults to 1.</p>
128
129<div style="margin: auto;">
130  <h3><a class="anchor" id="adjoin"></a>-adjoin</h3>
131</div>
132
133<p class="magick-description">Join images into a single multi-image file.</p>
134
135<p>This option is enabled by default. An attempt is made to save all images of
136an image sequence into the given output file.  However, some formats, such as
137JPEG and PNG, do not support more than one image per file, and in that case
138ImageMagick is forced to write each image as a separate file.  As such, if
139more than one image needs to be written, the filename given is modified by
140adding a <a href="command-line-options.html#scene">-scene</a> number before the suffix, in order to
141make distinct names for each image. </p>
142
143<p>Use <a href="command-line-options.html#adjoin">+adjoin</a> to force each image to be written to
144separate files, whether or not the file format allows multiple images per file
145(for example, GIF, MIFF, and TIFF). </p>
146
147<p>Including a C-style integer format string in the output filename will
148automagically enable <a href="command-line-options.html#adjoin">+adjoin</a> and are used to specify
149where the <a href="command-line-options.html#scene">-scene</a> number is placed in the filenames. These
150strings, such as '<code>%d</code>' or '<code>%03d</code>', are familiar to those
151who have used the standard <code>printf()</code>' C-library function. As an
152example, the command</p>
153
154<pre class="highlight"><code>magick logo: rose: -morph 15 my%02dmorph.jpg
155</code></pre>
156
157<p>will create a sequence of 17 images (the two given plus 15 more created by
158<a href="command-line-options.html#morph">-morph</a>), named: my00morph.jpg, my01morph.jpg,
159my02morph.jpg, ..., my16morph.jpg.  </p>
160
161<p>In summary, ImageMagick tries to write all images to one file, but will
162save to multiple files, if any of the following conditions exist...</p>
163<ol>
164<li>the output image's file format does not allow multi-image files,</li>
165<li>the <a href="command-line-options.html#adjoin">+adjoin</a> option is given, or</li>
166<li>a printf() integer format string (eg: "%d") is present in the output
167 filename.</li>
168</ol>
169
170
171<div style="margin: auto;">
172  <h3><a class="anchor" id="affine"></a>-affine
173  <var>s<sub>x</sub></var>,<var>r<sub>x</sub></var>,<var>r<sub>y</sub></var>,<var>s<sub>y</sub></var>[,<var>t<sub>x</sub></var>,<var>t<sub>y</sub></var>]</h3>
174</div>
175
176<p class="magick-description">Set the drawing transformation matrix for combined rotating and scaling.</p>
177
178<p>This option sets a transformation matrix, for use by subsequent <a
179href="command-line-options.html#draw">-draw</a> or <a href="command-line-options.html#transform">-transform</a> options. </p>
180
181<p>The matrix entries are entered as comma-separated numeric values either in
182quotes or without spaces. </p>
183
184<p>Internally, the transformation matrix has 3x3 elements, but three of them
185are omitted from the input because they are constant. The new (transformed)
186coordinates (<var>x'</var>, <var>y'</var>) of a pixel at
187position (<var>x</var>, <var>y</var>) in the original
188image are calculated using the following matrix equation.</p>
189
190<p class="text-center"><img class="img-thumbnail" alt="affine transformation"  src="../images/affine.png"/> </p>
191
192<p> The size of the resulting image is that of the smallest rectangle that
193contains the transformed source image.  The parameters
194<var>t<sub>x</sub></var> and <var>t<sub>y</sub></var>
195subsequently shift the image pixels so that those that are moved out of the
196image area are cut off.</p>
197
198<p>The transformation matrix complies with the left-handed pixel coordinate
199system: positive <var>x</var> and <var>y</var> directions
200are rightward and downward, resp.; positive rotation is clockwise.</p>
201
202<p> If the translation coefficients <var>t<sub>x</sub></var> and
203<var>t<sub>y</sub></var> are omitted they default to 0,0. Therefore,
204four parameters suffice for rotation and scaling without translation.</p>
205
206<p>Scaling by the factors <var>s<sub>x</sub></var> and
207<var>s<sub>y</sub></var> in the <var>x</var> and <var>y</var> directions,
208respectively, is accomplished with the following.</p>
209
210<p>See <a href="command-line-options.html#transform">-transform</a>, and the <a
211href="command-line-options.html#distort">-distort</a> method '<code>Affineprojection</code> for more
212information </p>
213
214
215<pre class="highlight"><code>-affine <var>s<sub>x</sub></var>,0,0,<var>s<sub>y</sub></var>
216</code></pre>
217
218<p>Translation by a displacement (<var>t<sub>x</sub></var>, <var>t<sub>y</sub></var>) is accomplished like so:</p>
219
220<pre class="highlight"><code>-affine 1,0,0,1,<var>t<sub>x</sub></var>,<var>t<sub>y</sub></var>
221</code></pre>
222
223<p>Rotate clockwise about the origin (the upper left-hand corner) by an angle
224<var>a</var> by letting <var>c</var> = cos(<var>a</var>), <var>s</var>
225= sin(<var>a</var>), and using the following.</p>
226
227<pre class="highlight"><code>-affine <var>c</var>,<var>s</var>,-<var>s</var>,<var>c</var>
228</code></pre>
229
230<p>The cumulative effect of a sequence of <a href="command-line-options.html#affine" >-affine</a>
231transformations can be accomplished by instead by a single <a href="command-line-options.html#affine"
232>-affine</a> operation using the matrix equal to the product of the matrices
233of the individual transformations.</p>
234
235<p>An attempt is made to detect near-singular transformation matrices. If the
236matrix determinant has a sufficiently small absolute value it is rejected.</p>
237
238<div style="margin: auto;">
239  <h3><a class="anchor" id="alpha"></a>-alpha <var>type</var></h3>
240</div>
241
242<p class="magick-description">Gives control of the alpha/matte channel of an image.</p>
243
244<p>Used to set a flag on an image indicating whether or not to use existing alpha
245channel data, to create an alpha channel, or to perform other operations on the alpha channel.  Choose the argument <var>type</var> from the list below.</p>
246
247<div class="pre-scrollable highlight">
248<dl class="row">
249    <dt class="col-md-4">Activate</dt>
250    <dd class="col-md-8">
251       Enable the image's transparency channel. Note normally Set
252       should be used instead of this, unless you specifically need to
253       preserve existing (but specifically turned Off) transparency
254       channel. </dd>
255
256    <dt class="col-md-4">Associate</dt>
257    <dd class="col-md-8">
258       associate the alpha channel with the image.</dd>
259
260    <dt class="col-md-4">Deactivate</dt>
261    <dd class="col-md-8">
262       Disables the image's transparency channel. Does not delete or change the
263       existing data, just turns off the use of that data.</dd>
264
265    <dt class="col-md-4">Disassociate</dt>
266    <dd class="col-md-8">
267       disassociate the alpha channel from the image.</dd>
268
269    <dt class="col-md-4">Set</dt>
270    <dd class="col-md-8">
271       Activates the alpha/matte channel. If it was previously turned off
272       then it also resets the channel to opaque.  If the image already had
273       the alpha channel turned on, it will have no effect.</dd>
274
275    <dt class="col-md-4">Opaque</dt>
276    <dd class="col-md-8">
277       Enables the alpha/matte channel and forces it to be fully opaque.
278       </dd>
279
280    <dt class="col-md-4">Transparent</dt>
281    <dd class="col-md-8">
282       Activates the alpha/matte channel and forces it to be fully
283       transparent. This effectively creates a fully transparent image the
284       same size as the original and with all its original RGB data still
285       intact, but fully transparent. </dd>
286
287    <dt class="col-md-4">Extract</dt>
288    <dd class="col-md-8">
289       Copies the alpha channel values into all the color channels and turns
290       'Off' the image's transparency, so as to generate
291       a grayscale mask of the image's shape. The alpha channel data is left
292       intact just deactivated.  This is the inverse of 'Copy'.
293       </dd>
294
295    <dt class="col-md-4">Copy</dt>
296    <dd class="col-md-8">
297       Turns 'On' the alpha/matte channel, then copies the
298       grayscale intensity of the image, into the alpha channel, converting
299       a grayscale mask into a transparent shaped mask ready to be colored
300       appropriately. The color channels are not modified.  </dd>
301
302    <dt class="col-md-4">Shape</dt>
303    <dd class="col-md-8">
304       As per 'Copy' but also colors the resulting shape mask with
305       the current background color.  That is the RGB color channels is
306       replaced, with appropriate alpha shape.
307       </dd>
308
309    <dt class="col-md-4">Remove</dt>
310    <dd class="col-md-8">
311       Composite the image over the background color.
312       </dd>
313
314    <dt class="col-md-4">Background</dt>
315    <dd class="col-md-8">
316       Set any fully-transparent pixel to the background color, while leaving
317       it fully-transparent.  This can make some image file formats, such as
318       PNG, smaller as the RGB values of transparent pixels are more uniform,
319       and thus can compress better.
320       </dd>
321</dl>
322</div>
323<br/>
324
325<p>Note that while the obsolete <code>+matte</code> operation was the
326same as "<code><a href="command-line-options.html#alpha" >-alpha</a> Off</code>", the <code>
327>-matte</code> operation was the same as "<code><a href="command-line-options.html#alpha" >-alpha</a>
328Set</code>" and not "<code><a href="command-line-options.html#alpha" >-alpha</a> On</code>".  </p>
329
330<div class="pre-scrollable highlight" style="margin: auto;">
331 <h3><a class="anchor" id="annotate"></a>
332 -annotate <var>degrees</var> <var>text</var><br />
333 -annotate <var>Xdegrees</var>x<var>Ydegrees</var> <var>text</var><br /> -annotate <var>Xdegrees</var>x<var>Ydegrees</var>{+-}<var>t<sub>x</sub></var>{+-}<var>t<sub>y</sub></var> <var>text</var><br /> -annotate {+-}<var>t<sub>x</sub></var>{+-}<var>t<sub>y</sub></var> <var>text</var></h3>
334</div>
335
336<p class="magick-description">Annotate an image with text</p>
337
338<p>This is a convenience for annotating an image with text. For more precise
339control over text annotations, use <a href="command-line-options.html#draw">-draw</a>.</p>
340
341
342<p>The values <var>Xdegrees</var> and <var>Ydegrees</var>
343control the shears applied to the text, while <var>t<sub>x</sub></var> and <var>t<sub>y</sub></var> are offsets that give the location of the text relative any <a href="command-line-options.html#gravity" >-gravity</a> setting and defaults to the upper left corner of the image.</p>
344
345<p>Using <a href="command-line-options.html#annotate">-annotate</a> <var>degrees</var>
346or <a href="command-line-options.html#annotate">-annotate</a> <var>degrees</var>x<var>degrees</var> produces an unsheared rotation of the text. The
347direction of the rotation is positive, which means a clockwise rotation if <var>degrees</var> is positive. (This conforms to the usual mathematical
348convention once it is realized that the positive <var>y</var>–direction is
349conventionally considered to be <var>downward</var> for images.)</p>
350
351<p>The new (transformed) coordinates (<var>x'</var>, <var>y'</var>) of a pixel at position (<var>x</var>, <var>y</var>) in the image are calculated using the following matrix
352equation.</p>
353
354<p class="text-center"><img class="img-thumbnail" alt="annotate transformation"  src="../images/annotate.png"/></p>
355
356<p>If <var>t<sub>x</sub></var> and <var>t<sub>y</sub></var> are omitted, they default to 0. This makes the
357bottom-left of the text becomes the upper-left corner of the image, which is
358probably undesirable. Adding a <a href="command-line-options.html#gravity" >-gravity</a> option in this
359case leads to nice results.</p>
360
361<p>Text is any UTF-8 encoded character sequence.  If <var>text</var>
362is of the form '@mytext.txt', the text is read from the file
363<code>mytext.txt</code>.  Text  in a file is taken literally; no embedded
364formatting characters are recognized.</p>
365
366<div style="margin: auto;">
367  <h3><a class="anchor" id="antialias"></a>-antialias</h3>
368</div>
369
370<p class="magick-description">Enable/Disable of the rendering of anti-aliasing pixels when drawing fonts and lines.</p>
371
372<p>By default, objects (e.g. text, lines, polygons, etc.) are antialiased when
373drawn.  Use <a href="command-line-options.html#antialias">+antialias</a> to disable the addition of
374antialiasing edge pixels.  This will then reduce the number of colors added to
375an image to just the colors being directly drawn.  That is, no mixed colors
376are added when drawing such objects. </p>
377
378<div style="margin: auto;">
379  <h3><a class="anchor" id="append"></a>-append</h3>
380</div>
381
382<p class="magick-description">Join current images vertically or horizontally.</p>
383
384<p>This option creates a single longer image, by joining all the current
385images in sequence top-to-bottom. Use <a href="command-line-options.html#append">+append</a> to
386stack images left-to-right. </p>
387
388<p>If they are not of the same width, narrower images are padded with the
389current <a href="command-line-options.html#background">-background</a> color setting, and their
390position relative to each other can be controlled by the current <a
391href="command-line-options.html#gravity">-gravity</a> setting. </p>
392
393
394<div style="margin: auto;">
395  <h3><a class="anchor" id="attenuate"></a>-attenuate <var>value</var></h3>
396</div>
397
398<p class="magick-description">Lessen (or intensify) when adding noise to an image.</p>
399
400<p>If unset the value is equivalent to 1.0, or a maximum noise addition</p>
401
402<div style="margin: auto;">
403  <h3><a class="anchor" id="authenticate"></a>-authenticate <var>password</var></h3>
404</div>
405
406<p class="magick-description">Decrypt a PDF with a password.</p>
407
408<p>Use this option to supply a <var>password</var> for decrypting
409a PDF that has been encrypted using Microsoft Crypto API (MSC API). The
410encrypting using the MSC API is not supported.</p>
411
412<p>For a different encryption method, see <a href="command-line-options.html#encipher">-encipher</a>
413and <a href="command-line-options.html#decipher">-decipher</a>. </p>
414
415
416<div style="margin: auto;">
417  <h3><a class="anchor" id="auto-gamma"></a>-auto-gamma</h3>
418</div>
419
420<p class="magick-description">Automagically adjust gamma level of image.</p>
421
422<p>This calculates the mean values of an image, then applies a calculated  <a
423href="command-line-options.html#gamma" >-gamma</a> adjustment so that the mean color in the
424image will get a value of 50%. </p>
425
426<p>This means that any solid 'gray' image becomes 50% gray. </p>
427
428<p>This works well for real-life images with little or no extreme dark and
429light areas, but tend to fail for images with large amounts of bright sky or
430dark shadows. It also does not work well for diagrams or cartoon like images.
431</p>
432
433<p>It uses the <a href="command-line-options.html#channel" >-channel</a> setting, (including the
434'<var>sync</var>' flag for channel synchronization), to determine which color
435values is used and modified. As the default <a href="command-line-options.html#channel"
436>-channel</a> setting is '<var>RGB,sync</var>', channels are modified
437together by the same gamma value, preserving colors. </p>
438
439
440
441<div style="margin: auto;">
442  <h3><a class="anchor" id="auto-level"></a>-auto-level</h3>
443</div>
444
445<p class="magick-description">Automagically adjust color levels of image.</p>
446
447<p>This is a 'perfect' image normalization operator.  It finds the exact
448minimum and maximum color values in the image and then applies a <a
449href="command-line-options.html#level" >-level</a> operator to stretch the values to the full range of
450values. </p>
451
452<p>The operator is not typically used for real-life images, image scans, or
453JPEG format images, as a single 'out-rider' pixel can set a bad min/max values
454for the <a href="command-line-options.html#level" >-level</a> operation.  On the other hand it is the
455right operator to use for color stretching gradient images being used to
456generate Color lookup tables, distortion maps, or other 'mathematically'
457defined images.  </p>
458
459<p>The operator is very similar to the <a href="command-line-options.html#normalize">-normalize</a>, <a
460href="command-line-options.html#contrast-stretch" >-contrast-stretch</a>, and <a href="command-line-options.html#linear-stretch"
461>-linear-stretch</a> operators, but without 'histogram binning' or 'clipping'
462problems that these operators may have. That is <a href="command-line-options.html#auto-level"
463>-auto-level</a> is the perfect or ideal version these operators. </p>
464
465<p>It uses the <a href="command-line-options.html#channel" >-channel</a> setting, (including the
466special '<var>sync</var>' flag for channel synchronization), to determine
467which color values are used and modified. As the default <a
468href="command-line-options.html#channel" >+channel</a> setting is '<var>RGB,sync</var>', the
469'<var>sync</var>' ensures that the color channels will are modified
470together by the same gamma value, preserving colors, and ignoring
471transparency. </p>
472
473
474<div style="margin: auto;">
475  <h3><a class="anchor" id="auto-orient"></a>-auto-orient</h3>
476</div>
477
478<p class="magick-description">Adjusts an image so that its orientation is suitable for viewing (i.e. top-left orientation).</p>
479
480<p>This operator reads and resets the EXIF image profile setting 'Orientation'
481and then performs the appropriate 90 degree rotation on the image to orient
482the image, for correct viewing. </p>
483
484<p>This EXIF profile setting is usually set using a gravity sensor in digital
485camera, however photos taken directly downward or upward may not have an
486appropriate value.  Also images that have been orientation 'corrected' without
487reseting this setting, may be 'corrected' again resulting in a incorrect
488result.  If the EXIF profile was previously stripped, the  <a
489href="command-line-options.html#auto-orient" >-auto-orient</a> operator will do nothing. </p>
490
491<div style="margin: auto;">
492  <h3><a class="anchor" id="auto-threshold"></a>-auto-threshold <var>method</var></h3>
493</div>
494
495<p class="magick-description">Automatically perform image thresholding.</p>
496
497<p>Here are the valid methods:</p>
498
499<div class="pre-scrollable highlight">
500<dl class="row">
501<dt class="col-md-4">Undefined</dt><dd class="col-md-8">0:  No method specified (equivalent to '<code>OTSU</code>').</dd>
502<dt class="col-md-4">Kapur</dt><dd class="col-md-8">maximum entropy thresholding.</dd>
503<dt class="col-md-4">OTSU</dt><dd class="col-md-8">cluster-based image thresholding.</dd>
504<dt class="col-md-4">Triangle</dt><dd class="col-md-8">a geometric thresholding method.</dd>
505</dl>
506</div>
507
508<p>The computed threshold is returned as the <kbd>auto-threshold:verbose</kbd> image property. To instead print to your device, use <kbd>-define auto-threshold:verbose=true</kbd>.</p>
509
510<div style="margin: auto;">
511  <h3><a class="anchor" id="average"></a>-average</h3>
512</div>
513
514<p class="magick-description">Average a set of images.</p>
515
516<p>An error results if the images are not identically sized.</p>
517
518
519<div style="margin: auto;">
520  <h3><a class="anchor" id="backdrop"></a>-backdrop</h3>
521</div>
522
523<p class="magick-description">Display the image centered on a backdrop.</p>
524
525<p>This backdrop covers the entire workstation screen and is useful for hiding
526other X window activity while viewing the image. The color of the backdrop is
527specified as the background color. The color is specified using the format
528described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
529
530<div style="margin: auto;">
531  <h3><a class="anchor" id="background"></a>-background <var>color</var></h3>
532</div>
533
534<p class="magick-description">Set the background color.</p>
535
536<p>The color is specified using the format described under the <a
537href="command-line-options.html#fill">-fill</a> option. The default background color (if none is
538specified or found in the image) is white.</p>
539
540<div style="margin: auto;">
541  <h3><a class="anchor" id="bench"></a>-bench <var>iterations</var></h3>
542</div>
543
544<p class="magick-description">Measure performance.</p>
545
546<p>Repeat the entire command for the given number of <var>iterations</var> and report the user-time and elapsed time. For instance,
547consider the following command and its output.  Modify the benchmark with the
548-duration to run the benchmark for a fixed number of seconds and -concurrent
549to run the benchmark in parallel (requires the OpenMP feature).</p>
550
551<pre class="highlight"><code>-> convert logo: -resize 200% -bench 5 logo.png
552Performance[1]: 5i 1.344ips 1.000e 3.710u 0:03.720
553Performance[2]: 5i 1.634ips 0.549e 3.890u 0:03.060
554Performance[3]: 5i 2.174ips 0.618e 3.190u 0:02.300
555Performance[4]: 5i 1.678ips 0.555e 3.810u 0:02.980
556Performance[4]: 5i 0.875657ips 6.880u 0:05.710
557</code></pre>
558
559<p>In this example, 5 iterations were completed at 2.174 iterations per
560second, using 3 threads and 3.190 seconds of the user allotted time, for
561a total elapsed time of 2.300 seconds.</p>
562
563<div style="margin: auto;">
564  <h3><a class="anchor" id="bias"></a>-bias <var>value</var>{<var>%</var>}</h3>
565</div>
566
567<p class="magick-description">Add bias when convolving an image.</p>
568
569<p>This option shifts the output of <a class="text-nowrap" href="command-line-options.html#convolve">-convolve</a>  so that
570positive and negative results are relative to the specified bias value. </p>
571
572<p>This is important for non-HDRI compilations of ImageMagick when dealing
573with convolutions that contain negative as well as positive values. This is
574especially the case with convolutions involving high pass filters or edge
575detection. Without an output bias, the negative values are clipped at
576zero.</p>
577
578<p>When using an ImageMagick with the HDRI compile-time setting, <a class="text-nowrap" href="command-line-options.html#bias">-bias</a> is not needed, as ImageMagick is able to store/handle any
579negative results without clipping to the color value range
580(0..QuantumRange).</p>
581
582<p>See the discussion on HDRI implementations of ImageMagick on the page <a
583href="high-dynamic-range.html" >High Dynamic-Range Images</a>. For more
584about HDRI go the ImageMagick <a
585href="https://legacy.imagemagick.org/Usage/basics/#hdri" >Usage</a> pages or this
586<a
587href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a>
588entry.  </p>
589
590<div style="margin: auto;">
591  <h3><a class="anchor" id="bilateral-blur"></a>-bilateral-blur <var>width</var>{x<var>height</var>}{<var>+intensity-sigma</var>}{<var>+spatial-sigma</var>}</h3>
592</div>
593
594<p class="magick-description">A non-linear, edge-preserving, and noise-reducing
595smoothing filter for images.  It replaces the intensity of each pixel with a
596weighted average of intensity values from nearby pixels. This weight is
597based on a Gaussian distribution.  The weights depend not only on Euclidean
598distance of pixels, but also on the radiometric differences (e.g., range
599differences, such as color intensity, depth distance, etc.). This preserves
600sharp edges.</p>
601
602<p>The intensity sigma is in the intensity space. A larger value means
603that farther colors within the pixel neighborhood (see spatial-sigma)
604will be mixed together, resulting in larger areas of semi-equal color.</p>
605
606<p>The spatial sigma is in the coordinate space. A larger value means that
607farther pixels influence each other as long as their colors are close
608enough (see intensity-sigma ). When the neigborhood diameter is greater
609than zero, it specifies the neighborhood size regardless of
610spatial-sigma. Otherwise, the neigborhood diameter is proportional to
611spatial-sigma.</p>
612<p>The default value for the intensity and spatial sigmas are <var>0.75*diameter</var> and <var>0.25*diameter</var> respectively.</p>
613
614
615<div style="margin: auto;">
616  <h3><a class="anchor" id="black-point-compensation"></a>-black-point-compensation</h3>
617</div>
618
619<p class="magick-description">Use black point compensation.</p>
620
621<div style="margin: auto;">
622  <h3><a class="anchor" id="black-threshold"></a>-black-threshold <var>value</var>{<var>%</var>}</h3>
623</div>
624
625<p class="magick-description">Force to black all pixels below the threshold while leaving all pixels at or above the threshold unchanged.</p>
626
627<p> The threshold value can be given as a percentage or as an absolute integer
628value within [0, <var>QuantumRange</var>] corresponding to the
629desired <a class="text-nowrap" href="command-line-options.html#channel">-channel</a> value. See <a class="text-nowrap" href="command-line-options.html#threshold">-threshold</a> for more details on thresholds and resulting values.  </p>
630
631
632<div style="margin: auto;">
633  <h3><a class="anchor" id="blend"></a>-blend <var>geometry</var></h3>
634</div>
635
636<p class="magick-description">Blend an image into another by the given absolute value or percent.</p>
637
638<p>Blend will average the images together ('plus') according to the
639percentages given and each pixels transparency.  If only a single percentage
640value is given it sets the weight of the composite or 'source' image, while
641the background image is weighted by the exact opposite amount. That is a
642<code>-blend 30%</code> merges 30% of the 'source' image with 70% of the
643'destination' image.  Thus it is equivalent to <code>-blend 30x70%</code>.</p>
644
645
646<div style="margin: auto;">
647  <h3><a class="anchor" id="blue-primary"></a>-blue-primary <var>x</var>,<var>y</var></h3>
648</div>
649
650<p class="magick-description">Set the blue chromaticity primary point.</p>
651
652<div style="margin: auto;">
653  <h3><a class="anchor" id="blue-shift"></a>-blue-shift <var>factor</var></h3>
654</div>
655
656<p class="magick-description">Simulate a scene at nighttime in the moonlight.  Start with a factor of 1.5</p>
657
658<div style="margin: auto;">
659
660<div style="margin: auto;">
661  <h3><a class="anchor" id="blur"></a>-blur <var>radius</var><br />-blur <var>radius</var>{x<var>sigma</var>}</h3>
662</div>
663
664<p class="magick-description">Reduce image noise and reduce detail levels.</p>
665
666<p>Convolve the image with a Gaussian or normal distribution using the given
667<var >Sigma</var> value.  The formula is:</p>
668
669<p class="text-center"><img class="img-thumbnail" alt="gaussian distribution" width="243px" height="42px" src="../images/gaussian-blur.png"/></p>
670
671<p>The <var >Sigma</var> value is the important argument, and
672determines the actual amount of blurring that will take place. </p>
673
674<p>The <var >Radius</var> is only used to determine the size of the
675array which will hold the calculated Gaussian distribution. It should be an
676integer.  If not given, or set to zero, IM will calculate the largest possible
677radius that will provide meaningful results for the Gaussian distribution.
678</p>
679
680<p>The larger the <var >Radius</var> the slower the
681operation is. However too small a <var >Radius</var>, and severe
682aliasing effects may result.  As a guideline, <var >Radius</var>
683should be at least twice the <var >Sigma</var> value, though three
684times will produce a more accurate result. </p>
685
686<p>This option differs from <a href="command-line-options.html#gaussian-blur">-gaussian-blur</a> simply
687by taking advantage of the separability properties of the distribution.  Here
688we apply a single-dimensional Gaussian matrix in the horizontal direction,
689then repeat the process in the vertical direction.</p>
690
691<p>The <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting will determine how
692pixels which are outside the image proper are blurred into the final result.
693</p>
694
695
696<div style="margin: auto;">
697  <h3><a class="anchor" id="border"></a>-border <var>geometry</var></h3>
698</div>
699
700<p class="magick-description">Surround the image with a border of color. </p>
701
702<p>Set the width and height using the <var>size</var> portion of the
703<var>geometry</var> argument.  See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. Offsets are
704ignored. </p>
705
706<p>As of IM 6.7.8-8, the <var>geometry</var> arguments behave as follows:</p>
707
708<div class="pre-scrollable highlight">
709<dl class="row">
710<dt class="col-md-4"><var>value</var></dt>
711<dd class="col-md-8">value is added to both left/right and top/bottom</dd>
712<dt class="col-md-4"><var>value-x</var><code>x</code></dt>
713<dd class="col-md-8">value-x is added only to left/right and top/bottom are unchanged</dd>
714<dt class="col-md-4"><code>x</code><var>value-y</var></dt>
715<dd class="col-md-8">value-y is added only to top/bottom and left/right are unchanged</dd>
716<dt class="col-md-4"><var>value-x</var><code>x</code><var>value-y</var></dt>
717<dd class="col-md-8">value-x is added to left/right and value-y added to top/bottom</dd>
718<dt class="col-md-4"><var>value-x</var><code>x</code>0</dt>
719<dd class="col-md-8">value-x is added only to left/right and top/bottom are unchanged</dd>
720<dt class="col-md-4">0<code>x</code><var>value-y</var></dt>
721<dd class="col-md-8">value-y is added only to top/bottom and left/right are unchanged</dd>
722<dt class="col-md-4"><var>value</var>%</dt>
723<dd class="col-md-8">value % of width is added to left/right and value % of height is added to top/bottom</dd>
724<dt class="col-md-4"><var>value-x</var><code>x</code>%</dt>
725<dd class="col-md-8">value-x % of width is added to left/right and to top/bottom</dd>
726<dt class="col-md-4">x<var>value-y</var>%</dt>
727<dd class="col-md-8">value-y % of height is added to top/bottom and to left/right</dd>
728<dt class="col-md-4"><var>value-x</var>%<code>x</code><var>value-y</var>%</dt>
729<dd class="col-md-8">value-x % of width is added to left/right and value-y % of height is added to top/bottom</dd>
730<dt class="col-md-4"><var>value-x</var>%<code>x</code>0%</dt>
731<dd class="col-md-8">value-x % of width is added to left/right and top/bottom are unchanged</dd>
732<dt class="col-md-4">0%<code>x</code><var>value-y</var>%</dt>
733<dd class="col-md-8">value-y % of height is added to top/bottom and left/right are unchanged</dd>
734</dl>
735</div>
736
737<p>Set the border color by preceding with the <a
738href="command-line-options.html#bordercolor">-bordercolor</a> setting.</p>
739
740<p>The <a href="command-line-options.html#border">-border</a> operation is affected by the current <a
741href="command-line-options.html#compose">-compose</a> setting and assumes that this is using the default
742'<code>Over</code>' composition method.  It generates an image of the appropriate
743size colors by the current <a href="command-line-options.html#bordercolor">-bordercolor</a> before
744overlaying the original image in the center of this net image.  This means that
745with the default compose method of '<code>Over</code>' any transparent parts may
746be replaced by the current <a href="command-line-options.html#bordercolor">-bordercolor</a> setting.</p>
747<p>See also the <a href="command-line-options.html#frame">-frame</a> option, which has more
748functionality.</p>
749
750<div style="margin: auto;">
751  <h3><a class="anchor" id="bordercolor"></a>-bordercolor <var>color</var></h3>
752</div>
753
754<p class="magick-description">Set the border color.</p>
755
756<p>The color is specified using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
757
758<p>The default border color is <code>#DFDFDF</code>, <span style="background-color: #dfdfdf;">this shade of gray</span>.</p>
759
760<div style="margin: auto;">
761  <h3><a class="anchor" id="borderwidth"></a>-borderwidth <var>geometry</var> </h3>
762</div>
763
764<p class="magick-description">Set the border width.</p>
765
766<div style="margin: auto;">
767  <h3><a class="anchor" id="brightness-contrast"></a>-brightness-contrast <var>brightness</var><br />-brightness-contrast <var>brightness</var>{x<var>contrast</var>}{<var>%</var>}</h3>
768</div>
769
770<p class="magick-description">Adjust the brightness and/or contrast of the image.</p>
771
772<p>Brightness and Contrast values apply changes to the input image. They are
773not absolute settings. A brightness or contrast value of zero means no change.
774The range of values is -100 to +100 on each. Positive values increase the
775brightness or contrast and negative values decrease the brightness or contrast.
776To control only contrast, set the brightness=0. To control only brightness,
777set contrast=0 or just leave it off.</p>
778
779<p>You may also use <a href="command-line-options.html#fill">-channel</a> to control which channels to
780apply the brightness and/or contrast change. The default is to apply the same
781transformation to all channels.</p>
782
783<p>Brightness and Contrast arguments are converted to offset and slope of a
784linear transform and applied
785using <a href="command-line-options.html#fill">-function polynomial "slope,offset"</a>.</p>
786
787<p>The slope varies from 0 at contrast=-100 to almost vertical at
788contrast=+100. For brightness=0 and contrast=-100, the result are totally
789midgray. For brightness=0 and contrast=+100, the result will approach but
790not quite reach a threshold at midgray; that is the linear transformation
791is a very steep vertical line at mid gray.</p>
792
793<p>Negative slopes, i.e. negating the image, are not possible with this
794function. All achievable slopes are zero or positive.</p>
795
796<p>The offset varies from -0.5 at brightness=-100 to 0 at brightness=0 to +0.5
797at brightness=+100. Thus, when contrast=0 and brightness=100, the result is
798totally white. Similarly, when contrast=0 and brightness=-100, the result is
799totally black.</p>
800
801<p>As the range of values for the arguments are -100 to +100, adding the '%'
802symbol is no different than leaving it off.</p>
803
804<div style="margin: auto;">
805  <h3><a class="anchor" id="cache"></a>-cache <var>threshold</var></h3>
806</div>
807
808<p class="magick-description">(This option has been replaced by the <a href='command-line-options.html#limit'>-limit</a> option).</p>
809
810<div style="margin: auto;">
811  <h3><a class="anchor" id="canny"></a>-canny <var>radius</var><br/>-canny <var>radius</var>{x<var>sigma</var>}{<var>+lower-percent</var>}{<var>+upper-percent</var>}</h3>
812</div>
813
814<p class="magick-description">Canny edge detector uses a multi-stage algorithm to detect a wide range of edges in the image.</p>
815
816<p>The thresholds range from 0 to 100% (e.g. -canny 0x1+10%+30%) with {<var>+lower-percent</var>} &lt; {<var>+upper-percent</var>}. If {<var>+upper-percent</var>} is increased but {<var>+lower-percent</var>} remains the same, lesser edge components will be detected, but their lengths will be the same. If {<var>+lower-percent</var>} is increased but {<var>+upper-percent</var>} is the same, the same number of edge components will be detected but their lengths will be shorter. The default thresholds are shown. The <var>radius</var>{x<var>sigma</var>} controls a gaussian blur applied to the input image to reduce noise and smooth the edges.</p>
817
818<div style="margin: auto;">
819  <h3><a class="anchor" id="caption"></a>-caption <var>string</var></h3>
820</div>
821
822<p class="magick-description">Assign a caption to an image.</p>
823
824<p>This option sets the caption meta-data of an image read in after this
825option has been given.  To modify a caption of images already in memory use
826"<code><a href="command-line-options.html#set">-set</a> caption</code>". </p>
827
828<p>The caption can contain special format characters listed in the <a
829href="../www/escape.html">Format and
830Print Image Properties</a>. These attributes are expanded when the caption
831is finally assigned to the individual images. </p>
832
833<p>If the first character of <var>string</var> is <var>@</var>, the image caption is read from a file titled by the
834remaining characters in the string.  Comments read in from a file are literal;
835no embedded formatting characters are recognized.</p>
836
837<p>Caption meta-data is not visible on the image itself. To do that use the
838<a href="command-line-options.html#annotate">-annotate</a> or <a href="command-line-options.html#draw">-draw</a> options
839instead.</p>
840
841<p>For example,</p>
842
843<pre class="highlight"><code>-caption "%m:%f %wx%h"  bird.miff
844</code></pre>
845
846<p>produces an image caption of <code>MIFF:bird.miff 512x480</code> (assuming
847that the image <code>bird.miff</code> has a width of 512 and a height of
848480.</p>
849
850
851<div style="margin: auto;">
852  <h3><a class="anchor" id="cdl"></a>-cdl <var>filename</var></h3>
853</div>
854
855<p class="magick-description">Color correct with a color decision list.</p>
856
857<p>Here is an example color correction collection:</p>
858
859<pre class="highlight"><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
860&lt;ColorCorrectionCollection xmlns="urn:ASC:CDL:v1.2"&gt;
861  &lt;ColorCorrection id="cc06668"&gt;
862    &lt;SOPNode&gt;
863      &lt;Slope&gt; 0.9 1.2 0.5 &lt;/Slope&gt;
864      &lt;Offset&gt; 0.4 -0.5 0.6 &lt;/Offset&gt;
865      &lt;Power&gt; 1.0 0.8 1.5 &lt;/Power&gt;
866    &lt;/SOPNode&gt;
867    &lt;SATNode&gt;
868      &lt;Saturation&gt; 0.85 &lt;/Saturation&gt;
869    &lt;/SATNode&gt;
870  &lt;/ColorCorrection&gt;
871&lt;/ColorCorrectionCollection&gt;
872</code></pre>
873
874<div style="margin: auto;">
875  <h3><a class="anchor" id="channel"></a>-channel <var>type</var></h3>
876</div>
877
878<p class="magick-description">Specify those image color channels to which subsequent operators are limited.</p>
879
880<p>Choose from: <code>Red</code>, <code>Green</code>, <code>Blue</code>,
881<code>Alpha</code>, <code>Gray</code>, <code>Cyan</code>, <code>Magenta</code>,
882<code>Yellow</code>, <code>Black</code>, <code>Opacity</code>,
883<code>Index</code>, <code>RGB</code>, <code>RGBA</code>, <code>CMYK</code>, or
884<code>CMYKA</code>.</p>
885
886<p>The channels above can also be specified as a comma-separated list or can be
887abbreviated as a concatenation of the letters '<code>R</code>', '<code>G</code>',
888'<code>B</code>', '<code>A</code>', '<code>O</code>', '<code>C</code>',
889'<code>M</code>', '<code>Y</code>', '<code>K</code>'.</p>
890
891<p>The numerals 0 to 31 may also be used to specify channels, where 0 to 5 are: <br />
892<ul>
893'<code>0</code>' equals <code>Red</code> or <code>Cyan</code> <br />
894'<code>1</code>' equals <code>Green</code> or <code>Magenta</code> <br />
895'<code>2</code>' equals <code>Blue</code> or <code>Yellow</code> <br />
896'<code>3</code>' equals <code>Black</code> <br />
897'<code>4</code>' equals <code>Alpha</code> or <code>Opacity</code> <br />
898'<code>5</code>' equals <code>Index</code></p>
899</ul>
900
901<p>For example, to only select the <code>Red</code> and <code>Blue</code> channels
902you can use any of the following:</p>
903<ul><pre class="highlight">
904<code>-channel Red,Blue</code>
905<code>-channel R,B</code>
906<code>-channel RB</code>
907<code>-channel 0,2</code>
908</pre></ul>
909
910<p>All the channels that are present in an image can be specified using the
911special channel type <code>All</code>. Not all operators are 'channel capable',
912but generally any operators that are generally 'grey-scale' image operators,
913will understand this setting.  See individual operator documentation. </p>
914
915<p>On top of the normal channel selection an extra flag can be specified,
916'<code>Sync</code>'.  This is turned on by default and if set means that
917operators that understand this flag should perform: cross-channel
918synchronization of the channels. If not specified, then most grey-scale
919operators will apply their image processing operations to each individual
920channel (as specified by the rest of the <a href="command-line-options.html#channel">-channel</a>
921setting) completely independently from each other. </p>
922
923<p>For example for operators such as <a href="command-line-options.html#auto-level">-auto-level</a> and
924<a href="command-line-options.html#auto-gamma">-auto-gamma</a> the color channels are modified
925together in exactly the same way so that colors will remain in-sync. Without
926it being set, then each channel is modified separately and
927independently, which may produce color distortion. </p>
928
929<p>The <a href="command-line-options.html#morphology">-morphology</a> '<code>Convolve</code>' method
930and the <a href="command-line-options.html#compose">-compose</a> mathematical methods, also understands
931the '<code>Sync</code>' flag to modify the behavior of pixel colors according
932to the alpha channel (if present). That is to say it will modify the image
933processing with the understanding that fully-transparent colors should not
934contribute to the final result. </p>
935
936<p>Basically, by default, operators work with color channels in synchronous, and
937treats transparency as special, unless the <a href="command-line-options.html#channel">-channel</a>
938setting is modified so as to remove the effect of the '<code>Sync</code>' flag.
939How each operator does this depends on that operators current implementation.
940Not all operators understands this flag at this time, but that is changing.
941</p>
942
943<p>To print a complete list of channel types, use <a href="command-line-options.html#list">-list
944channel</a>.</p>
945
946<p>By default, ImageMagick sets <a href="command-line-options.html#channel">-channel</a> to the value
947'<code>RGBK,sync</code>', which specifies that operators act on all color
948channels except the transparency channel, and that all the color channels are
949to be modified in exactly the same way, with an understanding of transparency
950(depending on the operation being applied).  The 'plus' form <a
951href="command-line-options.html#channel" >+channel</a> will reset the value back to this default. </p>
952
953<p>Options that are affected by the <a href="command-line-options.html#channel" >-channel</a> setting
954include the following.
955
956<a href="command-line-options.html#auto-gamma">-auto-gamma</a>,
957<a href="command-line-options.html#auto-level">-auto-level</a>,
958<a href="command-line-options.html#black-threshold">-black-threshold</a>,
959<a href="command-line-options.html#blur">-blur</a>,
960<a href="command-line-options.html#clamp">-clamp</a>,
961<a href="command-line-options.html#clut">-clut</a>,
962<a href="command-line-options.html#combine">-combine</a>,
963<a href="command-line-options.html#composite">-composite</a> (Mathematical compose methods only),
964<a href="command-line-options.html#convolve">-convolve</a>,
965<a href="command-line-options.html#contrast-stretch">-contrast-stretch</a>,
966<a href="command-line-options.html#evaluate">-evaluate</a>,
967<a href="command-line-options.html#function">-function</a>,
968<a href="command-line-options.html#fx">-fx</a>,
969<a href="command-line-options.html#gaussian-blur">-gaussian-blur</a>,
970<a href="command-line-options.html#hald-clut">-hald-clut</a>,
971<a href="command-line-options.html#motion-blur">-motion-blur</a>,
972<a href="command-line-options.html#morphology">-morphology</a>,
973<a href="command-line-options.html#negate">-negate</a>,
974<a href="command-line-options.html#normalize">-normalize</a>,
975<a href="command-line-options.html#ordered-dither">-ordered-dither</a>,
976<a href="command-line-options.html#radial-blur">-radial-blur</a>,
977<a href="command-line-options.html#random-threshold">-random-threshold</a>,
978<a href="command-line-options.html#range-threshold">-range-threshold</a>,
979<a href="command-line-options.html#separate">-separate</a>,
980<a href="command-line-options.html#threshold">-threshold</a>, and
981<a href="command-line-options.html#white-threshold">-white-threshold</a>.
