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href="command-line-options.html#transparent">‑transparent</a> • <a href="command-line-options.html#transparent-color">‑transparent‑color</a> • <a href="command-line-options.html#transpose">‑transpose</a> • <a href="command-line-options.html#transverse">‑transverse</a> • <a href="command-line-options.html#treedepth">‑treedepth</a> • <a href="command-line-options.html#trim">‑trim</a> • <a href="command-line-options.html#type">‑type</a> • <a href="command-line-options.html#undercolor">‑undercolor</a> • <a href="command-line-options.html#unique-colors">‑unique‑colors</a> • <a href="command-line-options.html#units">‑units</a> • <a href="command-line-options.html#unsharp">‑unsharp</a> • <a href="command-line-options.html#update">‑update</a> • <a href="command-line-options.html#verbose">‑verbose</a> • <a href="command-line-options.html#version">‑version</a> • <a href="command-line-options.html#view">‑view</a> • <a href="command-line-options.html#vignette">‑vignette</a> • <a href="command-line-options.html#virtual-pixel">‑virtual‑pixel</a> • <a href="command-line-options.html#visual">‑visual</a> • <a href="command-line-options.html#watermark">‑watermark</a> • <a href="command-line-options.html#wave">‑wave</a> • <a href="command-line-options.html#wavelet-denoise">‑wavelet‑denoise</a> • <a href="command-line-options.html#weight">‑weight</a> • <a href="command-line-options.html#white-point">‑white‑point</a> • <a href="command-line-options.html#white-threshold">‑white‑threshold</a> • <a href="command-line-options.html#window">‑window</a> • <a href="command-line-options.html#window-group">‑window‑group</a> • <a href="command-line-options.html#write">‑write</a> </p> 60 61<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="convert.html">convert</a> and <a href="mogrify.html">mogrify</a>.</p> 62 63<div style="margin: auto;"> 64 <h3 class="magick-header"><a id="adaptive-blur"></a>-adaptive-blur <var>radius</var>[x<var>sigma</var>]</h3> 65</div> 66 67<p class="magick-description">Adaptively blur pixels, with decreasing effect near edges.</p> 68 69<p>A Gaussian operator of the given radius and standard deviation (<var>sigma</var>) is used. If <var>sigma</var> is not given it 70defaults to 1.</p> 71 72<div style="margin: auto;"> 73 <h3 class="magick-header"><a id="adaptive-resize"></a>-adaptive-resize <var>geometry</var></h3> 74</div> 75 76<p class="magick-description">Resize the image using data-dependent triangulation.</p> 77 78<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> 79option defaults to data-dependent triangulation. Use the <a 80href="command-line-options.html#filter">-filter</a> to choose a different resampling algorithm. 81Offsets, if present in the geometry string, are ignored, and the <a 82href="command-line-options.html#gravity">-gravity</a> option has no effect.</p> 83 84<div style="margin: auto;"> 85 <h3 class="magick-header"><a id="adaptive-sharpen"></a>-adaptive-sharpen <var>radius</var>[x<var>sigma</var>]</h3> 86</div> 87 88<p class="magick-description">Adaptively sharpen pixels, with increasing effect near edges.</p> 89 90<p>A Gaussian operator of the given radius and standard deviation 91(<var>sigma</var>) is used. If <var>sigma</var> is not given it 92defaults to 1.</p> 93 94<div style="margin: auto;"> 95 <h3 class="magick-header"><a id="adjoin"></a>-adjoin</h3> 96</div> 97 98<p class="magick-description">Join images into a single multi-image file.</p> 99 100<p>This option is enabled by default. An attempt is made to save all images of 101an image sequence into the given output file. However, some formats, such as 102JPEG and PNG, do not support more than one image per file, and in that case 103ImageMagick is forced to write each image as a separate file. As such, if 104more than one image needs to be written, the filename given is modified by 105adding a <a href="command-line-options.html#scene">-scene</a> number before the suffix, in order to 106make distinct names for each image. </p> 107 108<p>Use <a href="command-line-options.html#adjoin">+adjoin</a> to force each image to be written to 109separate files, whether or not the file format allows multiple images per file 110(for example, GIF, MIFF, and TIFF). </p> 111 112<p>Including a C-style integer format string in the output filename will 113automagically enable <a href="command-line-options.html#adjoin">+adjoin</a> and are used to specify 114where the <a href="command-line-options.html#scene">-scene</a> number is placed in the filenames. These 115strings, such as '<code>%d</code>' or '<code>%03d</code>', are familiar to those 116who have used the standard <code>printf()</code>' C-library function. As an 117example, the command</p> 118 119<pre> 120convert logo: rose: -morph 15 my%02dmorph.jpg 121</pre> 122 123<p>will create a sequence of 17 images (the two given plus 15 more created by 124<a href="command-line-options.html#morph">-morph</a>), named: my00morph.jpg, my01morph.jpg, 125my02morph.jpg, ..., my16morph.jpg. </p> 126 127<p>In summary, ImageMagick tries to write all images to one file, but will 128save to multiple files, if any of the following conditions exist...</p> 129<ol> 130<li>the output image's file format does not allow multi-image files,</li> 131<li>the <a href="command-line-options.html#adjoin">+adjoin</a> option is given, or</li> 132<li>a printf() integer format string (eg: "%d") is present in the output 133 filename.</li> 134</ol> 135 136 137<div style="margin: auto;"> 138 <h3 class="magick-header"><a id="affine"></a>-affine 139 <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> 140</div> 141 142<p class="magick-description">Set the drawing transformation matrix for combined rotating and scaling.</p> 143 144<p>This option sets a transformation matrix, for use by subsequent <a 145href="command-line-options.html#draw">-draw</a> or <a href="command-line-options.html#transform">-transform</a> options. </p> 146 147<p>The matrix entries are entered as comma-separated numeric values either in 148quotes or without spaces. </p> 149 150<p>Internally, the transformation matrix has 3x3 elements, but three of them 151are omitted from the input because they are constant. The new (transformed) 152coordinates (<var>x'</var>, <var>y'</var>) of a pixel at 153position (<var>x</var>, <var>y</var>) in the original 154image are calculated using the following matrix equation.</p> 155 156<p class="text-center"><img class="img-thumbnail" alt="affine transformation" src="../images/affine.png"/> </p> 157 158<p> The size of the resulting image is that of the smallest rectangle that 159contains the transformed source image. The parameters 160<var>t<sub>x</sub></var> and <var>t<sub>y</sub></var> 161subsequently shift the image pixels so that those that are moved out of the 162image area are cut off.</p> 163 164<p>The transformation matrix complies with the left-handed pixel coordinate 165system: positive <var>x</var> and <var>y</var> directions 166are rightward and downward, resp.; positive rotation is clockwise.</p> 167 168<p> If the translation coefficients <var>t<sub>x</sub></var> and 169<var>t<sub>y</sub></var> are omitted they default to 0,0. Therefore, 170four parameters suffice for rotation and scaling without translation.</p> 171 172<p>Scaling by the factors <var>s<sub>x</sub></var> and 173<var>s<sub>y</sub></var> in the <var>x</var> and <var>y</var> directions, 174respectively, is accomplished with the following.</p> 175 176<p>See <a href="command-line-options.html#transform">-transform</a>, and the <a 177href="command-line-options.html#distort">-distort</a> method '<code>Affineprojection</code> for more 178information </p> 179 180 181<pre> 182-affine <var>s<sub>x</sub></var>,0,0,<var>s<sub>y</sub></var> 183</pre> 184 185<p>Translation by a displacement (<var>t<sub>x</sub></var>, <var>t<sub>y</sub></var>) is accomplished like so:</p> 186 187<pre> 188-affine 1,0,0,1,<var>t<sub>x</sub></var>,<var>t<sub>y</sub></var> 189</pre> 190 191<p>Rotate clockwise about the origin (the upper left-hand corner) by an angle 192<var>a</var> by letting <var>c</var> = cos(<var>a</var>), <var>s</var> 193= sin(<var>a</var>), and using the following.</p> 194 195<pre> 196-affine <var>c</var>,<var>s</var>,-<var>s</var>,<var>c</var> 197</pre> 198 199<p>The cumulative effect of a sequence of <a href="command-line-options.html#affine" >-affine</a> 200transformations can be accomplished by instead by a single <a href="command-line-options.html#affine" 201>-affine</a> operation using the matrix equal to the product of the matrices 202of the individual transformations.</p> 203 204<p>An attempt is made to detect near-singular transformation matrices. If the 205matrix determinant has a sufficiently small absolute value it is rejected.</p> 206 207<div style="margin: auto;"> 208 <h3 class="magick-header"><a id="alpha"></a>-alpha <var>type</var></h3> 209</div> 210 211<p class="magick-description">Gives control of the alpha/matte channel of an image.</p> 212 213<p>Used to set a flag on an image indicating whether or not to use existing alpha 214channel 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> 215 216<dl class="dl-horizontal"> 217 <dt>Activate</dt> 218 <dd> 219 Enable the image's transparency channel. Note normally Set 220 should be used instead of this, unless you specifically need to 221 preserve existing (but specifically turned Off) transparency 222 channel. </dd> 223 224 <dt>Associate</dt> 225 <dd> 226 associate the alpha channel with the image.</dd> 227 228 <dt>Deactivate</dt> 229 <dd> 230 Disables the image's transparency channel. Does not delete or change the 231 existing data, just turns off the use of that data.</dd> 232 233 <dt>Disassociate</dt> 234 <dd> 235 disassociate the alpha channel from the image.</dd> 236 237 <dt>Set</dt> 238 <dd> 239 Activates the alpha/matte channel. If it was previously turned off 240 then it also resets the channel to opaque. If the image already had 241 the alpha channel turned on, it will have no effect.</dd> 242 243 <dt>Opaque</dt> 244 <dd> 245 Enables the alpha/matte channel and forces it to be fully opaque. 246 </dd> 247 248 <dt>Transparent</dt> 249 <dd> 250 Activates the alpha/matte channel and forces it to be fully 251 transparent. This effectively creates a fully transparent image the 252 same size as the original and with all its original RGB data still 253 intact, but fully transparent. </dd> 254 255 <dt>Extract</dt> 256 <dd> 257 Copies the alpha channel values into all the color channels and turns 258 'Off' the the image's transparency, so as to generate 259 a grayscale mask of the image's shape. The alpha channel data is left 260 intact just deactivated. This is the inverse of 'Copy'. 261 </dd> 262 263 <dt>Copy</dt> 264 <dd> 265 Turns 'On' the alpha/matte channel, then copies the 266 grayscale intensity of the image, into the alpha channel, converting 267 a grayscale mask into a transparent shaped mask ready to be colored 268 appropriately. The color channels are not modified. </dd> 269 270 <dt>Shape</dt> 271 <dd> 272 As per 'Copy' but also colors the resulting shape mask with 273 the current background color. That is the RGB color channels is 274 replaced, with appropriate alpha shape. 275 </dd> 276 277 <dt>Remove</dt> 278 <dd> 279 Composite the image over the background color. 280 </dd> 281 282 <dt>Background</dt> 283 <dd> 284 Set any fully-transparent pixel to the background color, while leaving 285 it fully-transparent. This can make some image file formats, such as 286 PNG, smaller as the RGB values of transparent pixels are more uniform, 287 and thus can compress better. 288 </dd> 289</dl> 290 291<p>Note that while the obsolete <code>+matte</code> operation was the 292same as "<code><a href="command-line-options.html#alpha" >-alpha</a> Off</code>", the <code> 293>-matte</code> operation was the same as "<code><a href="command-line-options.html#alpha" >-alpha</a> 294Set</code>" and not "<code><a href="command-line-options.html#alpha" >-alpha</a> On</code>". </p> 295 296<div style="margin: auto;"> 297 <h3 class="magick-header"><a id="alpha-color"></a>-alpha-color <var>color</var></h3> 298</div> 299 300<p class="magick-description">Specify the color to be used with the <a href="command-line-options.html#frame">-frame</a> option.</p> 301 302<p>The color is specified using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p> 303 304<p>The default matte color is <code>#BDBDBD</code>, <span 305style="background-color: #bdbdbd;">this shade of gray</span>.</p> 306 307<p>This is an IMv7 option, use <a href="command-line-options.html#mattecolor">mattecolor</a> with IMv6.</p> 308 309 310<div style="margin: auto;"> 311 <h3 class="magick-header"><a id="annotate"></a> 312 -annotate <var>degrees</var> <var>text</var><br /> 313 -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> 314</div> 315 316<p class="magick-description">Annotate an image with text</p> 317 318<p>This is a convenience for annotating an image with text. For more precise 319control over text annotations, use <a href="command-line-options.html#draw">-draw</a>.</p> 320 321 322<p>The values <var>Xdegrees</var> and <var>Ydegrees</var> 323control 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> 324 325<p>Using <a href="command-line-options.html#annotate">-annotate</a> <var>degrees</var> 326or <a href="command-line-options.html#annotate">-annotate</a> <var>degrees</var>x<var>degrees</var> produces an unsheared rotation of the text. The 327direction of the rotation is positive, which means a clockwise rotation if <var>degrees</var> is positive. (This conforms to the usual mathematical 328convention once it is realized that the positive <var>y</var>–direction is 329conventionally considered to be <var>downward</var> for images.)</p> 330 331<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 332equation.</p> 333 334<p class="text-center"><img class="img-thumbnail" alt="annotate transformation" src="../images/annotate.png"/></p> 335 336<p>If <var>t<sub>x</sub></var> and <var>t<sub>y</sub></var> are omitted, they default to 0. This makes the 337bottom-left of the text becomes the upper-left corner of the image, which is 338probably undesirable. Adding a <a href="command-line-options.html#gravity" >-gravity</a> option in this 339case leads to nice results.</p> 340 341<p>Text is any UTF-8 encoded character sequence. If <var>text</var> 342is of the form '@mytext.txt', the text is read from the file 343<code>mytext.txt</code>. Text in a file is taken literally; no embedded 344formatting characters are recognized.</p> 345 346<div style="margin: auto;"> 347 <h3 class="magick-header"><a id="antialias"></a>-antialias</h3> 348</div> 349 350<p class="magick-description">Enable/Disable of the rendering of anti-aliasing pixels when drawing fonts and lines.</p> 351 352<p>By default, objects (e.g. text, lines, polygons, etc.) are antialiased when 353drawn. Use <a href="command-line-options.html#antialias">+antialias</a> to disable the addition of 354antialiasing edge pixels. This will then reduce the number of colors added to 355an image to just the colors being directly drawn. That is, no mixed colors 356are added when drawing such objects. </p> 357 358<div style="margin: auto;"> 359 <h3 class="magick-header"><a id="append"></a>-append</h3> 360</div> 361 362<p class="magick-description">Join current images vertically or horizontally.</p> 363 364<p>This option creates a single longer image, by joining all the current 365images in sequence top-to-bottom. Use <a href="command-line-options.html#append">+append</a> to 366stack images left-to-right. </p> 367 368<p>If they are not of the same width, narrower images are padded with the 369current <a href="command-line-options.html#background">-background</a> color setting, and their 370position relative to each other can be controlled by the current <a 371href="command-line-options.html#gravity">-gravity</a> setting. </p> 372 373 374<div style="margin: auto;"> 375 <h3 class="magick-header"><a id="attenuate"></a>-attenuate <var>value</var></h3> 376</div> 377 378<p class="magick-description">Lessen (or intensify) when adding noise to an image.</p> 379 380<p>If unset the value is equivalent to 1.0, or a maximum noise addition</p> 381 382<div style="margin: auto;"> 383 <h3 class="magick-header"><a id="authenticate"></a>-authenticate <var>password</var></h3> 384</div> 385 386<p class="magick-description">Decrypt a PDF with a password.</p> 387 388<p>Use this option to supply a <var>password</var> for decrypting 389a PDF that has been encrypted using Microsoft Crypto API (MSC API). The 390encrypting using the MSC API is not supported.</p> 391 392<p>For a different encryption method, see <a href="command-line-options.html#encipher">-encipher</a> 393and <a href="command-line-options.html#decipher">-decipher</a>. </p> 394 395 396<div style="margin: auto;"> 397 <h3 class="magick-header"><a id="auto-gamma"></a>-auto-gamma</h3> 398</div> 399 400<p class="magick-description">Automagically adjust gamma level of image.</p> 401 402<p>This calculates the mean values of an image, then applies a calculated <a 403href="command-line-options.html#gamma" >-gamma</a> adjustment so that is the mean color exists in the 404image it will get a have a value of 50%. </p> 405 406<p>This means that any solid 'gray' image becomes 50% gray. </p> 407 408<p>This works well for real-life images with little or no extreme dark and 409light areas, but tend to fail for images with large amounts of bright sky or 410dark shadows. It also does not work well for diagrams or cartoon like images. 411</p> 412 413<p>It uses the <a href="command-line-options.html#channel" >-channel</a> setting, (including the 414'<var>sync</var>' flag for channel synchronization), to determine which color 415values is used and modified. As the default <a href="command-line-options.html#channel" 416>-channel</a> setting is '<var>RGB,sync</var>', channels are modified 417together by the same gamma value, preserving colors. </p> 418 419 420 421<div style="margin: auto;"> 422 <h3 class="magick-header"><a id="auto-level"></a>-auto-level</h3> 423</div> 424 425<p class="magick-description">Automagically adjust color levels of image.</p> 426 427<p>This is a 'perfect' image normalization operator. It finds the exact 428minimum and maximum color values in the image and then applies a <a 429href="command-line-options.html#level" >-level</a> operator to stretch the values to the full range of 430values. </p> 431 432<p>The operator is not typically used for real-life images, image scans, or 433JPEG format images, as a single 'out-rider' pixel can set a bad min/max values 434for the <a href="command-line-options.html#level" >-level</a> operation. On the other hand it is the 435right operator to use for color stretching gradient images being used to 436generate Color lookup tables, distortion maps, or other 'mathematically' 437defined images. </p> 438 439<p>The operator is very similar to the <a href="command-line-options.html#normalize">-normalize</a>, <a 440href="command-line-options.html#contrast-stretch" >-contrast-stretch</a>, and <a href="command-line-options.html#linear-stretch" 441>-linear-stretch</a> operators, but without 'histogram binning' or 'clipping' 442problems that these operators may have. That is <a href="command-line-options.html#auto-level" 443>-auto-level</a> is the perfect or ideal version these operators. </p> 444 445<p>It uses the <a href="command-line-options.html#channel" >-channel</a> setting, (including the 446special '<var>sync</var>' flag for channel synchronization), to determine 447which color values are used and modified. As the default <a 448href="command-line-options.html#channel" >+channel</a> setting is '<var>RGB,sync</var>', the 449'<var>sync</var>' ensures that the color channels will are modified 450together by the same gamma value, preserving colors, and ignoring 451transparency. </p> 452 453 454<div style="margin: auto;"> 455 <h3 class="magick-header"><a id="auto-orient"></a>-auto-orient</h3> 456</div> 457 458<p class="magick-description">adjusts an image so that its orientation is suitable for viewing (i.e. top-left orientation).</p> 459 460<p>This operator reads and resets the EXIF image profile setting 'Orientation' 461and then performs the appropriate 90 degree rotation on the image to orient 462the image, for correct viewing. </p> 463 464<p>This EXIF profile setting is usually set using a gravity sensor in digital 465camera, however photos taken directly downward or upward may not have an 466appropriate value. Also images that have been orientation 'corrected' without 467reseting this setting, may be 'corrected' again resulting in a incorrect 468result. If the EXIF profile was previously stripped, the <a 469href="command-line-options.html#auto-orient" >-auto-orient</a> operator will do nothing. </p> 470 471 472<div style="margin: auto;"> 473 <h3 class="magick-header"><a id="average"></a>-average</h3> 474</div> 475 476<p class="magick-description">Average a set of images.</p> 477 478<p>An error results if the images are not identically sized.</p> 479 480 481<div style="margin: auto;"> 482 <h3 class="magick-header"><a id="backdrop"></a>-backdrop</h3> 483</div> 484 485<p class="magick-description">Display the image centered on a backdrop.</p> 486 487<p>This backdrop covers the entire workstation screen and is useful for hiding 488other X window activity while viewing the image. The color of the backdrop is 489specified as the background color. The color is specified using the format 490described under the <a href="command-line-options.html#fill">-fill</a> option.</p> 491 492<div style="margin: auto;"> 493 <h3 class="magick-header"><a id="background"></a>-background <var>color</var></h3> 494</div> 495 496<p class="magick-description">Set the background color.</p> 497 498<p>The color is specified using the format described under the <a 499href="command-line-options.html#fill">-fill</a> option. The default background color (if none is 500specified or found in the image) is white.</p> 501 502<div style="margin: auto;"> 503 <h3 class="magick-header"><a id="bench"></a>-bench <var>iterations</var></h3> 504</div> 505 506<p class="magick-description">Measure performance.</p> 507 508<p>Repeat the entire command for the given number of <var>iterations</var> and report the user-time and elapsed time. For instance, 509consider the following command and its output. Modify the benchmark with the 510-duration to run the benchmark for a fixed number of seconds and -concurrent 511to run the benchmark in parallel (requires the OpenMP feature).</p> 512 513<pre> 514-> convert logo: -resize 200% -bench 5 logo.png 515Performance[1]: 5i 1.344ips 1.000e 3.710u 0:03.720 516Performance[2]: 5i 1.634ips 0.549e 3.890u 0:03.060 517Performance[3]: 5i 2.174ips 0.618e 3.190u 0:02.300 518Performance[4]: 5i 1.678ips 0.555e 3.810u 0:02.980 519Performance[4]: 5i 0.875657ips 6.880u 0:05.710 520</pre> 521 522<p>In this example, 5 iterations were completed at 2.174 iterations per 523second, using 3 threads and 3.190 seconds of the user allotted time, for 524a total elapsed time of 2.300 seconds.</p> 525 526<div style="margin: auto;"> 527 <h3 class="magick-header"><a id="bias"></a>-bias <var>value</var>{<var>%</var>}</h3> 528</div> 529 530<p class="magick-description">Add bias when convolving an image.</p> 531 532<p>This option shifts the output of <a href="command-line-options.html#convolve">‑convolve</a> so that 533positive and negative results are relative to the specified bias value. </p> 534 535<p>This is important for non-HDRI compilations of ImageMagick when dealing 536with convolutions that contain negative as well as positive values. This is 537especially the case with convolutions involving high pass filters or edge 538detection. Without an output bias, the negative values are clipped at 539zero.</p> 540 541<p>When using an ImageMagick with the HDRI compile-time setting, <a href="command-line-options.html#bias">‑bias</a> is not needed, as ImageMagick is able to store/handle any 542negative results without clipping to the color value range 543(0..QuantumRange).</p> 544 545<p>See the discussion on HDRI implementations of ImageMagick on the page <a 546href="high-dynamic-range.html" >High Dynamic-Range Images</a>. For more 547about HDRI go the ImageMagick <a 548href="http://www.imagemagick.org/Usage/basics/#hdri" >Usage</a> pages or this 549<a 550href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a> 551entry. </p> 552 553<div style="margin: auto;"> 554 <h3 class="magick-header"><a id="black-point-compensation"></a>-black-point-compensation</h3> 555</div> 556 557<p class="magick-description">Use black point compensation.</p> 558 559<div style="margin: auto;"> 560 <h3 class="magick-header"><a id="black-threshold"></a>-black-threshold <var>value</var>{<var>%</var>}</h3> 561</div> 562 563<p class="magick-description">Force to black all pixels below the threshold while leaving all pixels at or above the threshold unchanged.</p> 564 565<p> The threshold value can be given as a percentage or as an absolute integer 566value within [0, <var>QuantumRange</var>] corresponding to the 567desired <a href="command-line-options.html#channel">‑channel</a> value. See <a href="command-line-options.html#threshold">‑threshold</a>for more details on thresholds and resulting values. </p> 568 569 570<div style="margin: auto;"> 571 <h3 class="magick-header"><a id="blend"></a>-blend <var>geometry</var></h3> 572</div> 573 574<p class="magick-description">blend an image into another by the given absolute value or percent.</p> 575 576<p>Blend will average the images together ('plus') according to the 577percentages given and each pixels transparency. If only a single percentage 578value is given it sets the weight of the composite or 'source' image, while 579the background image is weighted by the exact opposite amount. That is a 580<code>-blend 30%</code> merges 30% of the 'source' image with 70% of the 581'destination' image. Thus it is equivalent to <code>-blend 30x70%</code>.</p> 582 583 584<div style="margin: auto;"> 585 <h3 class="magick-header"><a id="blue-primary"></a>-blue-primary <var>x</var>,<var>y</var></h3> 586</div> 587 588<p class="magick-description">Set the blue chromaticity primary point.</p> 589 590<div style="margin: auto;"> 591 <h3 class="magick-header"><a id="blue-shift"></a>-blue-shift <var>factor</var></h3> 592</div> 593 594<p class="magick-description">simulate a scene at nighttime in the moonlight. Start with a factor of 1.5</p> 595 596<div style="margin: auto;"> 597 598<div style="margin: auto;"> 599 <h3 class="magick-header"><a id="blur"></a>-blur <var>radius</var><br />-blur <var>radius</var>x<var>sigma</var></h3> 600</div> 601 602<p class="magick-description">Reduce image noise and reduce detail levels.</p> 603 604<p>Convolve the image with a Gaussian or normal distribution using the given 605<var >Sigma</var> value. The formula is:</p> 606 607<p class="text-center"><img class="img-thumbnail" alt="gaussian distribution" width="243px" height="42px" src="../images/gaussian-blur.png"/></p> 608 609<p>The <var >Sigma</var> value is the important argument, and 610determines the actual amount of blurring that will take place. </p> 611 612<p>The <var >Radius</var> is only used to determine the size of the 613array which will hold the calculated Gaussian distribution. It should be an 614integer. If not given, or set to zero, IM will calculate the largest possible 615radius that will provide meaningful results for the Gaussian distribution. 616</p> 617 618<p>The larger the <var >Radius</var> the slower the 619operation is. However too small a <var >Radius</var>, and sever 620aliasing effects may result. As a guideline, <var >Radius</var> 621should be at least twice the <var >Sigma</var> value, though three 622times will produce a more accurate result. </p> 623 624<p>This option differs from <a href="command-line-options.html#gaussian-blur">-gaussian-blur</a> simply 625by taking advantage of the separability properties of the distribution. Here 626we apply a single-dimensional Gaussian matrix in the horizontal direction, 627then repeat the process in the vertical direction.</p> 628 629<p>The <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting will determine how 630pixels which are outside the image proper are blurred into the final result. 631</p> 632 633 634<div style="margin: auto;"> 635 <h3 class="magick-header">-blur <var>Width</var>[x<var>Height</var>[+<var>Angle</var>]]</h3> 636</div> 637 638<p class="magick-description">Variably blur an image according to the overlay mapping.</p> 639 640<p>Each pixel in the overlaid region is replaced with an Elliptical Weighted 641Average (EWA) of the source image, scaled according to the grayscale 642mapping. </p> 643 644<p>The ellipse is weighted with sigma set to the given <var>Width</var> and <var >Height</var>. The <var >Height</var> 645defaults to the <var >Width</var> for a normal circular Gaussian 646weighting. The <var >Angle</var> will rotate the ellipse from 647horizontal clock-wise. </p> 648 649<p>The <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting will determine how 650pixels which are outside the image proper are blurred into the final result. 651</p> 652 653 654<div style="margin: auto;"> 655 <h3 class="magick-header"><a id="border"></a>-border <var>geometry</var></h3> 656</div> 657 658<p class="magick-description">Surround the image with a border of color. </p> 659 660<p>Set the width and height using the <var>size</var> portion of the 661<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 662ignored. </p> 663 664<p>As of IM 6.7.8-8, the <var>geometry</var> arguments behave as follows:</p> 665 666<dl class="dl-horizontal"> 667<dt><var>value</var></dt> 668<dd>value is added to both left/right and top/bottom</dd> 669<dt><var>value-x</var><kbd>x</kbd></dt> 670<dd>value-x is added only to left/right and top/bottom are unchanged</dd> 671<dt><kbd>x</kbd><var>value-y</var></dt> 672<dd>value-y is added only to top/bottom and left/right are unchanged</dd> 673<dt><var>value-x</var><kbd>x</kbd><var>value-y</var></dt> 674<dd>value-x is added to left/right and value-y added to top/bottom</dd> 675<dt><var>value-x</var><kbd>x</kbd>0</dt> 676<dd>value-x is added only to left/right and top/bottom are unchanged</dd> 677<dt>0<kbd>x</kbd><var>value-y</var></dt> 678<dd>value-y is added only to top/bottom and left/right are unchanged</dd> 679<dt><var>value</var>%</dt> 680<dd>value % of width is added to left/right and value % of height is added to top/bottom</dd> 681<dt><var>value-x</var><kbd>x</kbd>%</dt> 682<dd>value-x % of width is added to left/right and to top/bottom</dd> 683<dt>x<var>value-y</var>%</dt> 684<dd>value-y % of height is added to top/bottom and to left/right</dd> 685<dt><var>value-x</var>%<kbd>x</kbd><var>value-y</var>%</dt> 686<dd>value-x % of width is added to left/right and value-y % of height is added to top/bottom</dd> 687<dt><var>value-x</var>%<kbd>x</kbd>0%</dt> 688<dd>value-x % of width is added to left/right and top/bottom are unchanged</dd> 689<dt>0%<kbd>x</kbd><var>value-y</var>%</dt> 690<dd>value-y % of height is added to top/bottom and left/right are unchanged</dd> 691</dl> 692 693<p>Set the border color by preceding with the <a 694href="command-line-options.html#bordercolor">-bordercolor</a> setting.</p> 695 696<p>The <a href="command-line-options.html#border">-border</a> operation is affected by the current <a 697href="command-line-options.html#compose">-compose</a> setting and assumes that this is using the default 698'<code>Over</code>' composition method. It generates an image of the appropriate 699size colors by the current <a href="command-line-options.html#bordercolor">-bordercolor</a> before 700overlaying the original image in the center of this net image. This means that 701with the default compose method of '<code>Over</code>' any transparent parts may 702be replaced by the current <a href="command-line-options.html#bordercolor">-bordercolor</a> setting.</p> 703<p>See also the <a href="command-line-options.html#frame">-frame</a> option, which has more 704functionality.</p> 705 706<div style="margin: auto;"> 707 <h3 class="magick-header"><a id="bordercolor"></a>-bordercolor <var>color</var></h3> 708</div> 709 710<p class="magick-description">Set the border color.</p> 711 712<p>The color is specified using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p> 713 714<p>The default border color is <code>#DFDFDF</code>, <span style="background-color: #dfdfdf;">this shade of gray</span>.</p> 715 716<div style="margin: auto;"> 717 <h3 class="magick-header"><a id="borderwidth"></a>-borderwidth <var>geometry</var> </h3> 718</div> 719 720<p class="magick-description">Set the border width.</p> 721 722<div style="margin: auto;"> 723 <h3 class="magick-header"><a id="brightness-contrast"></a>-brightness-contrast <var>brightness</var><br />-brightness-contrast <var>brightness</var>{x<var>contrast</var>}{<var>%</var>}</h3> 724</div> 725 726<p class="magick-description">Adjust the brightness and/or contrast of the image.</p> 727 728<p>Brightness and Contrast values apply changes to the input image. They are 729not absolute settings. A brightness or contrast value of zero means no change. 730The range of values is -100 to +100 on each. Positive values increase the 731brightness or contrast and negative values decrease the brightness or contrast. 732To control only contrast, set the brightness=0. To control only brightness, 733set contrast=0 or just leave it off.</p> 734 735<p>You may also use <a href="command-line-options.html#fill">-channel</a> to control which channels to 736apply the brightness and/or contrast change. The default is to apply the same 737transformation to all channels.</p> 738 739<p>Brightness and Contrast arguments are converted to offset and slope of a 740linear transform and applied 741using <a href="command-line-options.html#fill">-function polynomial "slope,offset"</a>.</p> 742 743<p>The slope varies from 0 at contrast=-100 to almost vertical at 744contrast=+100. For brightness=0 and contrast=-100, the result are totally 745midgray. For brightness=0 and contrast=+100, the result will approach but 746not quite reach a threshold at midgray; that is the linear transformation 747is a very steep vertical line at mid gray.</p> 748 749<p>Negative slopes, i.e. negating the image, are not possible with this 750function. All achievable slopes are zero or positive.</p> 751 752<p>The offset varies from -0.5 at brightness=-100 to 0 at brightness=0 to +0.5 753at brightness=+100. Thus, when contrast=0 and brightness=100, the result is 754totally white. Similarly, when contrast=0 and brightness=-100, the result is 755totally black.</p> 756 757<p>As the range of values for the arguments are -100 to +100, adding the '%' 758symbol is no different than leaving it off.</p> 759 760<div style="margin: auto;"> 761 <h3 class="magick-header"><a id="cache"></a>-cache <var>threshold</var></h3> 762</div> 763 764<p class="magick-description">(This option has been replaced by the <a href='command-line-options.html#limit'>-limit</a> option).</p> 765 766<div style="margin: auto;"> 767 <h3 class="magick-header"><a 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> 768</div> 769 770<p class="magick-description">Canny edge detector uses a multi-stage algorithm to detect a wide range of edges in the image.</p> 771 772<p>The thresholds range from 0 to 100% (e.g. -canny 0x1+10%+30%) with {<var>+lower-percent</var>} < {<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> 773 774<div style="margin: auto;"> 775 <h3 class="magick-header"><a id="caption"></a>-caption <var>string</var></h3> 776</div> 777 778<p class="magick-description">Assign a caption to an image.</p> 779 780<p>This option sets the caption meta-data of an image read in after this 781option has been given. To modify a caption of images already in memory use 782"<code><a href="command-line-options.html#set">-set</a> caption</code>". </p> 783 784<p>The caption can contain special format characters listed in the <a 785href="escape.html">Format and 786Print Image Properties</a>. These attributes are expanded when the caption 787is finally assigned to the individual images. </p> 788 789<p>If the first character of <var>string</var> is <var>@</var>, the image caption is read from a file titled by the 790remaining characters in the string. Comments read in from a file are literal; 791no embedded formatting characters are recognized.</p> 792 793<p>Caption meta-data is not visible on the image itself. To do that use the 794<a href="command-line-options.html#annotate">-annotate</a> or <a href="command-line-options.html#draw">-draw</a> options 795instead.</p> 796 797<p>For example,</p> 798 799<pre> 800-caption "%m:%f %wx%h" bird.miff 801</pre> 802 803<p>produces an image caption of <code>MIFF:bird.miff 512x480</code> (assuming 804that the image <code>bird.miff</code> has a width of 512 and a height of 805480.</p> 806 807 808<div style="margin: auto;"> 809 <h3 class="magick-header"><a id="cdl"></a>-cdl <var>filename</var></h3> 810</div> 811 812<p class="magick-description">color correct with a color decision list.</p> 813 814<p>Here is an example color correction collection:</p> 815 816<pre> 817<?xml version="1.0" encoding="UTF-8"?> 818<ColorCorrectionCollection xmlns="urn:ASC:CDL:v1.2"> 819 <ColorCorrection id="cc06668"> 820 <SOPNode> 821 <Slope> 0.9 1.2 0.5 </Slope> 822 <Offset> 0.4 -0.5 0.6 </Offset> 823 <Power> 1.0 0.8 1.5 </Power> 824 </SOPNode> 825 <SATNode> 826 <Saturation> 0.85 </Saturation> 827 </SATNode> 828 </ColorCorrection> 829</ColorCorrectionCollection> 830</pre> 831 832<div style="margin: auto;"> 833 <h3 class="magick-header"><a id="channel"></a>-channel <var>type</var></h3> 834</div> 835 836<p class="magick-description">Specify those image color channels to which subsequent operators are limited.</p> 837 838<p>Choose from: <code>Red</code>, <code>Green</code>, <code>Blue</code>, 839<code>Alpha</code>, <code>Gray</code>, <code>Cyan</code>, <code>Magenta</code>, 840<code>Yellow</code>, <code>Black</code>, <code>Opacity</code>, 841<code>Index</code>, <code>RGB</code>, <code>RGBA</code>, <code>CMYK</code>, or 842<code>CMYKA</code>.</p> 843 844<p>The channels above can also be specified as a comma-separated list or can be 845abbreviated as a concatenation of the letters '<code>R</code>', '<code>G</code>', 846'<code>B</code>', '<code>A</code>', '<code>O</code>', '<code>C</code>', 847'<code>M</code>', '<code>Y</code>', '<code>K</code>'. 848 849For example, to only select the <code>Red</code> and <code>Blue</code> channels 850you can either use </p> 851<pre> 852-channel Red,Blue 853</pre> 854<p>or you can use the short hand form</p> 855<pre> 856-channel RB 857</pre> 858 859<p>All the channels that are present in an image can be specified using the 860special channel type <code>All</code>. Not all operators are 'channel capable', 861but generally any operators that are generally 'grey-scale' image operators, 862will understand this setting. See individual operator documentation. </p> 863 864<br/> 865 866<p>On top of the normal channel selection an extra flag can be specified, 867'<code>Sync</code>'. This is turned on by default and if set means that 868operators that understand this flag should perform: cross-channel 869synchronization of the channels. If not specified, then most grey-scale 870operators will apply their image processing operations to each individual 871channel (as specified by the rest of the <a href="command-line-options.html#channel">-channel</a> 872setting) completely independently from each other. </p> 873 874<p>For example for operators such as <a href="command-line-options.html#auto-level">-auto-level</a> and 875<a href="command-line-options.html#auto-gamma">-auto-gamma</a> the color channels are modified 876together in exactly the same way so that colors will remain in-sync. Without 877it being set, then each channel is modified separately and 878independently, which may produce color distortion. </p> 879 880<p>The <a href="command-line-options.html#morphology">-morphology</a> '<code>Convolve</code>' method 881and the <a href="command-line-options.html#compose">-compose</a> mathematical methods, also understands 882the '<code>Sync</code>' flag to modify the behavior of pixel colors according 883to the alpha channel (if present). That is to say it will modify the image 884processing with the understanding that fully-transparent colors should not 885contribute to the final result. </p> 886 887<p>Basically, by default, operators work with color channels in synchronous, and 888treats transparency as special, unless the <a href="command-line-options.html#channel">-channel</a> 889setting is modified so as to remove the effect of the '<code>Sync</code>' flag. 890How each operator does this depends on that operators current implementation. 891Not all operators understands this flag at this time, but that is changing. 892</p> 893 894<p>To print a complete list of channel types, use <a href="command-line-options.html#list">-list 895channel</a>.</p> 896 897<p>By default, ImageMagick sets <a href="command-line-options.html#channel">-channel</a> to the value 898'<code>RGBK,sync</code>', which specifies that operators act on all color 899channels except the transparency channel, and that all the color channels are 900to be modified in exactly the same way, with an understanding of transparency 901(depending on the operation being applied). The 'plus' form <a 902href="command-line-options.html#channel" >+channel</a> will reset the value back to this default. </p> 903 904<p>Options that are affected by the <a href="command-line-options.html#channel" >-channel</a> setting 905include the following. 906 907<a href="command-line-options.html#auto-gamma">-auto-gamma</a>, 908<a href="command-line-options.html#auto-level">-auto-level</a>, 909<a href="command-line-options.html#black-threshold">-black-threshold</a>, 910<a href="command-line-options.html#blur">-blur</a>, 911<a href="command-line-options.html#clamp">-clamp</a>, 912<a href="command-line-options.html#clut">-clut</a>, 913<a href="command-line-options.html#combine">-combine</a>, 914<a href="command-line-options.html#composite">-composite</a> (Mathematical compose methods only), 915<a href="command-line-options.html#convolve">-convolve</a>, 916<a href="command-line-options.html#contrast-stretch">-contrast-stretch</a>, 917<a href="command-line-options.html#evaluate">-evaluate</a>, 918<a href="command-line-options.html#function">-function</a>, 919<a href="command-line-options.html#fx">-fx</a>, 920<a href="command-line-options.html#gaussian-blur">-gaussian-blur</a>, 921<a href="command-line-options.html#hald-clut">-hald-clut</a>, 922<a href="command-line-options.html#motion-blur">-motion-blur</a>, 923<a href="command-line-options.html#morphology">-morphology</a>, 924<a href="command-line-options.html#negate">-negate</a>, 925<a href="command-line-options.html#normalize">-normalize</a>, 926<a href="command-line-options.html#ordered-dither">-ordered-dither</a>, 927<a href="command-line-options.html#radial-blur">-radial-blur</a>, 928<a href="command-line-options.html#random-threshold">-random-threshold</a>, 929<a href="command-line-options.html#separate">-separate</a>, 930<a href="command-line-options.html#threshold">-threshold</a>, and 931<a href="command-line-options.html#white-threshold">-white-threshold</a>. 