982</p>
983
984<p>Warning, some operators behave differently when the <a href="command-line-options.html#channel"
985>+channel</a> default setting is in effect, versus ANY user defined <a
986href="command-line-options.html#channel" >-channel</a> setting (including the equivalent of the
987default). These operators have yet to be made to understand the newer 'Sync'
988flag. </p>
989
990<p>For example <a href="command-line-options.html#threshold">-threshold</a> will by default grayscale
991the image before thresholding, if no <a href="command-line-options.html#channel" >-channel</a> setting
992has been defined. This is not 'Sync flag controlled, yet. </p>
993
994<p>Also some operators such as <a href="command-line-options.html#blur">-blur</a>, <a
995href="command-line-options.html#gaussian-blur">-gaussian-blur</a>, will modify their handling of the
996color channels if the '<code>alpha</code>' channel is also enabled by <a
997href="command-line-options.html#channel" >-channel</a>.  Generally this done to ensure that
998fully-transparent colors are treated as being fully-transparent, and thus any
999underlying 'hidden' color has no effect on the final results.  Typically
1000resulting in 'halo' effects. The newer <a href="command-line-options.html#morphology">-morphology</a>
1001convolution equivalents however does have a understanding of the 'Sync' flag
1002and will thus handle transparency correctly by default. </p>
1003
1004<p>As an alpha channel is optional within images, some operators will read the
1005color channels of an image as a greyscale alpha mask, when the image has no
1006alpha channel present, and the <a href="command-line-options.html#channel" >-channel</a> setting tells
1007the operator to apply the operation using alpha channels. The <a
1008href="command-line-options.html#clut">-clut</a> operator is a good example of this. </p>
1009
1010<div style="margin: auto;">
1011  <h3><a class="anchor" id="channel-fx"></a>-channel-fx <var>expression</var></h3>
1012</div>
1013
1014<p class="magick-description">Exchange, extract, or copy one or more image channels.</p>
1015
1016<p>The expression consists of one or more channels, either mnemonic or numeric (e.g. red or 0, green or 1, etc.), separated by certain operation symbols as follows:</p>
1017
1018<pre class="highlight"><code>&lt;=&gt;  exchange two channels (e.g. red&lt;=&gt;blue)
1019=&gt;   copy one channel to another channel (e.g. red=&gt;green)
1020=    assign a constant value to a channel (e.g. red=50%)
1021,    write new image with channels in the specified order (e.g. red, green)
1022;    add a new output image for the next set of channel operations (e.g. red; green; blue)
1023|    move to the next input image for the source of channel data (e.g. | gray=>alpha)
1024</code></pre>
1025
1026<p>For example, to create 3 grayscale images from the red, green, and blue channels of an image, use:</p>
1027
1028<pre class="highlight"><code>-channel-fx "red; green; blue"
1029</code></pre>
1030
1031<p>A channel without an operation symbol implies separate (i.e, semicolon).</p>
1032
1033<p>Here we take an sRGB image and a grayscale image and inject the grayscale image into the alpha channel:</p>
1034<pre class="highlight"><code>magick wizard.png mask.pgm -channel-fx '| gray=>alpha' wizard-alpha.png
1035</code></pre>
1036<p>Use a similar command to define a read mask:</p>
1037<pre class="highlight"><code>magick wizard.png mask.pgm -channel-fx '| gray=>read-mask' wizard-mask.png
1038</code></pre>
1039
1040<p>Add <code>-debug pixel</code> prior to the <code>-channel-fx</code> option to track the channel morphology.</p>
1041
1042<div style="margin: auto;">
1043  <h3><a class="anchor" id="charcoal"></a>-charcoal <var>factor</var></h3>
1044</div>
1045
1046<p class="magick-description">Simulate a charcoal drawing.</p>
1047
1048<div style="margin: auto;">
1049  <h3><a class="anchor" id="chop"></a>-chop <var>geometry</var></h3>
1050</div>
1051
1052<p class="magick-description">Remove pixels from the interior of an image.</p>
1053
1054<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. The <var>width</var>
1055and <var>height</var> given in the of the <var>size</var>
1056portion of the <var>geometry</var> argument give the number of
1057columns and rows to remove. The <var>offset</var> portion of
1058the <var>geometry</var> argument is influenced by
1059a <a href="command-line-options.html#gravity">-gravity</a> setting, if present.</p>
1060
1061<p>The <a href="command-line-options.html#chop">-chop</a> option removes entire rows and columns,
1062and moves the remaining corner blocks leftward and upward to close the gaps.</p>
1063
1064<p>While it can remove internal rows and columns of pixels, it is more
1065typically used with as <a href="command-line-options.html#gravity">-gravity</a> setting and zero
1066offsets so as to remove a single edge from an image.  Compare this to <a
1067href="command-line-options.html#shave" >-shave</a> which removes equal numbers of pixels from opposite
1068sides of the image.  </p>
1069
1070<p>Using <a href="command-line-options.html#chop">-chop</a> effectively undoes the results of a <a
1071href="command-line-options.html#splice">-splice</a> that was given the same <var>geometry</var> and <a href="command-line-options.html#gravity">-gravity</a> settings. </p>
1072
1073<div style="margin: auto;">
1074  <h3><a class="anchor" id="clahe"></a>-clahe <var>width</var>x<var>height</var>{%}{+}<var>number-bins</var>{+}<var>clip-limit</var>{!}</h3>
1075</div>
1076
1077<p class="magick-description">Contrast limited adaptive histogram equalization.</p>
1078<p> The image is divided into tiles of <var>width</var> and <var>height</var> pixels.  Append <code>%</code> to define the width and height as percentages of the image's dimensions. The tile size should be larger than the size of features to be preserved and respects the aspect ratio of the image.  Add <code>!</code> to force an exact tile width and height. <var>number-bins</var> is the number of histogram bins per tile (min 2, max 65536).  The number of histogram bins should be smaller than the number of pixels in a single tile. <var>clip-limit</var> is the contrast limit for localized changes in contrast. A clip-limit of 2 to 3 is a good starting place (e.g. -clahe 50x50%+128+3).  Very large values will let the histogram equalization do whatever it wants to do, that is result in maximal local contrast. The value 1 will result in the original image.  Note, if the number of bins and the clip-limit are ommitted, they default to 128 and no clipping respectively.</p>
1079
1080
1081<div style="margin: auto;">
1082  <h3><a class="anchor" id="clamp"></a>-clamp</h3>
1083</div>
1084
1085<p class="magick-description">Set each pixel whose value is below zero to zero and any the pixel whose value is above the quantum range to the quantum range (e.g. 65535) otherwise the pixel value remains unchanged.</p>
1086
1087<div style="margin: auto;">
1088  <h3><a class="anchor" id="clip"></a>-clip</h3>
1089</div>
1090
1091<p class="magick-description">Apply the clipping path if one is present.</p>
1092
1093<p>If a clipping path is present, it is applied to subsequent operations.</p>
1094
1095<p>For example, in the command</p>
1096
1097<pre class="highlight"><code>magick cockatoo.tif -clip -negate negated.tif
1098</code></pre>
1099
1100<p>only the pixels within the clipping path are negated.</p>
1101
1102<p>The <a href="command-line-options.html#clip">-clip</a> feature requires SVG support. If the SVG
1103delegate library is not present, the option is ignored.</p>
1104
1105<p>Use <a href="command-line-options.html#clip">+clip</a> to disable clipping for subsequent operations.</p>
1106
1107<div style="margin: auto;">
1108  <h3><a class="anchor" id="clip-mask"></a>-clip-mask</h3>
1109</div>
1110
1111<p class="magick-description">Clip the image as defined by this mask.</p>
1112
1113<p>Use the alpha channel of the current image as a mask.  Any areas that is
1114white is not modified by any of the 'image processing operators' that follow,
1115until the mask is removed. Pixels in the black areas of the clip mask are
1116modified per the requirements of the operator. </p>
1117
1118<p>In some ways this is similar to (though not the same) as defining
1119a rectangular <a href="command-line-options.html#region" >-region</a>, or using the negative of the
1120mask (third) image in a three image <a href="command-line-options.html#composite" >-composite</a>,
1121operation. </p>
1122
1123<p>Use <a href="command-line-options.html#clip-mask">+clip-mask</a> to disable clipping for subsequent operations.</p>
1124
1125<div style="margin: auto;">
1126  <h3><a class="anchor" id="clip-path"></a>-clip-path <var>id</var></h3>
1127</div>
1128
1129<p class="magick-description">Clip along a named path from the 8BIM profile.</p>
1130
1131<p>This is identical to <a href="command-line-options.html#clip">-clip</a> except choose a specific clip path in the event the image has more than one path available. </p>
1132
1133<p>Use <a href="command-line-options.html#clip-path">+clip-path</a> to disable clipping for subsequent operations.</p>
1134
1135<div style="margin: auto;">
1136  <h3><a class="anchor" id="clone"></a>-clone <var>index(s)</var></h3>
1137</div>
1138
1139<p class="magick-description">Make a clone of an image (or images).</p>
1140
1141<p>Inside parenthesis (where the operator is normally used) it will make a
1142clone of the images from the last 'pushed' image sequence, and adds them to
1143the end of the current image sequence. Outside parenthesis
1144(not recommended) it clones the images from the current image sequence. </p>
1145
1146<p>Specify the image by its index in the sequence.  The first image is index
11470.  Negative indexes are relative to the end of the sequence; for
1148example, <code>−1</code>
1149represents the last image of the sequence.  Specify a range of images with a
1150dash (e.g. <code>0−4</code>).  Separate multiple indexes with commas but no
1151spaces (e.g. <code>0,2,5</code>).  A value of '<code>0−−1</code> will
1152effectively clone all the images. </p>
1153
1154<p>The <a href="command-line-options.html#clone">+clone</a> will simply make a copy of the last image
1155in the image sequence, and is thus equivalent to using an argument of
1156'<code>−1</code>'. </p>
1157
1158<div style="margin: auto;">
1159  <h3><a class="anchor" id="clut"></a>-clut</h3>
1160</div>
1161
1162<p class="magick-description">Replace the channel values in the first image using each corresponding channel in the second image as a <b>c</b>olor <b>l</b>ook<b>u</b>p <b>t</b>able.</p>
1163
1164<p>The second (LUT) image is ordinarily a gradient image containing the
1165histogram mapping of how each channel should be modified. Typically it is a
1166either a single row or column image of replacement color values. If larger
1167than a single row or column, values are taken from a diagonal line from
1168top-left to bottom-right corners.</p>
1169
1170<p>The lookup is further controlled by the <a
1171href="command-line-options.html#interpolate">-interpolate</a> setting, which is especially handy for an
1172LUT which is not the full length needed by the ImageMagick installed Quality
1173(Q) level. Good settings for this are '<code>bilinear</code>' and
1174'<code>catrom</code>'. Catom can return a useful second-order continuity.</p>
1175
1176<p>This operator is especially suited to replacing a grayscale image with a
1177specific color gradient from the CLUT image. </p>
1178
1179<p>Only the channel values defined by the <a href="command-line-options.html#channel">-channel</a>
1180setting will have their values replaced. In particular, since the default <a
1181href="command-line-options.html#channel">-channel</a> setting is <code>RGB</code>, this means that
1182transparency (alpha/matte channel) is not affected, unless the <a
1183href="command-line-options.html#channel">-channel</a> setting is modified. When the alpha channel is
1184set, it is treated by the <a href="command-line-options.html#clut" >-clut</a> operator in the same way
1185as the other channels, implying that alpha/matte values are replaced using the
1186alpha/matte values of the original image. </p>
1187
1188<p>If either the image being modified, or the lookup image, contains no
1189transparency (i.e. <a href="command-line-options.html#alpha" >-alpha</a> is turned 'off') but the <a
1190href="command-line-options.html#channel">-channel</a> setting includes alpha replacement, then it is
1191assumed that image represents a grayscale gradient which is used for the
1192replacement alpha values.  That is you can use a grayscale CLUT image to
1193adjust a existing images alpha channel, or you can color a grayscale image
1194using colors form CLUT containing the desired colors, including transparency.
1195</p>
1196
1197<p>See also <a href="command-line-options.html#hald-clut" >-hald-clut</a> which replaces colors
1198according to the lookup of the full color RGB value from a 2D representation
1199of a 3D color cube. </p>
1200
1201
1202<div style="margin: auto;">
1203  <h3><a class="anchor" id="coalesce"></a>-coalesce</h3>
1204</div>
1205
1206<p class="magick-description">Fully define the look of each frame of an GIF animation sequence, to form a 'film strip' animation.</p>
1207
1208<p>Overlay each image in an image sequence according to
1209its <a href="command-line-options.html#dispose">-dispose</a> meta-data, to reproduce the look of
1210an animation at each point in the animation sequence. All images should be
1211the same size, and are assigned appropriate GIF disposal settings for the
1212animation to continue working as expected as a GIF animation.  Such frames
1213are more easily viewed and processed than the highly optimized GIF overlay
1214images.  </p>
1215
1216<p>The animation can be re-optimized after processing using
1217the <a href="command-line-options.html#layers">-layers</a> method '<code>optimize</code>', although
1218there is no guarantee that the restored GIF animation optimization is
1219better than the original. </p>
1220
1221
1222<div style="margin: auto;">
1223  <h3><a class="anchor" id="colorize"></a>-colorize <var>value</var></h3>
1224</div>
1225
1226<p class="magick-description">Colorize the image by an amount specified by <var>value</var> using the color specified by the most recent <a href="command-line-options.html#fill" >-fill</a> setting.</p>
1227
1228<p>Specify the amount of colorization as a percentage. Separate colorization
1229values can be applied to the red, green, and blue channels of the image with
1230a comma-delimited list of colorization
1231values (e.g., <code>-colorize 0,0,50</code>).</p>
1232
1233<div style="margin: auto;">
1234  <h3><a class="anchor" id="colormap"></a>-colormap <var>type</var></h3>
1235</div>
1236
1237<p class="magick-description">Define the colormap type.</p>
1238
1239<p>The <var>type</var> can be  <code>shared</code> or <code>private</code>.</p>
1240
1241<p>This option only applies when the default X server visual
1242is <code>PseudoColor</code> or <code>GrayScale</code>. Refer
1243to <a href="command-line-options.html#visual">-visual</a> for more details. By default,
1244a shared colormap is allocated. The image shares colors with
1245other X clients. Some image colors could be approximated,
1246therefore your image may look very different than intended.
1247If <code>private</code> is chosen, the image colors appear exactly
1248as they are defined. However, other clients may go <var>technicolor</var>
1249when the image colormap is installed.</p>
1250
1251<div style="margin: auto;">
1252  <h3><a class="anchor" id="colors"></a>-colors <var>value</var></h3>
1253</div>
1254
1255<p class="magick-description">Set the preferred number of colors in the image.</p>
1256
1257<p>The actual number of colors in the image may be less than your request,
1258but never more. Note that this a color reduction option. Images with fewer
1259unique colors than specified by <var>value</var> will have any
1260duplicate or unused colors removed.  The ordering of an existing color
1261palette may be altered. When converting an image from color to grayscale,
1262it is more efficient to convert the image to the gray colorspace before
1263reducing the number of colors. Refer to
1264the <a href="../www/quantize.html">
1265color reduction algorithm</a> for more details.</p>
1266
1267<div style="margin: auto;">
1268  <h3><a class="anchor" id="color-matrix"></a>-color-matrix <var>matrix</var></h3>
1269</div>
1270
1271<p class="magick-description">Apply color correction to the image.</p>
1272
1273<p>This option permits saturation changes, hue rotation, luminance to alpha,
1274and various other effects.  Although variable-sized transformation matrices
1275can be used, typically one uses a 5x5 matrix for an RGBA image and a 6x6
1276for CMYKA (or RGBA with offsets).  The matrix is similar to those used by
1277Adobe Flash except offsets are in column 6 rather than 5 (in support of
1278CMYKA images) and offsets are normalized (divide Flash offset by 255).</p>
1279
1280<p>As an example, to add contrast to an image with offsets, try this command:</p>
1281
1282<pre class="highlight"><code>magick kittens.jpg -color-matrix \
1283  " 1.5 0.0 0.0 0.0, 0.0, -0.157 \
1284    0.0 1.5 0.0 0.0, 0.0, -0.157 \
1285    0.0 0.0 1.5 0.0, 0.0, -0.157 \
1286    0.0 0.0 0.0 1.0, 0.0,  0.0 \
1287    0.0 0.0 0.0 0.0, 1.0,  0.0 \
1288    0.0 0.0 0.0 0.0, 0.0,  1.0" kittens.png
1289</code></pre>
1290<div style="margin: auto;">
1291  <h3><a class="anchor" id="colorspace"></a>-colorspace <var>value</var></h3>
1292</div>
1293
1294<p class="magick-description">Set the image colorspace.</p>
1295
1296<p>Choices are:</p>
1297
1298<pre class="highlight"><code>CMY          CMYK         Gray         HCL
1299HCLp         HSB          HSI          HSL
1300HSV          HWB          Jzazbz       Lab
1301LCHab        LCHuv        LMS          Log
1302Luv          OHTA         Rec601YCbCr  Rec709YCbCr
1303RGB          scRGB        sRGB         Transparent
1304xyY          XYZ          YCbCr        YCC
1305YDbDr        YIQ          YPbPr        YUV
1306Undefined
1307</code></pre>
1308
1309<p>To print a complete list of colorspaces, use <a href="command-line-options.html#list">-list colorspace</a>.</p>
1310
1311<p>For a more accurate color conversion to or from the linear RGB, CMYK, or grayscale colorspaces, use the <a href="command-line-options.html#profile">-profile</a> option.  Note, ImageMagick assumes the sRGB colorspace if the image format does not indicate otherwise.  For colorspace conversion, the gamma function is first removed to produce linear RGB.</p>
1312
1313<div class="pre-scrollable highlight">
1314<table class="table table-sm table-hover">
1315        <caption>Conversion of RGB to Other Color Spaces</caption>
1316        <tr><th valign="middle">CMY</th></tr>
1317        <tr><td valign="middle">C=<var>QuantumRange</var>−R</td></tr>
1318        <tr><td valign="middle">M=<var>QuantumRange</var>−G</td></tr>
1319        <tr><td valign="middle">Y=<var>QuantumRange</var>−B</td></tr>
1320        <tr><th valign="middle">CMYK — starts with CMY from above</th></tr>
1321        <tr><td valign="middle">K=min(C,Y,M)</td></tr>
1322        <tr><td valign="middle">C=<var>QuantumRange</var>*(C−K)/(<var>QuantumRange</var>−K)</td></tr>
1323        <tr><td valign="middle">M=<var>QuantumRange</var>*(M−K)/(<var>QuantumRange</var>−K)</td></tr>
1324        <tr><td valign="middle">Y=<var>QuantumRange</var>*(Y−K)/(<var>QuantumRange</var>−K)</td></tr>
1325
1326        <tr><th valign="middle">Gray</th></tr>
1327        <tr><td valign="middle">Gray = 0.212656*R+0.715158*G+0.072186*B</td></tr>
1328
1329        <tr><th valign="middle">HSB — Hue, Saturation, Brightness; like a cone peak downward</th></tr>
1330        <tr><td valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr>
1331        <tr><td valign="middle">S=distance from axis outward</td></tr>
1332        <tr><td valign="middle">B=distance along axis from bottom upward; B=max(R,G,B); <var>intensity-like</var></td></tr>
1333
1334        <tr><th valign="middle">HSL — Hue, Saturation, Lightness; like a double cone end-to-end with peaks at very top and bottom</th></tr>
1335        <tr><td valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr>
1336        <tr><td valign="middle">S=distance from axis outward</td></tr>
1337        <tr><td valign="middle">L=distance along axis from bottom upward; L=0.5*max(R,G,B) + 0.5*min(R,G,B); <var>intensity-like</var></td></tr>
1338
1339        <tr><th valign="middle">HWB — Hue, Whiteness, Blackness</th></tr>
1340        <tr><td valign="middle">Hue (complicated equation)</td></tr>
1341        <tr><td valign="middle">Whiteness (complicated equation)</td></tr>
1342        <tr><td valign="middle">Blackness (complicated equation)</td></tr>
1343
1344        <tr><th valign="middle">LAB</th></tr>
1345        <tr><td valign="middle">L (complicated equation relating X,Y,Z)</td></tr>
1346        <tr><td valign="middle">A (complicated equation relating X,Y,Z)</td></tr>
1347        <tr><td valign="middle">B (complicated equation relating X,Y,Z)</td></tr>
1348        <tr><th valign="middle">LinearGray</th></tr>
1349        <tr><td valign="middle">LinearGray = 0.298839*R+0.586811*G+0.114350*B</td></tr>
1350
1351        <tr><th valign="middle">LOG</th></tr>
1352        <tr><td valign="middle">I1 (complicated equation involving logarithm of R)</td></tr>
1353        <tr><td valign="middle">I2 (complicated equation involving logarithm of G)</td></tr>
1354        <tr><td valign="middle">I3 (complicated equation involving logarithm of B)</td></tr>
1355
1356        <tr><th valign="middle">OHTA — approximates principal components transformation</th></tr>
1357        <tr><td valign="middle">I1=0.33333*R+0.33334*G+0.33333*B; <var>intensity-like</var></td></tr>
1358        <tr><td valign="middle">I2=(0.50000*R+0.00000*G−0.50000*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1359        <tr><td valign="middle">I3=(−0.25000*R+0.50000*G−0.25000*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1360
1361        <tr><th valign="middle">Rec601Luma</th></tr>
1362        <tr><td valign="middle">Gray = 0.298839*R+0.586811*G+0.114350*B</td></tr>
1363
1364        <tr><th valign="middle">Rec601YCbCr</th></tr>
1365        <tr><td valign="middle">Y=0.2988390*R+0.5868110*G+0.1143500*B; <var>intensity-like</var></td></tr>
1366        <tr><td valign="middle">Cb=(−0.168736*R-0.331264*G+0.500000*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1367        <tr><td valign="middle">Cr=(0.500000*R−0.418688*G−0.081312*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1368
1369        <tr><th valign="middle">Rec709Luma</th></tr>
1370        <tr><td valign="middle">Gray=0.212656*R+0.715158*G+0.072186*B</td></tr>
1371
1372        <tr><th valign="middle">Rec709YCbCr</th></tr>
1373        <tr><td valign="middle">Y=0.212656*R+0.715158*G+0.072186*B; <var>intensity-like</var></td></tr>
1374        <tr><td valign="middle">Cb=(−0.114572*R−0.385428*G+0.500000*B)+(<var>QuantumRange</var>+1)/2</td></tr>
1375        <tr><td valign="middle">Cr=(0.500000*R−0.454153*G−0.045847*B)+(<var>QuantumRange</var>+1)/2</td></tr>
1376        <tr><th valign="middle">sRGB</th></tr>
1377        <tr><td valign="middle">if R ≤ .0.0031308 then Rs=R/12.92 else Rs=1.055 R ^ (1.0 / 2.4) - 0.055</td></tr>
1378        <tr><td valign="middle">if G ≤ .0.0031308 then Gs=B/12.92 else Gs=1.055 R ^ (1.0 / 2.4) - 0.055</td></tr>
1379        <tr><td valign="middle">if B ≤ .0.0031308 then Bs=B/12.92 else Bs=1.055 R ^ (1.0 / 2.4) - 0.055</td></tr>
1380
1381        <tr><th valign="middle">XYZ</th></tr>
1382        <tr><td valign="middle">X=0.4124564*R+0.3575761*G+0.1804375*B</td></tr>
1383        <tr><td valign="middle">Y=0.2126729*R+0.7151522*G+0.0721750*B</td></tr>
1384        <tr><td valign="middle">Z=0.0193339*R+0.1191920*G+0.9503041*B</td></tr>
1385
1386        <tr><th valign="middle">YCC</th></tr>
1387        <tr><td valign="middle">Y=(0.298839*R+0.586811*G+0.114350*B) (with complicated scaling); <var>intensity-like</var></td></tr>
1388        <tr><td valign="middle">C1=(−0.298839*R−0.586811*G+0.88600*B) (with complicated scaling)</td></tr>
1389        <tr><td valign="middle">C2=(0.70100*R−0.586811*G−0.114350*B) (with complicated scaling)</td></tr>
1390
1391        <tr><th valign="middle">YCbCr</th></tr>
1392        <tr><td valign="middle">Y=0.2988390*R+0.5868110*G+0.1143500*B; <var>intensity-like</var></td></tr>
1393        <tr><td valign="middle">Cb=(−0.168736*R−0.331264*G+0.500000*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1394        <tr><td valign="middle">Cr=(0.500000*R−0.418688*G−0.081312*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1395
1396        <tr><th valign="middle">YIQ</th></tr>
1397        <tr><td valign="middle">Y=0.298839*R+0.586811*G+0.114350*B; <var>intensity-like</var></td></tr>
1398        <tr><td valign="middle">I=(0.59600*R−0.27400*G−0.32200*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1399        <tr><td valign="middle">Q=(0.21100*R−0.52300*G+0.31200*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1400
1401        <tr><th valign="middle">YPbPr</th></tr>
1402        <tr><td valign="middle">Y=0.2988390*R+0.5868110*G+0.1143500*B; <var>intensity-like</var></td></tr>
1403        <tr><td valign="middle">Pb=(−0.168736*R−0.331264*G+0.500000*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1404        <tr><td valign="middle">Pr=(0.500000*R−0.418688*G−0.081312*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1405
1406        <tr><th valign="middle">YUV</th></tr>
1407        <tr><td valign="middle">Y=0.298839*R+0.586811*G+0.114350*B; <var>intensity-like</var></td></tr>
1408        <tr><td valign="middle">U=(−0.14740*R−0.28950*G+0.43690*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1409        <tr><td valign="middle">V=(0.61500*R−0.51500*G−0.10000*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1410</table>
1411</div>
1412
1413<p>Note the scRGB colorspace requires HDRI support otherwise it behaves just like linear RGB.</p>
1414
1415<p>Use the <code>Undefined</code> colorspace to identify multi-spectral images.</p>
1416
1417<div style="margin: auto;">
1418  <h3><a class="anchor" id="color-threshold"></a>-color-threshold <var>start-color</var>-<var>stop-color</var></h3>
1419</div>
1420
1421<p>Return a binary image where all colors within the specified range are changed to white.  All other colors are changed to black.</p>
1422
1423<div style="margin: auto;">
1424  <h3><a class="anchor" id="combine"></a>-combine</h3>
1425  <h3>+combine <var>colorspace</var></h3>
1426</div>
1427
1428<p class="magick-description">Combine one or more images into a single image.</p>
1429
1430<p>The channels (previously set by <a href="command-line-options.html#channel">-channel</a>) of the
1431combined image are taken from the grayscale values of each image in the
1432sequence, in order. For the default -channel setting of <code>RGB</code>, this
1433means the first image  is assigned to the <code>Red</code> channel, the second
1434to the <code>Green</code> channel, the third to the <code>Blue</code>.</p>
1435
1436<p>This option can be thought of as the inverse to <a
1437href="command-line-options.html#separate">-separate</a>, so long as the channel settings are the same.
1438Thus, in the following example, the final image should be a copy of the
1439original.  </p>
1440
1441<pre class="highlight"><code>magick original.png -channel RGB -separate sepimage.png
1442convert sepimage-0.png sepimage-1.png sepimage-2.png -channel RGB \
1443  -combine imagecopy.png
1444</code></pre>
1445
1446<div style="margin: auto;">
1447  <h3><a class="anchor" id="comment"></a>-comment <var>string</var></h3>
1448</div>
1449
1450<p class="magick-description">Embed a comment in an image.</p>
1451
1452<p>This option sets the comment meta-data of an image read in after this
1453option has been given.  To modify a comment of images already in memory use
1454"<code><a href="command-line-options.html#set">-set</a> comment</code>". </p>
1455
1456<p>The comment can contain special format characters listed in the <a
1457href="../www/escape.html">Format and
1458Print Image Properties</a>. These attributes are expanded when the comment
1459is finally assigned to the individual images. </p>
1460
1461<p>If the first character of <var>string</var> is <var>@</var>, the image comment is read from a file titled by the
1462remaining characters in the string.  Comments read in from a file are literal;
1463no embedded formatting characters are recognized.</p>
1464
1465<p>Comment meta-data are not visible on the image itself. To do that use the
1466<a href="command-line-options.html#annotate">-annotate</a> or <a href="command-line-options.html#draw">-draw</a> options
1467instead.</p>
1468
1469<p>For example,</p>
1470
1471<pre class="highlight"><code>-comment "%m:%f %wx%h"  bird.miff
1472</code></pre>
1473
1474<p>produces an image comment of <code>MIFF:bird.miff 512x480</code> (assuming
1475that the image <code>bird.miff</code> has a width of 512 and a height of
1476480.</p>
1477
1478<div style="margin: auto;">
1479  <h3><a class="anchor" id="compare"></a>-compare</h3>
1480</div>
1481
1482<p class="magick-description">Mathematically and visually annotate the difference between an image and its reconstruction</p>
1483
1484<p>This is a convert version of "<code>compare</code>" for two same sized images. The syntax is as follows, but other metrics are allowed.</p>
1485
1486<pre class="highlight"><code>magick image.png reference.png -metric RMSE -compare \ <br/> difference.png
1487</code></pre>
1488
1489<p>To get the metric value use the string format "%[distortion]".</p>
1490
1491<pre class="highlight"><code>magick image.png reference.png -metric RMSE -compare -format \
1492   "%[distortion]" info:
1493</code></pre>
1494
1495<div style="margin: auto;">
1496  <h3><a class="anchor" id="complex"></a>-complex <var>operator</var></h3>
1497</div>
1498
1499<p class="magick-description">Perform complex mathematics on an image sequence</p>
1500
1501Choose from these operators:
1502
1503<pre class="highlight"><code>add
1504conjugate
1505divide
1506magnitude-phase
1507multiply
1508real-imaginary
1509subtract
1510</code></pre>
1511
1512<p>Optionally specify the <code>divide</code> operator SNR with <code><a href="command-line-options.html#define">-define</a> complex:snr=float</code>.</p>
1513
1514<div style="margin: auto;">
1515  <h3><a class="anchor" id="compose"></a>-compose <var>operator</var></h3>
1516</div>
1517
1518<p class="magick-description">Set the type of image composition.</p>
1519
1520<p>See <a href="../www/compose.html">Alpha Compositing</a> for
1521a detailed discussion of alpha compositing.</p>
1522
1523<p>This setting affects image processing operators that merge two (or more)
1524images together in some way.  This includes the operators,
1525<a href="command-line-options.html#composite">-compare</a>,
1526<a href="command-line-options.html#composite">-composite</a>,
1527<a href="command-line-options.html#layers">-layers</a> composite,
1528<a href="command-line-options.html#flatten">-flatten</a>,
1529<a href="command-line-options.html#mosaic">-mosaic</a>,
1530<a href="command-line-options.html#layers">-layers</a> merge,
1531<a href="command-line-options.html#border">-border</a>,
1532<a href="command-line-options.html#frame">-frame</a>,
1533and <a href="command-line-options.html#extent">-extent</a>. </p>
1534
1535<p>It is also one of the primary options for the "<code>composite</code>"
1536command.  </p>
1537
1538
1539<div style="margin: auto;">
1540  <h3><a class="anchor" id="composite"></a>-composite</h3>
1541</div>
1542
1543<p class="magick-description">Perform alpha composition on two images and an optional mask</p>
1544
1545<p>Take the first image 'destination' and overlay the second 'source' image
1546according to the current <a href="command-line-options.html#compose">-compose</a> setting. The location
1547of the 'source' or 'overlay' image is controlled according to <a
1548href="command-line-options.html#gravity" >-gravity</a>, and <a href="command-line-options.html#geometry" >-geometry</a>
1549settings. </p>
1550
1551<p>If a third image is given this is treated as a grayscale blending 'mask' image
1552relative to the first 'destination' image. This mask is blended with the
1553source image.  However for the '<code>displace</code>' compose method, the
1554mask is used to provide a separate Y-displacement image instead. </p>
1555
1556<p>If a <a href="command-line-options.html#compose">-compose</a> method requires extra numerical
1557arguments or flags these can be provided by setting the  <a
1558href="command-line-options.html#set">-set</a> '<code>option:compose:args</code>'
1559appropriately for the compose method. </p>
1560
1561<p>Some <a href="command-line-options.html#compose">-compose</a> methods can modify the 'destination'
1562image outside the overlay area. It is disabled by default.  You can enable this by setting the define: <a href="command-line-options.html#define">-define</a> '<code>compose:clip-to-self=true</code>'.</p>
1563
1564<p>The SVG compositing specification requires that color and opacity values range between zero and QuantumRange inclusive.  You can permit values outside this range with this option: <a href="command-line-options.html#set">-set</a> '<code>option:compose:clamp=false</code></p>
1565
1566
1567<div style="margin: auto;">
1568  <h3><a class="anchor" id="compress"></a>-compress <var>type</var></h3>
1569</div>
1570
1571<p class="magick-description">Use pixel compression specified by <var>type</var> when writing the image.</p>
1572
1573<p>Choices are: <code>None</code>, <code>BZip</code>, <code
1574>Fax</code>, <code>Group4</code>, <code
1575>JPEG</code>,  <code>JPEG2000</code>, <code
1576>Lossless</code>, <code>LZW</code>, <code
1577>RLE</code> or <code>Zip</code>.</p>
1578
1579<p>To print a complete list of compression types, use <a href="command-line-options.html#list">-list
1580compress</a>.</p>
1581
1582<p>Specify <a href="command-line-options.html#compress">+compress</a> to store the binary image in an
1583uncompressed format. The default is the compression type of the specified
1584image file.</p>
1585
1586<p>If <code>LZW</code> compression is specified but LZW compression has not been
1587enabled, the image data is written in an uncompressed LZW format that can be
1588read by LZW decoders. This may result in larger-than-expected GIF files.</p>
1589
1590<p><code>Lossless</code> refers to lossless JPEG, which is only available if the
1591JPEG library has been patched to support it. Use of lossless JPEG is generally
1592not recommended.</p>
1593
1594<p>
1595When writing an ICO file, you may request that the images be encoded in
1596PNG format, by specifying <code>Zip</code> compression.</p>
1597
1598<p>
1599When writing a JNG file, specify <code>Zip</code> compression to request that
1600the alpha channel be encoded in PNG "IDAT" format, or <code>JPEG</code>
1601to request that it be encoded in JPG "JDAA" format.</p>
1602
1603<p>Use the <a href="command-line-options.html#quality">-quality</a> option to set the compression level
1604to be used by JPEG, PNG, MIFF, and MPEG encoders.
1605Use the <a href="command-line-options.html#sampling-factor">-sampling-factor</a> option to set the
1606sampling factor to be used by JPEG, MPEG, and YUV encoders for down-sampling
1607the chroma channels.</p>
1608
1609<div style="margin: auto;">
1610  <h3><a class="anchor" id="connected-components"></a>-connected-components <var>connectivity</var></h3>
1611</div>
1612
1613<p class="magick-description"><a href="../www/connected-components.html">connected-components</a> labeling detects connected regions in an image, choose from 4 or 8 way connectivity.</p>
1614
1615<p>Use <code><a href="command-line-options.html#define" >-define</a> connected-components:verbose=true</code> to output statistics associated with each unique label.</p>
1616
1617<div style="margin: auto;">
1618  <h3><a class="anchor" id="contrast"></a>-contrast</h3>
1619</div>
1620
1621<p class="magick-description">Enhance or reduce the image contrast.</p>
1622
1623<p>This option enhances the intensity differences between the lighter and
1624darker elements of the image. Use <a href="command-line-options.html#contrast">-contrast</a> to enhance
1625the image or <a href="command-line-options.html#contrast">+contrast</a> to reduce the image
1626contrast.</p>
1627
1628<p>For a more pronounced effect you can repeat the option:</p>
1629
1630<pre class="highlight"><code>magick rose: -contrast -contrast rose_c2.png
1631</code></pre>
1632
1633<div style="margin: auto;">
1634  <h3><a class="anchor" id="contrast-stretch"></a>-contrast-stretch <var>black-point</var><br />-contrast-stretch <var>black-point</var>{x<var>white-point</var>}{<var>%</var>}</h3>
1635</div>
1636
1637<p class="magick-description">Increase the contrast in an image by <var>stretching</var> the range of intensity values.</p>
1638
1639<p>While performing the stretch, black-out at most <var>black-point</var> pixels and white-out at most <var>white-point</var> pixels. Or, if percent is used, black-out at most
1640<var >black-point %</var> pixels and white-out at most <var>white-point %</var> pixels.</p>
1641
1642<p>Prior to ImageMagick 6.4.7-0, <a href="command-line-options.html#contrast-stretch"
1643>-contrast-stretch</a> will black-out at most <var>black-point</var> pixels and white-out at most <var >total pixels
1644minus white-point</var> pixels. Or, if percent is used, black-out at most <var>black-point %</var> pixels and white-out at most <var>100% minus white-point %</var> pixels.</p>
1645
1646<p>Note that <code>-contrast-stretch 0</code> will modify the image such that
1647the image's min and max values are stretched to 0 and <var>QuantumRange</var>, respectively, without any loss of data due to burn-out or
1648clipping at either end. This is not the same as <a href="command-line-options.html#normalize"
1649>-normalize</a>, which is equivalent to <code>-contrast-stretch 0.15x0.05%</code> (or
1650prior to ImageMagick 6.4.7-0, <code>-contrast-stretch 2%x99%</code>).</p>
1651
1652<p>Internally operator works by creating a histogram bin, and then uses that
1653bin to modify the image. As such some colors may be merged together when they
1654originally fell into the same 'bin'. </p>
1655
1656<p>All the channels are normalized in concert by the same amount so as to
1657preserve color integrity, when the default <a href="command-line-options.html#channel" >+channel</a>
1658setting is in use.  Specifying any other <a href="command-line-options.html#channel" >-channel</a>
1659setting will normalize the RGB channels independently.</p>
1660
1661<p>See also  <a href="command-line-options.html#auto-level" >-auto-level</a> for a 'perfect'
1662normalization of mathematical images. </p>
1663
1664<p>This operator is under review for re-development. </p>
1665
1666
1667<div style="margin: auto;">
1668  <h3><a class="anchor" id="convolve"></a>-convolve <var>kernel</var></h3>
1669</div>
1670
1671<p class="magick-description">Convolve an image with a user-supplied convolution kernel.</p>
1672
1673<p>The <var>kernel</var> is a matrix specified as
1674a comma-separated list of integers (with no spaces), ordered left-to right,
1675starting with the top row. Presently, only odd-dimensioned kernels are
1676supported, and therefore the number of entries in the specified <var>kernel</var> must be 3<sup>2</sup>=9, 5<sup>2</sup>=25,
16777<sup>2</sup>=49, etc. </p>
1678
1679<p>Note that the <a class="text-nowrap" href="command-line-options.html#convolve">-convolve</a> operator supports the <a class="text-nowrap" href="command-line-options.html#bias">-bias</a> setting. This option shifts the convolution so that
1680positive and negative results are relative to a user-specified bias value.
1681This is important for non-HDRI compilations of ImageMagick when dealing with
1682convolutions that contain negative as well as positive values. This is
1683especially the case with convolutions involving high pass filters or edge
1684detection. Without an output bias, the negative values is clipped at zero.
1685</p>
1686
1687<p>When using an ImageMagick with the HDRI compile-time setting, <a class="text-nowrap" href="command-line-options.html#bias">-bias</a> is not needed, as ImageMagick is able to store/handle any
1688negative results without clipping to the color value range (0..QuantumRange).
1689See the discussion on HDRI implementations of ImageMagick on the page <a
1690href="high-dynamic-range.html">High
1691Dynamic-Range Images</a>. For more about HDRI go the ImageMagick <a
1692href="https://legacy.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this
1693<a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a>
1694entry.  </p>
1695
1696
1697<div style="margin: auto;">
1698  <h3><a class="anchor" id="copy"></a>-copy <var>geometry</var> <var>offset</var></h3>
1699</div>
1700
1701<p class="magick-description">Copy pixels from one area of an image to another.</p>
1702
1703<div style="margin: auto;">
1704  <h3><a class="anchor" id="crop"></a>-crop <var>geometry</var>{<var>@</var>}{<var>!</var>}</h3>
1705</div>
1706
1707<p class="magick-description">Cut out one or more rectangular regions of the image.</p>
1708
1709<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
1710
1711<p>The <var>width</var> and <var>height</var> of the <var>geometry</var> argument give the size of the image that remains
1712after cropping, and <var>x</var> and <var>y</var> in the
1713<var>offset</var> (if present) gives the location of the top left
1714corner of the cropped image with respect to the original image. To specify the
1715amount to be removed, use <a href="command-line-options.html#shave">-shave</a> instead.</p>
1716
1717<p>If the <var>x</var> and <var>y</var> offsets are
1718present, a single image is generated, consisting of the pixels from the
1719cropping region. The offsets specify the location of the upper left corner of
1720the cropping region measured downward and rightward with respect to the upper
1721left corner of the image. If the <a href="command-line-options.html#gravity">-gravity</a> option is
1722present with <code>NorthEast</code>, <code>East</code>, or <code>SouthEast</code>
1723gravity, it gives the distance leftward from the right edge of the image to
1724the right edge of the cropping region. Similarly, if the <a
1725href="command-line-options.html#gravity">-gravity</a> option is present with <code>SouthWest</code>,
1726<code>South</code>, or <code>SouthEast</code> gravity, the distance is measured
1727upward between the bottom edges.</p>
1728
1729<p>If the <var>x</var> and <var>y</var> offsets are
1730omitted, a set of tiles of the specified geometry, covering the entire input
1731image, is generated. The rightmost tiles and the bottom tiles are smaller if
1732the specified geometry extends beyond the dimensions of the input image.</p>
1733
1734<p>You can add the <var>@</var> to the geometry argument to equally divide the image into the number of tiles generated.</p>
1735
1736<p>By adding a exclamation character flag to the geometry argument, the
1737cropped images virtual canvas page size and offset is set as if the
1738geometry argument was a viewport or window. This means the canvas page size
1739is set to exactly the same size you specified, the image offset set
1740relative top left corner of the region cropped. </p>
1741
1742<p>If the cropped image 'missed' the actual image on its virtual canvas, a
1743special single pixel transparent 'missed' image is returned, and a 'crop
1744missed' warning given. </p>
1745
1746<p>It might be necessary to <a href="command-line-options.html#repage" >+repage</a> the image prior to
1747cropping the image to ensure the crop coordinate frame is relocated to the
1748upper-left corner of the visible image.
1749
1750Similarly you may want to use <a href="command-line-options.html#repage" >+repage</a> after cropping to
1751remove the page offset that will be left behind. This is especially true when
1752you are going to write to an image format such as PNG that supports an image
1753offset.</p>
1754
1755<div style="margin: auto;">
1756  <h3><a class="anchor" id="cycle"></a>-cycle <var>amount</var></h3>
1757</div>
1758
1759<p class="magick-description">Displace image colormap by amount.</p>
1760
1761<p><var>Amount</var> defines the number of positions each
1762colormap entry is shifted.</p>
1763
1764
1765<div style="margin: auto;">
1766  <h3><a class="anchor" id="debug"></a>-debug <var>events</var></h3>
1767</div>
1768
1769<p class="magick-description">Enable debug printout.</p>
1770
1771<p>The <code>events</code> parameter specifies which events are to be logged. It
1772can be either <code>None</code>, <code>All</code>, <code>Trace</code>, or
1773a comma-separated list consisting of one or more of the following domains:
1774<code>Accelerate</code>, <code>Annotate</code>, <code>Blob</code>, <code>Cache</code>,
1775<code>Coder</code>, <code>Configure</code>, <code>Deprecate</code>,
1776<code>Exception</code>, <code>Locale</code>, <code>Render</code>,
1777<code>Resource</code>, <code>Security</code>, <code>TemporaryFile</code>,
1778<code>Transform</code>, <code>X11</code>, or <code>User</code>. </p>
1779
1780
1781<p>For example, to log cache and blob events, use.</p>
1782
1783<pre class="highlight"><code>magick -debug "Cache,Blob" rose: rose.png
1784</code></pre>
1785
1786<p>The <code>User</code> domain is normally empty, but developers can log user
1787events in their private copy of ImageMagick.</p>
1788
1789<p>To print the complete list of debug methods, use <a href="command-line-options.html#list">-list
1790debug</a>.</p>
1791
1792<p>Use the <a href="command-line-options.html#log">-log</a> option to specify the format for debugging
1793output.</p>
1794
1795<p>Use <a href="command-line-options.html#debug">+debug</a> to turn off all logging.</p>
1796
1797<p>Debugging may also be set using the <code>MAGICK_DEBUG</code> <a href="../www/resources.html#environment"
1798>environment variable</a>.  The allowed values for the <code>MAGICK_DEBUG</code>
1799environment variable are the same as for the <a href="command-line-options.html#debug">-debug</a>
1800option.</p>
1801
1802
1803<div style="margin: auto;">
1804  <h3><a class="anchor" id="decipher"></a>-decipher <var>filename</var></h3>
1805</div>
1806
1807<p class="magick-description">Decipher and restore pixels that were previously transformed by <a href="command-line-options.html#encipher">-encipher</a>.</p>
1808
1809<p>Get the passphrase from the file specified by <var>filename</var>.</p>
1810
1811<p>For more information, see the webpage, <a href="../www/cipher.html">ImageMagick: Encipher or
1812Decipher an Image</a>.</p>
1813
1814
1815<div style="margin: auto;">
1816  <h3><a class="anchor" id="deconstruct"></a>-deconstruct</h3>
1817</div>
1818
1819<p class="magick-description">Find areas that has changed between images </p>
1820
1821<p>Given a sequence of images all the same size, such as produced by <a
1822href="command-line-options.html#coalesce">-coalesce</a>, replace the second and later images, with
1823a smaller image of just the area that changed relative to the previous image.
1824</p>
1825
1826<p>The resulting sequence of images can be used to optimize an animation
1827sequence, though will not work correctly for GIF animations when parts of the
1828animation can go from opaque to transparent. </p>
1829
1830<p>This option is actually equivalent to the  <a href="command-line-options.html#layers">-layers</a>
1831method '<code>compare-any</code>'. </p>
1832
1833
1834<div style="margin: auto;">
1835  <h3><a class="anchor" id="define"></a>-define <var>key</var>{<var>=value</var>}<var>...</var></h3>
1836</div>
1837
1838<p class="magick-description">Add specific global settings generally used to control coders and image processing operations.</p>
1839
1840<p>This option creates one or more definitions for coders and decoders to use
1841while reading and writing image data.  Definitions are generally used to
1842control image file format coder modules, and image processing operations,
1843beyond what is provided by normal means.  Defined settings are listed in <a
1844href="command-line-options.html#verbose" >-verbose</a> information ("<code>info:</code>" output format)
1845as "Artifacts". </p>
1846
1847<p>If <var>value</var> is missing for a definition, an empty-valued
1848definition of a flag is created with that name. This used to control on/off
1849options.  Use <a href="command-line-options.html#define">+define key</a> to remove definitions
1850previously created.  Use <a href="command-line-options.html#define">+define "*"</a> to remove all
1851existing definitions.</p>
1852
1853<p>The same 'artifact' settings can also be defined using the <a
1854href="command-line-options.html#set" >-set "option:<var>key</var>" "<var>value</var>"</a> option, which also allows the use of <a href="../www/escape.html" >Format and Print Image
1855Properties</a> in the defined value. </p>
1856
1857<p>The <var>option</var> and <var>key</var> are case-independent (they are
1858converted to lowercase for use within the decoders) while the <var>value</var>
1859is case-dependent.</p>
1860
1861<p>Such settings are global in scope, and affect all images and operations. </p>
1862
1863<p>See <a href="../www/defines.html">ImageMagick Defines</a> for a list of recognized defines.  For example:</p>
1864
1865<pre class="highlight"><code>magick bilevel.tif -define ps:imagemask eps3:stencil.ps
1866</code></pre>
1867
1868<p>Set attributes of the image registry by prefixing the value with
1869<code>registry:</code>.  For example, to set a temporary path to put work files,
1870use:</p>
1871
1872<pre class="highlight"><code>-define registry:temporary-path=/data/tmp
1873</code></pre>
1874
1875<div style="margin: auto;">
1876  <h3><a class="anchor" id="delay"></a>-delay <var>ticks</var> <br />-delay <var>ticks</var>x<var>ticks-per-second</var> {<var>&lt;</var>} {<var>&gt;</var>}</h3>
1877</div>
1878
1879<p class="magick-description">Display the next image after pausing.</p>
1880
1881<p>This option is useful for regulating the animation of image sequences
1882<var>ticks/ticks-per-second</var> seconds must expire before the display of the
1883next image. The default is no delay between each showing of the image
1884sequence.  The default ticks-per-second is 100.</p>
1885
1886<p>Use <code>&gt;</code> to change the image delay <var>only</var> if its current
1887value exceeds the given delay. <code>&lt;</code> changes the image delay
1888<var>only</var> if current value is less than the given delay.  For example, if
1889you specify <code>30&gt;</code> and the image delay is 20, the image delay does
1890not change. However, if the image delay is 40 or 50, the delay it is changed
1891to 30. Enclose the given delay in quotation marks to prevent the
1892<code>&lt;</code> or <code>&gt;</code> from being interpreted by your shell as
1893a file redirection.</p>
1894
1895
1896<div style="margin: auto;">
1897  <h3><a class="anchor" id="delete"></a>-delete <var>indexes</var></h3>
1898</div>
1899
1900<p class="magick-description">Delete the images specified by index, from the image sequence.</p>
1901
1902<p>Specify the image by its index in the sequence.  The first image is index
19030.  Negative indexes are relative to the end of the sequence, for example, -1
1904represents the last image of the sequence.  Specify a range of images with
1905a dash (e.g. 0-4).  Separate indexes with a comma (e.g. 0,2).  Use
1906<code>+delete</code> to delete the last image in the current image sequence. Use <code>-delete 0--1</code> to delete the entire image sequence.</p>
1907
1908
1909<div style="margin: auto;">
1910  <h3><a class="anchor" id="density"></a>-density <var>width</var><br />-density <var>width</var>x<var>height</var></h3>
1911</div>
1912
1913<p class="magick-description">Set the horizontal and vertical resolution of an image for rendering to devices.</p>
1914
1915<p>This option specifies the image resolution to store while encoding a raster
1916image or the canvas resolution while rendering (reading) vector formats such
1917as Postscript, PDF, WMF, and SVG into a raster image. Image resolution
1918provides the unit of measure to apply when rendering to an output device or
1919raster image. The default unit of measure is in dots per inch (DPI). The <a
1920href="command-line-options.html#units">-units</a> option may be used to select dots per centimeter
1921instead.</p>
1922
1923<p>The default resolution is 72 dots per inch, which is equivalent to one
1924point per pixel (Macintosh and Postscript standard). Computer screens are
1925normally 72 or 96 dots per inch, while printers typically support 150, 300,
1926600, or 1200 dots per inch. To determine the resolution of your display, use
1927a ruler to measure the width of your screen in inches, and divide by the
1928number of horizontal pixels (1024 on a 1024x768 display).</p>
1929
1930<p>If the file format supports it, this option may be used to update the
1931stored image resolution. Note that Photoshop stores and obtains image
1932resolution from a proprietary embedded profile. If this profile is not
1933stripped from the image, then Photoshop will continue to treat the image using
1934its former resolution, ignoring the image resolution specified in the standard
1935file header.</p>
1936
1937<p>The <a href="command-line-options.html#density">-density</a> option sets an <var>attribute</var> and
1938does not alter the underlying raster image. It may be used to adjust the
1939rendered size for desktop publishing purposes by adjusting the scale applied
1940to the pixels. To resize the image so that it is the same size at a different
1941resolution, use the <a href="command-line-options.html#resample">-resample</a> option.</p>
1942
1943<div style="margin: auto;">
1944  <h3><a class="anchor" id="depth"></a>-depth <var>value</var></h3>
1945</div>
1946
1947<p class="magick-description">Depth of the image.</p>
1948
1949<p>This the number of bits in a color sample within a pixel.  Use this option
1950to specify the depth of raw images whose depth is unknown such as GRAY, RGB,
1951or CMYK, or to change the depth of any image after it has been read.</p>
1952
1953<p>Use <a href="command-line-options.html#depth">+depth</a> to return depth to its default value.</p>
1954
1955<div style="margin: auto;">
1956  <h3><a class="anchor" id="descend"></a>-descend</h3>
1957</div>
1958
1959<p class="magick-description">Obtain image by descending window hierarchy.</p>
1960
1961<div style="margin: auto;">
1962  <h3><a class="anchor" id="deskew"></a>-deskew <var>threshold{%}</var></h3>
1963</div>
1964
1965<p class="magick-description">Straighten an image.  A threshold of 40% works for most images.</p>
1966
1967<p>Use <a href="command-line-options.html#set">-set</a> <code>option:deskew:auto-crop
1968<var>true | false</var></code> to auto crop the image.</p>
1969
1970<div style="margin: auto;">
1971  <h3><a class="anchor" id="despeckle"></a>-despeckle</h3>
1972</div>
1973
1974<p class="magick-description">Reduce the speckles within an image.</p>
1975
1976<div style="margin: auto;">
1977  <h3><a class="anchor" id="direction"></a>-direction <var>type</var></h3>
1978</div>
1979
1980<p class="magick-description">Render text right-to-left or left-to-right.  Requires the <a href="https://github.com/HOST-Oman/libraqm">RAQM</a> delegate library and <a href="https://en.wikipedia.org/wiki/Complex_text_layout">complex text layout</a>.</p>
1981
1982<div style="margin: auto;">
1983  <h3><a class="anchor" id="displace"></a>-displace <var>horizontal-scale</var>{%}{!}<br />-displace <var>horizontal-scale</var>x<var>vertical-scale</var>{%}{!}</h3>
1984</div>
1985
1986<p class="magick-description">Shift image pixels as defined by a displacement map.</p>
1987
1988<p>With this option, the 'overlay' image, and optionally the 'mask' image,
1989is used as a displacement map, which is used to displace the lookup of
1990what part of the 'background' image is seen at each point of the overlaid
1991area.  Much like the displacement map is a 'lens' that redirects light shining
1992through it so as to present a distorted view the original 'background' image
1993behind it. </p>
1994
1995<p>Any perfect grey areas of the displacement map produce a zero
1996displacement of the image. Black areas produce the given maximum negative
1997displacement of the lookup point, while white produce a maximum positive
1998displacement of the lookup. </p>
1999
2000<p>Note that it is the lookup of the 'background' that is displaced, not a
2001displacement of the image itself. As such an area of the displacement map
2002containing 'white' will have the lookup point 'shifted' by a positive amount,
2003and thus generating a copy of the destination image to the right/downward from
2004the correct position.  That is the image will look like it may have been
2005'shifted' in a negative left/upward direction.  Understanding this is a very
2006important in understanding how displacement maps work.  </p>
2007
2008<p>The given arguments define the maximum amount of displacement in pixels
2009that a particular map can produce. If the displacement scale is large enough
2010it is also possible to lookup parts of the 'background' image that lie well
2011outside the bounds of the displacement map itself.  That is you could very
2012easily copy a section of the original image from outside the overlay area
2013into the overlay area. </p>
2014
2015<p>The '%' flag makes the displacement scale relative to the size of the
2016overlay image (100% = half width/height of image). Using '!' switches
2017percentage arguments to refer to the destination image size instead.
2018these flags were added as of IM v6.5.3-5.</p>
2019
2020<p>Normally a single grayscale displacement map is provided, which with the
2021given scaling values will determine a single direction (vector) in which
2022displacements can occur (positively or negatively).  However, if you also
2023specify a third image which is normally used as a <var>mask</var>,
2024the <var>composite image</var> is used for horizontal X
2025displacement, while the <var>mask image</var> is used for vertical Y
2026displacement.  This allows you to define completely different displacement
2027values for the X and Y directions, and allowing you to lookup any point within
2028the  <var>scale</var> bounds.  In other words each pixel can lookup
2029any other nearby pixel, producing complex 2 dimensional displacements, rather
2030than a simple 1 dimensional vector displacements. </p>
2031
2032<p>Alternatively rather than supplying two separate images, as of IM v6.4.4-0,
2033you can use the 'red' channel of the overlay image to specify the horizontal
2034or X displacement, and the 'green' channel for the vertical or Y displacement.
2035</p>
2036
2037<p>As of IM v6.5.3-5 any alpha channel in the overlay image is used as a
2038mask the transparency of the destination image. However areas outside the
2039overlaid areas will not be affected. </p>
2040
2041
2042<div style="margin: auto;">
2043  <h3><a class="anchor" id="display"></a>-display <var>host:display[.screen]</var></h3>
2044</div>
2045
2046<p class="magick-description">Specifies the X server to contact.</p>
2047
2048<p>This option is used with convert for obtaining image or font from this
2049X server. See <var>X(1)</var>.</p>
2050
2051<div style="margin: auto;">
2052  <h3><a class="anchor" id="dispose"></a>-dispose <var>method</var></h3>
2053</div>
2054
2055<p class="magick-description">Define the GIF disposal image setting for images that are being created or read in. </p>
2056
2057<p>The layer disposal method defines the way each the displayed image is to be
2058modified after the current 'frame' of an animation has finished being
2059displayed (after its 'delay' period), but before the next frame on an
2060animation is to be overlaid onto the display. </p>
2061
2062<p>Here are the valid methods:</p>
2063
2064<div class="pre-scrollable highlight">
2065<dl class="row">
2066<dt class="col-md-4">Undefined</dt><dd class="col-md-8">0:  No disposal specified (equivalent to '<code>none</code>').</dd>
2067<dt class="col-md-4">None</dt><dd class="col-md-8">1:  Do not dispose, just overlay next frame image.</dd>
2068<dt class="col-md-4">Background</dt><dd class="col-md-8">2:  Clear the frame area with the background color.</dd>
2069<dt class="col-md-4">Previous</dt><dd class="col-md-8">3:  Clear to the image prior to this frames overlay.</dd>
2070</dl>
2071</div>
2072
2073<p>You can also use the numbers given above, which is what the GIF format
2074uses internally to represent the above settings. </p>
2075
2076<p>To print a complete list of dispose methods, use <a href="command-line-options.html#list">-list dispose</a>.</p>
2077
2078<p>Use <a href="command-line-options.html#dispose" >+dispose</a>, turn off the setting and prevent
2079resetting the layer disposal methods of images being read in. </p>
2080
2081<p>Use <a href="command-line-options.html#set">-set</a> '<code>dispose</code>' method to set the image
2082disposal method for images already in memory.</p>
2083
2084<div style="margin: auto;">
2085  <h3><a class="anchor" id="dissimilarity-threshold"></a>-dissimilarity-threshold <var>value</var></h3>
2086</div>
2087
2088<p class="magick-description">Maximum RMSE for subimage match (default 0.2).</p>
2089
2090
2091<div style="margin: auto;">
2092  <h3><a class="anchor" id="dissolve"></a>-dissolve <var>src_percent</var>[x<var>dst_percent</var>]</h3>
2093</div>
2094
2095<p class="magick-description">Dissolve an image into another by the given percent.</p>
2096
2097<p>The opacity of the composite image is multiplied by the given percent, then
2098it is composited 'over' the main image.  If <var>src_percent</var>
2099is greater than 100, start dissolving the main image so it becomes
2100transparent at a value of '<code>200</code>'.  If both percentages
2101are given, each image are dissolved to the percentages given. </p>
2102
2103<p>Note that dissolve percentages do not add, two opaque images dissolved
2104'50,50', produce a 75% transparency. For a 50% + 50% blending of the two
2105images, you would need to use dissolve values of '50,100'.  </p>
2106
2107<div style="margin: auto;">
2108  <h3><a class="anchor" id="distort"></a>-distort <var>method arguments</var></h3>
2109</div>
2110
2111<p class="magick-description">Distort an image, using the given <var>method</var> and its required <var>arguments</var>.</p>
2112
2113<p>The <var>arguments</var> is a single string containing a list
2114of floating point numbers separated by commas or spaces.  The number of
2115and meaning of the floating point values depends on the distortion <var>method</var> being used. </p>
2116
2117<p>Choose from these distortion types:</p>
2118
2119<div class="pre-scrollable highlight">
2120<table class="table table-sm table-hover">
2121  <tr>
2122    <th style="width: 8%">Method</th>
2123    <th>Description</th>
2124  </tr>
2125
2126  <tr>
2127    <td>ScaleRotateTranslate <br/> SRT</td>
2128    <td>
2129       Distort image by first scaling and rotating about a given 'center',
2130       before translating that 'center' to the new location, in that order. It
2131       is an alternative method of specifying a 'Affine' type of
2132       distortion, but without shearing effects.  It also provides a good way
2133       of rotating and displacing a smaller image for tiling onto a larger
2134       background (IE 2-dimensional animations). <br/>
2135
2136       The number of arguments determine the specific meaning of each
2137       argument for the scales, rotation, and translation operations. <br/>
2138
2139       <dl class="row">
2140       <dt class="col-md-4">2:</dt><dd class="col-md-8"><var>Scale   Angle</var></dd>
2141       <dt class="col-md-4">3:</dt><dd class="col-md-8"><var>X,Y     Angle</var></dd>
2142       <dt class="col-md-4">4:</dt><dd class="col-md-8"><var>X,Y   Scale   Angle</var></dd>
2143       <dt class="col-md-4">5:</dt> <dd class="col-md-8"><var>X,Y   ScaleX,ScaleY   Angle</var></dd>
2144       <dt class="col-md-4">6:</dt> <dd class="col-md-8"><var>X,Y   Scale   Angle   NewX,NewY</var></dd>
2145       <dt class="col-md-4">7:</dt> <dd class="col-md-8"><var>X,Y   ScaleX,ScaleY   Angle NewX,NewY</var></dd>
2146       </dl>
2147
2148       This is actually an alternative way of specifying a 2 dimensional linear
2149       'Affine' or 'AffineProjection' distortion.  </td> </tr>
2150
2151  <tr>
2152    <td>Affine</td>
2153    <td>
2154       Distort the image linearly by moving a list of at least 3 or more sets
2155       of control points (as defined below).  Ideally 3 sets or 12 floating
2156       point values are given allowing the image to be linearly scaled,
2157       rotated, sheared, and translated, according to those three points. See
2158       also the related 'AffineProjection' and 'SRT'
2159       distortions. <br/>
2160
2161       More than 3 sets given control point pairs (12 numbers) is least
2162       squares fitted to best match a linear affine distortion. If only 2
2163       control point pairs (8 numbers) are given a two point image translation
2164       rotation and scaling is performed, without any possible  shearing,
2165       flipping or changes in aspect ratio to the resulting image. If only one
2166       control point pair is provides the image is only translated, (which may
2167       be a floating point non-integer translation). <br/>
2168
2169       This distortion does not include any form of perspective distortion.
2170       </td>
2171
2172  </tr>
2173
2174  <tr>
2175    <td>RigidAffine</td>
2176    <td>
2177       A rigid affine (also known as a Euclidean transform), is similar to Affine but restricts the distortion to 4 arguments (S, R, Tx, Ty) with Sy = Sx and Ry = -Rx so that the distortion only has scale, rotation and translation. No skew. A minimum of two control point pairs is required.
2178     </td>
2179  </tr>
2180
2181  <tr>
2182    <td>AffineProjection</td>
2183    <td>
2184       Linearly distort an image using the given Affine Matrix of 6
2185       pre-calculated coefficients forming a set of Affine Equations to map
2186       the source image to the destination image.
2187
2188       <p class="text-center"><var>
2189       s<sub>x</sub>, r<sub>x</sub>,
2190       r<sub>y</sub>, s<sub>y</sub>,
2191       t<sub>x</sub>, t<sub>y</sub>
2192       </var></p>
2193
2194       See <a href="command-line-options.html#affine" >-affine</a> setting for more detail, and
2195       meanings of these coefficients. <br/>
2196
2197       The distortions 'Affine' and 'SRT' provide
2198       alternative methods of defining this distortion, with ImageMagick doing
2199       the calculations needed to generate the required coefficients. You can
2200       see the internally generated coefficients, by using a <a
2201       href="command-line-options.html#verbose" >-verbose</a> setting with those other variants.  </td>
2202
2203  </tr>
2204
2205  <tr>
2206    <td>BilinearForward<br/>
2207    BilinearReverse</td>
2208    <td>
2209       Bilinear Distortion, given a minimum of 4 sets of coordinate pairs, or
2210       16 values (see below). Not that lines may not appear straight after
2211       distortion, though the distance between coordinates will remain
2212       consistent. <br/>
2213
2214       The 'BilinearForward' is used to map rectangles to any
2215       quadrilateral, while the 'BilinearReverse' form maps any
2216       quadrilateral to a rectangle, while preserving the straight line edges
2217       in each case.  <br/>
2218
2219       Note that 'BilinearForward' can generate invalid pixels
2220       which will be colored using the <a href="command-line-options.html#mattecolor" >-mattecolor</a>
2221       color setting.  Also if the quadrilateral becomes 'flipped' the image
2222       may disappear. <br/>
2223
2224       There are future plans to produce a true Bilinear distortion that will
2225       attempt to map any quadrilateral to any other quadrilateral, while
2226       preserving edges (and edge distance ratios).
2227
2228       </td>
2229  </tr>
2230
2231  <tr>
2232    <td>Perspective</td>
2233    <td>
2234       Perspective distort the images, using a list of 4 or more sets of
2235       control points (as defined below).  More that 4 sets (16 numbers) of
2236       control points provide least squares fitting for more accurate
2237       distortions (for the purposes of image registration and panorama
2238       effects).  Less than 4 sets will fall back to a 'Affine'
2239       linear distortion.  <br/>
2240
2241       Perspective Distorted images ensures that straight lines remain
2242       straight, but the scale of the distorted image will vary. The horizon
2243       is anti-aliased, and the 'sky' color may be set using the
2244       <a href="command-line-options.html#mattecolor" >-mattecolor</a> setting. </td>
2245  </tr>
2246
2247  <tr>
2248    <td>PerspectiveProjection  </td>
2249    <td>
2250       Do a 'Perspective' distortion biased on a set of 8
2251       pre-calculated coefficients. You can get these coefficients by looking
2252       at the <a href="command-line-options.html#verbose" >-verbose</a> output of a
2253       'Perspective' distortion, or by calculating them yourself.
2254       If the last two perspective scaling coefficients are zero, the
2255       remaining 6 represents a transposed 'Affine Matrix'. </td>
2256  </tr>
2257
2258  <tr>
2259    <td>Polynomial</td>
2260    <td>
2261       Do an Nth order 2D 'Polynomial' distortion using a set of corresponding
2262       control points. The order of the polynomial dictates the minimum number of
2263       control points needed. Order 1 is the same as -distort Affine. Order 1.5 is the
2264       same as -distort BilinearReverse. Typical use is for a 2nd order distortion.
2265       There is no +distort polynomial.</td>
2266  </tr>
2267
2268  <tr>
2269    <td>Arc</td>
2270    <td>
2271       Arc the image (variation of polar mapping) over the angle given around
2272       a circle.
2273
2274       <dl class="row">
2275       <dt class="col-md-4">arc_angle</dt>
2276           <dd class="col-md-8">The angle over which to arc the image side-to-side</dd>
2277       <dt class="col-md-4">rotate_angle</dt>
2278           <dd class="col-md-8">Angle to rotate resulting image from vertical center</dd>
2279       <dt class="col-md-4">top_radius</dt>
2280           <dd class="col-md-8">Set top edge of source image at this radius</dd>
2281       <dt class="col-md-4">bottom_radius </dt>
2282           <dd class="col-md-8">Set bottom edge to this radius (radial scaling)</dd>
2283       </dl>
2284
2285       The resulting image is always resized to best fit the resulting image,
2286       (as if using <a href="command-line-options.html#distort" >+distort</a>) while attempting to
2287       preserve scale and aspect ratio of the original image as much as
2288       possible with the arguments given by the user. All four arguments will
2289       be needed to change the overall aspect ratio of an 'Arc'ed image. <br/>
2290
2291       This a variation of a polar distortion designed to try to preserve the
2292       aspect ratio of the image rather than direct Cartesian to Polar
2293       conversion. </td>
2294  </tr>
2295
2296  <tr>
2297    <td>Polar</td>
2298    <td>
2299       Like 'Arc' but do a complete Cartesian to Polar mapping of
2300       the image. that is the height of the input image is mapped to the
2301       radius limits, while the width is wrapped around between the
2302       angle limits. <br/>
2303
2304       Arguments: <var>Rmax,Rmin CenterX,CenterY, start,end_angle</var> <br/>
2305
2306       All arguments are optional. With <var>Rmin</var> defaulting to zero, the
2307       center to the center of the image, and the angles going from -180 (top)
2308       to +180 (top).  If <var>Rmax</var> is given the special value of
2309       '0', the distance from the center to the nearest edge
2310       is used for the radius of the output image, which will ensure the whole
2311       image is visible (though scaled smaller).  However a special value of
2312       '-1' will use the distance from the center to the furthest
2313       corner,  This may 'clip' the corners from the input rectangular image,
2314       but will generate the exact reverse of a 'DePolar' with
2315       the same arguments. <br/>
2316
2317       If the plus form of distort (<a href="command-line-options.html#distort" >+distort</a>) is used
2318       output image center will default to 0,0 of the virtual
2319       canvas, and the image size adjusted to ensure the whole input image is
2320       made visible in the output image on the virtual canvas. </td>
2321
2322  </tr>
2323
2324  <tr>
2325    <td>DePolar</td>
2326    <td>
2327       Uses the same arguments and meanings as a 'Polar' distortion
2328       but generates the reverse Polar to Cartesian distortion. <br/>
2329
2330       The special <var>Rmax</var> setting of '0' may however clip
2331       the corners of the input image.  However using the special
2332       <var>Rmax</var> setting of '-1' (maximum center to corner
2333       distance) will ensure the whole distorted image is preserved in the
2334       generated result, so that the same argument to 'Polar' will
2335       reverse the distortion re-producing the original.
2336
2337       Note that as this distortion requires the area resampling of a circular
2338       arc, which can not be handled by the builtin EWA resampling function.
2339       As such the normal EWA filters are turned off. It is recommended some
2340       form of 'super-sampling' image processing technique be used to produce
2341       a high quality result. </td>
2342
2343  </tr>
2344
2345  <tr>
2346    <td>Barrel</td>
2347    <td>
2348       Given the four coefficients (A,B,C,D) as defined by <a
2349       href="http://wiki.panotools.org/Lens_correction_model" >Helmut
2350       Dersch</a>, perform a barrel or pin-cushion distortion appropriate to
2351       correct radial lens distortions.  That is in photographs, make straight
2352       lines straight again. <br/>
2353
2354       <p class="text-center">Arguments: <var>A   B   C</var>   [ <var>D</var>   [
2355       <var>X</var> , <var>Y</var> ] ] <br/>
2356       or <var>A<sub>x</sub> B<sub>x</sub> C<sub>x</sub> D<sub>x</sub>
2357       A<sub>y</sub> B<sub>y</sub> C<sub>y</sub> D<sub>y</sub></var>
2358       [ <var>X</var> , <var>Y</var> ] </p>
2359       So that it forms the function
2360       <p class="text-center">Rsrc = r * ( <var>A</var>*r<sup>3</sup> + <var>B</var>*r<sup>2</sup> +
2361                               <var>C</var>*r + <var>D</var> )</p>
2362
2363       Where <var>X</var>,<var>Y</var> is the optional center of the distortion
2364       (defaulting to the center of the image). <br/>
2365       The second form is typically used to distort images, rather than
2366       correct lens distortions. <br/>
2367       </td>
2368
2369  </tr>
2370
2371  <tr>
2372    <td>BarrelInverse</td>
2373    <td>
2374       This is very similar to 'Barrel' with the same set of
2375       arguments, and argument handling.  However it uses the inverse
2376       of the radial polynomial,
2377       so that it forms the function
2378       <p class="text-center">Rsrc = r / ( <var>A</var>*r<sup>3</sup> + <var>B</var>*r<sup>2</sup> +
2379                               <var>C</var>*r + <var>D</var> )</p>
2380       Note that this is not the reverse of the 'Barrel'
2381       distortion, just a different barrel-like radial distortion method.
2382
2383       </td>
2384  </tr>
2385
2386  <tr>
2387    <td>Shepards</td>
2388    <td>
2389       Distort the given list control points (any number) using an Inverse
2390       Squared Distance Interpolation Method (<a
2391       href="http://en.wikipedia.org/wiki/Shepard%27s_method" >Shepards
2392       Method</a>). The control points in effect do 'localized' displacement
2393       of the image around the given control point (preserving the look and
2394       the rotation of the area near the control points.  For best results
2395       extra control points should be added to 'lock' the positions of the
2396       corners, edges and other unchanging parts of the image, to prevent
2397       their movement. <br/>
2398
2399       The distortion has been likened to 'taffy pulling' using nails, or
2400       pins' stuck in a block of 'jelly' which is then moved to the new
2401       position, distorting the surface of the jelly. <br/>
2402
2403       Internally it is equivalent to generating a displacement map (see <a
2404       href="command-line-options.html#displace" >-displace</a>) for source image color look-up using
2405       the <a href="command-line-options.html#sparse-color" >-sparse-color</a> method of the same name.
2406
2407       </td>
2408  </tr>
2409
2410</table>
2411</div>
2412
2413<p>To print a complete list of distortion methods, use <a href="command-line-options.html#list">-list
2414distort</a>.</p>
2415
2416<p>Many of the above distortion methods such as '<code>Affine</code>',
2417'<code>Perspective</code>', and '<code>Shepards</code>' use a list control points
2418defining how these points in the given image should be distorted in the
2419destination image. Each set of four floating point values represent a source
2420image coordinate, followed immediately by the destination image coordinate.
2421This produces a list of values such as...</p>
2422<p class="text-center"><var>
2423      U<sub>1</sub>,V<sub>1</sub> X<sub>1</sub>,Y<sub>1</sub>
2424      U<sub>2</sub>,V<sub>2</sub> X<sub>2</sub>,Y<sub>2</sub>
2425      U<sub>3</sub>,V<sub>3</sub> X<sub>3</sub>,Y<sub>3</sub>
2426      ...
2427      U<sub>n</sub>,V<sub>n</sub> X<sub>n</sub>,Y<sub>n</sub>
2428</var></p>
2429<p>where <var>U,V</var> on the source image is mapped to <var>X,Y</var> on the
2430destination image. </p>
2431
2432<p>For example, to warp an image using '<code>perspective</code>' distortion,
2433needs a list of at least 4 sets of coordinates, or 16 numbers.  Here is the
2434perspective distortion of the built-in "rose:" image. Note how spaces were
2435used to group the 4 sets of coordinate pairs, to make it easier to read and
2436understand.</p>
2437
2438<pre class="highlight"><code>magick rose:  -virtual-pixel black \
2439  -distort Perspective '0,0,0,0  0,45,0,45  69,0,60,10  69,45,60,35' \
2440   rose_3d_rotated.gif"
2441</code></pre>
2442
2443<p>If more that the required number of coordinate pairs are given for
2444a distortion, the distortion method is 'least squares' fitted to produce the
2445best result for all the coordinate pairs given. If less than the ideal number
2446of points are given, the distort will generally fall back to a simpler form of
2447distortion that can handles the smaller number of coordinates (usually a linear
2448'<code>Affine</code>' distortion). </p>
2449
2450<p>By using more coordinates you can make use of image registration tool to
2451find matching coordinate pairs in overlapping images, so as to improve the
2452'fit' of the distortion. Of course a bad coordinate pair can also make the
2453'fit' worse. Caution is always advised. </p>
2454
2455<p>Colors are acquired from the source image according to a cylindrical
2456resampling <a href="command-line-options.html#filter" >-filter</a>, using a special technique known as
2457EWA resampling. This produces very high quality results, especially when
2458images become smaller (minified) in the output, which is very common when
2459using '<code>perspective</code>' distortion. For example here we view
2460a infinitely tiled 'plane' all the way to the horizon. </p>
2461
2462<pre class="highlight"><code>magick -size 90x90 pattern:checkerboard -normalize -virtual-pixel tile \
2463  -distort perspective  '0,0,5,45  89,0,45,46  0,89,0,89  89,89,89,89' \
2464   checks_tiled.jpg
2465</code></pre>
2466
2467<p>Note that a infinitely tiled perspective images involving the horizon can
2468be very slow, because of the number of pixels that are compressed to generate
2469each individual pixel close to the 'horizon'.  You can turn off EWA
2470resampling, by specifying the special <a href="command-line-options.html#filter" >-filter</a> setting of
2471'<code>point</code>' (recommended if you plan to use super-sampling instead).
2472</p>
2473
2474<p>If an image generates <i>invalid pixels</i>, such as the 'sky' in the last
2475example, <a href="command-line-options.html#distort" >-distort</a> will use the current <a
2476href="command-line-options.html#mattecolor" >-mattecolor</a> setting for these pixels. If you do not
2477what these pixels to be visible, set the color to match the rest of the
2478ground. </p>
2479
2480<p>The output image size will by default be the same as the input image.  This
2481means that if the part of the distorted image falls outside the viewed area of
2482the 'distorted space', those parts is clipped and lost.  However if you use
2483the plus form of the operator (<a href="command-line-options.html#distort" >+distort</a>) the operator
2484will attempt (if possible) to show the whole of the distorted image, while
2485retaining a correct 'virtual canvas' offset, for image layering. This offset
2486may need to be removed using <a href="command-line-options.html#repage" >+repage</a>, to remove if it
2487is unwanted. </p>
2488
2489<p>Setting <a href="command-line-options.html#verbose" >-verbose</a> setting, will cause <a
2490href="command-line-options.html#distort" >-distort</a> to attempt to output the internal coefficients,
2491and the <a href="command-line-options.html#fx" >-fx</a> equivalent to the distortion, for expert study,
2492and debugging purposes. This many not be available for all distorts. </p>
2493
2494<p>You can alternatively specify a special "<code><a href="command-line-options.html#define"
2495>-define</a> distort:viewport={geometry_string}</code>" setting which will
2496specify the size and the offset of the generated 'viewport' image of the
2497distorted image space.</p>
2498
2499<p>Setting a "<code><a href="command-line-options.html#define" >-define</a>
2500distort:scale=<var>scale_factor</var></code>" will scale the output image (viewport or
2501otherwise) by that factor without changing the viewed contents of the
2502distorted image. This can be used either for 'super-sampling' the image for
2503a higher quality result, or for panning and zooming around the image (with
2504appropriate viewport changes, or post-distort cropping and resizing). </p>
2505
2506<p>Setting "<code><a href="command-line-options.html#define" >-define</a> resample:verbose=1</code>"
2507will output the cylindrical filter lookup table created by the EWA (Elliptical
2508Weighted Average) resampling algorithm. Note this table uses a squared radius
2509lookup value. This is typically only used for debugging EWA resampling. </p>
2510
2511
2512<div style="margin: auto;">
2513  <h3><a class="anchor" id="distribute-cache"></a>-distribute-cache <var>port</var></h3>
2514</div>
2515
2516<p class="magick-description">Launch a distributed pixel cache server. </p>
2517
2518<div style="margin: auto;">
2519  <h3><a class="anchor" id="dither"></a>-dither <var>method</var></h3>
2520</div>
2521
2522<p class="magick-description">Apply a Riemersma or Floyd-Steinberg error diffusion dither to
2523images when general color reduction is applied via an option, or automagically
2524when saving to specific formats. This enabled by default.</p>
2525
2526<p>Dithering places two or more colors in neighboring pixels so that to the
2527eye a closer approximation of the images original color is reproduced. This
2528reduces the number of colors needed to reproduce the image but at the cost of
2529a lower level pattern of colors. Error diffusion dithers can use any set of
2530colors (generated or user defined) to an image.  </p>
2531
2532<p>Dithering is turned on by default, to turn it off use the plus form of the
2533setting, <a href="command-line-options.html#dither">+dither</a>. This will also render PostScript
2534without text or graphic aliasing. Disabling dithering often (but not always)
2535leads to faster process, a smaller number of colors, but more cartoon like
2536image coloring.  Generally resulting in 'color banding' effects in areas with
2537color gradients. </p>
2538
2539<p>The color reduction operators <a href="command-line-options.html#colors">-colors</a>, <a
2540href="command-line-options.html#monochrome">-monochrome</a>, <a href="command-line-options.html#remap ">-remap</a>, and <a
2541href="command-line-options.html#posterize">-posterize</a>, apply dithering to images using the reduced
2542color set they created. These operators are also used as part of automatic
2543color reduction when saving images to formats with limited color support, such
2544as <code>GIF:</code>, <code>XBM:</code>, and others, so dithering may also be used
2545in these cases. </p>
2546
2547<p>Alternatively you can use <a href="command-line-options.html#random-threshold">-random-threshold</a>
2548to generate purely random dither. Or use <a
2549href="command-line-options.html#ordered-dither">-ordered-dither</a> to apply threshold mapped dither
2550patterns, using uniform color maps, rather than specific color maps. </p>
2551<p>Use "<code><a href="command-line-options.html#define" >-define</a> dither:diffusion-amount=35%</code>, for example, to control the amount of Floyd-Steinberg dither.</p>
2552
2553
2554<div style="margin: auto;">
2555  <h3><a class="anchor" id="draw"></a>-draw <var>string</var></h3>
2556</div>
2557
2558<p class="magick-description">Annotate an image with one or more graphic primitives.</p>
2559
2560<p>Use this option to annotate or decorate an image with one or more graphic
2561primitives. The primitives include shapes, text, transformations, and pixel
2562operations.</p>
2563
2564<p>The shape primitives:</p>
2565
2566<div class="pre-scrollable highlight">
2567<dl class="row">
2568<dt class="col-md-4">point</dt><dd class="col-md-8">          x,y</dd>
2569<dt class="col-md-4">line</dt><dd class="col-md-8">           x0,y0 x1,y1</dd>
2570<dt class="col-md-4">rectangle</dt><dd class="col-md-8">      x0,y0 x1,y1</dd>
2571<dt class="col-md-4">roundRectangle</dt><dd class="col-md-8"> x0,y0 x1,y1 wc,hc</dd>
2572<dt class="col-md-4">arc</dt><dd class="col-md-8">            x0,y0 x1,y1 a0,a1</dd>
2573<dt class="col-md-4">ellipse</dt><dd class="col-md-8">        x0,y0 rx,ry a0,a1</dd>
2574<dt class="col-md-4">circle</dt><dd class="col-md-8">         x0,y0 x1,y1</dd>
2575<dt class="col-md-4">polyline</dt><dd class="col-md-8">       x0,y0  ...  xn,yn</dd>
2576<dt class="col-md-4">polygon</dt><dd class="col-md-8">        x0,y0  ...  xn,yn</dd>
2577<dt class="col-md-4">bezier</dt><dd class="col-md-8">         x0,y0  ...  xn,yn</dd>
2578<dt class="col-md-4">path</dt><dd class="col-md-8">specification  </dd>
2579<dt class="col-md-4">image</dt><dd class="col-md-8">          operator x0,y0 w,h filename</dd>
2580</dl>
2581</div>
2582
2583<p>The text primitive:</p>
2584
2585<dl class="row">
2586<dt class="col-md-4">text</dt><dd class="col-md-8">x0,y0 string</dd>
2587</dl>
2588<p>The text gravity primitive:</p>
2589
2590<dl class="row">
2591<dt class="col-md-4">gravity</dt><dd class="col-md-8">NorthWest, North, NorthEast, West, Center, East, SouthWest, South, or SouthEast</dd>
2592</dl>
2593
2594<p>The text gravity primitive only affects the placement of text and does not
2595interact with the other primitives.  It is equivalent to using the <a
2596href="command-line-options.html#gravity">-gravity</a> command-line option, except that it is limited in
2597scope to the <a href="command-line-options.html#draw">-draw</a> option in which it appears.</p>
2598
2599<p>The transformation primitives:</p>
2600
2601<div class="pre-scrollable highlight">
2602<dl class="row">
2603<dt class="col-md-4">rotate</dt><dd class="col-md-8">degrees</dd>
2604<dt class="col-md-4">translate</dt><dd class="col-md-8">dx,dy</dd>
2605<dt class="col-md-4">scale</dt><dd class="col-md-8">sx,sy</dd>
2606<dt class="col-md-4">skewX</dt><dd class="col-md-8">degrees</dd>
2607<dt class="col-md-4">skewY</dt><dd class="col-md-8">degrees</dd>
2608</dl>
2609</div>
2610
2611<p>The pixel operation primitives:</p>
2612
2613<div class="pre-scrollable highlight">
2614<dl class="row">
2615<dt class="col-md-4">color</dt><dd class="col-md-8">x0,y0 method</dd>
2616<dt class="col-md-4">matte</dt><dd class="col-md-8">x0,y0 method</dd>
2617</dl>
2618</div>
2619
2620<p>The shape primitives are drawn in the color specified by the preceding <a
2621href="command-line-options.html#fill">-fill</a> setting.  For unfilled shapes, use <a
2622href="command-line-options.html#fill">-fill none</a>.  You can optionally control the stroke (the
2623"outline" of a shape) with the <a href="command-line-options.html#stroke">-stroke</a> and <a
2624href="command-line-options.html#strokewidth">-strokewidth</a> settings.</p>
2625
2626<p>A <code>point</code> primitive is specified by a single <var>point</var> in the
2627pixel plane, that is, by an ordered pair of integer coordinates,
2628<var>x</var>,<var>y</var>. (As it involves only a single pixel, a <code>point</code>
2629primitive is not affected by <a href="command-line-options.html#stroke">-stroke</a> or <a
2630href="command-line-options.html#strokewidth">-strokewidth</a>.)</p>
2631
2632<p>A <code>line</code> primitive requires a start point and end point.</p>
2633
2634<p>A <code>rectangle</code> primitive is specified by the pair of points at the
2635upper left and lower right corners.</p>
2636
2637<p>A <code>roundRectangle</code> primitive takes the same corner points as
2638a <code>rectangle</code> followed by the width and height of the rounded corners
2639to be removed.</p>
2640
2641<p>The <code>circle</code> primitive makes a disk (filled) or circle (unfilled).
2642Give the center and any point on the perimeter (boundary).</p>
2643
2644<p>The <code>arc</code> primitive is used to inscribe an elliptical segment in
2645to a given rectangle. An <code>arc</code> requires the two corners used for
2646<code>rectangle</code> (see above) followed by the start and end angles of the
2647arc of the segment (e.g. 130,30 200,100 45,90). The start and end
2648points produced are then joined with a line segment and the resulting segment
2649of an ellipse is filled.</p>
2650
2651<p>Use <code>ellipse</code> to draw a partial (or whole) ellipse. Give the
2652center point, the horizontal and vertical "radii" (the <var>semi-axes</var> of
2653the ellipse) and start and end angles in degrees (e.g. 100,100 100,150
26540,360).</p>
2655
2656<p>The <code>polyline</code> and <code>polygon</code> primitives require three or
2657more points to define their perimeters. A <code>polyline</code> is simply
2658a <code>polygon</code> in which the final point is not stroked to the start
2659point. When unfilled, this is a <var>polygonal line</var>. If the <a
2660href="command-line-options.html#stroke">-stroke</a> setting is <code>none</code> (the default), then
2661a <code>polyline</code> is identical to a <code>polygon</code>.  </p>
2662
2663<p>A <var>coordinate</var> is a pair of integers separated by a space or
2664optional comma. </p>
2665
2666<p>As an example, to define a circle centered at 100,100 that extends to
2667150,150 use:</p>
2668
2669<pre class="highlight"><code>-draw 'circle 100,100 150,150'
2670</code></pre>
2671
2672<p>The <code>Bezier</code> primitive creates a spline curve and requires three
2673or points to define its shape. The first and last points are the
2674<var>knots</var> and these points are attained by the curve, while any
2675intermediate coordinates are <var>control points</var>. If two control points
2676are specified, the line between each end knot and its sequentially respective
2677control point determines the tangent direction of the curve at that end. If
2678one control point is specified, the lines from the end knots to the one
2679control point determines the tangent directions of the curve at each end. If
2680more than two control points are specified, then the additional control points
2681act in combination to determine the intermediate shape of the curve. In order
2682to draw complex curves, it is highly recommended either to use the
2683<code>path</code> primitive or to draw multiple four-point bezier segments with
2684the start and end knots of each successive segment repeated. For example:</p>
2685
2686<pre class="highlight"><code>-draw 'bezier 20,50 45,100 45,0 70,50'
2687-draw 'bezier 70,50 95,100 95,0 120,50'
2688</code></pre>
2689
2690<p>A <code>path</code> represents an outline of an object, defined in terms of
2691moveto (set a new current point), lineto (draw a straight line), curveto (draw
2692a Bezier curve), arc (elliptical or circular arc) and closepath (close the
2693current shape by drawing a line to the last moveto) elements. Compound paths
2694(i.e., a path with subpaths, each consisting of a single moveto followed by
2695one or more line or curve operations) are possible to allow effects such as
2696<var>donut holes</var> in objects. (See <a
2697href="http://www.w3.org/TR/SVG/paths.html">Paths</a>.)</p>
2698
2699<p>Use <code>image</code> to composite an image with another image. Follow the
2700image keyword with the composite operator, image location, image size, and
2701filename:</p>
2702
2703<pre class="highlight"><code>-draw 'image SrcOver 100,100 225,225 image.jpg'
2704</code></pre>
2705
2706<p>You can use 0,0 for the image size, which means to use the actual
2707dimensions found in the image header. Otherwise, it is scaled to the given
2708dimensions. See <a href="../www/compose.html">Alpha Compositing</a> for
2709a detailed discussion of alpha composition methods that are available. </p>
2710
2711<p>The "special augmented compose operators" such as "dissolve" that require
2712arguments cannot be used at present with the <code>-draw image</code> option.
2713 </p>
2714
2715<p>Use <code>text</code> to annotate an image with text. Follow the text
2716coordinates with a string. If the string has embedded spaces, enclose it in
2717single or double quotes.</p>
2718
2719<p>For example, the following annotates the image with <code>Works like
2720magick!</code> for an image titled <code>bird.miff</code>. </p>
2721
2722<pre class="highlight"><code>-draw "text 100,100 'Works like magick!'"</code></pre>
2723
2724<p>See the <a href="command-line-options.html#annotate">-annotate</a> option for another convenient way
2725to annotate an image with text.</p>
2726
2727<p>The <code>rotate</code> primitive rotates subsequent shape primitives and
2728text primitives about the origin of the main image:</p>
2729
2730<pre class="highlight"><code>-draw "rotate 45 text 10,10 'Works like magick!'"</code></pre>
2731
2732<p>The <code>translate</code> primitive translates subsequent shape and text
2733primitives.</p>
2734
2735<p>The <code>scale</code> primitive scales them.</p>
2736
2737<p>The <code>skewX</code> and <code>skewY</code> primitives skew them with respect
2738to the origin of the main image or the region.</p>
2739
2740<p>The transformations modify the current affine matrix, which is initialized
2741from the initial affine matrix defined by the <a href="command-line-options.html#affine">-affine</a>
2742option. Transformations are cumulative within the <a href="command-line-options.html#draw">-draw</a>
2743option. The initial affine matrix is not affected; that matrix is only changed
2744by the appearance of another <a href="command-line-options.html#affine">-affine</a> option. If another
2745<a href="command-line-options.html#draw">-draw</a> option appears, the current affine matrix is
2746reinitialized from the initial affine matrix.</p>
2747
2748<p>Use the <code>color</code> primitive to change the color of a pixel to the
2749fill color (see <a href="command-line-options.html#fill">-fill</a>). Follow the pixel coordinate with
2750a method:</p>
2751
2752<pre class="highlight"><code>point
2753replace
2754floodfill
2755filltoborder
2756reset
2757</code></pre>
2758
2759<p>Consider the target pixel as that specified by your coordinate. The
2760<code>point</code> method recolors the target pixel. The <code>replace</code>
2761method recolors any pixel that matches the color of the target pixel.
2762<code>Floodfill</code> recolors any pixel that matches the color of the target
2763pixel and is a neighbor, whereas <code>filltoborder</code> recolors any neighbor
2764pixel that is not the border color. Finally, <code>reset</code> recolors all
2765pixels.</p>
2766
2767<p>Use <code>matte</code> to the change the pixel matte value to transparent.
2768Follow the pixel coordinate with a method (see the <code>color</code> primitive
2769for a description of methods). The <code>point</code> method changes the matte
2770value of the target pixel. The <code>replace</code> method changes the matte
2771value of any pixel that matches the color of the target pixel.
2772<code>Floodfill</code> changes the matte value of any pixel that matches the
2773color of the target pixel and is a neighbor, whereas <code>filltoborder</code>
2774changes the matte value of any neighbor pixel that is not the border color (<a
2775href="command-line-options.html#bordercolor">-bordercolor</a>). Finally <code>reset</code> changes the
2776matte value of all pixels.</p>
2777
2778<p>You can set the primitive color, font, and font bounding box color with <a
2779href="command-line-options.html#fill">-fill</a>, <a href="command-line-options.html#font">-font</a>, and <a href="command-line-options.html#box">-box</a>
2780respectively.  Options are processed in command line order so be sure to use
2781these options <var>before</var> the <a href="command-line-options.html#draw">-draw</a> option.</p>
2782
2783<p>Strings that begin with a number must be quoted (e.g. use '1.png' rather
2784than 1.png).</p>
2785
2786<p>Drawing primitives conform to the <a href="magick-vector-graphics.html" >Magick
2787Vector Graphics</a> format.</p>
2788<p>Note, drawing requires an alpha channel.  If none is available, an all opaque alpha channel is implicitedly created.</p>
2789
2790
2791<div style="margin: auto;">
2792  <h3><a class="anchor" id="duplicate"></a>-duplicate <var>count,indexes</var></h3>
2793</div>
2794
2795<p class="magick-description">Duplicate an image one or more times.</p>
2796
2797<p>Specify the count and the image to duplicate by its index in the sequence.