932</p> 933 934<p>Warning, some operators behave differently when the <a href="command-line-options.html#channel" 935>+channel</a> default setting is in effect, verses ANY user defined <a 936href="command-line-options.html#channel" >-channel</a> setting (including the equivalent of the 937default). These operators have yet to be made to understand the newer 'Sync' 938flag. </p> 939 940<p>For example <a href="command-line-options.html#threshold">-threshold</a> will by default grayscale 941the image before thresholding, if no <a href="command-line-options.html#channel" >-channel</a> setting 942has been defined. This is not 'Sync flag controlled, yet. </p> 943 944<p>Also some operators such as <a href="command-line-options.html#blur">-blur</a>, <a 945href="command-line-options.html#gaussian-blur">-gaussian-blur</a>, will modify their handling of the 946color channels if the '<code>alpha</code>' channel is also enabled by <a 947href="command-line-options.html#channel" >-channel</a>. Generally this done to ensure that 948fully-transparent colors are treated as being fully-transparent, and thus any 949underlying 'hidden' color has no effect on the final results. Typically 950resulting in 'halo' effects. The newer <a href="command-line-options.html#morphology">-morphology</a> 951convolution equivalents however does have a understanding of the 'Sync' flag 952and will thus handle transparency correctly by default. </p> 953 954<p>As a alpha channel is optional within images, some operators will read the 955color channels of an image as a greyscale alpha mask, when the image has no 956alpha channel present, and the <a href="command-line-options.html#channel" >-channel</a> setting tells 957the operator to apply the operation using alpha channels. The <a 958href="command-line-options.html#clut">-clut</a> operator is a good example of this. </p> 959 960 961 962<div style="margin: auto;"> 963 <h3 class="magick-header"><a id="charcoal"></a>-charcoal <var>factor</var></h3> 964</div> 965 966<p class="magick-description">Simulate a charcoal drawing.</p> 967 968<div style="margin: auto;"> 969 <h3 class="magick-header"><a id="chop"></a>-chop <var>geometry</var></h3> 970</div> 971 972<p class="magick-description">Remove pixels from the interior of an image.</p> 973 974<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> 975and <var>height</var> given in the of the <var>size</var> 976portion of the <var>geometry</var> argument give the number of 977columns and rows to remove. The <var>offset</var> portion of 978the <var>geometry</var> argument is influenced by 979a <a href="command-line-options.html#gravity">-gravity</a> setting, if present.</p> 980 981<p>The <a href="command-line-options.html#chop">-chop</a> option removes entire rows and columns, 982and moves the remaining corner blocks leftward and upward to close the gaps.</p> 983 984<p>While it can remove internal rows and columns of pixels, it is more 985typically used with as <a href="command-line-options.html#gravity">-gravity</a> setting and zero 986offsets so as to remove a single edge from an image. Compare this to <a 987href="command-line-options.html#shave" >-shave</a> which removes equal numbers of pixels from opposite 988sides of the image. </p> 989 990<p>Using <a href="command-line-options.html#chop">-chop</a> effectively undoes the results of a <a 991href="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> 992 993<div style="margin: auto;"> 994 <h3 class="magick-header"><a id="clamp"></a>-clamp</h3> 995</div> 996 997<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> 998 999<div style="margin: auto;"> 1000 <h3 class="magick-header"><a id="clip"></a>-clip</h3> 1001</div> 1002 1003<p class="magick-description">Apply the clipping path if one is present.</p> 1004 1005<p>If a clipping path is present, it is applied to subsequent operations.</p> 1006 1007<p>For example, in the command</p> 1008 1009<pre> 1010convert cockatoo.tif -clip -negate negated.tif 1011</pre> 1012 1013<p>only the pixels within the clipping path are negated.</p> 1014 1015<p>The <a href="command-line-options.html#clip">-clip</a> feature requires SVG support. If the SVG 1016delegate library is not present, the option is ignored.</p> 1017 1018<p>Use <a href="command-line-options.html#clip">+clip</a> to disable clipping for subsequent operations.</p> 1019 1020<div style="margin: auto;"> 1021 <h3 class="magick-header"><a id="clip-mask"></a>-clip-mask</h3> 1022</div> 1023 1024<p class="magick-description">Clip the image as defined by this mask.</p> 1025 1026<p>Use the alpha channel of the current image as a mask. Any areas that is 1027white is not modified by any of the 'image processing operators' that follow, 1028until the mask is removed. Pixels in the black areas of the clip mask are 1029modified per the requirements of the operator. </p> 1030 1031<p>In some ways this is similar to (though not the same) as defining 1032a rectangular <a href="command-line-options.html#region" >-region</a>, or using the negative of the 1033mask (third) image in a three image <a href="command-line-options.html#composite" >-composite</a>, 1034operation. </p> 1035 1036<p>Use <a href="command-line-options.html#clip-mask">+clip-mask</a> to disable clipping for subsequent operations.</p> 1037 1038<div style="margin: auto;"> 1039 <h3 class="magick-header"><a id="clip-path"></a>-clip-path <var>id</var></h3> 1040</div> 1041 1042<p class="magick-description">Clip along a named path from the 8BIM profile.</p> 1043 1044<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> 1045 1046<p>Use <a href="command-line-options.html#clip-path">+clip-path</a> to disable clipping for subsequent operations.</p> 1047 1048<div style="margin: auto;"> 1049 <h3 class="magick-header"><a id="clone"></a>-clone <var>index(s)</var></h3> 1050</div> 1051 1052<p class="magick-description">make a clone of an image (or images).</p> 1053 1054<p>Inside parenthesis (where the operator is normally used) it will make a 1055clone of the images from the last 'pushed' image sequence, and adds them to 1056the end of the current image sequence. Outside parenthesis 1057(not recommended) it clones the images from the current image sequence. </p> 1058 1059<p>Specify the image by its index in the sequence. The first image is index 10600. Negative indexes are relative to the end of the sequence; for 1061example, <code>−1</code> 1062represents the last image of the sequence. Specify a range of images with a 1063dash (e.g. <code>0−4</code>). Separate multiple indexes with commas but no 1064spaces (e.g. <code>0,2,5</code>). A value of '<code>0−−1</code> will 1065effectively clone all the images. </p> 1066 1067<p>The <a href="command-line-options.html#clone">+clone</a> will simply make a copy of the last image 1068in the image sequence, and is thus equivalent to using a argument of 1069'<code>−1</code>'. </p> 1070 1071<div style="margin: auto;"> 1072 <h3 class="magick-header"><a id="clut"></a>-clut</h3> 1073</div> 1074 1075<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> 1076 1077<p>The second (LUT) image is ordinarily a gradient image containing the 1078histogram mapping of how each channel should be modified. Typically it is a 1079either a single row or column image of replacement color values. If larger 1080than a single row or column, values are taken from a diagonal line from 1081top-left to bottom-right corners.</p> 1082 1083<p>The lookup is further controlled by the <a 1084href="command-line-options.html#interpolate">-interpolate</a> setting, which is especially handy for an 1085LUT which is not the full length needed by the ImageMagick installed Quality 1086(Q) level. Good settings for this are the '<code>bilinear</code>' and 1087'<code>bicubic</code>' interpolation settings, which give smooth color 1088gradients, and the '<code>integer</code>' setting for a direct, unsmoothed 1089lookup of color values. </p> 1090 1091<p>This operator is especially suited to replacing a grayscale image with a 1092specific color gradient from the CLUT image. </p> 1093 1094<p>Only the channel values defined by the <a href="command-line-options.html#channel">-channel</a> 1095setting will have their values replaced. In particular, since the default <a 1096href="command-line-options.html#channel">-channel</a> setting is <code>RGB</code>, this means that 1097transparency (alpha/matte channel) is not affected, unless the <a 1098href="command-line-options.html#channel">-channel</a> setting is modified. When the alpha channel is 1099set, it is treated by the <a href="command-line-options.html#clut" >-clut</a> operator in the same way 1100as the other channels, implying that alpha/matte values are replaced using the 1101alpha/matte values of the original image. </p> 1102 1103<p>If either the image being modified, or the lookup image, contains no 1104transparency (i.e. <a href="command-line-options.html#alpha" >-alpha</a> is turned 'off') but the <a 1105href="command-line-options.html#channel">-channel</a> setting includes alpha replacement, then it is 1106assumed that image represents a grayscale gradient which is used for the 1107replacement alpha values. That is you can use a grayscale CLUT image to 1108adjust a existing images alpha channel, or you can color a grayscale image 1109using colors form CLUT containing the desired colors, including transparency. 1110</p> 1111 1112<p>See also <a href="command-line-options.html#hald-clut" >-hald-clut</a> which replaces colors 1113according to the lookup of the full color RGB value from a 2D representation 1114of a 3D color cube. </p> 1115 1116 1117<div style="margin: auto;"> 1118 <h3 class="magick-header"><a id="coalesce"></a>-coalesce</h3> 1119</div> 1120 1121<p class="magick-description">Fully define the look of each frame of an GIF animation sequence, to form a 'film strip' animation.</p> 1122 1123<p>Overlay each image in an image sequence according to 1124its <a href="command-line-options.html#dispose">-dispose</a> meta-data, to reproduce the look of 1125an animation at each point in the animation sequence. All images should be 1126the same size, and are assigned appropriate GIF disposal settings for the 1127animation to continue working as expected as a GIF animation. Such frames 1128are more easily viewed and processed than the highly optimized GIF overlay 1129images. </p> 1130 1131<p>The animation can be re-optimized after processing using 1132the <a href="command-line-options.html#layers">-layers</a> method '<code>optimize</code>', although 1133there is no guarantee that the restored GIF animation optimization is 1134better than the original. </p> 1135 1136 1137<div style="margin: auto;"> 1138 <h3 class="magick-header"><a id="colorize"></a>-colorize <var>value</var></h3> 1139</div> 1140 1141<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> 1142 1143<p>Specify the amount of colorization as a percentage. Separate colorization 1144values can be applied to the red, green, and blue channels of the image with 1145a comma-delimited list of colorization 1146values (e.g., <code>-colorize 0,0,50</code>).</p> 1147 1148<div style="margin: auto;"> 1149 <h3 class="magick-header"><a id="colormap"></a>-colormap <var>type</var></h3> 1150</div> 1151 1152<p class="magick-description">Define the colormap type.</p> 1153 1154<p>The <var>type</var> can be <code>shared</code> or <code>private</code>.</p> 1155 1156<p>This option only applies when the default X server visual 1157is <code>PseudoColor</code> or <code>GrayScale</code>. Refer 1158to <a href="command-line-options.html#visual">-visual</a> for more details. By default, 1159a shared colormap is allocated. The image shares colors with 1160other X clients. Some image colors could be approximated, 1161therefore your image may look very different than intended. 1162If <code>private</code> is chosen, the image colors appear exactly 1163as they are defined. However, other clients may go <var>technicolor</var> 1164when the image colormap is installed.</p> 1165 1166<div style="margin: auto;"> 1167 <h3 class="magick-header"><a id="colors"></a>-colors <var>value</var></h3> 1168</div> 1169 1170<p class="magick-description">Set the preferred number of colors in the image.</p> 1171 1172<p>The actual number of colors in the image may be less than your request, 1173but never more. Note that this a color reduction option. Images with fewer 1174unique colors than specified by <var>value</var> will have any 1175duplicate or unused colors removed. The ordering of an existing color 1176palette may be altered. When converting an image from color to grayscale, 1177it is more efficient to convert the image to the gray colorspace before 1178reducing the number of colors. Refer to 1179the <a href="quantize.html"> 1180color reduction algorithm</a> for more details.</p> 1181 1182<div style="margin: auto;"> 1183 <h3 class="magick-header"><a id="color-matrix"></a>-color-matrix <var>matrix</var></h3> 1184</div> 1185 1186<p class="magick-description">apply color correction to the image.</p> 1187 1188<p>This option permits saturation changes, hue rotation, luminance to alpha, 1189and various other effects. Although variable-sized transformation matrices 1190can be used, typically one uses a 5x5 matrix for an RGBA image and a 6x6 1191for CMYKA (or RGBA with offsets). The matrix is similar to those used by 1192Adobe Flash except offsets are in column 6 rather than 5 (in support of 1193CMYKA images) and offsets are normalized (divide Flash offset by 255).</p> 1194 1195<p>As an example, to add contrast to an image with offsets, try this command:</p> 1196 1197<pre> 1198convert kittens.jpg -color-matrix \ 1199 " 1.5 0.0 0.0 0.0, 0.0, -0.157 \ 1200 0.0 1.5 0.0 0.0, 0.0, -0.157 \ 1201 0.0 0.0 1.5 0.0, 0.0, -0.157 \ 1202 0.0 0.0 0.0 1.0, 0.0, 0.0 \ 1203 0.0 0.0 0.0 0.0, 1.0, 0.0 \ 1204 0.0 0.0 0.0 0.0, 0.0, 1.0" kittens.png 1205</pre> 1206<div style="margin: auto;"> 1207 <h3 class="magick-header"><a id="colorspace"></a>-colorspace <var>value</var></h3> 1208</div> 1209 1210<p class="magick-description">Set the image colorspace.</p> 1211 1212<p>Choices are:</p> 1213 1214<pre> 1215CMY CMYK Gray HCL 1216HCLp HSB HSI HSL 1217HSV HWB Lab LCHab 1218LCHuv LMS Log Luv 1219OHTA Rec601YCbCr Rec709YCbCr RGB 1220scRGB sRGB Transparent xyY 1221XYZ YCbCr YCC YDbDr 1222YIQ YPbPr YUV 1223</pre> 1224 1225<p>To print a complete list of colorspaces, use <a href="command-line-options.html#list">-list colorspace</a>.</p> 1226 1227<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> 1228 1229<table class="table table-condensed table-striped"> 1230 <caption>Conversion of RGB to Other Color Spaces</caption> 1231 <tr><th valign="middle">CMY</th></tr> 1232 <tr><td valign="middle">C=<var>QuantumRange</var>−R</td></tr> 1233 <tr><td valign="middle">M=<var>QuantumRange</var>−G</td></tr> 1234 <tr><td valign="middle">Y=<var>QuantumRange</var>−B</td></tr> 1235 <tr><th valign="middle">CMYK — starts with CMY from above</th></tr> 1236 <tr><td valign="middle">K=min(C,Y,M)</td></tr> 1237 <tr><td valign="middle">C=<var>QuantumRange</var>*(C−K)/(<var>QuantumRange</var>−K)</td></tr> 1238 <tr><td valign="middle">M=<var>QuantumRange</var>*(M−K)/(<var>QuantumRange</var>−K)</td></tr> 1239 <tr><td valign="middle">Y=<var>QuantumRange</var>*(Y−K)/(<var>QuantumRange</var>−K)</td></tr> 1240 1241 <tr><th valign="middle">Gray</th></tr> 1242 <tr><td valign="middle">Gray = 0.298839*R+0.586811*G+0.114350*B</td></tr> 1243 1244 <tr><th valign="middle">HSB — Hue, Saturation, Brightness; like a cone peak downward</th></tr> 1245 <tr><td valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr> 1246 <tr><td valign="middle">S=distance from axis outward</td></tr> 1247 <tr><td valign="middle">B=distance along axis from bottom upward; B=max(R,G,B); <var>intensity-like</var></td></tr> 1248 1249 <tr><th valign="middle">HSL — Hue, Saturation, Lightness; like a double cone end-to-end with peaks at very top and bottom</th></tr> 1250 <tr><td valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr> 1251 <tr><td valign="middle">S=distance from axis outward</td></tr> 1252 <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> 1253 1254 <tr><th valign="middle">HWB — Hue, Whiteness, Blackness</th></tr> 1255 <tr><td valign="middle">Hue (complicated equation)</td></tr> 1256 <tr><td valign="middle">Whiteness (complicated equation)</td></tr> 1257 <tr><td valign="middle">Blackness (complicated equation)</td></tr> 1258 1259 <tr><th valign="middle">LAB</th></tr> 1260 <tr><td valign="middle">L (complicated equation relating X,Y,Z)</td></tr> 1261 <tr><td valign="middle">A (complicated equation relating X,Y,Z)</td></tr> 1262 <tr><td valign="middle">B (complicated equation relating X,Y,Z)</td></tr> 1263 1264 <tr><th valign="middle">LOG</th></tr> 1265 <tr><td valign="middle">I1 (complicated equation involving logarithm of R)</td></tr> 1266 <tr><td valign="middle">I2 (complicated equation involving logarithm of G)</td></tr> 1267 <tr><td valign="middle">I3 (complicated equation involving logarithm of B)</td></tr> 1268 1269 <tr><th valign="middle">OHTA — approximates principal components transformation</th></tr> 1270 <tr><td valign="middle">I1=0.33333*R+0.33334*G+0.33333*B; <var>intensity-like</var></td></tr> 1271 <tr><td valign="middle">I2=(0.50000*R+0.00000*G−0.50000*B)*(<var>QuantumRange</var>+1)/2</td></tr> 1272 <tr><td valign="middle">I3=(−0.25000*R+0.50000*G−0.25000*B)*(<var>QuantumRange</var>+1)/2</td></tr> 1273 1274 <tr><th valign="middle">Rec601Luma</th></tr> 1275 <tr><td valign="middle">Gray = 0.298839*R+0.586811*G+0.114350*B</td></tr> 1276 1277 <tr><th valign="middle">Rec601YCbCr</th></tr> 1278 <tr><td valign="middle">Y=0.2988390*R+0.5868110*G+0.1143500*B; <var>intensity-like</var></td></tr> 1279 <tr><td valign="middle">Cb=(−0.168736*R-0.331264*G+0.500000*B)*(<var>QuantumRange</var>+1)/2</td></tr> 1280 <tr><td valign="middle">Cr=(0.500000*R−0.418688*G−0.081312*B)*(<var>QuantumRange</var>+1)/2</td></tr> 1281 1282 <tr><th valign="middle">Rec709Luma</th></tr> 1283 <tr><td valign="middle">Gray=0.212656*R+0.715158*G+0.072186*B</td></tr> 1284 1285 <tr><th valign="middle">Rec709YCbCr</th></tr> 1286 <tr><td valign="middle">Y=0.212656*R+0.715158*G+0.072186*B; <var>intensity-like</var></td></tr> 1287 <tr><td valign="middle">Cb=(−0.114572*R−0.385428*G+0.500000*B)+(<var>QuantumRange</var>+1)/2</td></tr> 1288 <tr><td valign="middle">Cr=(0.500000*R−0.454153*G−0.045847*B)+(<var>QuantumRange</var>+1)/2</td></tr> 1289 1290 <tr><th valign="middle">sRGB</th></tr> 1291 <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> 1292 <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> 1293 <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> 1294 1295 <tr><th valign="middle">XYZ</th></tr> 1296 <tr><td valign="middle">X=0.4124564*R+0.3575761*G+0.1804375*B</td></tr> 1297 <tr><td valign="middle">Y=0.2126729*R+0.7151522*G+0.0721750*B</td></tr> 1298 <tr><td valign="middle">Z=0.0193339*R+0.1191920*G+0.9503041*B</td></tr> 1299 1300 <tr><th valign="middle">YCC</th></tr> 1301 <tr><td valign="middle">Y=(0.298839*R+0.586811*G+0.114350*B) (with complicated scaling); <var>intensity-like</var></td></tr> 1302 <tr><td valign="middle">C1=(−0.298839*R−0.586811*G+0.88600*B) (with complicated scaling)</td></tr> 1303 <tr><td valign="middle">C2=(0.70100*R−0.586811*G−0.114350*B) (with complicated scaling)</td></tr> 1304 1305 <tr><th valign="middle">YCbCr</th></tr> 1306 <tr><td valign="middle">Y=0.2988390*R+0.5868110*G+0.1143500*B; <var>intensity-like</var></td></tr> 1307 <tr><td valign="middle">Cb=(−0.168736*R−0.331264*G+0.500000*B)*(<var>QuantumRange</var>+1)/2</td></tr> 1308 <tr><td valign="middle">Cr=(0.500000*R−0.418688*G−0.081312*B)*(<var>QuantumRange</var>+1)/2</td></tr> 1309 1310 <tr><th valign="middle">YIQ</th></tr> 1311 <tr><td valign="middle">Y=0.298839*R+0.586811*G+0.114350*B; <var>intensity-like</var></td></tr> 1312 <tr><td valign="middle">I=(0.59600*R−0.27400*G−0.32200*B)*(<var>QuantumRange</var>+1)/2</td></tr> 1313 <tr><td valign="middle">Q=(0.21100*R−0.52300*G+0.31200*B)*(<var>QuantumRange</var>+1)/2</td></tr> 1314 1315 <tr><th valign="middle">YPbPr</th></tr> 1316 <tr><td valign="middle">Y=0.2988390*R+0.5868110*G+0.1143500*B; <var>intensity-like</var></td></tr> 1317 <tr><td valign="middle">Pb=(−0.168736*R−0.331264*G+0.500000*B)*(<var>QuantumRange</var>+1)/2</td></tr> 1318 <tr><td valign="middle">Pr=(0.500000*R−0.418688*G−0.081312*B)*(<var>QuantumRange</var>+1)/2</td></tr> 1319 1320 <tr><th valign="middle">YUV</th></tr> 1321 <tr><td valign="middle">Y=0.298839*R+0.586811*G+0.114350*B; <var>intensity-like</var></td></tr> 1322 <tr><td valign="middle">U=(−0.14740*R−0.28950*G+0.43690*B)*(<var>QuantumRange</var>+1)/2</td></tr> 1323 <tr><td valign="middle">V=(0.61500*R−0.51500*G−0.10000*B)*(<var>QuantumRange</var>+1)/2</td></tr> 1324</table> 1325 1326<p>Note the scRGB colorspace requires HDRI support otherwise it behaves just like linear RGB.</p> 1327 1328<div style="margin: auto;"> 1329 <h3 class="magick-header"><a id="combine"></a>-combine</h3> 1330</div> 1331 1332<p class="magick-description">Combine one or more images into a single image.</p> 1333 1334<p>The channels (previously set by <a href="command-line-options.html#channel">-channel</a>) of the 1335combined image are taken from the grayscale values of each image in the 1336sequence, in order. For the default -channel setting of <code>RGB</code>, this 1337means the first image is assigned to the <code>Red</code> channel, the second 1338to the <code>Green</code> channel, the third to the <code>Blue</code>.</p> 1339 1340<p>This option can be thought of as the inverse to <a 1341href="command-line-options.html#separate">-separate</a>, so long as the channel settings are the same. 1342Thus, in the following example, the final image should be a copy of the 1343original. </p> 1344 1345<pre> 1346convert original.png -channel RGB -separate sepimage.png 1347convert sepimage-0.png sepimage-1.png sepimage-2.png -channel RGB \ 1348 -combine imagecopy.png 1349</pre> 1350 1351<div style="margin: auto;"> 1352 <h3 class="magick-header"><a id="comment"></a>-comment <var>string</var></h3> 1353</div> 1354 1355<p class="magick-description">Embed a comment in an image.</p> 1356 1357<p>This option sets the comment meta-data of an image read in after this 1358option has been given. To modify a comment of images already in memory use 1359"<code><a href="command-line-options.html#set">-set</a> comment</code>". </p> 1360 1361<p>The comment can contain special format characters listed in the <a 1362href="escape.html">Format and 1363Print Image Properties</a>. These attributes are expanded when the comment 1364is finally assigned to the individual images. </p> 1365 1366<p>If the first character of <var>string</var> is <var>@</var>, the image comment is read from a file titled by the 1367remaining characters in the string. Comments read in from a file are literal; 1368no embedded formatting characters are recognized.</p> 1369 1370<p>Comment meta-data are not visible on the image itself. To do that use the 1371<a href="command-line-options.html#annotate">-annotate</a> or <a href="command-line-options.html#draw">-draw</a> options 1372instead.</p> 1373 1374<p>For example,</p> 1375 1376<pre> 1377-comment "%m:%f %wx%h" bird.miff 1378</pre> 1379 1380<p>produces an image comment of <code>MIFF:bird.miff 512x480</code> (assuming 1381that the image <code>bird.miff</code> has a width of 512 and a height of 1382480.</p> 1383 1384<div style="margin: auto;"> 1385 <h3 class="magick-header"><a id="compare"></a>-compare</h3> 1386</div> 1387 1388<p class="magick-description">mathematically and visually annotate the difference between an image and its reconstruction</p> 1389 1390<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> 1391 1392<pre> 1393convert image.png reference.png -metric RMSE -compare \ <br/> difference.png 1394</pre> 1395 1396<p>To get the metric value use the string format "%[distortion]".</p> 1397 1398<pre> 1399convert image.png reference.png -metric RMSE -compare -format \ 1400 "%[distortion]" info: 1401</pre> 1402 1403<div style="margin: auto;"> 1404 <h3 class="magick-header"><a id="complex"></a>-complex <var>operator</var></h3> 1405</div> 1406 1407<p class="magick-description">perform complex mathematics on an image sequence</p> 1408 1409Choose from these operators: 1410 1411<pre> 1412add 1413conjugate 1414divide 1415magnitude-phase 1416multiply 1417real-imaginary 1418subtract 1419</pre> 1420 1421<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> 1422 1423<div style="margin: auto;"> 1424 <h3 class="magick-header"><a id="compose"></a>-compose <var>operator</var></h3> 1425</div> 1426 1427<p class="magick-description">Set the type of image composition.</p> 1428 1429<p>See <a href="compose.html">Alpha Compositing</a> for 1430a detailed discussion of alpha compositing.</p> 1431 1432<p>This setting effects image processing operators that merge two (or more) 1433images together in some way. This includes the operators, 1434<a href="command-line-options.html#composite">-compare</a>, 1435<a href="command-line-options.html#composite">-composite</a>, 1436<a href="command-line-options.html#layers">-layers</a> composite, 1437<a href="command-line-options.html#flatten">-flatten</a>, 1438<a href="command-line-options.html#mosaic">-mosaic</a>, 1439<a href="command-line-options.html#layers">-layers</a> merge, 1440<a href="command-line-options.html#border">-border</a>, 1441<a href="command-line-options.html#frame">-frame</a>, 1442and <a href="command-line-options.html#extent">-extent</a>. </p> 1443 1444<p>It is also one of the primary options for the "<code>composite</code>" 1445command. </p> 1446 1447 1448<div style="margin: auto;"> 1449 <h3 class="magick-header"><a id="composite"></a>-composite</h3> 1450</div> 1451 1452<p class="magick-description">Perform alpha composition on two images and an optional mask</p> 1453 1454<p>Take the first image 'destination' and overlay the second 'source' image 1455according to the current <a href="command-line-options.html#compose">-compose</a> setting. The location 1456of the 'source' or 'overlay' image is controlled according to <a 1457href="command-line-options.html#gravity" >-gravity</a>, and <a href="command-line-options.html#geometry" >-geometry</a> 1458settings. </p> 1459 1460<p>If a third image is given this is treated as a grayscale blending 'mask' image 1461relative to the first 'destination' image. This mask is blended with the 1462source image. However for the '<code>displace</code>' compose method, the 1463mask is used to provide a separate Y-displacement image instead. </p> 1464 1465<p>If a <a href="command-line-options.html#compose">-compose</a> method requires extra numerical 1466arguments or flags these can be provided by setting the <a 1467href="command-line-options.html#set">-set</a> '<code>option:compose:args</code>' 1468appropriately for the compose method. </p> 1469 1470<p>Some <a href="command-line-options.html#compose">-compose</a> methods can modify the 'destination' 1471image outside the overlay area. You can disable this by setting the special <a 1472href="command-line-options.html#set">-set</a> '<code>option:compose:outside-overlay</code>' 1473to '<code>false</code>'. </p> 1474 1475<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> 1476 1477 1478<div style="margin: auto;"> 1479 <h3 class="magick-header"><a id="compress"></a>-compress <var>type</var></h3> 1480</div> 1481 1482<p class="magick-description">Use pixel compression specified by <var>type</var> when writing the image.</p> 1483 1484<p>Choices are: <code>None</code>, <code>BZip</code>, <code 1485>Fax</code>, <code>Group4</code>, <code 1486>JPEG</code>, <code>JPEG2000</code>, <code 1487>Lossless</code>, <code>LZW</code>, <code 1488>RLE</code> or <code>Zip</code>.</p> 1489 1490<p>To print a complete list of compression types, use <a href="command-line-options.html#list">-list 1491compress</a>.</p> 1492 1493<p>Specify <a href="command-line-options.html#compress">+compress</a> to store the binary image in an 1494uncompressed format. The default is the compression type of the specified 1495image file.</p> 1496 1497<p>If <code>LZW</code> compression is specified but LZW compression has not been 1498enabled, the image data is written in an uncompressed LZW format that can be 1499read by LZW decoders. This may result in larger-than-expected GIF files.</p> 1500 1501<p><code>Lossless</code> refers to lossless JPEG, which is only available if the 1502JPEG library has been patched to support it. Use of lossless JPEG is generally 1503not recommended.</p> 1504 1505<p> 1506When writing an ICO file, you may request that the images be encoded in 1507PNG format, by specifying <code>Zip</code> compression.</p> 1508 1509<p> 1510When writing a JNG file, specify <code>Zip</code> compression to request that 1511the alpha channel be encoded in PNG "IDAT" format, or <code>JPEG</code> 1512to request that it be encoded in JPG "JDAA" format.</p> 1513 1514<p>Use the <a href="command-line-options.html#quality">-quality</a> option to set the compression level 1515to be used by JPEG, PNG, MIFF, and MPEG encoders. 1516Use the <a href="command-line-options.html#sampling-factor">-sampling-factor</a> option to set the 1517sampling factor to be used by JPEG, MPEG, and YUV encoders for down-sampling 1518the chroma channels.</p> 1519 1520<div style="margin: auto;"> 1521 <h3 class="magick-header"><a id="connected-components"></a>-connected-components <var>connectivity</var></h3> 1522</div> 1523 1524<p class="magick-description"><a href="connected-components.html">connected-components</a> labeling detects connected regions in an image, choose from 4 or 8 way connectivity.</p> 1525 1526<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> 1527 1528<div style="margin: auto;"> 1529 <h3 class="magick-header"><a id="contrast"></a>-contrast</h3> 1530</div> 1531 1532<p class="magick-description">Enhance or reduce the image contrast.</p> 1533 1534<p>This option enhances the intensity differences between the lighter and 1535darker elements of the image. Use <a href="command-line-options.html#contrast">-contrast</a> to enhance 1536the image or <a href="command-line-options.html#contrast">+contrast</a> to reduce the image 1537contrast.</p> 1538 1539<p>For a more pronounced effect you can repeat the option:</p> 1540 1541<pre> 1542convert rose: -contrast -contrast rose_c2.png 1543</pre> 1544 1545<div style="margin: auto;"> 1546 <h3 class="magick-header"><a 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> 1547</div> 1548 1549<p class="magick-description">Increase the contrast in an image by <var>stretching</var> the range of intensity values.</p> 1550 1551<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 1552<var >black-point %</var> pixels and white-out at most <var>white-point %</var> pixels.</p> 1553 1554<p>Prior to ImageMagick 6.4.7-0, <a href="command-line-options.html#contrast-stretch" 1555>-contrast-stretch</a> will black-out at most <var>black-point</var> pixels and white-out at most <var >total pixels 1556minus 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> 1557 1558<p>Note that <code>-contrast-stretch 0</code> will modify the image such that 1559the 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 1560clipping at either end. This is not the same as <a href="command-line-options.html#normalize" 1561>-normalize</a>, which is equivalent to <code>-contrast-stretch 0.15x0.05%</code> (or 1562prior to ImageMagick 6.4.7-0, <code>-contrast-stretch 2%x99%</code>).</p> 1563 1564<p>Internally operator works by creating a histogram bin, and then uses that 1565bin to modify the image. As such some colors may be merged together when they 1566originally fell into the same 'bin'. </p> 1567 1568<p>All the channels are normalized in concert by the same amount so as to 1569preserve color integrity, when the default <a href="command-line-options.html#channel" >+channel</a> 1570setting is in use. Specifying any other <a href="command-line-options.html#channel" >-channel</a> 1571setting will normalize the RGB channels independently.</p> 1572 1573<p>See also <a href="command-line-options.html#auto-level" >-auto-level</a> for a 'perfect' 1574normalization of mathematical images. </p> 1575 1576<p>This operator is under review for re-development. </p> 1577 1578 1579<div style="margin: auto;"> 1580 <h3 class="magick-header"><a id="convolve"></a>-convolve <var>kernel</var></h3> 1581</div> 1582 1583<p class="magick-description">Convolve an image with a user-supplied convolution kernel.</p> 1584 1585<p>The <var>kernel</var> is a matrix specified as 1586a comma-separated list of integers (with no spaces), ordered left-to right, 1587starting with the top row. Presently, only odd-dimensioned kernels are 1588supported, and therefore the number of entries in the specified <var>kernel</var> must be 3<sup>2</sup>=9, 5<sup>2</sup>=25, 15897<sup>2</sup>=49, etc. </p> 1590 1591<p>Note that the <a href="command-line-options.html#convolve">‑convolve</a> operator supports the <a href="command-line-options.html#bias">‑bias</a> setting. This option shifts the convolution so that 1592positive and negative results are relative to a user-specified bias value. 1593This is important for non-HDRI compilations of ImageMagick when dealing with 1594convolutions that contain negative as well as positive values. This is 1595especially the case with convolutions involving high pass filters or edge 1596detection. Without an output bias, the negative values is clipped at zero. 1597</p> 1598 1599<p>When using an ImageMagick with the HDRI compile-time setting, <a href="command-line-options.html#bias">‑bias</a> is not needed, as ImageMagick is able to store/handle any 1600negative results without clipping to the color value range (0..QuantumRange). 1601See the discussion on HDRI implementations of ImageMagick on the page <a 1602href="high-dynamic-range.html">High 1603Dynamic-Range Images</a>. For more about HDRI go the ImageMagick <a 1604href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this 1605<a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a> 1606entry. </p> 1607 1608 1609<div style="margin: auto;"> 1610 <h3 class="magick-header"><a id="copy"></a>-copy <var>geometry</var> <var>offset</var></h3> 1611</div> 1612 1613<p class="magick-description">copy pixels from one area of an image to another.</p> 1614 1615<div style="margin: auto;"> 1616 <h3 class="magick-header"><a id="crop"></a>-crop <var>geometry</var>{<var>@</var>}{<var>!</var>}</h3> 1617</div> 1618 1619<p class="magick-description">Cut out one or more rectangular regions of the image.</p> 1620 1621<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 1622 1623<p>The <var>width</var> and <var>height</var> of the <var>geometry</var> argument give the size of the image that remains 1624after cropping, and <var>x</var> and <var>y</var> in the 1625<var>offset</var> (if present) gives the location of the top left 1626corner of the cropped image with respect to the original image. To specify the 1627amount to be removed, use <a href="command-line-options.html#shave">-shave</a> instead.</p> 1628 1629<p>If the <var>x</var> and <var>y</var> offsets are 1630present, a single image is generated, consisting of the pixels from the 1631cropping region. The offsets specify the location of the upper left corner of 1632the cropping region measured downward and rightward with respect to the upper 1633left corner of the image. If the <a href="command-line-options.html#gravity">-gravity</a> option is 1634present with <code>NorthEast</code>, <code>East</code>, or <code>SouthEast</code> 1635gravity, it gives the distance leftward from the right edge of the image to 1636the right edge of the cropping region. Similarly, if the <a 1637href="command-line-options.html#gravity">-gravity</a> option is present with <code>SouthWest</code>, 1638<code>South</code>, or <code>SouthEast</code> gravity, the distance is measured 1639upward between the bottom edges.</p> 1640 1641<p>If the <var>x</var> and <var>y</var> offsets are 1642omitted, a set of tiles of the specified geometry, covering the entire input 1643image, is generated. The rightmost tiles and the bottom tiles are smaller if 1644the specified geometry extends beyond the dimensions of the input image.</p> 1645 1646<p>You can add the <var>@</var> to the geometry argument to equally divide the image into the number of tiles generated.</p> 1647 1648<p>By adding a exclamation character flag to the geometry argument, the 1649cropped images virtual canvas page size and offset is set as if the 1650geometry argument was a viewport or window. This means the canvas page size 1651is set to exactly the same size you specified, the image offset set 1652relative top left corner of the region cropped. </p> 1653 1654<p>If the cropped image 'missed' the actual image on its virtual canvas, a 1655special single pixel transparent 'missed' image is returned, and a 'crop 1656missed' warning given. </p> 1657 1658<p>It might be necessary to <a href="command-line-options.html#repage" >+repage</a> the image prior to 1659cropping the image to ensure the crop coordinate frame is relocated to the 1660upper-left corner of the visible image. 1661 1662Similarly you may want to use <a href="command-line-options.html#repage" >+repage</a> after cropping to 1663remove the page offset that will be left behind. This is especially true when 1664you are going to write to an image format such as PNG that supports an image 1665offset.</p> 1666 1667<div style="margin: auto;"> 1668 <h3 class="magick-header"><a id="cycle"></a>-cycle <var>amount</var></h3> 1669</div> 1670 1671<p class="magick-description">displace image colormap by amount.</p> 1672 1673<p><var>Amount</var> defines the number of positions each 1674colormap entry is shifted.</p> 1675 1676 1677<div style="margin: auto;"> 1678 <h3 class="magick-header"><a id="debug"></a>-debug <var>events</var></h3> 1679</div> 1680 1681<p class="magick-description">enable debug printout.</p> 1682 1683<p>The <code>events</code> parameter specifies which events are to be logged. It 1684can be either <code>None</code>, <code>All</code>, <code>Trace</code>, or 1685a comma-separated list consisting of one or more of the following domains: 1686<code>Accelerate</code>, <code>Annotate</code>, <code>Blob</code>, <code>Cache</code>, 1687<code>Coder</code>, <code>Configure</code>, <code>Deprecate</code>, 1688<code>Exception</code>, <code>Locale</code>, <code>Render</code>, 1689<code>Resource</code>, <code>Security</code>, <code>TemporaryFile</code>, 1690<code>Transform</code>, <code>X11</code>, or <code>User</code>. </p> 1691 1692 1693<p>For example, to log cache and blob events, use.</p> 1694 1695<pre> 1696convert -debug "Cache,Blob" rose: rose.png 1697</pre> 1698 1699<p>The <code>User</code> domain is normally empty, but developers can log user 1700events in their private copy of ImageMagick.</p> 1701 1702<p>To print the complete list of debug methods, use <a href="command-line-options.html#list">-list 1703debug</a>.</p> 1704 1705<p>Use the <a href="command-line-options.html#log">-log</a> option to specify the format for debugging 1706output.</p> 1707 1708<p>Use <a href="command-line-options.html#debug">+debug</a> to turn off all logging.</p> 1709 1710<p>Debugging may also be set using the <code>MAGICK_DEBUG</code> <a href="resources.html#environment" 1711>environment variable</a>. The allowed values for the <code>MAGICK_DEBUG</code> 1712environment variable are the same as for the <a href="command-line-options.html#debug">-debug</a> 1713option.</p> 1714 1715 1716<div style="margin: auto;"> 1717 <h3 class="magick-header"><a id="decipher"></a>-decipher <var>filename</var></h3> 1718</div> 1719 1720<p class="magick-description">Decipher and restore pixels that were previously transformed by <a href="command-line-options.html#encipher">-encipher</a>.</p> 1721 1722<p>Get the passphrase from the file specified by <var>filename</var>.</p> 1723 1724<p>For more information, see the webpage, <a 1725href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or 1726Decipher an Image</a>.</p> 1727 1728 1729<div style="margin: auto;"> 1730 <h3 class="magick-header"><a id="deconstruct"></a>-deconstruct</h3> 1731</div> 1732 1733<p class="magick-description">find areas that has changed between images </p> 1734 1735<p>Given a sequence of images all the same size, such as produced by <a 1736href="command-line-options.html#coalesce">-coalesce</a>, replace the second and later images, with 1737a smaller image of just the area that changed relative to the previous image. 1738</p> 1739 1740<p>The resulting sequence of images can be used to optimize an animation 1741sequence, though will not work correctly for GIF animations when parts of the 1742animation can go from opaque to transparent. </p> 1743 1744<p>This option is actually equivalent to the <a href="command-line-options.html#layers">-layers</a> 1745method '<code>compare-any</code>'. </p> 1746 1747 1748<div style="margin: auto;"> 1749 <h3 class="magick-header"><a id="define"></a>-define <var>key</var>{<var>=value</var>}<var>...</var></h3> 1750</div> 1751 1752<p class="magick-description">add specific global settings generally used to control coders and image processing operations.</p> 1753 1754<p>This option creates one or more definitions for coders and decoders to use 1755while reading and writing image data. Definitions are generally used to 1756control image file format coder modules, and image processing operations, 1757beyond what is provided by normal means. Defined settings are listed in <a 1758href="command-line-options.html#verbose" >-verbose</a> information ("<code>info:</code>" output format) 1759as "Artifacts". </p> 1760 1761<p>If <var>value</var> is missing for a definition, an empty-valued 1762definition of a flag is created with that name. This used to control on/off 1763options. Use <a href="command-line-options.html#define">+define key</a> to remove definitions 1764previously created. Use <a href="command-line-options.html#define">+define "*"</a> to remove all 1765existing definitions.</p> 1766 1767<p>The same 'artifact' settings can also be defined using the <a 1768href="command-line-options.html#set" >-set "option:<var>key</var>" "<var>value</var>"</a> option, which also allows the use of <a href="escape.html" >Format and Print Image 1769Properties</a> in the defined value. </p> 1770 1771<p>The <var>option</var> and <var>key</var> are case-independent (they are 1772converted to lowercase for use within the decoders) while the <var>value</var> 1773is case-dependent.