2798The first image is index 0.  Negative indexes are relative to the end of the
2799sequence, for example, -1 represents the last image of the sequence.  Specify
2800a range of images with a dash (e.g. 0-4).  Separate indexes with a comma (e.g.
28010,2).  Use <code>+duplicate</code> to duplicate the last image in the current
2802image sequence.</p>
2803
2804<div style="margin: auto;">
2805  <h3><a class="anchor" id="edge"></a>-edge <var>radius</var></h3>
2806</div>
2807
2808<p class="magick-description">Detect edges within an image.</p>
2809
2810<div style="margin: auto;">
2811  <h3><a class="anchor" id="emboss"></a>-emboss <var>radius</var></h3>
2812</div>
2813
2814<p class="magick-description">Emboss an image.</p>
2815
2816<div style="margin: auto;">
2817  <h3><a class="anchor" id="encipher"></a>-encipher <var>filename</var></h3>
2818</div>
2819
2820<p class="magick-description">Encipher pixels for later deciphering by <a href="command-line-options.html#decipher">-decipher</a>.</p>
2821
2822<p>Get the passphrase from the file specified by <var>filename</var>.</p>
2823
2824<p>For more information, see the webpage, <a href="../www/cipher.html">ImageMagick: Encipher or
2825Decipher an Image</a>.</p>
2826
2827
2828
2829<div style="margin: auto;">
2830  <h3><a class="anchor" id="encoding"></a>-encoding <var>type</var></h3>
2831</div>
2832
2833<p class="magick-description">Specify the text encoding.</p>
2834
2835<p>Choose from</p>
2836
2837<pre class="highlight"><code>AdobeCustom     AdobeExpert
2838AdobeStandard   AppleRoman
2839BIG5            GB2312
2840Latin 2         None
2841SJIScode        Symbol
2842Unicode         Wansung
2843</code></pre>
2844
2845<div style="margin: auto;">
2846  <h3><a class="anchor" id="endian"></a>-endian <var>type</var></h3>
2847</div>
2848
2849<p class="magick-description">Specify endianness (<code>MSB</code> or <code>LSB</code>) of the image.</p>
2850
2851<p>To print a complete list of endian types, use the <a href="command-line-options.html#list">-list endian</a> option.</p>
2852
2853<p>Use <a href="command-line-options.html#endian">+endian</a> to revert to unspecified endianness.</p>
2854
2855
2856<div style="margin: auto;">
2857  <h3><a class="anchor" id="enhance"></a>-enhance</h3>
2858</div>
2859
2860<p class="magick-description">Apply a digital filter to enhance a noisy image.</p>
2861
2862
2863<div style="margin: auto;">
2864  <h3><a class="anchor" id="equalize"></a>-equalize</h3>
2865</div>
2866
2867<p class="magick-description">Perform histogram equalization on the image channel-by-channel.</p>
2868
2869<p>To perform histogram equalization on all channels in concert, transform the
2870image into some other color space, such as HSL, OHTA, YIQ or YUV, then
2871equalize the appropriate intensity-like channel, then convert back to RGB.</p>
2872
2873<p>For example using HSL, we have: ... <code>-colorspace HSL -channel lightness
2874-equalize -colorspace sRGB</code> ...</p>
2875
2876<p>For YIQ, YUV and OHTA use the red channel. For example, OHTA is a principal
2877components transformation that puts most of the information in the first
2878channel. Here we have ... <code>-colorspace OHTA -channel red -equalize
2879-colorspace sRGB</code> ...</p>
2880
2881<div style="margin: auto;">
2882  <h3><a class="anchor" id="evaluate"></a>-evaluate <var>operator value</var></h3>
2883</div>
2884
2885<p class="magick-description">Alter channel pixels by evaluating an arithmetic, relational, or logical expression.</p>
2886
2887<p>(See the <a href="command-line-options.html#function" >-function</a> operator for some
2888multi-parameter functions. See the <a href="command-line-options.html#fx" >-fx</a> operator if more
2889elaborate calculations are needed.)</p>
2890
2891<p>The behaviors of each <var>operator</var> are summarized in the
2892following list. For brevity, the numerical value of a "pixel" referred to
2893below is the value of the corresponding channel of that pixel, while
2894a "normalized pixel" is that number divided by the maximum
2895(installation-dependent) value <var>QuantumRange</var>. (If
2896normalized pixels are used, they are restored, following the other
2897calculations, to the full range by multiplying by <var>QuantumRange</var>.)</p>
2898
2899<div class="pre-scrollable highlight">
2900<table class="table table-sm table-hover">
2901  <col width="25%" />
2902  <col width="75%" />
2903  <thead>
2904  <tr>
2905  <th><var>operator</var></th>
2906  <th>Summary (see further below for details)</th>
2907  </tr>
2908  </thead>
2909  <tbody>
2910
2911    <tr><td>Abs </td>             <td>Add <var>value</var> to pixels and return absolute value. </td></tr>
2912    <tr><td>Add </td>             <td>Add <var>value</var> to pixels. </td></tr>
2913    <tr><td>AddModulus </td>      <td>Add <var>value</var> to pixels modulo <var>QuantumRange</var>.</td></tr>
2914    <tr><td>And  </td>            <td>Binary AND of pixels with <var>value</var>.</td></tr>
2915    <tr><td>Cos, Cosine </td>             <td>Apply cosine to pixels with frequency <var>value</var> with 50% bias added.</td></tr>
2916    <tr><td>Divide  </td>         <td>Divide pixels by <var>value</var>.</td></tr>
2917    <tr><td>Exp  </td>            <td>base-e exponential function</td></tr>
2918    <tr><td>Exponential  </td>            <td>base-e exponential function</td></tr>
2919    <tr><td>InverseLog  </td>            <td>Apply inverse scaled logarithm to normalized pixels.</td></tr>
2920    <tr><td>LeftShift </td>       <td>Shift the pixel values left by <var>value</var> bits (i.e., multiply pixels by 2<sup><var>value</var></sup>).</td></tr>
2921    <tr><td>Log  </td>            <td>Apply scaled logarithm to normalized pixels.</td></tr>
2922    <tr><td>Max  </td>            <td>Set pixels to maximum of <var>value</var> and current pixel <var>value</var> (i.e. set any pixels currently less than <var>value</var> to <var>value</var>).</td></tr>
2923    <tr><td>Mean  </td>            <td>Add the <var>value</var> and divide by 2.</td></tr>
2924    <tr><td>Median  </td>          <td>Choose the median value from an image sequence.</td></tr>
2925    <tr><td>Min  </td>            <td>Set pixels to minimum of <var>value</var> and current pixel <var>value</var> (i.e. set any pixels currently greater than <var>value</var> to <var>value</var>).</td></tr>
2926    <tr><td>Multiply </td>        <td>Multiply pixels by <var>value</var>.</td></tr>
2927    <tr><td>Or  </td>             <td>Binary OR of pixels with <var>value</var>.</td></tr>
2928    <tr><td>Pow </td>             <td>Raise normalized pixels to the power <var>value</var>.</td></tr>
2929    <tr><td>RightShift </td>      <td>Shift the pixel values right by <var>value</var> bits (i.e., divide pixels by 2<sup><var>value</var></sup>).</td></tr>
2930    <tr><td>RMS</td>            <td>Square the pixel and add the <var>value</var>.</td></tr>
2931    <tr><td>RootMeanSquare</td>            <td>Square the pixel and add the <var>value</var>.</td></tr>
2932    <tr><td>Set </td>             <td>Set pixel equal to <var>value</var>.</td></tr>
2933    <tr><td>Sin, Sine </td>             <td>Apply sine to pixels with frequency <var>value</var> with 50% bias added.</td></tr>
2934    <tr><td>Subtract </td>        <td>Subtract <var>value</var> from pixels.</td></tr>
2935    <tr><td>Xor </td>             <td>Binary XOR of pixels with <var>value.</var></td></tr>
2936
2937    <tr><td> </td><td> </td></tr>
2938
2939   <tr><td>Gaussian-noise</td><td> </td></tr>
2940   <tr><td>Impulse-noise</td><td> </td></tr>
2941   <tr><td>Laplacian-noise</td><td> </td></tr>
2942   <tr><td>Multiplicative-noise</td>      <td>(These are equivalent to the corresponding <a href="command-line-options.html#noise" >-noise</a> operators.)</td></tr>
2943   <tr><td>PoissonNoise</td><td> </td></tr>
2944   <tr><td>Uniform-noise</td><td> </td></tr>
2945
2946    <tr><td> </td><td> </td></tr>
2947
2948   <tr><td>Threshold </td>       <td>Threshold pixels larger than <var>value</var>.</td></tr>
2949   <tr><td>ThresholdBlack </td>  <td>Threshold pixels to zero values equal to or below <var>value</var>.</td></tr>
2950   <tr><td>ThresholdWhite </td>  <td>Threshold pixels to maximum values above <var>value</var>.  </td></tr>
2951 </tbody>
2952 </table>
2953</div>
2954
2955<p>The specified functions are applied only to each previously set <a
2956href="command-line-options.html#channel" >-channel</a> in the image. If necessary, the results of the
2957calculations are truncated (clipped) to fit in the interval [0, <var>QuantumRange</var>].  The transparency channel of the image is
2958represented as a 'alpha' values (0 = fully transparent), so, for example, a
2959<code>Divide</code> by 2 of the alpha channel will make the image
2960semi-transparent.  Append the percent symbol '<code>%</code>' to specify a value
2961as a percentage of the <var>QuantumRange</var>.</p>
2962
2963<p>To print a complete list of <a href="command-line-options.html#evaluate">-evaluate</a> operators, use
2964<a href="command-line-options.html#list">-list evaluate</a>.</p>
2965
2966<p>The results of the <code>Add</code>, <code>Subtract</code> and
2967<code>Multiply</code> methods can also be achieved using either the <a
2968href="command-line-options.html#level" >-level</a> or the <a href="command-line-options.html#level" >+level</a> operator, with
2969appropriate argument, to linearly modify the overall range of color values.
2970Please note, however, that <a href="command-line-options.html#level" >-level</a> treats transparency as
2971'matte' values (0 = opaque), while <a href="command-line-options.html#level" >-evaluate</a> works with
2972'alpha' values.</p>
2973
2974<p><code>AddModulus</code> has been added as of ImageMagick 6.4.8-4 and provides
2975addition modulo the <var>QuantumRange</var>. It is therefore
2976equivalent to <code>Add</code> unless the resulting pixel value is outside the
2977interval [0, <var>QuantumRange</var>]. </p>
2978
2979<p><code>Exp or Exponential</code> has been added as of ImageMagick 6.6.5-1 and
2980works on normalized pixel values. The <var>value</var> used with
2981<code>Exp</code> should be negative so as to produce a decaying exponential
2982function. Non-negative values will always produce results larger unity and
2983thus outside the interval [0, <var>QuantumRange</var>]. The
2984formula is expressed below. </p>
2985
2986<p class="text-center">
2987exp(<var>value</var> × <b><var>u</var></b>)
2988</p>
2989
2990<p> If the input image is squared, for example, using <a href="command-line-options.html#-function"
2991>-function polynomial "2 0 0"</a>, then a decaying Gaussian function will be
2992the result.</p>
2993
2994<p><code>Log</code> has been added as of ImageMagick 6.4.2-1 and works on
2995normalized pixel values. This a <var>scaled</var> log function. The <var>value</var> used with <code>Log</code> provides a <var>scaling
2996factor</var> that adjusts the curvature in the graph of the log function. The
2997formula applied to a normalized value <b><var>u</var></b> is below. </p>
2998
2999<p class="text-center">
3000log(<var>value</var> × <b><var>u</var></b> + 1) / log(<var>value</var> + 1)
3001</p>
3002
3003<p><code>Pow</code> has been added as of ImageMagick 6.4.1-9, and works on
3004normalized pixel values. Note that <code>Pow</code> is related to the <a
3005href="command-line-options.html#gamma" >-gamma</a> operator. For example, <b>-gamma 2</b> is equivalent
3006to <b>-evaluate pow 0.5</b>, i.e., a 'square root' function. The value used
3007with <a href="command-line-options.html#gamma" >-gamma</a> is simply the reciprocal of the value used
3008with <code>Pow</code>.</p>
3009
3010<p><code>Cosine</code> and <code>Sine</code> was added as of IM v6.4.8-8 and
3011converts the image values into a value according to a (co)sine wave function.
3012The  synonyms <code>Cos</code> and <code>Sin</code> may also be used.  The output
3013is biased 50% and normalized by 50% so as to fit in the respective color value
3014range.  The <var>value</var> scaling of the <var>period</var> of the
3015function (its frequency), and thus determines the number of 'waves' that will
3016be generated over the input color range.  For example, if the <var>value</var> is 1, the effective period is simply the <var>QuantumRange</var>; but if the <var>value</var> is 2,
3017then the effective period is the <var>half</var> the <var>QuantumRange</var>.</p>
3018
3019<p class="text-center">
30200.5 + 0.5 × cos(2 π <b><var>u</var></b> × <var>value</var>).
3021</p>
3022
3023<p>See also the <a href="command-line-options.html#function" >-function</a> operator, which is a
3024multi-value version of evaluate. </p>
3025
3026<div style="margin: auto;">
3027  <h3><a class="anchor" id="evaluate-sequence"></a>-evaluate-sequence <var>operator</var></h3>
3028</div>
3029
3030<p class="magick-description">Alter channel pixels by evaluating an arithmetic, relational, or logical expression over a sequence of images.  Ensure all the images in the sequence are in the same colorspace, otherwise you may get unexpected results, e.g. add <a href="command-line-options.html#colorspace" >-colorspace sRGB</a> to your command-line.</p>
3031
3032<p>To print a complete list of <a
3033href="command-line-options.html#evaluate-sequence">-evaluate-sequence</a> operators, use <a
3034href="command-line-options.html#list">-list evaluate</a>.</p>
3035
3036<div style="margin: auto;">
3037  <h3><a class="anchor" id="extent"></a>-extent <var>geometry</var></h3>
3038</div>
3039
3040<p class="magick-description">Set the image size and offset.</p>
3041
3042<p>If the image is enlarged, unfilled areas are set to the background color.
3043To position the image, use offsets in the <var>geometry</var>
3044specification or precede with a <a href="command-line-options.html#gravity">-gravity</a> setting.  To
3045specify how to compose the image with the background, use <a href="command-line-options.html#compose"
3046>-compose</a>.</p>
3047
3048<p>This command reduces or expands a JPEG image to fit on an 800x600
3049display.  If the aspect ratio of the input image isn't exactly 4:3, then the
3050image is centered on an 800x600 black canvas: </p>
3051
3052<pre class="highlight"><code>magick input.jpg -resize 800x600 -background black -compose Copy \
3053  -gravity center -extent 800x600 -quality 92 output.jpg
3054</code></pre>
3055
3056<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
3057
3058<div style="margin: auto;">
3059  <h3><a class="anchor" id="extract"></a>-extract <var>geometry</var></h3>
3060</div>
3061
3062<p class="magick-description">Extract the specified area from image.</p>
3063
3064<p>This option is most useful for extracting a subregion of a very large raw
3065image.  Note that these two commands are equivalent:</p>
3066
3067<pre class="highlight"><code>magick -size 16000x16000 -depth 8 -extract 640x480+1280+960 \
3068  image.rgb image.png",
3069convert -size 16000x16000 -depth 8 'image.rgb[640x480+1280+960]' \
3070  image.rgb image.png"
3071</code></pre>
3072
3073<p>If you omit the offsets, as in</p>
3074
3075<pre class="highlight"><code>magick -size 16000x16000 -depth 8 -extract 640x480 \
3076  image.rgb image.png
3077</code></pre>
3078
3079<p>the image is <var>resized</var> to the specified dimensions instead,
3080equivalent to:</p>
3081
3082<pre class="highlight"><code>magick -size 16000x16000 -depth 8 -resize 640x480 image.rgb image.png
3083</code></pre>
3084
3085<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
3086
3087<div style="margin: auto;">
3088  <h3><a class="anchor" id="family"></a>-family <var>fontFamily</var></h3>
3089</div>
3090
3091<p class="magick-description">Set a font family for text.</p>
3092
3093<p>This setting suggests a font family that ImageMagick should try to use for
3094rendering text. If the family can be found it is used; if not, a default font
3095(e.g., "Arial") or a family known to be similar is substituted (e.g.,
3096"Courier" might be used if "System" is requested but not found). Note, the family can be a CSS-style font list.</p>
3097
3098<p>For other settings that affect fonts, see the options
3099<a href="../www/command-line-options.html#font">-font</a>,
3100<a href="../www/command-line-options.html#pointsize">-pointsize</a>,
3101<a href="../www/command-line-options.html#stretch">-stretch</a>,
3102<a href="../www/command-line-options.html#style">-style</a>,
3103and <a href="../www/command-line-options.html#weight">-weight</a>.  </p>
3104
3105<div style="margin: auto;">
3106  <h3><a class="anchor" id="features"></a>-features <var>distance</var></h3>
3107</div>
3108
3109<p class="magick-description">Display (co-occurrence matrix) texture measure features for each channel in the image in each of four directions (horizontal, vertical, left and right diagonals) for the specified distance.</p>
3110
3111<pre class="highlight"><code>Angular Second Moment       Sum Entropy
3112Contrast                    Entropy
3113Correlation                 Difference Variance
3114Sum of Squares Variance     Difference Entropy
3115Inverse Difference Moment   Information Measure of Correlation 1
3116Sum Average                 Information Measure of Correlation 2
3117Sum Variance                Maximum Correlation Coefficient
3118</code></pre>
3119
3120<div style="margin: auto;">
3121  <h3><a class="anchor" id="fft"></a>-fft</h3>
3122</div>
3123
3124<p class="magick-description">Implements the forward discrete Fourier transform (DFT).</p>
3125
3126<p>This option is new as of ImageMagick 6.5.4-3 (and now working for Windows
3127users in ImageMagick 6.6.0-9). It transforms an image from the normal
3128(spatial) domain to the frequency domain. In the frequency domain, an image is
3129represented as a superposition of complex sinusoidal waves of varying
3130amplitudes. The image x and y coordinates are the possible frequencies along
3131the x and y directions, respectively, and the pixel intensity values are
3132complex numbers that correspond to the sinusoidal wave amplitudes. See for
3133example, <a href="http://en.wikipedia.org/wiki/Fourier_transform">Fourier
3134Transform</a>, <a href="http://en.wikipedia.org/wiki/DFT">Discrete Fourier
3135Transform</a> and <a href="http://en.wikipedia.org/wiki/FFT">Fast Fourier
3136Transform</a>.</p>
3137
3138<p>A single image name is provided as output for this option. However, the
3139output result will have two components. It is either a two-frame image or two
3140separate images, depending upon whether the image format specified supports
3141multi-frame images. The reason that we get a dual output result is because the
3142frequency domain represents an image using complex numbers, which cannot be
3143visualized directly. Therefore, the complex values are automagically separated
3144into a two-component image representation. The first component is the
3145magnitude of the complex number and the second is the phase of the complex
3146number. See for example, <a
3147href="http://en.wikipedia.org/wiki/Complex_numbers">Complex Numbers</a>.</p>
3148
3149<p>The magnitude and phase component images must be specified using image
3150formats that do not limit the color or compress the image. Thus, MIFF, TIF,
3151PFM, EXR and PNG are the recommended image formats to use. All of these
3152formats, except PNG support multi-frame images. So for example,</p>
3153
3154<pre class="highlight"><code>magick image.png -fft fft_image.miff
3155</code></pre>
3156
3157<p>generates a magnitude image as <code>fft_image.miff[0]</code> and a phase
3158image as <code>fft_image.miff[1]</code>. Similarly,</p>
3159
3160<pre class="highlight"><code>magick image.png -fft fft_image.png
3161</code></pre>
3162
3163<p>generates a magnitude image as <code>fft_image-0.png</code> and a phase image
3164as <code>fft_image-1.png</code>. If you prefer this representation, then you can
3165force any of the other formats to produce two output images by including <a
3166href="command-line-options.html#adjoin">+adjoin</a> following -fft in the command line.</p>
3167
3168<p>The input image can be any size, but if not square and even-dimensioned, it
3169is padded automagically to the larger of the width or height of the input
3170image and to an even number of pixels. The padding will occur at the bottom
3171and/or right sides of the input image. The resulting output magnitude and
3172phase images is square at this size. The kind of padding relies on the <a
3173href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting.</p>
3174
3175<p>Both output components will have dynamic ranges that fit within
3176[0, <var>QuantumRange</var>], so that HDRI need not be enabled.
3177Phase values nominally range from 0 to 2*π, but is scaled to span the full
3178dynamic range.  (The first few releases had non-HDRI scaled but HDRI not
3179scaled). The magnitude image is not scaled and thus generally will contain
3180very small values. As such, the image normally will appear totally black. In
3181order to view any detail, the magnitude image typically is enhanced with a log
3182function into what is usually called the spectrum. A log function is used to
3183enhance the darker values more in comparison to the lighter values. This can
3184be done, for example, as follows:</p>
3185
3186<pre class="highlight"><code>magick fft_image.miff[0] -contrast-stretch 0 \
3187  -evaluate log 1000 fft_image_spectrum.png"
3188</code></pre>
3189
3190<p>where either <a href="command-line-options.html#contrast-stretch">-contrast-stretch</a> 0 or <a
3191href="command-line-options.html#auto-level">-auto-level</a> is used to scale the image to full dynamic
3192range, first. The argument to the <a href="command-line-options.html#evaluate">-evaluate</a> log
3193typically is specified between 100 and 10,000, depending upon the amount of
3194detail that one wants to bring out in the spectrum. Larger values produce more
3195visible detail. Too much detail, however, may hide the important features.</p>
3196
3197<p>The <a href="http://www.fftw.org/">FFTW</a> delegate library is required to
3198use <a href="command-line-options.html#fft">-fft</a>.</p>
3199
3200<p>Use <a href="command-line-options.html#fft">+fft</a> to produce two output images that are the real
3201and imaginary components of the complex valued Fourier transform.</p>
3202
3203<p>However, as the real and imaginary components can contain negative values,
3204this requires that IM be configured with HDRI enabled. In this case, you must
3205use either MIFF, TIF, PFM or MPC formats for the real and imaginary component
3206results, since they are formats that preserve both negative and fractional
3207values without clipping them or truncating the fractional part. With either
3208MIFF or TIF, one should add <code>-define quantum:format=32</code>, to allow those image
3209types to work properly in HDRI mode without clipping.</p>
3210
3211<p>The real and imaginary component images resulting from <a
3212href="command-line-options.html#fft">+fft</a> are also square, even dimensioned images due to the same
3213padding that was discussed above for the magnitude and phase component
3214images.</p>
3215
3216<p>See the discussion on HDRI implementations of ImageMagick on the page <a
3217href="high-dynamic-range.html" >High Dynamic-Range Images</a>. For more
3218about HDRI go the ImageMagick <a
3219href="https://legacy.imagemagick.org/Usage/basics/#hdri" >Usage</a> pages, <a
3220href="http://www.fmwconcepts.com/imagemagick/fourier_transforms/fourier.html"
3221>Fred's Fourier Processing With ImageMagick page</a> or this <a
3222 href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging" >Wikipedia</a>
3223 entry.  </p>
3224
3225<p>By default the FFT is normalized (and the IFT is not). Use "<code><a href="command-line-options.html#define" >-define</a> fourier:normalize=forward</code> to explicitly normalize the FFT and unnormalize the IFT.</p>
3226
3227
3228<div style="margin: auto;">
3229  <h3><a class="anchor" id="fill"></a>-fill <var>color</var></h3>
3230</div>
3231
3232<p class="magick-description">Color to use when filling a graphic primitive.</p>
3233
3234<p>This option accepts a color name, a hex color, or a numerical RGB, RGBA,
3235HSL, HSLA, CMYK, or CMYKA specification.  See <a href="../www/color.html" >Color Names</a> for
3236a description of how to properly specify the color argument.</p>
3237
3238<p>Enclose the color specification in quotation marks to prevent the "#" or
3239the parentheses from being interpreted by your shell.</p>
3240
3241<p>For example,</p>
3242
3243<pre class="highlight"><code>-fill blue
3244-fill "#ddddff"
3245-fill "rgb(255,255,255)"
3246</code></pre>
3247
3248<p>See <a href="command-line-options.html#draw">-draw</a> for further details.</p>
3249
3250<p>To print a complete list of color names, use the <a href="command-line-options.html#list">-list color</a> option.</p>
3251
3252<div style="margin: auto;">
3253  <h3><a class="anchor" id="filter"></a>-filter <var>type</var></h3>
3254</div>
3255
3256<p class="magick-description">Use this <var>type</var> of filter when resizing or distorting an image.</p>
3257
3258<p>Use this option to affect the resizing operation of an image during
3259operations such as <a href="command-line-options.html#resize">-resize</a> and <a href="command-line-options.html#distort"
3260>-distort</a>. For example you can use a simple resize filter such as:</p>
3261
3262<pre class="highlight"><code>Point       Hermite       Cubic
3263Box         Gaussian      Catrom
3264Triangle    Quadratic     Mitchell
3265CubicSpline
3266</code></pre>
3267
3268<p>Use <code>-define filter:lobes={2,3,4}</code> to specify the support size for filtering for the <code>CubicSpline</code> filter.</p>
3269
3270<p>The <code>Bessel</code> and <code>Sinc</code> filter is also provided (as well
3271as a faster <code>SincFast</code> equivalent form).  However these filters are
3272generally useless on their own as they are infinite filters that are being
3273clipped to the filters support size. Their direct use is not recommended
3274except via expert settings (see below). </p>
3275
3276<p>Instead these special filter functions are typically windowed by a windowing
3277function that the <a href="command-line-options.html#filter" >-filter</a> setting defines.   That is
3278using these functions will define a 'Windowed' filter, appropriate to the
3279operator involved.  Windowed filters include: </p>
3280
3281<pre class="highlight"><code>Lanczos       Hamming       Parzen
3282Blackman      Kaiser        Welsh
3283Hanning       Bartlett      Bohman
3284</code></pre>
3285
3286<p>Also one special self-windowing filter is also provided
3287<code>Lagrange</code>, which will automagically re-adjust its function depending
3288on the current 'support' or 'lobes' expert settings (see below).</p>
3289
3290<p>If you do not select a filter with this option, the filter defaults to
3291<code>Mitchell</code> for a colormapped image, an image with a matte channel, or
3292if the image is enlarged.  Otherwise the filter default to
3293<code>Lanczos</code>.</p>
3294
3295<p>To print a complete list of resize filters, use the <a href="command-line-options.html#list">-list
3296filter</a> option.</p>
3297
3298<p>You can modify how the filter behaves as it scales your image through the
3299use of these expert settings (see also <a href="command-line-options.html#define" >-define</a> and <a
3300href="command-line-options.html#set" >-set</a>):-</p>
3301
3302<div class="pre-scrollable highlight">
3303<table class="table table-sm table-hover">
3304  <tr>
3305    <td>-define filter:blur=<var>factor</var></td>
3306    <td>Scale the X axis of the filter (and its window). Use &gt; 1.0 for
3307    blurry or &lt; 1.0 for sharp. This should only be used with Gaussian and
3308    Gaussian-like filters simple filters, or you may not get the expected
3309    results. </td>
3310  </tr>
3311
3312  <tr>
3313    <td>-define filter:support=<var>radius</var></td>
3314    <td>Set the filter support radius. Defines how large the filter should be and
3315    thus directly defines how slow the filtered resampling process is. All
3316    filters have a default 'preferred' support size. Some filters like
3317    <code>Lagrange</code> and windowed filters adjust themselves depending on
3318    this value.  With simple filters this value either does nothing (but slow
3319    the resampling), or will clip the filter function in a detrimental way.
3320    </td>
3321  </tr>
3322
3323  <tr>
3324    <td>-define filter:lobes=<var>count</var></td>
3325    <td>Set the number of lobes to use for the Sinc/Bessel filter. This an
3326    alternative way of specifying the 'support' range of the filter, that is
3327    designed to be more suited to windowed filters, especially when used for
3328    image distorts.</td>
3329  </tr>
3330
3331  <tr>
3332    <td>-define filter:sigma=<var>value</var></td>
3333    <td>The 'sigma' value used to define the <code>Gaussian</code> filter.  Default
3334    sigma value is '<code>0.5</code>'.  It only affects <code>Gaussian</code> but
3335    does not shrink (but may enlarge) the filter's 'support'.  It can be used
3336    to generate very small blurs but without the filter 'missing' pixels due
3337    to using a small support setting. A larger value of '<code>0.707</code>'
3338    (a value of '1/sqrt(2)') is another common setting. </td>
3339  </tr>
3340
3341  <tr>
3342    <td>-define filter:b=<var>b-spline_factor</var></td>
3343  </tr>
3344
3345  <tr>
3346    <td>-define filter:c=<var>keys_alpha_factor</var></td>
3347    <td>Redefine the values used for cubic filters such as <code>Cubic</code>,
3348    <code>Catrom</code>, <code>Mitchel</code>, and <code>Hermite</code>, as well as
3349    the <code>Parzen</code> cubic windowing function. If only one of the values
3350    are defined, the other is set so as to generate a 'Cubic-Keys' filter.
3351    The values meaning was defined by a research paper by
3352    Mitchell-Netravali.</td>
3353  </tr>
3354
3355  <tr>
3356    <td>-define filter:kaiser-beta=<var>value</var></td>
3357    <td>The 'alpha' value used to as part of the Kaiser Windowing function.
3358    Default value is '6.5'.  It only affects Kaiser windowing function, and
3359    does not affect any other attributes.
3360    Before ImageMagick v6.7.6-10, this option was known as "filter:alpha", (an
3361    inheritance from the very old "zoom" program). It was changed to bring the
3362    function in line with more modern academic research usage, and better
3363    assign it be more definitive.  </td>
3364  </tr>
3365
3366  <tr>
3367    <td>-define filter:kaiser-alpha=<var>value</var></td>
3368    <td>This value when multiplied by 'PI' is equivalent to "kaiser-beta", and
3369    will override that setting.  It only affects Kaiser windowing function,
3370    and does not affect any other attributes. </td>
3371  </tr>
3372
3373  <tr>
3374    <td>-define filter:filter=<var>filter_function</var></td>
3375    <td>Use this function directly as the weighting filter.  This will allow
3376    you to directly use a windowing function such as <code>Blackman</code>,
3377    as a resampling filter, rather than as its normal usage as a windowing
3378    function.  If defined, no windowing function also defined, the window function is set
3379    to <code>Box</code>). Directly specifying <code>Sinc</code> or <code>Jinc</code>
3380    as a filter will also do this. </td>
3381  </tr>
3382
3383  <tr>
3384    <td>-define filter:window=<var>filter_function</var></td>
3385    <td>The IIR (infinite impulse response) filters <code>Sinc</code> and
3386    <code>Jinc</code> are windowed (brought down to zero over the defined
3387    support range) with the given filter. This allows you to specify a filter
3388    function to be used as a windowing function for these IIR filters.
3389    Many of the defined filters are actually windowing functions for these IIR
3390    filters.  A typical choices is <code>Box</code>, (which effectively turns
3391    off the windowing function).  </td>
3392  </tr>
3393
3394  <tr>
3395    <td>-define filter:win-support=<var>radius</var></td>
3396    <td>Scale windowing function to this size instead.  This causes the windowing
3397    (or self-windowing Lagrange filter) to act is if the support window is
3398    larger than what is actually supplied to the calling operator.  The filter
3399    however is still clipped to the real support size given.  If unset this
3400    will equal the normal filter support size. </td>
3401  </tr>
3402
3403  <tr>
3404    <td>-define filter:verbose=<var>1</var></td>
3405    <td>This causes IM to print information on the final internal filter
3406    selection to standard output.  This includes a commented header on the
3407    filter settings being used, and data allowing the filter weights to be
3408    easily graphed.  Note however that some filters are internally defined in terms of other filters.  The <code>Lanczos</code> filter for example is defined in terms of
3409    a <code>SincFast</code> windowed <code>SincFast</code> filter, while
3410    <code>Mitchell</code> is defined as a general <code>Cubic</code> family filter
3411    with specific 'B' and 'C' settings. </td>
3412  </tr>
3413
3414</table>
3415</div>
3416
3417<p>For example, to get a 8 lobe jinc windowed sinc filter (Genseng filter?):</p>
3418
3419<pre class="highlight"><code>magick image.png \
3420  -filter sinc \
3421  -set filter:window=jinc \
3422  -set filter:lobes=8 \
3423  -resize 150% image.jpg"
3424</code></pre>
3425
3426<p>Or a raw un-windowed Sinc filter with 4 lobes:</p>
3427
3428<pre class="highlight"><code>magick image.png \
3429  -set filter:filter=sinc \
3430  -set filter:lobes=4 \
3431  -resize 150% image.jpg"
3432</code></pre>
3433
3434<p>To extract the data for a raw windowing function, combine it with
3435a '<code>Box</code>' filter.  For example the '<code>Welch</code> parabolic
3436windowing function. </p>
3437
3438<pre class="highlight"><code>magick null: -define filter:filter=Box \
3439  -define filter:window=Welch \
3440  -define filter:support=1.0 \
3441  -define filter:verbose=1 \
3442  -resize 2 null: > window_welch.dat
3443gnuplot
3444  set grid
3445  plot \"window_welch.dat\" with lines
3446</code></pre>
3447
3448<p>Note that the use of expert options is provided for image processing experts
3449who have studied and understand how resize filters work. Without this
3450knowledge, and an understanding of the definition of the actual filters
3451involved, using expert settings are more likely to be detrimental to your image
3452resizing.</p>
3453
3454
3455<div style="margin: auto;">
3456  <h3><a class="anchor" id="flatten"></a>-flatten</h3>
3457</div>
3458
3459<p class="magick-description">This is a simple alias for the <a href="command-line-options.html#layers" >-layers</a> method "flatten".</p>
3460
3461
3462<div style="margin: auto;">
3463  <h3><a class="anchor" id="flip"></a>-flip</h3>
3464</div>
3465
3466<p class="magick-description">Create a <var>mirror image</var></p>
3467
3468<p>reflect the scanlines in the vertical direction. The image will be mirrored
3469upside-down. </p>
3470
3471
3472<div style="margin: auto;">
3473  <h3><a class="anchor" id="floodfill"></a>-floodfill {<var>+-</var>}<var>x</var>{<var>+-</var>}<var>y</var> <var>color</var></h3>
3474</div>
3475
3476<p class="magick-description">Floodfill the image with color at the specified offset.</p>
3477
3478<p>Flood fill starts from the given 'seed point' which is not gravity affected.
3479Any color that matches within <a href="command-line-options.html#fuzz" >-fuzz</a> color distance of the
3480given <var>color</var>  argument, connected to that 'seed point'
3481will be replaced with the current <a href="command-line-options.html#fill" >-fill</a> color. </p>
3482
3483<p>Note that if the pixel at the 'seed point' does not itself match the given
3484<var>color</var> (according to <a href="command-line-options.html#fuzz" >-fuzz</a>), then no
3485action will be taken. </p>
3486
3487<p>This operator works more like the <a href="command-line-options.html#opaque" >-opaque</a> option, than
3488a more general flood fill that reads the matching color directly at the 'seed
3489point'. For this form of flood fill, look at <a href="command-line-options.html#draw" >-draw</a>  and
3490its 'color floodfill' drawing method.  </p>
3491
3492
3493<div style="margin: auto;">
3494  <h3><a class="anchor" id="flop"></a>-flop</h3>
3495</div>
3496
3497<p class="magick-description">Create a <var>mirror image</var>.</p>
3498
3499<p>Reflect the scanlines in the horizontal direction, just like the image in
3500a vertical mirror. </p>
3501
3502
3503<div style="margin: auto;">
3504  <h3><a class="anchor" id="font"></a>-font <var>name</var></h3>
3505</div>
3506
3507<p class="magick-description">Set the font to use when annotating images with text, or creating labels.</p>
3508
3509<p>To print a complete list of fonts, use the <a href="command-line-options.html#list">-list font</a>
3510option (for versions prior to 6.3.6, use 'type' instead of 'font').</p>
3511
3512<p>In addition to the fonts specified by the above pre-defined list, you can
3513also specify a font from a specific source.  For example <code>Arial.ttf</code>
3514is a TrueType font file, <code>ps:helvetica</code> is PostScript font, and
3515<code>x:fixed</code> is X11 font.</p>
3516
3517<p>For other settings that affect fonts, see the options <a
3518href="command-line-options.html#family">-family</a>, <a href="command-line-options.html#stretch">-stretch</a>, <a
3519href="command-line-options.html#style">-style</a>, and <a href="command-line-options.html#weight">-weight</a>. </p>
3520
3521
3522<div style="margin: auto;">
3523  <h3><a class="anchor" id="foreground"></a>-foreground <var>color</var></h3>
3524</div>
3525
3526<p class="magick-description">Define the foreground color for menus.", "display</p>
3527
3528<p>The color is specified using the format described under the <a
3529href="command-line-options.html#fill">-fill</a> option.</p>
3530
3531<p>The default foreground color is black.</p>
3532
3533<div style="margin: auto;">
3534  <h3><a class="anchor" id="format"></a>-format <var>type</var></h3>
3535</div>
3536
3537<p class="magick-description">The image format type.</p>
3538
3539<p>When used with the <code>mogrify</code> utility, this option converts any
3540image to the image <a href="formats.html">format</a> you specify.
3541For a list of image format types supported by ImageMagick, use <a
3542href="command-line-options.html#list">-list format</a>.</p>
3543
3544<p>By default the file is written to its original name. However, if the
3545filename extension matches a supported format, the extension is replaced with
3546the image format type specified with <a href="command-line-options.html#format">-format</a>. For
3547example, if you specify <var>tiff</var> as the format type and the
3548input image filename is <var>image.gif</var>, the output image
3549filename becomes <var>image.tiff</var>.</p>
3550
3551<div style="margin: auto;">
3552  <h3><a class="anchor" id="format_identify_"></a>-format <var>string</var></h3>
3553</div>
3554
3555<p class="magick-description">Output formatted image characteristics.</p>
3556
3557<p>See <a href="../www/escape.html">Format and Print Image
3558Properties</a> for an explanation on how to specify the argument to this
3559option.</p>
3560
3561<div style="margin: auto;">
3562  <h3><a class="anchor" id="frame"></a>-frame <var>geometry</var></h3>
3563</div>
3564
3565<p class="magick-description">Surround the image with a border or beveled frame.</p>
3566
3567<p>The color of the border is specified with the <a href="command-line-options.html#mattecolor"
3568>-mattecolor</a> command line option. </p>
3569
3570<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. The <var>size</var> portion of the <var>geometry</var> argument indicates the amount of extra width and
3571height that is added to the dimensions of the image. If no offsets are given
3572in the <var>geometry</var> argument, then the border added is
3573a solid color.  Offsets <var>x</var> and <var>y</var>, if present, specify that
3574the width and height of the border is partitioned to form an outer bevel of
3575thickness <var>x</var> pixels and an inner bevel of thickness
3576<var>y</var> pixels. Negative offsets make no sense as frame arguments.
3577</p>
3578
3579<p>The <a href="command-line-options.html#frame">-frame</a> option is affected by the current <a
3580href="command-line-options.html#compose">-compose</a> setting and assumes that this is using the default
3581'<code>Over</code>' composition method.  It generates an image of the appropriate
3582size with the current <a href="command-line-options.html#bordercolor">-bordercolor</a> setting, and then
3583draws the frame of four distinct colors close to the current <a
3584href="command-line-options.html#mattecolor">-mattecolor</a>.  The original image is then overlaid onto
3585center of this image.  This means that with the default compose method of
3586'<code>Over</code>' any transparent parts may be replaced by the current <a
3587href="command-line-options.html#bordercolor">-bordercolor</a> setting.</p>
3588
3589<p>The image composition is not
3590affected by the <a href="command-line-options.html#gravity">-gravity</a> option.</p>
3591
3592
3593<div style="margin: auto;">
3594  <h3><a class="anchor" id="frame_import_"></a>-frame</h3>
3595</div>
3596
3597<p class="magick-description">Include the X window frame in the imported image. </p>
3598<div style="margin: auto;">
3599  <h3><a class="anchor" id="function"></a>-function <var>function</var> <var>parameters</var></h3>
3600</div>
3601
3602<p class="magick-description">Apply a function to channel values.</p>
3603
3604<p>This operator performs calculations based on the given arguments to modify
3605each of the color values for each previously set <a
3606href="command-line-options.html#channel">-channel</a> in the image. See <a
3607href="command-line-options.html#evaluate">-evaluate</a> for details concerning how the results of the
3608calculations are handled.</p>
3609
3610<p>This is can be considered a multi-argument version of the <a
3611href="command-line-options.html#evaluate">-evaluate</a> operator. (Added in
3612ImageMagick 6.4.8−8.)</p>
3613
3614<p>Here,  <var>parameters</var> is a comma-separated list of
3615numerical values. The number of values varies depending on which <var>function</var> is selected. Choose the <var>function</var> from:</p>
3616
3617<pre class="highlight"><code>Polynomial
3618Sinusoid
3619Arcsin
3620Arctan
3621</code></pre>
3622
3623<p>To print a complete list of <a href="command-line-options.html#function">-function</a> operators,
3624use <a href="command-line-options.html#list">-list function</a>. Descriptions follow.</p>
3625
3626<div class="pre-scrollable highlight">
3627<dl class="row">
3628  <dt class="col-md-4">Polynomial</dt>
3629  <dd class="col-md-8"><p>The <code>Polynomial</code> function takes an arbitrary number of parameters,
3630these being the coefficients of a polynomial, in decreasing order of degree.
3631That is, entering</p>
3632
3633<pre class="highlight"><code>-function Polynomial <var>a</var><sub><var>n</var></sub>,<var>a</var><sub><var>n</var>-1</sub>,...<var>a</var><sub>1</sub>,<var>a</var><sub>0</sub>
3634</code></pre>
3635
3636<p>will invoke a polynomial function given by</p>
3637
3638<pre class="highlight"><code><var>a</var><sub><var>n</var></sub> <b><var>u</var></b><sup><var>n</var></sup> + <var>a</var><sub><var>n</var>-1</sub> <b><var>u</var></b><sup><var>n</var>-1</sup> + ··· <var>a</var><sub>1</sub> <b><var>u</var></b> + <var>a</var><sub>0</sub>,
3639</code></pre>
3640
3641<p>where <b><var>u</var></b> is pixel's original normalized channel value.</p>
3642
3643<p>The <code>Polynomial</code> function can be used in place of <code>Set</code>
3644(the <var>constant</var> polynomial) and <code>Add</code>, <code>Divide</code>,
3645<code>Multiply</code>, and <code>Subtract</code> (some <var>linear</var>
3646polynomials) of the <a href="command-line-options.html#evaluate">-evaluate</a> operator. The <a
3647href="command-line-options.html#level">-level</a> operator also affects channels linearly. Some
3648correspondences follow.</p>
3649
3650<div class="pre-scrollable highlight">
3651<table class="table table-sm table-hover">
3652  <tr>
3653        <td>-evaluate Set <var>value</var> </td>
3654        <td>-function Polynomial <var>value</var></td>
3655        <td>(Constant functions; set <var>value</var>×100% gray when channels are RGB.)</td>
3656  </tr>
3657  <tr>
3658        <td>-evaluate Add <var>value</var> </td>
3659        <td>-function Polynomial 1,<var>value</var></td>
3660  </tr>
3661  <tr>
3662        <td>-evaluate Subtract <var>value</var> </td>
3663        <td>-function Polynomial 1,−<var>value</var></td>
3664  </tr>
3665  <tr>
3666        <td>-evaluate Multiply <var>value</var> </td>
3667        <td>-function Polynomial <var>value</var>,0</td>
3668  </tr>
3669  <tr>
3670        <td>+level  black% x white%</td>
3671        <td>-function Polynomial  A,B</td>
3672        <td>(Reduce contrast. Here, A=(white-black)/100 and  B=black/100.)</td>
3673  </tr>
3674</table>
3675</div>
3676
3677<p>The <code>Polynomial</code> function gives great versatility, since
3678polynomials can be used to fit any continuous curve to any degree of accuracy
3679desired.</p>
3680
3681</dd>
3682<dt class="col-md-4">Sinusoid</dt>
3683<dd class="col-md-8">
3684<p>The <code>Sinusoid</code> function can be used to vary the channel values
3685sinusoidally by setting frequency, phase shift, amplitude, and a bias. These
3686values are given as one to four parameters, as follows,</p>
3687
3688<pre class="highlight"><code>-function <code>Sinusoid</code> <var>freq</var>,[<var>phase</var>,[<var>amp</var>,[<var>bias</var>]]]
3689</code></pre>
3690
3691<p>where <var>phase</var> is in degrees. (The domain [0,1] of the function
3692corresponds to 0 through <var>freq</var>×360 degrees.)
3693The result is that if a pixel's normalized channel value is originally
3694<b><var>u</var></b>, its resulting normalized value is given by </p>
3695
3696<pre class="highlight"><code><var>amp</var> * sin(2*π* (<var>freq</var> * <b><var>u</var></b> + <var>phase</var> / 360)) + <var>bias</var>
3697</code></pre>
3698
3699<p> For example, the following generates a curve that starts and ends at 0.9
3700(when <b><var>u</var></b>=0 and 1, resp.), oscillating three times between
3701.7−.2=.5 and .7+.2=.9. </p>
3702
3703<pre class="highlight"><code>-function Sinusoid 3,-90,.2,.7
3704</code></pre>
3705
3706<p>The default values of <var>amp</var> and <var>bias</var> are both .5. The default for <var>phase</var>
3707is 0.</p>
3708
3709<p>The <code>Sinusoid</code> function generalizes <code>Sin</code> and
3710<code>Cos</code> of the <a href="command-line-options.html#evaluate">-evaluate</a> operator by allowing
3711varying amplitude, phase and bias. The correspondence is as follows.</p>
3712
3713<div class="pre-scrollable highlight">
3714<table class="table table-sm table-hover">
3715  <tr>
3716        <td>-evaluate Sin <var>freq</var> </td>
3717        <td>-function Sinusoid <var>freq</var>,0 </td>
3718  </tr>
3719  <tr>
3720        <td>-evaluate Cos <var>freq</var> </td>
3721        <td>-function Sinusoid <var>freq</var>,90 </td>
3722  </tr>
3723</table>
3724</div>
3725  </dd>
3726<dt class="col-md-4">ArcSin</dt>
3727<dd class="col-md-8">
3728<p>The <code>ArcSin</code> function generates the inverse curve of a Sinusoid,
3729and can be used to generate cylindrical distortion and displacement maps.
3730The curve can be adjusted relative to both the input values and output range
3731of values.</p>
3732
3733<pre class="highlight"><code>-function <code>ArcSin</code> <var>width</var>,[<var>center</var>,[<var>range</var>,[<var>bias</var>]]]
3734</code></pre>
3735
3736<p>with all values given in terms of normalized color values (0.0 for black,
37371.0 for white). Defaulting to values covering the full range from 0.0 to 1.0
3738for bout input (<var>width</var>), and output (<var>width</var>) values. '<code>1.0,0.5,1.0,0.5</code>' </p>
3739
3740<pre class="highlight"><code><var>range</var>/π * asin( 2/<var>width</var> * ( <b><var>u</var></b> - <var>center</var> ) ) + <var>bias</var>
3741</code></pre>
3742
3743</dd>
3744<dt class="col-md-4">ArcTan</dt>
3745<dd class="col-md-8">
3746<p>The <code>ArcTan</code> function generates a curve that smooth crosses from
3747limit values at infinities, though a center using the given slope value.
3748All these values can be adjusted via the arguments.</p>
3749
3750<pre class="highlight"><code>-function <code>ArcTan</code> <var>slope</var>,[<var>center</var>,[<var>range</var>,[<var>bias</var>]]]
3751</code></pre>
3752
3753<p>Defaulting to '<code>1.0,0.5,1.0,0.5</code>'.
3754</p>
3755
3756<pre class="highlight"><code><var>range</var>/π * atan( <var>slope</var>*π * ( <b><var>u</var></b> - <var>center</var> ) ) + <var>bias</var>
3757</code></pre>
3758  </dd>
3759</dl>
3760</div>
3761
3762
3763
3764<div style="margin: auto;">
3765  <h3><a class="anchor" id="fuzz"></a>-fuzz <var>distance</var>{<var>%</var>}</h3>
3766</div>
3767
3768<p class="magick-description">Colors within this <var>distance</var> are considered equal.</p>
3769
3770<p>A number of algorithms search for a target color. By default the color must
3771be exact. Use this option to match colors that are close to the target color
3772in RGB space. For example, if you want to automagically trim the edges of an
3773image with <a href="command-line-options.html#trim">-trim</a> but the image was scanned and the target
3774background color may differ by a small amount. This option can account for
3775these differences.</p>
3776
3777<p>The <var>distance</var> can be in absolute intensity units or, by
3778appending <code>%</code> as a percentage of the maximum possible intensity (255,
377965535, or 4294967295).</p>
3780
3781<p>Use <a href="command-line-options.html#fuzz" >+fuzz</a> to reset the fuzz value to 0.</p>
3782
3783
3784<div style="margin: auto;">
3785  <h3><a class="anchor" id="fx"></a>-fx <var>expression</var></h3>
3786</div>
3787
3788<p class="magick-description">Apply a mathematical expression to an image or image channels.</p>
3789
3790<p>If the first character of <var>expression</var> is <code>@</code>,
3791the expression is read from a file titled by the remaining characters in the
3792string.</p>
3793
3794<p>See <a href="../www/fx.html">FX,
3795The Special Effects Image Operator</a> for a detailed discussion of this
3796option.</p>
3797
3798
3799<div style="margin: auto;">
3800  <h3><a class="anchor" id="gamma"></a>-gamma <var>value</var></h3>
3801</div>
3802
3803<p class="magick-description">Level of gamma correction.</p>
3804
3805<p>The same color image displayed on two different workstations may look
3806different due to differences in the display monitor. Use gamma correction to
3807adjust for this color difference.  Reasonable values extend from
3808<code>0.8</code> to <code>2.3</code>. Gamma less than 1.0 darkens the image and
3809gamma greater than 1.0 lightens it. Large adjustments to image gamma may
3810result in the loss of some image information if the pixel quantum size is only
3811eight bits (quantum range 0 to 255).</p>
3812
3813<p>Gamma adjusts the image's channel values pixel-by-pixel according to
3814a power law, namely, pow(pixel,1/gamma) or pixel^(1/gamma), where pixel is the
3815normalized or 0 to 1 color value. For example, using a value of gamma=2 is the
3816same as taking the square root of the image.</p>
3817
3818<p>Use <a href="command-line-options.html#gamma">+gamma <var>value</var></a> to set the
3819image gamma level without actually adjusting the image pixels. This option
3820is useful if the image is of a known gamma but not set as an image attribute
3821(e.g. PNG images).  Write the "file gamma" which is the reciprocal of the
3822display gamma; e.g., if your image is sRGB and you want to write a PNG gAMA
3823chunk, use</p>
3824
3825<pre class="highlight"><code>magick input.png +gamma .45455 output.png
3826</code></pre>
3827
3828<p>(0.45455 is 1/2.2)</p>
3829
3830<p>Note that gamma adjustments are also available via the <a href="command-line-options.html#level">-level</a> operator.</p>
3831
3832<div style="margin: auto;">
3833  <h3><a class="anchor" id="gaussian-blur"></a>-gaussian-blur <var>radius</var><br />-gaussian-blur <var>radius</var>{x<var>sigma</var>}</h3>
3834</div>
3835
3836<p class="magick-description">Blur the image with a Gaussian operator.</p>
3837
3838<p>Convolve the image with a Gaussian or normal distribution using the given
3839<var >Sigma</var> value.  The formula is:</p>
3840
3841<p class="text-center"><img class="img-thumbnail" alt="gaussian distribution" width="243px" height="42px" src="../images/gaussian-blur.png"/> </p>
3842
3843<p>The <var >Sigma</var> value is the important argument, and
3844determines the actual amount of blurring that will take place. </p>
3845
3846<p>The <var >Radius</var> is only used to determine the size of the
3847array which will hold the calculated Gaussian distribution. It should be an
3848integer.  If not given, or set to zero, IM will calculate the largest possible
3849radius that will provide meaningful results for the Gaussian distribution.
3850</p>
3851
3852<p>The larger the <var >Radius</var> the radius the slower the
3853operation is. However too small a <var >Radius</var>, and severe
3854aliasing effects may result.  As a guideline, <var >Radius</var>
3855should be at least twice the <var >Sigma</var> value, though three
3856times will produce a more accurate result. </p>
3857
3858<p>This differs from the faster <a href="command-line-options.html#blur">-blur</a> operator in that a
3859full 2-dimensional convolution is used to generate the weighted average of the
3860neighboring pixels. </p>
3861
3862<p>The <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting will determine how
3863pixels which are outside the image proper are blurred into the final result.
3864</p>
3865
3866
3867<div style="margin: auto;">
3868  <h3><a class="anchor" id="geometry"></a>-geometry <var>geometry</var></h3>
3869</div>
3870
3871<p class="magick-description">Set the preferred size and location of the image.</p>
3872
3873<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
3874
3875<div style="margin: auto;">
3876  <h3><a class="anchor" id="gravity"></a>-gravity <var>type</var></h3>
3877</div>
3878
3879<p class="magick-description">Sets the current gravity suggestion for various other settings and options.</p>
3880
3881<p>Choices include: <code>NorthWest</code>, <code>North</code>,
3882<code>NorthEast</code>, <code>West</code>, <code>Center</code>, <code>East</code>,
3883<code>SouthWest</code>, <code>South</code>, <code>SouthEast</code>.  Use <a
3884href="command-line-options.html#list">-list gravity</a> to get a complete list of <a
3885href="command-line-options.html#gravity">-gravity</a> settings available in your ImageMagick
3886installation.</p>
3887
3888<p>The direction you choose specifies where to position text or subimages. For
3889example, a gravity of <code>Center</code> forces the text to be centered within
3890the image. By default, the image gravity is <code>undefined</code>. See <a
3891href="command-line-options.html#draw">-draw</a> for more details about graphic primitives.  Only the
3892text primitive of <a href="command-line-options.html#draw">-draw</a> is affected by the <a
3893href="command-line-options.html#gravity">-gravity</a> option.</p>
3894
3895<p>The <a href="command-line-options.html#gravity">-gravity</a> option is also used in concert with the
3896<a href="command-line-options.html#geometry">-geometry</a> setting and other settings or options that
3897take <var>geometry</var> as an argument, such as the <a
3898href="command-line-options.html#crop">-crop</a> option. </p>
3899
3900<p>If a <a href="command-line-options.html#gravity">-gravity</a> setting occurs before another option
3901or setting having a <var>geometry</var> argument that specifies an
3902offset, the offset is usually applied to the point within the image suggested
3903by the <a href="command-line-options.html#gravity">-gravity</a> argument.  Thus, in the following
3904command, for example, suppose the file <code>image.png</code> has dimensions
3905200x100. The offset specified by the argument to <a href="command-line-options.html#region">-region</a>
3906is (−40,+20). The argument to <a href="command-line-options.html#gravity">-gravity</a> is
3907<code>Center</code>, which suggests the midpoint of the image, at the point
3908(100,50). The offset (−40,20) is applied to that point, giving
3909(100−40,50+20)=(60,70), so the specified 10x10 region is located at
3910that point. (In addition, the <a href="command-line-options.html#gravity">-gravity</a> affects the
3911region itself, which is <var>centered</var> at the pixel
3912coordinate (60,70). (See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.)</p>
3913
3914<pre class="highlight"><code>magick image.png -gravity Center -region 10x10-40+20 \
3915  -negate output.png
3916</code></pre>
3917
3918<p>When used as an option to <a href="../www/composite.html">composite</a>, <a
3919href="command-line-options.html#gravity">-gravity</a> gives the direction that the image gravitates
3920within the composite.</p>
3921
3922<p>When used as an option to <a href="montage.html">montage</a>, <a
3923href="command-line-options.html#gravity">-gravity</a> gives the direction that an image gravitates
3924within a tile. The default gravity is <code>Center</code> for this purpose.</p>
3925
3926<p>Use <a href="command-line-options.html#gravity">+gravity</a> to return gravity to its default value.</p>
3927
3928
3929<div style="margin: auto;">
3930  <h3><a class="anchor" id="grayscale"></a>-grayscale <var>method</var></h3>
3931</div>
3932
3933<p class="magick-description">Convert image to grayscale.</p>
3934
3935<p>This will use one of the <a href="command-line-options.html#intensity" >-intensity</a> methods to
3936convert the given image into a grayscale image. </p>
3937
3938<p>For example, to convert an image to (linear) Rec709Luminance grayscale,  type:</p>
3939
3940<pre class="highlight"><code>magick in.png -grayscale Rec709Luminance out.png
3941</code></pre>
3942
3943<p>which is equivalent to:</p>
3944
3945<pre class="highlight">
3946<code>magick in.png -colorspace RGB -colorspace Gray out.png</code>
3947or
3948<code>magick in.png -colorspace LinearGray out.png</code>
3949</pre>
3950
3951<p>Similarly, to convert an image to (non-linear) Rec709Luma grayscale,  type:</p>
3952
3953<pre class="highlight"><code>magick in.png -grayscale Rec709Luma out.png
3954</code></pre>
3955
3956<p>which is equivalent to:</p>
3957
3958<pre class="highlight"><code>magick in.png -colorspace Gray out.png
3959</code></pre>
3960
3961<p>Note that a 'colorspace' intensity method will produce the same result
3962regardless of the current colorpsace of the image. But a 'mathematical'
3963intensity method depends on the current colorspace the image is currently
3964using. </p>
3965
3966<p>While this operation uses an <a href="command-line-options.html#intensity" >-intensity</a> method,
3967it does not use or set the <a href="command-line-options.html#intensity" >-intensity</a> setting, so
3968will not affect other operations that may use that setting.</p>
3969
3970
3971<div style="margin: auto;">
3972  <h3><a class="anchor" id="green-primary"></a>-green-primary <var>x,y</var></h3>
3973</div>
3974
3975<p class="magick-description">Green chromaticity primary point.</p>
3976
3977
3978<div style="margin: auto;">
3979  <h3><a class="anchor" id="hald-clut"></a>-hald-clut</h3>
3980</div>
3981
3982<p class="magick-description">Apply a Hald color lookup table to the image.</p>
3983
3984<p>A Hald color lookup table is a 3-dimensional color cube mapped to 2
3985dimensions.  Create it with the <code>HALD:</code> prefix (e.g. HALD:8).  You
3986can apply any color transformation to the Hald image and then use this option
3987to apply the transform to the image. </p>
3988
3989<pre class="highlight"><code>magick image.png hald.png -hald-clut transform.png
3990</code></pre>
3991
3992<p>This option provides a convenient method for you to use Gimp or Photoshop
3993to make color corrections to the Hald CLUT image and subsequently apply them
3994to multiple images using an ImageMagick script. </p>
3995
3996<p>Note that the representation is only of the normal RGB color space and that
3997the whole color value triplet is used for the interpolated lookup of the
3998represented Hald color cube image.  Because of this the operation is not <a
3999href="command-line-options.html#channel" >-channel</a> setting affected, nor can it adjust or modify an
4000images transparency or alpha/matte channel.</p>
4001
4002<p>See also <a href="command-line-options.html#clut" >-clut</a> which provides color value replacement
4003of the individual color channels, usually involving a simpler grayscale
4004image. E.g:  grayscale to color replacement, or modification by a histogram
4005mapping. </p>
4006
4007
4008<div style="margin: auto;">
4009  <h3><a class="anchor" id="help"></a>-help</h3>
4010</div>
4011
4012<p class="magick-description">Print usage instructions.</p>
4013
4014<div style="margin: auto;">
4015  <h3><a class="anchor" id="highlight-color"></a>-highlight-color <var>color</var></h3>
4016</div>
4017
4018<p class="magick-description">When comparing images, emphasize pixel differences with this color.</p>
4019
4020<div style="margin: auto;">
4021  <h3><a class="anchor" id="hough-lines"></a>-hough-lines <var>width</var>x<var>height</var>{<var>+threshold</var>}</h3>
4022</div>
4023
4024<p class="magick-description">Identify straight lines in the image (e.g. -hough-lines 9x9+195).</p>
4025
4026<p>Use the Hough line detector with any binary edge extracted image to locate and draw any straight lines that it finds.</p>
4027
4028<p>The process accumulates counts for every white pixel in the binary edge image for every possible orientation (for angles from 0 to 179 in 1 deg increments) and distance from the center of the image to the corners (in 1 px increments). It stores the counts in an accumulator matrix of angle vs distance. The size of the accumulator will be 180x(diagonal/2). Next it searches the accumulator for peaks in counts and converts the locations of the peaks to slope and intercept in the normal x,y input image space. The algorithm uses slope/intercepts to find the endpoints clipped to the bounds of the image. The lines are drawn from the given endpoints. The counts are a measure of the length of the lines.</p>.
4029
4030<p>The WxH arguments specify the filter size for locating the peaks in the Hough accumulator. The threshold excludes lines whose counts are less than the threshold value.</p>
4031
4032<p>Use <code><a href="command-line-options.html#background" >-background</a></code> to specify the color of the background onto which the lines will be drawn. The default is black.</p>
4033
4034<p>Use <code><a href="command-line-options.html#fill" >-fill</a></code> to specify the color of the lines. The default is black.</p>
4035
4036<p>Use <code><a href="command-line-options.html#stroke" >-stroke</a></code> and <code><a href="command-line-options.html#strokewidth" >-strokewidth</a></code> to specify the thickness of the lines. The default is black and no strokewidth.</p>
4037
4038<p>A text file listing the endpoints and counts may be created by using the suffix, .mvg, for the output image.</p>
4039
4040<p>Use <code><a href="command-line-options.html#define" >-define</a> hough-lines:accumulator=true</code> to return the accumulator image in addition to the lines image.</p>
4041
4042<div style="margin: auto;">
4043  <h3><a class="anchor" id="iconGeometry"></a>-iconGeometry <var>geometry</var></h3>
4044</div>
4045
4046<p class="magick-description">Specify the icon geometry.</p>
4047
4048<p>Offsets, if present in the geometry specification, are handled in the same
4049manner as the <a href="command-line-options.html#geometry">-geometry</a> option, using X11 style to
4050handle negative offsets.</p>
4051
4052<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
4053
4054<div style="margin: auto;">
4055  <h3><a class="anchor" id="iconic"></a>-iconic</h3>
4056</div>
4057
4058<p class="magick-description">Start in icon mode in X Windows", 'animate', 'display</p>
4059
4060<div style="margin: auto;">
4061  <h3><a class="anchor" id="identify"></a>-identify</h3>
4062</div>
4063
4064<p class="magick-description">Identify the format and characteristics of the image.</p>
4065
4066<p>This information is printed: image scene number; image name; image size;
4067the image class (<var>DirectClass</var> or <var>PseudoClass</var>); the total number of unique colors; and the
4068number of seconds to read and transform the image. Refer to <a href="miff.html">MIFF</a> for
4069a description of the image class.</p>
4070
4071<p>If <a href="command-line-options.html#colors">-colors</a> is also specified, the total unique colors
4072in the image and color reduction error values are printed. Refer to <a
4073href="../www/quantize.html">color
4074reduction algorithm</a> for a description of these values.</p>
4075
4076<p>If <a href="command-line-options.html#verbose">-verbose</a> precedes this option, copious
4077amounts of image properties are displayed including image statistics, profiles,
4078image histogram, and others.</p>
4079
4080<div style="margin: auto;">
4081  <h3><a class="anchor" id="ift"></a>-ift</h3>
4082</div>
4083
4084<p class="magick-description">Implements the inverse discrete Fourier transform (DFT).</p>
4085
4086<p>This option is new as of ImageMagick 6.5.4-3 (and now working for Windows
4087users in ImageMagick 6.6.0-9). It transforms a pair of magnitude and phase
4088images from the frequency domain to a single image in the normal or spatial
4089domain. See for example, <a
4090href="http://en.wikipedia.org/wiki/Fourier_transform">Fourier Transform</a>,
4091<a href="http://en.wikipedia.org/wiki/DFT">Discrete Fourier Transform</a> and
4092<a href="http://en.wikipedia.org/wiki/FFT">Fast Fourier Transform</a>.</p>
4093
4094<p>For example, depending upon the image format used to store the result of
4095the <a href="command-line-options.html#fft">-fft</a>, one would use either</p>
4096
4097<pre class="highlight"><code>magick fft_image.miff -ift fft_image_ift.png
4098</code></pre>
4099
4100<p>or</p>
4101
4102<pre class="highlight"><code>magick fft_image-0.png fft_image-1.png -ift fft_image_ift.png
4103</code></pre>
4104
4105<p>The resulting image may need to be cropped due to padding introduced when
4106the original image, prior to the <a href="command-line-options.html#fft">-fft</a> or <a
4107href="command-line-options.html#fft">+fft</a>, was not square or even dimensioned. Any padding is at
4108the right and/or bottom sides of the image.</p>
4109
4110<p>The <a href="http://www.fftw.org/">FFTW</a> delegate library is required to
4111use <a href="command-line-options.html#ift">-ift</a>.</p>
4112
4113<p>Use <a href="command-line-options.html#ift">+ift</a> (with HDRI enabled) to transform a pair of real
4114and imaginary images from the frequency domain to a single image in the normal
4115(spatial) domain.</p>
4116
4117<p>By default the IFT is not normalized (and the FFT is). Use "<code><a href="command-line-options.html#define" >-define</a> fourier:normalize=inverse</code> to explicitly normalize the IFT and unnormalize the FFT.</p>
4118
4119<div style="margin: auto;">
4120  <h3><a class="anchor" id="immutable"></a>-immutable</h3>
4121</div>
4122
4123<p class="magick-description">Make image immutable.</p>
4124
4125<div style="margin: auto;">
4126  <h3><a class="anchor" id="implode"></a>-implode <var>factor</var></h3>
4127</div>
4128
4129<p class="magick-description">Implode image pixels about the center.</p>
4130
4131<div style="margin: auto;">
4132  <h3><a class="anchor" id="insert"></a>-insert <var>index</var></h3>
4133</div>
4134
4135<p class="magick-description">Insert the last image into the image sequence.</p>
4136
4137<p>This option takes last image in the current image sequence and inserts it
4138at the given index. If a negative index is used, the insert position is
4139calculated before the last image is removed from the sequence. As such
4140<code>-insert -1</code> will result in no change to the image sequence.</p>
4141
4142<p>The <code>+insert</code> option is equivalent to <code>-insert -1</code>. In
4143other words, insert the last image, at the end of the current image sequence.
4144Consequently this has no effect on the image sequence order.</p>
4145
4146<div style="margin: auto;">
4147  <h3><a class="anchor" id="intensity"></a>-intensity <var>method</var></h3>
4148</div>
4149
4150<p class="magick-description">Method to generate intensity value from pixel.</p>
4151
4152<p>ImageMagick provides a number of methods used in situations where an
4153operator needs to determine a single grayscale value for some purpose, from
4154an image with red, green, and blue pixel components. Typically the
4155<code>Rec709Luma</code> formula is used, which is the same formula used when converting images to <code>-colorspace gray</code>. </p>
4156
4157<p>The following formulas are currently provided, and will first convert
4158the pixel values to linear-RGB or non-linear sRGB colorspace before
4159being applied to calculate the final greyscale value. </p>
4160
4161<div class="pre-scrollable highlight">
4162<dl class="row">
4163<dt class="col-md-4">Rec601Luma</dt><dd class="col-md-8">      0.298839R' + 0.586811G'+ 0.114350B'</dd>
4164<dt class="col-md-4">Rec601Luminance</dt><dd class="col-md-8"> 0.298839R + 0.586811G + 0.114350B</dd>
4165<dt class="col-md-4">Rec709Luma</dt><dd class="col-md-8">      0.212656R' + 0.715158G' + 0.072186B'</dd>
4166<dt class="col-md-4">Rec709Luminance</dt><dd class="col-md-8"> 0.212656R + 0.715158G + 0.072186B</dd>
4167<dt class="col-md-4">Brightness</dt><dd class="col-md-8">      max(R', G', B')</dd>
4168<dt class="col-md-4">Lightness</dt><dd class="col-md-8">       (min(R', G', B') + max(R', G', B')) / 2.0</dd>
4169</dl>
4170</div>
4171
4172<p>Note that the above R,G,B values is the image's linear-RGB values, while
4173R',G',B' are sRGB non-linear values. </p>
4174
4175<p>These intensity methods are mathematical in nature and will use the
4176current value in the images respective R,G,B channel regardless of
4177what that is, or what colorspace the image is currently using.</p>
4178
4179<div class="pre-scrollable highlight">
4180<dl class="row">
4181<dt class="col-md-4">Average</dt><dd class="col-md-8">(R' + G' + B') / 3.0</dd>
4182<dt class="col-md-4">MS</dt><dd class="col-md-8">(R'^2 + G'^2 + B'^2) / 3.0</dd>
4183<dt class="col-md-4">RMS</dt><dd class="col-md-8">sqrt( (R'^2 + G'^2 + B'^2) / 3.0 )</dd>
4184</dl>
4185</div>
4186
4187<p>These methods are often used for other purposes, such as generating a
4188grayscale difference image between two color images (using <a href="command-line-options.html#compose"
4189>-compose</a> '<code>Difference</code>' composition. </p>
4190
4191<p> For example The 'MS' (Mean Squared) setting is good for minimizing color
4192error comparisions.  While...  The method 'RMS' (Root Mean Squared) for
4193example is appropriate for calculating color vector distance, from a color
4194difference image.  This is equivalent to the color only component of the <a
4195href="command-line-options.html#fuzz" >-fuzz</a> factor color compare setting.  </p>
4196
4197<p>See also <a href="command-line-options.html#grayscale" >-grayscale</a> which applies one of the above
4198grayscaling formula directly to an image without setting the <a
4199href="command-line-options.html#intensity" >-intensity</a> setting.</p>
4200
4201<p>The <a href="command-line-options.html#colorspace" >-colorspace gray</a> image conversion also uses
4202the current intensity setting, but will always convert the image to the
4203appropriate sRGB or linear-RGB colorspace before appling the above
4204function.</p>
4205
4206<p>To print a complete list of possible pixel intensity setting methods, use <a href="command-line-options.html#list">-list intensity</a>.</p>
4207
4208<p>Operators affected by the <a href="command-line-options.html#intensity" >-intensity</a> setting include:</p>
4209
4210<pre class="highlight"><code>-adaptive-blur
4211-adaptive-sharpen
4212-black-threshold
4213-clut (when mapping greyscale CLUT image to alpha channel if set by -channels)
4214-colors for gray colorspace
4215-compose {LightenIntensity, DarkenIntensity, CopyOpacity, CopyBlack}
4216-contrast-stretch
4217-distort {ErodeIntensity, DilateIntensity}
4218-normalize
4219-random-threshold
4220-range-threshold
4221-selective-blur
4222-shade
4223-threshold
4224-tint
4225-white-threshold
4226</code></pre>
4227
4228<div style="margin: auto;">
4229  <h3><a class="anchor" id="intent"></a>-intent <var>type</var></h3>
4230</div>
4231
4232<p class="magick-description">Use this type of rendering intent when managing the image color.</p>
4233
4234<p>Use this option to affect the color management operation of an image (see
4235<a href="command-line-options.html#profile">-profile</a>).  Choose from these intents: <code>Absolute,
4236Perceptual, Relative, Saturation</code>.</p>
4237
4238<p>The default intent is Perceptual for the sRGB colorspace and undefined for the RGB and gray colorspaces.</p>
4239
4240<p>To print a complete list of rendering intents, use <a href="command-line-options.html#list">-list intent</a>.</p>
4241
4242<div style="margin: auto;">
4243  <h3><a class="anchor" id="interlace"></a>-interlace <var>type</var></h3>
4244</div>
4245
4246<p class="magick-description">The type of interlacing scheme.</p>
4247
4248<p>Choose from:</p>
4249
4250<pre class="highlight"><code>none
4251line
4252plane
4253partition
4254JPEG
4255GIF
4256PNG
4257</code></pre>
4258
4259<p>This option is used to specify the type of interlacing scheme for raw image
4260formats such as <code>RGB</code> or <code>YUV</code>.</p>
4261
4262<p><code>None</code> means do not interlace (RGBRGBRGBRGBRGBRGB...),</p>
4263
4264<p><code>Line</code> uses scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...), and.</p>
4265
4266<p><code>Plane</code> uses plane interlacing (RRRRRR...GGGGGG...BBBBBB...).</p>
4267
4268<p><code>Partition</code> is like plane except the different planes are saved to
4269individual files (e.g. image.R, image.G, and image.B).</p>
4270
4271<p>Use <code>Line</code> or <code>Plane</code> to create an <code>interlaced
4272PNG</code> or <code>GIF</code> or <code>progressive JPEG</code> image.</p>
4273
4274<p>To print a complete list of interlacing schemes, use <a href="command-line-options.html#list">-list
4275interlace</a>.</p>
4276
4277<div style="margin: auto;">
4278  <h3><a class="anchor" id="interpolate"></a>-interpolate <var>type</var></h3>
4279</div>
4280
4281<p class="magick-description">Set the pixel color interpolation method to use when looking up a color based on a floating point or real value.</p>
4282
4283<p>When looking up the color of a pixel using a non-integer floating point
4284value, you typically fall in between the pixel colors defined by the source
4285image. This setting determines how the color is determined from the colors of
4286the pixels surrounding that point.  That is how to determine the color of a
4287point that falls between two, or even four different colored pixels. </p>
4288
4289<div class="pre-scrollable highlight">
4290<dl class="row">
4291  <dt class="col-md-4">average</dt>
4292  <dd class="col-md-8">The average color of the surrounding four pixels</dd>
4293  <dt class="col-md-4">average4</dt>
4294  <dd class="col-md-8">The average color of the surrounding four pixels</dd>
4295  <dt class="col-md-4">average9</dt>
4296  <dd class="col-md-8">The average color of the surrounding nine pixels</dd>
4297  <dt class="col-md-4">average16</dt>
4298  <dd class="col-md-8">The average color of the surrounding sixteen pixels</dd>
4299  <dt class="col-md-4">background</dt>
4300  <dd class="col-md-8"> </dd>
4301  <dt class="col-md-4">bilinear</dt>
4302  <dd class="col-md-8">A double linear interpolation of pixels (the default)</dd>
4303  <dt class="col-md-4">blend</dt>
4304  <dd class="col-md-8"> </dd>
4305  <dt class="col-md-4">catrom</dt>
4306  <dd class="col-md-8">Fitted bicubic-spines of surrounding 16 pixels</dd>
4307  <dt class="col-md-4">integer</dt>
4308  <dd class="col-md-8">The color of the top-left pixel (floor function)</dd>
4309  <dt class="col-md-4">mesh</dt>
4310  <dd class="col-md-8">Divide area into two flat triangular interpolations</dd>
4311  <dt class="col-md-4">nearest-neighbor</dt>
4312  <dd class="col-md-8">The nearest pixel to the lookup point (rounded function)</dd>
4313  <dt class="col-md-4">spline</dt>
4314  <dd class="col-md-8">Direct spline curves (colors are blurred)</dd>
4315</dl>
4316</div>
4317
4318<p>This most important for distortion operators such as <a href="command-line-options.html#distort"
4319>-distort</a>, <a href="command-line-options.html#implode" >-implode</a>, <a href="command-line-options.html#transform"
4320>-transform</a> and <a href="command-line-options.html#fx" >-fx</a>. </p>
4321
4322<p>To print a complete list of interpolation methods, use <a href="command-line-options.html#list">-list interpolate</a>.</p>
4323
4324<p>See also <a href="command-line-options.html#virtual-pixel" >-virtual-pixel</a>, for control of the
4325lookup for positions outside the boundaries of the image. </p>
4326
4327
4328<div style="margin: auto;">
4329  <h3><a class="anchor" id="interline-spacing"></a>-interline-spacing <var>value</var></h3>
4330</div>
4331
4332<p class="magick-description">The space between two text lines.</p>
4333
4334<div style="margin: auto;">
4335  <h3><a class="anchor" id="interword-spacing"></a>-interword-spacing <var>value</var></h3>
4336</div>
4337
4338<p class="magick-description">The space between two words.</p>
4339
4340<div style="margin: auto;">
4341  <h3><a class="anchor" id="kerning"></a>-kerning <var>value</var></h3>
4342</div>
4343
4344<p class="magick-description">The space between two letters.</p>
4345
4346<div style="margin: auto;">
4347  <h3><a class="anchor" id="kmeans"></a>-kmeans <var>colors</var>{x<var>iterations</var>}{+<var>tolerance</var>}</h3>
4348</div>
4349
4350<p class="magick-description">Kmeans (iterative) color reduction (e.g. <code>-kmeans 5x100+0.01</code>). Colors is the desired number of colors. Initial colors are found using color quantization. Iterations is the stopping number of iterations (default=100). Convergence is the stopping threshold on the color change between iterations (default=0.01). Processing finishes, if either iterations or tolerance are reached. Use <code>-define kmeans:seed-colors=<var>color-list</var></code> to initialize the colors, where color-list is a semicolon delimited list of seed colors (e.g. <code>-define kmeans:seed-colors="red;sRGB(19,167,254);#00ffff</code>). A color list overrides the color quantization. A non-empty list of colors overrides the number of colors. Any unassigned initial colors are assigned  random colors from the image.</p>
4351
4352<div style="margin: auto;">
4353  <h3><a class="anchor" id="kuwahara"></a>-kuwahara <var>radius</var><br />-kuwahara <var>radius</var>{x<var>sigma</var>}</h3>
4354</div>
4355
4356<p class="magick-description">Edge preserving noise reduction filter.</p>
4357
4358<p>The <var >radius</var> is more important than the <var >sigma</var>. If <var >sigma</var> is left off, it will be computed automatically from the <var >radius</var> as <var >sigma</var>=<var >radius</var>-0.5. The <var >sigma</var> provides a bit of additional smoothing control.</p>
4359
4360
4361<div style="margin: auto;">
4362  <h3><a class="anchor" id="label"></a>-label <var>name</var></h3>
4363</div>
4364
4365<p class="magick-description">Assign a label to an image.</p>
4366
4367<p>Use this option to assign a specific label to the image, as it is read in
4368or created.  You can use the <a href="command-line-options.html#set" >-set</a> operation to re-assign
4369a the labels of images already read in.  Image formats such as TIFF, PNG,
4370MIFF, supports saving the label information with the image.</p>
4371
4372<p>When saving an image to a <var>PostScript</var> file, any label
4373assigned to an image is used as a header string to print above the postscript
4374image. </p>
4375
4376<p>You can include the image filename, type, width, height, or other image
4377attribute by embedding special format character.  See <a href="../www/escape.html">Format and Print Image
4378Properties</a> for details of the percent escape codes.</p>
4379
4380<p>For example,</p>
4381
4382<pre class="highlight"><code>-label "%m:%f %wx%h"  bird.miff
4383</code></pre>
4384
4385<p>assigns an image label of <code>MIFF:bird.miff 512x480</code> to the
4386"<code>bird.miff</code>" image and whose width is 512 and height is 480, as it
4387is read in.  If a  <a href="command-line-options.html#label">+label</a> option was used instead, any
4388existing label present in the image would be used.  You can remove all labels
4389from an image by assigning the empty string. </p>
4390
4391<p>A label is not drawn on the image, but is embedded in the image datastream
4392via <var>Label</var> tag or similar mechanism. If you want the label to be
4393visible on the image itself, use the <a href="command-line-options.html#draw">-draw</a> option, or
4394during the final processing in the creation of an image montage.</p>
4395
4396<p>If the first character of <var>string</var> is <var>@</var>, the image label is read from a file titled by the
4397remaining characters in the string. Labels in a file are literal, no embedded
4398formatting characters are recognized.</p>
4399
4400
4401<div style="margin: auto;">
4402  <h3><a class="anchor" id="lat"></a>-lat <var>width</var><br />-lat <var>width</var>x<var>height</var>{<var>+-</var>}<var>offset</var>{<var>%</var>}</h3>
4403</div>
4404
4405<p class="magick-description">Perform local adaptive threshold.</p>
4406
4407<p>Adaptively threshold each pixel based on the value of pixels in a
4408surrounding window.  If the current pixel is lighter than this average plus
4409the optional <code>offset</code>, then it is made white, otherwise it is made
4410black.  Small variations in pixel values such as found in scanned documents
4411can be ignored if offset is positive. A negative offset will make it more
4412sensitive to those small variations. </p>
4413
4414<p>This is commonly used to threshold images with an uneven background.  It is
4415based on the assumption that average color of the small window is the
4416the local background color, from which to separate the foreground color. </p>
4417
4418
4419<div style="margin: auto;">
4420  <h3><a class="anchor" id="layers"></a>-layers <var>method</var></h3>
4421</div>
4422
4423<p class="magick-description">Handle multiple images forming a set of image layers or animation frames.</p>
4424
4425<p>Perform various image operation methods to a ordered sequence of images
4426which may represent either a set of overlaid 'image layers', a GIF disposal
4427animation, or a fully-'coalesced' animation sequence. </p>
4428
4429<div class="pre-scrollable highlight">
4430<table class="table table-sm table-hover">
4431  <tbody>
4432  <tr>
4433    <th style="width: 8%">Method</th>
4434    <th>Description</th>
4435  </tr>
4436
4437  <tr>
4438    <td>compare-any</td>
4439    <td>Crop the second and later frames to the smallest rectangle
4440        that contains all the differences between the two images.  No GIF <a
4441        href="command-line-options.html#dispose" >-dispose</a> methods are taken into account. </td>
4442  </tr>
4443
4444  <tr><td></td><td>This exactly the same as the <a href="command-line-options.html#deconstruct"
4445        >-deconstruct</a> operator, and does not preserve animations normal
4446        working, especially when animation used layer disposal methods such as
4447        '<code>Previous</code>' or '<code>Background</code>'. </td>
4448  </tr>
4449
4450  <tr>
4451    <td>compare-clear</td>
4452    <td>As '<code>compare-any</code>' but crop to the bounds of any
4453       opaque pixels which become transparent in the second frame. That is the
4454       smallest image needed to mask or erase pixels for the next frame. </td>
4455  </tr>
4456
4457  <tr>
4458    <td>compare-overlay</td>
4459    <td>As '<code>compare-any</code>' but crop to pixels that add
4460       extra color to the next image, as a result of overlaying color pixels.
4461       That is the smallest single overlaid image to add or change colors. </td>
4462   </tr>
4463
4464   <tr><td></td><td>This can be used with the <a href="command-line-options.html#compose" >-compose</a> alpha
4465       composition method '<code>change-mask</code>', to reduce the image to
4466       just the pixels that need to be overlaid. </td>
4467   </tr>
4468
4469  <tr>
4470    <td>coalesce</td>
4471    <td>Equivalent to a call to the <a href="command-line-options.html#coalesce"
4472        >-coalesce</a> operator.  Apply the layer disposal methods set in the
4473        current image sequence to form a fully defined animation sequence, as
4474        it should be displayed.  Effectively converting a GIF animation into a
4475        'film strip'-like animation.  </td>
4476  </tr>
4477
4478  <tr>
4479    <td>composite</td>
4480    <td>Alpha Composition of two image lists, separated by a
4481        "<code>null:</code>" image, with the destination image list first, and
4482        the source images last.  An image from each list are composited
4483        together until one list is finished. The separator image and source
4484        image lists are removed. </td>
4485  </tr>
4486
4487
4488  <tr><td></td>
4489    <td>The <a href="command-line-options.html#geometry" >-geometry</a> offset is adjusted according
4490        to <a href="command-line-options.html#gravity" >-gravity</a> in accordance of the virtual
4491        canvas size of the first image in each list. Unlike a normal <a
4492        href="command-line-options.html#composite" >-composite</a> operation, the canvas offset is also
4493        added to the final composite positioning of each image. </td> </tr>
4494
4495  <tr><td></td>
4496    <td>If one of the image lists only contains one image, that image is
4497        applied to all the images in the other image list, regardless of which
4498        list it is. In this case it is the image meta-data of the list which
4499        preserved.  </td>
4500  </tr>
4501
4502
4503  <tr>
4504    <td>dispose</td>
4505    <td>This like '<code>coalesce</code>' but shows the look of
4506        the animation after the layer disposal method has been applied, before
4507        the next sub-frame image is overlaid. That is the 'dispose' image that
4508        results from the application of the GIF <a href="command-line-options.html#dispose"
4509        >-dispose</a> method.  This allows you to check what
4510        is going wrong with a particular animation you may be developing.
4511        </td>
4512  </tr>
4513
4514  <tr>
4515    <td>flatten</td>
4516    <td>Create a canvas the size of the first images virtual
4517        canvas using the current <a href="command-line-options.html#background" >-background</a> color,
4518        and <a href="command-line-options.html#compose" >-compose</a> each image in turn onto that
4519        canvas.  Images falling outside that canvas is clipped. Final
4520        image will have a zero virtual canvas offset. </td>
4521  </tr>
4522
4523  <tr><td></td>
4524    <td>This usually used as one of the final 'image layering' operations
4525        overlaying all the prepared image layers into a final image. </td>
4526  </tr>
4527
4528  <tr><td></td>
4529    <td>For a single image this method can also be used to fillout a virtual
4530        canvas with real pixels, or to underlay an opaque color to remove
4531        transparency from an image.</td>
4532  </tr>
4533
4534
4535  <tr>
4536    <td>merge</td>
4537    <td>As 'flatten' method but merging all the given image
4538        layers to create a new layer image just large enough to hold all the
4539        image without clipping or extra space. The new images virtual offset
4540        will preserve the position of the new layer, even if this offset is
4541        negative.  The virtual canvas size of the first image is preserved.
4542        </td>
4543  </tr>
4544
4545  <tr><td></td><td>Caution is advised when handling image layers with
4546        negative offsets as few image file formats handle them correctly.
4547        Following this operation method with <a href="command-line-options.html#repage" >+repage</a>
4548        will remove the layer offset, and create an image in which all the
4549        overlaid image positions relative to each other is preserved, though
4550        not necessarily exactly where you specified them.
4551        </td>
4552  </tr>
4553
4554  <tr><td></td><td>See also 'trim-bounds' below which is closely related but
4555        without  doing the'flatten' to merge the images together. </td>
4556  </tr>
4557
4558  <tr>
4559    <td>mosaic</td>
4560    <td>As 'flatten' method but expanding the initial canvas size
4561        of the first image in a positive direction only so as to hold all the
4562        image layers.  However as a virtual canvas is 'locked' to the origin,
4563        by its own definition, image layers with a negative offsets will still
4564        become clipped by the top and left edges. See 'merge' or 'trim-bounds'
4565        if this could be a problem. </td>
4566
4567  </tr>
4568
4569  <tr><td></td><td>This method is commonly used to layout individual image
4570        using various offset but without knowing the final canvas size. The
4571        resulting image will, like 'flatten' not have any virtual offset, so
4572        can be saved to any image file format. </td>
4573  </tr>
4574
4575
4576  <tr>
4577    <td>optimize</td>
4578    <td>Optimize a coalesced animation, into GIF animation using
4579        a number of general techniques.  This currently a short cut to
4580        apply both the '<code>optimize-frame</code>', and
4581        '<code>optimize-transparency</code>' methods but may be expanded to
4582        include other optimization methods as they are developed. </td>
4583  </tr>
4584
4585  <tr>
4586    <td>optimize-frame</td>
4587    <td>Optimize a coalesced animation, into GIF animation by
4588        reducing the number of pixels per frame as much as possible by
4589        attempting to pick the best layer disposal method to use, while ensuring
4590        the result will continue to animate properly. </td>
4591  </tr>
4592
4593  <tr><td></td><td> There is no guarantee that the best optimization is found.
4594        But then no reasonably fast GIF optimization algorithm can do this.
4595        However this does seem to do better than most other GIF frame
4596        optimizers seen. </td>
4597  </tr>
4598
4599  <tr>
4600    <td>optimize-plus</td>
4601    <td>As '<code>optimize-frame</code>' but attempt to improve the
4602        overall optimization by adding extra frames to the animation, without
4603        changing the final look or timing of the animation.  The frames are
4604        added to attempt to separate the clearing of pixels from the
4605        overlaying of new additional pixels from one animation frame to the
4606        next.  If this does not improve the optimization (for the next frame
4607        only), it will fall back to the results of the previous normal
4608        '<code>optimize-frame</code>' technique. </td>
4609  </tr>
4610
4611  <tr><td></td><td>There is the possibility that the change in the disposal
4612        style will result in a worsening in the optimization of later frames,
4613        though this is unlikely. In other words there no guarantee that it is
4614        better than the normal '<code>optimize-frame</code>' technique. For some
4615        animations however you can get a vast improvement in the final
4616        animation size. </td>
4617  </tr>
4618
4619  <tr>
4620    <td>optimize-transparency</td>
4621    <td>Given a GIF animation, replace any pixel in the sub-frame
4622        overlay images with transparency, if it does not change the resulting
4623        animation by more than the current <a href="command-line-options.html#fuzz" >-fuzz</a> factor.
4624        </td>
4625  </tr>
4626
4627  <tr><td></td><td>This should allow a existing frame optimized GIF animation
4628        to compress into a smaller file size due to larger areas of one
4629        (transparent) color rather than a pattern of multiple colors repeating
4630        the current disposed image of the last frame. </td>
4631  </tr>
4632
4633  <tr>
4634    <td>remove-dups</td>
4635    <td>Remove (and merge time delays) of duplicate consecutive
4636        images, so as to simplify layer overlays of coalesced animations.