</p> 1774 1775<p>Such settings are global in scope, and affect all images and operations. </p> 1776 1777<p>The following definitions are just some of the artifacts that are 1778available:</p> 1779 1780<table class="table table-condensed table-striped"> 1781 <tr> 1782 <td>bmp:format=<var>value</var></td> 1783 <td> valid values are <var>bmp2</var>, <var>bmp3</var>, 1784 and <var>bmp4</var>. This option can be useful when the 1785 method of prepending "BMP2:" to the output filename is inconvenient or 1786 is not available, such as when using the <a href="mogrify.html">mogrify</a> utility.</td> 1787 </tr> 1788 1789 <tr> 1790 <td>colorspace:auto-grayscale=<var>on|off</var></td> 1791 <td>prevent automatic conversion to grayscale inside coders that support 1792 grayscale. This should be accompanied by -type truecolor. PNG and TIF do 1793 not need this define. With PNG, just use PNG24:image. With TIF, just use 1794 -type truecolor. JPG and PSD will need this define.</td> 1795 </tr> 1796 1797 <tr> 1798 <td>complex:snr=<var>value</var></td> 1799 <td>Set the divide SNR constant<a href="command-line-options.html#complex">-complex</a></td> 1800 </tr> 1801 1802 <tr> 1803 <td>compose:args=<var>arguments</var></td> 1804 <td>Sets certain compose argument values when using convert ... -compose ... 1805 -composite. See <a href="compose.html" 1806 >Image Composition</a></td> 1807 </tr> 1808 1809 <tr> 1810 <td>compose:clamp=<var>on|off</var></td> 1811 <td>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. Define supported in ImageMagick 6.9.1-3 and above.</td> 1812 </tr> 1813 1814 <tr> 1815 <td>connected-components:area-threshold=<var>value</var></td> 1816 <td>Merges any region with area smaller than <var>value</var> into its surrounding region or largest neighbor.</td> 1817 </tr> 1818 1819 <tr> 1820 <td>connected-components:keep=<var>list-of-ids</var></td> 1821 <td>Command and/or hyphenated list of id values to keep in the output. Supported in Imagemagick 6.9.3-0.</td> 1822 </tr> 1823 1824 <tr> 1825 <td>connected-components:mean-color=<var>true</var></td> 1826 <td>Changes the output image from id values to mean color values. Supported in Imagemagick 6.9.2-8.</td> 1827 </tr> 1828 1829 <tr> 1830 <td>connected-components:remove=<var>list-of-ids</var></td> 1831 <td>Command and/or hyphenated list of id values to remove from the output. Supported in Imagemagick 6.9.2-9.</td> 1832 </tr> 1833 1834 <tr> 1835 <td>connected-components:verbose=<var>true</var></td> 1836 <td>Lists id, bounding box, centroid, area, mean color for each region.</td> 1837 </tr> 1838 1839 <tr> 1840 <td>convolve:scale=<var>{kernel_scale}[!^] [,{origin_addition}] [%]</var></td> 1841 <td>Defines the kernel scaling. The special flag ! automatically scales to 1842 full dynamic range. The ! flag can be used in combination with a factor or 1843 percent. The factor or percent is then applied after the automatic scaling. 1844 An example is 50%!. This produces a result 50% darker than full dynamic 1845 range scaling. The ^ flag assures the kernel is 'zero-summing', for 1846 example when some values are positive and some are negative as in edge 1847 detection kernels. The origin addition adds that value to the center 1848 pixel of the kernel. This produces and effect that is like adding the image 1849 that many times to the result of the filtered image. The typical value 1850 is 1 so that the original image is added to the result of the convolution. 1851 The default is 0.</td> 1852 </tr> 1853 1854 <tr> 1855 <td>convolve:showkernel=<var>1</var></td> 1856 <td>Outputs (to 'standard error') all the information about a specified <a 1857 href="command-line-options.html#morphology" >-morphology convolve</a> kernel.</td> 1858 </tr> 1859 1860 <tr> 1861 <td>dcm:display-range=<var>reset</var></td> 1862 <td>Sets the display range to the minimum and maximum pixel values for the 1863 DCM image format.</td> 1864 </tr> 1865 1866 <tr> 1867 <td>dds:cluster-fit=<var>true|false</var></td> 1868 <td>Enables the dds cluster-fit.</td> 1869 </tr> 1870 1871 <tr> 1872 <td>dds:compression=<var>dxt1|dxt5|none</var></td> 1873 <td>Sets the dds compression.</td> 1874 </tr> 1875 1876 <tr> 1877 <td>dds:mipmaps=<var>value</var></td> 1878 <td>Sets the dds number of mipmaps.</td> 1879 </tr> 1880 1881 <tr> 1882 <td>dds:weight-by-alpha=<var>true|false</var></td> 1883 <td>Enables the dds alpha weighting.</td> 1884 </tr> 1885 1886 <tr> 1887 <td>delegate:bimodal=<var>true</var></td> 1888 <td>Specifies direct conversion from Postscript to PDF.</td> 1889 </tr> 1890 1891 <tr> 1892 <td>distort:scale=<var>value</var></td> 1893 <td>Sets the output scaling factor for use with <a href="command-line-options.html#distort" 1894 >-distort</a></td> 1895 </tr> 1896 1897 <tr> 1898 <td>distort:viewport=<var>WxH+X+Y</var></td> 1899 <td>Sets the viewport for use with <a href="command-line-options.html#distort">-distort</a></td> 1900 </tr> 1901 1902 <tr> 1903 <td>dot:layout-engine=<var>value</var></td> 1904 <td>Specifies the layout engine for the DOT image format (e.g. 1905 <code>neato</code>).</td> 1906 </tr> 1907 1908 <tr> 1909 <td>filter:option=<var>value</var></td> 1910 <td>Set a filter option for use with <a href="command-line-options.html#resize">-resize</a>. 1911 See <a href="command-line-options.html#filter">-filter</a> for details.</td> 1912 </tr> 1913 1914 <tr> 1915 <td>fourier:normalize=<var>inverse</var></td> 1916 <td>Sets the location for the FFT/IFT normalization as use by 1917 <a href="command-line-options.html#fft">+-fft</a> and <a href="command-line-options.html#ift">+-ift</a>. The default is 1918 <var>forward</var>.</td> 1919 </tr> 1920 1921 <tr> 1922 <td>h:format=<var>value</var></td> 1923 <td>Set the image encoding format use when writing a C-style header. 1924 <var>format</var> can be any output format supported by ImageMagick 1925 except for <var>h</var> and <var>magick</var></td>. If this 1926 option is omitted, the default is <var>GIF</var> for PseudoClass 1927 images and <var>PNM</var> for DirectClass images. 1928 </tr> 1929 1930 <tr> 1931 <td>icon:auto-resize</td> 1932 <td>Automatically stores multiple sizes when writing an ico image 1933 (requires a 256x256 input image).</td> 1934 </tr> 1935 1936 <tr> 1937 <td>jp2:layer-number=<var>value</var></td> 1938 <td>Sets the maximum number of quality layers to decode. Same for JPT, JC2, 1939 and J2K</td> 1940 </tr> 1941 1942 <tr> 1943 <td>jp2:number-resolutions=<var>value</var></td> 1944 <td>Sets the number of resolutions to encode.Same for JPT, JC2, and J2K</td> 1945 </tr> 1946 1947 <tr> 1948 <td>jp2:progression-order=<var>value</var></td> 1949 <td>choose from LRCP, RLCP, RPCL, PCRL or CPRL. Same for JPT, JC2, and 1950 J2K</td> 1951 </tr> 1952 1953 <tr> 1954 <td>jp2:quality=<var>value,value...</var></td> 1955 <td>Sets the quality layer PSNR, given in dB. The order is from left to 1956 right in ascending order. The default is a single lossless quality layer. 1957 Same for JPT, JC2, and J2K</td> 1958 </tr> 1959 1960 <tr> 1961 <td>jp2:rate=<var>value</var></td> 1962 <td>Specify the compression factor to use while writing JPEG-2000 files. The 1963 compression factor is the reciprocal of the compression ratio. The valid 1964 range is 0.0 to 1.0, with 1.0 indicating lossless compression. If defined, 1965 this value overrides the -quality setting. A quality setting of 75 1966 results in a rate value of 0.06641. Same for JPT, JC2, and J2K</td> 1967 </tr> 1968 1969 <tr> 1970 <td>jp2:reduce-factor=<var>value</var></td> 1971 <td>Sets the number of highest resolution levels to be discarded.Same for 1972 JPT, JC2, and J2K</td> 1973 </tr> 1974 1975 <tr> 1976 <td>jpeg:block-smoothing=<var>on|off</var></td> 1977 <td> </td> 1978 </tr> 1979 1980 <tr> 1981 <td>jpeg:colors=<var>value</var></td> 1982 <td>Set the desired number of colors and let the JPEG encoder do the 1983 quantizing.</td> 1984 </tr> 1985 1986 <tr> 1987 <td>jpeg:dct-method=<var>value</var></td> 1988 <td>Choose from <code>default</code>, <code>fastest</code>, 1989 <code>float</code>, <code>ifast</code>, and <code>islow</code>.</td> 1990 </tr> 1991 1992 <tr> 1993 <td>jpeg:extent=<var>value</var></td> 1994 <td>Restrict the maximum JPEG file size, for example <code>-define 1995 jpeg:extent=400KB</code>. The JPEG encoder will search for the highest 1996 compression quality level that results in an output file that does not 1997 exceed the value. The <code>-quality</code> option also will be respected 1998 starting with version 6.9.2-5. Between 6.9.1-0 and 6.9.2-4, add -quality 1999 100 in order for the jpeg:extent to work properly. Prior to 6.9.1-0, the 2000 -quality setting was ignored.</td> 2001 </tr> 2002 2003 <tr> 2004 <td>jpeg:fancy-upsampling=<var>on|off</var></td> 2005 <td> </td> 2006 </tr> 2007 2008 <tr> 2009 <td>jpeg:optimize-coding=<var>on|off</var></td> 2010 <td> </td> 2011 </tr> 2012 2013 <tr> 2014 <td>jpeg:q-table=<var>table</var></td> 2015 <td> </td> 2016 </tr> 2017 2018 <tr> 2019 <td>jpeg:sampling-factor=<var>sampling-factor-string</var></td> 2020 <td> </td> 2021 </tr> 2022 2023 <tr> 2024 <td>jpeg:size=<var>geometry</var></td> 2025 <td>Set the size hint of a JPEG image, for 2026 example, <code>-define jpeg:size=128x128</code>. 2027 It is most useful for increasing performance and reducing the memory 2028 requirements when reducing the size of a large JPEG image.</td> 2029 </tr> 2030 2031 <tr> 2032 <td>json:features</td> 2033 <td>includes features in verbose information</td> 2034 </tr> 2035 2036 <tr> 2037 <td>json:limit</td> 2038 <td> </td> 2039 </tr> 2040 2041 <tr> 2042 <td>json:locate</td> 2043 <td> </td> 2044 </tr> 2045 2046 <tr> 2047 <td>json:moments</td> 2048 <td>includes image moments in verbose information</td> 2049 </tr> 2050 2051 <tr> 2052 <td>magick:format=<var>value</var></td> 2053 <td>Set the image encoding format use when writing a C-style header. 2054 This is the same as "h:format=format" described above.</td>. 2055 </tr> 2056 2057 <tr> 2058 <td>mng:need-cacheoff</td> 2059 <td>turn playback caching off for streaming MNG.</td> 2060 </tr> 2061 2062 <tr> 2063 <td>morphology:compose=<var>compose-method</var></td> 2064 <td>Specifies how to merge results generated by multiple<a 2065 href="command-line-options.html#morphology" >-morphology</a> kernel. The default is none. One 2066 typical value is 'lighten' as used, for example, with the sobel edge 2067 kernels. </td> 2068 </tr> 2069 2070 <tr> 2071 <td>morphology:showkernel=<var>1</var></td> 2072 <td>Outputs (to 'standard error') all the information about a generated <a 2073 href="command-line-options.html#morphology" >-morphology</a> kernel.</td> 2074 </tr> 2075 2076 <tr> 2077 <td>pcl:fit-to-page=<var>true</var></td> 2078 2079 <tr> 2080 <td>pdf:fit-page=<var>geometry</var></td> 2081 <td> geometry specifies the scaling dimensions for resizing when the PDF is 2082 being read. The geometry is either WxH{%} or page size. No offsets are 2083 allowed. (introduced in IM 6.8.8-8)</td> 2084 </tr> 2085 2086 <tr> 2087 <td>pdf:fit-to-page=<var>true</var></td> 2088 <td> </td> 2089 </tr> 2090 2091 <tr> 2092 <td>pdf:use-cropbox=<var>true</var></td> 2093 <td> </td> 2094 </tr> 2095 2096 <tr> 2097 <td>pdf:use-trimbox=<var>true</var></td> 2098 <td> </td> 2099 </tr> 2100 2101 <tr> 2102 <td>png:bit-depth=<var>value</var></td> 2103 <td> </td> 2104 </tr> 2105 <tr> 2106 <td>png:color-type=<var>value</var></td> 2107 <td>desired bit-depth and color-type for PNG output. You can force the PNG 2108 encoder to use a different bit-depth and color-type than it would have 2109 normally selected, but only if this does not cause any loss of image 2110 quality. Any attempt to reduce image quality is treated as an error and no 2111 PNG file is written. E.g., if you have a 1-bit black-and-white image, you 2112 can use these "defines" to cause it to be written as an 8-bit grayscale, 2113 indexed, or even a 64-bit RGBA. But if you have a 16-million color image, 2114 you cannot force it to be written as a grayscale or indexed PNG. If you 2115 wish to do this, you must use the appropriate <a href="command-line-options.html#depth">-depth</a>, 2116 <a href="command-line-options.html#colors">-colors</a>, or <a href="command-line-options.html#type">-type</a> directives to 2117 reduce the image quality prior to using the PNG encoder. Note that in 2118 indexed PNG files, "bit-depth" refers to the number of bits per index, 2119 which can be 1, 2, 4, or 8. In such files, the color samples always have 2120 8-bit depth.</td> 2121 </tr> 2122 2123 <tr> 2124 <td>png:compression-filter=<var>value</var></td> 2125 <td> valid values are 0 through 9. 0-4 are the corresponding PNG filters, 2126 5 means adaptive filtering except for images with a colormap, 6 means 2127 adaptive filtering for all images, 7 means MNG "loco" compression, 8 means 2128 Z_RLE strategy with adaptive filtering, and 9 means Z_RLE strategy with no 2129 filtering.</td> 2130 </tr> 2131 2132 <tr> 2133 <td>png:compression-level=<var>value</var></td> 2134 <td> valid values are 0 through 9, with 0 providing the least but fastest 2135 compression and 9 usually providing the best and always the slowest.</td> 2136 </tr> 2137 2138 <tr> 2139 <td>png:compression-strategy=<var>value</var></td> 2140 <td> valid values are 0 through 4, meaning default, filtered, huffman_only, 2141 rle, and fixed ZLIB compression strategy. If you are using an old zlib 2142 that does not support Z_RLE (before 1.2.0) or Z_FIXED (before 1.2.2.2), 2143 values 3 and 4, respectively, will use the zlib default strategy 2144 instead.</td> 2145 </tr> 2146 2147 <tr> 2148 <td>png:format=<var>value</var></td> 2149 <td> valid values are <var>png8</var>, <var>png24</var>, 2150 <var>png32</var>, <var>png48</var>, 2151 <var>png64</var>, and <var>png00</var>. 2152 This property can be useful for specifying 2153 the specific PNG format to be used, when the usual method of prepending the 2154 format name to the output filename is inconvenient, such as when writing 2155 a PNG-encoded ICO file or when using <a href="mogrify.html">mogrify</a>. 2156 Value = <var>png8</var> reduces the number of colors to 256, 2157 only one of which may be fully transparent, if necessary. The other 2158 values do not force any reduction of quality; it is an error to request 2159 a format that cannot represent the image data without loss (except that 2160 it is allowed to reduce the bit-depth from 16 to 8 for all formats). 2161 Value = <var>png24</var> and <var>png48</var> 2162 allow transparency, only if a single color is fully transparent and that 2163 color does not also appear in an opaque pixel; such transparency is 2164 written in a PNG <code>tRNS</code> chunk. 2165 Value = <var>png00</var> causes the image to inherit its 2166 color-type and bit-depth from the input image, if the input was also 2167 a PNG.</td> 2168 </tr> 2169 2170 <tr> 2171 <td>png:exclude-chunk=<var>value</var></td> 2172 2173 <tr> 2174 <td>png:include-chunk=<var>value</var></td> 2175 <td>ancillary chunks to be excluded from or included in PNG output. 2176 2177 <p>The <var>value</var> can be the name of a PNG chunk-type such 2178 as <var>bKGD</var>, a comma-separated list of chunk-names 2179 (which can include the word <var>date</var>, the word 2180 <var>all</var>, or the word <var>none</var>). 2181 Although PNG chunk-names are case-dependent, you can use all lowercase 2182 names if you prefer.</p> 2183 2184 <p>The "include-chunk" and "exclude-chunk" lists only affect the behavior 2185 of the PNG encoder and have no effect on the PNG decoder.</p> 2186 2187 <p>As a special case, if the <code>sRGB</code> chunk is excluded and 2188 the <code>gAMA</code> chunk is included, the <code>gAMA</code> chunk will 2189 only be written if gamma is not 1/2.2, since most decoders assume 2190 sRGB and gamma=1/2.2 when no colorspace information is included in 2191 the PNG file. Because the list is processed from left to right, you 2192 can achieve this with a single define:</p> 2193 2194<pre> 2195-define png:include-chunk=none,gAMA 2196</pre> 2197 2198 <p>As a special case, if the <code>sRGB</code> chunk is not excluded and 2199 the PNG encoder recognizes that the image contains the sRGB ICC profile, 2200 the PNG encoder will write the <code>sRGB</code> chunk instead of the 2201 entire ICC profile. To force the PNG encoder to write the sRGB 2202 profile as an <code>iCCP</code> chunk in the output PNG instead of the 2203 <code>sRGB</code> chunk, exclude the <code>sRGB</code> chunk.</p> 2204 2205 <p>The critical PNG chunks <code>IHDR</code>, <code>PLTE</code>, 2206 <code>IDAT</code>, and <code>IEND</code> cannot be excluded. Any such 2207 entries appearing in the list will be ignored.</p> 2208 2209 <p>If the ancillary PNG <code>tRNS</code> chunk is excluded and the 2210 image has transparency, the PNG colortype is forced to be 4 or 6 2211 (GRAY_ALPHA or RGBA). If the image is not transparent, then the 2212 <code>tRNS</code> chunk isn't written anyhow, and there is no effect 2213 on the PNG colortype of the output image.</p> 2214 2215 <p>The <a href="command-line-options.html#strip">-strip</a> option does the equivalent of the 2216 following for PNG output:</p> 2217 2218<pre> 2219-define png:exclude-chunk=EXIF,iCCP,iTXt,sRGB,tEXt,zCCP,zTXt,date 2220</pre> 2221 2222 <p>The default behavior is to include all known PNG ancillary chunks 2223 plus ImageMagick's private <code>vpAg</code> ("virtual page") chunk, 2224 and to exclude all PNG chunks that are unknown to ImageMagick, 2225 regardless of their PNG "copy-safe" status as described in the 2226 PNG specification.</p> 2227 2228 <p>Any chunk names that are not known to ImageMagick are ignored 2229 if they appear in either the "include-chunk" or "exclude-chunk" list. 2230 The ancillary chunks currently known to ImageMagick are 2231 <code>bKGD</code>, <code>cHRM</code>, <code>gAMA</code>, <code>iCCP</code>, 2232 <code>oFFs</code>, <code>pHYs</code>, <code>sRGB</code>, <code>tEXt</code>, 2233 <code>tRNS</code>, <code>vpAg</code>, and <code>zTXt</code>.</p> 2234 2235 <p>You can also put <code>date</code> in the list to include or exclude 2236 the "Date:create" and "Date:modify" text chunks that ImageMagick normally 2237 inserts in the output PNG.</p></td> 2238 </tr> 2239 2240 <tr> 2241 <td>png:preserve-colormap[=<var>true</var>]</td> 2242 <td>Use the existing image->colormap. Normally the PNG encoder will 2243 try to optimize the palette, eliminating unused entries and putting 2244 the transparent colors first. If this flag is set, that behavior 2245 is suppressed.</td> 2246 </tr> 2247 2248 <tr> 2249 <td>png:preserve-iCCP[=<var>true</var>]</td> 2250 <td>By default, the PNG decoder and encoder examine any ICC profile 2251 that is present, either from an <code>iCCP</code> chunk in the PNG 2252 input or supplied via an option, and if the profile is recognized 2253 to be the sRGB profile, converts it to the <code>sRGB</code> chunk. 2254 You can use <code>-define png:preserve-iCCP</code> to prevent 2255 this from happening; in such cases the <code>iCCP</code> chunk 2256 will be read or written and no <code>sRGB</code> chunk will be 2257 written. There are some ICC profiles that claim to be sRGB but 2258 have various errors that cause them to be rejected by libpng16; such 2259 profiles are recognized anyhow and converted to the <code>sRGB</code> 2260 chunk, but are rejected if the <code>-define png:preserve-iCCP</code> 2261 is present. Note that not all "sRGB" ICC profiles are recognized 2262 yet; we will add them to the list as we encounter them.</td> 2263 </tr> 2264 2265 <tr> 2266 <td>png:swap-bytes[=<var>true</var>]</td> 2267 <td>The PNG specification requires that any multi-byte integers be stored in 2268 network byte order (MSB-LSB endian). This option allows you to 2269 fix any invalid PNG files that have 16-bit samples stored incorrectly 2270 in little-endian order (LSB-MSB). The "-define png:swap-bytes" option 2271 must appear before the input filename on the commandline. The swapping 2272 is done during the libpng decoding operation.</td> 2273 </tr> 2274 2275 <tr> 2276 <td>profile:skip=<var>name1,name2,...</var></td> 2277 <td>Skip the named profile[s] when reading the image. Use skip="*" to 2278 skip all named profiles in the image. Many named profiles exist, 2279 including ICC, EXIF, APP1, IPTC, XMP, and others.</td> 2280 </tr> 2281 2282 <tr> 2283 <td>ps:imagemask</td> 2284 <td>If the ps:imagemask flag is defined, the PS3 and EPS3 coders will 2285 create Postscript files that render bilevel images with the Postscript 2286 imagemask operator instead of the image operator.</td> 2287 </tr> 2288 2289 <tr> 2290 <td>psd:alpha-unblend=off</td> 2291 <td>Disables new automatic un-blending of transparency with the base image 2292 for the flattened layer 0 before adding the alpha channel to the output 2293 image. This define must be placed before the input psd image. (Available 2294 as of IM 6.9.2.5). The automatic un-blending is new to IM 6.9.2.5 and 2295 prevents the transparency from being applied twice in the output 2296 image.</td> 2297 </tr> 2298 2299 <tr> 2300 <td>preserve-timestamp=<var>{True, False}</var></td> 2301 <td>Preserve file timestamp (<code>mogrify</code> only).</td> 2302 </tr> 2303 2304 <tr> 2305 <td>quantum:format=<var>type</var></td> 2306 <td>Set the type to <code>floating-point</code> to specify a floating-point 2307 format for raw files (e.g. GRAY:) or for MIFF and TIFF images in HDRI mode 2308 to preserve negative values. If <a href="command-line-options.html#depth">-depth</a> 16 is 2309 included, the result is a single precision floating point format. 2310 If <a href="command-line-options.html#depth">-depth</a> 32 is included, the result is 2311 double precision floating point format.</td> 2312 </tr> 2313 2314 <tr> 2315 <td>quantum:polarity=<var>photometric-interpretation</var></td> 2316 <td>Set the photometric-interpretation of an image (typically for TIFF image 2317 file format) to either <code>min-is-black</code> (default) or 2318 <code>min-is-white</code>.</td> 2319 </tr> 2320 2321 <tr> 2322 <td>sample:offset=<var>geometry</var></td> 2323 <td>Location of the sampling point within the sub-region being sampled, 2324 expressed as percentages (see <a href="command-line-options.html#sample" >-sample</a>).</td> 2325 </tr> 2326 2327 <tr> 2328 <td>showkernel=<var>1</var></td> 2329 <td>Outputs (to 'standard error') all the information about a generated <a 2330 href="command-line-options.html#morphology" >-morphology</a> kernel.</td> 2331 </tr> 2332 2333 <tr> 2334 <td>stream:buffer-size=<var>value</var></td> 2335 <td>Set the stream buffer size. Select 0 for unbuffered I/O.</td> 2336 </tr> 2337 2338 <tr> 2339 <td>tiff:alpha=<var>associated|unassociated|unspecified</var></td> 2340 <td>Specify the alpha extra samples as associated, unassociated or unspecified </td> 2341 </tr> 2342 2343 <tr> 2344 <td>tiff:endian=<var>msb|lsb</var></td> 2345 <td> </td> 2346 </tr> 2347 2348 <tr> 2349 <td>tiff:exif-properties=<var>false</var></td> 2350 <td>Skips reading the EXIF properties.</td> 2351 </tr> 2352 2353 <tr> 2354 <td>tiff:fill-order=<var>msb|lsb</var></td> 2355 <td> </td> 2356 </tr> 2357 2358 <tr> 2359 <td>tiff:ignore-layers=<var>true</var></td> 2360 <td>Ignores the photoshop layers.</td> 2361 </tr> 2362 2363 <tr> 2364 <td>tiff:ignore-tags=<var>comma-separate-list-of-tag-IDs</var></td> 2365 <td>Allows one or more tag ID values to be ignored.</td> 2366 </tr> 2367 2368 <tr> 2369 <td>tiff:rows-per-strip=<var>value</var></td> 2370 <td>Sets the number of rows per strip</td> 2371 </tr> 2372 2373 <tr> 2374 <td>tiff:tile-geometry=<var>WxH</var></td> 2375 <td>Sets the tile size for pyramid tiffs. Requires the suffix 2376 PTIF: before the outputname</td> 2377 </tr> 2378 2379 <tr> 2380 <td>type:features=<var>string</var></td> 2381 <td> </td> 2382 </tr> 2383 2384 <tr> 2385 <td>type:hinting=<var>off</var></td> 2386 <td> </td> 2387 </tr> 2388</table> 2389 2390<p>For example, to create a postscript file that will render only the black 2391pixels of a bilevel image, use:</p> 2392 2393<pre> 2394convert bilevel.tif -define ps:imagemask eps3:stencil.ps 2395</pre> 2396 2397<p>Set attributes of the image registry by prefixing the value with 2398<code>registry:</code>. For example, to set a temporary path to put work files, 2399use:</p> 2400 2401<pre> 2402-define registry:temporary-path=/data/tmp 2403</pre> 2404 2405<div style="margin: auto;"> 2406 <h3 class="magick-header"><a id="delay"></a>-delay <var>ticks</var> <br />-delay <var>ticks</var>x<var>ticks-per-second</var> {<var><</var>} {<var>></var>}</h3> 2407</div> 2408 2409<p class="magick-description">display the next image after pausing.</p> 2410 2411<p>This option is useful for regulating the animation of image sequences 2412<var>ticks/ticks-per-second</var> seconds must expire before the display of the 2413next image. The default is no delay between each showing of the image 2414sequence. The default ticks-per-second is 100.</p> 2415 2416<p>Use <code>></code> to change the image delay <var>only</var> if its current 2417value exceeds the given delay. <code><</code> changes the image delay 2418<var>only</var> if current value is less than the given delay. For example, if 2419you specify <code>30></code> and the image delay is 20, the image delay does 2420not change. However, if the image delay is 40 or 50, the delay it is changed 2421to 30. Enclose the given delay in quotation marks to prevent the 2422<code><</code> or <code>></code> from being interpreted by your shell as 2423a file redirection.</p> 2424 2425 2426<div style="margin: auto;"> 2427 <h3 class="magick-header"><a id="delete"></a>-delete <var>indexes</var></h3> 2428</div> 2429 2430<p class="magick-description">delete the images specified by index, from the image sequence.</p> 2431 2432<p>Specify the image by its index in the sequence. The first image is index 24330. Negative indexes are relative to the end of the sequence, for example, -1 2434represents the last image of the sequence. Specify a range of images with 2435a dash (e.g. 0-4). Separate indexes with a comma (e.g. 0,2). Use 2436<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> 2437 2438 2439<div style="margin: auto;"> 2440 <h3 class="magick-header"><a id="density"></a>-density <var>width</var><br />-density <var>width</var>x<var>height</var></h3> 2441</div> 2442 2443<p class="magick-description">Set the horizontal and vertical resolution of an image for rendering to devices.</p> 2444 2445<p>This option specifies the image resolution to store while encoding a raster 2446image or the canvas resolution while rendering (reading) vector formats such 2447as Postscript, PDF, WMF, and SVG into a raster image. Image resolution 2448provides the unit of measure to apply when rendering to an output device or 2449raster image. The default unit of measure is in dots per inch (DPI). The <a 2450href="command-line-options.html#units">-units</a> option may be used to select dots per centimeter 2451instead.</p> 2452 2453<p>The default resolution is 72 dots per inch, which is equivalent to one 2454point per pixel (Macintosh and Postscript standard). Computer screens are 2455normally 72 or 96 dots per inch, while printers typically support 150, 300, 2456600, or 1200 dots per inch. To determine the resolution of your display, use 2457a ruler to measure the width of your screen in inches, and divide by the 2458number of horizontal pixels (1024 on a 1024x768 display).</p> 2459 2460<p>If the file format supports it, this option may be used to update the 2461stored image resolution. Note that Photoshop stores and obtains image 2462resolution from a proprietary embedded profile. If this profile is not 2463stripped from the image, then Photoshop will continue to treat the image using 2464its former resolution, ignoring the image resolution specified in the standard 2465file header.</p> 2466 2467<p>The <a href="command-line-options.html#density">-density</a> option sets an <var>attribute</var> and 2468does not alter the underlying raster image. It may be used to adjust the 2469rendered size for desktop publishing purposes by adjusting the scale applied 2470to the pixels. To resize the image so that it is the same size at a different 2471resolution, use the <a href="command-line-options.html#resample">-resample</a> option.</p> 2472 2473<div style="margin: auto;"> 2474 <h3 class="magick-header"><a id="depth"></a>-depth <var>value</var></h3> 2475</div> 2476 2477<p class="magick-description">depth of the image.</p> 2478 2479<p>This the number of bits in a color sample within a pixel. Use this option 2480to specify the depth of raw images whose depth is unknown such as GRAY, RGB, 2481or CMYK, or to change the depth of any image after it has been read.</p> 2482 2483<div style="margin: auto;"> 2484 <h3 class="magick-header"><a id="descend"></a>-descend</h3> 2485</div> 2486 2487<p class="magick-description">obtain image by descending window hierarchy.</p> 2488 2489<div style="margin: auto;"> 2490 <h3 class="magick-header"><a id="deskew"></a>-deskew <var>threshold{%}</var></h3> 2491</div> 2492 2493<p class="magick-description">straighten an image. A threshold of 40% works for most images.</p> 2494 2495<p>Use <a href="command-line-options.html#set">-set</a> <code>option:deskew:auto-crop 2496<var>width</var></code> to auto crop the image. The set argument is the pixel 2497width of the image background (e.g 40).</p> 2498 2499<div style="margin: auto;"> 2500 <h3 class="magick-header"><a id="despeckle"></a>-despeckle</h3> 2501</div> 2502 2503<p class="magick-description">reduce the speckles within an image.</p> 2504 2505<div style="margin: auto;"> 2506 <h3 class="magick-header"><a id="direction"></a>-direction <var>type</var></h3> 2507</div> 2508 2509<p class="magick-description">render text right-to-left or left-to-right.</p> 2510 2511<div style="margin: auto;"> 2512 <h3 class="magick-header"><a id="displace"></a>-displace <var>horizontal-scale</var>{%}{!}<br />-displace <var>horizontal-scale</var>x<var>vertical-scale</var>{%}{!}</h3> 2513</div> 2514 2515<p class="magick-description">shift image pixels as defined by a displacement map.</p> 2516 2517<p>With this option, the 'overlay' image, and optionally the 'mask' image, 2518is used as a displacement map, which is used to displace the lookup of 2519what part of the 'background' image is seen at each point of the overlaid 2520area. Much like the displacement map is a 'lens' that redirects light shining 2521through it so as to present a distorted view the original 'background' image 2522behind it. </p> 2523 2524<p>Any perfect grey areas of the displacement map produce a zero 2525displacement of the image. Black areas produce the given maximum negative 2526displacement of the lookup point, while white produce a maximum positive 2527displacement of the lookup. </p> 2528 2529<p>Note that it is the lookup of the 'background' that is displaced, not a 2530displacement of the image itself. As such an area of the displacement map 2531containing 'white' will have the lookup point 'shifted' by a positive amount, 2532and thus generating a copy of the destination image to the right/downward from 2533the correct position. That is the image will look like it may have been 2534'shifted' in a negative left/upward direction. Understanding this is a very 2535important in understanding how displacement maps work. </p> 2536 2537<p>The given arguments define the maximum amount of displacement in pixels 2538that a particular map can produce. If the displacement scale is large enough 2539it is also possible to lookup parts of the 'background' image that lie well 2540outside the bounds of the displacement map itself. That is you could very 2541easily copy a section of the original image from outside the overlay area 2542into the overlay area. </p> 2543 2544<p>The '%' flag makes the displacement scale relative to the size of the 2545overlay image (100% = half width/height of image). Using '!' switches 2546percentage arguments to refer to the destination image size instead. 2547these flags were added as of IM v6.5.3-5.</p> 2548 2549<p>Normally a single grayscale displacement map is provided, which with the 2550given scaling values will determine a single direction (vector) in which 2551displacements can occur (positively or negatively). However, if you also 2552specify a third image which is normally used as a <var>mask</var>, 2553the <var>composite image</var> is used for horizontal X 2554displacement, while the <var>mask image</var> is used for vertical Y 2555displacement. This allows you to define completely different displacement 2556values for the X and Y directions, and allowing you to lookup any point within 2557the <var>scale</var> bounds. In other words each pixel can lookup 2558any other nearby pixel, producing complex 2 dimensional displacements, rather 2559than a simple 1 dimensional vector displacements. </p> 2560 2561<p>Alternatively rather than supplying two separate images, as of IM v6.4.4-0, 2562you can use the 'red' channel of the overlay image to specify the horizontal 2563or X displacement, and the 'green' channel for the vertical or Y displacement. 2564</p> 2565 2566<p>As of IM v6.5.3-5 any alpha channel in the overlay image is used as a 2567mask the transparency of the destination image. However areas outside the 2568overlaid areas will not be effected. </p> 2569 2570 2571<div style="margin: auto;"> 2572 <h3 class="magick-header"><a id="display"></a>-display <var>host:display[.screen]</var></h3> 2573</div> 2574 2575<p class="magick-description">Specifies the X server to contact.</p> 2576 2577<p>This option is used with convert for obtaining image or font from this 2578X server. See <var>X(1)</var>.</p> 2579 2580<div style="margin: auto;"> 2581 <h3 class="magick-header"><a id="dispose"></a>-dispose <var>method</var></h3> 2582</div> 2583 2584<p class="magick-description">define the GIF disposal image setting for images that are being created or read in. </p> 2585 2586<p>The layer disposal method defines the way each the displayed image is to be 2587modified after the current 'frame' of an animation has finished being 2588displayed (after its 'delay' period), but before the next frame on an 2589animation is to be overlaid onto the display. </p> 2590 2591<p>Here are the valid methods:</p> 2592 2593<dl class="dl-horizontal"> 2594<dt>Undefined</dt><dd>0: No disposal specified (equivalent to '<code>none</code>').</dd> 2595<dt>None</dt><dd>1: Do not dispose, just overlay next frame image.</dd> 2596<dt>Background</dt><dd>2: Clear the frame area with the background color.</dd> 2597<dt>Previous</dt><dd>3: Clear to the image prior to this frames overlay.</dd> 2598</dl> 2599 2600<p>You can also use the numbers given above, which is what the GIF format 2601uses internally to represent the above settings. </p> 2602 2603<p>To print a complete list of dispose methods, use <a href="command-line-options.html#list">-list dispose</a>.</p> 2604 2605<p>Use <a href="command-line-options.html#dispose" >+dispose</a>, turn off the setting and prevent 2606resetting the layer disposal methods of images being read in. </p> 2607 2608<p>Use <a href="command-line-options.html#set">-set</a> '<code>dispose</code>' method to set the image 2609disposal method for images already in memory.</p> 2610 2611<div style="margin: auto;"> 2612 <h3 class="magick-header"><a id="dissimilarity-threshold"></a>-dissimilarity-threshold <var>value</var></h3> 2613</div> 2614 2615<p class="magick-description">maximum RMSE for subimage match (default 0.2).</p> 2616 2617 2618<div style="margin: auto;"> 2619 <h3 class="magick-header"><a id="dissolve"></a>-dissolve <var>src_percent</var>[x<var>dst_percent</var>]</h3> 2620</div> 2621 2622<p class="magick-description">dissolve an image into another by the given percent.</p> 2623 2624<p>The opacity of the composite image is multiplied by the given percent, then 2625it is composited 'over' the main image. If <var>src_percent</var> 2626is greater than 100, start dissolving the main image so it becomes 2627transparent at a value of '<code>200</code>'. If both percentages 2628are given, each image are dissolved to the percentages given. </p> 2629 2630<p>Note that dissolve percentages do not add, two opaque images dissolved 2631'50,50', produce a 75% transparency. For a 50% + 50% blending of the two 2632images, you would need to use dissolve values of '50,100'. </p> 2633 2634<div style="margin: auto;"> 2635 <h3 class="magick-header"><a id="distort"></a>-distort <var>method arguments</var></h3> 2636</div> 2637 2638<p class="magick-description">distort an image, using the given <var>method</var> and its required <var>arguments</var>.</p> 2639 2640<p>The <var>arguments</var> is a single string containing a list 2641of floating point numbers separated by commas or spaces. The number of 2642and meaning of the floating point values depends on the distortion <var>method</var> being used. </p> 2643 2644<p>Choose from these distortion types:</p> 2645 2646<table class="table table-condensed table-striped"> 2647 <tr> 2648 <th style="width: 8%">Method</th> 2649 <th>Description</th> 2650 </tr> 2651 2652 <tr> 2653 <td>ScaleRotateTranslate <br/> SRT</td> 2654 <td> 2655 Distort image by first scaling and rotating about a given 'center', 2656 before translating that 'center' to the new location, in that order. It 2657 is an alternative method of specifying a 'Affine' type of 2658 distortion, but without shearing effects. It also provides a good way 2659 of rotating and displacing a smaller image for tiling onto a larger 2660 background (IE 2-dimensional animations). <br/> 2661 2662 The number of arguments determine the specific meaning of each 2663 argument for the scales, rotation, and translation operations. <br/> 2664 2665 <dl class="dl-horizontal"> 2666 <dt>2:</dt><dd><var>Scale Angle</var></dd> 2667 <dt>3:</dt><dd><var>X,Y Angle</var></dd> 2668 <dt>4:</dt><dd><var>X,Y Scale Angle</var></dd> 2669 <dt>5:</dt> <dd><var>X,Y ScaleX,ScaleY Angle</var></dd> 2670 <dt>6:</dt> <dd><var>X,Y Scale Angle NewX,NewY</var></dd> 2671 <dt>7:</dt> <dd><var>X,Y ScaleX,ScaleY Angle NewX,NewY</var></dd> 2672 </dl> 2673 2674 This is actually an alternative way of specifying a 2 dimensional linear 2675 'Affine' or 'AffineProjection' distortion. </td> </tr> 2676 2677 <tr> 2678 <td>Affine</td> 2679 <td> 2680 Distort the image linearly by moving a list of at least 3 or more sets 2681 of control points (as defined below). Ideally 3 sets or 12 floating 2682 point values are given allowing the image to be linearly scaled, 2683 rotated, sheared, and translated, according to those three points. See 2684 also the related 'AffineProjection' and 'SRT' 2685 distortions. <br/> 2686 2687 More than 3 sets given control point pairs (12 numbers) is least 2688 squares fitted to best match a linear affine distortion. If only 2 2689 control point pairs (8 numbers) are given a two point image translation 2690 rotation and scaling is performed, without any possible shearing, 2691 flipping or changes in aspect ratio to the resulting image. If only one 2692 control point pair is provides the image is only translated, (which may 2693 be a floating point non-integer translation). <br/> 2694 2695 This distortion does not include any form of perspective distortion. 2696 </td> 2697 2698 </tr> 2699 2700 <tr> 2701 <td>AffineProjection</td> 2702 <td> 2703 Linearly distort an image using the given Affine Matrix of 6 2704 pre-calculated coefficients forming a set of Affine Equations to map 2705 the source image to the destination image. 2706 2707 <p class="text-center"><var> 2708 s<sub>x</sub>, r<sub>x</sub>, 2709 r<sub>y</sub>, s<sub>y</sub>, 2710 t<sub>x</sub>, t<sub>y</sub> 2711 </var></p> 2712 2713 See <a href="command-line-options.html#affine" >-affine</a> setting for more detail, and 2714 meanings of these coefficients. <br/> 2715 2716 The distortions 'Affine' and 'SRT' provide 2717 alternative methods of defining this distortion, with ImageMagick doing 2718 the calculations needed to generate the required coefficients. You can 2719 see the internally generated coefficients, by using a <a 2720 href="command-line-options.html#verbose" >-verbose</a> setting with those other variants. </td> 2721 2722 </tr> 2723 2724 <tr> 2725 <td>BilinearForward<br/> 2726 BilinearReverse</td> 2727 <td> 2728 Bilinear Distortion, given a minimum of 4 sets of coordinate pairs, or 2729 16 values (see below). Not that lines may not appear straight after 2730 distortion, though the distance between coordinates will remain 2731 consistent. <br/> 2732 2733 The 'BilinearForward' is used to map rectangles to any 2734 quadrilateral, while the 'BilinearReverse' form maps any 2735 quadrilateral to a rectangle, while preserving the straight line edges 2736 in each case. <br/> 2737 2738 Note that 'BilinearForward' can generate invalid pixels 2739 which will be colored using the <a href="command-line-options.html#alpha-color" >-alpha-color</a> 2740 color setting. Also if the quadrilateral becomes 'flipped' the image 2741 may disappear. <br/> 2742 2743 There are future plans to produce a true Bilinear distortion that will 2744 attempt to map any quadrilateral to any other quadrilateral, while 2745 preserving edges (and edge distance ratios). 2746 2747 </td> 2748 </tr> 2749 2750 <tr> 2751 <td>Perspective</td> 2752 <td> 2753 Perspective distort the images, using a list of 4 or more sets of 2754 control points (as defined below). More that 4 sets (16 numbers) of 2755 control points provide least squares fitting for more accurate 2756 distortions (for the purposes of image registration and panorama 2757 effects). Less than 4 sets will fall back to a 'Affine' 2758 linear distortion. <br/> 2759 2760 Perspective Distorted images ensures that straight lines remain 2761 straight, but the scale of the distorted image will vary. The horizon 2762 is anti-aliased, and the 'sky' color may be set using the 2763 <a href="command-line-options.html#alpha-color" >-alpha-color</a> setting. </td> 2764 </tr> 2765 2766 <tr> 2767 <td>PerspectiveProjection </td> 2768 <td> 2769 Do a 'Perspective' distortion biased on a set of 8 2770 pre-calculated coefficients. You can get these coefficients by looking 2771 at the <a href="command-line-options.html#verbose" >-verbose</a> output of a 2772 'Perspective' distortion, or by calculating them yourself. 2773 If the last two perspective scaling coefficients are zero, the 2774 remaining 6 represents a transposed 'Affine Matrix'. </td> 2775 2776 </tr> 2777 2778 <tr> 2779 <td>Arc</td> 2780 <td> 2781 Arc the image (variation of polar mapping) over the angle given around 2782 a circle. 