4637        </td>
4638  </tr>
4639
4640   <tr><td></td><td>Usually this a result of using a constant time delay
4641        across the whole animation, or after a larger animation was split into
4642        smaller sub-animations.  The duplicate frames could also have been
4643        used as part of some frame optimization methods. </td>
4644  </tr>
4645
4646  <tr>
4647    <td>remove-zero</td>
4648    <td>Remove any image with a zero time delay, unless ALL the
4649        images have a zero time delay (and is not a proper timed animation, a
4650        warning is then issued). </td>
4651  </tr>
4652
4653  <tr><td></td><td>In a GIF animation, such images are usually frames which
4654        provide partial intermediary updates between the frames that are
4655        actually displayed to users.  These frames are usually added for
4656        improved frame optimization in GIF animations. </td>
4657  </tr>
4658
4659  <tr>
4660    <td>trim-bounds</td>
4661    <td>Find the bounds of all the images in the current
4662        image sequence, then adjust the offsets so all images are contained on
4663        a minimal positive canvas. None of the image data is modified or
4664        merged, only the individual image virtual canvas size and offset.
4665        All the images is given the same canvas size, and will have
4666        a positive offset, but will remain in the same position relative to
4667        each other. As a result of the minimal canvas size at least one image
4668        will touch every edge of that canvas.  The image data touching those
4669        edges however may be transparent.  </td>
4670  </tr>
4671
4672  <tr><td></td><td>The result is much like if you used 'merge' followed by a
4673        <a href="command-line-options.html#repage" >+repage</a> option, except that all the images
4674        have been kept separate.  If 'flatten' is used after using
4675        'trim-bounds' you will get the same result.  </td>
4676  </tr>
4677
4678  </tbody>
4679</table>
4680</div>
4681
4682<p>To print a complete list of layer types, use <a href="command-line-options.html#list">-list layers</a>.</p>
4683
4684<p>The operators <a href="command-line-options.html#coalesce" >-coalesce</a>, <a href="command-line-options.html#deconstruct"
4685>-deconstruct</a>, <a href="command-line-options.html#flatten" >-flatten</a>, and <a href="command-line-options.html#mosaic"
4686>-mosaic</a> are only aliases for the above methods and may be depreciated in
4687the future.  Also see  <a href="command-line-options.html#page" >-page</a>,  <a href="command-line-options.html#repage"
4688>-repage</a> operators, the <a href="command-line-options.html#compose" >-compose</a> setting, and the
4689GIF <a href="command-line-options.html#dispose" >-dispose</a> and  <a href="command-line-options.html#delay" >-delay</a>
4690settings. </p>
4691
4692
4693<div style="margin: auto;">
4694  <h3><a class="anchor" id="level"></a>-level <var>black_point</var>{,<var>white_point</var>}{<var>%</var>}{,<var>gamma</var>}</h3>
4695</div>
4696
4697<p class="magick-description">Adjust the level of image channels.</p>
4698
4699<p>Given one, two or three values delimited with commas: black-point,
4700white-point, gamma (for example: 10,250,1.0 or 2%,98%,0.5). The black and
4701white points range from 0 to <var>QuantumRange</var>, or from 0 to
4702100%; if the white point is omitted it is set to (<var>QuantumRange</var> - black_point), so as to center contrast changes.
4703If a <code>%</code> sign is present anywhere in the string, both black and white
4704points are percentages of the full color range.  Gamma will do a <a
4705href="command-line-options.html#gamma">-gamma</a> adjustment of the values.  If it is omitted, the
4706default of 1.0 (no gamma correction) is assumed.</p>
4707
4708<p>In normal usage (<code>-level</code>) the image values are stretched so that
4709the given '<code>black_point</code>' value in the original image is set to zero
4710(or black), while the given '<code>white_point</code>' value is set to <var>QuantumRange</var> (or white).  This provides you with direct
4711contrast adjustments to the image.  The '<code>gamma</code>' of the resulting
4712image will then be adjusted. </p>
4713
4714<p>From ImageMagick v6.4.1-9 using the plus form of the operator
4715(<code>+level</code>) or adding the special '!' flag anywhere in the argument
4716list, will cause the operator to do the reverse of the level adjustment.  That
4717is a zero, or <var>QuantumRange</var> value (black, and white, resp.)
4718in the original image, is adjusted to the given level values, allowing you to
4719de-contrast, or compress the channel values within the image. The
4720'<code>gamma</code>' is adjusted before the level adjustment to de-contrast the
4721image is made. </p>
4722
4723<p>Only the channels defined by the current <a href="command-line-options.html#channel">-channel</a>
4724setting are adjusted (defaults to RGB color channels only), allowing you to
4725limit the effect of this operator. </p>
4726
4727<p>Please note that the transparency channel is treated as 'matte'
4728values (0 is opaque) and not as 'alpha' values (0 is transparent).</p>
4729
4730
4731<div style="margin: auto;">
4732  <h3><a class="anchor" id="level-colors"></a>-level-colors {<var>black_color</var>}{,}{<var>white_color</var>}</h3>
4733</div>
4734
4735<p class="magick-description">Adjust the level of an image using the provided dash separated colors.</p>
4736
4737<p>This function is exactly like <a href="command-line-options.html#level">-level</a>, except that the
4738value for each color channel is determined by the
4739'<code>black_color</code>' and '<code>white_color</code>' colors given (as
4740described under the <a href="command-line-options.html#fill">-fill</a> option). </p>
4741
4742<p>This effectively means the colors provided to <code>-level-colors</code>
4743is mapped to become 'black' and 'white' respectively, with all the other
4744colors linearly adjusted (or clipped) to match that change. Each channel is
4745adjusted separately using the channel values of the colors specified. </p>
4746
4747<p>On the other hand the plus form of the operator (<code>+level-colors</code>)
4748will map the image color 'black' and 'white' to the given colors
4749respectively, resulting in a gradient (de-contrasting) tint of the image to
4750those colors. This can also be used to convert a plain grayscale image into a
4751one using the gradient of colors specified. </p>
4752
4753<p>By supplying a single color with a comma separator either before or after
4754that color, will just replace the respective 'black' or 'white' point
4755respectively.  But if no comma separator is provided, the given color is
4756used for both the black and white color points, making the operator either
4757threshold the images around that color (- form) or set all colors to that
4758color (+ form). </p>
4759
4760
4761<div style="margin: auto;">
4762  <h3><a class="anchor" id="limit"></a>-limit <var>type value</var></h3>
4763</div>
4764
4765<p class="magick-description">Set the pixel cache resource limit.</p>
4766
4767<p>Choose from: <code>width</code>, <code>height</code>, <code>area</code>, <code>memory</code>, <code>map</code>, <code>disk</code>, <code>file</code>, <code>thread</code>,  <code>throttle</code>, or <code>time</code>.</p>
4768
4769<p>The value for <code>file</code> is in number of files. The other limits are
4770in bytes. Define arguments for the memory, map, area, and disk resource limits
4771with SI prefixes (.e.g 100MB).</p>
4772
4773<p>By default the limits are 768 files, 3GB of image area, 1.5GiB memory, 3GiB
4774memory map, and 18.45EB of disk.  These limits are adjusted relative to the
4775available resources on your computer if this information is available.   When
4776any limit is reached, ImageMagick fails in some fashion but attempts to take
4777compensating actions, if possible. For example, the following limits
4778memory:</p>
4779
4780<pre class="highlight"><code>-limit memory 32MiB -limit map 64MiB
4781</code></pre>
4782
4783<p>Use <a href="command-line-options.html#list">-list resource</a> to list the current limits. For example, our system shows these limits:</p>
4784
4785<pre class="highlight"><code>-> identify -list resource
4786Resource limits:
4787  Width: 100MP
4788  Height: 100MP
4789  Area: 25.181GB
4790  Memory: 11.726GiB
4791  Map: 23.452GiB
4792  Disk: unlimited
4793  File: 768
4794  Thread: 12
4795  Throttle: 0
4796  Time: unlimited
4797</code></pre>
4798
4799<p>Requests for pixel storage to keep intermediate images are satisfied by one
4800of three resource categories: in-memory pool, memory-mapped files pool, and
4801disk pool (in that order) depending on the <a class="text-nowrap" href="command-line-options.html#limit">-limit</a> settings
4802and whether the system honors a resource request. If the total size of
4803allocated pixel storage in the given pool reaches the corresponding limit, the
4804request is passed to the next pool. Additionally, requests that exceed the
4805<code>area</code> limit automagically are allocated on disk.</p>
4806
4807<p>To illustrate how ImageMagick utilizes resource limits, consider a typical
4808image resource request.  First, ImageMagick tries to allocate the pixels in
4809memory.  The request might be denied if the resource request exceeds the
4810<code>memory</code> limit or if the system does not honor the request.  If
4811a memory request is not honored, the pixels are allocated to disk and the file
4812is memory-mapped. However, if the allocation request exceeds the
4813<code>map</code> limit, the resource allocation goes to disk. In all cases, if
4814the resource request exceeds the <code>area</code> limit, the pixels are
4815automagically cached to disk. If the disk has a hard limit, the program
4816fails.</p>
4817
4818<p>In most cases you simply do not need to concern yourself with resource
4819limits.  ImageMagick chooses reasonable defaults and most images do not tax
4820your computer resources.  Where limits do come in handy is when you process
4821images that are large or on shared systems where ImageMagick can consume all
4822or most of the available memory. In this case, the ImageMagick workflow slows
4823other processes or, in extreme cases, brings the system to a halt.  Under
4824these circumstances, setting limits give some assurances that the ImageMagick
4825workflow will not interfere with other concurrent uses of the computer.  For
4826example, assume you have a web interface that processes images uploaded from
4827the Internet.  To assure ImageMagick does not exceed 10MiB of memory you can
4828simply set the area limit to 10MiB:</p>
4829
4830<pre class="highlight"><code>-limit area 10MB
4831</code></pre>
4832
4833<p>Now whenever a large image is processed, the pixels are automagically
4834cached to disk instead of memory.  This of course implies that large images
4835typically process very slowly, simply because pixel processing in memory can
4836be an order of magnitude faster than on disk.  Because your web site users
4837might inadvertently upload a huge image to process, you should set a disk
4838limit as well:</p>
4839
4840<pre class="highlight"><code>-limit area 10MB -limit disk 500MB
4841</code></pre>
4842
4843<p>Here ImageMagick stops processing if an image requires more than 500MB of disk storage.</p>
4844
4845<p>In addition to command-line resource limit option, resources can be set
4846with <a href="../www/resources.html#environment" >environment variables</a>. Set the
4847environment variables <code>MAGICK_AREA_LIMIT</code>,
4848<code>MAGICK_DISK_LIMIT</code>, <code>MAGICK_FILE_LIMIT</code>,
4849<code>MAGICK_MEMORY_LIMIT</code>, <code>MAGICK_MAP_LIMIT</code>,
4850<code>MAGICK_THREAD_LIMIT</code>, <code>MAGICK_TIME_LIMIT</code> for limits of
4851image area, disk space, open files, heap memory, memory map, number of threads
4852of execution, and maximum elapsed time in seconds respectively.</p>
4853
4854<p> Inquisitive users can try adding <a href="command-line-options.html#debug">-debug cache</a> to
4855their commands and then scouring the generated output for references to the
4856pixel cache, in order to determine how the pixel cache was allocated and how
4857resources were consumed. Advanced Unix/Linux users can pipe that output
4858through <code>grep memory|open|destroy|disk</code> for more readable sifting.
4859</p>
4860
4861<p>For more about ImageMagick's use of resources, see the section <b>Cache
4862Storage and Resource Requirements</b> on the <a href="../www/architecture.html#cache
4863">Architecture</a> page.  </p>
4864
4865<div style="margin: auto;">
4866  <h3><a class="anchor" id="linear-stretch"></a>-linear-stretch <var>black-point</var><br />-linear-stretch <var>black-point</var>{x<var>white-point</var>}{<var>%</var>}</h3>
4867</div>
4868
4869<p class="magick-description">Linear with saturation stretch.</p>
4870
4871<p>This is very similar to <a href="command-line-options.html#contrast-stretch" >-contrast-stretch</a>,
4872and uses a 'histogram bin' to determine the range of color values that needs to
4873be stretched.  However it then stretches those colors using the <a
4874href="command-line-options.html#level" >-level</a> operator.</p>
4875
4876<p>As such while the initial determination may have 'binning' round off
4877effects, the image colors are stretched mathematically, rather than using the
4878histogram bins.  This makes the operator more accurate. </p>
4879
4880<p>note however that a <a href="command-line-options.html#linear-stretch" >-linear-stretch</a> of
4881'<code>0</code>' does nothing, while a value of '<code>1</code>' does a near
4882perfect stretch of the color range. </p>
4883
4884<p>See also <a href="command-line-options.html#auto-level" >-auto-level</a> for a 'perfect'
4885normalization of mathematical images. </p>
4886
4887<p>This operator is under review for re-development. </p>
4888
4889
4890<div style="margin: auto;">
4891  <h3><a class="anchor" id="linewidth"></a>-linewidth</h3>
4892</div>
4893
4894<p class="magick-description">The line width for subsequent draw operations.</p>
4895
4896<div style="margin: auto;">
4897  <h3><a class="anchor" id="liquid-rescale"></a>-liquid-rescale <var>geometry</var></h3>
4898</div>
4899
4900<p class="magick-description">Rescale image with seam-carving.</p>
4901
4902<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
4903
4904<div style="margin: auto;">
4905  <h3><a class="anchor" id="list"></a>-list <var>type</var></h3>
4906</div>
4907
4908<p class="magick-description">Print a list of supported arguments for various options or settings.  Choose from these list types:</p>
4909
4910<pre class="pre-scrollable highlight"><code>
4911Align
4912Alpha
4913Boolean
4914Cache
4915Channel
4916Class
4917ClipPath
4918Coder
4919Color
4920Colorspace
4921Command
4922Complex
4923Compose
4924Compress
4925Configure
4926DataType
4927Debug
4928Decoration
4929Delegate
4930Direction
4931Dispose
4932Distort
4933Dither
4934Endian
4935Evaluate
4936FillRule
4937Filter
4938Font
4939Format
4940Function
4941Gravity
4942Intensity
4943Intent
4944Interlace
4945Interpolate
4946Kernel
4947Layers
4948LineCap
4949LineJoin
4950List
4951Locale
4952LogEvent
4953Log
4954Magic
4955Method
4956Metric
4957Mime
4958Mode
4959Morphology
4960Module
4961Noise
4962Orientation
4963PixelIntensity
4964Policy
4965PolicyDomain
4966PolicyRights
4967Preview
4968Primitive
4969QuantumFormat
4970Resource
4971SparseColor
4972Statistic
4973Storage
4974Stretch
4975Style
4976Threshold
4977Type
4978Units
4979Validate
4980VirtualPixel
4981</code></pre>
4982
4983<p>These lists vary depending on your version of ImageMagick. Use "<code>-list
4984list</code>" to get a complete listing of all the "<code>-list</code>" arguments
4985available:</p>
4986
4987<pre class="highlight"><code>magick identify -list list
4988</code></pre>
4989
4990<div style="margin: auto;">
4991  <h3><a class="anchor" id="log"></a>-log <var>string</var></h3>
4992</div>
4993
4994<p class="magick-description">Specify format for debug log.</p>
4995
4996<p>This option specifies the format for the log printed when the <a
4997href="command-line-options.html#debug">-debug</a> option is active.</p>
4998
4999<p>You can display the following components by embedding special format
5000characters:</p>
5001
5002<div class="pre-scrollable highlight">
5003<dl class="row">
5004<dt class="col-md-4">%d</dt><dd class="col-md-8">domain</dd>
5005<dt class="col-md-4">%e</dt><dd class="col-md-8">event</dd>
5006<dt class="col-md-4">%f</dt><dd class="col-md-8">function</dd>
5007<dt class="col-md-4">%l</dt><dd class="col-md-8">line</dd>
5008<dt class="col-md-4">%m</dt><dd class="col-md-8">module</dd>
5009<dt class="col-md-4">%p</dt><dd class="col-md-8">process ID</dd>
5010<dt class="col-md-4">%r</dt><dd class="col-md-8">real CPU time</dd>
5011<dt class="col-md-4">%t</dt><dd class="col-md-8">wall clock time</dd>
5012<dt class="col-md-4">%u</dt><dd class="col-md-8">user CPU time</dd>
5013<dt class="col-md-4">%%</dt><dd class="col-md-8">percent sign</dd>
5014<dt class="col-md-4">\n</dt><dd class="col-md-8">newline</dd>
5015<dt class="col-md-4">\r</dt><dd class="col-md-8">carriage return</dd>
5016</dl>
5017</div>
5018
5019<p>For example:</p>
5020
5021<pre class="highlight"><code>magick -debug coder -log "%u %m:%l %e" in.gif out.png
5022</code></pre>
5023
5024<p>The default behavior is to print all of the components.</p>
5025
5026<div style="margin: auto;">
5027  <h3><a class="anchor" id="loop"></a>-loop <var>iterations</var></h3>
5028</div>
5029
5030<p class="magick-description">Add Netscape loop extension to your GIF animation.</p>
5031
5032<p>Set iterations to zero to repeat the animation an infinite number of times,
5033otherwise the animation repeats itself up to <var>iterations</var>
5034times.</p>
5035
5036<div style="margin: auto;">
5037  <h3><a class="anchor" id="lowlight-color"></a>-lowlight-color <var>color</var></h3>
5038</div>
5039
5040<p class="magick-description">When comparing images, de-emphasize pixel differences with this color.</p>
5041
5042<div style="margin: auto;">
5043  <h3><a class="anchor" id="magnify"></a>-magnify</h3>
5044</div>
5045
5046<p class="magick-description">Double or triple the size of the image with pixel art scaling. Specify an alternative scaling method with <code>-define magnify:method=<var>method</var></code> Choose from these methods: <code>eagle2X, eagle3X, eagle3XB, epb2X, fish2X, hq2X,  scale2X, scale3X, xbr2X</code>.  The default is scale2X.</p>
5047
5048
5049<div style="margin: auto;">
5050  <h3><a class="anchor" id="map"></a>-map <var>type</var></h3>
5051</div>
5052
5053<p class="magick-description">Display image using this <var>type</var>.</p>
5054
5055<p>Choose from these <var>Standard Colormap</var> types:</p>
5056
5057<pre class="highlight"><code>best
5058default
5059gray
5060red
5061green
5062blue
5063</code></pre>
5064
5065<p>The <var>X server</var> must support the <var>Standard
5066Colormap</var> you choose, otherwise an error occurs.  Use <code>list</code> as
5067the type and <code>display</code> searches the list of colormap types in
5068<code>top-to-bottom</code> order until one is located. See <var>xstdcmap(1)</var> for one way of creating Standard Colormaps.</p>
5069
5070
5071<div style="margin: auto;">
5072  <h3><a class="anchor" id="map_stream_"></a>-map <var>components</var></h3>
5073</div>
5074
5075<p class="magick-description">Pixel map.</p>
5076
5077<p>Here are the valid components of a map:</p>
5078
5079<div class="pre-scrollable highlight">
5080<dl class="row">
5081<dt class="col-md-4">r</dt><dd class="col-md-8">  red pixel component</dd>
5082<dt class="col-md-4">g</dt><dd class="col-md-8">  green pixel component</dd>
5083<dt class="col-md-4">b</dt><dd class="col-md-8">  blue pixel component</dd>
5084<dt class="col-md-4">a</dt><dd class="col-md-8">  alpha pixel component (0 is transparent)</dd>
5085<dt class="col-md-4">o</dt><dd class="col-md-8">  opacity pixel component (0 is opaque)</dd>
5086<dt class="col-md-4">i</dt><dd class="col-md-8">  grayscale intensity pixel component</dd>
5087<dt class="col-md-4">c</dt><dd class="col-md-8">  cyan pixel component</dd>
5088<dt class="col-md-4">m</dt><dd class="col-md-8">  magenta pixel component</dd>
5089<dt class="col-md-4">y</dt><dd class="col-md-8">  yellow pixel component</dd>
5090<dt class="col-md-4">k</dt><dd class="col-md-8">  black pixel component</dd>
5091<dt class="col-md-4">p</dt><dd class="col-md-8">  pad component (always 0)</dd>
5092</dl>
5093</div>
5094
5095<p>You can specify as many of these components as needed in any order (e.g.
5096bgr).  The components can repeat as well (e.g. rgbr).</p>
5097
5098
5099<div style="margin: auto;">
5100  <h3><a class="anchor" id="mattecolor"></a>-mattecolor <var>color</var></h3>
5101</div>
5102
5103<p class="magick-description">Specify the color to be used with the <a href="command-line-options.html#frame">-frame</a> option.</p>
5104
5105<p>The color is specified using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
5106
5107<p>The default matte color is <code>#BDBDBD</code>, <span
5108style="background-color: #bdbdbd;">this shade of gray</span>.</p>
5109
5110<div style="margin: auto;">
5111  <h3><a class="anchor" id="maximum"></a>-maximum</h3>
5112</div>
5113
5114<p class="magick-description">Return the maximum intensity of an image sequence.</p>
5115
5116<p>Select the 'maximum' value from all the surrounding pixels. </p>
5117
5118<p>This is legacy option from the <a href="command-line-options.html#statistic" >method</a> of the same
5119name. </p>
5120
5121<div style="margin: auto;">
5122  <h3><a class="anchor" id="median"></a>-median <var>geometry</var></h3>
5123</div>
5124
5125<p class="magick-description">Apply a median filter to the image.</p>
5126
5127<p>Select the 'middle' value from all the surrounding pixels. </p>
5128
5129<p>This is legacy option from the <a href="command-line-options.html#statistic" >method</a> of the same
5130name. </p>
5131
5132<div style="margin: auto;">
5133  <h3><a class="anchor" id="mean-shift"></a>-mean-shift <var>width</var>x<var>height</var>{<var>+distance</var>{%}</h3>
5134</div>
5135
5136<p class="magick-description">Image noise removal and color reduction/segmentation (e.g. -mean-shift 7x7+10%).</p>
5137
5138<p><var>width</var>x<var>height</var> is the window size and <var>distance</var> is the color distance measured in the range 0 to 1 or 0 to 100%</p>
5139
5140<p>The mean shift algorithm is iterative and thus slower the larger the window size. For each pixel, it gets all the pixels in the window centered at the pixel and excludes those that are outside the <var>radius=sqrt((width-1)(height-1)/4)</var> surrounding the pixel. From those pixels, it finds which of them are within the specified squared color distance from the current mean. It then computes a new x,y centroid from those coordinates and a new mean. This new x,y centroid is used as the center for a new window. This process is iterated until it converges and the final mean is then used to replace the original pixel value. It repeats this process for the next pixel, etc, until it processes all pixels in the image. Results are better when using other colorspaces rather than RGB. Recommend YIQ, YUV or YCbCr, which seem to give equivalent results.</p>
5141
5142<div style="margin: auto;">
5143  <h3><a class="anchor" id="metric"></a>-metric <var>type</var></h3>
5144</div>
5145
5146<p class="magick-description">Output to STDERR a measure of the differences between images according to the <var>type</var> given metric.</p>
5147
5148<p>Choose from:</p>
5149
5150<div class="pre-scrollable highlight">
5151<dl class="row">
5152<dt class="col-md-4">AE</dt><dd class="col-md-8">    absolute error count, number of different pixels (-fuzz affected)</dd>
5153<dt class="col-md-4">DSSIM</dt><dd class="col-md-8">  structural dissimilarity index</dd>
5154<dt class="col-md-4">FUZZ</dt><dd class="col-md-8">  mean color distance</dd>
5155<dt class="col-md-4">MAE</dt><dd class="col-md-8">   mean absolute error (normalized), average channel error distance</dd>
5156<dt class="col-md-4">MEPP</dt><dd class="col-md-8">  mean error per pixel (normalized mean error, normalized peak error)</dd>
5157<dt class="col-md-4">MSE</dt><dd class="col-md-8">   mean error squared, average of the channel error squared</dd>
5158<dt class="col-md-4">NCC</dt><dd class="col-md-8">   normalized cross correlation</dd>
5159<dt class="col-md-4">PAE</dt><dd class="col-md-8">   peak absolute (normalized peak absolute)</dd>
5160<dt class="col-md-4">PHASH</dt><dd class="col-md-8"> perceptual hash for the sRGB and HCLp colorspaces.  Specify an alternative colorspace with <code>-define phash:colorspaces=<var>colorspace,colorspace,...</var></code></dd>
5161<dt class="col-md-4">PSNR</dt><dd class="col-md-8">  peak signal to noise ratio</dd>
5162<dt class="col-md-4">RMSE</dt><dd class="col-md-8">  root mean squared (normalized root mean squared)</dd>
5163<dt class="col-md-4">SSIM</dt><dd class="col-md-8">  structural similarity index</dd>
5164</dl>
5165</div>
5166
5167<p>Control the '<code>AE</code>', or absolute count of pixels that are different,
5168with the <a href="command-line-options.html#fuzz" >-fuzz</a> factor (ignore pixels which
5169only changed by a small amount).  Use '<code>PAE</code>' to find the
5170size of the <a href="command-line-options.html#fuzz" >-fuzz</a> factor needed to make all pixels
5171'similar', while '<code>MAE</code>' determines the factor needed
5172for about half the pixels to be similar. </p>
5173
5174<p>The <code>MEPP</code> metric returns three different metrics
5175('<code>MAE</code>', '<code>MAE</code>' normalized, and '<code>PAE</code>'
5176normalized) from a single comparison run. </p>
5177
5178<p>The <code>SSIM</code> and <code>DSSIM</code> metrics respect these defines:
5179<code>-define compare:ssim-radius</code>, <code>-define compare:ssim-sigma</code>,
5180<code>-define compare:ssim-k1</code>, and <code>-define compare:ssim-k2</code>.</p>
5181
5182<p>To print a complete list of metrics, use the <a href="command-line-options.html#list">-list
5183metric</a> option.</p>
5184
5185
5186<div style="margin: auto;">
5187  <h3><a class="anchor" id="minimum"></a>-minimum</h3>
5188</div>
5189
5190<p class="magick-description">Return the minimum intensity of an image sequence.</p>
5191
5192<p>Select the 'minimal' value from all the surrounding pixels. </p>
5193
5194<p>This is legacy option from the <a href="command-line-options.html#statistic" >method</a> of the same
5195name. </p>
5196
5197
5198
5199<div style="margin: auto;">
5200  <h3><a class="anchor" id="mode"></a>-mode <var>geometry</var></h3>
5201</div>
5202
5203<p class="magick-description">Make each pixel the \'predominant color\' of the neighborhood.'</p>
5204
5205<div style="margin: auto;">
5206  <h3>-mode <var>value</var></h3>
5207</div>
5208
5209<p class="magick-description">Mode of operation.</p>
5210
5211<p>Choose the <var>value</var> from these styles: <code>Frame,
5212Unframe, or Concatenate</code></p>
5213
5214<p>Use the <a href="command-line-options.html#list" >-list</a> option with a '<code>Mode</code>' argument
5215for a list of <a href="command-line-options.html#mode" >-mode</a> arguments available in your
5216ImageMagick installation.</p>
5217
5218
5219<div style="margin: auto;">
5220  <h3><a class="anchor" id="modulate"></a>-modulate <var>brightness</var>[,<var>saturation</var>,<var>hue</var>]</h3>
5221</div>
5222
5223<p class="magick-description">Vary the <var>brightness</var>, <var>saturation</var>, and <var>hue</var> of an image.</p>
5224
5225<p>The arguments are given as a percentages of variation. A value of 100 means
5226no change, and any missing values are taken to mean 100.</p>
5227
5228<p>The <var>brightness</var> is a multiplier of the overall
5229brightness of the image, so 0 means pure black, 50 is half as bright, 200 is
5230twice as bright. To invert its meaning <a href="command-line-options.html#negate">-negate</a> the image
5231before and after. </p>
5232
5233<p>The <var>saturation</var> controls the amount of color in an
5234image. For example, 0 produce a grayscale image, while a large value such as
5235200 produce a very colorful, 'cartoonish' color.</p>
5236
5237<p>The <var>hue</var> argument causes a "rotation" of the colors
5238within the image by the amount specified. For example, 50 results in
5239a counter-clockwise rotation of 90, mapping red shades to purple, and so on.
5240A value of either 0 or 200 results in a complete 180 degree rotation of the
5241image. Using a value of 300 is a 360 degree rotation resulting in no change to
5242the original image. </p>
5243
5244<p>For example, to increase the color brightness by 20% and decrease the color
5245saturation by 10% and leave the hue unchanged, use <a
5246href="command-line-options.html#modulate">-modulate 120,90</a>.</p>
5247
5248<p>Use <a href="command-line-options.html#set">-set</a> attribute of '<code
5249>option:modulate:colorspace</code>' to specify which colorspace to
5250modulate.  Choose from <code>HCL</code>, <code>HCLp</code>, <code>HSB</code>, <code>HSI</code>, <code>HSL</code> (the default), <code>HSV</code>, <code>HWB</code>, or <code>LCH</code> (LCHuv).  For example,</p>
5251
5252<pre class="highlight"><code>magick image.png -set option:modulate:colorspace hsb -modulate 120,90 modulate.png
5253</code></pre>
5254
5255<div style="margin: auto;">
5256  <h3><a class="anchor" id="moments"></a>-moments</h3>
5257</div>
5258
5259<p class="magick-description">Report image moments and perceptual hash.</p>
5260
5261
5262<div style="margin: auto;">
5263  <h3><a class="anchor" id="monitor"></a>-monitor</h3>
5264</div>
5265
5266<p class="magick-description">Monitor progress.</p>
5267
5268
5269<div style="margin: auto;">
5270  <h3><a class="anchor" id="monochrome"></a>-monochrome</h3>
5271</div>
5272
5273<p class="magick-description">Transform the image to black and white.</p>
5274
5275<div style="margin: auto;">
5276  <h3><a class="anchor" id="morph"></a>-morph <var>frames</var></h3>
5277</div>
5278
5279<p class="magick-description">Morphs an image sequence.</p>
5280
5281<p>Both the image pixels and size are linearly interpolated to give the
5282appearance of a metamorphosis from one image to the next, over all the images
5283in the current image list. The added images are the equivalent of a <a
5284href="command-line-options.html#blend">-blend</a> composition. The <var>frames</var>
5285argument determine how many images to interpolate between each image. </p>
5286
5287
5288<div style="margin: auto;">
5289  <h3><a class="anchor" id="morphology"></a>-morphology</h3>
5290  <h3>-morphology <var>method</var>  <var>kernel</var></h3>
5291</div>
5292
5293<p class="magick-description">Apply a morphology method to the image.</p>
5294
5295<p>See <a href="https://legacy.imagemagick.org/Usage/morphology/" >IM Usage Examples, Morphology</a>. </p>
5296
5297
5298<div style="margin: auto;">
5299  <h3><a class="anchor" id="mosaic"></a>-mosaic</h3>
5300</div>
5301
5302<p class="magick-description">An simple alias for the <a href="command-line-options.html#layers" >-layers</a> method "mosaic"</p>
5303
5304
5305<div style="margin: auto;">
5306  <h3><a class="anchor" id="motion-blur"></a>-motion-blur <var>radius</var><br />-motion-blur <var>radius</var>{x<var>sigma</var>}+<var>angle</var></h3>
5307</div>
5308
5309<p class="magick-description">Simulate motion blur.</p>
5310
5311<p>Blur with the given radius, standard deviation (sigma), and angle.   The
5312angle given is the angle toward which the image is blurred.  That is the
5313direction people would consider the object is coming from. </p>
5314
5315<p>Note that the blur is not uniform distribution, giving the motion a
5316definite sense of direction of movement. </p>
5317
5318<p>The <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting will determine how
5319pixels which are outside the image proper are blurred into the final result.
5320</p>
5321
5322<div style="margin: auto;">
5323  <h3><a class="anchor" id="name"></a>-name</h3>
5324</div>
5325
5326<p class="magick-description">Name an image.</p>
5327<div style="margin: auto;">
5328  <h3><a class="anchor" id="negate"></a>-negate</h3>
5329</div>
5330
5331<p class="magick-description">Replace each pixel with its complementary color.</p>
5332
5333<p>The red, green, and blue intensities of an image are negated. White becomes
5334black, yellow becomes blue, etc.  Use <a href="command-line-options.html#negate">+negate</a> to only
5335negate the grayscale pixels of the image.</p>
5336
5337<div style="margin: auto;">
5338  <h3><a class="anchor" id="noise"></a>-noise <var>geometry</var><br/>
5339  +noise <var>type</var></h3>
5340</div>
5341
5342<p class="magick-description">Add or reduce noise in an image.</p>
5343
5344<p>The principal function of noise peak elimination filter is to smooth the
5345objects within an image without losing edge information and without creating
5346undesired structures.  The central idea of the algorithm is to replace a pixel
5347with its next neighbor in value within a pixel window, if this pixel has been
5348found to be noise. A pixel is defined as noise if and only if this pixel is
5349a maximum or minimum within the pixel window.</p>
5350
5351<p>Use <code><a href="command-line-options.html#noise">-noise</a> <var>radius</var></code> to
5352specify the width of the neighborhood when reducing noise.  This is equivalent
5353to using a <code><a href="command-line-options.html#statistic" >-statistic</a> NonPeak</code> operation,
5354which should be used in preference.</p>
5355
5356<p>Use <a href="command-line-options.html#noise">+noise</a> followed by a noise <var>type</var> to add noise to an image. Choose from these noise
5357types:</p>
5358
5359<pre class="highlight"><code>Gaussian
5360Impulse
5361Laplacian
5362Multiplicative
5363Poisson
5364Random
5365Uniform
5366</code></pre>
5367
5368<p>The amount of noise added can be controlled by the <code><a
5369href="command-line-options.html#attenuate" >-attenuate</a></code> setting. If unset the value is
5370equivalent to 1.0, or a maximum noise addition.</p>
5371
5372<p>Note that Random will replace the image with noise rather than add noise to the image. Use Uniform, if you wish to add random noise to the image.</p>
5373
5374<p>To print a complete list of noises, use the <a href="command-line-options.html#list">-list noise</a> option.</p>
5375
5376<p>Also see the <a href="command-line-options.html#evaluate">-evaluate</a> noise functions that allows
5377the use of a controlling value to specify the amount of noise that should be
5378added to an image. </p>
5379
5380
5381<div style="margin: auto;">
5382  <h3><a class="anchor" id="normalize"></a>-normalize</h3>
5383</div>
5384
5385<p class="magick-description">Increase the contrast in an image by <var>stretching</var> the range of intensity values.</p>
5386
5387<p>The intensity values are stretched to cover the entire range of possible
5388values. While doing so, black-out at most <var>2%</var> of the pixels and
5389white-out at most <var>1%</var> of the pixels.</p>
5390
5391<p>Note that as of ImageMagick 6.4.7-0, <a href="command-line-options.html#normalize" >-normalize</a>
5392is equivalent to <a href="command-line-options.html#contrast-stretch" >-contrast-stretch 2%x1%</a>.
5393(Before this version, it was equivalent to <a href="command-line-options.html#contrast-stretch"
5394>-contrast-stretch 2%x99%</a>).</p>
5395
5396<p>All the channels are normalized in concert by the same amount so as to
5397preserve color integrity, when the default <a href="command-line-options.html#channel" >+channel</a>
5398setting is in use.  Specifying any other <a href="command-line-options.html#channel" >-channel</a>
5399setting will normalize the RGB channels independently.</p>
5400
5401<p>See  <a href="command-line-options.html#contrast-stretch" >-contrast-stretch</a> for more details.
5402Also see <a href="command-line-options.html#auto-level" >-auto-level</a> for a 'perfect' normalization
5403that is better suited to mathematically generated images. </p>
5404
5405<p>This operator is under review for re-development. </p>
5406
5407
5408<div style="margin: auto;">
5409  <h3><a class="anchor" id="opaque"></a>-opaque <var>color</var></h3>
5410</div>
5411
5412<p class="magick-description">Change this color to the fill color within the image.</p>
5413
5414<p>The <var>color</var> argument is defined using the format
5415described under the <a href="command-line-options.html#fill" >-fill</a> option.  The <a href="command-line-options.html#fuzz"
5416>-fuzz</a> setting can be used to match and replace colors similar to the one
5417given.</p>
5418
5419<p>Use <a href="command-line-options.html#opaque">+opaque</a> to paint any pixel that does not match
5420the target color. </p>
5421
5422<p>The <a href="command-line-options.html#transparent">-transparent</a>  operator is exactly the same
5423as <a href="command-line-options.html#opaque" >-opaque</a> but replaces the matching color with
5424transparency rather than the current <a href="command-line-options.html#fill">-fill</a> color setting.
5425To ensure that it can do this it also ensures that the image has an alpha
5426channel enabled, as per "<code><a href="command-line-options.html#alpha" >-alpha</a> set</code>", for
5427the new transparent colors, and does not require you to modify the <a
5428href="command-line-options.html#channel">-channel</a> to enable alpha channel handling. </p>
5429
5430
5431<div style="margin: auto;">
5432  <h3><a class="anchor" id="ordered-dither"></a>-ordered-dither <var>threshold_map</var>{,<var>level</var>...}</h3>
5433</div>
5434
5435<p class="magick-description">Dither the image using a pre-defined  ordered dither <var>threshold map</var> specified, and a uniform color map with the
5436given number of <var>levels</var> per color channel.</p>
5437
5438<p>You can choose from these standard threshold maps:</p>
5439
5440<pre class="pre-scrollable highlight"><code>
5441threshold   1x1   Threshold 1x1 (non-dither)
5442checks      2x1   Checkerboard 2x1 (dither)
5443o2x2        2x2   Ordered 2x2 (dispersed)
5444o3x3        3x3   Ordered 3x3 (dispersed)
5445o4x4        4x4   Ordered 4x4 (dispersed)
5446o8x8        8x8   Ordered 8x8 (dispersed)
5447h3x4a       4x1   Halftone 4x4 (angled)
5448h6x6a       6x1   Halftone 6x6 (angled)
5449h8x8a       8x1   Halftone 8x8 (angled)
5450h3x4o             Halftone 4x4 (orthogonal)
5451h6x6o             Halftone 6x6 (orthogonal)
5452h8x8o             Halftone 8x8 (orthogonal)
5453h16x16o           Halftone 16x16 (orthogonal)
5454c5x5b       c5x5  Circles 5x5 (black)
5455c5x5w             Circles 5x5 (white)
5456c6x6b       c6x6  Circles 6x6 (black)
5457c6x6w             Circles 6x6 (white)
5458c7x7b       c7x7  Circles 7x7 (black)
5459c7x7w             Circles 7x7 (white)
5460</code></pre>
5461
5462<p> The <code>threshold</code> generated a simple 50% threshold of the image.
5463This could be used with <var >level</var> to do the equivalent of <a
5464href="command-line-options.html#posterize" >-posterize</a> to reduce an image to basic primary colors.
5465</p>
5466
5467<p>The <code>checks</code> pattern produces a 3 level checkerboard  dither
5468pattern. That is a grayscale will become a pattern of solid black, solid
5469white, and  mid-tone colors into a checkerboard pattern of black and white.
5470</p>
5471
5472<p>You can define your own <var >threshold map</var> for ordered
5473dithering and halftoning your images, in either personal or system
5474<code>thresholds.xml</code> XML file. See <a href="../www/resources.html" >Resources</a>
5475for more details of configuration files. </p>
5476
5477<p>To print a complete list of the thresholds that have been defined, use the
5478<a href="command-line-options.html#list" >-list threshold</a> option.</p>
5479
5480<p>Note that at this time the same threshold dithering map is used for all
5481color channels, no attempt is made to offset or rotate the map for different
5482channels is made, to create an offset printing effect. Also as the maps are
5483simple threshold levels, the halftone and circle maps will create incomplete
5484circles along the edges of a colored area. Also all the effects are purely
5485on/off boolean effects, without anti-aliasing to make the circles smooth
5486looking. Large dots can be made to look better with a small amount of blurring
5487after being created. </p>
5488
5489
5490<div style="margin: auto;">
5491  <h3><a class="anchor" id="orient"></a>-orient <var>image orientation</var></h3>
5492</div>
5493
5494<p class="magick-description">Specify orientation of a digital camera image.</p>
5495
5496<p>Choose from these orientations:</p>
5497
5498<pre class="highlight"><code>bottom-left    right-top
5499bottom-right   top-left
5500left-bottom    top-right
5501left-top       undefined
5502right-bottom
5503</code></pre>
5504
5505<p>To print a complete list of orientations, use the <a href="command-line-options.html#list" >-list
5506orientation</a> option.</p>
5507
5508
5509<div style="margin: auto;">
5510  <h3><a class="anchor" id="page"></a>-page <var>geometry</var><br/>
5511  -page <var>media</var>[<var>offset</var>][{<var>^!&lt;&gt;</var>}]<br/>
5512  +page
5513  </h3>
5514</div>
5515
5516<p class="magick-description">Set the size and location of an image on the larger virtual canvas.</p>
5517
5518<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
5519
5520<p>For convenience you can specify the page size using <var>media</var> (see below). Offsets can then be added as with other
5521<var>geometry</var> arguments (e.g. <a
5522href="command-line-options.html#page">-page</a> <code>Letter+43+43</code>).</p>
5523
5524<p>Use <var>media</var> as shorthand to specify the dimensions (<var>width</var>x<var>height</var>) of the <var>PostScript</var> page in dots per inch or a TEXT page in pixels.
5525The choices for paper sizes are: <code>4x6</code>, <code>5x7</code>, <code>7x9</code>, <code>8x10</code>, <code>9x11</code>, <code>9x12</code>, <code>10x13</code>, <code>10x14</code>, <code>11x17</code>, <code>4A0</code>, <code>2A0</code>, <code>a0</code>, <code>a1</code>, <code>a2</code>, <code>a3</code>, <code>a4</code>, <code>a4small</code>, <code>a5</code>, <code>a6</code>, <code>a7</code>, <code>a8</code>, <code>a9</code>, <code>a10</code>, <code>archa</code>, <code>archb</code>, <code>archC</code>, <code>archd</code>, <code>arche</code>, <code>b0</code>, <code>b1</code>, <code>b10</code>, <code>b2</code>, <code>b3</code>, <code>b4</code>, <code>b5</code>, <code>b6</code>, <code>b7</code>, <code>b8</code>, <code>b9</code>, <code>c0</code>, <code>c1</code>, <code>c2</code>, <code>c3</code>, <code>c4</code>, <code>c5</code>, <code>c6</code>, <code>c7</code>, <code>csheet</code>, <code>dsheet</code>, <code>esheet</code>, <code>executive</code>, <code>flsa</code>, <code>flse</code>, <code>folio</code>, <code>halfletter</code>, <code>isob0</code>, <code>isob1</code>, <code>isob10</code>, <code>isob2</code>, <code>isob3</code>, <code>isob4</code>, <code>isob5</code>, <code>isob6</code>, <code>isob7</code>, <code>isob8</code>, <code>isob9</code>, <code>jisb0</code>, <code>jisb1</code>, <code>jisb2</code>, <code>jisb3</code>, <code>jisb4</code>, <code>jisb5</code>, <code>jisb6</code>, <code>ledger</code>, <code>legal</code>, <code>letter</code>, <code>lettersmall</code>, <code>monarch</code>, <code>quarto</code>, <code>statement</code>, <code>tabloid</code>. To determine the cooresponding size in pixels at 72DPI, use this command for example:</p>
5526<pre class="highlight"><code>magick xc: -format "%[papersize:a4]" info:</code></pre>
5527
5528<p>This option is also used to place subimages when writing to a multi-image
5529format that supports offsets, such as GIF89 and MNG. When used for this
5530purpose the offsets are always measured from the top left corner of the canvas
5531and are not affected by the <a href="command-line-options.html#gravity">-gravity</a> option. To
5532position a GIF or MNG image, use <a href="command-line-options.html#page">-page</a><var>{+-}x{+-}y</var> (e.g.  -page +100+200). When writing to a MNG
5533file, a <a href="command-line-options.html#page">-page</a> option appearing ahead of the first image in
5534the sequence with nonzero width and height defines the width and height values
5535that are written in the <code>MHDR</code> chunk.  Otherwise, the MNG width and
5536height are computed from the bounding box that contains all images in the
5537sequence. When writing a GIF89 file, only the bounding box method is used to
5538determine its dimensions.</p>
5539
5540<p>For a PostScript page, the image is sized as in <a
5541href="command-line-options.html#geometry">-geometry</a> but positioned relative to the <var>lower
5542left-hand corner</var> of the page by {+-}<code>x</code><var>offset</var>{+-}<code>y</code> <var>offset</var>. Use <a
5543href="command-line-options.html#page">-page 612x792</a>, for example, to center the image within the
5544page. If the image size exceeds the PostScript page, it is reduced to fit the
5545page. The default gravity for the <a href="command-line-options.html#page">-page</a> option is <var>NorthWest</var>, i.e., positive <code>x</code> and <code>y</code> <var>offset</var> are measured rightward and downward from the top left
5546corner of the page, unless the <a href="command-line-options.html#gravity">-gravity</a> option is
5547present with a value other than <var>NorthWest</var>.</p>
5548
5549<p>The default page dimensions for a TEXT image is 612x792.</p>
5550
5551<p>This option is used in concert with <a href="command-line-options.html#density">-density</a>.</p>
5552
5553<p>Use <a href="command-line-options.html#page">+page</a> to remove the page settings for an image.</p>
5554
5555<div style="margin: auto;">
5556  <h3><a class="anchor" id="paint"></a>-paint <var>radius</var></h3>
5557</div>
5558
5559<p class="magick-description">Simulate an oil painting.</p>
5560
5561<p>Each pixel is replaced by the most frequent color in a circular
5562neighborhood whose width is specified with <var>radius</var>.</p>
5563
5564<div style="margin: auto;">
5565  <h3><a class="anchor" id="path"></a>-path <var>path</var></h3></div>
5566
5567<p class="magick-description">Write images to this path on disk.</p>
5568
5569<div style="margin: auto;">
5570  <h3><a class="anchor" id="pause_animate_"></a>-pause <var>seconds</var></h3>
5571</div>
5572
5573<p class="magick-description">Pause between animation loops</p>
5574
5575<p>Pause for the specified number of seconds before repeating the animation.</p>
5576
5577<div style="margin: auto;">
5578  <h3><a class="anchor" id="pause_import_"></a>-pause <var>seconds</var></h3>
5579</div>
5580
5581<p class="magick-description">Pause between snapshots.</p>
5582
5583<p>Pause for the specified number of seconds before taking the next snapshot.</p>
5584
5585<div style="margin: auto;">
5586  <h3><a class="anchor" id="perceptible"></a>-perceptible <var>epsilon</var></h3>
5587</div>
5588
5589<p class="magick-description">Set each pixel whose value is less than |<var>epsilon</var>| to <var>-epsilon</var> or <var>epsilon</var> (whichever is closer) otherwise the pixel value remains unchanged.</p>
5590
5591<div style="margin: auto;">
5592  <h3><a class="anchor" id="ping"></a>-ping</h3>
5593</div>
5594
5595<p class="magick-description">Efficiently determine these image characteristics: image number, the file name, the width and height of the image, whether the image is colormapped or not, the number of colors in the image, the number of bytes in the image, the format of the image (JPEG, PNM, etc.).  Use <code>+ping</code> to ensure accurate image properties.</p>
5596
5597<div style="margin: auto;">
5598  <h3><a class="anchor" id="pointsize"></a>-pointsize <var>value</var></h3>
5599</div>
5600
5601<p class="magick-description">Pointsize of the PostScript, OPTION1, or TrueType font.</p>
5602
5603<div style="margin: auto;">
5604  <h3><a class="anchor" id="polaroid"></a>-polaroid <var>angle</var></h3>
5605</div>
5606
5607<p class="magick-description">Simulate a Polaroid picture.</p>
5608
5609<p>Use <code>+polaroid</code> to rotate the image at a random angle between -15 and +15 degrees.</p>
5610
5611<div style="margin: auto;">
5612  <h3><a class="anchor" id="poly"></a>-poly <var>"wt,exp ..."</var></h3>
5613</div>
5614
5615<p class="magick-description">Combines multiple images according to a weighted sum of polynomials; one floating point weight (coefficient) and one floating point polynomial exponent (power) for each image expressed as comma separated pairs.</p>
5616
5617<p> The weights should typically be fractions between -1 and 1. But the sum of weights should be 1 or at least between 0 and 1 to avoid clamping in non-hdri mode at black and white.</p>
5618
5619<p>The exponents may be positive, negative or zero. A negative exponent is equivalent to 1 divided by the image raised to the corresponding positive exponent. A zero exponent always produces 1 scaled by quantumrange to white, i.e. wt*white, no matter what the image.</p>
5620
5621<p>The format is: <var>output = wt1*image1^exp1 + wt2*image2^exp2 </var>...</p>
5622
5623<p>Some simple uses are:</p>
5624<ul>
5625<li>A weighted sum of each image provided all weights add to unity and all exponents=1. If the weights are all equal to 1/(number of images), then this is equivalent to <a href="command-line-options.html#profile">-evaluate-sequence</a> <var>mean</var>.</li>
5626<li>The sum of squares of two or more images, provided the weights are equal (and sum to 1 to avoid clamping) and the exponents equal 2.</li>
5627</ul>
5628
5629<p>Note that one may add a constant color to the expression simply by using xc:somecolor for one of the images and specifying the desired weight and exponent equal to 0.</p>
5630
5631<p>Similarly one may add white to the expression by simply using null: (or xc:white) for one of the images with the appropriate weight and exponent equal to 0.</p>
5632
5633
5634<div style="margin: auto;">
5635  <h3><a class="anchor" id="posterize"></a>-posterize <var>levels</var></h3>
5636</div>
5637
5638<p class="magick-description">Reduce the image to a limited number of color levels per channel.</p>
5639
5640<p>Very low values of <var>levels</var>, e.g., 2, 3, 4, have the most
5641visible effect.</p>
5642
5643<div style="margin: auto;">
5644  <h3><a class="anchor" id="precision"></a>-precision <var>value</var></h3>
5645</div>
5646
5647<p class="magick-description">Set the maximum number of significant digits to be printed.</p>
5648
5649<div style="margin: auto;">
5650  <h3><a class="anchor" id="preview"></a>-preview <var>type</var></h3>
5651</div>
5652
5653<p class="magick-description">Image preview type.</p>
5654
5655<p>Use this option to affect the preview operation of an image (e.g.
5656<code>magick file.png -preview Gamma Preview:gamma.png</code>). Choose from
5657these previews:</p>
5658
5659<pre class="pre-scrollable highlight"><code>
5660AddNoise
5661Blur
5662Brightness
5663Charcoal
5664Despeckle
5665Dull
5666EdgeDetect
5667Gamma
5668Grayscale
5669Hue
5670Implode
5671JPEG
5672OilPaint
5673Quantize
5674Raise
5675ReduceNoise
5676Roll
5677Rotate
5678Saturation
5679Segment
5680Shade
5681Sharpen
5682Shear
5683Solarize
5684Spiff
5685Spread
5686Swirl
5687Threshold
5688Wave
5689</code></pre>
5690
5691<p>To print a complete list of previews, use the <a href="command-line-options.html#list">-list preview</a> option.</p>
5692
5693<p>The default preview is <code>JPEG</code>.</p>
5694
5695<div style="margin: auto;">
5696  <h3><a class="anchor" id="print"></a>-print <var>string</var></h3>
5697</div>
5698
5699<p class="magick-description">Interpret string and print to console.</p>
5700
5701<div style="margin: auto;">
5702  <h3><a class="anchor" id="process"></a>-process <var>command</var></h3>
5703</div>
5704
5705<p class="magick-description">Process the image with a custom image filter.</p>
5706
5707<p>The command arguments has the form <code>"module arg1 arg2 arg3 ...
5708argN"</code> where <code>module</code> is the name of the module to invoke (e.g.
5709"Analyze") and arg1 arg2 arg3 ... argN are an arbitrary number of arguments to
5710pass to the process module.</p>
5711
5712<div style="margin: auto;">
5713  <h3><a class="anchor" id="profile"></a>-profile <var>filename</var><br/>
5714  +profile <var>profile_name</var></h3>
5715</div>
5716
5717<p class="magick-description">Manage ICM, IPTC, or generic profiles in an image.</p>
5718
5719<p>Using <a href="command-line-options.html#profile">-profile</a> <var>filename</var> adds an
5720ICM (ICC color management), IPTC (newswire information), or a generic profile
5721to the image.</p>
5722
5723<p>Use <a href="command-line-options.html#profile">+profile <var>profile_name</var></a> to
5724remove the indicated profile. ImageMagick uses standard filename globbing, so
5725wildcard expressions may be used to remove more than one profile.  Here we
5726remove all profiles from the image except for the XMP profile:  <code>+profile
5727"!xmp,*"</code>. </p>
5728
5729<p>Use <code>magick identify -verbose</code> to find out which profiles are in the
5730image file. Use <a href="command-line-options.html#strip">-strip</a> to remove all profiles (and
5731comments).</p>
5732
5733<p>To extract a profile, the <a href="command-line-options.html#profile">-profile</a> option is not
5734used. Instead, simply write the file to an image format such as <var>APP1, 8BIM, ICM,</var> or <var>IPTC</var>.</p>
5735
5736<p>For example, to extract the Exif data (which is stored in JPEG files in the
5737<var>APP1</var> profile), use.</p>
5738
5739<p>Set <code>-define precision:highres-transform=true</code> to increase the transform precision.  Note, there is a slight performance penalty as the high-precision transform is floating point rather than unsigned.</p>
5740
5741<pre class="highlight"><code>magick cockatoo.jpg profile.exif
5742</code></pre>
5743
5744<p>It is important to note that results may depend on whether or not the
5745original image already has an included profile. Also, keep in mind that <a
5746href="command-line-options.html#profile">-profile</a> is an "operator" (as opposed to a "setting") and
5747therefore a conversion is made each time it is encountered, in order, in the
5748command-line. For instance, in the following example, if the original image is
5749CMYK with profile, a CMYK-CMYK-RGB conversion results.</p>
5750
5751<pre class="highlight"><code>magick CMYK.tif -profile "CMYK.icc" -profile "RGB.icc" RGB.tiff
5752</code></pre>
5753
5754<p>Furthermore, since ICC profiles are not necessarily symmetric, extra
5755conversion steps can yield unwanted results.  CMYK profiles are often very
5756asymmetric since they involve 3−&gt;4 and 4−&gt;3 channel mapping.
5757</p>
5758
5759<div style="margin: auto;">
5760  <h3><a class="anchor" id="quality"></a>-quality <var>value</var></h3>
5761</div>
5762
5763<p class="magick-description">JPEG/MIFF/PNG compression level.</p>
5764
5765<p>For the JPEG and MPEG image formats, quality is 1 (lowest image quality and
5766highest compression) to 100 (best quality but least effective compression).
5767The default is to use the estimated quality of your input image if it can
5768be determined, otherwise 92. When the quality is greater than 90, then the
5769chroma channels are not downsampled.
5770Use the <a href="command-line-options.html#sampling-factor">-sampling-factor</a> option to specify the
5771factors for chroma downsampling.</p>
5772
5773<p>For the JPEG-2000 image format, quality is mapped using a non-linear
5774equation to the compression ratio required by the Jasper library. This
5775non-linear equation is intended to loosely approximate the quality provided by
5776the JPEG v1 format. The default quality value 100, a request for non-lossy
5777compression.  A quality of 75 results in a request for 16:1 compression.</p>
5778
5779<p>For the MNG and PNG image formats, the quality value sets the zlib
5780compression level (quality / 10) and filter-type (quality % 10).  The default
5781PNG "quality" is 75, which means compression level 7 with adaptive PNG
5782filtering, unless the image has a color map, in which case it means
5783compression level 7 with no PNG filtering.</p>
5784
5785<p>For compression level 0 (quality value less than 10), the Huffman-only
5786strategy is used, which is fastest but not necessarily the worst
5787compression.</p>
5788
5789<p>If filter-type is 4 or less, the specified PNG filter-type is used for
5790all scanlines:</p>
5791
5792<div class="pre-scrollable highlight">
5793<dl class="row">
5794<dt class="col-md-4">0</dt><dd class="col-md-8">none</dd>
5795<dt class="col-md-4">1</dt><dd class="col-md-8">sub</dd>
5796<dt class="col-md-4">2</dt><dd class="col-md-8">up</dd>
5797<dt class="col-md-4">3</dt><dd class="col-md-8">average</dd>
5798<dt class="col-md-4">4</dt><dd class="col-md-8">Paeth</dd>
5799</dl>
5800</div>
5801
5802<p>If filter-type is 5, adaptive filtering is used when quality is greater
5803than 50 and the image does not have a color map, otherwise no filtering is
5804used.</p>
5805
5806<p>If filter-type is 6, adaptive filtering
5807with <var>minimum-sum-of-absolute-values</var> is used.</p>
5808
5809<p>Only if the output is MNG, if filter-type is 7, the LOCO color
5810transformation (intrapixel differencing) and adaptive filtering
5811with <var>minimum-sum-of-absolute-values</var> are used.</p>
5812
5813<p>If the filter-type is 8 the zlib Z_RLE compression strategy (or the
5814Z_HUFFMAN_ONLY strategy, when compression level is 0) is used with
5815adaptive PNG filtering.</p>
5816
5817<p>If the filter-type is 9 the zlib Z_RLE compression strategy (or the
5818Z_HUFFMAN_ONLY strategy, when compression level is 0) is used with
5819no PNG filtering.</p>
5820
5821<p>The quality setting has no effect on the appearance or signature of PNG
5822and MNG images, since the compression is always lossless.</p>
5823
5824<p>Not all combinations of compression level, strategy, and PNG filter type
5825can be obtained using the -quality option.  For more precise control,
5826you can use the PNG:compression-level=N, PNG:compression-strategy=N, and
5827PNG:compression-filter=N defines, respectively, instead.
5828See <a href="command-line-options.html#define">-define</a>. Values from the defines take precedence
5829over values from the -quality option.</p>
5830
5831<p>For further information, see
5832the <a href="http://www.w3.org/pub/WWW/TR">PNG</a> specification.</p>
5833
5834<p>For the MIFF and TIFF image formats, quality/10 is the <a href="command-line-options.html#compress">Zip/BZip</a> compression level, which is 0 (worst but fastest compression) to 9 (best but slowest). It has no effect on the image appearance, since the compression is always lossless.</p>
5835
5836<p>For the BPG image format, quality/2 is the actual BPG compression level (range from 0 to 51).</p>
5837
5838<div style="margin: auto;">
5839  <h3><a class="anchor" id="quantize"></a>-quantize <var>colorspace</var></h3>
5840</div>
5841
5842<p class="magick-description">Reduce colors using this colorspace.</p>
5843
5844<p>This setting defines the colorspace used to sort out and reduce the number
5845of colors needed by an image (for later dithering) by operators such as <a
5846href="command-line-options.html#colors" >-colors</a>, Note that color reduction also happens
5847automatically when saving images to color-limited image file formats, such as
5848GIF, and PNG8.</p>
5849
5850
5851<div style="margin: auto;">
5852  <h3><a class="anchor" id="quiet"></a>-quiet</h3>
5853</div>
5854
5855<p class="magick-description">Suppress all warning messages. Error messages are still reported.</p>
5856
5857<div style="margin: auto;">
5858  <h3><a class="anchor" id="radial-blur"></a>-radial-blur  <var>angle</var></h3>
5859</div>
5860
5861<p class="magick-description">Blur around the center of the image.</p>
5862
5863<p>Note that this is actually a rotational blur rather than a radial and as
5864such actually mis-named. </p>
5865
5866<p>The <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting will determine how
5867pixels which are outside the image proper are blurred into the final result.
5868</p>
5869
5870
5871<div style="margin: auto;">
5872  <h3><a class="anchor" id="raise"></a>-raise <var>thickness</var></h3>
5873</div>
5874
5875<p class="magick-description">Lighten or darken image edges.</p>
5876
5877<p>This will create a 3-D effect. Use <a href="command-line-options.html#raise">-raise</a> to create
5878a raised effect, otherwise use <a href="command-line-options.html#raise">+raise</a>.  </p>
5879
5880<p>Unlike the similar <a href="command-line-options.html#frame">-frame</a> option, <a
5881href="command-line-options.html#raise">-raise</a> does not alter the dimensions of the image.</p>
5882
5883<div style="margin: auto;">
5884  <h3><a class="anchor" id="random-threshold"></a>-random-threshold <var>low</var>x<var>high</var></h3>
5885</div>
5886
5887<p class="magick-description">Apply a random threshold to the image.</p>
5888
5889<div style="margin: auto;">
5890  <h3><a class="anchor" id="range-threshold"></a>-range-threshold <var>low-black</var>,<var>low-white</var>,<var>high-white</var>,<var>high-black</var></h3>
5891</div>
5892
5893<p class="magick-description">Perform either hard or soft thresholding within some range of values in an image.</p>
5894
5895<div style="margin: auto;">
5896  <h3><a class="anchor" id="read-mask"></a>-read-mask
5897<var>filename</var></h3>
5898</div>
5899
5900<p class="magick-description">Prevent updates to image pixels specified by the mask.</p>
5901
5902<p>This the same as using a mask used for composite masking operations, with
5903grayscale values causing blended updates of the image the mask is attached to.
5904</p>
5905
5906<p>Use <a href="command-line-options.html#read-mask">+read-mask</a> to remove the mask from images.</p>
5907
5908<p>Also see <a href="command-line-options.html#clip-mask">-clip-mask</a> which work in the same way,
5909but with strict boolean masking. </p>
5910
5911<div style="margin: auto;">
5912  <h3><a class="anchor" id="red-primary"></a>-red-primary <var>x,y</var></h3>
5913</div>
5914
5915<p class="magick-description">Set the red chromaticity primary point.</p>
5916
5917<div style="margin: auto;">
5918  <h3><a class="anchor" id="regard-warnings"></a>-regard-warnings</h3>
5919</div>
5920
5921<p class="magick-description">Pay attention to warning messages.</p>
5922
5923<p>This option causes some warnings in some image formats to be treated
5924as errors. </p>
5925
5926<div style="margin: auto;">
5927  <h3><a class="anchor" id="remap"></a>-remap <var>filename</var></h3>
5928</div>
5929
5930<p class="magick-description">Reduce the number of colors in an image to the colors used by this image.</p>
5931
5932<p>If the <a href="command-line-options.html#dither">-dither</a> setting is enabled (the default) then
5933the given colors are dithered over the image as necessary, otherwise the closest
5934color (in RGB colorspace) is selected to replace that pixel in the image. </p>
5935
5936<p>As a side effect of applying a <a href="command-line-options.html#remap">-remap</a> of colors across all
5937images in the current image sequence, all the images will have the same color
5938table.  That means that when saved to a file format such as GIF, it will use
5939that color table as a single common or global color table, for all the images,
5940without requiring extra local color tables. </p>
5941
5942<p>Use <a href="command-line-options.html#remap">+remap</a> to reduce all images in the current image
5943sequence to use a common color map over all the images. This equivalent to
5944appending all the images together (without extra background colors) and color
5945reducing those images using <a href="command-line-options.html#colors">-colors</a> with a 256 color
5946limit, then <a href="command-line-options.html#remap">-remap</a> those colors over the original list of
5947images. This ensures all the images follow a single color map. </p>
5948
5949<p>If the number of colors over all the images is less than 256, then <a
5950href="command-line-options.html#remap">+remap</a> should not perform any color reduction or dithering, as
5951no color changes are needed. In that case, its only effect is to force the use
5952of a global color table.  This recommended after using either <a
5953href="command-line-options.html#colors">-colors</a> or <a href="command-line-options.html#ordered-dither">-ordered-dither</a> to
5954reduce the number of colors in an animated image sequence. </p>
5955
5956<p>Note, the remap image colormap has at most 8-bits of precision. Deeper color maps are automagically coalesced with other colors to meet this requirement.</p>
5957
5958<div style="margin: auto;">
5959  <h3><a class="anchor" id="region"></a>-region <var>geometry</var></h3>
5960</div>
5961
5962<p class="magick-description">Set a region in which subsequent operations apply.</p>
5963
5964<p>The <var>x</var> and <var>y</var> offsets are treated
5965in the same manner as in <a href="command-line-options.html#crop">-crop</a>.</p>
5966
5967<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
5968
5969<p>Use <code>+region</code> to remove any previously set regions.</p>
5970
5971<div style="margin: auto;">
5972  <h3><a class="anchor" id="remote"></a>-remote</h3>
5973</div>
5974
5975<p class="magick-description">Perform a remote operation.</p>
5976
5977<p>The only command recognized is the name of an image file to load.</p>
5978
5979<p>If you have more than one <a href="display.html">display</a> application
5980running simultaneously, use the <a href="command-line-options.html#window"> window</a> option to
5981specify which application to control.</p>
5982
5983<div style="margin: auto;">
5984  <h3><a class="anchor" id="render"></a>-render</h3>
5985</div>
5986
5987<p class="magick-description">Render vector operations.</p>
5988
5989<p>Use <a href="command-line-options.html#render">+render</a> to turn off rendering vector operations.
5990This useful when saving the result to vector formats such as MVG or SVG.</p>
5991
5992<div style="margin: auto;">
5993<h3><a class="anchor" id="repage"></a>-repage <var>geometry</var></h3>
5994</div>
5995
5996<p class="magick-description">Adjust the canvas and offset information of the image.</p>
5997
5998<p>This option is like <a href="command-line-options.html#page">-page</a> but acts as an image operator
5999rather than a setting.  You can separately set the canvas size or the offset
6000of the image on that canvas by only providing those components. </p>
6001
6002<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
6003
6004<p>If a <code>!</code> flag is given the offset given is added to the existing
6005offset to move the image relative to its previous position. This useful for
6006animation sequences. </p>
6007
6008<p>A given a canvas size of zero such as '<code>0x0</code>' forces it to
6009recalculate the canvas size so the image (at its current offset) will appear
6010completely on that canvas (unless it has a negative offset).</p>
6011
6012<p>Use <a href="command-line-options.html#repage">+repage</a> to completely remove/reset the virtual
6013canvas meta-data from the images. </p>
6014
6015<p>The <a href="command-line-options.html#set">-set</a> '<code>page</code>' option can be used to
6016directly assign virtual canvas meta-data. </p>
6017
6018
6019<div style="margin: auto;">
6020  <h3><a class="anchor" id="resample"></a>-resample <var>horizontal</var>x<var>vertical</var></h3>
6021</div>
6022
6023<p class="magick-description">Resample image to specified horizontal and vertical resolution.</p>
6024
6025<p>Resize the image so that its rendered size remains the same as the original
6026at the specified target resolution. For example, if a 300 DPI image renders at
60273 inches by 2 inches on a 300 DPI device, when the image has been resampled to
602872 DPI, it will render at 3 inches by 2 inches on a 72 DPI device.  Note that
6029only a small number of image formats (e.g. JPEG, PNG, and TIFF) are capable of
6030storing the image resolution. For formats which do not support an image
6031resolution, the original resolution of the image must be specified via <a
6032href="command-line-options.html#density">-density</a> on the command line prior to specifying the
6033resample resolution.</p>
6034
6035<p>Note that Photoshop stores and obtains image resolution from a proprietary
6036embedded profile. If this profile exists in the image, then Photoshop will
6037continue to treat the image using its former resolution, ignoring the image
6038resolution specified in the standard file header.</p>
6039
6040<div style="margin: auto;">
6041  <h3><a class="anchor" id="resize"></a>-resize <var>geometry</var></h3>
6042</div>
6043
6044<p class="magick-description">Resize an image.</p>
6045
6046<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. Offsets, if present in the geometry string, are
6047ignored, and the <a href="command-line-options.html#gravity">-gravity</a> option has no effect.</p>
6048
6049<p>If the <a href="command-line-options.html#filter">-filter</a> option
6050or <code>-define filter:option=value</code> precedes the <a
6051href="command-line-options.html#resize">-resize</a> option, the image is resized with the specified
6052filter.</p>
6053
6054<p>Many image processing algorithms assume your image is in a linear-light
6055coding.  If your image is gamma-corrected, you can remove the nonlinear gamma
6056correction, apply the transform, then restore it like this:</p>
6057
6058<pre class="highlight"><code>magick portrait.jpg -gamma .45455 -resize 25% -gamma 2.2  \
6059  -quality 92 passport.jpg
6060</code></pre>
6061
6062<p>Note, some resampling functions are damped oscillations in approximation of a Sinc function.  As such, you may get negative lobes if your release of ImageMagick is HDRI-enabled.  To eliminate them, add <a href="command-line-options.html#clamp">-clamp</a> to your command-line.</p>
6063
6064<div style="margin: auto;">
6065  <h3><a class="anchor" id="respect-parentheses"></a>-respect-parentheses</h3>
6066</div>
6067
6068<p class="magick-description">Settings remain in effect until parenthesis boundary.</p>
6069
6070<div style="margin: auto;">
6071  <h3><a class="anchor" id="reverse"></a>-reverse</h3>
6072</div>
6073
6074<p class="magick-description">Reverse the order of images in the current image list.</p>
6075
6076
6077<div style="margin: auto;">
6078  <h3><a class="anchor" id="roll"></a>-roll {<var>+-</var>}<var>x</var>{<var>+-</var>}<var>y</var></h3>
6079</div>
6080
6081<p class="magick-description">Roll an image vertically or horizontally by the amount given.</p>
6082
6083<p>A negative <var>x</var> offset rolls the image right-to-left.
6084A negative <var>y</var> offset rolls the image bottom-to-top.</p>
6085
6086
6087<div style="margin: auto;">
6088  <h3><a class="anchor" id="rotate"></a>-rotate <var>degrees</var>{<var>&lt;</var>}{<var>&gt;</var>}</h3>
6089</div>
6090
6091<p class="magick-description">Apply Paeth image rotation (using shear operations) to the image.</p>
6092
6093<p>Use <code>&gt;</code> to rotate the image only if its width exceeds the
6094height. <code>&lt;</code> rotates the image <var>only</var> if its width is less
6095than the height. For example, if you specify <code>-rotate "-90&gt;"</code> and
6096the image size is 480x640, the image is not rotated. However, if the image is
6097640x480, it is rotated by -90 degrees. If you use <code>&gt;</code> or
6098<code>&lt;</code>, enclose it in quotation marks to prevent it from being
6099misinterpreted as a file redirection.</p>
6100
6101<p>Empty triangles in the corners, left over from rotating the image, are
6102filled with the <code>background</code> color. </p>
6103
6104<p>See also the <a href="command-line-options.html#distort">-distort</a> operator and specifically the
6105'<code>ScaleRotateTranslate</code>' distort method. </p>
6106
6107
6108<div style="margin: auto;">
6109  <h3><a class="anchor" id="sample"></a>-sample <var>geometry</var></h3>
6110</div>
6111
6112<p class="magick-description">Minify / magnify the image with pixel subsampling and pixel replication, respectively.</p>
6113
6114<p>Change the image size simply by directly sampling the pixels original
6115from the image.  When magnifying, pixels are replicated in blocks.  When
6116minifying, pixels are sub-sampled (i.e., some rows and columns are skipped
6117over). </p>
6118
6119<p>The results are thus equivalent to using <a href="command-line-options.html#resize">-resize</a> with
6120a <a href="command-line-options.html#filter">-filter</a> setting of <code>point</code> (nearest
6121neighbor), though <a href="command-line-options.html#sample">-sample</a> is a lot faster, as it
6122avoids all the filter processing of the image. As such it completely ignores
6123the current <a href="command-line-options.html#filter">-filter</a> setting. </p>
6124
6125<p>The key feature of the <a href="command-line-options.html#sample">-sample</a> is that no new colors
6126will be added to the resulting image, though some colors may disappear. </p>
6127
6128<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. Offsets, if present in the geometry string, are
6129ignored, unlike <a href="command-line-options.html#resize">-resize</a>. </p>
6130
6131
6132<p>The actual sampling point is the middle of the sub-region being sampled.
6133As such a single pixel sampling of an image will take the middle pixel, (or
6134top-left-middle if image has even dimensions).  However the <a
6135href="command-line-options.html#define">-define</a> '<code>sample:offset</code>' can be set to modify
6136this position some other location within each sub-region being sampled, as
6137a percentage offset.</p>
6138
6139<p>By default this value is '<code>50</code>' for the midpoint, but could be set
6140to '<code>0</code>' for top-left, '<code>100</code>' for bottom-right, or with
6141separate X and Y offsets such as '<code>0x50</code>' for left-middle edge of
6142sampling sub-region.</p>
6143
6144
6145<div style="margin: auto;">
6146  <h3><a class="anchor" id="sampling-factor"></a>-sampling-factor <var>horizontal-factor</var>x<var>vertical-factor</var></h3>
6147</div>
6148
6149<p class="magick-description">Sampling factors used by JPEG or MPEG-2 encoder and YUV decoder/encoder.</p>
6150
6151<p>This option specifies the sampling factors to be used by the JPEG encoder
6152for chroma downsampling. If this option is omitted, the JPEG library will use
6153its own default values. When reading or writing the YUV format and when
6154writing the M2V (MPEG-2) format, use <a
6155href="command-line-options.html#sampling-factor">-sampling-factor 2x1</a> or <a
6156href="command-line-options.html#sampling-factor">-sampling-factor 4:2:2</a> to specify the 4:2:2
6157downsampling method.</p>
6158
6159<div style="margin: auto;">
6160  <h3><a class="anchor" id="scale"></a>-scale <var>geometry</var></h3>
6161</div>
6162
6163<p class="magick-description">Minify / magnify the image with pixel block averaging and pixel replication, respectively.</p>
6164
6165<p>Change the image size simply by replacing pixels by averaging pixels
6166together when minifying, or replacing pixels when magnifying.  </p>
6167
6168<p>The results are thus equivalent to using <a href="command-line-options.html#resize">-resize</a> with
6169a <a href="command-line-options.html#filter">-filter</a> setting of <code>box</code>.  Though it is a lot
6170faster, as it avoids all the filter processing of the image. As such it
6171completely ignores the current <a href="command-line-options.html#filter">-filter</a> setting. </p>
6172
6173<p>If when shrinking (minifying) images the original image is some integer
6174multiple of the new image size, the number of pixels averaged together to
6175produce the new pixel color is the same across the whole image. This is
6176a special case known as 'binning' and is often used as a method of reducing
6177noise in image such as those generated by digital cameras, especially in low
6178light conditions. </p>
6179
6180
6181<div style="margin: auto;">
6182  <h3><a class="anchor" id="scene"></a>-scene <var>value</var></h3>
6183</div>
6184
6185<p class="magick-description">Set scene number.</p>
6186
6187<p>This option sets the scene number of an image or the first image in an image sequence.</p>
6188
6189<div style="margin: auto;">
6190  <h3><a class="anchor" id="screen"></a>-screen</h3>
6191</div>
6192
6193<p class="magick-description">Specify the screen to capture.</p>
6194
6195<p>This option indicates that the GetImage request used to obtain the image
6196should be done on the root window, rather than directly on the specified
6197window. In this way, you can obtain pieces of other windows that overlap the
6198specified window, and more importantly, you can capture menus or other popups
6199that are independent windows but appear over the specified window.</p>
6200
6201<div style="margin: auto;">
6202  <h3><a class="anchor" id="seed"></a>-seed</h3>
6203</div>
6204
6205<p class="magick-description">Seed a new sequence of pseudo-random numbers</p>
6206
6207<div style="margin: auto;">
6208  <h3><a class="anchor" id="segment"></a>-segment <var>cluster-threshold</var>x<var>smoothing-threshold</var></h3>
6209</div>
6210
6211<p class="magick-description">Segment the colors of an image.</p>
6212
6213<p>Segment an image by analyzing the histograms of the color components and
6214identifying units that are homogeneous with the fuzzy c-means technique. This
6215is part of the ImageMagick color quantization routines. </p>
6216
6217<p>Specify <var>cluster threshold</var> as the number of pixels in
6218each cluster that must exceed the cluster threshold to be considered valid.
6219<var>Smoothing threshold</var> eliminates noise in the second
6220derivative of the histogram. As the value is increased, you can expect
6221a smoother second derivative.  The default is 1.5.</p>
6222
6223<p>If the <a href="command-line-options.html#verbose">-verbose</a> setting is defined, a detailed report
6224of the color clusters is returned.</p>
6225
6226
6227<div style="margin: auto;">
6228  <h3><a class="anchor" id="selective-blur"></a>-selective-blur <var>radius</var><br />-selective-blur <var>radius</var>{x<var>sigma</var>}{<var>+threshold</var>}</h3>
6229</div>
6230
6231<p class="magick-description">Selectively blur pixels within a contrast threshold.</p>
6232
6233<p>Blurs those pixels that are less than or equal to the threshold in
6234contrast. The threshold may be expressed as a fraction of <var>QuantumRange</var> or as a percentage.</p>
6235
6236<div style="margin: auto;">
6237  <h3><a class="anchor" id="separate"></a>-separate</h3>
6238</div>
6239
6240<p class="magick-description">Separate an image channel into a grayscale image.  Specify the channel with <a href="command-line-options.html#channel">-channel</a>.</p>
6241
6242<div style="margin: auto;">
6243  <h3><a class="anchor" id="sepia-tone"></a>-sepia-tone <var>percent-threshold</var></h3>
6244</div>
6245
6246<p class="magick-description">Simulate a sepia-toned photo.</p>
6247
6248<p>Specify <var>threshold</var> as the percent threshold of the intensity (0 - 99.9%).</p>
6249
6250<p>This option applies a special effect to the image, similar to the effect
6251achieved in a photo darkroom by sepia toning.  Threshold ranges from 0 to <var>QuantumRange</var> and is a measure of the extent of the sepia
6252toning.  A threshold of 80% is a good starting point for a reasonable
6253tone.</p>
6254
6255
6256
6257<div style="margin: auto;">
6258  <h3><a class="anchor" id="set"></a>-set <var>key value</var></h3>
6259  <h3>+set <var>key</var></h3>
6260</div>
6261
6262<p class="magick-description">Sets image attributes and properties for images in the current image sequence.</p>
6263
6264<p>This will assign (or modify) specific settings attached to all the images
6265in the current image sequence.  Using the <a href="command-line-options.html#set">+set</a> form of the
6266option will either remove, or reset that setting to a default state, as
6267appropriate.  </p>
6268
6269<p>For example, it will modify specific well known image meta-data
6270'attributes' such as those normally overridden by: the options <a
6271href="command-line-options.html#delay" >-delay</a>, <a href="command-line-options.html#dispose" >-dispose</a>, and <a
6272href="command-line-options.html#page" >-page</a>, <a href="command-line-options.html#colorspace" >-colorspace</a>; generally
6273assigned before the image is read in, by using a <var>key</var> of
6274the same name. </p>
6275
6276<p>If the given <var>key</var> does not match a specific known
6277'attribute ', such as shown above, the setting is stored as a free form
6278'property' string.  Such settings are listed in <a href="command-line-options.html#verbose"
6279>-verbose</a> information ("<code>info:</code>" output format) as "Properties".
6280</p>
6281
6282<p>This includes string 'properties' that are set by and assigned to images
6283using the options <a href="command-line-options.html#comment" >-comment</a>, <a href="command-line-options.html#label"
6284>-label</a>, <a href="command-line-options.html#caption" >-caption</a>. These options actually assign
6285a global 'artifact' which are automatically assigned (and any <a href="../www/escape.html" >Format Percent
6286Escapes</a> expanded) to images as they are read in.  For example:</p>
6287
6288<pre class="highlight"><code>-> convert rose: -set comment 'Rose is a rose is a rose is a rose' rose.jpg
6289identify -format %c rose.jpg
6290Rose is a rose is a rose is a rose
6291</code></pre>
6292
6293<p>The set value can also make use of <a href="../www/escape.html" >Format and Print Image
6294Properties</a> in the defined value.  For example:</p>
6295
6296<pre class="highlight"><code>-> convert rose: -set origsize '%wx%h' -resize 50% \
6297  -format 'Old size = %[origsize]  New size = %wx%h' info:
6298Old size = 70x46  New size = 35x23
6299</code></pre>
6300
6301<p>Other well known 'properties' that are available include:
6302'<code>date:create</code>' and '<code>date:modify</code>' and
6303'<code>signature</code>'. </p>
6304
6305<p>The <a href="command-line-options.html#repage">-repage</a> operator will also allow you to modify
6306the '<code>page</code>' attribute of an image for images already in memory (also
6307see <a href="command-line-options.html#repage">-page</a>).  However it is designed to provide a finer
6308control of the sub-parts of this 'attribute'. The <a href="command-line-options.html#set">-set page</a>
6309option will only provide a direct, unmodified assignment of  '<code>page</code>'
6310attribute. </p>
6311
6312<p>This option can also associate a colorspace or profile with your image.
6313For example,</p>
6314
6315<pre class="highlight"><code>magick image.psd -set profile ISOcoated_v2_eci.icc image-icc.psd
6316</code></pre>
6317
6318<p>Some 'properties' must be defined in a specific way to be used. For
6319example only 'properties' prefixed with "<code>filename:</code>" can be used to
6320modify the output filename of an image. For example</p>
6321
6322<pre class="highlight"><code>magick rose: -set filename:mysize '%wx%h' 'rose_%[filename:mysize].png'
6323</code></pre>
6324
6325<p>If the setting value is prefixed with "<code>option:</code>" the setting will
6326be saved as a global "Artifact" exactly as if it was set using the <a
6327href="command-line-options.html#define" >-define</a> option. As such settings are global in scope, they
6328can be used to pass 'attributes' and 'properties' of one specific image,
6329in a way that allows you to use them in a completely different image, even if
6330the original image has long since been modified or destroyed. For example: </p>
6331
6332<pre class="highlight"><code>magick rose:  -set option:rosesize '%wx%h' -delete 0 \
6333  label:'%[rosesize]'   label_size_of_rose.gif"
6334</code></pre>
6335
6336<p>Note that <a href="../www/escape.html" >Format Percent Escapes</a> will only match
6337a 'artifact' if the given <var>key</var> does not match an existing
6338'attribute' or 'property'.  </p>
6339
6340<p>You can set the attributes of the image registry by prefixing the value
6341with <code>registry:</code>.</p>
6342
6343<p>The <a href="command-line-options.html#set">-set profile</a> option can also be used to inject
6344previously-formatted ancillary chunks into the output PNG file, using
6345the commandline option as shown below or by setting the profile via a
6346programming interface:</p>
6347
6348<pre class="highlight"><code>magick in.png -set profile PNG-chunk-x:&lt;filename&gt; out.png
6349</code></pre>
6350
6351<p>where <var>x</var> is a location flag and
6352<var>filename</var> is a file containing the chunk
6353name in the first 4 bytes, then a colon (":"), followed by the chunk data.
6354This encoder will compute the chunk length and CRC, so those must not
6355be included in the file.</p>
6356
6357<p>"x" can be "b" (before PLTE), "m" (middle, i.e., between PLTE and IDAT),
6358or "e" (end, i.e., after IDAT).  If you want to write multiple chunks
6359of the same type, then add a short unique string after the "x" to prevent
6360subsequent profiles from overwriting the preceding ones, e.g.,</p>
6361
6362
6363<pre class="highlight"><code>magick in.png -set profile PNG-chunk-b01:file01 \
6364  -profile PNG-chunk-b02:file02 out.png
6365</code></pre>
6366
6367<div style="margin: auto;">
6368  <h3><a class="anchor" id="shade"></a>-shade <var>azimuth</var>x<var>elevation</var></h3>
6369</div>
6370
6371<p class="magick-description">Shade the image using a distant light source.</p>
6372
6373<p>Specify <var>azimuth</var> and <var>elevation</var> as
6374the position of the light source. Use <a href="command-line-options.html#shade">+shade</a> to return
6375the shading results as a grayscale image.</p>
6376
6377<div style="margin: auto;">
6378  <h3><a class="anchor" id="shadow"></a>-shadow <var>percent-opacity</var>{x<var>sigma</var>}{<var>+-</var>}<var>x</var>{<var>+-</var>}<var>y</var>{<var>%</var>}</h3>
6379</div>
6380
6381<p class="magick-description">Simulate an image shadow.</p>
6382
6383<div style="margin: auto;">
6384  <h3><a
6385id="shared-memory"></a>-shared-memory</h3>
6386</div>
6387
6388<p class="magick-description">Use shared memory.</p>
6389
6390<p>This option specifies whether the utility should attempt to use shared
6391memory for pixmaps. ImageMagick must be compiled with shared memory support,
6392and the display must support the <var>MIT-SHM</var> extension.
6393Otherwise, this option is ignored. The default is <code>True</code>.</p>
6394
6395<div style="margin: auto;">
6396  <h3><a class="anchor" id="sharpen"></a>-sharpen <var>radius</var><br />-sharpen <var>radius</var>{x<var>sigma</var>}</h3>
6397</div>
6398
6399<p class="magick-description">Sharpen the image.</p>
6400
6401<p>Use a Gaussian operator of the given radius and standard deviation (sigma).</p>
6402
6403<div style="margin: auto;">
6404  <h3><a class="anchor" id="shave"></a>-shave <var>geometry</var></h3>
6405</div>
6406
6407<p class="magick-description">Shave pixels from the image edges.</p>
6408
6409<p>The <var>size</var> portion of the <var>geometry</var>
6410argument specifies the width of the region to be removed from both sides of
6411the image and the height of the regions to be removed from top and bottom.
6412Offsets are ignored.</p>
6413
6414<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
6415
6416<div style="margin: auto;">
6417  <h3><a class="anchor" id="shear"></a>-shear <var>Xdegrees</var>[x<var>Ydegrees</var>]</h3>
6418</div>
6419
6420<p class="magick-description">Shear the image along the x-axis and/or y-axis.</p>
6421
6422<p>The shear angles may be positive, negative, or zero. When <var>Ydegrees</var> is omitted it defaults to <var>Xdegrees</var>. When both angles are
6423given, the horizontal component of the shear is performed before the vertical
6424component.</p>
6425
6426<p>Shearing slides one edge of an image along the x-axis or y-axis (i.e.,
6427horizontally or vertically, respectively),creating a parallelogram. The amount
6428of each is controlled by the respective shear angle. For horizontal shears,
6429<var>Xdegrees</var> is measured clockwise relative to "up" (the
6430negative y-axis), sliding the top edge to the right when 0°&lt;<var>Xdegrees</var>&lt;90° and to the left when 90°&lt;<var>Xdegrees</var>&lt;180°.  For vertical shears <var>Ydegrees</var> is measured clockwise relative to "right" (the
6431positive x-axis), sliding the right edge down when 0°&lt;<var>Ydegrees</var>&lt;90° and up when 90°&lt;<var>Ydegrees</var>&lt;180°.</p>
6432
6433<p>Empty triangles left over from shearing the image are filled with the color
6434defined by the <a href="command-line-options.html#fill">-background</a> option. The color is specified
6435using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
6436
6437<p>The horizontal shear is performed before the vertical part. This is
6438important to note, since horizontal and vertical shears do not
6439<var>commute</var>, i.e., the order matters in a sequence of shears. For
6440example, the following two commands are not equivalent.</p>
6441
6442<pre class="highlight"><code>magick logo: -shear 20x0 -shear 0x60 logo-sheared.png
6443convert logo: -shear 0x60 -shear 20x0 logo-sheared.png
6444</code></pre>
6445
6446<p>The first of the two commands above is equivalent to the following, except
6447for the amount of empty space created; the command that follows generates
6448a smaller image, and so is a better choice in terms of time and space.</p>
6449
6450<pre class="highlight"><code>magick logo: -shear 20x60 logo-sheared.png
6451</code></pre>
6452
6453<div style="margin: auto;">
6454  <h3><a class="anchor" id="sigmoidal-contrast"></a>-sigmoidal-contrast <var>contrast</var>x<var>mid-point</var></h3>
6455</div>
6456
6457<p class="magick-description">Increase the contrast without saturating highlights or shadows.</p>
6458
6459<p>Increase the contrast of the image using a sigmoidal transfer function
6460without saturating highlights or shadows. <var>Contrast</var>
6461indicates how much to increase the contrast. For example, 0 is none, 3 is
6462typical and 20 is a lot.
6463</p>
6464
6465<p>The <var>mid-point</var> indicates where the maximum change
6466'slope' in contrast should fall in the resultant image (0 is white; 50% is
6467middle-gray; 100% is black). </p>
6468
6469<p>By default the image contrast is increased, use <var>+sigmoidal-contrast</var> to decrease the contrast.</p>
6470
6471<p>To achieve the equivalent of a sigmoidal brightness change (similar to
6472a gamma adjustment), you would use <var>-sigmoidal-contrast
6473{brightness}x0%</var> to increase brightness and <var>+sigmoidal-contrast {brightness}x0%</var> to decrease brightness.