2783 2784 <p><dl class="dl-horizontal"> 2785 <dt>arc_angle</dt> 2786 <dd>The angle over which to arc the image side-to-side</dd> 2787 <dt>rotate_angle</dt> 2788 <dd>Angle to rotate resulting image from vertical center</dd> 2789 <dt>top_radius</dt> 2790 <dd>Set top edge of source image at this radius</dd> 2791 <dt>bottom_radius </dt> 2792 <dd>Set bottom edge to this radius (radial scaling)</dd> 2793 </dl></p> 2794 2795 The resulting image is always resized to best fit the resulting image, 2796 (as if using <a href="command-line-options.html#distort" >+distort</a>) while attempting to 2797 preserve scale and aspect ratio of the original image as much as 2798 possible with the arguments given by the user. All four arguments will 2799 be needed to change the overall aspect ratio of an 'Arc'ed image. <br/> 2800 2801 This a variation of a polar distortion designed to try to preserve the 2802 aspect ratio of the image rather than direct Cartesian to Polar 2803 conversion. </td> 2804 </tr> 2805 2806 <tr> 2807 <td>Polar</td> 2808 <td> 2809 Like 'Arc' but do a complete Cartesian to Polar mapping of 2810 the image. that is the height of the input image is mapped to the 2811 radius limits, while the width is wrapped around between the 2812 angle limits. <br/> 2813 2814 Arguments: <var>Rmax,Rmin CenterX,CenterY, start,end_angle</var> <br/> 2815 2816 All arguments are optional. With <var>Rmin</var> defaulting to zero, the 2817 center to the center of the image, and the angles going from -180 (top) 2818 to +180 (top). If <var>Rmax</var> is given the special value of 2819 '0', the the distance from the center to the nearest edge 2820 is used for the radius of the output image, which will ensure the whole 2821 image is visible (though scaled smaller). However a special value of 2822 '-1' will use the distance from the center to the furthest 2823 corner, This may 'clip' the corners from the input rectangular image, 2824 but will generate the exact reverse of a 'DePolar' with 2825 the same arguments. <br/> 2826 2827 If the plus form of distort (<a href="command-line-options.html#distort" >+distort</a>) is used 2828 output image center will default to 0,0 of the virtual 2829 canvas, and the image size adjusted to ensure the whole input image is 2830 made visible in the output image on the virtual canvas. </td> 2831 2832 </tr> 2833 2834 <tr> 2835 <td>DePolar</td> 2836 <td> 2837 Uses the same arguments and meanings as a 'Polar' distortion 2838 but generates the reverse Polar to Cartesian distortion. <br/> 2839 2840 The special <var>Rmax</var> setting of '0' may however clip 2841 the corners of the input image. However using the special 2842 <var>Rmax</var> setting of '-1' (maximum center to corner 2843 distance) will ensure the whole distorted image is preserved in the 2844 generated result, so that the same argument to 'Polar' will 2845 reverse the distortion re-producing the original. 2846 2847 Note that as this distortion requires the area resampling of a circular 2848 arc, which can not be handled by the builtin EWA resampling function. 2849 As such the normal EWA filters are turned off. It is recommended some 2850 form of 'super-sampling' image processing technique be used to produce 2851 a high quality result. </td> 2852 2853 </tr> 2854 2855 <tr> 2856 <td>Barrel</td> 2857 <td> 2858 Given the four coefficients (A,B,C,D) as defined by <a 2859 href="http://wiki.panotools.org/Lens_correction_model" >Helmut 2860 Dersch</a>, perform a barrel or pin-cushion distortion appropriate to 2861 correct radial lens distortions. That is in photographs, make straight 2862 lines straight again. <br/> 2863 2864 <p class="text-center">Arguments: <var>A B C</var> [ <var>D</var> [ 2865 <var>X</var> , <var>Y</var> ] ] <br/> 2866 or <var>A<sub>x</sub> B<sub>x</sub> C<sub>x</sub> D<sub>x</sub> 2867 A<sub>y</sub> B<sub>y</sub> C<sub>y</sub> D<sub>y</sub></var> 2868 [ <var>X</var> , <var>Y</var> ] </p> 2869 So that it forms the function 2870 <p class="text-center">Rsrc = r * ( <var>A</var>*r<sup>3</sup> + <var>B</var>*r<sup>2</sup> + 2871 <var>C</var>*r + <var>D</var> )</p> 2872 2873 Where <var>X</var>,<var>Y</var> is the optional center of the distortion 2874 (defaulting to the center of the image). <br/> 2875 The second form is typically used to distort images, rather than 2876 correct lens distortions. <br/> 2877 </td> 2878 2879 </tr> 2880 2881 <tr> 2882 <td>BarrelInverse</td> 2883 <td> 2884 This is very similar to 'Barrel' with the same set of 2885 arguments, and argument handling. However it uses the inverse 2886 of the radial polynomial, 2887 so that it forms the function 2888 <p class="text-center">Rsrc = r / ( <var>A</var>*r<sup>3</sup> + <var>B</var>*r<sup>2</sup> + 2889 <var>C</var>*r + <var>D</var> )</p> 2890 Note that this is not the reverse of the 'Barrel' 2891 distortion, just a different barrel-like radial distortion method. 2892 2893 </td> 2894 </tr> 2895 2896 <tr> 2897 <td>Shepards</td> 2898 <td> 2899 Distort the given list control points (any number) using an Inverse 2900 Squared Distance Interpolation Method (<a 2901 href="http://en.wikipedia.org/wiki/Shepard%27s_method" >Shepards 2902 Method</a>). The control points in effect do 'localized' displacement 2903 of the image around the given control point (preserving the look and 2904 the rotation of the area near the control points. For best results 2905 extra control points should be added to 'lock' the positions of the 2906 corners, edges and other unchanging parts of the image, to prevent 2907 their movement. <br/> 2908 2909 The distortion has been likened to 'taffy pulling' using nails, or 2910 pins' stuck in a block of 'jelly' which is then moved to the new 2911 position, distorting the surface of the jelly. <br/> 2912 2913 Internally it is equivalent to generating a displacement map (see <a 2914 href="command-line-options.html#displace" >-displace</a>) for source image color look-up using 2915 the <a href="command-line-options.html#sparse-color" >-sparse-color</a> method of the same name. 2916 2917 </td> 2918 </tr> 2919 2920</table> 2921 2922<p>To print a complete list of distortion methods, use <a href="command-line-options.html#list">-list 2923distort</a>.</p> 2924 2925<p>Many of the above distortion methods such as '<code>Affine</code>', 2926'<code>Perspective</code>', and '<code>Shepards</code>' use a list control points 2927defining how these points in the given image should be distorted in the 2928destination image. Each set of four floating point values represent a source 2929image coordinate, followed immediately by the destination image coordinate. 2930This produces a list of values such as...</p> 2931<p class="text-center"><var> 2932 U<sub>1</sub>,V<sub>1</sub> X<sub>1</sub>,Y<sub>1</sub> 2933 U<sub>2</sub>,V<sub>2</sub> X<sub>2</sub>,Y<sub>2</sub> 2934 U<sub>3</sub>,V<sub>3</sub> X<sub>3</sub>,Y<sub>3</sub> 2935 ... 2936 U<sub>n</sub>,V<sub>n</sub> X<sub>n</sub>,Y<sub>n</sub> 2937</var></p> 2938<p>where <var>U,V</var> on the source image is mapped to <var>X,Y</var> on the 2939destination image. </p> 2940 2941<p>For example, to warp an image using '<code>perspective</code>' distortion, 2942needs a list of at least 4 sets of coordinates, or 16 numbers. Here is the 2943perspective distortion of the built-in "rose:" image. Note how spaces were 2944used to group the 4 sets of coordinate pairs, to make it easier to read and 2945understand.</p> 2946 2947<pre> 2948convert rose: -virtual-pixel black \ 2949 -distort Perspective '0,0,0,0 0,45,0,45 69,0,60,10 69,45,60,35' \ 2950 rose_3d_rotated.gif" 2951</pre> 2952 2953<p>If more that the required number of coordinate pairs are given for 2954a distortion, the distortion method is 'least squares' fitted to produce the 2955best result for all the coordinate pairs given. If less than the ideal number 2956of points are given, the distort will generally fall back to a simpler form of 2957distortion that can handles the smaller number of coordinates (usually a linear 2958'<code>Affine</code>' distortion). </p> 2959 2960<p>By using more coordinates you can make use of image registration tool to 2961find matching coordinate pairs in overlapping images, so as to improve the 2962'fit' of the distortion. Of course a bad coordinate pair can also make the 2963'fit' worse. Caution is always advised. </p> 2964 2965<p>Colors are acquired from the source image according to a cylindrical 2966resampling <a href="command-line-options.html#filter" >-filter</a>, using a special technique known as 2967EWA resampling. This produces very high quality results, especially when 2968images become smaller (minified) in the output, which is very common when 2969using '<code>perspective</code>' distortion. For example here we view 2970a infinitely tiled 'plane' all the way to the horizon. </p> 2971 2972<pre> 2973convert -size 90x90 pattern:checkerboard -normalize -virtual-pixel tile \ 2974 -distort perspective '0,0,5,45 89,0,45,46 0,89,0,89 89,89,89,89' \ 2975 checks_tiled.jpg 2976</pre> 2977 2978<p>Note that a infinitely tiled perspective images involving the horizon can 2979be very slow, because of the number of pixels that are compressed to generate 2980each individual pixel close to the 'horizon'. You can turn off EWA 2981resampling, by specifying the special <a href="command-line-options.html#filter" >-filter</a> setting of 2982'<code>point</code>' (recommended if you plan to use super-sampling instead). 2983</p> 2984 2985<p>If an image generates <i>invalid pixels</i>, such as the 'sky' in the last 2986example, <a href="command-line-options.html#distort" >-distort</a> will use the current <a 2987href="command-line-options.html#alpha-color" >-alpha-color</a> setting for these pixels. If you do not 2988what these pixels to be visible, set the color to match the rest of the 2989ground. </p> 2990 2991<p>The output image size will by default be the same as the input image. This 2992means that if the part of the distorted image falls outside the viewed area of 2993the 'distorted space', those parts is clipped and lost. However if you use 2994the plus form of the operator (<a href="command-line-options.html#distort" >+distort</a>) the operator 2995will attempt (if possible) to show the whole of the distorted image, while 2996retaining a correct 'virtual canvas' offset, for image layering. This offset 2997may need to be removed using <a href="command-line-options.html#repage" >+repage</a>, to remove if it 2998is unwanted. </p> 2999 3000<p>Setting <a href="command-line-options.html#verbose" >-verbose</a> setting, will cause <a 3001href="command-line-options.html#distort" >-distort</a> to attempt to output the internal coefficients, 3002and the <a href="command-line-options.html#fx" >-fx</a> equivalent to the distortion, for expert study, 3003and debugging purposes. This many not be available for all distorts. </p> 3004 3005<p>You can alternatively specify a special "<code><a href="command-line-options.html#define" 3006>-define</a> distort:viewport={geometry_string}</code>" setting which will 3007specify the size and the offset of the generated 'viewport' image of the 3008distorted image space.</p> 3009 3010<p>Setting a "<code><a href="command-line-options.html#define" >-define</a> 3011distort:scale=<var>scale_factor</var></code>" will scale the output image (viewport or 3012otherwise) by that factor without changing the viewed contents of the 3013distorted image. This can be used either for 'super-sampling' the image for 3014a higher quality result, or for panning and zooming around the image (with 3015appropriate viewport changes, or post-distort cropping and resizing). </p> 3016 3017<p>Setting "<code><a href="command-line-options.html#define" >-define</a> resample:verbose=1</code>" 3018will output the cylindrical filter lookup table created by the EWA (Elliptical 3019Weighted Average) resampling algorithm. Note this table uses a squared radius 3020lookup value. This is typically only used for debugging EWA resampling. </p> 3021 3022 3023<div style="margin: auto;"> 3024 <h3 class="magick-header"><a id="distribute-cache"></a>-distribute-cache <var>port</var></h3> 3025</div> 3026 3027<p class="magick-description">launch a distributed pixel cache server. </p> 3028 3029<div style="margin: auto;"> 3030 <h3 class="magick-header"><a id="dither"></a>-dither <var>method</var></h3> 3031</div> 3032 3033<p class="magick-description">Apply a Riemersma or Floyd-Steinberg error diffusion dither to 3034images when general color reduction is applied via an option, or automagically 3035when saving to specific formats. This enabled by default.</p> 3036 3037<p>Dithering places two or more colors in neighboring pixels so that to the 3038eye a closer approximation of the images original color is reproduced. This 3039reduces the number of colors needed to reproduce the image but at the cost of 3040a lower level pattern of colors. Error diffusion dithers can use any set of 3041colors (generated or user defined) to an image. </p> 3042 3043<p>Dithering is turned on by default, to turn it off use the plus form of the 3044setting, <a href="command-line-options.html#dither">+dither</a>. This will also also render PostScript 3045without text or graphic aliasing. Disabling dithering often (but not always) 3046leads to faster process, a smaller number of colors, but more cartoon like 3047image coloring. Generally resulting in 'color banding' effects in areas with 3048color gradients. </p> 3049 3050<p>The color reduction operators <a href="command-line-options.html#colors">-colors</a>, <a 3051href="command-line-options.html#monochrome">-monochrome</a>, <a href="command-line-options.html#remap ">-remap</a>, and <a 3052href="command-line-options.html#posterize">-posterize</a>, apply dithering to images using the reduced 3053color set they created. These operators are also used as part of automatic 3054color reduction when saving images to formats with limited color support, such 3055as <code>GIF:</code>, <code>XBM:</code>, and others, so dithering may also be used 3056in these cases. </p> 3057 3058<p>Alternatively you can use <a href="command-line-options.html#random-threshold">-random-threshold</a> 3059to generate purely random dither. Or use <a 3060href="command-line-options.html#ordered-dither">-ordered-dither</a> to apply threshold mapped dither 3061patterns, using uniform color maps, rather than specific color maps. </p> 3062 3063 3064<div style="margin: auto;"> 3065 <h3 class="magick-header"><a id="draw"></a>-draw <var>string</var></h3> 3066</div> 3067 3068<p class="magick-description">Annotate an image with one or more graphic primitives.</p> 3069 3070<p>Use this option to annotate or decorate an image with one or more graphic 3071primitives. The primitives include shapes, text, transformations, and pixel 3072operations.</p> 3073 3074<p>The shape primitives:</p> 3075 3076<dl class="dl-horizontal"> 3077<dt>point</dt><dd> x,y</dd> 3078<dt>line</dt><dd> x0,y0 x1,y1</dd> 3079<dt>rectangle</dt><dd> x0,y0 x1,y1</dd> 3080<dt>roundRectangle</dt><dd> x0,y0 x1,y1 wc,hc</dd> 3081<dt>arc</dt><dd> x0,y0 x1,y1 a0,a1</dd> 3082<dt>ellipse</dt><dd> x0,y0 rx,ry a0,a1</dd> 3083<dt>circle</dt><dd> x0,y0 x1,y1</dd> 3084<dt>polyline</dt><dd> x0,y0 ... xn,yn</dd> 3085<dt>polygon</dt><dd> x0,y0 ... xn,yn</dd> 3086<dt>bezier</dt><dd> x0,y0 ... xn,yn</dd> 3087<dt>path</dt><dd>specification </dd> 3088<dt>image</dt><dd> operator x0,y0 w,h filename</dd> 3089</dl> 3090 3091<p>The text primitive:</p> 3092 3093<dl class="dl-horizontal"> 3094<dt>text</dt><dd>x0,y0 string</dd> 3095</dl> 3096<p>The text gravity primitive:</p> 3097 3098<dl class="dl-horizontal"> 3099<dt>gravity</dt><dd>NorthWest, North, NorthEast, West, Center, East, SouthWest, South, or SouthEast</dd> 3100</dl> 3101 3102<p>The text gravity primitive only affects the placement of text and does not 3103interact with the other primitives. It is equivalent to using the <a 3104href="command-line-options.html#gravity">-gravity</a> command-line option, except that it is limited in 3105scope to the <a href="command-line-options.html#draw">-draw</a> option in which it appears.</p> 3106 3107<p>The transformation primitives:</p> 3108 3109<dl class="dl-horizontal"> 3110<dt>rotate</dt><dd>degrees</dd> 3111<dt>translate</dt><dd>dx,dy</dd> 3112<dt>scale</dt><dd>sx,sy</dd> 3113<dt>skewX</dt><dd>degrees</dd> 3114<dt>skewY</dt><dd>degrees</dd> 3115</dl> 3116 3117<p>The pixel operation primitives:</p> 3118 3119<dl class="dl-horizontal"> 3120<dt>color</dt><dd>x0,y0 method</dd> 3121<dt>matte</dt><dd>x0,y0 method</dd> 3122</dl> 3123 3124<p>The shape primitives are drawn in the color specified by the preceding <a 3125href="command-line-options.html#fill">-fill</a> setting. For unfilled shapes, use <a 3126href="command-line-options.html#fill">-fill none</a>. You can optionally control the stroke (the 3127"outline" of a shape) with the <a href="command-line-options.html#stroke">-stroke</a> and <a 3128href="command-line-options.html#strokewidth">-strokewidth</a> settings.</p> 3129 3130<p>A <code>point</code> primitive is specified by a single <var>point</var> in the 3131pixel plane, that is, by an ordered pair of integer coordinates, 3132<var>x</var>,<var>y</var>. (As it involves only a single pixel, a <code>point</code> 3133primitive is not affected by <a href="command-line-options.html#stroke">-stroke</a> or <a 3134href="command-line-options.html#strokewidth">-strokewidth</a>.)</p> 3135 3136<p>A <code>line</code> primitive requires a start point and end point.</p> 3137 3138<p>A <code>rectangle</code> primitive is specified by the pair of points at the 3139upper left and lower right corners.</p> 3140 3141<p>A <code>roundRectangle</code> primitive takes the same corner points as 3142a <code>rectangle</code> followed by the width and height of the rounded corners 3143to be removed.</p> 3144 3145<p>The <code>circle</code> primitive makes a disk (filled) or circle (unfilled). 3146Give the center and any point on the perimeter (boundary).</p> 3147 3148<p>The <code>arc</code> primitive is used to inscribe an elliptical segment in 3149to a given rectangle. An <code>arc</code> requires the two corners used for 3150<code>rectangle</code> (see above) followed by the start and end angles of the 3151arc of the segment segment (e.g. 130,30 200,100 45,90). The start and end 3152points produced are then joined with a line segment and the resulting segment 3153of an ellipse is filled.</p> 3154 3155<p>Use <code>ellipse</code> to draw a partial (or whole) ellipse. Give the 3156center point, the horizontal and vertical "radii" (the <var>semi-axes</var> of 3157the ellipse) and start and end angles in degrees (e.g. 100,100 100,150 31580,360).</p> 3159 3160<p>The <code>polyline</code> and <code>polygon</code> primitives require three or 3161more points to define their perimeters. A <code>polyline</code> is simply 3162a <code>polygon</code> in which the final point is not stroked to the start 3163point. When unfilled, this is a <var>polygonal line</var>. If the <a 3164href="command-line-options.html#stroke">-stroke</a> setting is <code>none</code> (the default), then 3165a <code>polyline</code> is identical to a <code>polygon</code>. </p> 3166 3167<p>A <var>coordinate</var> is a pair of integers separated by a space or 3168optional comma. </p> 3169 3170<p>As an example, to define a circle centered at 100,100 that extends to 3171150,150 use:</p> 3172 3173<pre> 3174-draw 'circle 100,100 150,150' 3175</pre> 3176 3177<p>The <code>Bezier</code> primitive creates a spline curve and requires three 3178or points to define its shape. The first and last points are the 3179<var>knots</var> and these points are attained by the curve, while any 3180intermediate coordinates are <var>control points</var>. If two control points 3181are specified, the line between each end knot and its sequentially respective 3182control point determines the tangent direction of the curve at that end. If 3183one control point is specified, the lines from the end knots to the one 3184control point determines the tangent directions of the curve at each end. If 3185more than two control points are specified, then the additional control points 3186act in combination to determine the intermediate shape of the curve. In order 3187to draw complex curves, it is highly recommended either to use the 3188<code>path</code> primitive or to draw multiple four-point bezier segments with 3189the start and end knots of each successive segment repeated. For example:</p> 3190 3191<pre> 3192-draw 'bezier 20,50 45,100 45,0 70,50' 3193-draw 'bezier 70,50 95,100 95,0 120,50' 3194</pre> 3195 3196<p>A <code>path</code> represents an outline of an object, defined in terms of 3197moveto (set a new current point), lineto (draw a straight line), curveto (draw 3198a Bezier curve), arc (elliptical or circular arc) and closepath (close the 3199current shape by drawing a line to the last moveto) elements. Compound paths 3200(i.e., a path with subpaths, each consisting of a single moveto followed by 3201one or more line or curve operations) are possible to allow effects such as 3202<var>donut holes</var> in objects. (See <a 3203href="http://www.w3.org/TR/SVG/paths.html">Paths</a>.)</p> 3204 3205<p>Use <code>image</code> to composite an image with another image. Follow the 3206image keyword with the composite operator, image location, image size, and 3207filename:</p> 3208 3209<pre> 3210-draw 'image SrcOver 100,100 225,225 image.jpg' 3211</pre> 3212 3213<p>You can use 0,0 for the image size, which means to use the actual 3214dimensions found in the image header. Otherwise, it is scaled to the given 3215dimensions. See <a href="compose.html">Alpha Compositing</a> for 3216a detailed discussion of alpha composition methods that are available. </p> 3217 3218<p>The "special augmented compose operators" such as "dissolve" that require 3219arguments cannot be used at present with the <code>-draw image</code> option. 3220 </p> 3221 3222<p>Use <code>text</code> to annotate an image with text. Follow the text 3223coordinates with a string. If the string has embedded spaces, enclose it in 3224single or double quotes.</p> 3225 3226<p>For example, the following annotates the image with <code>Works like 3227magick!</code> for an image titled <code>bird.miff</code>. </p> 3228 3229<pre> 3230-draw "text 100,100 'Works like magick!' " 3231</pre> 3232 3233<p>See the <a href="command-line-options.html#annotate">-annotate</a> option for another convenient way 3234to annotate an image with text.</p> 3235 3236<p>The <code>rotate</code> primitive rotates subsequent shape primitives and 3237text primitives about the origin of the main image. If the <a 3238href="command-line-options.html#region">-region</a> option precedes the <a href="command-line-options.html#draw">-draw</a> 3239option, the origin for transformations is the upper left corner of the 3240region.</p> 3241 3242<p>The <code>translate</code> primitive translates subsequent shape and text 3243primitives.</p> 3244 3245<p>The <code>scale</code> primitive scales them.</p> 3246 3247<p>The <code>skewX</code> and <code>skewY</code> primitives skew them with respect 3248to the origin of the main image or the region.</p> 3249 3250<p>The transformations modify the current affine matrix, which is initialized 3251from the initial affine matrix defined by the <a href="command-line-options.html#affine">-affine</a> 3252option. Transformations are cumulative within the <a href="command-line-options.html#draw">-draw</a> 3253option. The initial affine matrix is not affected; that matrix is only changed 3254by the appearance of another <a href="command-line-options.html#affine">-affine</a> option. If another 3255<a href="command-line-options.html#draw">-draw</a> option appears, the current affine matrix is 3256reinitialized from the initial affine matrix.</p> 3257 3258<p>Use the <code>color</code> primitive to change the color of a pixel to the 3259fill color (see <a href="command-line-options.html#fill">-fill</a>). Follow the pixel coordinate with 3260a method:</p> 3261 3262<pre> 3263point 3264replace 3265floodfill 3266filltoborder 3267reset 3268</pre> 3269 3270<p>Consider the target pixel as that specified by your coordinate. The 3271<code>point</code> method recolors the target pixel. The <code>replace</code> 3272method recolors any pixel that matches the color of the target pixel. 3273<code>Floodfill</code> recolors any pixel that matches the color of the target 3274pixel and is a neighbor, whereas <code>filltoborder</code> recolors any neighbor 3275pixel that is not the border color. Finally, <code>reset</code> recolors all 3276pixels.</p> 3277 3278<p>Use <code>matte</code> to the change the pixel matte value to transparent. 3279Follow the pixel coordinate with a method (see the <code>color</code> primitive 3280for a description of methods). The <code>point</code> method changes the matte 3281value of the target pixel. The <code>replace</code> method changes the matte 3282value of any pixel that matches the color of the target pixel. 3283<code>Floodfill</code> changes the matte value of any pixel that matches the 3284color of the target pixel and is a neighbor, whereas <code>filltoborder</code> 3285changes the matte value of any neighbor pixel that is not the border color (<a 3286href="command-line-options.html#bordercolor">-bordercolor</a>). Finally <code>reset</code> changes the 3287matte value of all pixels.</p> 3288 3289<p>You can set the primitive color, font, and font bounding box color with <a 3290href="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> 3291respectively. Options are processed in command line order so be sure to use 3292these options <var>before</var> the <a href="command-line-options.html#draw">-draw</a> option.</p> 3293 3294<p>Strings that begin with a number must be quoted (e.g. use '1.png' rather 3295than 1.png).</p> 3296 3297<p>Drawing primitives conform to the <a href="magick-vector-graphics.html" >Magick 3298Vector Graphics</a> format.</p> 3299 3300 3301<div style="margin: auto;"> 3302 <h3 class="magick-header"><a id="duplicate"></a>-duplicate <var>count,indexes</var></h3> 3303</div> 3304 3305<p class="magick-description">duplicate an image one or more times.</p> 3306 3307<p>Specify the count and the image to duplicate by its index in the sequence. 3308The first image is index 0. Negative indexes are relative to the end of the 3309sequence, for example, -1 represents the last image of the sequence. Specify 3310a range of images with a dash (e.g. 0-4). Separate indexes with a comma (e.g. 33110,2). Use <code>+duplicate</code> to duplicate the last image in the current 3312image sequence.</p> 3313 3314<div style="margin: auto;"> 3315 <h3 class="magick-header"><a id="edge"></a>-edge <var>radius</var></h3> 3316</div> 3317 3318<p class="magick-description">detect edges within an image.</p> 3319 3320<div style="margin: auto;"> 3321 <h3 class="magick-header"><a id="emboss"></a>-emboss <var>radius</var></h3> 3322</div> 3323 3324<p class="magick-description">emboss an image.</p> 3325 3326<div style="margin: auto;"> 3327 <h3 class="magick-header"><a id="encipher"></a>-encipher <var>filename</var></h3> 3328</div> 3329 3330<p class="magick-description">Encipher pixels for later deciphering by <a href="command-line-options.html#decipher">-decipher</a>.</p> 3331 3332<p>Get the passphrase from the file specified by <var>filename</var>.</p> 3333 3334<p>For more information, see the webpage, <a 3335href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or 3336Decipher an Image</a>.</p> 3337 3338 3339 3340<div style="margin: auto;"> 3341 <h3 class="magick-header"><a id="encoding"></a>-encoding <var>type</var></h3> 3342</div> 3343 3344<p class="magick-description">specify the text encoding.</p> 3345 3346<p>Choose from</p> 3347 3348<pre> 3349AdobeCustom AdobeExpert 3350AdobeStandard AppleRoman 3351BIG5 GB2312 3352Latin 2 None 3353SJIScode Symbol 3354Unicode Wansung 3355</pre> 3356 3357<div style="margin: auto;"> 3358 <h3 class="magick-header"><a id="endian"></a>-endian <var>type</var></h3> 3359</div> 3360 3361<p class="magick-description">Specify endianness (<code>MSB</code> or <code>LSB</code>) of the image.</p> 3362 3363<p>To print a complete list of endian types, use the <a href="command-line-options.html#list">-list endian</a> option.</p> 3364 3365<p>Use <a href="command-line-options.html#endian">+endian</a> to revert to unspecified endianness.</p> 3366 3367 3368<div style="margin: auto;"> 3369 <h3 class="magick-header"><a id="enhance"></a>-enhance</h3> 3370</div> 3371 3372<p class="magick-description">Apply a digital filter to enhance a noisy image.</p> 3373 3374 3375<div style="margin: auto;"> 3376 <h3 class="magick-header"><a id="equalize"></a>-equalize</h3> 3377</div> 3378 3379<p class="magick-description">perform histogram equalization on the image channel-by-channel.</p> 3380 3381<p>To perform histogram equalization on all channels in concert, transform the 3382image into some other color space, such as HSL, OHTA, YIQ or YUV, then 3383equalize the appropriate intensity-like channel, then convert back to RGB.</p> 3384 3385<p>For example using HSL, we have: ... <code>-colorspace HSL -channel lightness 3386-equalize -colorspace RGB</code> ...</p> 3387 3388<p>For YIQ, YUV and OHTA use the red channel. For example, OHTA is a principal 3389components transformation that puts most of the information in the first 3390channel. Here we have ... <code>-colorspace OHTA -channel red -equalize 3391-colorspace RGB</code> ...</p> 3392 3393<div style="margin: auto;"> 3394 <h3 class="magick-header"><a id="evaluate"></a>-evaluate <var>operator value</var></h3> 3395</div> 3396 3397<p class="magick-description">Alter channel pixels by evaluating an arithmetic, relational, or logical expression.</p> 3398 3399<p>(See the <a href="command-line-options.html#function" >-function</a> operator for some 3400multi-parameter functions. See the <a href="command-line-options.html#fx" >-fx</a> operator if more 3401elaborate calculations are needed.)</p> 3402 3403<p>The behaviors of each <var>operator</var> are summarized in the 3404following list. For brevity, the numerical value of a "pixel" referred to 3405below is the value of the corresponding channel of that pixel, while 3406a "normalized pixel" is that number divided by the maximum 3407(installation-dependent) value <var>QuantumRange</var>. (If 3408normalized pixels are used, they are restored, following the other 3409calculations, to the full range by multiplying by <var>QuantumRange</var>.)</p> 3410 3411<table class="table table-condensed table-striped"> 3412 <col width="25%" /> 3413 <col width="75%" /> 3414 <thead> 3415 <tr> 3416 <th><var>operator</var></th> 3417 <th>Summary (see further below for details)</th> 3418 </tr> 3419 </thead> 3420 <tbody> 3421 3422 <tr><td>Abs </td> <td>Add <var>value</var> to pixels and return absolute value. </td></tr> 3423 <tr><td>Add </td> <td>Add <var>value</var> to pixels. </td></tr> 3424 <tr><td>AddModulus </td> <td>Add <var>value</var> to pixels modulo <var>QuantumRange</var>.</td></tr> 3425 <tr><td>And </td> <td>Binary AND of pixels with <var>value</var>.</td></tr> 3426 <tr><td>Cos, Cosine </td> <td>Apply cosine to pixels with frequency <var>value</var> with 50% bias added.</td></tr> 3427 <tr><td>Divide </td> <td>Divide pixels by <var>value</var>.</td></tr> 3428 <tr><td>Exp </td> <td>base-e exponential function</td></tr> 3429 <tr><td>Exponential </td> <td>base-e exponential function</td></tr> 3430 <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> 3431 <tr><td>Log </td> <td>Apply scaled logarithm to normalized pixels.</td></tr> 3432 <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> 3433 <tr><td>Mean </td> <td>Add the <var>value</var> and divide by 2.</td></tr> 3434 <tr><td>Median </td> <td>Choose the median value from an image sequence.</td></tr> 3435 <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> 3436 <tr><td>Multiply </td> <td>Multiply pixels by <var>value</var>.</td></tr> 3437 <tr><td>Or </td> <td>Binary OR of pixels with <var>value</var>.</td></tr> 3438 <tr><td>Pow </td> <td>Raise normalized pixels to the power <var>value</var>.</td></tr> 3439 <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> 3440 <tr><td>RMS</td> <td>Square the pixel and add the <var>value</var>.</td></tr> 3441 <tr><td>RootMeanSquare</td> <td>Square the pixel and add the <var>value</var>.</td></tr> 3442 <tr><td>Set </td> <td>Set pixel equal to <var>value</var>.</td></tr> 3443 <tr><td>Sin, Sine </td> <td>Apply sine to pixels with frequency <var>value</var> with 50% bias added.</td></tr> 3444 <tr><td>Subtract </td> <td>Subtract <var>value</var> from pixels.</td></tr> 3445 <tr><td>Xor </td> <td>Binary XOR of pixels with <var>value.</var></td></tr> 3446 3447 <tr><td> </td><td> </td></tr> 3448 3449 <tr><td>Gaussian-noise</td><td> </td></tr> 3450 <tr><td>Impulse-noise</td><td> </td></tr> 3451 <tr><td>Laplacian-noise</td><td> </td></tr> 3452 <tr><td>Multiplicative-noise</td> <td>(These are equivalent to the corresponding <a href="command-line-options.html#noise" >-noise</a> operators.)</td></tr> 3453 <tr><td>PoissonNoise</td><td> </td></tr> 3454 <tr><td>Uniform-noise</td><td> </td></tr> 3455 3456 <tr><td> </td><td> </td></tr> 3457 3458 <tr><td>Threshold </td> <td>Threshold pixels larger than <var>value</var>.</td></tr> 3459 <tr><td>ThresholdBlack </td> <td>Threshold pixels to zero values equal to or below <var>value</var>.</td></tr> 3460 <tr><td>ThresholdWhite </td> <td>Threshold pixels to maximum values above <var>value</var>. </td></tr> 3461 </tbody> 3462 </table> 3463 3464<p>The specified functions are applied only to each previously set <a 3465href="command-line-options.html#channel" >-channel</a> in the image. If necessary, the results of the 3466calculations are truncated (clipped) to fit in the interval [0, <var>QuantumRange</var>]. The transparency channel of the image is 3467represented as a 'alpha' values (0 = fully transparent), so, for example, a 3468<code>Divide</code> by 2 of the alpha channel will make the image 3469semi-transparent. Append the percent symbol '<code>%</code>' to specify a value 3470as a percentage of the <var>QuantumRange</var>.</p> 3471 3472<p>To print a complete list of <a href="command-line-options.html#evaluate">-evaluate</a> operators, use 3473<a href="command-line-options.html#list">-list evaluate</a>.</p> 3474 3475<p>The results of the <code>Add</code>, <code>Subtract</code> and 3476<code>Multiply</code> methods can also be achieved using either the <a 3477href="command-line-options.html#level" >-level</a> or the <a href="command-line-options.html#level" >+level</a> operator, with 3478appropriate argument, to linearly modify the overall range of color values. 3479Please note, however, that <a href="command-line-options.html#level" >-level</a> treats transparency as 3480'matte' values (0 = opaque), while <a href="command-line-options.html#level" >-evaluate</a> works with 3481'alpha' values.</p> 3482 3483<p><code>AddModulus</code> has been added as of ImageMagick 6.4.8-4 and provides 3484addition modulo the <var>QuantumRange</var>. It is therefore 3485equivalent to <code>Add</code> unless the resulting pixel value is outside the 3486interval [0, <var>QuantumRange</var>]. </p> 3487 3488<p><code>Exp or Exponential</code> has been added as of ImageMagick 6.6.5-1 and 3489works on normalized pixel values. The <var>value</var> used with 3490<code>Exp</code> should be negative so as to produce a decaying exponential 3491function. Non-negative values will always produce results larger unity and 3492thus outside the interval [0, <var>QuantumRange</var>]. The 3493formula is expressed below. </p> 3494 3495<p class="text-center"> 3496exp(<var>value</var> × <b><var>u</var></b>) 3497</p> 3498 3499<p> If the input image is squared, for example, using <a href="command-line-options.html#-function" 3500>-function polynomial "2 0 0"</a>, then a decaying Gaussian function will be 3501the result.</p> 3502 3503<p><code>Log</code> has been added as of ImageMagick 6.4.2-1 and works on 3504normalized pixel values. This a <var>scaled</var> log function. The <var>value</var> used with <code>Log</code> provides a <var>scaling 3505factor</var> that adjusts the curvature in the graph of the log function. The 3506formula applied to a normalized value <b><var>u</var></b> is below. </p> 3507 3508<p class="text-center"> 3509log(<var>value</var> × <b><var>u</var></b> + 1) / log(<var>value</var> + 1) 3510</p> 3511 3512<p><code>Pow</code> has been added as of ImageMagick 6.4.1-9, and works on 3513normalized pixel values. Note that <code>Pow</code> is related to the <a 3514href="command-line-options.html#gamma" >-gamma</a> operator. For example, <b>-gamma 2</b> is equivalent 3515to <b>-evaluate pow 0.5</b>, i.e., a 'square root' function. The value used 3516with <a href="command-line-options.html#gamma" >-gamma</a> is simply the reciprocal of the value used 3517with <code>Pow</code>.</p> 3518 3519<p><code>Cosine</code> and <code>Sine</code> was added as of IM v6.4.8-8 and 3520converts the image values into a value according to a (co)sine wave function. 3521The synonyms <code>Cos</code> and <code>Sin</code> may also be used. The output 3522is biased 50% and normalized by 50% so as to fit in the respective color value 3523range. The <var>value</var> scaling of the <var>period</var> of the 3524function (its frequency), and thus determines the number of 'waves' that will 3525be 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, 3526then the effective period is the <var>half</var> the <var>QuantumRange</var>.</p> 3527 3528<p class="text-center"> 35290.5 + 0.5 × cos(2 π <b><var>u</var></b> × <var>value</var>). 3530</p> 3531 3532<p>See also the <a href="command-line-options.html#function" >-function</a> operator, which is a 3533multi-value version of evaluate. </p> 3534 3535<div style="margin: auto;"> 3536 <h3 class="magick-header"><a id="evaluate-sequence"></a>-evaluate-sequence <var>operator</var></h3> 3537</div> 3538 3539<p class="magick-description">Alter channel pixels by evaluating an arithmetic, relational, or 3540logical expression over a sequence of images.</p> 3541 3542<p>To print a complete list of <a 3543href="command-line-options.html#evaluate-sequence">-evaluate-sequence</a> operators, use <a 3544href="command-line-options.html#list">-list evaluate</a>.</p> 3545 3546<div style="margin: auto;"> 3547 <h3 class="magick-header"><a id="extent"></a>-extent <var>geometry</var></h3> 3548</div> 3549 3550<p class="magick-description">Set the image size and offset.</p> 3551 3552<p>If the image is enlarged, unfilled areas are set to the background color. 3553To position the image, use offsets in the <var>geometry</var> 3554specification or precede with a <a href="command-line-options.html#gravity">-gravity</a> setting. To 3555specify how to compose the image with the background, use <a href="command-line-options.html#compose" 3556>-compose</a>.</p> 3557 3558<p>This command reduces or expands a JPEG image to fit on an 800x600 3559display. If the aspect ratio of the input image isn't exactly 4:3, then the 3560image is centered on an 800x600 black canvas: </p> 3561 3562<pre> 3563convert input.jpg -resize 800x600 -background black -compose Copy \ 3564 -gravity center -extent 800x600 -quality 92 output.jpg 3565</pre> 3566 3567<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 3568 3569<div style="margin: auto;"> 3570 <h3 class="magick-header"><a id="extract"></a>-extract <var>geometry</var></h3> 3571</div> 3572 3573<p class="magick-description">Extract the specified area from image.</p> 3574 3575<p>This option is most useful for extracting a subregion of a very large raw 3576image. Note that these two commands are equivalent:</p> 3577 3578<pre> 3579convert -size 16000x16000 -depth 8 -extract 640x480+1280+960 \ 3580 image.rgb image.png", 3581convert -size 16000x16000 -depth 8 'image.rgb[640x480+1280+960]' \ 3582 image.rgb image.png" 3583</pre> 3584 3585<p>If you omit the offsets, as in</p> 3586 3587<pre> 3588convert -size 16000x16000 -depth 8 -extract 640x480 \ 3589 image.rgb image.png 3590</pre> 3591 3592<p>the image is <var>resized</var> to the specified dimensions instead, 3593equivalent to:</p> 3594 3595<pre> 3596convert -size 16000x16000 -depth 8 -resize 640x480 image.rgb image.png 3597</pre> 3598 3599<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 3600 3601<div style="margin: auto;"> 3602 <h3 class="magick-header"><a id="family"></a>-family <var>fontFamily</var></h3> 3603</div> 3604 3605<p class="magick-description">Set a font family for text.</p> 3606 3607<p>This setting suggests a font family that ImageMagick should try to use for 3608rendering text. If the family can be found it is used; if not, a default font 3609(e.g., "Arial") or a family known to be similar is substituted (e.g., 3610"Courier" might be used if "System" is requested but not found). </p> 3611 3612<p>For other settings that affect fonts, see the options <a 3613href="command-line-options.html#font">-font</a>, <a href="command-line-options.html#stretch">-stretch</a>, <a 3614href="command-line-options.html#style">-style</a>, and <a href="command-line-options.html#weight">-weight</a>. </p> 3615 3616<div style="margin: auto;"> 3617 <h3 class="magick-header"><a id="features"></a>-features <var>distance</var></h3> 3618</div> 3619 3620<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> 3621 3622<pre> 3623Angular Second Moment Sum Entropy 3624Contrast Entropy 3625Correlation Difference Variance 3626Sum of Squares Variance Difference Entropy 3627Inverse Difference Moment Information Measure of Correlation 1 3628Sum Average Information Measure of Correlation 2 3629Sum Variance Maximum Correlation Coefficient 3630</pre> 3631 3632<div style="margin: auto;"> 3633 <h3 class="magick-header"><a id="fft"></a>-fft</h3> 3634</div> 3635 3636<p class="magick-description">implements the forward discrete Fourier transform (DFT).</p> 3637 3638<p>This option is new as of ImageMagick 6.5.4-3 (and now working for Windows 3639users in ImageMagick 6.6.0-9). It transforms an image from the normal 3640(spatial) domain to the frequency domain. In the frequency domain, an image is 3641represented as a superposition of complex sinusoidal waves of varying 3642amplitudes. The image x and y coordinates are the possible frequencies along 3643the x and y directions, respectively, and the pixel intensity values are 3644complex numbers that correspond to the sinusoidal wave amplitudes. See for 3645example, <a href="http://en.wikipedia.org/wiki/Fourier_transform">Fourier 3646Transform</a>, <a href="http://en.wikipedia.org/wiki/DFT">Discrete Fourier 3647Transform</a> and <a href="http://en.wikipedia.org/wiki/FFT">Fast Fourier 3648Transform</a>.</p> 3649 3650<p>A single image name is provided as output for this option. However, the 3651output result will have two components. It is either a two-frame image or two 3652separate images, depending upon whether the image format specified supports 3653multi-frame images. The reason that we get a dual output result is because the 3654frequency domain represents an image using complex numbers, which cannot be 3655visualized directly. Therefore, the complex values are automagically separated 3656into a two-component image representation. The first component is the 3657magnitude of the complex number and the second is the phase of the complex 3658number. See for example, <a 3659href="http://en.wikipedia.org/wiki/Complex_numbers">Complex Numbers</a>.</p> 3660 3661<p>The magnitude and phase component images must be specified using image 3662formats that do not limit the color or compress the image. Thus, MIFF, TIF, 3663PFM, EXR and PNG are the recommended image formats to use. All of these 3664formats, except PNG support multi-frame images. So for example,</p> 3665 3666<pre> 3667convert image.png -fft fft_image.miff 3668</pre> 3669 3670<p>generates a magnitude image as <code>fft_image.miff[0]</code> and a phase 3671image as <code>fft_image.miff[1]</code>. Similarly,</p> 3672 3673<pre> 3674convert image.png -fft fft_image.png 3675</pre> 3676 3677<p>generates a magnitude image as <code>fft_image-0.png</code> and a phase image 3678as <code>fft_image-1.png</code>. If you prefer this representation, then you can 3679force any of the other formats to produce two output images by including <a 3680href="command-line-options.html#adjoin">+adjoin</a> following -fft in the command line.</p> 3681 3682<p>The input image can be any size, but if not square and even-dimensioned, it 3683is padded automagically to the larger of the width or height of the input 3684image and to an even number of pixels. The padding will occur at the bottom 3685and/or right sides of the input image. The resulting output magnitude and 3686phase images is square at this size. The kind of padding relies on the <a 3687href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting.</p> 3688 3689<p>Both output components will have dynamic ranges that fit within 3690[0, <var>QuantumRange</var>], so that HDRI need not be enabled. 3691Phase values nominally range from 0 to 2*π, but is scaled to span the full 3692dynamic range. (The first few releases had non-HDRI scaled but HDRI not 3693scaled). The magnitude image is not scaled and thus generally will contain 3694very small values. As such, the image normally will appear totally black. In 3695order to view any detail, the magnitude image typically is enhanced with a log 3696function into what is usually called the spectrum. A log function is used to 3697enhance the darker values more in comparison to the lighter values. This can 3698be done, for example, as follows:</p> 3699 3700<pre> 3701convert fft_image.miff[0] -contrast-stretch 0 \ 3702 -evaluate log 1000 fft_image_spectrum.png" 3703</pre> 3704 3705<p>where either <a href="command-line-options.html#contrast-stretch">-contrast-stretch</a> 0 or <a 3706href="command-line-options.html#auto-level">-auto-level</a> is used to scale the image to full dynamic 3707range, first. The argument to the <a href="command-line-options.html#evaluate">-evaluate</a> log 3708typically is specified between 100 and 10,000, depending upon the amount of 3709detail that one wants to bring out in the spectrum. Larger values produce more 3710visible detail. Too much detail, however, may hide the important features.</p> 3711 3712<p>The <a href="http://www.fftw.org/">FFTW</a> delegate library is required to 3713use <a href="command-line-options.html#fft">-fft</a>.</p> 3714 3715<p>Use <a href="command-line-options.html#fft">+fft</a> to produce two output images that are the real 3716and imaginary components of the complex valued Fourier transform.</p> 3717 3718<p>However, as the real and imaginary components can contain negative values, 3719this requires that IM be configured with HDRI enabled. In this case, you must 3720use either MIFF, TIF, PFM or MPC formats for the real and imaginary component 3721results, since they are formats that preserve both negative and fractional 3722values without clipping them or truncating the fractional part. With either 3723MIFF or TIF, one should add -define quantum:format=32, to allow those image 3724types to work properly in HDRI mode without clipping.</p> 3725 3726<p>The real and imaginary component images resulting from <a 3727href="command-line-options.html#fft">+fft</a> are also square, even dimensioned images due to the same 3728padding that was discussed above for the magnitude and phase component 3729images.</p> 3730 3731<p>See the discussion on HDRI implementations of ImageMagick on the page <a 3732href="high-dynamic-range.html" >High Dynamic-Range Images</a>. For more 3733about HDRI go the ImageMagick <a 3734href="http://www.imagemagick.org/Usage/basics/#hdri" >Usage</a> pages, <a 3735href="http://www.fmwconcepts.com/imagemagick/fourier_transforms/fourier.html" 3736>Fred's Fourier Processing With ImageMagick page</a> or this <a 3737 href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging" >Wikipedia</a> 3738 entry. </p> 3739 3740<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> 3741 3742 3743<div style="margin: auto;"> 3744 <h3 class="magick-header"><a id="fill"></a>-fill <var>color</var></h3> 3745</div> 3746 3747<p class="magick-description">color to use when filling a graphic primitive.</p> 3748 3749<p>This option accepts a color name, a hex color, or a numerical RGB, RGBA, 3750HSL, HSLA, CMYK, or CMYKA specification. See <a href="color.html" >Color Names</a> for 3751a description of how to properly specify the color argument.</p> 3752 3753<p>Enclose the color specification in quotation marks to prevent the "#" or 3754the parentheses from being interpreted by your shell.</p> 3755 3756<p>For example,</p> 3757 3758<pre> 3759-fill blue 3760-fill "#ddddff" 3761-fill "rgb(255,255,255)" 3762</pre> 3763 3764<p>See <a href="command-line-options.html#draw">-draw</a> for further details.</p> 3765 3766<p>To print a complete list of color names, use the <a href="command-line-options.html#list">-list color</a> option.</p> 3767 3768<div style="margin: auto;"> 3769 <h3 class="magick-header"><a id="filter"></a>-filter <var>type</var></h3> 3770</div> 3771 3772<p class="magick-description">Use this <var>type</var> of filter when resizing or distorting an image.</p> 3773 3774<p>Use this option to affect the resizing operation of an image during 3775operations such as <a href="command-line-options.html#resize">-resize</a> and <a href="command-line-options.html#distort" 3776>-distort</a>. For example you can use a simple resize filter such as:</p> 3777 3778<pre> 3779Point Hermite Cubic 3780Box Gaussian Catrom 3781Triangle Quadratic Mitchell 3782</pre> 3783 3784<p>The <code>Bessel</code> and <code>Sinc</code> filter is also provided (as well 3785as a faster <code>SincFast</code> equivalent form). However these filters are 3786generally useless on their own as they are infinite filters that are being 3787clipped to the filters support size. Their direct use is not recommended 3788except via expert settings (see below). </p> 3789 3790<p>Instead these special filter functions are typically windowed by a windowing 3791function that the <a href="command-line-options.html#filter" >-filter</a> setting defines. That is 3792using these functions will define a 'Windowed' filter, appropriate to the 3793operator involved. Windowed filters include: </p> 3794 3795<pre> 3796Lanczos Hamming Parzen 3797Blackman Kaiser Welsh 3798Hanning Bartlett Bohman 3799</pre> 3800 3801<p>Also one special self-windowing filter is also provided 3802<code>Lagrange</code>, which will automagically re-adjust its function depending 3803on the current 'support' or 'lobes' expert settings (see below).</p> 3804 3805<p>If you do not select a filter with this option, the filter defaults to 3806<code>Mitchell</code> for a colormapped image, an image with a matte channel, or 3807if the image is enlarged. Otherwise the filter default to 3808<code>Lanczos</code>.</p> 3809 3810<p>To print a complete list of resize filters, use the <a href="command-line-options.html#list">-list 3811filter</a> option.</p> 3812 3813<p>You can modify how the filter behaves as it scales your image through the 3814use of these expert settings (see also <a href="command-line-options.html#define" >-define</a> and <a 3815href="command-line-options.html#set" >-set</a>):-</p> 3816 3817<table class="table table-condensed table-striped"> 3818 <tr> 3819 <td>-define filter:blur=<var>factor</var></td> 3820 <td>Scale the X axis of the filter (and its window). Use > 1.0 for 3821 blurry or < 1.0 for sharp. This should only be used with Gaussian and 3822 Gaussian-like filters simple filters, or you may not get the expected 3823 results. </td> 3824 </tr> 3825 3826 <tr> 3827 <td>-define filter:support=<var>radius</var></td> 3828 <td>Set the filter support radius. Defines how large the filter should be and 3829 thus directly defines how slow the filtered resampling process is. All 3830 filters have a default 'preferred' support size. Some filters like 3831 <code>Lagrange</code> and windowed filters adjust themselves depending on 3832 this value. With simple filters this value either does nothing (but slow 3833 the resampling), or will clip the filter function in a detrimental way. 3834 </td> 3835 </tr> 3836 3837 <tr> 3838 <td>-define filter:lobes=<var>count</var></td> 3839 <td>Set the number of lobes to use for the Sinc/Bessel filter. This an 3840 alternative way of specifying the 'support' range of the filter, that is 3841 designed to be more suited to windowed filters, especially when used for 3842 image distorts.</td> 3843 </tr> 3844 3845 <tr> 3846 <td>-define filter:sigma=<var>value</var></td> 3847 <td>The 'sigma' value used to define the <code>Gaussian</code> filter. Default 3848 sigma value is '<code>0.5</code>'. It only effects <code>Gaussian</code> but 3849 does not shrink (but may enlarge) the filter's 'support'. It can be used 3850 to generate very small blurs but without the filter 'missing' pixels due 3851 to using a small support setting. A larger value of '<code>0.707</code>' 3852 (a value of '1/sqrt(2)') is another common setting. </td> 3853 </tr> 3854 3855 <tr> 3856 <td>-define filter:b=<var>b-spline_factor</var></td> 3857 <tr> 3858 <td>-define filter:c=<var>keys_alpha_factor</var></td> 3859 <td>Redefine the values used for cubic filters such as <code>Cubic</code>, 3860 <code>Catrom</code>, <code>Mitchel</code>, and <code>Hermite</code>, as well as 3861 the <code>Parzen</code> cubic windowing function. If only one of the values 3862 are defined, the other is set so as to generate a 'Cubic-Keys' filter. 3863 The values meaning was defined by a research paper by 3864 Mitchell-Netravali.</td> 3865 </tr> 3866 3867 <tr> 3868 <td>-define filter:kaiser-beta=<var>value</var></td> 3869 <td>The 'alpha' value used to as part of the Kaiser Windowing function. 3870 Default value is '6.5'. It only effects Kaiser windowing function, and 3871 does not effect any other attributes. 3872 Before ImageMagick v6.7.6-10, this option was known as "filter:alpha", (an 3873 inheritance from the very old "zoom" program). It was changed to bring the 3874 function in line with more modern academic research usage, and better 3875 assign it be more definitive. </td> 3876 </tr> 3877 3878 <tr> 3879 <td>-define filter:kaiser-alpha=<var>value</var></td> 3880 <td>This value when multiplied by 'PI' is equivalent to "kaiser-beta", and 3881 will override that setting. It only effects Kaiser windowing function, 3882 and does not effect any other attributes. </td> 3883 </tr> 3884 3885 <tr> 3886 <td>-define filter:filter=<var>filter_function</var></td> 3887 <td>Use this function directly as the weighting filter. This will allow 3888 you to directly use a windowing function such as <code>Blackman</code>, 3889 as a resampling filter, rather than as its normal usage as a windowing 3890 function. If defined, no windowing function also defined, the window function is set 3891 to <code>Box</code>). Directly specifying <code>Sinc</code> or <code>Jinc</code> 3892 as a filter will also do this. </td> 3893 </tr> 3894 3895 <tr> 3896 <td>-define filter:window=<var>filter_function</var></td> 3897 <td>The IIR (infinite impulse response) filters <code>Sinc</code> and 3898 <code>Jinc</code> are windowed (brought down to zero over the defined 3899 support range) with the given filter. This allows you to specify a filter 3900 function to be used as a windowing function for these IIR filters. 3901 Many of the defined filters are actually windowing functions for these IIR 3902 filters. A typical choices is <code>Box</code>, (which effectively turns 3903 off the windowing function). </td> 3904 </tr> 3905 3906 <tr> 3907 <td>-define filter:win-support=<var>radius</var></td> 3908 <td>Scale windowing function to this size instead. This causes the windowing 3909 (or self-windowing Lagrange filter) to act is if the support window is 3910 larger than what is actually supplied to the calling operator. The filter 3911 however is still clipped to the real support size given. If unset this 3912 will equal the normal filter support size. </td> 3913 </tr> 3914 3915 <tr> 3916 <td>-define filter:verbose=<var>1</var></td> 3917 <td>This causes IM to print information on the final internal filter 3918 selection to standard output. This includes a commented header on the 3919 filter settings being used, and data allowing the filter weights to be 3920 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 3921 a <code>SincFast</code> windowed <code>SincFast</code> filter, while 3922 <code>Mitchell</code> is defined as a general <code>Cubic</code> family filter 3923 with specific 'B' and 'C' settings. </td> 3924 </tr> 3925 3926</table> 3927 3928<p>For example, to get a 8 lobe jinc windowed sinc filter (Genseng filter?):</p> 3929 3930<pre> 3931convert image.png \ 3932 -filter sinc \ 3933 -set filter:window=jinc \ 3934 -set filter:lobes=8 \ 3935 -resize 150% image.jpg" 3936</pre> 3937 3938<p>Or a raw un-windowed Sinc filter with 4 lobes:</p> 3939 3940<pre> 3941convert image.png \ 3942 -set filter:filter=sinc \ 3943 -set filter:lobes=4 \ 3944 -resize 150% image.jpg" 3945</pre> 3946 3947<p>To extract the data for a raw windowing function, combine it with 3948a '<code>Box</code>' filter. For example the '<code>Welch</code> parabolic 3949windowing function. </p> 3950 3951<pre> 3952convert null: -define filter:filter=Box \ 3953 -define filter:window=Welch \ 3954 -define filter:support=1.0 \ 3955 -define filter:verbose=1 \ 3956 -resize 2 null: > window_welch.dat 3957gnuplot 3958 set grid 3959 plot \"window_welch.dat\" with lines 3960</pre> 3961 3962<p>Note that the use of expert options is provided for image processing experts 3963who have studied and understand how resize filters work. Without this 3964knowledge, and an understanding of the definition of the actual filters 3965involved, using expert settings are more likely to be detrimental to your image 3966resizing.</p> 3967 3968 3969<div style="margin: auto;"> 3970 <h3 class="magick-header"><a id="flatten"></a>-flatten</h3> 3971</div> 3972 3973<p class="magick-description">This is a simple alias for the <a href="command-line-options.html#layers" >-layers</a> method "flatten".</p> 3974 3975 3976<div style="margin: auto;"> 3977 <h3 class="magick-header"><a id="flip"></a>-flip</h3> 3978</div> 3979 3980<p class="magick-description">create a <var>mirror image</var></p> 3981 3982<p>reflect the scanlines in the vertical direction. The image will be mirrored 3983upside-down. </p> 3984 3985 3986<div style="margin: auto;"> 3987 <h3 class="magick-header"><a id="floodfill"></a>-floodfill {<var>+-</var>}<var>x</var>{<var>+-</var>}<var>y</var> <var>color</var></h3> 3988</div> 3989 3990<p class="magick-description">floodfill the image with color at the specified offset.</p> 3991 3992<p>Flood fill starts from the given 'seed point' which is not gravity effected. 3993Any color that matches within <a href="command-line-options.html#fuzz" >-fuzz</a> color distance of the 3994given <var>color</var> argument, connected to that 'seed point' 3995will be replaced with the current <a href="command-line-options.html#fill" >-fill</a> color. </p> 3996 3997<p>Note that if the pixel at the 'seed point' does not itself match the given 3998<var>color</var> (according to <a href="command-line-options.html#fuzz" >-fuzz</a>), then no 3999action will be taken. </p> 4000 4001<p>This operator works more like the <a href="command-line-options.html#opaque" >-opaque</a> option, than 4002a more general flood fill that reads the matching color directly at the 'seed 4003point'. For this form of flood fill, look at <a href="command-line-options.html#draw" >-draw</a> and 4004its 'color floodfill' drawing method. </p> 4005 4006 4007<div style="margin: auto;"> 4008 <h3 class="magick-header"><a id="flop"></a>-flop</h3> 4009</div> 4010 4011<p class="magick-description">create a <var>mirror image</var>.</p> 4012 4013<p>Reflect the scanlines in the horizontal direction, just like the image in 4014a vertical mirror. </p> 4015 4016 4017<div style="margin: auto;"> 4018 <h3 class="magick-header"><a id="font"></a>-font <var>name</var></h3> 4019</div> 4020 4021<p class="magick-description">set the font to use when annotating images with text, or creating labels.</p> 4022 4023<p>To print a complete list of fonts, use the <a href="command-line-options.html#list">-list font</a> 4024option (for versions prior to 6.3.6, use 'type' instead of 'font').</p> 4025 4026<p>In addition to the fonts specified by the above pre-defined list, you can 4027also specify a font from a specific source. For example <code>Arial.ttf</code> 4028is a TrueType font file, <code>ps:helvetica</code> is PostScript font, and 4029<code>x:fixed</code> is X11 font.</p> 4030 4031<p>For other settings that affect fonts, see the options <a 4032href="command-line-options.html#family">-family</a>, <a href="command-line-options.html#stretch">-stretch</a>, <a 4033href="command-line-options.html#style">-style</a>, and <a href="command-line-options.html#weight">-weight</a>. </p> 4034 4035 4036<div style="margin: auto;"> 4037 <h3 class="magick-header"><a id="foreground"></a>-foreground <var>color</var></h3> 4038</div> 4039 4040<p class="magick-description">Define the foreground color for menus.", "display</p> 4041 4042<p>The color is specified using the format described under the <a 4043href="command-line-options.html#fill">-fill</a> option.</p> 4044 4045<p>The default foreground color is black.</p> 4046 4047<div style="margin: auto;"> 4048 <h3 class="magick-header"><a id="format"></a>-format <var>type</var></h3> 4049</div> 4050 4051<p class="magick-description">the image format type.</p> 4052 4053<p>When used with the <code>mogrify</code> utility, this option converts any 4054image to the image <a href="formats.html">format</a> you specify. 4055For a list of image format types supported by ImageMagick, use <a 4056href="command-line-options.html#list">-list format</a>.</p> 4057 4058<p>By default the file is written to its original name. However, if the 4059filename extension matches a supported format, the extension is replaced with 4060the image format type specified with <a href="command-line-options.html#format">-format</a>. For 4061example, if you specify <var>tiff</var> as the format type and the 4062input image filename is <var>image.gif</var>, the output image 4063filename becomes <var>image.tiff</var>.</p> 4064 4065<div style="margin: auto;"> 4066 <h3 class="magick-header"><a id="format_identify_"></a>-format <var>string</var></h3> 4067</div> 4068 4069<p class="magick-description">output formatted image characteristics.</p> 4070 4071<p>See <a href="escape.html">Format and Print Image 4072Properties</a> for an explanation on how to specify the argument to this 4073option.</p> 4074 4075<div style="margin: auto;"> 4076 <h3 class="magick-header"><a id="frame"></a>-frame <var>geometry</var></h3> 4077</div> 4078 4079<p class="magick-description">Surround the image with a border or beveled frame.</p> 4080 4081<p>The color of the border is specified with the <a href="command-line-options.html#alpha-color" 4082>-alpha-color</a> command line option. </p> 4083 4084<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 4085height that is added to the dimensions of the image. If no offsets are given 4086in the <var>geometry</var> argument, then the border added is 4087a solid color. Offsets <var>x</var> and <var>y</var>, if present, specify that 4088the width and height of the border is partitioned to form an outer bevel of 4089thickness <var>x</var> pixels and an inner bevel of thickness 4090<var>y</var> pixels. Negative offsets make no sense as frame arguments. 4091</p> 4092 4093<p>The <a href="command-line-options.html#frame">-frame</a> option is affected by the current <a 4094href="command-line-options.html#compose">-compose</a> setting and assumes that this is using the default 4095'<code>Over</code>' composition method. It generates an image of the appropriate 4096size with the current <a href="command-line-options.html#bordercolor">-bordercolor</a> setting, and then 4097draws the frame of four distinct colors close to the current <a 4098href="command-line-options.html#alpha-color">-alpha-color</a>. The original image is then overlaid onto 4099center of this image. This means that with the default compose method of 4100'<code>Over</code>' any transparent parts may be replaced by the current <a 4101href="command-line-options.html#bordercolor">-bordercolor</a> setting.</p> 4102 4103<p>The image composition is not 4104affected by the <a href="command-line-options.html#gravity">-gravity</a> option.</p> 4105 4106 4107<div style="margin: auto;"> 4108 <h3 class="magick-header"><a id="frame_import_"></a>-frame</h3> 4109</div> 4110 4111<p class="magick-description">include the X window frame in the imported image. </p> 4112<div style="margin: auto;"> 4113 <h3 class="magick-header"><a id="function"></a>-function <var>function</var> <var>parameters</var></h3> 4114</div> 4115 4116<p class="magick-description">Apply a function to channel values.</p> 4117 4118<p>This operator performs calculations based on the given arguments to modify 4119each of the color values for each previously set <a 4120href="command-line-options.html#channel">-channel</a> in the image. See <a 4121href="command-line-options.html#evaluate">-evaluate</a> for details concerning how the results of the 4122calculations are handled.</p> 4123 4124<p>This is can be considered a multi-argument version of the <a 4125href="command-line-options.html#evaluate">-evaluate</a> operator. (Added in 4126ImageMagick 6.4.8−8.)</p> 4127 4128<p>Here, <var>parameters</var> is a comma-separated list of 4129numerical values. The number of values varies depending on which <var>function</var> is selected. Choose the <var>function</var> from:</p> 4130 4131<pre> 4132Polynomial 4133Sinusoid 4134Arcsin 4135Arctan 4136</pre> 4137 4138<p>To print a complete list of <a href="command-line-options.html#function">-function</a> operators, 4139use <a href="command-line-options.html#list">-list function</a>. Descriptions follow.</p> 4140 4141<dl class="dl-horizontal"> 4142 <dt>Polynomial</dt> 4143 <dd><p>The <code>Polynomial</code> function takes an arbitrary number of parameters, 4144these being the coefficients of a polynomial, in decreasing order of degree. 4145That is, entering</p> 4146 4147<pre> 4148-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> 4149</pre> 4150 4151<p>will invoke a polynomial function given by</p> 4152 4153<pre> 4154<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>, 4155</pre> 4156 4157<p>where <b><var>u</var></b> is pixel's original normalized channel value.</p> 4158 4159<p>The <code>Polynomial</code> function can be used in place of <code>Set</code> 4160(the <var>constant</var> polynomial) and <code>Add</code>, <code>Divide</code>, 4161<code>Multiply</code>, and <code>Subtract</code> (some <var>linear</var> 4162polynomials) of the <a href="command-line-options.html#evaluate">-evaluate</a> operator. The <a 4163href="command-line-options.html#level">-level</a> operator also affects channels linearly. Some 4164correspondences follow.</p> 4165 4166<table class="table table-condensed table-striped"> 4167 <tr> 4168 <td>-evaluate Set <var>value</var> </td> 4169 <td>-function Polynomial <var>value</var></td> 4170 <td>(Constant functions; set <var>value</var>×100% gray when channels are RGB.)</td> 4171 </tr> 4172 <tr> 4173 <td>-evaluate Add <var>value</var> </td> 4174 <td>-function Polynomial 1,<var>value</var></td> 4175 </tr> 4176 <tr> 4177 <td>-evaluate Subtract <var>value</var> </td> 4178 <td>-function Polynomial 1,−<var>value</var></td> 4179 </tr> 4180 <tr> 4181 <td>-evaluate Multiply <var>value</var> </td> 4182 <td>-function Polynomial <var>value</var>,0</td> 4183 </tr> 4184 <tr> 4185 <td>+level black% x white%</td> 4186 <td>-function Polynomial A,B</td> 4187 <td>(Reduce contrast. Here, A=(white-black)/100 and B=black/100.)</td> 4188 </tr> 4189</table> 4190 4191<p>The <code>Polynomial</code> function gives great versatility, since 4192polynomials can be used to fit any continuous curve to any degree of accuracy 4193desired.</p> 4194 4195</dd> 4196<dt>Sinusoid</dt> 4197<dd> 4198<p>The <code>Sinusoid</code> function can be used to vary the channel values 4199sinusoidally by setting frequency, phase shift, amplitude, and a bias. These 4200values are given as one to four parameters, as follows,</p> 4201 4202<pre> 4203-function <code>Sinusoid</code> <var>freq</var>,[<var>phase</var>,[<var>amp</var>,[<var>bias</var>]]] 4204</pre> 4205 4206<p>where <var>phase</var> is in degrees. (The domain [0,1] of the function 4207corresponds to 0 through <var>freq</var>×360 degrees.) 4208The result is that if a pixel's normalized channel value is originally 4209<b><var>u</var></b>, its resulting normalized value is given by </p> 4210 4211<pre> 4212<var>amp</var> * sin(2*π* (<var>freq</var> * <b><var>u</var></b> + <var>phase</var> / 360)) + <var>bias</var> 4213</pre> 4214 4215<p> For example, the following generates a curve that starts and ends at 0.9 4216(when <b><var>u</var></b>=0 and 1, resp.), oscillating three times between 4217.7−.2=.5 and .7+.2=.9. </p> 4218 4219<pre> 4220-function Sinusoid 3,-90,.2,.7 4221</pre> 4222 4223<p>The default values of <var>amp</var> and <var>bias</var> are both .5. The default for <var>phase</var> 4224is 0.</p> 4225 4226<p>The <code>Sinusoid</code> function generalizes <code>Sin</code> and 4227<code>Cos</code> of the <a href="command-line-options.html#evaluate">-evaluate</a> operator by allowing 4228varying amplitude, phase and bias. The correspondence is as follows.</p> 4229 4230<table class="table table-condensed table-striped"> 4231 <tr> 4232 <td>-evaluate Sin <var>freq</var> </td> 4233 <td>-function Sinusoid <var>freq</var>,0 </td> 4234 </tr> 4235 <tr> 4236 <td>-evaluate Cos <var>freq</var> </td> 4237 <td>-function Sinusoid <var>freq</var>,90 </td> 4238 </tr> 4239</table> 4240 </dd> 4241<dt>ArcSin</dt> 4242<dd> 4243<p>The <code>ArcSin</code> function generates the inverse curve of a Sinusoid, 4244and can be used to generate cylindrical distortion and displacement maps. 4245The curve can be adjusted relative to both the input values and output range 4246of values.</p> 4247 4248<pre> 4249-function <code>ArcSin</code> <var>width</var>,[<var>center</var>,[<var>range</var>,[<var>bias</var>]]] 4250</pre> 4251 4252<p>with all values given in terms of normalized color values (0.0 for black, 42531.0 for white). Defaulting to values covering the full range from 0.0 to 1.0 4254for bout input (<var>width</var>), and output (<var>width</var>) values. '<code>1.0,0.5,1.0,0.5</code>' </p> 4255 4256<pre> 4257<var>range</var>/π * asin( 2/<var>width</var> * ( <b><var>u</var></b> - <var>center</var> ) ) + <var>bias</var> 4258</pre> 4259 4260</dd> 4261<dt>ArcTan</dt> 4262<dd> 4263<p>The <code>ArcTan</code> function generates a curve that smooth crosses from 4264limit values at infinities, though a center using the given slope value. 4265All these values can be adjusted via the arguments.</p> 4266 4267<pre> 4268-function <code>ArcTan</code> <var>slope</var>,[<var>center</var>,[<var>range</var>,[<var>bias</var>]]] 4269</pre> 4270 4271<p>Defaulting to '<code>1.0,0.5,1.0,0.5</code>'. 4272</p> 4273 4274<pre> 4275<var>range</var>/π * atan( <var>slope</var>*π * ( <b><var>u</var></b> - <var>center</var> ) ) + <var>bias</var> 4276</pre> 4277 </dd> 4278 </tr> 4279</dl> 4280 4281 4282 4283<div style="margin: auto;"> 4284 <h3 class="magick-header"><a id="fuzz"></a>-fuzz <var>distance</var>{<var>%</var>}</h3> 4285</div> 4286 4287<p class="magick-description">Colors within this <var>distance</var> are considered equal.</p> 4288 4289<p>A number of algorithms search for a target color. By default the color must 4290be exact. Use this option to match colors that are close to the target color 4291in RGB space. For example, if you want to automagically trim the edges of an 4292image with <a href="command-line-options.html#trim">-trim</a> but the image was scanned and the target 4293background color may differ by a small amount. This option can account for 4294these differences.</p> 4295 4296<p>The <var>distance</var> can be in absolute intensity units or, by 4297appending <code>%</code> as a percentage of the maximum possible intensity (255, 429865535, or 4294967295).</p> 4299 4300<p>Use <a href="command-line-options.html#fuzz" >+fuzz</a> to reset the fuzz value to 0.</p> 4301 4302 4303<div style="margin: auto;"> 4304 <h3 class="magick-header"><a id="fx"></a>-fx <var>expression</var></h3> 4305</div> 4306 4307<p class="magick-description">apply a mathematical expression to an image or image channels.</p> 4308 4309<p>If the first character of <var>expression</var> is <code>@</code>, 4310the expression is read from a file titled by the remaining characters in the 4311string.</p> 4312 4313<p>See <a href="fx.html">FX, 4314The Special Effects Image Operator</a> for a detailed discussion of this 4315option.</p> 4316 4317 4318<div style="margin: auto;"> 4319 <h3 class="magick-header"><a id="gamma"></a>-gamma <var>value</var></h3> 4320</div> 4321 4322<p class="magick-description">level of gamma correction.</p> 4323 4324<p>The same color image displayed on two different workstations may look 4325different due to differences in the display monitor. Use gamma correction to 4326adjust for this color difference. Reasonable values extend from 4327<code>0.8</code> to <code>2.3</code>. Gamma less than 1.0 darkens the image and 4328gamma greater than 1.0 lightens it. Large adjustments to image gamma may 4329result in the loss of some image information if the pixel quantum size is only 4330eight bits (quantum range 0 to 255).</p> 4331 4332<p>Gamma adjusts the image's channel values pixel-by-pixel according to 4333a power law, namely, pow(pixel,1/gamma) or pixel^(1/gamma), where pixel is the 4334normalized or 0 to 1 color value. For example, using a value of gamma=2 is the 4335same as taking the square root of the image.</p> 4336 4337<p>You can apply separate gamma values to the red, green, and blue channels of 4338the image with a gamma value list delimited with commas (e.g., 4339<code>1.7,2.3,1.2</code>).</p> 4340 4341<p>Use <a href="command-line-options.html#gamma">+gamma <var>value</var></a> to set the 4342image gamma level without actually adjusting the image pixels. This option 4343is useful if the image is of a known gamma but not set as an image attribute 4344(e.g. PNG images). Write the "file gamma" which is the reciprocal of the 4345display gamma; e.g., if your image is sRGB and you want to write a PNG gAMA 4346chunk, use</p> 4347 4348<pre> 4349convert input.png +gamma .45455 output.png 4350</pre> 4351 4352<p>(0.45455 is 1/2.2)</p> 4353 4354<p>Note that gamma adjustments are also available via the <a href="command-line-options.html#level">-level</a> operator.</p> 4355 4356<div style="margin: auto;"> 4357 <h3 class="magick-header"><a id="gaussian-blur"></a>-gaussian-blur <var>radius</var><br />-gaussian-blur <var>radius</var>x<var>sigma</var></h3> 4358</div> 4359 4360<p class="magick-description">Blur the image with a Gaussian operator.</p> 4361 4362<p>Convolve the image with a Gaussian or normal distribution using the given 4363<var >Sigma</var> value. The formula is:</p> 4364 4365<p class="text-center"><img class="img-thumbnail" alt="gaussian distribution" width="243px" height="42px" src="../images/gaussian-blur.png"/> </p> 4366 4367<p>The <var >Sigma</var> value is the important argument, and 4368determines the actual amount of blurring that will take place. </p> 4369 4370<p>The <var >Radius</var> is only used to determine the size of the 4371array which will hold the calculated Gaussian distribution. It should be an 4372integer. If not given, or set to zero, IM will calculate the largest possible 4373radius that will provide meaningful results for the Gaussian distribution. 4374</p> 4375 4376<p>The larger the <var >Radius</var> the radius the slower the 4377operation is. However too small a <var >Radius</var>, and sever 4378aliasing effects may result. As a guideline, <var >Radius</var> 4379should be at least twice the <var >Sigma</var> value, though three 4380times will produce a more accurate result. </p> 4381 4382<p>This differs from the faster <a href="command-line-options.html#blur">-blur</a> operator in that a 4383full 2-dimensional convolution is used to generate the weighted average of the 4384neighboring pixels. </p> 4385 4386<p>The <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting will determine how 4387pixels which are outside the image proper are blurred into the final result. 4388</p> 4389 4390 4391<div style="margin: auto;"> 4392 <h3 class="magick-header"><a id="geometry"></a>-geometry <var>geometry</var></h3> 4393</div> 4394 4395<p class="magick-description">Set the preferred size and location of the image.</p> 4396 4397<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 4398 4399<div style="margin: auto;"> 4400 <h3 class="magick-header"><a id="gravity"></a>-gravity <var>type</var></h3> 4401</div> 4402 4403<p class="magick-description">Sets the current gravity suggestion for various other settings and options.</p> 4404 4405<p>Choices include: <code>NorthWest</code>, <code>North</code>, 4406<code>NorthEast</code>, <code>West</code>, <code>Center</code>, <code>East</code>, 4407<code>SouthWest</code>, <code>South</code>, <code>SouthEast</code>. Use <a 4408href="command-line-options.html#list">-list gravity</a> to get a complete list of <a 4409href="command-line-options.html#gravity">-gravity</a> settings available in your ImageMagick 4410installation.</p> 4411 4412<p>The direction you choose specifies where to position text or subimages. For 4413example, a gravity of <code>Center</code> forces the text to be centered within 4414the image. By default, the image gravity is <code>undefined</code>. See <a 4415href="command-line-options.html#draw">-draw</a> for more details about graphic primitives. Only the 4416text primitive of <a href="command-line-options.html#draw">-draw</a> is affected by the <a 4417href="command-line-options.html#gravity">-gravity</a> option.</p> 4418 4419<p>The <a href="command-line-options.html#gravity">-gravity</a> option is also used in concert with the 4420<a href="command-line-options.html#geometry">-geometry</a> setting and other settings or options that 4421take <var>geometry</var> as an argument, such as the <a 4422href="command-line-options.html#crop">-crop</a> option. </p> 4423 4424<p>If a <a href="command-line-options.html#gravity">-gravity</a> setting occurs before another option 4425or setting having a <var>geometry</var> argument that specifies an 4426offset, the offset is usually applied to the point within the image suggested 4427by the <a href="command-line-options.html#gravity">-gravity</a> argument. Thus, in the following 4428command, for example, suppose the file <code>image.png</code> has dimensions 4429200x100. The offset specified by the argument to <a href="command-line-options.html#region">-region</a> 4430is (−40,+20). The argument to <a href="command-line-options.html#gravity">-gravity</a> is 4431<code>Center</code>, which suggests the midpoint of the image, at the point 4432(100,50). The offset (−40,20) is applied to that point, giving 4433(100−40,50+20)=(60,70), so the specified 10x10 region is located at 4434that point. (In addition, the <a href="command-line-options.html#gravity">-gravity</a> affects the 4435region itself, which is <var>centered</var> at the pixel 4436coordinate (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> 4437 4438<pre> 4439convert image.png -gravity Center -region 10x10-40+20 \ 4440 -negate output.png 4441</pre> 4442 4443<p>When used as an option to <a href="composite.html">composite</a>, <a 4444href="command-line-options.html#gravity">-gravity</a> gives the direction that the image gravitates 4445within the composite.</p> 4446 4447<p>When used as an option to <a href="montage.html">montage</a>, <a 4448href="command-line-options.html#gravity">-gravity</a> gives the direction that an image gravitates 4449within a tile. The default gravity is <code>Center</code> for this purpose.</p> 4450 4451 4452<div style="margin: auto;"> 4453 <h3 class="magick-header"><a id="grayscale"></a>-grayscale <var>method</var></h3> 4454</div> 4455 4456<p class="magick-description">convert image to grayscale.</p> 4457 4458<p>This will use one of the <a href="command-line-options.html#intensity" >-intensity</a> methods to 4459convert the given image into a linear-grayscale image. </p> 4460 4461<p>For example, to convert an image to (linear) Rec709Luminance grayscale, type:</p> 4462 4463<pre> 4464convert in.png -grayscale Rec709Luminance out.png 4465</pre> 4466 4467<p>which is equivalent to:</p> 4468 4469<pre> 4470convert in.png -colorspace gray out.png 4471</pre> 4472 4473<p>Similarly, to convert an image to (non-linear) Rec709Luma grayscale, type:</p> 4474 4475<pre> 4476convert in.png -grayscale Rec709Luma out.png 4477</pre> 4478 4479<p>which is equivalent to:</p> 4480 4481<pre> 4482convert in.png -set colorspace RGB -colorspace gray out.png 4483</pre> 4484 4485<p>Note that a 'colorspace' intensity method will produce the same result 4486regardless of the current colorpsace of the image. But a 'mathematical' 4487intensity method will depend on the current colorspace the image is currently 4488using. </p> 4489 4490<p>While this operation uses an <a href="command-line-options.html#intensity" >-intensity</a> method, 4491it does not use or set the <a href="command-line-options.html#intensity" >-intensity</a> setting, so 4492will not effect other operations that may use that setting.</p> 4493 4494 4495<div style="margin: auto;"> 4496 <h3 class="magick-header"><a id="green-primary"></a>-green-primary <var>x,y</var></h3> 4497</div> 4498 4499<p class="magick-description">green chromaticity primary point.</p> 4500 4501 4502<div style="margin: auto;"> 4503 <h3 class="magick-header"><a id="hald-clut"></a>-hald-clut</h3> 4504</div> 4505 4506<p class="magick-description">apply a Hald color lookup table to the image.</p> 4507 4508<p>A Hald color lookup table is a 3-dimensional color cube mapped to 2 4509dimensions. Create it with the <code>HALD:</code> prefix (e.g. HALD:8). You 4510can apply any color transformation to the Hald image and then use this option 4511to apply the transform to the image. </p> 4512 4513<pre> 4514convert image.png hald.png -hald-clut transform.png 4515</pre> 4516 4517<p>This option provides a convenient method for you to use Gimp or Photoshop 4518to make color corrections to the Hald CLUT image and subsequently apply them 4519to multiple images using an ImageMagick script. </p> 4520 4521<p>Note that the representation is only of the normal RGB color space and that 4522the whole color value triplet is used for the interpolated lookup of the 4523represented Hald color cube image. Because of this the operation is not <a 4524href="command-line-options.html#channel" >-channel</a> setting effected, nor can it adjust or modify an 4525images transparency or alpha/matte channel.</p> 4526 4527<p>See also <a href="command-line-options.html#clut" >-clut</a> which provides color value replacement 4528of the individual color channels, usually involving a simpler grayscale 4529image. E.g: grayscale to color replacement, or modification by a histogram 4530mapping. </p> 4531 4532 4533<div style="margin: auto;"> 4534 <h3 class="magick-header"><a id="help"></a>-help</h3> 4535</div> 4536 4537<p class="magick-description">print usage instructions.</p> 4538 4539<div style="margin: auto;"> 4540 <h3 class="magick-header"><a id="highlight-color"></a>-highlight-color <var>color</var></h3> 4541</div> 4542 4543<p class="magick-description">when comparing images, emphasize pixel differences with this color.</p> 4544 4545<div style="margin: auto;"> 4546 <h3 class="magick-header"><a id="hough-lines"></a>-hough-lines <var>width</var>x<var>height</var>{<var>+threshold</var>}</h3> 4547</div> 4548 4549<p class="magick-description">identify straight lines in the image (e.g. -hough-lines 9x9+195).</p> 4550 4551<p>Use the Hough line detector with any binary edge extracted image to locate and draw any straight lines that it finds.</p> 4552 4553<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>. 4554 4555<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> 4556 4557<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> 4558 4559<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> 4560 4561<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> 4562 4563<p>A text file listing the endpoints and counts may be created by using the suffix, .mvg, for the output image.</p> 4564 4565<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> 4566 4567<div style="margin: auto;"> 4568 <h3 class="magick-header"><a id="iconGeometry"></a>-iconGeometry <var>geometry</var></h3> 4569</div> 4570 4571<p class="magick-description">specify the icon geometry.</p> 4572 4573<p>Offsets, if present in the geometry specification, are handled in the same 4574manner as the <a href="command-line-options.html#geometry">-geometry</a> option, using X11 style to 4575handle negative offsets.</p> 4576 4577<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 4578 4579<div style="margin: auto;"> 4580 <h3 class="magick-header"><a id="iconic"></a>-iconic</h3> 4581</div> 4582 4583<p class="magick-description">start in icon mode in X Windows", 'animate', 'display</p> 4584 4585<div style="margin: auto;"> 4586 <h3 class="magick-header"><a id="identify"></a>-identify</h3> 4587</div> 4588 4589<p class="magick-description">identify the format and characteristics of the image.</p> 4590 4591<p>This information is printed: image scene number; image name; image size; 4592the image class (<var>DirectClass</var> or <var>PseudoClass</var>); the total number of unique colors; and the 4593number of seconds to read and transform the image. Refer to <a href="miff.html">MIFF</a> for 4594a description of the image class.</p> 4595 4596<p>If <a href="command-line-options.html#colors">-colors</a> is also specified, the total unique colors 4597in the image and color reduction error values are printed. Refer to <a 4598href="quantize.html">color 4599reduction algorithm</a> for a description of these values.