6474Note the use of '0' fo rthe mid-point of the sigmoidal curve. </p>
6475
6476<p>Using a very high <var>contrast</var> will produce a sort of
6477'smoothed thresholding' of the image.  Not as sharp (with high aliasing
6478effects) of a true threshold, but with tapered gray-levels around the threshold
6479<var>mid-point</var>. </p>
6480
6481<div style="margin: auto;">
6482  <h3><a class="anchor" id="silent"></a>-silent</h3>
6483
6484
6485</div>
6486
6487<p class="magick-description">Operate silently. This option is only used
6488by the <a href="import.html">import</a> tool.</p>
6489
6490<div style="margin: auto;">
6491  <h3><a class="anchor" id="similarity-threshold"></a>-similarity-threshold <var>value</var></h3>
6492</div>
6493
6494<p class="magick-description">Minimum RMSE for subimage match.</p>
6495
6496<p>If this setting is used, then the search will stop as soon as it finds a match whose metric is less than or equal to the value. A partially filled second output image will result. Using a value of zero, will cause the search to stop at the first perfect match it finds. If this setting is left off, then the search will proceed to completion or as limited by <var>-dissimilarity-threshold</var>.</p>
6497
6498<div style="margin: auto;">
6499  <h3><a class="anchor" id="size"></a>-size <var>width</var>[x<var>height</var>][<var>+offset</var>]</h3>
6500</div>
6501
6502<p class="magick-description">Set the width and height of the image.</p>
6503
6504<p>Use this option to specify the width and height of raw images whose
6505dimensions are unknown such as <code>GRAY</code>, <code>RGB</code>, or
6506<code>CMYK</code>. In addition to width and height, use <a
6507href="command-line-options.html#size">-size</a> with an offset to skip any header information in the
6508image or tell the number of colors in a <code>MAP</code> image file, (e.g. -size
6509640x512+256).</p>
6510
6511<p>For Photo CD images, choose from these sizes:</p>
6512
6513<pre class="highlight"><code>192x128
6514384x256
6515768x512
65161536x1024
65173072x2048
6518</code></pre>
6519
6520<div style="margin: auto;">
6521  <h3><a class="anchor" id="sketch"></a>-sketch <var>radius</var><br />-sketch <var>radius</var>{x<var>sigma</var>}+<var>angle</var></h3>
6522</div>
6523
6524<p class="magick-description">Simulate a pencil sketch.</p>
6525
6526<p>Sketch with the given radius, standard deviation (sigma), and angle.   The
6527angle given is the angle toward which the image is sketched.  That is the
6528direction people would consider the object is coming from.  </p>
6529
6530<div style="margin: auto;">
6531  <h3><a class="anchor" id="smush"></a>-smush <var>offset</var></h3>
6532</div>
6533
6534<p class="magick-description">Appends an image sequence together ignoring transparency.</p>
6535
6536<p>Smush is a more flexible version of <a href="command-line-options.html#append">-append</a>, joining the images in the sequence top-to-bottom (<a href="command-line-options.html#smush">-smush</a>) or left-to-right (<a href="command-line-options.html#smush">+smush</a>), with a gap between images according to the specified offset.</p>
6537
6538<p>If the offset is negative, images will overlap by that amount.</p>
6539
6540<p><a href="command-line-options.html#smush">-smush</a> respects <a href="command-line-options.html#gravity">-gravity</a>. Any empty space will be filled with the <a href="command-line-options.html#background">-background</a> color.</p>
6541
6542<p>For zero offset and transparent images, the non-transparent parts of the two images will be aligned as close as possible without overlapping.</p>
6543
6544<div style="margin: auto;">
6545  <h3><a class="anchor" id="snaps"></a>-snaps <var>value</var></h3>
6546</div>
6547
6548<p class="magick-description">Set the number of screen snapshots.</p>
6549
6550<p>Use this option to grab more than one image from the X server screen, to create an animation sequence.</p>
6551
6552<div style="margin: auto;">
6553  <h3><a class="anchor" id="solarize"></a>-solarize <var>percent-threshold</var></h3>
6554</div>
6555
6556<p class="magick-description">Negate all pixels above the threshold level.</p>
6557
6558<p>Specify <var>factor</var> as the percent threshold of the intensity (0 - 99.9%).</p>
6559
6560<p>This option produces a <var>solarization</var> effect seen when
6561exposing a photographic film to light during the development process.</p>
6562
6563<div style="margin: auto;">
6564  <h3><a class="anchor" id="sort-pixels"></a>-sort-pixels</h3>
6565</div>
6566
6567<p class="magick-description">sorts pixels within each scanline in ascending order of intensity.</p>
6568
6569<div style="margin: auto;">
6570  <h3><a class="anchor" id="sparse-color"></a>-sparse-color <var>method</var>  '<var>x</var>,<var>y</var> <var>color</var>  ...'</h3>
6571</div>
6572
6573<p class="magick-description"> color the given image using the specified points of color, and filling the other intervening colors using the given methods. </p>
6574
6575
6576<div class="pre-scrollable highlight">
6577<dl class="row">
6578    <dt class="col-md-4">barycentric</dt>
6579    <dd class="col-md-8">three point triangle of color given 3 points.
6580        Giving only 2 points will form a linear gradient between those points.
6581        The gradient generated extends beyond the triangle created by those
6582        3 points. </dd>
6583    <dt class="col-md-4">bilinear</dt>
6584    <dd class="col-md-8">Like barycentric but for 4 points. Less than 4 points
6585        fall back to barycentric. </dd>
6586    <dt class="col-md-4">voronoi</dt>
6587    <dd class="col-md-8">Simply map each pixel to the to nearest color point
6588        given. The result are polygonal 'cells' of solid color. </dd>
6589    <dt class="col-md-4">manhattan</dt>
6590    <dd class="col-md-8">Like voronoi, but resulting polygonal 'cells' are mapped to a fixed coordinate system.</dd>
6591    <dt class="col-md-4">shepards</dt>
6592    <dd class="col-md-8">Colors points biased on the ratio of inverse distance
6593        squared. Generating spots of color in a sea of the average of
6594        colors. </dd>
6595    <dt class="col-md-4">inverse</dt>
6596    <dd class="col-md-8">Colors points biased on the ratio of inverse distance.
6597        This generates sharper points of color rather than rounded spots of
6598        '<code>shepards</code>'  Generating spots of color in a sea of the
6599        average of colors. </dd>
6600</dl>
6601</div>
6602
6603<p>The points are placed according to the images location on the virtual
6604canvas (<a href="command-line-options.html#page" >-page</a> or <a href="command-line-options.html#repage" >-repage</a>
6605offset), and do not actually have to exist on the given image, but may be
6606some point beyond the edge of the image. All points are floating point values.
6607</p>
6608
6609<p>Only the color channels defined by the <a href="command-line-options.html#channel" >-channel</a> are
6610modified, which means that by default matte/alpha transparency channel is not
6611affected. Typically transparency channel is turned off either before or after
6612the operation. </p>
6613
6614<p>Of course if some color points are transparent to generate a transparent
6615gradient, then the image also requires transparency enabled to store the
6616values. </p>
6617
6618<p>All the above methods when given a single point of color will replace all
6619the colors in the image with the color given, regardless of the point. This is
6620logical, and provides an alternative technique to recolor an image to some
6621default value. </p>
6622
6623
6624<div style="margin: auto;">
6625  <h3><a class="anchor" id="splice"></a>-splice <var>geometry</var></h3>
6626</div>
6627
6628<p class="magick-description">Splice the current background color into the image.</p>
6629
6630<p>This will add rows and columns of the current <a
6631href="command-line-options.html#background">-background</a> color into the given image according to the
6632given  <a href="command-line-options.html#gravity">-gravity</a> geometry setting.  See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. Essentially <a href="command-line-options.html#splice">-splice</a> will divide the
6633image into four quadrants, separating them by the inserted rows and columns.
6634</p>
6635
6636<p>If a dimension of geometry is zero no rows or columns will be added for that
6637dimension.  Similarly using a zero offset with the appropriate <a
6638href="command-line-options.html#gravity">-gravity</a> setting will add rows and columns to the edges of
6639the image, padding the image only along that one edge. Edge padding is what <a
6640href="command-line-options.html#splice">-splice</a> is most commonly used for. </p>
6641
6642<p>If the exact same  <var>geometry</var> and <a
6643href="command-line-options.html#gravity">-gravity</a> is later used with <a href="command-line-options.html#chop">-chop</a> the
6644added all splices removed. </p>
6645
6646<div style="margin: auto;">
6647  <h3><a class="anchor" id="spread"></a>-spread <var>amount</var></h3>
6648</div>
6649
6650<p class="magick-description">Displace image pixels by a random amount.</p>
6651
6652<p>The argument <var>amount</var> defines the size of the
6653neighborhood around each pixel from which to choose a candidate pixel to
6654blend.</p>
6655
6656<p>The lookup is controlled by the <a href="command-line-options.html#interpolate">-interpolate</a> setting.</p>
6657
6658<div style="margin: auto;">
6659  <h3><a class="anchor" id="statistic"></a>-statistic <var>type</var> <var>geometry</var></h3>
6660</div>
6661
6662<p class="magick-description">Replace each pixel with corresponding statistic from the neighborhood.</p>
6663
6664<p>Choose from these statistic types:</p>
6665
6666<div class="pre-scrollable highlight">
6667<dl class="row">
6668<dt class="col-md-4">Gradient</dt><dd class="col-md-8">maximum difference (max - min) value in neighborhood</dd>
6669<dt class="col-md-4">Maximum</dt><dd class="col-md-8">maximum value per channel in neighborhood</dd>
6670<dt class="col-md-4">Minimum</dt><dd class="col-md-8">minimum value per channel in neighborhood</dd>
6671<dt class="col-md-4">Mean</dt><dd class="col-md-8">average value per channel in neighborhood</dd>
6672<dt class="col-md-4">Median</dt><dd class="col-md-8">median value per channel in neighborhood</dd>
6673<dt class="col-md-4">Mode</dt><dd class="col-md-8">mode (most frequent) value per channel in neighborhood</dd>
6674<dt class="col-md-4">Nonpeak</dt><dd class="col-md-8">value just before or after the median value per channel in neighborhood</dd>
6675<dt class="col-md-4">RMS</dt><dd class="col-md-8">root mean square value per channel in neighborhood</dd>
6676<dt class="col-md-4">StandardDeviation</dt><dd class="col-md-8"> standard deviation value per channel in neighborhood</dd>
6677</dl>
6678</div>
6679
6680<div style="margin: auto;">
6681  <h3><a class="anchor" id="stegano"></a>-stegano <var>offset</var></h3>
6682</div>
6683
6684<p class="magick-description">Hide watermark within an image.</p>
6685
6686<p>Use an offset to start the image hiding some number of pixels from the
6687beginning of the image. Note this offset and the image size. You will need
6688this information to recover the steganographic image (e.g. display -size
6689320x256+35 stegano:image.png).</p>
6690
6691<div style="margin: auto;">
6692  <h3><a class="anchor" id="stereo"></a>-stereo <var>+x</var>{<var>+y</var>}</h3>
6693</div>
6694
6695<p class="magick-description">Composite two images to create a red / cyan stereo anaglyph.</p>
6696
6697<p>The left side of the stereo pair (second image) is saved as the red channel of the output image. The right side (first image) is saved as the green and blue channels. Red-green stereo glasses are required to properly view the stereo image.</p>
6698
6699<div style="margin: auto;">
6700  <h3><a class="anchor" id="storage-type"></a>-storage-type <var>type</var></h3>
6701</div>
6702
6703<p class="magick-description">Pixel storage type.  Here are the valid types:</p>
6704
6705<div class="pre-scrollable highlight">
6706<dl class="row">
6707<dt class="col-md-4">char</dt><dd class="col-md-8">unsigned characters</dd>
6708<dt class="col-md-4">double</dt><dd class="col-md-8">doubles</dd>
6709<dt class="col-md-4">float</dt><dd class="col-md-8">floats</dd>
6710<dt class="col-md-4">integer</dt><dd class="col-md-8">integers</dd>
6711<dt class="col-md-4">long</dt><dd class="col-md-8">longs</dd>
6712<dt class="col-md-4">quantum</dt><dd class="col-md-8">pixels in the native depth of your ImageMagick distribution</dd>
6713<dt class="col-md-4">short</dt><dd class="col-md-8">unsigned shorts</dd>
6714</dl>
6715</div>
6716
6717<p>Float and double types are normalized from 0.0 to 1.0 otherwise the pixels
6718values range from 0 to the maximum value the storage type can support.</p>
6719
6720<div style="margin: auto;">
6721  <h3><a class="anchor" id="stretch"></a>-stretch <var>fontStretch</var></h3>
6722</div>
6723
6724<p class="magick-description">Set a type of stretch style for fonts.</p>
6725
6726<p>This setting suggests a type of stretch that ImageMagick should try to
6727apply to the currently selected font family. Select <var>fontStretch</var> from the following.</p>
6728
6729<pre class="highlight"><code>Any
6730Condensed
6731Expanded
6732ExtraCondensed
6733ExtraExpanded
6734Normal
6735SemiCondensed
6736SemiExpanded
6737UltraCondensed
6738UltraExpanded
6739</code></pre>
6740
6741<p>To print a complete list of stretch types, use <a href="command-line-options.html#list">-list
6742stretch</a>.</p>
6743
6744<p>For other settings that affect fonts, see the options <a
6745href="command-line-options.html#font">-font</a>, <a href="command-line-options.html#family">-family</a>, <a
6746href="command-line-options.html#style">-style</a>, and <a href="command-line-options.html#weight">-weight</a>. </p>
6747
6748<div style="margin: auto;">
6749  <h3><a class="anchor" id="strip"></a>-strip</h3>
6750</div>
6751
6752<p class="magick-description">Strip the image of any profiles, comments or these PNG chunks: bKGD,cHRM,EXIF,gAMA,iCCP,iTXt,sRGB,tEXt,zCCP,zTXt,date.</p>
6753
6754<div style="margin: auto;">
6755  <h3><a class="anchor" id="stroke"></a>-stroke <var>color</var></h3>
6756</div>
6757
6758<p class="magick-description">Color to use when stroking a graphic primitive.</p>
6759
6760<p>The color is specified using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
6761
6762<p>See <a href="command-line-options.html#draw">-draw</a> for further details.</p>
6763
6764<div style="margin: auto;">
6765  <h3><a class="anchor" id="strokewidth"></a>-strokewidth <var>value</var></h3>
6766</div>
6767
6768<p class="magick-description">Set the stroke width.</p>
6769
6770<p>See <a href="command-line-options.html#draw">-draw</a> for further details.</p>
6771
6772<div style="margin: auto;">
6773  <h3><a class="anchor" id="style"></a>-style <var>fontStyle</var></h3>
6774</div>
6775
6776<p class="magick-description">Set a font style for text.</p>
6777
6778<p>This setting suggests a font style that ImageMagick should try to apply to
6779the currently selected font family. Select <var>fontStyle</var> from
6780the following.</p>
6781
6782<pre class="highlight"><code>Any
6783Italic
6784Normal
6785Oblique
6786</code></pre>
6787
6788<p>For other settings that affect fonts, see the options <a
6789href="command-line-options.html#font">-font</a>, <a href="command-line-options.html#family">-family</a>, <a
6790href="command-line-options.html#stretch">-stretch</a>, and <a href="command-line-options.html#weight">-weight</a>. </p>
6791
6792<div style="margin: auto;">
6793  <h3><a class="anchor" id="subimage-search"></a>-subimage-search</h3>
6794</div>
6795
6796<p class="magick-description">Search for subimage.</p>
6797
6798<p>This option is required to have compare search for the best match location
6799of a small image within a larger image. This search will produce two images
6800(or two frames). The first is the "difference" image and the second will
6801be the "match score" image.</p>
6802
6803<p>The "match-score" image is smaller containing a pixel for ever possible
6804position of the top-left corner of the given sub-image. that is its size will
6805be the size of the larger_image - sub_image + 1.  The brightest location in
6806this image is the location s the locate on the best match that is also
6807reported. Note that this may or may not be a perfect match, and the actual
6808brightness will reflect this. Other bright 'peaks' can be used to locate other
6809possible matching locations. </p>
6810
6811<p>Note that the search will try to compare the sub-image at every possible
6812location in the larger image, as such it can be very slow.  The smaller the
6813sub-image the faster this search is. </p>
6814
6815
6816<div style="margin: auto;">
6817  <h3><a class="anchor" id="swap"></a>-swap <var>index,index</var></h3>
6818</div>
6819
6820<p class="magick-description">Swap the positions of two images in the image sequence.</p>
6821
6822<p>For example, <a href="command-line-options.html#swap">-swap 0,2</a> swaps the first and the third
6823images in the current image sequence. Use <a href="command-line-options.html#swap">+swap</a> to switch
6824the last two images in the sequence.</p>
6825
6826<div style="margin: auto;">
6827  <h3><a class="anchor" id="swirl"></a>-swirl <var>degrees</var></h3>
6828</div>
6829
6830<p class="magick-description">Swirl image pixels about the center.</p>
6831
6832<p><var>Degrees</var> defines the tightness of the swirl.</p>
6833
6834<div style="margin: auto;">
6835  <h3><a class="anchor" id="synchronize"></a>-synchronize</h3>
6836</div>
6837
6838<p class="magick-description">Synchronize image to storage device.</p>
6839
6840<p>Set to "true" to ensure all image data is fully flushed and synchronized
6841to disk. There is a performance penalty, but the benefits include ensuring a
6842valid image file in the event of a system crash and early reporting if there
6843is not enough disk space for the image pixel cache.</p>
6844
6845<div style="margin: auto;">
6846  <h3><a class="anchor" id="taint"></a>-taint</h3>
6847</div>
6848
6849<p class="magick-description">Mark the image as modified.</p>
6850
6851<div style="margin: auto;">
6852  <h3><a class="anchor" id="text-font"></a>-text-font <var>name</var></h3>
6853</div>
6854
6855<p class="magick-description">Font for writing fixed-width text.</p>
6856
6857<p>Specifies the name of the preferred font to use in fixed (typewriter style)
6858formatted text. The default is 14 point <var>Courier</var>.</p>
6859
6860<p>You can tag a font to specify whether it is a PostScript, TrueType, or
6861OPTION1 font. For example, <code>Courier.ttf</code> is a TrueType font and
6862<code>x:fixed</code> is OPTION1.</p>
6863
6864<div style="margin: auto;">
6865  <h3><a class="anchor" id="texture"></a>-texture <var>filename</var></h3>
6866</div>
6867
6868<p class="magick-description">Name of texture to tile onto the image background.</p>
6869
6870<div style="margin: auto;">
6871  <h3><a class="anchor" id="threshold"></a>-threshold <var>value</var>{<var>%</var>}</h3>
6872</div>
6873
6874<!-- {<var>green,blue,opacity</var>}
6875<p>If the green or blue value is omitted, these channels use the same value as
6876the first one provided. If all three color values are the same, the result is
6877a bi-level image. If the opacity threshold is omitted, OpaqueOpacity is used
6878and any partially transparent pixel becomes fully transparent.</p>
6879-->
6880
6881<p class="magick-description">Apply simultaneous black/white threshold to the image.</p>
6882
6883<p>Any pixel values (more specifically, those channels set using <a class="text-nowrap" href="command-line-options.html#channel">-channel</a>) that exceed the specified threshold are reassigned the
6884maximum channel value, while all other values are assigned the minimum.</p>
6885
6886<p> The threshold value can be given as a percentage or as an absolute integer
6887value corresponding to the desired channel value. When given as an integer,
6888the minimum attainable value is 0 (corresponding to black when all channels
6889are affected), but the maximum value (corresponding to white) is that of the
6890<code>quantum depth</code> of the particular build of ImageMagick, and is
6891therefore dependent on the installation. For that reason, a reasonable
6892recommendation for most applications is to specify the threshold values as
6893a percentage.  </p>
6894
6895<p> The following would force pixels with red values above 50% to have 100%
6896red values, while those at or below 50% red would be set to 0 in the red
6897channel. The green, blue, and alpha channels (if present) would be unchanged.
6898</p>
6899
6900<pre class="highlight"><code>magick in.png -channel red -threshold 50% out.png
6901</code></pre>
6902
6903<p>As (possibly) impractical but instructive examples, the following would
6904generate an all-black and an all-white image with the same dimensions as the
6905input image.</p>
6906
6907
6908<pre class="highlight"><code>magick in.png -channel RGB -threshold 100% black.png
6909convert in.png -channel RGB -threshold -1 white.png
6910</code></pre>
6911
6912<p> See also <a class="text-nowrap" href="command-line-options.html#black-threshold">-black-threshold</a> and <a class="text-nowrap" href="command-line-options.html#white-threshold">-white-threshold</a>.
6913</p>
6914
6915<div style="margin: auto;">
6916  <h3><a class="anchor" id="thumbnail"></a>-thumbnail <var>geometry</var></h3>
6917</div>
6918
6919<p class="magick-description">Create a thumbnail of the image.</p>
6920
6921<p>This is similar to <a href="command-line-options.html#resize">-resize</a>, except it is optimized
6922for speed and any image profile, other than a color profile, is removed to
6923reduce the thumbnail size.  To strip the color profiles as well, add <a
6924href="command-line-options.html#strip">-strip</a> just before of after this option.</p>
6925
6926<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
6927
6928<div style="margin: auto;">
6929  <h3><a class="anchor" id="tile"></a>-tile <var>filename</var></h3>
6930</div>
6931
6932<p class="magick-description">Set the tile image used for filling a subsequent graphic primitive.</p>
6933
6934<div style="margin: auto;">
6935  <h3>-tile <var>geometry</var></h3>
6936</div>
6937
6938<p class="magick-description">Specify the layout of images.</p>
6939
6940<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
6941
6942<div style="margin: auto;">
6943  <h3>-tile</h3>
6944</div>
6945
6946<p class="magick-description">Specifies that a subsequent composite operation is repeated across and down image.</p>
6947
6948<div style="margin: auto;">
6949  <h3><a class="anchor" id="tile-offset"></a>-tile-offset {<var>+-</var>}<var>x</var>{<var>+-</var>}<var>y</var></h3>
6950</div>
6951
6952<p class="magick-description">Specify the offset for tile images, relative to the background image it is tiled on.</p>
6953
6954<p>This should be set before the tiling image is set by <a href="command-line-options.html#tile"
6955>-tile</a> or <a href="command-line-options.html#texture" >-texture</a>, or directly applied for
6956creating a tiled canvas using <code>TILE:</code> or <code>PATTERN:</code> input
6957formats. </p>
6958
6959<p>Internally ImageMagick does a <a href="command-line-options.html#roll" >-roll</a> of the tile image
6960by the arguments given when the tile image is set. </p>
6961
6962<div style="margin: auto;">
6963  <h3><a class="anchor" id="tint"></a>-tint <var>value</var></h3>
6964</div>
6965
6966<p class="magick-description">Tint the image with the fill color.</p>
6967
6968<p>Tint the image with the fill color.</p>
6969
6970<p>Specify the amount of tinting as a percentage.  Pure colors like black,
6971white red, yellow, will not be affected by -tint. Only mid-range colors such
6972as the various shades of grey.</p>
6973
6974<div style="margin: auto;">
6975  <h3><a class="anchor" id="title"></a>-title <var>string</var></h3>
6976</div>
6977
6978<p class="magick-description">Assign a title to displayed image.", "animate", "display", "montage</p>
6979
6980<p>Use this option to assign a specific title to the image. This assigned to
6981the image window and is typically displayed in the window title bar.
6982Optionally you can include the image filename, type, width, height, Exif data,
6983or other image attribute by embedding special format characters described
6984under the <a href="command-line-options.html#format">-format</a> option.</p>
6985
6986<p>For example,</p>
6987
6988<pre class="highlight"><code>-title "%m:%f %wx%h"
6989</code></pre>
6990
6991<p>produces an image title of <code>MIFF:bird.miff 512x480</code> for an image
6992titled <code>bird.miff</code> and whose width is 512 and height is 480.</p>
6993
6994
6995<div style="margin: auto;">
6996  <h3><a class="anchor" id="transform"></a>-transform</h3>
6997</div>
6998
6999<p class="magick-description">Transform the image.</p>
7000
7001<p>This option applies the transformation matrix from a previous <a href="command-line-options.html#affine">-affine</a> option.</p>
7002
7003<pre class="highlight"><code>magick -affine 2,2,-2,2,0,0 -transform bird.ppm bird.jpg
7004</code></pre>
7005
7006
7007<p>This operator has been now been superseded by the  <a
7008href="command-line-options.html#distort">-distort</a> '<code>AffineProjection</code>' method. </p>
7009
7010
7011<div style="margin: auto;">
7012  <h3><a class="anchor" id="transparent"></a>-transparent <var>color</var></h3>
7013</div>
7014
7015<p class="magick-description">Make this color transparent within the image.</p>
7016
7017<p>The <var>color</var> argument is defined using the format
7018described under the <a href="command-line-options.html#fill">-fill</a> option. The <a href="command-line-options.html#fuzz"
7019>-fuzz</a> setting can be used to match and replace colors similar to the one
7020given. </p>
7021
7022<p>Use  <a href="command-line-options.html#transparent" >+transparent</a> to invert the pixels matched.
7023that is make all non-matching colors transparent. </p>
7024
7025<p>The <a href="command-line-options.html#opaque">-opaque</a>  operator is exactly the same as <a
7026href="command-line-options.html#transparent" >-transparent</a> but replaces the matching color with the
7027current <a href="command-line-options.html#fill">-fill</a> color setting, rather than transparent.
7028However the <a href="command-line-options.html#transparent" >-transparent</a> operator also ensures
7029that the image has an alpha channel enabled, as per "<code><a href="command-line-options.html#alpha"
7030>-alpha</a> set</code>", and does not require you to modify the <a
7031href="command-line-options.html#channel">-channel</a> to enable alpha channel handling. </p>
7032
7033<p>Note that this does not define the color as being the 'transparency color'
7034used for color-mapped image formats, such as GIF.  For that use <a
7035href="command-line-options.html#transparent-color" >-transparent-color</a> </p>
7036
7037
7038<div style="margin: auto;">
7039  <h3><a class="anchor" id="transparent-color"></a>-transparent-color <var>color</var></h3>
7040</div>
7041
7042<p class="magick-description">Set the transparent color.</p>
7043
7044<p>Sometimes this is used for saving to image formats such as
7045GIF and PNG8 which uses this color to represent boolean transparency.  This
7046does not make a color transparent, it only defines what color the transparent
7047color is in the color palette of the saved image. Use <a
7048href="command-line-options.html#transparent">-transparent</a> to make an opaque color transparent.</p>
7049
7050<p>This option allows you to have both an opaque visible color, as well as a
7051transparent color of the same color value without conflict.  That is, you can
7052use the same color for both the transparent and opaque color areas within an
7053image.  This, in turn, frees to you to select a transparent color that is
7054appropriate when an image is displayed by an application that does not handle a
7055transparent color index, while allowing ImageMagick to correctly handle images of this
7056type. </p>
7057
7058<p>The default transparent color is <code>#00000000</code>, which is fully transparent black.</p>
7059
7060<div style="margin: auto;">
7061  <h3><a class="anchor" id="transpose"></a>-transpose</h3>
7062</div>
7063
7064<p class="magick-description">Mirror the image along the top-left to bottom-right diagonal.</p>
7065
7066<p> This option mathematically transposes the pixel array.  It is equivalent to the sequence <code>-flip -rotate 90</code>.
7067</p>
7068
7069<div style="margin: auto;">
7070  <h3><a class="anchor" id="transverse"></a>-transverse</h3>
7071</div>
7072
7073<p class="magick-description">Mirror the image along the images bottom-left top-right diagonal.  Equivalent to the operations <code>-flop -rotate 90</code>.</p>
7074
7075
7076<div style="margin: auto;">
7077  <h3><a class="anchor" id="treedepth"></a>-treedepth <var>value</var></h3>
7078</div>
7079
7080<p class="magick-description">Tree depth for the color reduction algorithm.</p>
7081
7082<p>Normally, this integer value is zero or one. A value of zero or one causes
7083the use of an optimal tree depth for the color reduction algorithm.</p>
7084
7085<p>An optimal depth generally allows the best representation of the source
7086image with the fastest computational speed and the least amount of memory.
7087However, the default depth is inappropriate for some images. To assure the
7088best representation, try values between 2 and 8 for this parameter.  Refer to
7089the <a href="../www/quantize.html"
7090>color reduction algorithm</a> for more details.</p>
7091
7092<p>The <a href="command-line-options.html#colors">-colors</a> or <a href="command-line-options.html#monochrome">-monochrome</a>
7093option, or writing to an image format which requires color reduction, is
7094required for this option to take effect.</p>
7095
7096<div style="margin: auto;">
7097  <h3><a class="anchor" id="trim"></a>-trim</h3>
7098</div>
7099
7100<p class="magick-description">Trim an image.</p>
7101
7102<p>This option removes any edges that are exactly the same color as the corner
7103pixels. Use <a href="command-line-options.html#fuzz">-fuzz</a> to make <a href="command-line-options.html#trim">-trim</a> remove
7104edges that are nearly the same color as the corner pixels.</p>
7105
7106<p>The page or virtual canvas information of the image is preserved allowing
7107you to extract the result of the <a href="command-line-options.html#trim">-trim</a> operation from the
7108image.  Use a <a href="command-line-options.html#repage">+repage</a> to remove the virtual canvas page
7109information if it is unwanted.</p>
7110
7111<p>If the trimmed image 'disappears' an warning is produced, and a special
7112single pixel transparent 'missed' image is returned, in the same way as when a
7113<a href="command-line-options.html#crop">-crop</a> operation 'misses' the image proper. </p>
7114
7115<p>Use <code><a href="command-line-options.html#define">-define</a> trim:percent-background=0%</code> to
7116remove all the background from the image.  The amount of background that is
7117tolerated in an edge specified as a percent.  0% means no background is tolerated.
711850% means an edge can contain up to 50% pixels that are background per the fuzz-factor.</p>
7119
7120<p>Use <code><a href="command-line-options.html#define">-define</a> trim:edges={north,east,south,west}</code> separated by commas to only trim the specified edges of the image, e.g. <code>-define trim:edges=north,south</code>.</p>
7121
7122<p>Use <code><a href="command-line-options.html#background">-background</a> <em>background-color</em></code> to
7123identify background color surrounding the region of interest.</p>
7124
7125<div style="margin: auto;">
7126  <h3><a class="anchor" id="type"></a>-type <var>type</var></h3>
7127</div>
7128
7129<p class="magick-description">The image type.</p> <p>Choose from: <code>Bilevel</code>,
7130<code>Grayscale</code>, <code>GrayscaleAlpha</code>, <code>Palette</code>,
7131<code>PaletteAlpha</code>, <code>TrueColor</code>, <code>TrueColorAlpha</code>,
7132<code>ColorSeparation</code>, or <code>ColorSeparationAlpha</code>.</p>
7133
7134<p>Normally, when a format supports different subformats such as grayscale and
7135truecolor, the encoder will try to choose an efficient subformat. The <a
7136href="command-line-options.html#type">-type</a> option can be used to override this behavior. For
7137example, to prevent a JPEG from being written in grayscale format even though
7138only gray pixels are present, use.</p>
7139
7140<pre class="highlight"><code>magick bird.png -type TrueColor bird.jpg
7141</code></pre>
7142
7143<p>Similarly, use <a href="command-line-options.html#type">-type TrueColorAlpha</a> to force the
7144encoder to write an alpha channel even though the image is opaque, if the
7145output format supports transparency.</p>
7146
7147<p>Use <a href="command-line-options.html#type">-type optimize</a> to ensure the image is written in the smallest possible file size.</p>
7148
7149<div style="margin: auto;">
7150  <h3><a class="anchor" id="undercolor"></a>-undercolor <var>color</var></h3>
7151</div>
7152
7153<p class="magick-description">Set the color of the annotation bounding box.</p>
7154
7155<p>The color is specified using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
7156
7157<p>See <a href="command-line-options.html#draw">-draw</a> for further details.</p>
7158
7159
7160<div style="margin: auto;">
7161  <h3><a class="anchor" id="update"></a>-update <var>seconds</var></h3>
7162</div>
7163
7164<p class="magick-description">Detect when image file is modified and redisplay.</p>
7165
7166<p>Suppose that while you are displaying an image the file that is currently
7167displayed is over-written.  <code>display</code> will automagically detect that
7168the input file has been changed and update the displayed image
7169accordingly.</p>
7170
7171
7172<div style="margin: auto;">
7173  <h3><a class="anchor" id="unique-colors"></a>-unique-colors</h3>
7174</div>
7175
7176<p class="magick-description">Discard all but one of any pixel color.</p>
7177
7178
7179<div style="margin: auto;">
7180  <h3><a class="anchor" id="units"></a>-units <var>type</var></h3>
7181</div>
7182
7183<p class="magick-description">The units of image resolution.</p>
7184
7185<p>Choose from: <code>Undefined</code>, <code>PixelsPerInch</code>, or
7186<code>PixelsPerCentimeter</code>. This option is normally used in conjunction
7187with the <a href="command-line-options.html#density">-density</a> option.</p>
7188
7189
7190<div style="margin: auto;">
7191  <h3><a class="anchor" id="unsharp"></a>-unsharp <var>radius</var><br />-unsharp <var>radius</var>{x<var>sigma</var>}{<var>+gain</var>}{<var>+threshold</var>}</h3>
7192</div>
7193
7194<p class="magick-description">Sharpen the image with an unsharp mask operator.</p>
7195
7196<p>The <a href="command-line-options.html#unsharp">-unsharp</a> option sharpens an image. The image is
7197convolved with a Gaussian operator of the given radius and standard deviation
7198(sigma). For reasonable results, radius should be larger than sigma. Use
7199a radius of 0 to have the method select a suitable radius.</p>
7200
7201<p>The parameters are:</p>
7202
7203<div class="pre-scrollable highlight">
7204<dl class="row">
7205<dt class="col-md-4">radius</dt>
7206<dd class="col-md-8">The radius of the Gaussian, in pixels,  not counting the center pixel (default 0).</dd>
7207<dt class="col-md-4">sigma</dt>
7208<dd class="col-md-8">The standard deviation of the Gaussian, in pixels (default 1.0).</dd>
7209<dt class="col-md-4">gain</dt>
7210<dd class="col-md-8">The fraction of the difference between the original and the blur image that is added back into the original (default 1.0).</dd>
7211<dt class="col-md-4">threshold</dt>
7212<dd class="col-md-8">The threshold, as a fraction of <var>QuantumRange</var>, needed to apply the difference amount (default 0.05).</dd>
7213</dl>
7214</div>
7215
7216<div style="margin: auto;">
7217  <h3><a class="anchor" id="verbose"></a>-verbose</h3>
7218</div>
7219
7220<p class="magick-description">Print detailed information about the image when this option precedes the <a href="command-line-options.html#identify">-identify</a> option or <code>info:</code>.</p>
7221
7222
7223<div style="margin: auto;">
7224  <h3><a class="anchor" id="version"></a>-version</h3>
7225</div>
7226
7227<p class="magick-description">Print ImageMagick version string and exit.</p>
7228
7229
7230<div style="margin: auto;">
7231  <h3><a class="anchor" id="view"></a>-view <var>string</var></h3>
7232</div>
7233
7234<p class="magick-description">FlashPix viewing parameters.</p>
7235
7236
7237<div style="margin: auto;">
7238  <h3><a class="anchor" id="vignette"></a>-vignette <var>radius</var>{x<var>sigma</var>}{<var>+-</var>}<var>x</var>{<var>+-</var>}<var>y</var>{<var>%</var>}</h3>
7239</div>
7240
7241<p class="magick-description">Soften the edges of the image in vignette style.</p>
7242
7243<p>The vignette effect rolloff is controlled by radiusxsigma. For nominal rolloff, this would be set to 0xsigma. A value of 0x0 will produce a circle/ellipse with no rolloff. The arguments x and y control the size of the circle. Larger values decrease the radii and smaller values increase the radii. Values of +0+0 will generate a circle/ellipse the same size as the image. The default values for x and y are 10% of the corresponding image dimension. Thus, the radii will be decreased by 10%, i.e., the diameters of the circle/ellipse will be 80% of the corresponding image dimension.</p>
7244
7245<div style="margin: auto;">
7246  <h3><a class="anchor" id="virtual-pixel"></a>-virtual-pixel <var>method</var></h3>
7247</div>
7248
7249<p class="magick-description">Specify contents of <var>virtual pixels</var>.</p>
7250
7251<p>This option defines what color source should be used if and when a color
7252lookup completely 'misses' the source image. The color(s) that appear to
7253surround the source image.  Generally this color is derived from the source
7254image, but could also be set to a specify background color. </p>
7255
7256<p>Choose from these methods:</p>
7257
7258<div class="pre-scrollable highlight">
7259<dl class="row">
7260<dt class="col-md-4">background</dt><dd class="col-md-8">the area surrounding the image is the background color</dd>
7261<dt class="col-md-4">black</dt><dd class="col-md-8">the area surrounding the image is black</dd>
7262<dt class="col-md-4">checker-tile</dt><dd class="col-md-8">alternate squares with image and background color</dd>
7263<dt class="col-md-4">dither</dt><dd class="col-md-8">non-random 32x32 dithered pattern</dd>
7264<dt class="col-md-4">edge</dt><dd class="col-md-8">extend the edge pixel toward infinity</dd>
7265<dt class="col-md-4">gray</dt><dd class="col-md-8">the area surrounding the image is gray</dd>
7266<dt class="col-md-4">horizontal-tile</dt><dd class="col-md-8">horizontally tile the image, background color above/below</dd>
7267<dt class="col-md-4">horizontal-tile-edge</dt><dd class="col-md-8">horizontally tile the image and replicate the side edge pixels</dd>
7268<dt class="col-md-4">mirror</dt><dd class="col-md-8">mirror tile the image</dd>
7269<dt class="col-md-4">random</dt><dd class="col-md-8">choose a random pixel from the image</dd>
7270<dt class="col-md-4">tile</dt><dd class="col-md-8">tile the image (default)</dd>
7271<dt class="col-md-4">transparent</dt><dd class="col-md-8">the area surrounding the image is transparent blackness</dd>
7272<dt class="col-md-4">vertical-tile</dt><dd class="col-md-8">vertically tile the image, sides are background color</dd>
7273<dt class="col-md-4">vertical-tile-edge</dt><dd class="col-md-8">vertically tile the image and replicate the side edge pixels</dd>
7274<dt class="col-md-4">white</dt><dd class="col-md-8">the area surrounding the image is white</dd>
7275</dl>
7276</div>
7277
7278<p>The default value is "edge".</p>
7279
7280<p>This most important for distortion operators such as <a href="command-line-options.html#distort"
7281>-distort</a>, <a href="command-line-options.html#implode" >-implode</a>, and <a href="command-line-options.html#fx" >-fx</a>.
7282However it also affects operations that may access pixels just outside the
7283image proper, such as <a href="command-line-options.html#convolve">-convolve</a>, <a
7284href="command-line-options.html#blur">-blur</a>, and <a href="command-line-options.html#sharpen">-sharpen</a>. </p>
7285
7286<p>To print a complete list of virtual pixel types, use the <a
7287href="command-line-options.html#list">-list virtual-pixel</a> option.</p>
7288
7289
7290<div style="margin: auto;">
7291  <h3><a class="anchor" id="visual"></a>-visual <var>type</var></h3>
7292</div>
7293
7294<p class="magick-description">Animate images using this X visual type.", 'animate', 'display'</p>
7295
7296<p>Choose from these visual classes:</p>
7297
7298<pre class="highlight"><code>StaticGray    TrueColor
7299GrayScale     DirectColor
7300StaticColor   default
7301PseudoColor   visual id
7302</code></pre>
7303
7304<p>The X server must support the visual you choose, otherwise an error occurs.
7305If a visual is not specified, the visual class that can display the most
7306simultaneous colors on the default screen is chosen.</p>
7307
7308
7309<div style="margin: auto;">
7310  <h3><a class="anchor" id="watermark"></a>-watermark <var>brightness</var>x<var>saturation</var></h3>
7311</div>
7312
7313<p class="magick-description">Watermark an image using the given percentages of brightness and saturation.</p>
7314
7315<p>Take a grayscale image (with alpha mask) and modify the destination image's
7316brightness according to watermark image's grayscale value and the
7317<var>brightness</var> percentage.  The destinations color saturation
7318attribute is just direct modified by the <var>saturation</var>
7319percentage, which defaults to 100 percent (no color change). </p>
7320
7321
7322<div style="margin: auto;">
7323  <h3><a class="anchor" id="wave"></a>-wave <var>amplitude</var><br />-wave <var>amplitude</var>x<var>wavelength</var></h3>
7324</div>
7325
7326<p class="magick-description">Shear the columns of an image into a sine wave.</p>
7327
7328<div style="margin: auto;">
7329  <h3><a class="anchor" id="wavelet-denoise"></a>-wavelet-denoise <var>threshold</var><br />-wavelet-denoise <var>threshold</var>x<var>softness</var></h3>
7330</div>
7331
7332<p class="magick-description">Removes noise from the image using a wavelet transform.  The threshold is the value below which everything is considered noise and ranges from 0.0 (none) to QuantumRange or use percent (e.g. 5%). Softness attenuates the threshold and typically ranges from 0.0 (none) to 1.0.  The higher the value the more noise that remains in the image.</p>
7333
7334<div style="margin: auto;">
7335  <h3><a class="anchor" id="weight"></a>-weight <var>fontWeight</var></h3>
7336</div>
7337
7338<p class="magick-description">Set a font weight for text.</p>
7339
7340<p>This setting suggests a font weight that ImageMagick should try to apply to
7341the currently selected font family. Use a positive integer for
7342<var>fontWeight</var> or select from the following.</p>
7343
7344<div class="pre-scrollable highlight">
7345<dl class="row">
7346<dt class="col-md-4">Thin </dt>
7347<dd class="col-md-8">Same as <var>fontWeight</var> = 100.</dd>
7348<dt class="col-md-4">ExtraLight </dt>
7349<dd class="col-md-8">Same as <var>fontWeight</var> = 200.</dd>
7350<dt class="col-md-4">Light </dt>
7351<dd class="col-md-8">Same as <var>fontWeight</var> = 300.</dd>
7352<dt class="col-md-4">Normal </dt>
7353<dd class="col-md-8">Same as <var>fontWeight</var> = 400.</dd>
7354<dt class="col-md-4">Medium </dt>
7355<dd class="col-md-8">Same as <var>fontWeight</var> = 500.</dd>
7356<dt class="col-md-4">DemiBold </dt>
7357<dd class="col-md-8">Same as <var>fontWeight</var> = 600.</dd>
7358<dt class="col-md-4">Bold </dt>
7359<dd class="col-md-8">Same as <var>fontWeight</var> = 700.</dd>
7360<dt class="col-md-4">ExtraBold </dt>
7361<dd class="col-md-8">Same as <var>fontWeight</var> = 800.</dd>
7362<dt class="col-md-4">Heavy </dt>
7363<dd class="col-md-8">Same as <var>fontWeight</var> = 900.</dd>
7364</dl>
7365</div>
7366<br/>
7367
7368<p>To print a complete list of weight types, use <a href="command-line-options.html#list">-list weight</a>.</p>
7369
7370<p>For other settings that affect fonts, see the options <a
7371href="command-line-options.html#font">-font</a>, <a href="command-line-options.html#family">-family</a>, <a
7372href="command-line-options.html#stretch">-stretch</a>, and <a href="command-line-options.html#style">-style</a>. </p>
7373
7374<div style="margin: auto;">
7375  <h3><a class="anchor" id="white-balance"></a>-white-balance</h3>
7376</div>
7377<p>Applies white balancing to an image according to a grayworld assumption in the LAB colorspace.</p>
7378<p>Use <kbd>-define white-balance:vibrance=<em>value{%}</em></kdb> to change the color vibrance of the a &amp; b channels.</p>
7379
7380<div style="margin: auto;">
7381  <h3><a class="anchor" id="white-point"></a>-white-point <var>x,y</var></h3>
7382</div>
7383
7384<p class="magick-description">Chromaticity white point.</p>
7385
7386<div style="margin: auto;">
7387  <h3><a class="anchor" id="white-threshold"></a>-white-threshold <var>value</var>{<var>%</var>}</h3>
7388</div>
7389
7390<p class="magick-description">Force to white all pixels above the threshold while leaving all pixels at or below the threshold unchanged.</p>
7391
7392<p> The threshold value can be given as a percentage or as an absolute integer
7393value within [0, <var>QuantumRange</var>] corresponding to the
7394desired <a class="text-nowrap" href="command-line-options.html#channel">-channel</a> value. See <a class="text-nowrap" href="command-line-options.html#threshold">-threshold</a>for more details on thresholds and resulting values.  </p>
7395
7396<div style="margin: auto;">
7397  <h3><a class="anchor" id="window"></a>-window <var>id</var></h3>
7398</div>
7399
7400<p class="magick-description">Make the image the background of a window.", 'animate', 'display'</p>
7401
7402<p><var>id</var> can be a window id or name. Specify <code>root</code>
7403to select X's root window as the target window.</p>
7404
7405<p>By default the image is tiled onto the background of the target window. If
7406<code>backdrop</code> or <a href="command-line-options.html#geometry">-resize</a> are specified, the
7407image is surrounded by the background color. Refer to <code>X RESOURCES</code>
7408for details.</p>
7409
7410<p>The image will not display on the root window if the image has more unique
7411colors than the target window colormap allows. Use <a
7412href="command-line-options.html#colors">-colors</a> to reduce the number of colors.</p>
7413
7414<div style="margin: auto;">
7415  <h3><a class="anchor" id="window-group"></a>-window-group</h3>
7416</div>
7417
7418<p class="magick-description">Specify the window group.</p>
7419
7420<div style="margin: auto;">
7421  <h3><a class="anchor" id="write"></a>-write <var>filename</var></h3>
7422</div>
7423
7424<p class="magick-description">Write an image sequence.</p>
7425
7426<p>The image sequence preceding the <a href="command-line-options.html#write">-write</a> <var>filename</var> option is written out, and processing continues with the same image in its current state if there are additional options. To restore the image to its original state after writing it, use the <a href="command-line-options.html#write">+write</a> <var>filename</var> option.</p>
7427
7428<p>Use <a href="command-line-options.html#compress">-compress</a> to specify the type of image compression.</p>
7429
7430<div style="margin: auto;">
7431  <h3><a class="anchor" id="write-mask"></a>-write-mask <var>filename</var></h3>
7432</div>
7433
7434<p class="magick-description">Prevent updates to image pixels specified by the mask.</p>
7435
7436<p>This the same as using a mask used for composite masking operations, with
7437grayscale values causing blended updates of the image the mask is attached to.
7438</p>
7439
7440<p>Use <a href="command-line-options.html#write-mask">+write-mask</a> to remove the mask from images.</p>
7441
7442<p>Also see <a href="command-line-options.html#clip-mask">-clip-mask</a> which work in the same way,
7443but with strict boolean masking. </p>
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