</p> 4600 4601<p>If <a href="command-line-options.html#verbose">-verbose</a> precedes this option, copious 4602amounts of image properties are displayed including image statistics, profiles, 4603image histogram, and others.</p> 4604 4605<div style="margin: auto;"> 4606 <h3 class="magick-header"><a id="ift"></a>-ift</h3> 4607</div> 4608 4609<p class="magick-description">implements the inverse discrete Fourier transform (DFT).</p> 4610 4611<p>This option is new as of ImageMagick 6.5.4-3 (and now working for Windows 4612users in ImageMagick 6.6.0-9). It transforms a pair of magnitude and phase 4613images from the frequency domain to a single image in the normal or spatial 4614domain. See for example, <a 4615href="http://en.wikipedia.org/wiki/Fourier_transform">Fourier Transform</a>, 4616<a href="http://en.wikipedia.org/wiki/DFT">Discrete Fourier Transform</a> and 4617<a href="http://en.wikipedia.org/wiki/FFT">Fast Fourier Transform</a>.</p> 4618 4619<p>For example, depending upon the image format used to store the result of 4620the <a href="command-line-options.html#fft">-fft</a>, one would use either</p> 4621 4622<pre> 4623convert fft_image.miff -ift fft_image_ift.png 4624</pre> 4625 4626<p>or</p> 4627 4628<pre> 4629convert fft_image-0.png fft_image-1.png -ift fft_image_ift.png 4630</pre> 4631 4632<p>The resulting image may need to be cropped due to padding introduced when 4633the original image, prior to the <a href="command-line-options.html#fft">-fft</a> or <a 4634href="command-line-options.html#fft">+fft</a>, was not square or even dimensioned. Any padding is at 4635the right and/or bottom sides of the image.</p> 4636 4637<p>The <a href="http://www.fftw.org/">FFTW</a> delegate library is required to 4638use <a href="command-line-options.html#ift">-ift</a>.</p> 4639 4640<p>Use <a href="command-line-options.html#ift">+ift</a> (with HDRI enabled) to transform a pair of real 4641and imaginary images from the frequency domain to a single image in the normal 4642(spatial) domain.</p> 4643 4644<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> 4645 4646<div style="margin: auto;"> 4647 <h3 class="magick-header"><a id="immutable"></a>-immutable</h3> 4648</div> 4649 4650<p class="magick-description">make image immutable.</p> 4651 4652<div style="margin: auto;"> 4653 <h3 class="magick-header"><a id="implode"></a>-implode <var>factor</var></h3> 4654</div> 4655 4656<p class="magick-description">implode image pixels about the center.</p> 4657 4658<div style="margin: auto;"> 4659 <h3 class="magick-header"><a id="insert"></a>-insert <var>index</var></h3> 4660</div> 4661 4662<p class="magick-description">insert the last image into the image sequence.</p> 4663 4664<p>This option takes last image in the current image sequence and inserts it 4665at the given index. If a negative index is used, the insert position is 4666calculated before the last image is removed from the sequence. As such 4667<code>-insert -1</code> will result in no change to the image sequence.</p> 4668 4669<p>The <code>+insert</code> option is equivalent to <code>-insert -1</code>. In 4670other words, insert the last image, at the end of the current image sequence. 4671Consequently this has no effect on the image sequence order.</p> 4672 4673<div style="margin: auto;"> 4674 <h3 class="magick-header"><a id="intensity"></a>-intensity <var>method</var></h3> 4675</div> 4676 4677<p class="magick-description">method to generate intensity value from pixel.</p> 4678 4679<p>ImageMagick provides a number of methods used in situations where an 4680operator needs to determine a single grayscale value for some purpose, from 4681an image with red, green, and blue pixel components. Typically the linear 4682<code>Rec709Luminance</code> formula is used, which is the same formula used when 4683converting images to <code>-colorspace gray</code>. </p> 4684 4685<p>The following formulas are currently provided, and will first convert 4686the pixel values to linear-RGB or non-linear sRGB colorspace before 4687being applied to calculate the final greyscale value. </p> 4688 4689<dl class="dl-horizontal"> 4690<dt>Rec601Luma</dt><dd> 0.298839R' + 0.586811G'+ 0.114350B'</dd> 4691<dt>Rec601Luminance</dt><dd> 0.298839R + 0.586811G + 0.114350B</dd> 4692<dt>Rec709Luma</dt><dd> 0.212656R' + 0.715158G' + 0.072186B'</dd> 4693<dt>Rec709Luminance</dt><dd> 0.212656R + 0.715158G + 0.072186B</dd> 4694<dt>Brightness</dt><dd> max(R', G', B')</dd> 4695<dt>Lightness</dt><dd> (min(R', G', B') + max(R', G', B')) / 2.0</dd> 4696</dl> 4697 4698<p>Note that the above R,G,B values is the image's linear-RGB values, while 4699R',G',B' are sRGB non-linear values. </p> 4700 4701<p>These intensity methods are mathematical in nature and will use the 4702current value in the images respective R,G,B channel regardless of 4703what that is, or what colorspace the image is currently using.</p> 4704 4705<dl class="dl-horizontal"> 4706<dt>Average</dt><dd>(R + G + B) / 3.0</dd> 4707<dt>MS</dt><dd>(R^2 + G^2 + B^2) / 3.0</dd> 4708<dt>RMS</dt><dd>sqrt( (R^2 + G^2 + B^2) / 3.0 )</dd> 4709</dl> 4710 4711<p>These methods are often used for other purposes, such as generating a 4712grayscale difference image between two color images (using <a href="command-line-options.html#compose" 4713>-compose</a> '<code>Difference</code>' composition. </p> 4714 4715<p> For example The 'MS' (Mean Squared) setting is good for minimizing color 4716error comparisions. While... The method 'RMS' (Root Mean Squared) for 4717example is appropriate for calculating color vector distance, from a color 4718difference image. This is equivalent to the color only component of the <a 4719href="command-line-options.html#fuzz" >-fuzz</a> factor color compare setting. </p> 4720 4721<p>See also <a href="command-line-options.html#grayscale" >-grayscale</a> which applies one of the above 4722grayscaling formula directly to an image without setting the <a 4723href="command-line-options.html#intensity" >-intensity</a> setting.</p> 4724 4725<p>The <a href="command-line-options.html#colorspace" >-colorspace gray</a> image conversion also uses 4726the current intensity setting, but will always convert the image to the 4727appropriate sRGB or linear-RGB colorspace before appling the above 4728function.</p> 4729 4730<p>To print a complete list of possible pixel intensity setting methods, use <a href="command-line-options.html#list">-list intensity</a>.</p> 4731 4732<p>Operators affected by the <a href="command-line-options.html#intensity" >-intensity</a> setting include:</p> 4733 4734<pre> 4735-adaptive-blur 4736-adaptive-sharpen 4737-black-threshold 4738-clut (when mapping greyscale CLUT image to alpha channel if set by -channels) 4739-colors for gray colorspace 4740-compose {LightenIntensity, DarkenIntensity, CopyOpacity, CopyBlack} 4741-contrast-stretch 4742-distort {ErodeIntensity, DilateIntensity} 4743-normalize 4744-random-threshold 4745-selective-blur 4746-shade 4747-threshold 4748-tint 4749-white-threshold 4750</pre> 4751 4752<div style="margin: auto;"> 4753 <h3 class="magick-header"><a id="intent"></a>-intent <var>type</var></h3> 4754</div> 4755 4756<p class="magick-description">use this type of rendering intent when managing the image color.</p> 4757 4758<p>Use this option to affect the color management operation of an image (see 4759<a href="command-line-options.html#profile">-profile</a>). Choose from these intents: <code>Absolute, 4760Perceptual, Relative, Saturation</code>.</p> 4761 4762<p>The default intent is Perceptual for the sRGB colorspace and undefined for the RGB and gray colorspaces.</p> 4763 4764<p>To print a complete list of rendering intents, use <a href="command-line-options.html#list">-list intent</a>.</p> 4765 4766<div style="margin: auto;"> 4767 <h3 class="magick-header"><a id="interlace"></a>-interlace <var>type</var></h3> 4768</div> 4769 4770<p class="magick-description">the type of interlacing scheme.</p> 4771 4772<p>Choose from:</p> 4773 4774<pre> 4775none 4776line 4777plane 4778partition 4779JPEG 4780GIF 4781PNG 4782</pre> 4783 4784<p>This option is used to specify the type of interlacing scheme for raw image 4785formats such as <code>RGB</code> or <code>YUV</code>.</p> 4786 4787<p><code>None</code> means do not interlace (RGBRGBRGBRGBRGBRGB...),</p> 4788 4789<p><code>Line</code> uses scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...), and.</p> 4790 4791<p><code>Plane</code> uses plane interlacing (RRRRRR...GGGGGG...BBBBBB...).</p> 4792 4793<p><code>Partition</code> is like plane except the different planes are saved to 4794individual files (e.g. image.R, image.G, and image.B).</p> 4795 4796<p>Use <code>Line</code> or <code>Plane</code> to create an <code>interlaced 4797PNG</code> or <code>GIF</code> or <code>progressive JPEG</code> image.</p> 4798 4799<p>To print a complete list of interlacing schemes, use <a href="command-line-options.html#list">-list 4800interlace</a>.</p> 4801 4802<div style="margin: auto;"> 4803 <h3 class="magick-header"><a id="interpolate"></a>-interpolate <var>type</var></h3> 4804</div> 4805 4806<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> 4807 4808<p>When looking up the color of a pixel using a non-integer floating point 4809value, you typically fall in between the pixel colors defined by the source 4810image. This setting determines how the color is determined from the colors of 4811the pixels surrounding that point. That is how to determine the color of a 4812point that falls between two, or even four different colored pixels. </p> 4813 4814<dl class="dl-horizontal"> 4815 <dt>integer</dt> 4816 <dd>The color of the top-left pixel (floor function)</dd> 4817 <dt>nearest-neighbor</dt> 4818 <dd>The nearest pixel to the lookup point (rounded function)</dd> 4819 <dt>average</dt> 4820 <dd>The average color of the surrounding four pixels</dd> 4821 <dt>bilinear</dt> 4822 <dd>A double linear interpolation of pixels (the default)</dd> 4823 <dt>mesh</dt> 4824 <dd>Divide area into two flat triangular interpolations</dd> 4825 <dt>bicubic</dt> 4826 <dd>Fitted bicubic-spines of surrounding 16 pixels</dd> 4827 <dt>spline</dt> 4828 <dd>Direct spline curves (colors are blurred)</dd> 4829 <dt>filter</dt> 4830 <dd>Use resize <a href="command-line-options.html#filter">-filter</a> settings</dd> 4831</dl> 4832 4833<p>This most important for distortion operators such as <a href="command-line-options.html#distort" 4834>-distort</a>, <a href="command-line-options.html#implode" >-implode</a>, <a href="command-line-options.html#transform" 4835>-transform</a> and <a href="command-line-options.html#fx" >-fx</a>. </p> 4836 4837<p>To print a complete list of interpolation methods, use <a href="command-line-options.html#list">-list interpolate</a>.</p> 4838 4839<p>See also <a href="command-line-options.html#virtual-pixel" >-virtual-pixel</a>, for control of the 4840lookup for positions outside the boundaries of the image. </p> 4841 4842 4843<div style="margin: auto;"> 4844 <h3 class="magick-header"><a id="interline-spacing"></a>-interline-spacing <var>value</var></h3> 4845</div> 4846 4847<p class="magick-description">the space between two text lines.</p> 4848 4849<div style="margin: auto;"> 4850 <h3 class="magick-header"><a id="interword-spacing"></a>-interword-spacing <var>value</var></h3> 4851</div> 4852 4853<p class="magick-description">the space between two words.</p> 4854 4855<div style="margin: auto;"> 4856 <h3 class="magick-header"><a id="kerning"></a>-kerning <var>value</var></h3> 4857</div> 4858 4859<p class="magick-description">the space between two letters.</p> 4860 4861<div style="margin: auto;"> 4862 <h3 class="magick-header"><a id="kuwahara"></a>-kuwahara <var>radius</var><br />-kuwahara <var>radius</var>x<var>sigma</var></h3> 4863</div> 4864 4865<p class="magick-description">edge preserving noise reduction filter.</p> 4866 4867<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> 4868 4869 4870<div style="margin: auto;"> 4871 <h3 class="magick-header"><a id="label"></a>-label <var>name</var></h3> 4872</div> 4873 4874<p class="magick-description">assign a label to an image.</p> 4875 4876<p>Use this option to assign a specific label to the image, as it is read in 4877or created. You can use the <a href="command-line-options.html#set" >-set</a> operation to re-assign 4878a the labels of images already read in. Image formats such as TIFF, PNG, 4879MIFF, supports saving the label information with the image.</p> 4880 4881<p>When saving an image to a <var>PostScript</var> file, any label 4882assigned to an image is used as a header string to print above the postscript 4883image. </p> 4884 4885<p>You can include the image filename, type, width, height, or other image 4886attribute by embedding special format character. See <a href="escape.html">Format and Print Image 4887Properties</a> for details of the percent escape codes.</p> 4888 4889<p>For example,</p> 4890 4891<pre> 4892-label "%m:%f %wx%h" bird.miff 4893</pre> 4894 4895<p>assigns an image label of <code>MIFF:bird.miff 512x480</code> to the 4896"<code>bird.miff</code>" image and whose width is 512 and height is 480, as it 4897is read in. If a <a href="command-line-options.html#label">+label</a> option was used instead, any 4898existing label present in the image would be used. You can remove all labels 4899from an image by assigning the empty string. </p> 4900 4901<p>A label is not drawn on the image, but is embedded in the image datastream 4902via <var>Label</var> tag or similar mechanism. If you want the label to be 4903visible on the image itself, use the <a href="command-line-options.html#draw">-draw</a> option, or 4904during the final processing in the creation of an image montage.</p> 4905 4906<p>If the first character of <var>string</var> is <var>@</var>, the image label is read from a file titled by the 4907remaining characters in the string. Labels in a file are literal, no embedded 4908formatting characters are recognized.</p> 4909 4910 4911<div style="margin: auto;"> 4912 <h3 class="magick-header"><a id="lat"></a>-lat <var>width</var><br />-lat <var>width</var>x<var>height</var>{<var>+-</var>}<var>offset</var>{<var>%</var>}</h3> 4913</div> 4914 4915<p class="magick-description">perform local adaptive threshold.</p> 4916 4917<p>Adaptively threshold each pixel based on the value of pixels in a 4918surrounding window. If the current pixel is lighter than this average plus 4919the optional <code>offset</code>, then it is made white, otherwise it is made 4920black. Small variations in pixel values such as found in scanned documents 4921can be ignored if offset is positive. A negative offset will make it more 4922sensitive to those small variations. </p> 4923 4924<p>This is commonly used to threshold images with an uneven background. It is 4925based on the assumption that average color of the small window is the 4926the local background color, from which to separate the foreground color. </p> 4927 4928 4929<div style="margin: auto;"> 4930 <h3 class="magick-header"><a id="layers"></a>-layers <var>method</var></h3> 4931</div> 4932 4933<p class="magick-description">handle multiple images forming a set of image layers or animation frames.</p> 4934 4935<p>Perform various image operation methods to a ordered sequence of images 4936which may represent either a set of overlaid 'image layers', a GIF disposal 4937animation, or a fully-'coalesced' animation sequence. </p> 4938 4939<table class="table table-condensed table-striped"> 4940 <tbody> 4941 <tr> 4942 <th style="width: 8%">Method</th> 4943 <th>Description</th> 4944 </tr> 4945 4946 <tr> 4947 <td>compare-any</td> 4948 <td>Crop the second and later frames to the smallest rectangle 4949 that contains all the differences between the two images. No GIF <a 4950 href="command-line-options.html#dispose" >-dispose</a> methods are taken into account. </td> 4951 </tr> 4952 4953 <tr><td></td><td>This exactly the same as the <a href="command-line-options.html#deconstruct" 4954 >-deconstruct</a> operator, and does not preserve animations normal 4955 working, especially when animation used layer disposal methods such as 4956 '<code>Previous</code>' or '<code>Background</code>'. </td> 4957 </tr> 4958 4959 <tr> 4960 <td>compare-clear</td> 4961 <td>As '<code>compare-any</code>' but crop to the bounds of any 4962 opaque pixels which become transparent in the second frame. That is the 4963 smallest image needed to mask or erase pixels for the next frame. </td> 4964 </tr> 4965 4966 <tr> 4967 <td>compare-overlay</td> 4968 <td>As '<code>compare-any</code>' but crop to pixels that add 4969 extra color to the next image, as a result of overlaying color pixels. 4970 That is the smallest single overlaid image to add or change colors. </td> 4971 </tr> 4972 4973 <tr><td></td><td>This can be used with the <a href="command-line-options.html#compose" >-compose</a> alpha 4974 composition method '<code>change-mask</code>', to reduce the image to 4975 just the pixels that need to be overlaid. </td> 4976 </tr> 4977 4978 <tr> 4979 <td>coalesce</td> 4980 <td>Equivalent to a call to the <a href="command-line-options.html#coalesce" 4981 >-coalesce</a> operator. Apply the layer disposal methods set in the 4982 current image sequence to form a fully defined animation sequence, as 4983 it should be displayed. Effectively converting a GIF animation into a 4984 'film strip'-like animation. </td> 4985 </tr> 4986 4987 <tr> 4988 <td>composite</td> 4989 <td>Alpha Composition of two image lists, separated by a 4990 "<code>null:</code>" image, with the destination image list first, and 4991 the source images last. An image from each list are composited 4992 together until one list is finished. The separator image and source 4993 image lists are removed. </td> 4994 </tr> 4995 4996 4997 <tr><td></td> 4998 <td>The <a href="command-line-options.html#geometry" >-geometry</a> offset is adjusted according 4999 to <a href="command-line-options.html#gravity" >-gravity</a> in accordance of the virtual 5000 canvas size of the first image in each list. Unlike a normal <a 5001 href="command-line-options.html#composite" >-composite</a> operation, the canvas offset is also 5002 added to the final composite positioning of each image. </td> </tr> 5003 5004 <tr><td></td> 5005 <td>If one of the image lists only contains one image, that image is 5006 applied to all the images in the other image list, regardless of which 5007 list it is. In this case it is the image meta-data of the list which 5008 preserved. </td> 5009 </tr> 5010 5011 5012 <tr> 5013 <td>dispose</td> 5014 <td>This like '<code>coalesce</code>' but shows the look of 5015 the animation after the layer disposal method has been applied, before 5016 the next sub-frame image is overlaid. That is the 'dispose' image that 5017 results from the application of the GIF <a href="command-line-options.html#dispose" 5018 >-dispose</a> method. This allows you to check what 5019 is going wrong with a particular animation you may be developing. 5020 </td> 5021 </tr> 5022 5023 <tr> 5024 <td>flatten</td> 5025 <td>Create a canvas the size of the first images virtual 5026 canvas using the current <a href="command-line-options.html#background" >-background</a> color, 5027 and <a href="command-line-options.html#compose" >-compose</a> each image in turn onto that 5028 canvas. Images falling outside that canvas is clipped. Final 5029 image will have a zero virtual canvas offset. </td> 5030 </tr> 5031 5032 <tr><td></td> 5033 <td>This usually used as one of the final 'image layering' operations 5034 overlaying all the prepared image layers into a final image. </td> 5035 </tr> 5036 5037 <tr><td></td> 5038 <td>For a single image this method can also be used to fillout a virtual 5039 canvas with real pixels, or to underlay an opaque color to remove 5040 transparency from an image.</td> 5041 </tr> 5042 5043 5044 <tr> 5045 <td>merge</td> 5046 <td>As 'flatten' method but merging all the given image 5047 layers to create a new layer image just large enough to hold all the 5048 image without clipping or extra space. The new images virtual offset 5049 will preserve the position of the new layer, even if this offset is 5050 negative. The virtual canvas size of the first image is preserved. 5051 </td> 5052 </tr> 5053 5054 <tr><td></td><td>Caution is advised when handling image layers with 5055 negative offsets as few image file formats handle them correctly. 5056 Following this operation method with <a href="command-line-options.html#repage" >+repage</a> 5057 will remove the layer offset, and create an image in which all the 5058 overlaid image positions relative to each other is preserved, though 5059 not necessarily exactly where you specified them. 5060 </td> 5061 </tr> 5062 5063 <tr><td></td><td>See also 'trim-bounds' below which is closely related but 5064 without doing the'flatten' to merge the images together. </td> 5065 </tr> 5066 5067 <tr> 5068 <td>mosaic</td> 5069 <td>As 'flatten' method but expanding the initial canvas size 5070 of the first image in a positive direction only so as to hold all the 5071 image layers. However as a virtual canvas is 'locked' to the origin, 5072 by its own definition, image layers with a negative offsets will still 5073 become clipped by the top and left edges. See 'merge' or 'trim-bounds' 5074 if this could be a problem. </td> 5075 5076 </tr> 5077 5078 <tr><td></td><td>This method is commonly used to layout individual image 5079 using various offset but without knowing the final canvas size. The 5080 resulting image will, like 'flatten' not have any virtual offset, so 5081 can be saved to any image file format. </td> 5082 </tr> 5083 5084 5085 <tr> 5086 <td>optimize</td> 5087 <td>Optimize a coalesced animation, into GIF animation using 5088 a number of general techniques. This currently a short cut to 5089 apply both the '<code>optimize-frame</code>', and 5090 '<code>optimize-transparency</code>' methods but may be expanded to 5091 include other optimization methods as they are developed. </td> 5092 </tr> 5093 5094 <tr> 5095 <td>optimize-frame</td> 5096 <td>Optimize a coalesced animation, into GIF animation by 5097 reducing the number of pixels per frame as much as possible by 5098 attempting to pick the best layer disposal method to use, while ensuring 5099 the result will continue to animate properly. </td> 5100 </tr> 5101 5102 <tr><td></td><td> There is no guarantee that the best optimization is found. 5103 But then no reasonably fast GIF optimization algorithm can do this. 5104 However this does seem to do better than most other GIF frame 5105 optimizers seen. </td> 5106 </tr> 5107 5108 <tr> 5109 <td>optimize-plus</td> 5110 <td>As '<code>optimize-frame</code>' but attempt to improve the 5111 overall optimization by adding extra frames to the animation, without 5112 changing the final look or timing of the animation. The frames are 5113 added to attempt to separate the clearing of pixels from the 5114 overlaying of new additional pixels from one animation frame to the 5115 next. If this does not improve the optimization (for the next frame 5116 only), it will fall back to the results of the previous normal 5117 '<code>optimize-frame</code>' technique. </td> 5118 </tr> 5119 5120 <tr><td></td><td>There is the possibility that the change in the disposal 5121 style will result in a worsening in the optimization of later frames, 5122 though this is unlikely. In other words there no guarantee that it is 5123 better than the normal '<code>optimize-frame</code>' technique. For some 5124 animations however you can get a vast improvement in the final 5125 animation size. </td> 5126 </tr> 5127 5128 <tr> 5129 <td>optimize-transparency</td> 5130 <td>Given a GIF animation, replace any pixel in the sub-frame 5131 overlay images with transparency, if it does not change the resulting 5132 animation by more than the current <a href="command-line-options.html#fuzz" >-fuzz</a> factor. 5133 </td> 5134 </tr> 5135 5136 <tr><td></td><td>This should allow a existing frame optimized GIF animation 5137 to compress into a smaller file size due to larger areas of one 5138 (transparent) color rather than a pattern of multiple colors repeating 5139 the current disposed image of the last frame. </td> 5140 </tr> 5141 5142 <tr> 5143 <td>remove-dups</td> 5144 <td>Remove (and merge time delays) of duplicate consecutive 5145 images, so as to simplify layer overlays of coalesced animations. 5146 </td> 5147 </tr> 5148 5149 <tr><td></td><td>Usually this a result of using a constant time delay 5150 across the whole animation, or after a larger animation was split into 5151 smaller sub-animations. The duplicate frames could also have been 5152 used as part of some frame optimization methods. </td> 5153 </tr> 5154 5155 <tr> 5156 <td>remove-zero</td> 5157 <td>Remove any image with a zero time delay, unless ALL the 5158 images have a zero time delay (and is not a proper timed animation, a 5159 warning is then issued). </td> 5160 </tr> 5161 5162 <tr><td></td><td>In a GIF animation, such images are usually frames which 5163 provide partial intermediary updates between the frames that are 5164 actually displayed to users. These frames are usually added for 5165 improved frame optimization in GIF animations. </td> 5166 </tr> 5167 5168 <tr> 5169 <td>trim-bounds</td> 5170 <td>Find the bounds of all the images in the current 5171 image sequence, then adjust the offsets so all images are contained on 5172 a minimal positive canvas. None of the image data is modified or 5173 merged, only the individual image virtual canvas size and offset. 5174 All the images is given the same canvas size, and and will have 5175 a positive offset, but will remain in the same position relative to 5176 each other. As a result of the minimal canvas size at least one image 5177 will touch every edge of that canvas. The image data touching those 5178 edges however may be transparent. </td> 5179 </tr> 5180 5181 <tr><td></td><td>The result is much like if you used 'merge' followed by a 5182 <a href="command-line-options.html#repage" >+repage</a> option, except that all the images 5183 have been kept separate. If 'flatten' is used after using 5184 'trim-bounds' you will get the same result. </td> 5185 </tr> 5186 5187 </tbody> 5188</table> 5189 5190<p>To print a complete list of layer types, use <a href="command-line-options.html#list">-list layers</a>.</p> 5191 5192<p>The operators <a href="command-line-options.html#coalesce" >-coalesce</a>, <a href="command-line-options.html#deconstruct" 5193>-deconstruct</a>, <a href="command-line-options.html#flatten" >-flatten</a>, and <a href="command-line-options.html#mosaic" 5194>-mosaic</a> are only aliases for the above methods and may be depreciated in 5195the future. Also see <a href="command-line-options.html#page" >-page</a>, <a href="command-line-options.html#repage" 5196>-repage</a> operators, the <a href="command-line-options.html#compose" >-compose</a> setting, and the 5197GIF <a href="command-line-options.html#dispose" >-dispose</a> and <a href="command-line-options.html#delay" >-delay</a> 5198settings. </p> 5199 5200 5201<div style="margin: auto;"> 5202 <h3 class="magick-header"><a id="level"></a>-level <var>black_point</var>{,<var>white_point</var>}{<var>%</var>}{,<var>gamma</var>}</h3> 5203</div> 5204 5205<p class="magick-description">adjust the level of image channels.</p> 5206 5207<p>Given one, two or three values delimited with commas: black-point, 5208white-point, gamma (for example: 10,250,1.0 or 2%,98%,0.5). The black and 5209white points range from 0 to <var>QuantumRange</var>, or from 0 to 5210100%; if the white point is omitted it is set to (<var>QuantumRange</var> - black_point), so as to center contrast changes. 5211If a <code>%</code> sign is present anywhere in the string, both black and white 5212points are percentages of the full color range. Gamma will do a <a 5213href="command-line-options.html#gamma">-gamma</a> adjustment of the values. If it is omitted, the 5214default of 1.0 (no gamma correction) is assumed.</p> 5215 5216<p>In normal usage (<code>-level</code>) the image values are stretched so that 5217the given '<code>black_point</code>' value in the original image is set to zero 5218(or black), while the given '<code>white_point</code>' value is set to <var>QuantumRange</var> (or white). This provides you with direct 5219contrast adjustments to the image. The '<code>gamma</code>' of the resulting 5220image will then be adjusted. </p> 5221 5222<p>From ImageMagick v6.4.1-9 using the plus form of the operator 5223(<code>+level</code>) or adding the special '!' flag anywhere in the argument 5224list, will cause the operator to do the reverse of the level adjustment. That 5225is a zero, or <var>QuantumRange</var> value (black, and white, resp.) 5226in the original image, is adjusted to the given level values, allowing you to 5227de-contrast, or compress the channel values within the image. The 5228'<code>gamma</code>' is adjusted before the level adjustment to de-contrast the 5229image is made. </p> 5230 5231<p>Only the channels defined by the current <a href="command-line-options.html#channel">-channel</a> 5232setting are adjusted (defaults to RGB color channels only), allowing you to 5233limit the effect of this operator. </p> 5234 5235<p>Please note that the transparency channel is treated as 'matte' 5236values (0 is opaque) and not as 'alpha' values (0 is transparent).</p> 5237 5238 5239<div style="margin: auto;"> 5240 <h3 class="magick-header"><a id="level-colors"></a>-level-colors {<var>black_color</var>}{,}{<var>white_color</var>}</h3> 5241</div> 5242 5243<p class="magick-description">adjust the level of an image using the provided dash separated colors.</p> 5244 5245<p>This function is exactly like <a href="command-line-options.html#level">-level</a>, except that the 5246value value for each color channel is determined by the 5247'<code>black_color</code>' and '<code>white_color</code>' colors given (as 5248described under the <a href="command-line-options.html#fill">-fill</a> option). </p> 5249 5250<p>This effectually means the colors provided to <code>-level-colors</code> 5251is mapped to become 'black' and 'white' respectively, with all the other 5252colors linearly adjusted (or clipped) to match that change. Each channel is 5253adjusted separately using the channel values of the colors specified. </p> 5254 5255<p>On the other hand the plus form of the operator (<code>+level-colors</code>) 5256will map the image color 'black' and 'white' to the given colors 5257respectively, resulting in a gradient (de-contrasting) tint of the image to 5258those colors. This can also be used to convert a plain grayscale image into a 5259one using the gradient of colors specified. </p> 5260 5261<p>By supplying a single color with a comma separator either before or after 5262that color, will just replace the respective 'black' or 'white' point 5263respectively. But if no comma separator is provided, the given color is 5264used for both the black and white color points, making the operator either 5265threshold the images around that color (- form) or set all colors to that 5266color (+ form). </p> 5267 5268 5269<div style="margin: auto;"> 5270 <h3 class="magick-header"><a id="limit"></a>-limit <var>type value</var></h3> 5271</div> 5272 5273<p class="magick-description">Set the pixel cache resource limit.</p> 5274 5275<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> 5276 5277<p>The value for <code>file</code> is in number of files. The other limits are 5278in bytes. Define arguments for the memory, map, area, and disk resource limits 5279with SI prefixes (.e.g 100MB).</p> 5280 5281<p>By default the limits are 768 files, 3GB of image area, 1.5GiB memory, 3GiB 5282memory map, and 18.45EB of disk. These limits are adjusted relative to the 5283available resources on your computer if this information is available. When 5284any limit is reached, ImageMagick fails in some fashion but attempts to take 5285compensating actions, if possible. For example, the following limits 5286memory:</p> 5287 5288<pre> 5289-limit memory 32MiB -limit map 64MiB 5290</pre> 5291 5292<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> 5293 5294<pre> 5295-> identify -list resource 5296Resource limits: 5297 Width: 100MP 5298 Height: 100MP 5299 Area: 25.181GB 5300 Memory: 11.726GiB 5301 Map: 23.452GiB 5302 Disk: unlimited 5303 File: 768 5304 Thread: 12 5305 Throttle: 0 5306 Time: unlimited 5307</pre> 5308 5309<p>Requests for pixel storage to keep intermediate images are satisfied by one 5310of three resource categories: in-memory pool, memory-mapped files pool, and 5311disk pool (in that order) depending on the <a href="command-line-options.html#limit">‑limit</a> settings 5312and whether the system honors a resource request. If the total size of 5313allocated pixel storage in the given pool reaches the corresponding limit, the 5314request is passed to the next pool. Additionally, requests that exceed the 5315<code>area</code> limit automagically are allocated on disk.</p> 5316 5317<p>To illustrate how ImageMagick utilizes resource limits, consider a typical 5318image resource request. First, ImageMagick tries to allocate the pixels in 5319memory. The request might be denied if the resource request exceeds the 5320<code>memory</code> limit or if the system does not honor the request. If 5321a memory request is not honored, the pixels are allocated to disk and the file 5322is memory-mapped. However, if the allocation request exceeds the 5323<code>map</code> limit, the resource allocation goes to disk. In all cases, if 5324the resource request exceeds the <code>area</code> limit, the pixels are 5325automagically cached to disk. If the disk has a hard limit, the program 5326fails.</p> 5327 5328<p>In most cases you simply do not need to concern yourself with resource 5329limits. ImageMagick chooses reasonable defaults and most images do not tax 5330your computer resources. Where limits do come in handy is when you process 5331images that are large or on shared systems where ImageMagick can consume all 5332or most of the available memory. In this case, the ImageMagick workflow slows 5333other processes or, in extreme cases, brings the system to a halt. Under 5334these circumstances, setting limits give some assurances that the ImageMagick 5335workflow will not interfere with other concurrent uses of the computer. For 5336example, assume you have a web interface that processes images uploaded from 5337the Internet. To assure ImageMagick does not exceed 10MiB of memory you can 5338simply set the area limit to 10MiB:</p> 5339 5340<pre> 5341-limit area 10MB 5342</pre> 5343 5344<p>Now whenever a large image is processed, the pixels are automagically 5345cached to disk instead of memory. This of course implies that large images 5346typically process very slowly, simply because pixel processing in memory can 5347be an order of magnitude faster than on disk. Because your web site users 5348might inadvertently upload a huge image to process, you should set a disk 5349limit as well:</p> 5350 5351<pre> 5352-limit area 10MB -limit disk 500MB 5353</pre> 5354 5355<p>Here ImageMagick stops processing if an image requires more than 500MB of disk storage.</p> 5356 5357<p>In addition to command-line resource limit option, resources can be set 5358with <a href="resources.html#environment" >environment variables</a>. Set the 5359environment variables <code>MAGICK_AREA_LIMIT</code>, 5360<code>MAGICK_DISK_LIMIT</code>, <code>MAGICK_FILE_LIMIT</code>, 5361<code>MAGICK_MEMORY_LIMIT</code>, <code>MAGICK_MAP_LIMIT</code>, 5362<code>MAGICK_THREAD_LIMIT</code>, <code>MAGICK_TIME_LIMIT</code> for limits of 5363image area, disk space, open files, heap memory, memory map, number of threads 5364of execution, and maximum elapsed time in seconds respectively.</p> 5365 5366<p> Inquisitive users can try adding <a href="command-line-options.html#debug">-debug cache</a> to 5367their commands and then scouring the generated output for references to the 5368pixel cache, in order to determine how the pixel cache was allocated and how 5369resources were consumed. Advanced Unix/Linux users can pipe that output 5370through <code>grep memory|open|destroy|disk</code> for more readable sifting. 5371</p> 5372 5373<p>For more about ImageMagick's use of resources, see the section <b>Cache 5374Storage and Resource Requirements</b> on the <a href="architecture.html#cache 5375">Architecture</a> page. </p> 5376 5377<div style="margin: auto;"> 5378 <h3 class="magick-header"><a 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> 5379</div> 5380 5381<p class="magick-description">Linear with saturation stretch.</p> 5382 5383<p>This is very similar to <a href="command-line-options.html#contrast-stretch" >-contrast-stretch</a>, 5384and uses a 'histogram bin' to determine the range of color values that needs to 5385be stretched. However it then stretches those colors using the <a 5386href="command-line-options.html#level" >-level</a> operator.</p> 5387 5388<p>As such while the initial determination may have 'binning' round off 5389effects, the image colors are stretched mathematically, rather than using the 5390histogram bins. This makes the operator more accurate. </p> 5391 5392<p>note however that a <a href="command-line-options.html#linear-stretch" >-linear-stretch</a> of 5393'<code>0</code>' does nothing, while a value of '<code>1</code>' does a near 5394perfect stretch of the color range. </p> 5395 5396<p>See also <a href="command-line-options.html#auto-level" >-auto-level</a> for a 'perfect' 5397normalization of mathematical images. </p> 5398 5399<p>This operator is under review for re-development. </p> 5400 5401 5402<div style="margin: auto;"> 5403 <h3 class="magick-header"><a id="linewidth"></a>-linewidth</h3> 5404</div> 5405 5406<p class="magick-description">the line width for subsequent draw operations.</p> 5407 5408<div style="margin: auto;"> 5409 <h3 class="magick-header"><a id="liquid-rescale"></a>-liquid-rescale <var>geometry</var></h3> 5410</div> 5411 5412<p class="magick-description">rescale image with seam-carving.</p> 5413 5414<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 5415 5416<div style="margin: auto;"> 5417 <h3 class="magick-header"><a id="list"></a>-list <var>type</var></h3> 5418</div> 5419 5420<p class="magick-description">Print a list of supported arguments for various options or settings. Choose from these list types:</p> 5421 5422<pre class="pre-scrollable"> 5423Align 5424Alpha 5425Boolean 5426Cache 5427Channel 5428Class 5429ClipPath 5430Coder 5431Color 5432Colorspace 5433Command 5434Complex 5435Compose 5436Compress 5437Configure 5438DataType 5439Debug 5440Decoration 5441Delegate 5442Direction 5443Dispose 5444Distort 5445Dither 5446Endian 5447Evaluate 5448FillRule 5449Filter 5450Font 5451Format 5452Function 5453Gravity 5454Intensity 5455Intent 5456Interlace 5457Interpolate 5458Kernel 5459Layers 5460LineCap 5461LineJoin 5462List 5463Locale 5464LogEvent 5465Log 5466Magic 5467Method 5468Metric 5469Mime 5470Mode 5471Morphology 5472Module 5473Noise 5474Orientation 5475PixelIntensity 5476Policy 5477PolicyDomain 5478PolicyRights 5479Preview 5480Primitive 5481QuantumFormat 5482Resource 5483SparseColor 5484Statistic 5485Storage 5486Stretch 5487Style 5488Threshold 5489Type 5490Units 5491Validate 5492VirtualPixel 5493</pre> 5494 5495<p>These lists vary depending on your version of ImageMagick. Use "<code>-list 5496list</code>" to get a complete listing of all the "<code>-list</code>" arguments 5497available:</p> 5498 5499<pre> 5500identify -list list 5501</pre> 5502 5503<div style="margin: auto;"> 5504 <h3 class="magick-header"><a id="log"></a>-log <var>string</var></h3> 5505</div> 5506 5507<p class="magick-description">Specify format for debug log.</p> 5508 5509<p>This option specifies the format for the log printed when the <a 5510href="command-line-options.html#debug">-debug</a> option is active.</p> 5511 5512<p>You can display the following components by embedding special format 5513characters:</p> 5514 5515<dl class="dl-horizontal"> 5516<dt>%d</dt><dd>domain</dd> 5517<dt>%e</dt><dd>event</dd> 5518<dt>%f</dt><dd>function</dd> 5519<dt>%l</dt><dd>line</dd> 5520<dt>%m</dt><dd>module</dd> 5521<dt>%p</dt><dd>process ID</dd> 5522<dt>%r</dt><dd>real CPU time</dd> 5523<dt>%t</dt><dd>wall clock time</dd> 5524<dt>%u</dt><dd>user CPU time</dd> 5525<dt>%%</dt><dd>percent sign</dd> 5526<dt>\n</dt><dd>newline</dd> 5527<dt>\r</dt><dd>carriage return</dd> 5528</dl> 5529 5530<p>For example:</p> 5531 5532<pre> 5533convert -debug coders -log "%u %m:%l %e" in.gif out.png 5534</pre> 5535 5536<p>The default behavior is to print all of the components.</p> 5537 5538<div style="margin: auto;"> 5539 <h3 class="magick-header"><a id="loop"></a>-loop <var>iterations</var></h3> 5540</div> 5541 5542<p class="magick-description">add Netscape loop extension to your GIF animation.</p> 5543 5544<p>Set iterations to zero to repeat the animation an infinite number of times, 5545otherwise the animation repeats itself up to <var>iterations</var> 5546times.</p> 5547 5548<div style="margin: auto;"> 5549 <h3 class="magick-header"><a id="lowlight-color"></a>-lowlight-color <var>color</var></h3> 5550</div> 5551 5552<p class="magick-description">when comparing images, de-emphasize pixel differences with this color.</p> 5553 5554<div style="margin: auto;"> 5555 <h3 class="magick-header"><a id="magnify"></a>-magnify</h3> 5556</div> 5557 5558<p class="magick-description">double the size of the image with pixel art scaling.</p> 5559 5560 5561<div style="margin: auto;"> 5562 <h3 class="magick-header"><a id="map"></a>-map <var>type</var></h3> 5563</div> 5564 5565<p class="magick-description">Display image using this <var>type</var>.</p> 5566 5567<p>Choose from these <var>Standard Colormap</var> types:</p> 5568 5569<pre> 5570best 5571default 5572gray 5573red 5574green 5575blue 5576</pre> 5577 5578<p>The <var>X server</var> must support the <var>Standard 5579Colormap</var> you choose, otherwise an error occurs. Use <code>list</code> as 5580the type and <code>display</code> searches the list of colormap types in 5581<code>top-to-bottom</code> order until one is located. See <var>xstdcmap(1)</var> for one way of creating Standard Colormaps.</p> 5582 5583 5584<div style="margin: auto;"> 5585 <h3 class="magick-header"><a id="map_stream_"></a>-map <var>components</var></h3> 5586</div> 5587 5588<p class="magick-description">pixel map.</p> 5589 5590<p>Here are the valid components of a map:</p> 5591 5592<dl class="dl-horizontal"> 5593<dt>r</dt><dd> red pixel component</dd> 5594<dt>g</dt><dd> green pixel component</dd> 5595<dt>b</dt><dd> blue pixel component</dd> 5596<dt>a</dt><dd> alpha pixel component (0 is transparent)</dd> 5597<dt>o</dt><dd> opacity pixel component (0 is opaque)</dd> 5598<dt>i</dt><dd> grayscale intensity pixel component</dd> 5599<dt>c</dt><dd> cyan pixel component</dd> 5600<dt>m</dt><dd> magenta pixel component</dd> 5601<dt>y</dt><dd> yellow pixel component</dd> 5602<dt>k</dt><dd> black pixel component</dd> 5603<dt>p</dt><dd> pad component (always 0)</dd> 5604</dl> 5605 5606<p>You can specify as many of these components as needed in any order (e.g. 5607bgr). The components can repeat as well (e.g. rgbr).</p> 5608 5609 5610<div style="margin: auto;"> 5611 <h3 class="magick-header"><a id="mask"></a>-mask 5612<var>filename</var></h3> 5613</div> 5614 5615<p class="magick-description">Prevent updates to image pixels specified by the mask.</p> 5616 5617<p>This the same as using a mask used for composite masking operations, with 5618grayscale values causing blended updates of the image the mask is attached to. 5619</p> 5620 5621<p>Use <a href="command-line-options.html#mask">+mask</a> to remove the mask from images.</p> 5622 5623<p>Also see <a href="command-line-options.html#clip-mask">-clip-mask</a> which work in the same way, 5624but with strict boolean masking. </p> 5625 5626<div style="margin: auto;"> 5627 <h3 class="magick-header"><a id="mattecolor"></a>-mattecolor <var>color</var></h3> 5628</div> 5629 5630<p class="magick-description">Specify the color to be used with the <a href="command-line-options.html#frame">-frame</a> option.</p> 5631 5632<p>The color is specified using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p> 5633 5634<p>The default matte color is <code>#BDBDBD</code>, <span 5635style="background-color: #bdbdbd;">this shade of gray</span>.</p> 5636 5637<p>This is an IMv6 option, use <a href="command-line-options.html#alpha-color">-alpha-color</a> with IMv7.</p> 5638 5639<div style="margin: auto;"> 5640 <h3 class="magick-header"><a id="maximum"></a>-maximum</h3> 5641</div> 5642 5643<p class="magick-description">return the maximum intensity of an image sequence.</p> 5644 5645<p>Select the 'maximum' value from all the surrounding pixels. </p> 5646 5647<p>This is legacy option from the <a href="command-line-options.html#statistic" >method</a> of the same 5648name. </p> 5649 5650<div style="margin: auto;"> 5651 <h3 class="magick-header"><a id="median"></a>-median <var>geometry</var></h3> 5652</div> 5653 5654<p class="magick-description">apply a median filter to the image.</p> 5655 5656<p>Select the 'middle' value from all the surrounding pixels. </p> 5657 5658<p>This is legacy option from the <a href="command-line-options.html#statistic" >method</a> of the same 5659name. </p> 5660 5661<div style="margin: auto;"> 5662 <h3 class="magick-header"><a id="mean-shift"></a>-mean-shift <var>width</var>x<var>height</var>{<var>+distance</var>{%}</h3> 5663</div> 5664 5665<p class="magick-description">image noise removal and color reduction/segmentation (e.g. -mean-shift 7x7+10%).</p> 5666 5667<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> 5668 5669<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> 5670 5671<div style="margin: auto;"> 5672 <h3 class="magick-header"><a id="metric"></a>-metric <var>type</var></h3> 5673</div> 5674 5675<p class="magick-description">Output to STDERR a measure of the differences between images according to the <var>type</var> given metric.</p> 5676 5677<p>Choose from:</p> 5678 5679<dl class="dl-horizontal"> 5680<dt>AE</dt><dd> absolute error count, number of different pixels (-fuzz effected)</dd> 5681<dt>FUZZ</dt><dd> mean color distance</dd> 5682<dt>MAE</dt><dd> mean absolute error (normalized), average channel error distance</dd> 5683<dt>MEPP</dt><dd> mean error per pixel (normalized mean error, normalized peak error)</dd> 5684<dt>MSE</dt><dd> mean error squared, average of the channel error squared</dd> 5685<dt>NCC</dt><dd> normalized cross correlation</dd> 5686<dt>PAE</dt><dd> peak absolute (normalized peak absolute)</dd> 5687<dt>PHASH</dt><dd> perceptual hash</dd> 5688<dt>PSNR</dt><dd> peak signal to noise ratio</dd> 5689<dt>RMSE</dt><dd> root mean squared (normalized root mean squared)</dd> 5690</dl> 5691 5692<p>Control the '<code>AE</code>', or absolute count of pixels that are different, 5693with the <a href="command-line-options.html#fuzz" >-fuzz</a> factor (ignore pixels which 5694only changed by a small amount). Use '<code>PAE</code>' to find the 5695size of the <a href="command-line-options.html#fuzz" >-fuzz</a> factor needed to make all pixels 5696'similar', while '<code>MAE</code>' determines the factor needed 5697for about half the pixels to be similar. </p> 5698 5699<p>The '<code>MEPP</code>' metric returns three different metrics 5700('<code>MAE</code>', '<code>MAE</code>' normalized, and '<code>PAE</code>' 5701normalized) from a single comparison run. </p> 5702 5703<p>To print a complete list of metrics, use the <a href="command-line-options.html#list">-list 5704metric</a> option.</p> 5705 5706 5707<div style="margin: auto;"> 5708 <h3 class="magick-header"><a id="minimum"></a>-minimum</h3> 5709</div> 5710 5711<p class="magick-description">return the minimum intensity of an image sequence.</p> 5712 5713<p>Select the 'minimal' value from all the surrounding pixels. </p> 5714 5715<p>This is legacy option from the <a href="command-line-options.html#statistic" >method</a> of the same 5716name. </p> 5717 5718 5719 5720<div style="margin: auto;"> 5721 <h3 class="magick-header"><a id="mode"></a>-mode <var>geometry</var></h3> 5722</div> 5723 5724<p class="magick-description">make each pixel the \'predominant color\' of the neighborhood.'</p> 5725 5726<div style="margin: auto;"> 5727 <h3 class="magick-header">-mode <var>value</var></h3> 5728</div> 5729 5730<p class="magick-description">Mode of operation.</p> 5731 5732<p>Choose the <var>value</var> from these styles: <code>Frame, 5733Unframe, or Concatenate</code></p> 5734 5735<p>Use the <a href="command-line-options.html#list" >-list</a> option with a '<code>Mode</code>' argument 5736for a list of <a href="command-line-options.html#mode" >-mode</a> arguments available in your 5737ImageMagick installation.</p> 5738 5739 5740<div style="margin: auto;"> 5741 <h3 class="magick-header"><a id="modulate"></a>-modulate <var>brightness</var>[,<var>saturation</var>,<var>hue</var>]</h3> 5742</div> 5743 5744<p class="magick-description">Vary the <var>brightness</var>, <var>saturation</var>, and <var>hue</var> of an image.</p> 5745 5746<p>The arguments are given as a percentages of variation. A value of 100 means 5747no change, and any missing values are taken to mean 100.</p> 5748 5749<p>The <var>brightness</var> is a multiplier of the overall 5750brightness of the image, so 0 means pure black, 50 is half as bright, 200 is 5751twice as bright. To invert its meaning <a href="command-line-options.html#negate">-negate</a> the image 5752before and after. </p> 5753 5754<p>The <var>saturation</var> controls the amount of color in an 5755image. For example, 0 produce a grayscale image, while a large value such as 5756200 produce a very colorful, 'cartoonish' color.</p> 5757 5758<p>The <var>hue</var> argument causes a "rotation" of the colors 5759within the image by the amount specified. For example, 50 results in 5760a counter-clockwise rotation of 90, mapping red shades to purple, and so on. 5761A value of either 0 or 200 results in a complete 180 degree rotation of the 5762image. Using a value of 300 is a 360 degree rotation resulting in no change to 5763the original image. </p> 5764 5765<p>For example, to increase the color brightness by 20% and decrease the color 5766saturation by 10% and leave the hue unchanged, use <a 5767href="command-line-options.html#modulate">-modulate 120,90</a>.</p> 5768 5769<p>Use <a href="command-line-options.html#set">-set</a> attribute of '<code 5770>option:modulate:colorspace</code>' to specify which colorspace to 5771modulate. 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> 5772 5773<pre> 5774convert image.png -set option:modulate:colorspace hsb -modulate 120,90 modulate.png 5775</pre> 5776 5777<div style="margin: auto;"> 5778 <h3 class="magick-header"><a id="moments"></a>-moments</h3> 5779</div> 5780 5781<p class="magick-description">report image moments and perceptual hash.</p> 5782 5783 5784<div style="margin: auto;"> 5785 <h3 class="magick-header"><a id="monitor"></a>-monitor</h3> 5786</div> 5787 5788<p class="magick-description">monitor progress.</p> 5789 5790 5791<div style="margin: auto;"> 5792 <h3 class="magick-header"><a id="monochrome"></a>-monochrome</h3> 5793</div> 5794 5795<p class="magick-description">transform the image to black and white.</p> 5796 5797<div style="margin: auto;"> 5798 <h3 class="magick-header"><a id="morph"></a>-morph <var>frames</var></h3> 5799</div> 5800 5801<p class="magick-description">morphs an image sequence.</p> 5802 5803<p>Both the image pixels and size are linearly interpolated to give the 5804appearance of a metamorphosis from one image to the next, over all the images 5805in the current image list. The added images are the equivalent of a <a 5806href="command-line-options.html#blend">-blend</a> composition. The <var>frames</var> 5807argument determine how many images to interpolate between each image. </p> 5808 5809 5810<div style="margin: auto;"> 5811 <h3 class="magick-header"><a id="morphology"></a>-morphology</h3> 5812 <h3 class="magick-header">-morphology <var>method</var> <var>kernel</var></h3> 5813</div> 5814 5815<p class="magick-description">apply a morphology method to the image.</p> 5816 5817<p>Until I get around to writing an option summary for this, see <a 5818href="http://www.imagemagick.org/Usage/morphology/" >IM Usage Examples, 5819Morphology</a>. </p> 5820 5821 5822<div style="margin: auto;"> 5823 <h3 class="magick-header"><a id="mosaic"></a>-mosaic</h3> 5824</div> 5825 5826<p class="magick-description">an simple alias for the <a href="command-line-options.html#layers" >-layers</a> method "mosaic"</p> 5827 5828 5829<div style="margin: auto;"> 5830 <h3 class="magick-header"><a id="motion-blur"></a>-motion-blur <var>radius</var><br />-motion-blur <var>radius</var>x<var>sigma</var>+<var>angle</var></h3> 5831</div> 5832 5833<p class="magick-description">simulate motion blur.</p> 5834 5835<p>Blur with the given radius, standard deviation (sigma), and angle. The 5836angle given is the angle toward which the image is blurred. That is the 5837direction people would consider the object is coming from. </p> 5838 5839<p>Note that the blur is not uniform distribution, giving the motion a 5840definite sense of direction of movement. </p> 5841 5842<p>The <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting will determine how 5843pixels which are outside the image proper are blurred into the final result. 5844</p> 5845 5846<div style="margin: auto;"> 5847 <h3 class="magick-header"><a id="name"></a>-name</h3> 5848</div> 5849 5850<p class="magick-description">name an image.</p> 5851<div style="margin: auto;"> 5852 <h3 class="magick-header"><a id="negate"></a>-negate</h3> 5853</div> 5854 5855<p class="magick-description">replace each pixel with its complementary color.</p> 5856 5857<p>The red, green, and blue intensities of an image are negated. White becomes 5858black, yellow becomes blue, etc. Use <a href="command-line-options.html#negate">+negate</a> to only 5859negate the grayscale pixels of the image.</p> 5860 5861<div style="margin: auto;"> 5862 <h3 class="magick-header"><a id="noise"></a>-noise <var>geometry</var><br/> 5863 +noise <var>type</var></h3> 5864</div> 5865 5866<p class="magick-description">Add or reduce noise in an image.</p> 5867 5868<p>The principal function of noise peak elimination filter is to smooth the 5869objects within an image without losing edge information and without creating 5870undesired structures. The central idea of the algorithm is to replace a pixel 5871with its next neighbor in value within a pixel window, if this pixel has been 5872found to be noise. A pixel is defined as noise if and only if this pixel is 5873a maximum or minimum within the pixel window.</p> 5874 5875<p>Use <code><a href="command-line-options.html#noise">-noise</a> <var>radius</var></code> to 5876specify the width of the neighborhood when reducing noise. This is equivalent 5877to using a <code><a href="command-line-options.html#statistic" >-statistic</a> NonPeak</code> operation, 5878which should be used in preference.</p> 5879 5880<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 5881types:</p> 5882 5883<pre> 5884Gaussian 5885Impulse 5886Laplacian 5887Multiplicative 5888Poisson 5889Random 5890Uniform 5891</pre> 5892 5893<p>The amount of noise added can be controlled by the <code><a 5894href="command-line-options.html#attenuate" >-attenuate</a></code> setting. If unset the value is 5895equivalent to 1.0, or a maximum noise addition.</p> 5896 5897<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> 5898 5899<p>To print a complete list of noises, use the <a href="command-line-options.html#list">-list noise</a> option.</p> 5900 5901<p>Also see the <a href="command-line-options.html#evaluate">-evaluate</a> noise functions that allows 5902the use of a controlling value to specify the amount of noise that should be 5903added to an image. </p> 5904 5905 5906<div style="margin: auto;"> 5907 <h3 class="magick-header"><a id="normalize"></a>-normalize</h3> 5908</div> 5909 5910<p class="magick-description">Increase the contrast in an image by <var>stretching</var> the range of intensity values.</p> 5911 5912<p>The intensity values are stretched to cover the entire range of possible 5913values. While doing so, black-out at most <var>2%</var> of the pixels and 5914white-out at most <var>1%</var> of the pixels.</p> 5915 5916<p>Note that as of ImageMagick 6.4.7-0, <a href="command-line-options.html#normalize" >-normalize</a> 5917is equivalent to <a href="command-line-options.html#contrast-stretch" >-contrast-stretch 2%x1%</a>. 5918(Before this version, it was equivalent to <a href="command-line-options.html#contrast-stretch" 5919>-contrast-stretch 2%x99%</a>).</p> 5920 5921<p>All the channels are normalized in concert by the same amount so as to 5922preserve color integrity, when the default <a href="command-line-options.html#channel" >+channel</a> 5923setting is in use. Specifying any other <a href="command-line-options.html#channel" >-channel</a> 5924setting will normalize the RGB channels independently.</p> 5925 5926<p>See <a href="command-line-options.html#contrast-stretch" >-contrast-stretch</a> for more details. 5927Also see <a href="command-line-options.html#auto-level" >-auto-level</a> for a 'perfect' normalization 5928that is better suited to mathematically generated images. </p> 5929 5930<p>This operator is under review for re-development. </p> 5931 5932 5933<div style="margin: auto;"> 5934 <h3 class="magick-header"><a id="opaque"></a>-opaque <var>color</var></h3> 5935</div> 5936 5937<p class="magick-description">change this color to the fill color within the image.</p> 5938 5939<p>The <var>color</var> argument is defined using the format 5940described under the <a href="command-line-options.html#fill" >-fill</a> option. The <a href="command-line-options.html#fuzz" 5941>-fuzz</a> setting can be used to match and replace colors similar to the one 5942given.</p> 5943 5944<p>Use <a href="command-line-options.html#opaque">+opaque</a> to paint any pixel that does not match 5945the target color. </p> 5946 5947<p>The <a href="command-line-options.html#transparent">-transparent</a> operator is exactly the same 5948as <a href="command-line-options.html#opaque" >-opaque</a> but replaces the matching color with 5949transparency rather than the current <a href="command-line-options.html#fill">-fill</a> color setting. 5950To ensure that it can do this it also ensures that the image has an alpha 5951channel enabled, as per "<code><a href="command-line-options.html#alpha" >-alpha</a> set</code>", for 5952the new transparent colors, and does not require you to modify the <a 5953href="command-line-options.html#channel">-channel</a> to enable alpha channel handling. </p> 5954 5955 5956<div style="margin: auto;"> 5957 <h3 class="magick-header"><a id="ordered-dither"></a>-ordered-dither <var>threshold_map</var>{,<var>level</var>...}</h3> 5958</div> 5959 5960<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 5961given number of <var>levels</var> per color channel.</p> 5962 5963<p>You can choose from these standard threshold maps:</p> 5964 5965<pre class="pre-scrollable"> 5966threshold 1x1 Threshold 1x1 (non-dither) 5967checks 2x1 Checkerboard 2x1 (dither) 5968o2x2 2x2 Ordered 2x2 (dispersed) 5969o3x3 3x3 Ordered 3x3 (dispersed) 5970o4x4 4x4 Ordered 4x4 (dispersed) 5971o8x8 8x8 Ordered 8x8 (dispersed) 5972h3x4a 4x1 Halftone 4x4 (angled) 5973h6x6a 6x1 Halftone 6x6 (angled) 5974h8x8a 8x1 Halftone 8x8 (angled) 5975h3x4o Halftone 4x4 (orthogonal) 5976h6x6o Halftone 6x6 (orthogonal) 5977h8x8o Halftone 8x8 (orthogonal) 5978h36x16o Halftone 16x16 (orthogonal) 5979c5x5b c5x5 Circles 5x5 (black) 5980c5x5w Circles 5x5 (white) 5981c6x6b c6x6 Circles 6x6 (black) 5982c6x6w Circles 6x6 (white) 5983c7x7b c7x7 Circles 7x7 (black) 5984c7x7w Circles 7x7 (white) 5985</pre> 5986 5987<p> The <code>threshold</code> generated a simple 50% threshold of the image. 5988This could be used with <var >level</var> to do the equivalent of <a 5989href="command-line-options.html#posterize" >-posterize</a> to reduce an image to basic primary colors. 5990</p> 5991 5992<p>The <code>checks</code> pattern produces a 3 level checkerboard dither 5993pattern. That is a grayscale will become a pattern of solid black, solid 5994white, and mid-tone colors into a checkerboard pattern of black and white. 5995</p> 5996 5997<p>You can define your own <var >threshold map</var> for ordered 5998dithering and halftoning your images, in either personal or system 5999<code>thresholds.xml</code> XML file. See <a href="resources.html" >Resources</a> 6000for more details of configuration files. </p> 6001 6002<p>To print a complete list of the thresholds that have been defined, use the 6003<a href="command-line-options.html#list" >-list threshold</a> option.</p> 6004 6005<p>Note that at this time the same threshold dithering map is used for all 6006color channels, no attempt is made to offset or rotate the map for different 6007channels is made, to create an offset printing effect. Also as the maps are 6008simple threshold levels, the halftone and circle maps will create incomplete 6009circles along the edges of a colored area. Also all the effects are purely 6010on/off boolean effects, without anti-aliasing to make the circles smooth 6011looking. Large dots can be made to look better with a small amount of blurring 6012after being created. </p> 6013 6014 6015<div style="margin: auto;"> 6016 <h3 class="magick-header"><a id="orient"></a>-orient <var>image orientation</var></h3> 6017</div> 6018 6019<p class="magick-description">specify orientation of a digital camera image.</p> 6020 6021<p>Choose from these orientations:</p> 6022 6023<pre> 6024bottom-left right-top 6025bottom-right top-left 6026left-bottom top-right 6027left-top undefined 6028right-bottom 6029</pre> 6030 6031<p>To print a complete list of orientations, use the <a href="command-line-options.html#list" >-list 6032orientation</a> option.</p> 6033 6034 6035<div style="margin: auto;"> 6036 <h3 class="magick-header"><a id="page"></a>-page <var>geometry</var><br/> 6037 -page <var>media</var>[<var>offset</var>][{<var>^!<></var>}]<br/> 6038 +page 6039 </h3> 6040</div> 6041 6042<p class="magick-description">Set the size and location of an image on the larger virtual canvas.</p> 6043 6044<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 6045 6046<p>For convenience you can specify the page size using <var>media</var> (see below). Offsets can then be added as with other 6047<var>geometry</var> arguments (e.g. <a 6048href="command-line-options.html#page">-page</a> <code>Letter+43+43</code>).</p> 6049 6050<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. 6051The choices for a PostScript page are:</p> 6052 6053<dl class="dl-horizontal"> 6054<dt> 11x17 </dt> <dd> 792 x 1224</dd> 6055<dt> Ledger </dt> <dd> 1224 x 792</dd> 6056<dt> Legal </dt> <dd> 612 x 1008</dd> 6057<dt> Letter </dt> <dd> 612 x 792</dd> 6058<dt> LetterSmall</dt> <dd> 612 x 792</dd> 6059<dt> ArchE </dt> <dd> 2592 x 3456</dd> 6060<dt> ArchD </dt> <dd> 1728 x 2592</dd> 6061<dt> ArchC </dt> <dd> 1296 x 1728</dd> 6062<dt> ArchB </dt> <dd> 864 x 1296</dd> 6063<dt> ArchA </dt> <dd> 648 x 864</dd> 6064<dt> A0 </dt> <dd> 2380 x 3368</dd> 6065<dt> A1 </dt> <dd> 1684 x 2380</dd> 6066<dt> A2 </dt> <dd> 1190 x 1684</dd> 6067<dt> A3 </dt> <dd> 842 x 1190</dd> 6068<dt> A4 </dt> <dd> 595 x 842</dd> 6069<dt> A4Small </dt> <dd> 595 x 842</dd> 6070<dt> A5 </dt> <dd> 421 x 595</dd> 6071<dt> A6 </dt> <dd> 297 x 421</dd> 6072<dt> A7 </dt> <dd> 210 x 297</dd> 6073<dt> A8 </dt> <dd> 148 x 210</dd> 6074<dt> A9 </dt> <dd> 105 x 148</dd> 6075<dt> A10 </dt> <dd> 74 x 105</dd> 6076<dt> B0 </dt> <dd> 2836 x 4008</dd> 6077<dt> B1 </dt> <dd> 2004 x 2836</dd> 6078<dt> B2 </dt> <dd> 1418 x 2004</dd> 6079<dt> B3 </dt> <dd> 1002 x 1418</dd> 6080<dt> B4 </dt> <dd> 709 x 1002</dd> 6081<dt> B5 </dt> <dd> 501 x 709</dd> 6082<dt> C0 </dt> <dd> 2600 x 3677</dd> 6083<dt> C1 </dt> <dd> 1837 x 2600</dd> 6084<dt> C2 </dt> <dd> 1298 x 1837</dd> 6085<dt> C3 </dt> <dd> 918 x 1298</dd> 6086<dt> C4 </dt> <dd> 649 x 918</dd> 6087<dt> C5 </dt> <dd> 459 x 649</dd> 6088<dt> C6 </dt> <dd> 323 x 459</dd> 6089<dt> Flsa </dt> <dd> 612 x 936</dd> 6090<dt> Flse </dt> <dd> 612 x 936</dd> 6091<dt> HalfLetter </dt> <dd> 396 x 612</dd> 6092</dl> 6093 6094<p>This option is also used to place subimages when writing to a multi-image 6095format that supports offsets, such as GIF89 and MNG. When used for this 6096purpose the offsets are always measured from the top left corner of the canvas 6097and are not affected by the <a href="command-line-options.html#gravity">-gravity</a> option. To 6098position 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 6099file, a <a href="command-line-options.html#page">-page</a> option appearing ahead of the first image in 6100the sequence with nonzero width and height defines the width and height values 6101that are written in the <code>MHDR</code> chunk. Otherwise, the MNG width and 6102height are computed from the bounding box that contains all images in the 6103sequence. When writing a GIF89 file, only the bounding box method is used to 6104determine its dimensions.</p> 6105 6106<p>For a PostScript page, the image is sized as in <a 6107href="command-line-options.html#geometry">-geometry</a> but positioned relative to the <var>lower 6108left-hand corner</var> of the page by {+-}<code>x</code><var>offset</var>{+-}<code>y</code> <var>offset</var>. Use <a 6109href="command-line-options.html#page">-page 612x792</a>, for example, to center the image within the 6110page. If the image size exceeds the PostScript page, it is reduced to fit the 6111page. 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 6112corner of the page, unless the <a href="command-line-options.html#gravity">-gravity</a> option is 6113present with a value other than <var>NorthWest</var>.</p> 6114 6115<p>The default page dimensions for a TEXT image is 612x792.</p> 6116 6117<p>This option is used in concert with <a href="command-line-options.html#density">-density</a>.</p> 6118 6119<p>Use <a href="command-line-options.html#page">+page</a> to remove the page settings for an image.</p> 6120 6121<div style="margin: auto;"> 6122 <h3 class="magick-header"><a id="paint"></a>-paint <var>radius</var></h3> 6123</div> 6124 6125<p class="magick-description">simulate an oil painting.</p> 6126 6127<p>Each pixel is replaced by the most frequent color in a circular 6128neighborhood whose width is specified with <var>radius</var>.</p> 6129 6130<div style="margin: auto;"> 6131 <h3 class="magick-header"><a id="path"></a>-path <var>path</var></h3></div> 6132 6133<p class="magick-description">write images to this path on disk.</p> 6134 6135<div style="margin: auto;"> 6136 <h3 class="magick-header"><a id="pause_animate_"></a>-pause <var>seconds</var></h3> 6137</div> 6138 6139<p class="magick-description">Pause between animation loops</p> 6140 6141<p>Pause for the specified number of seconds before repeating the animation.</p> 6142 6143<div style="margin: auto;"> 6144 <h3 class="magick-header"><a id="pause_import_"></a>-pause <var>seconds</var></h3> 6145</div> 6146 6147<p class="magick-description">Pause between snapshots.</p> 6148 6149<p>Pause for the specified number of seconds before taking the next snapshot.</p> 6150 6151<div style="margin: auto;"> 6152 <h3 class="magick-header"><a id="perceptible"></a>-perceptible <var>epsilon</var></h3> 6153</div> 6154 6155<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> 6156 6157<div style="margin: auto;"> 6158 <h3 class="magick-header"><a id="ping"></a>-ping</h3> 6159</div> 6160 6161<p class="magick-description">efficiently determine image characteristics.</p> 6162 6163<div style="margin: auto;"> 6164 <h3 class="magick-header"><a id="pointsize"></a>-pointsize <var>value</var></h3> 6165</div> 6166 6167<p class="magick-description">pointsize of the PostScript, OPTION1, or TrueType font.</p> 6168 6169<div style="margin: auto;"> 6170 <h3 class="magick-header"><a id="polaroid"></a>-polaroid <var>angle</var></h3> 6171</div> 6172 6173<p class="magick-description">simulate a Polaroid picture.</p> 6174 6175<p>Use <code>+polaroid</code> to rotate the image at a random angle between -15 and +15 degrees.</p> 6176 6177<div style="margin: auto;"> 6178 <h3 class="magick-header"><a id="poly"></a>-poly <var>"wt,exp ..."</var></h3> 6179</div> 6180 6181<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> 6182 6183<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> 6184 6185<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> 6186 6187<p>The format is: <var>output = wt1*image1^exp1 + wt2*image2^exp2 </var>...</p> 6188 6189<p>Some simple uses are:</p> 6190<ul> 6191<li>A weighted sum of each image provided all weights add to unity and all exponents=1. If the 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> 6192<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> 6193</ul> 6194 6195<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> 6196 6197<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> 6198 6199 6200<div style="margin: auto;"> 6201 <h3 class="magick-header"><a id="posterize"></a>-posterize <var>levels</var></h3> 6202</div> 6203 6204<p class="magick-description">reduce the image to a limited number of color levels per channel.</p> 6205 6206<p>Very low values of <var>levels</var>, e.g., 2, 3, 4, have the most 6207visible effect.</p> 6208 6209<div style="margin: auto;"> 6210 <h3 class="magick-header"><a id="precision"></a>-precision <var>value</var></h3> 6211</div> 6212 6213<p class="magick-description">set the maximum number of significant digits to be printed.</p> 6214 6215<div style="margin: auto;"> 6216 <h3 class="magick-header"><a id="preview"></a>-preview <var>type</var></h3> 6217</div> 6218 6219<p class="magick-description">image preview type.</p> 6220 6221<p>Use this option to affect the preview operation of an image (e.g. 6222<code>convert file.png -preview Gamma Preview:gamma.png</code>). Choose from 6223these previews:</p> 6224 6225<pre class="pre-scrollable"> 6226AddNoise 6227Blur 6228Brightness 6229Charcoal 6230Despeckle 6231Dull 6232EdgeDetect 6233Gamma 6234Grayscale 6235Hue 6236Implode 6237JPEG 6238OilPaint 6239Quantize 6240Raise 6241ReduceNoise 6242Roll 6243Rotate 6244Saturation 6245Segment 6246Shade 6247Sharpen 6248Shear 6249Solarize 6250Spiff 6251Spread 6252Swirl 6253Threshold 6254Wave 6255</pre> 6256 6257<p>To print a complete list of previews, use the <a href="command-line-options.html#list">-list preview</a> option.</p> 6258 6259<p>The default preview is <code>JPEG</code>.</p> 6260 6261<div style="margin: auto;"> 6262 <h3 class="magick-header"><a id="print"></a>-print <var>string</var></h3> 6263</div> 6264 6265<p class="magick-description">interpret string and print to console.</p> 6266 6267<div style="margin: auto;"> 6268 <h3 class="magick-header"><a id="process"></a>-process <var>command</var></h3> 6269</div> 6270 6271<p class="magick-description">process the image with a custom image filter.</p> 6272 6273<p>The command arguments has the form <code>"module arg1 arg2 arg3 ... 6274argN"</code> where <code>module</code> is the name of the module to invoke (e.g. 6275"Analyze") and arg1 arg2 arg3 ... argN are an arbitrary number of arguments to 6276pass to the process module.</p> 6277 6278<div style="margin: auto;"> 6279 <h3 class="magick-header"><a id="profile"></a>-profile <var>filename</var><br/> 6280 +profile <var>profile_name</var></h3> 6281</div> 6282 6283<p class="magick-description">Manage ICM, IPTC, or generic profiles in an image.</p> 6284 6285<p>Using <a href="command-line-options.html#profile">-profile</a> <var>filename</var> adds an 6286ICM (ICC color management), IPTC (newswire information), or a generic profile 6287to the image.</p> 6288 6289<p>Use <a href="command-line-options.html#profile">+profile <var>profile_name</var></a> to 6290remove the indicated profile. ImageMagick uses standard filename globbing, so 6291wildcard expressions may be used to remove more than one profile. Here we 6292remove all profiles from the image except for the XMP profile: <code>+profile 6293"!xmp,*"</code>. </p> 6294 6295<p>Use <code>identify -verbose</code> to find out which profiles are in the 6296image file. Use <a href="command-line-options.html#strip">-strip</a> to remove all profiles (and 6297comments).</p> 6298 6299<p>To extract a profile, the <a href="command-line-options.html#profile">-profile</a> option is not 6300used. Instead, simply write the file to an image format such as <var>APP1, 8BIM, ICM,</var> or <var>IPTC</var>.</p> 6301 6302<p>For example, to extract the Exif data (which is stored in JPEG files in the 6303<var>APP1</var> profile), use.</p> 6304 6305<pre> 6306convert cockatoo.jpg profile.exif 6307</pre> 6308 6309<p>It is important to note that results may depend on whether or not the 6310original image already has an included profile. Also, keep in mind that <a 6311href="command-line-options.html#profile">-profile</a> is an "operator" (as opposed to a "setting") and 6312therefore a conversion is made each time it is encountered, in order, in the 6313command-line. For instance, in the following example, if the original image is 6314CMYK with profile, a CMYK-CMYK-RGB conversion results.</p> 6315 6316<pre> 6317convert CMYK.tif -profile "CMYK.icc" -profile "RGB.icc" RGB.tiff 6318</pre> 6319 6320<p>Furthermore, since ICC profiles are not necessarily symmetric, extra 6321conversion steps can yield unwanted results. CMYK profiles are often very 6322asymmetric since they involve 3−>4 and 4−>3 channel mapping. 6323</p> 6324 6325<div style="margin: auto;"> 6326 <h3 class="magick-header"><a id="quality"></a>-quality <var>value</var></h3> 6327</div> 6328 6329<p class="magick-description">JPEG/MIFF/PNG compression level.</p> 6330 6331<p>For the JPEG and MPEG image formats, quality is 1 (lowest image quality and 6332highest compression) to 100 (best quality but least effective compression). 6333The default is to use the estimated quality of your input image if it can 6334be determined, otherwise 92. When the quality is greater than 90, then the 6335chroma channels are not downsampled. 6336Use the <a href="command-line-options.html#sampling-factor">-sampling-factor</a> option to specify the 6337factors for chroma downsampling.</p> 6338 6339<p>For the JPEG-2000 image format, quality is mapped using a non-linear 6340equation to the compression ratio required by the Jasper library. This 6341non-linear equation is intended to loosely approximate the quality provided by 6342the JPEG v1 format. The default quality value 100, a request for non-lossy 6343compression. A quality of 75 results in a request for 16:1 compression.</p> 6344 6345<p>For the MNG and PNG image formats, the quality value sets the zlib 6346compression level (quality / 10) and filter-type (quality % 10). The default 6347PNG "quality" is 75, which means compression level 7 with adaptive PNG 6348filtering, unless the image has a color map, in which case it means 6349compression level 7 with no PNG filtering.</p> 6350 6351<p>For compression level 0 (quality value less than 10), the Huffman-only 6352strategy is used, which is fastest but not necessarily the worst 6353compression.</p> 6354 6355<p>If filter-type is 4 or less, the specified PNG filter-type is used for 6356all scanlines:</p> 6357 6358<dl class="dl-horizontal"> 6359<dt>0</dt><dd>none</dd> 6360<dt>1</dt><dd>sub</dd> 6361<dt>2</dt><dd>up</dd> 6362<dt>3</dt><dd>average</dd> 6363<dt>4</dt><dd>Paeth</dd> 6364</dl> 6365 6366<p>If filter-type is 5, adaptive filtering is used when quality is greater 6367than 50 and the image does not have a color map, otherwise no filtering is 6368used.</p> 6369 6370<p>If filter-type is 6, adaptive filtering 6371with <var>minimum-sum-of-absolute-values</var> is used.</p> 6372 6373<p>Only if the output is MNG, if filter-type is 7, the LOCO color 6374transformation (intrapixel differencing) and adaptive filtering 6375with <var>minimum-sum-of-absolute-values</var> are used.</p> 6376 6377<p>If the filter-type is 8 the zlib Z_RLE compression strategy (or the 6378Z_HUFFMAN_ONLY strategy, when compression level is 0) is used with 6379adaptive PNG filtering.</p> 6380 6381<p>If the filter-type is 9 the zlib Z_RLE compression strategy (or the 6382Z_HUFFMAN_ONLY strategy, when compression level is 0) is used with 6383no PNG filtering.</p> 6384 6385<p>The quality setting has no effect on the appearance or signature of PNG 6386and MNG images, since the compression is always lossless.</p> 6387 6388<p>Not all combinations of compression level, strategy, and PNG filter type 6389can be obtained using the -quality option. For more precise control, 6390you can use the PNG:compression-level=N, PNG:compression-strategy=N, and 6391PNG:compression-filter=N defines, respectively, instead. 6392See <a href="command-line-options.html#define">-define</a>. Values from the defines take precedence 6393over values from the -quality option.</p> 6394 6395<p>For further information, see 6396the <a href="http://www.w3.org/pub/WWW/TR">PNG</a> specification.</p> 6397 6398<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> 6399 6400<p>For the BPG image format, quality/2 is the actual BPG compression level (range from 0 to 51).</p> 6401 6402<div style="margin: auto;"> 6403 <h3 class="magick-header"><a id="quantize"></a>-quantize <var>colorspace</var></h3> 6404</div> 6405 6406<p class="magick-description">reduce colors using this colorspace.</p> 6407 6408<p>This setting defines the colorspace used to sort out and reduce the number 6409of colors needed by an image (for later dithering) by operators such as <a 6410href="command-line-options.html#colors" >-colors</a>, Note that color reduction also happens 6411automatically when saving images to color-limited image file formats, such as 6412GIF, and PNG8.</p> 6413 6414 6415<div style="margin: auto;"> 6416 <h3 class="magick-header"><a id="quiet"></a>-quiet</h3> 6417</div> 6418 6419<p class="magick-description">suppress all warning messages. Error messages are still reported.</p> 6420 6421<div style="margin: auto;"> 6422 <h3 class="magick-header"><a id="radial-blur"></a>-radial-blur <var>angle</var></h3> 6423</div> 6424 6425<p class="magick-description">Blur around the center of the image.</p> 6426 6427<p>Note that this is actually a rotational blur rather than a radial and as 6428such actually mis-named. </p> 6429 6430<p>The <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting will determine how 6431pixels which are outside the image proper are blurred into the final result. 6432</p> 6433 6434 6435<div style="margin: auto;"> 6436 <h3 class="magick-header"><a id="raise"></a>-raise <var>thickness</var></h3> 6437</div> 6438 6439<p class="magick-description">Lighten or darken image edges.</p> 6440 6441<p>This will create a 3-D effect. Use <a href="command-line-options.html#raise">-raise</a> to create 6442a raised effect, otherwise use <a href="command-line-options.html#raise">+raise</a>. </p> 6443 6444<p>Unlike the similar <a href="command-line-options.html#frame">-frame</a> option, <a 6445href="command-line-options.html#raise">-raise</a> does not alter the dimensions of the image.</p> 6446 6447<div style="margin: auto;"> 6448 <h3 class="magick-header"><a id="random-threshold"></a>-random-threshold <var>low</var>x<var>high</var></h3> 6449</div> 6450 6451<p class="magick-description">Apply a random threshold to the image.</p> 6452 6453<div style="margin: auto;"> 6454 <h3 class="magick-header"><a id="red-primary"></a>-red-primary <var>x,y</var></h3> 6455</div> 6456 6457<p class="magick-description">Set the red chromaticity primary point.</p> 6458 6459<div style="margin: auto;"> 6460 <h3 class="magick-header"><a id="regard-warnings"></a>-regard-warnings</h3> 6461</div> 6462 6463<p class="magick-description">Pay attention to warning messages.</p> 6464 6465<p>This option causes some warnings in some image formats to be treated 6466as errors. </p> 6467 6468<div style="margin: auto;"> 6469 <h3 class="magick-header"><a id="remap"></a>-remap <var>filename</var></h3> 6470</div> 6471 6472<p class="magick-description">Reduce the number of colors in an image to the colors used by this image.</p> 6473 6474<p>If the <a href="command-line-options.html#dither">-dither</a> setting is enabled (the default) then 6475the given colors are dithered over the image as necessary, otherwise the closest 6476color (in RGB colorspace) is selected to replace that pixel in the image. </p> 6477 6478<p>As a side effect of applying a <a href="command-line-options.html#remap">-remap</a> of colors across all 6479images in the current image sequence, all the images will have the same color 6480table. That means that when saved to a file format such as GIF, it will use 6481that color table as a single common or global color table, for all the images, 6482without requiring extra local color tables. </p> 6483 6484<p>Use <a href="command-line-options.html#remap">+remap</a> to reduce all images in the current image 6485sequence to use a common color map over all the images. This equivalent to 6486appending all the images together (without extra background colors) and color 6487reducing those images using <a href="command-line-options.html#colors">-colors</a> with a 256 color 6488limit, then <a href="command-line-options.html#remap">-remap</a> those colors over the original list of 6489images. This ensures all the images follow a single color map. </p> 6490 6491<p>If the number of colors over all the images is less than 256, then <a 6492href="command-line-options.html#remap">+remap</a> should not perform any color reduction or dithering, as 6493no color changes are needed. In that case, its only effect is to force the use 6494of a global color table. This recommended after using either <a 6495href="command-line-options.html#colors">-colors</a> or <a href="command-line-options.html#ordered-dither">-ordered-dither</a> to 6496reduce the number of colors in an animated image sequence. </p> 6497 6498<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> 6499 6500<div style="margin: auto;"> 6501 <h3 class="magick-header"><a id="region"></a>-region <var>geometry</var></h3> 6502</div> 6503 6504<p class="magick-description">Set a region in which subsequent operations apply.</p> 6505 6506<p>The <var>x</var> and <var>y</var> offsets are treated 6507in the same manner as in <a href="command-line-options.html#crop">-crop</a>.</p> 6508 6509<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 6510 6511<p>Use <code>+region</code> to remove any previously set regions.</p> 6512 6513<div style="margin: auto;"> 6514 <h3 class="magick-header"><a id="remote"></a>-remote</h3> 6515</div> 6516 6517<p class="magick-description">perform a remote operation.</p> 6518 6519<p>The only command recognized is the name of an image file to load.</p> 6520 6521<p>If you have more than one <a href="display.html">display</a> application 6522running simultaneously, use the <a href="command-line-options.html#window"> window</a> option to 6523specify which application to control.</p> 6524 6525<div style="margin: auto;"> 6526 <h3 class="magick-header"><a id="render"></a>-render</h3> 6527</div> 6528 6529<p class="magick-description">render vector operations.</p> 6530 6531<p>Use <a href="command-line-options.html#render">+render</a> to turn off rendering vector operations. 6532This useful when saving the result to vector formats such as MVG or SVG.</p> 6533 6534<div style="margin: auto;"> 6535<h3 class="magick-header"><a id="repage"></a>-repage <var>geometry</var></h3> 6536</div> 6537 6538<p class="magick-description">Adjust the canvas and offset information of the image.</p> 6539 6540<p>This option is like <a href="command-line-options.html#page">-page</a> but acts as an image operator 6541rather than a setting. You can separately set the canvas size or the offset 6542of the image on that canvas by only providing those components. </p> 6543 6544<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 6545 6546<p>If a <code>!</code> flag is given the offset given is added to the existing 6547offset to move the image relative to its previous position. This useful for 6548animation sequences. </p> 6549 6550<p>A given a canvas size of zero such as '<code>0x0</code>' forces it to 6551recalculate the canvas size so the image (at its current offset) will appear 6552completely on that canvas (unless it has a negative offset).</p> 6553 6554<p>Use <a href="command-line-options.html#repage">+repage</a> to completely remove/reset the virtual 6555canvas meta-data from the images. </p> 6556 6557<p>The <a href="command-line-options.html#set">-set</a> '<code>page</code>' option can be used to 6558directly assign virtual canvas meta-data. </p> 6559 6560 6561<div style="margin: auto;"> 6562 <h3 class="magick-header"><a id="resample"></a>-resample <var>horizontal</var>x<var>vertical</var></h3> 6563</div> 6564 6565<p class="magick-description">Resample image to specified horizontal and vertical resolution.</p> 6566 6567<p>Resize the image so that its rendered size remains the same as the original 6568at the specified target resolution. For example, if a 300 DPI image renders at 65693 inches by 2 inches on a 300 DPI device, when the image has been resampled to 657072 DPI, it will render at 3 inches by 2 inches on a 72 DPI device. Note that 6571only a small number of image formats (e.g. JPEG, PNG, and TIFF) are capable of 6572storing the image resolution. For formats which do not support an image 6573resolution, the original resolution of the image must be specified via <a 6574href="command-line-options.html#density">-density</a> on the command line prior to specifying the 6575resample resolution.</p> 6576 6577<p>Note that Photoshop stores and obtains image resolution from a proprietary 6578embedded profile. If this profile exists in the image, then Photoshop will 6579continue to treat the image using its former resolution, ignoring the image 6580resolution specified in the standard file header.</p> 6581 6582<div style="margin: auto;"> 6583 <h3 class="magick-header"><a id="resize"></a>-resize <var>geometry</var></h3> 6584</div> 6585 6586<p class="magick-description">Resize an image.</p> 6587 6588<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 6589ignored, and the <a href="command-line-options.html#gravity">-gravity</a> option has no effect.</p> 6590 6591<p>If the <a href="command-line-options.html#filter">-filter</a> option 6592or <code>-define filter:option=value</code> precedes the <a 6593href="command-line-options.html#resize">-resize</a> option, the image is resized with the specified 6594filter.</p> 6595 6596<p>Many image processing algorithms assume your image is in a linear-light 6597coding. If your image is gamma-corrected, you can remove the nonlinear gamma 6598correction, apply the transform, then restore it like this:</p> 6599 6600<pre> 6601convert portrait.jpg -gamma .45455 -resize 25% -gamma 2.2 \ 6602 -quality 92 passport.jpg 6603</pre> 6604 6605<div style="margin: auto;"> 6606 <h3 class="magick-header"><a id="respect-parentheses"></a>-respect-parentheses</h3> 6607</div> 6608 6609<p class="magick-description">settings remain in effect until parenthesis boundary.</p> 6610 6611<div style="margin: auto;"> 6612 <h3 class="magick-header"><a id="reverse"></a>-reverse</h3> 6613</div> 6614 6615<p class="magick-description">Reverse the order of images in the current image list.</p> 6616 6617 6618<div style="margin: auto;"> 6619 <h3 class="magick-header"><a id="roll"></a>-roll {<var>+-</var>}<var>x</var>{<var>+-</var>}<var>y</var></h3> 6620</div> 6621 6622<p class="magick-description">roll an image vertically or horizontally by the amount given.</p> 6623 6624<p>A negative <var>x</var> offset rolls the image right-to-left. 6625A negative <var>y</var> offset rolls the image bottom-to-top.</p> 6626 6627 6628<div style="margin: auto;"> 6629 <h3 class="magick-header"><a id="rotate"></a>-rotate <var>degrees</var>{<var><</var>}{<var>></var>}</h3> 6630</div> 6631 6632<p class="magick-description">Apply Paeth image rotation (using shear operations) to the image.</p> 6633 6634<p>Use <code>></code> to rotate the image only if its width exceeds the 6635height. <code><</code> rotates the image <var>only</var> if its width is less 6636than the height. For example, if you specify <code>-rotate "-90>"</code> and 6637the image size is 480x640, the image is not rotated. However, if the image is 6638640x480, it is rotated by -90 degrees. If you use <code>></code> or 6639<code><</code>, enclose it in quotation marks to prevent it from being 6640misinterpreted as a file redirection.</p> 6641 6642<p>Empty triangles in the corners, left over from rotating the image, are 6643filled with the <code>background</code> color. </p> 6644 6645<p>See also the <a href="command-line-options.html#distort">-distort</a> operator and specifically the 6646'<code>ScaleRotateTranslate</code>' distort method. </p> 6647 6648 6649<div style="margin: auto;"> 6650 <h3 class="magick-header"><a id="sample"></a>-sample <var>geometry</var></h3> 6651</div> 6652 6653<p class="magick-description">minify / magnify the image with pixel subsampling and pixel replication, respectively.</p> 6654 6655<p>Change the image size simply by directly sampling the pixels original 6656from the image. When magnifying, pixels are replicated in blocks. When 6657minifying, pixels are sub-sampled (i.e., some rows and columns are skipped 6658over). </p> 6659 6660<p>The results are thus equivalent to using <a href="command-line-options.html#resize">-resize</a> with 6661a <a href="command-line-options.html#filter">-filter</a> setting of <code>point</code> (nearest 6662neighbor), though <a href="command-line-options.html#sample">-sample</a> is a lot faster, as it 6663avoids all the filter processing of the image. As such it completely ignores 6664the current <a href="command-line-options.html#filter">-filter</a> setting. </p> 6665 6666<p>The key feature of the <a href="command-line-options.html#sample">-sample</a> is that no new colors 6667will be added to the resulting image, though some colors may disappear. </p> 6668 6669<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 6670ignored, unlike <a href="command-line-options.html#resize">-resize</a>. </p> 6671 6672 6673<p>The actual sampling point is the middle of the sub-region being sampled. 6674As such a single pixel sampling of an image will take the middle pixel, (or 6675top-left-middle if image has even dimensions). However the <a 6676href="command-line-options.html#define">-define</a> '<code>sample:offset</code>' can be set to modify 6677this position some other location within each sub-region being sampled, as 6678a percentage offset.</p> 6679 6680<p>By default this value is '<code>50</code>' for the midpoint, but could be set 6681to '<code>0</code>' for top-left, '<code>100</code>' for bottom-right, or with 6682separate X and Y offsets such as '<code>0x50</code>' for left-middle edge of 6683sampling sub-region.</p> 6684 6685 6686<div style="margin: auto;"> 6687 <h3 class="magick-header"><a id="sampling-factor"></a>-sampling-factor <var>horizontal-factor</var>x<var>vertical-factor</var></h3> 6688</div> 6689 6690<p class="magick-description">sampling factors used by JPEG or MPEG-2 encoder and YUV decoder/encoder.</p> 6691 6692<p>This option specifies the sampling factors to be used by the JPEG encoder 6693for chroma downsampling. If this option is omitted, the JPEG library will use 6694its own default values. When reading or writing the YUV format and when 6695writing the M2V (MPEG-2) format, use <a 6696href="command-line-options.html#sampling-factor">-sampling-factor 2x1</a> or <a 6697href="command-line-options.html#sampling-factor">-sampling-factor 4:2:2</a> to specify the 4:2:2 6698downsampling method.</p> 6699 6700<div style="margin: auto;"> 6701 <h3 class="magick-header"><a id="scale"></a>-scale <var>geometry</var></h3> 6702</div> 6703 6704<p class="magick-description">minify / magnify the image with pixel block averaging and pixel replication, respectively.</p> 6705 6706<p>Change the image size simply by replacing pixels by averaging pixels 6707together when minifying, or replacing pixels when magnifying. </p> 6708 6709<p>The results are thus equivalent to using <a href="command-line-options.html#resize">-resize</a> with 6710a <a href="command-line-options.html#filter">-filter</a> setting of <code>box</code>. Though it is a lot 6711faster, as it avoids all the filter processing of the image. As such it 6712completely ignores the current <a href="command-line-options.html#filter">-filter</a> setting. </p> 6713 6714<p>If when shrinking (minifying) images the original image is some integer 6715multiple of the new image size, the number of pixels averaged together to 6716produce the new pixel color is the same across the whole image. This is 6717a special case known as 'binning' and is often used as a method of reducing 6718noise in image such as those generated by digital cameras, especially in low 6719light conditions. </p> 6720 6721 6722<div style="margin: auto;"> 6723 <h3 class="magick-header"><a id="scene"></a>-scene <var>value</var></h3> 6724</div> 6725 6726<p class="magick-description">set scene number.</p> 6727 6728<p>This option sets the scene number of an image or the first image in an image sequence.</p> 6729 6730<div style="margin: auto;"> 6731 <h3 class="magick-header"><a id="screen"></a>-screen</h3> 6732</div> 6733 6734<p class="magick-description">specify the screen to capture.</p> 6735 6736<p>This option indicates that the GetImage request used to obtain the image 6737should be done on the root window, rather than directly on the specified 6738window. In this way, you can obtain pieces of other windows that overlap the 6739specified window, and more importantly, you can capture menus or other popups 6740that are independent windows but appear over the specified window.</p> 6741 6742<div style="margin: auto;"> 6743 <h3 class="magick-header"><a id="seed"></a>-seed</h3> 6744</div> 6745 6746<p class="magick-description">seed a new sequence of pseudo-random numbers</p> 6747 6748<div style="margin: auto;"> 6749 <h3 class="magick-header"><a id="segment"></a>-segment <var>cluster-threshold</var>x<var>smoothing-threshold</var></h3> 6750</div> 6751 6752<p class="magick-description">segment the colors of an image.</p> 6753 6754<p>Segment an image by analyzing the histograms of the color components and 6755identifying units that are homogeneous with the fuzzy c-means technique. This 6756is part of the ImageMagick color quantization routines. </p> 6757 6758<p>Specify <var>cluster threshold</var> as the number of pixels in 6759each cluster that must exceed the cluster threshold to be considered valid. 6760<var>Smoothing threshold</var> eliminates noise in the second 6761derivative of the histogram. As the value is increased, you can expect 6762a smoother second derivative. The default is 1.5.</p> 6763 6764<p>If the <a href="command-line-options.html#verbose">-verbose</a> setting is defined, a detailed report 6765of the color clusters is returned.</p> 6766 6767 6768<div style="margin: auto;"> 6769 <h3 class="magick-header"><a id="selective-blur"></a>-selective-blur <var>radius</var><br />-selective-blur <var>radius</var>x<var>sigma</var>{<var>+threshold</var>}</h3> 6770</div> 6771 6772<p class="magick-description">Selectively blur pixels within a contrast threshold.</p> 6773 6774<p>Blurs those pixels that are less than or equal to the threshold in 6775contrast. The threshold may be expressed as a fraction of <var>QuantumRange</var> or as a percentage.</p> 6776 6777<div style="margin: auto;"> 6778 <h3 class="magick-header"><a id="separate"></a>-separate</h3> 6779</div> 6780 6781<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> 6782 6783<div style="margin: auto;"> 6784 <h3 class="magick-header"><a id="sepia-tone"></a>-sepia-tone <var>percent-threshold</var></h3> 6785</div> 6786 6787<p class="magick-description">simulate a sepia-toned photo.</p> 6788 6789<p>Specify <var>threshold</var> as the percent threshold of the intensity (0 - 99.9%).</p> 6790 6791<p>This option applies a special effect to the image, similar to the effect 6792achieved 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 6793toning. A threshold of 80% is a good starting point for a reasonable 6794tone.</p> 6795 6796 6797 6798<div style="margin: auto;"> 6799 <h3 class="magick-header"><a id="set"></a>-set <var>key value</var></h3> 6800 <h3 class="magick-header">+set <var>key</var></h3> 6801</div> 6802 6803<p class="magick-description">sets image attributes and properties for images in the current image sequence.</p> 6804 6805<p>This will assign (or modify) specific settings attached to all the images 6806in the current image sequence. Using the <a href="command-line-options.html#set">+set</a> form of the 6807option will either remove, or reset that setting to a default state, as 6808appropriate. </p> 6809 6810<p>For example, it will modify specific well known image meta-data 6811'attributes' such as those normally overridden by: the options <a 6812href="command-line-options.html#delay" >-delay</a>, <a href="command-line-options.html#dispose" >-dispose</a>, and <a 6813href="command-line-options.html#page" >-page</a>, <a href="command-line-options.html#colorspace" >-colorspace</a>; generally 6814assigned before the image is read in, by using a <var>key</var> of 6815the same name. </p> 6816 6817<p>If the given <var>key</var> does not match a specific known 6818'attribute ', such as shown above, the setting is stored as a a free form 6819'property' string. Such settings are listed in <a href="command-line-options.html#verbose" 6820>-verbose</a> information ("<code>info:</code>" output format) as "Properties". 6821</p> 6822 6823<p>This includes string 'properties' that are set by and assigned to images 6824using the options <a href="command-line-options.html#comment" >-comment</a>, <a href="command-line-options.html#label" 6825>-label</a>, <a href="command-line-options.html#caption" >-caption</a>. These options actually assign 6826a global 'artifact' which are automatically assigned (and any <a href="escape.html" >Format Percent 6827Escapes</a> expanded) to images as they are read in. For example:</p> 6828 6829<pre> 6830-> convert rose: -set comment 'Rose is a rose is a rose is a rose' rose.png 6831identify -format %c rose.png 6832Rose is a rose is a rose is a rose 6833</pre> 6834 6835<p>The set value can also make use of <a href="escape.html" >Format and Print Image 6836Properties</a> in the defined value. For example:</p> 6837 6838<pre> 6839-> convert rose: -set origsize '%wx%h' -resize 50% \ 6840 -format 'Old size = %[origsize] New size = %wx%h' info: 6841Old size = 70x46 New size = 35x23 6842</pre> 6843 6844<p>Other well known 'properties' that are available include: 6845'<code>date:create</code>' and '<code>date:modify</code>' and 6846'<code>signature</code>'. </p> 6847 6848<p>The <a href="command-line-options.html#repage">-repage</a> operator will also allow you to modify 6849the '<code>page</code>' attribute of an image for images already in memory (also 6850see <a href="command-line-options.html#repage">-page</a>). However it is designed to provide a finer 6851control of the sub-parts of this 'attribute'. The <a href="command-line-options.html#set">-set page</a> 6852option will only provide a direct, unmodified assignment of '<code>page</code>' 6853attribute. </p> 6854 6855<p>This option can also associate a colorspace or profile with your image. 6856For example,</p> 6857 6858<pre> 6859convert image.psd -set profile ISOcoated_v2_eci.icc image-icc.psd 6860</pre> 6861 6862<p>Some 'properties' must be defined in a specific way to be used. For 6863example only 'properties' prefixed with "<code>filename:</code>" can be used to 6864modify the output filename of an image. For example</p> 6865 6866<pre> 6867convert rose: -set filename:mysize '%wx%h' 'rose_%[filename:mysize].png' 6868</pre> 6869 6870<p>If the setting value is prefixed with "<code>option:</code>" the setting will 6871be saved as a global "Artifact" exactly as if it was set using the <a 6872href="command-line-options.html#define" >-define</a> option. As such settings are global in scope, they 6873can be used to pass 'attributes' and 'properties' of one specific image, 6874in a way that allows you to use them in a completely different image, even if 6875the original image has long since been modified or destroyed. For example: </p> 6876 6877<pre> 6878convert rose: -set option:rosesize '%wx%h' -delete 0 \ 6879 label:'%[rosesize]' label_size_of_rose.gif" 6880</pre> 6881 6882<p>Note that <a href="escape.html" >Format Percent Escapes</a> will only match 6883a 'artifact' if the given <var>key</var> does not match an existing 6884'attribute' or 'property'. </p> 6885 6886<p>You can set the attributes of the image registry by prefixing the value 6887with <code>registry:</code>.</p> 6888 6889<p>The <a href="command-line-options.html#set">-set profile</a> option can also be used to inject 6890previously-formatted ancillary chunks into the output PNG file, using 6891the commandline option as shown below or by setting the profile via a 6892programming interface:</p> 6893 6894<pre> 6895convert in.png -set profile PNG-chunk-x:<filename> out.png 6896</pre> 6897 6898<p>where <var>x</var> is a location flag and 6899<var>filename</var> is a file containing the chunk 6900name in the first 4 bytes, then a colon (":"), followed by the chunk data. 6901This encoder will compute the chunk length and CRC, so those must not 6902be included in the file.</p> 6903 6904<p>"x" can be "b" (before PLTE), "m" (middle, i.e., between PLTE and IDAT), 6905or "e" (end, i.e., after IDAT). If you want to write multiple chunks 6906of the same type, then add a short unique string after the "x" to prevent 6907subsequent profiles from overwriting the preceding ones, e.g.,</p> 6908 6909 6910<pre> 6911convert in.png -set profile PNG-chunk-b01:file01 \ 6912 -profile PNG-chunk-b02:file02 out.png 6913</pre> 6914 6915<div style="margin: auto;"> 6916 <h3 class="magick-header"><a id="shade"></a>-shade <var>azimuth</var>x<var>elevation</var></h3> 6917</div> 6918 6919<p class="magick-description">shade the image using a distant light source.</p> 6920 6921<p>Specify <var>azimuth</var> and <var>elevation</var> as 6922the position of the light source. Use <a href="command-line-options.html#shade">+shade</a> to return 6923the shading results as a grayscale image.</p> 6924 6925<div style="margin: auto;"> 6926 <h3 class="magick-header"><a 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> 6927</div> 6928 6929<p class="magick-description">simulate an image shadow.</p> 6930 6931<div style="margin: auto;"> 6932 <h3 class="magick-header"><a 6933id="shared-memory"></a>-shared-memory</h3> 6934</div> 6935 6936<p class="magick-description">use shared memory.</p> 6937 6938<p>This option specifies whether the utility should attempt to use shared 6939memory for pixmaps. ImageMagick must be compiled with shared memory support, 6940and the display must support the <var>MIT-SHM</var> extension. 6941Otherwise, this option is ignored. The default is <code>True</code>.</p> 6942 6943<div style="margin: auto;"> 6944 <h3 class="magick-header"><a id="sharpen"></a>-sharpen <var>radius</var><br />-sharpen <var>radius</var>x<var>sigma</var></h3> 6945</div> 6946 6947<p class="magick-description">sharpen the image.</p> 6948 6949<p>Use a Gaussian operator of the given radius and standard deviation (sigma).</p> 6950 6951<div style="margin: auto;"> 6952 <h3 class="magick-header"><a id="shave"></a>-shave <var>geometry</var></h3> 6953</div> 6954 6955<p class="magick-description">Shave pixels from the image edges.</p> 6956 6957<p>The <var>size</var> portion of the <var>geometry</var> 6958argument specifies the width of the region to be removed from both sides of 6959the image and the height of the regions to be removed from top and bottom. 6960Offsets are ignored.</p> 6961 6962<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 6963 6964<div style="margin: auto;"> 6965 <h3 class="magick-header"><a id="shear"></a>-shear <var>Xdegrees</var>[x<var>Ydegrees</var>]</h3> 6966</div> 6967 6968<p class="magick-description">Shear the image along the x-axis and/or y-axis.</p> 6969 6970<p>The shear angles may be positive, negative, or zero. When <var>Ydegrees</var> is omitted it defaults to 0. When both angles are 6971given, the horizontal component of the shear is performed before the vertical 6972component.</p> 6973 6974<p>Shearing slides one edge of an image along the x-axis or y-axis (i.e., 6975horizontally or vertically, respectively),creating a parallelogram. The amount 6976of each is controlled by the respective shear angle. For horizontal shears, 6977<var>Xdegrees</var> is measured clockwise relative to "up" (the 6978negative y-axis), sliding the top edge to the right when 0°<<var>Xdegrees</var><90° and to the left when 90°<<var>Xdegrees</var><180°. For vertical shears <var>Ydegrees</var> is measured clockwise relative to "right" (the 6979positive x-axis), sliding the right edge down when 0°<<var>Ydegrees</var><90° and up when 90°<<var>Ydegrees</var><180°.</p> 6980 6981<p>Empty triangles left over from shearing the image are filled with the color 6982defined by the <a href="command-line-options.html#fill">-background</a> option. The color is specified 6983using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p> 6984 6985<p>The horizontal shear is performed before the vertical part. This is 6986important to note, since horizontal and vertical shears do not 6987<var>commute</var>, i.e., the order matters in a sequence of shears. For 6988example, the following two commands are not equivalent.</p> 6989 6990<pre> 6991convert logo: -shear 20x0 -shear 0x60 logo-sheared.png 6992convert logo: -shear 0x60 -shear 20x0 logo-sheared.png 6993</pre> 6994 6995<p>The first of the two commands above is equivalent to the following, except 6996for the amount of empty space created; the command that follows generates 6997a smaller image, and so is a better choice in terms of time and space.</p> 6998 6999<pre> 7000convert logo: -shear 20x60 logo-sheared.png 7001</pre> 7002 7003<div style="margin: auto;"> 7004 <h3 class="magick-header"><a id="sigmoidal-contrast"></a>-sigmoidal-contrast <var>contrast</var>x<var>mid-point</var></h3> 7005</div> 7006 7007<p class="magick-description">increase the contrast without saturating highlights or shadows.</p> 7008 7009<p>Increase the contrast of the image using a sigmoidal transfer function 7010without saturating highlights or shadows. <var>Contrast</var> 7011indicates how much to increase the contrast. For example, 0 is none, 3 is 7012typical and 20 is a lot. 7013</p> 7014 7015<p>The <var>mid-point</var> indicates where the maximum change 7016'slope' in contrast should fall in the resultant image (0 is white; 50% is 7017middle-gray; 100% is black). </p> 7018 7019<p>By default the image contrast is increased, use <var>+sigmoidal-contrast</var> to decrease the contrast.</p> 7020 7021<p>To achieve the equivalent of a sigmoidal brightness change (similar to 7022a gamma adjustment), you would use <var>-sigmoidal-contrast 7023{brightness}x0%</var> to increase brightness and <var>+sigmoidal-contrast {brightness}x0%</var> to decrease brightness. 7024Note the use of '0' fo rthe mid-point of the sigmoidal curve. </p> 7025 7026<p>Using a very high <var>contrast</var> will produce a sort of 7027'smoothed thresholding' of the image. Not as sharp (with high aliasing 7028effects) of a true threshold, but with tapered gray-levels around the threshold 7029<var>mid-point</var>. </p> 7030 7031<div style="margin: auto;"> 7032 <h3 class="magick-header"><a id="silent"></a>-silent</h3> 7033 7034 7035</div> 7036 7037<p class="magick-description">operate silently. This option is only used 7038by the <a href="import.html">import</a> tool.</p> 7039 7040<div style="margin: auto;"> 7041 <h3 class="magick-header"><a id="similarity-threshold"></a>-similarity-threshold <var>value</var></h3> 7042</div> 7043 7044<p class="magick-description">minimum RMSE for subimage match.</p> 7045 7046<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> 7047 7048<div style="margin: auto;"> 7049 <h3 class="magick-header"><a id="size"></a>-size <var>width</var>[x<var>height</var>][<var>+offset</var>]</h3> 7050</div> 7051 7052<p class="magick-description">set the width and height of the image.</p> 7053 7054<p>Use this option to specify the width and height of raw images whose 7055dimensions are unknown such as <code>GRAY</code>, <code>RGB</code>, or 7056<code>CMYK</code>. In addition to width and height, use <a 7057href="command-line-options.html#size">-size</a> with an offset to skip any header information in the 7058image or tell the number of colors in a <code>MAP</code> image file, (e.g. -size 7059640x512+256).</p> 7060 7061<p>For Photo CD images, choose from these sizes:</p> 7062 7063<pre> 7064192x128 7065384x256 7066768x512 70671536x1024 70683072x2048 7069</pre> 7070 7071<div style="margin: auto;"> 7072 <h3 class="magick-header"><a id="sketch"></a>-sketch <var>radius</var><br />-sketch <var>radius</var>x<var>sigma</var>+<var>angle</var></h3> 7073</div> 7074 7075<p class="magick-description">simulate a pencil sketch.</p> 7076 7077<p>Sketch with the given radius, standard deviation (sigma), and angle. The 7078angle given is the angle toward which the image is sketched. That is the 7079direction people would consider the object is coming from. </p> 7080 7081<div style="margin: auto;"> 7082 <h3 class="magick-header"><a id="smush"></a>-smush <var>offset</var></h3> 7083</div> 7084 7085<p class="magick-description">smush an image sequence together.</p> 7086 7087<div style="margin: auto;"> 7088 <h3 class="magick-header"><a id="snaps"></a>-snaps <var>value</var></h3> 7089</div> 7090 7091<p class="magick-description">Set the number of screen snapshots.</p> 7092 7093<p>Use this option to grab more than one image from the X server screen, to create an animation sequence.</p> 7094 7095<div style="margin: auto;"> 7096 <h3 class="magick-header"><a id="solarize"></a>-solarize <var>percent-threshold</var></h3> 7097</div> 7098 7099<p class="magick-description">negate all pixels above the threshold level.</p> 7100 7101<p>Specify <var>factor</var> as the percent threshold of the intensity (0 - 99.9%).</p> 7102 7103<p>This option produces a <var>solarization</var> effect seen when 7104exposing a photographic film to light during the development process.</p> 7105 7106<div style="margin: auto;"> 7107 <h3 class="magick-header"><a id="sparse-color"></a>-sparse-color <var>method</var> '<var>x</var>,<var>y</var> <var>color</var> ...'</h3> 7108</div> 7109 7110<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> 7111 7112 7113<dl class="dl-horizontal"> 7114 <dt>barycentric</dt> 7115 <dd>three point triangle of color given 3 points. 7116 Giving only 2 points will form a linear gradient between those points. 7117 The gradient generated extends beyond the triangle created by those 7118 3 points. </dd> 7119 <dt>bilinear</dt> 7120 <dd>Like barycentric but for 4 points. Less than 4 points 7121 fall back to barycentric. </dd> 7122 <dt>voronoi</dt> 7123 <dd>Simply map each pixel to the to nearest color point 7124 given. The result are polygonal 'cells' of solid color. </dd> 7125 <dt>manhatten</dt> 7126 <dd>Like voronoi, but resulting polygonal 'cells' are mapped to a fixed coordinate system.</dd> 7127 <dt>shepards</dt> 7128 <dd>Colors points biased on the ratio of inverse distance 7129 squared. Generating spots of color in a sea of the average of 7130 colors. </dd> 7131 <dt>inverse</dt> 7132 <dd>Colors points biased on the ratio of inverse distance. 7133 This generates sharper points of color rather than rounded spots of 7134 '<code>shepards</code>' Generating spots of color in a sea of the 7135 average of colors. </dd> 7136</dl> 7137 7138<p>The points are placed according to the images location on the virtual 7139canvas (<a href="command-line-options.html#page" >-page</a> or <a href="command-line-options.html#repage" >-repage</a> 7140offset), and do not actually have to exist on the given image, but may be 7141some point beyond the edge of the image. All points are floating point values. 7142</p> 7143 7144<p>Only the color channels defined by the <a href="command-line-options.html#channel" >-channel</a> are 7145modified, which means that by default matte/alpha transparency channel is not 7146effected. Typically transparency channel is turned off either before or after 7147the operation. </p> 7148 7149<p>Of course if some color points are transparent to generate a transparent 7150gradient, then the image also requires transparency enabled to store the 7151values. </p> 7152 7153<p>All the above methods when given a single point of color will replace all 7154the colors in the image with the color given, regardless of the point. This is 7155logical, and provides an alternative technique to recolor an image to some 7156default value. </p> 7157 7158 7159<div style="margin: auto;"> 7160 <h3 class="magick-header"><a id="splice"></a>-splice <var>geometry</var></h3> 7161</div> 7162 7163<p class="magick-description">Splice the current background color into the image.</p> 7164 7165<p>This will add rows and columns of the current <a 7166href="command-line-options.html#background">-background</a> color into the given image according to the 7167given <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 7168image into four quadrants, separating them by the inserted rows and columns. 7169</p> 7170 7171<p>If a dimension of geometry is zero no rows or columns will be added for that 7172dimension. Similarly using a zero offset with the appropriate <a 7173href="command-line-options.html#gravity">-gravity</a> setting will add rows and columns to the edges of 7174the image, padding the image only along that one edge. Edge padding is what <a 7175href="command-line-options.html#splice">-splice</a> is most commonly used for. </p> 7176 7177<p>If the exact same <var>geometry</var> and <a 7178href="command-line-options.html#gravity">-gravity</a> is later used with <a href="command-line-options.html#chop">-chop</a> the 7179added added all splices removed. </p> 7180 7181<div style="margin: auto;"> 7182 <h3 class="magick-header"><a id="spread"></a>-spread <var>amount</var></h3> 7183</div> 7184 7185<p class="magick-description">displace image pixels by a random amount.</p> 7186 7187<p>The argument <var>amount</var> defines the size of the 7188neighborhood around each pixel from which to choose a candidate pixel to 7189blend.</p> 7190 7191<p>The lookup is controlled by the <a href="command-line-options.html#interpolate">-interpolate</a> setting.</p> 7192 7193<div style="margin: auto;"> 7194 <h3 class="magick-header"><a id="statistic"></a>-statistic <var>type</var> <var>geometry</var></h3> 7195</div> 7196 7197<p class="magick-description">replace each pixel with corresponding statistic from the neighborhood.</p> 7198 7199<p>Choose from these statistic types:</p> 7200<dl class="dl-horizontal"> 7201<dt>Gradient</dt><dd>maximum difference (max - min) value in neighborhood</dd> 7202<dt>Maximum</dt><dd>maximum value per channel in neighborhood</dd> 7203<dt>Minimum</dt><dd>minimum value per channel in neighborhood</dd> 7204<dt>Mean</dt><dd>average value per channel in neighborhood</dd> 7205<dt>Median</dt><dd>median value per channel in neighborhood</dd> 7206<dt>Mode</dt><dd>mode (most frequent) value per channel in neighborhood</dd> 7207<dt>Nonpeak</dt><dd>value just before or after the median value per channel in neighborhood</dd> 7208<dt>RMS</dt><dd>root mean square value per channel in neighborhood</dd> 7209<dt>StandardDeviation</dt><dd> standard deviation value per channel in neighborhood</dd> 7210</dl> 7211 7212<div style="margin: auto;"> 7213 <h3 class="magick-header"><a id="stegano"></a>-stegano <var>offset</var></h3> 7214</div> 7215 7216<p class="magick-description">hide watermark within an image.</p> 7217 7218<p>Use an offset to start the image hiding some number of pixels from the 7219beginning of the image. Note this offset and the image size. You will need 7220this information to recover the steganographic image (e.g. display -size 7221320x256+35 stegano:image.png).</p> 7222 7223<div style="margin: auto;"> 7224 <h3 class="magick-header"><a id="stereo"></a>-stereo <var>+x</var>{<var>+y</var>}</h3> 7225</div> 7226 7227<p class="magick-description">composite two images to create a red / cyan stereo anaglyph.</p> 7228 7229<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> 7230 7231<div style="margin: auto;"> 7232 <h3 class="magick-header"><a id="storage-type"></a>-storage-type <var>type</var></h3> 7233</div> 7234 7235<p class="magick-description">pixel storage type. Here are the valid types:</p> 7236 7237<dl class="dl-horizontal"> 7238<dt>char</dt><dd>unsigned characters</dd> 7239<dt>double</dt><dd>doubles</dd> 7240<dt>float</dt><dd>floats</dd> 7241<dt>integer</dt><dd>integers</dd> 7242<dt>long</dt><dd>longs</dd> 7243<dt>quantum</dt><dd>pixels in the native depth of your ImageMagick distribution</dd> 7244<dt>short</dt><dd>unsigned shorts</dd> 7245</dl> 7246 7247<p>Float and double types are normalized from 0.0 to 1.0 otherwise the pixels 7248values range from 0 to the maximum value the storage type can support.</p> 7249 7250<div style="margin: auto;"> 7251 <h3 class="magick-header"><a id="stretch"></a>-stretch <var>fontStretch</var></h3> 7252</div> 7253 7254<p class="magick-description">Set a type of stretch style for fonts.</p> 7255 7256<p>This setting suggests a type of stretch that ImageMagick should try to 7257apply to the currently selected font family. Select <var>fontStretch</var> from the following.</p> 7258 7259<pre> 7260Any 7261Condensed 7262Expanded 7263ExtraCondensed 7264ExtraExpanded 7265Normal 7266SemiCondensed 7267SemiExpanded 7268UltraCondensed 7269UltraExpanded 7270</pre> 7271 7272<p>To print a complete list of stretch types, use <a href="command-line-options.html#list">-list 7273stretch</a>.</p> 7274 7275<p>For other settings that affect fonts, see the options <a 7276href="command-line-options.html#font">-font</a>, <a href="command-line-options.html#family">-family</a>, <a 7277href="command-line-options.html#style">-style</a>, and <a href="command-line-options.html#weight">-weight</a>. </p> 7278 7279<div style="margin: auto;"> 7280 <h3 class="magick-header"><a id="strip"></a>-strip</h3> 7281</div> 7282 7283<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> 7284 7285<div style="margin: auto;"> 7286 <h3 class="magick-header"><a id="stroke"></a>-stroke <var>color</var></h3> 7287</div> 7288 7289<p class="magick-description">color to use when stroking a graphic primitive.</p> 7290 7291<p>The color is specified using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p> 7292 7293<p>See <a href="command-line-options.html#draw">-draw</a> for further details.</p> 7294 7295<div style="margin: auto;"> 7296 <h3 class="magick-header"><a id="strokewidth"></a>-strokewidth <var>value</var></h3> 7297</div> 7298 7299<p class="magick-description">set the stroke width.</p> 7300 7301<p>See <a href="command-line-options.html#draw">-draw</a> for further details.</p> 7302 7303<div style="margin: auto;"> 7304 <h3 class="magick-header"><a id="style"></a>-style <var>fontStyle</var></h3> 7305</div> 7306 7307<p class="magick-description">Set a font style for text.</p> 7308 7309<p>This setting suggests a font style that ImageMagick should try to apply to 7310the currently selected font family. Select <var>fontStyle</var> from 7311the following.</p> 7312 7313<pre> 7314Any 7315Italic 7316Normal 7317Oblique 7318</pre> 7319 7320<p>For other settings that affect fonts, see the options <a 7321href="command-line-options.html#font">-font</a>, <a href="command-line-options.html#family">-family</a>, <a 7322href="command-line-options.html#stretch">-stretch</a>, and <a href="command-line-options.html#weight">-weight</a>. </p> 7323 7324<div style="margin: auto;"> 7325 <h3 class="magick-header"><a id="subimage-search"></a>-subimage-search</h3> 7326</div> 7327 7328<p class="magick-description">search for subimage.</p> 7329 7330<p>This option is required to have compare search for the best match location 7331of a small image within a larger image. This search will produce two images 7332(or two frames). The first is the "difference" image and the second will 7333be the "match score" image.</p> 7334 7335<p>The "match-score" image is smaller containing a pixel for ever possible 7336position of the top-left corner of the given sub-image. that is its size will 7337be the size of the larger_image - sub_image + 1. The brightest location in 7338this image is the location s the locate on the best match that is also 7339reported. Note that this may or may not be a perfect match, and the actual 7340brightness will reflect this. Other bright 'peaks' can be used to locate other 7341possible matching locations. </p> 7342 7343<p>Note that the search will try to compare the sub-image at every possible 7344location in the larger image, as such it can be very slow. The smaller the 7345sub-image the faster this search is. </p> 7346 7347 7348<div style="margin: auto;"> 7349 <h3 class="magick-header"><a id="swap"></a>-swap <var>index,index</var></h3> 7350</div> 7351 7352<p class="magick-description">Swap the positions of two images in the image sequence.</p> 7353 7354<p>For example, <a href="command-line-options.html#swap">-swap 0,2</a> swaps the first and the third 7355images in the current image sequence. Use <a href="command-line-options.html#swap">+swap</a> to switch 7356the last two images in the sequence.</p> 7357 7358<div style="margin: auto;"> 7359 <h3 class="magick-header"><a id="swirl"></a>-swirl <var>degrees</var></h3> 7360</div> 7361 7362<p class="magick-description">swirl image pixels about the center.</p> 7363 7364<p><var>Degrees</var> defines the tightness of the swirl.</p> 7365 7366<div style="margin: auto;"> 7367 <h3 class="magick-header"><a id="synchronize"></a>-synchronize</h3> 7368</div> 7369 7370<p class="magick-description">synchronize image to storage device.</p> 7371 7372<p>Set to "true" to ensure all image data is fully flushed and synchronized 7373to disk. There is a performance penalty, but the benefits include ensuring a 7374valid image file in the event of a system crash and early reporting if there 7375is not enough disk space for the image pixel cache.</p> 7376 7377<div style="margin: auto;"> 7378 <h3 class="magick-header"><a id="taint"></a>-taint</h3> 7379</div> 7380 7381<p class="magick-description">Mark the image as modified.</p> 7382 7383<div style="margin: auto;"> 7384 <h3 class="magick-header"><a id="text-font"></a>-text-font <var>name</var></h3> 7385</div> 7386 7387<p class="magick-description">font for writing fixed-width text.</p> 7388 7389<p>Specifies the name of the preferred font to use in fixed (typewriter style) 7390formatted text. The default is 14 point <var>Courier</var>.</p> 7391 7392<p>You can tag a font to specify whether it is a PostScript, TrueType, or 7393OPTION1 font. For example, <code>Courier.ttf</code> is a TrueType font and 7394<code>x:fixed</code> is OPTION1.</p> 7395 7396<div style="margin: auto;"> 7397 <h3 class="magick-header"><a id="texture"></a>-texture <var>filename</var></h3> 7398</div> 7399 7400<p class="magick-description">name of texture to tile onto the image background.</p> 7401 7402<div style="margin: auto;"> 7403 <h3 class="magick-header"><a id="threshold"></a>-threshold <var>value</var>{<var>%</var>}</h3> 7404</div> 7405 7406<!-- {<var>green,blue,opacity</var>} 7407<p>If the green or blue value is omitted, these channels use the same value as 7408the first one provided. If all three color values are the same, the result is 7409a bi-level image. If the opacity threshold is omitted, OpaqueOpacity is used 7410and any partially transparent pixel becomes fully transparent.</p> 7411--> 7412 7413<p class="magick-description">Apply simultaneous black/white threshold to the image.</p> 7414 7415<p>Any pixel values (more specifically, those channels set using <a href="command-line-options.html#channel">‑channel</a>) that exceed the specified threshold are reassigned the 7416maximum channel value, while all other values are assigned the minimum.</p> 7417 7418<p> The threshold value can be given as a percentage or as an absolute integer 7419value corresponding to the desired channel value. When given as an integer, 7420the minimum attainable value is 0 (corresponding to black when all channels 7421are affected), but the maximum value (corresponding to white) is that of the 7422<code>quantum depth</code> of the particular build of ImageMagick, and is 7423therefore dependent on the installation. For that reason, a reasonable 7424recommendation for most applications is to specify the threshold values as 7425a percentage. </p> 7426 7427<p> The following would force pixels with red values above 50% to have 100% 7428red values, while those at or below 50% red would be set to 0 in the red 7429channel. The green, blue, and alpha channels (if present) would be unchanged. 7430</p> 7431 7432<pre> 7433convert in.png -channel red -threshold 50% out.png 7434</pre> 7435 7436<p>As (possibly) impractical but instructive examples, the following would 7437generate an all-black and an all-white image with the same dimensions as the 7438input image.</p> 7439 7440 7441<pre> 7442convert in.png -threshold 100% black.png 7443convert in.png -threshold -1 white.png 7444</pre> 7445 7446<p>Note that the values of the transparency channel is treated as 'matte' 7447values (0 is opaque) and not as 'alpha' values (0 is transparent).</p> 7448 7449<p> See also <a href="command-line-options.html#black-threshold">‑black‑threshold</a> and <a href="command-line-options.html#white-threshold">‑white‑threshold</a>. 7450</p> 7451 7452<div style="margin: auto;"> 7453 <h3 class="magick-header"><a id="thumbnail"></a>-thumbnail <var>geometry</var></h3> 7454</div> 7455 7456<p class="magick-description">Create a thumbnail of the image.</p> 7457 7458<p>This is similar to <a href="command-line-options.html#resize">-resize</a>, except it is optimized 7459for speed and any image profile, other than a color profile, is removed to 7460reduce the thumbnail size. To strip the color profiles as well, add <a 7461href="command-line-options.html#strip">-strip</a> just before of after this option.</p> 7462 7463<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 7464 7465<div style="margin: auto;"> 7466 <h3 class="magick-header"><a id="tile"></a>-tile <var>filename</var></h3> 7467</div> 7468 7469<p class="magick-description">Set the tile image used for filling a subsequent graphic primitive.</p> 7470 7471<div style="margin: auto;"> 7472 <h3 class="magick-header">-tile <var>geometry</var></h3> 7473</div> 7474 7475<p class="magick-description">Specify the layout of images.</p> 7476 7477<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 7478 7479<div style="margin: auto;"> 7480 <h3 class="magick-header">-tile</h3> 7481</div> 7482 7483<p class="magick-description">Specifies that a subsequent composite operation is repeated across and down image.</p> 7484 7485<div style="margin: auto;"> 7486 <h3 class="magick-header"><a id="tile-offset"></a>-tile-offset {<var>+-</var>}<var>x</var>{<var>+-</var>}<var>y</var></h3> 7487</div> 7488 7489<p class="magick-description">Specify the offset for tile images, relative to the background image it is tiled on.</p> 7490 7491<p>This should be set before the tiling image is set by <a href="command-line-options.html#tile" 7492>-tile</a> or <a href="command-line-options.html#texture" >-texture</a>, or directly applied for 7493creating a tiled canvas using <code>TILE:</code> or <code>PATTERN:</code> input 7494formats. </p> 7495 7496<p>Internally ImageMagick does a <a href="command-line-options.html#roll" >-roll</a> of the tile image 7497by the arguments given when the tile image is set. </p> 7498 7499<div style="margin: auto;"> 7500 <h3 class="magick-header"><a id="tint"></a>-tint <var>value</var></h3> 7501</div> 7502 7503<p class="magick-description">Tint the image with the fill color.</p> 7504 7505<p>Tint the image with the fill color.</p> 7506 7507<p>Specify the amount of tinting as a percentage. Pure colors like black, 7508white red, yellow, will not be affected by -tint. Only mid-range colors such 7509as the various shades of grey.</p> 7510 7511<div style="margin: auto;"> 7512 <h3 class="magick-header"><a id="title"></a>-title <var>string</var></h3> 7513</div> 7514 7515<p class="magick-description">Assign a title to displayed image.", "animate", "display", "montage</p> 7516 7517<p>Use this option to assign a specific title to the image. This assigned to 7518the image window and is typically displayed in the window title bar. 7519Optionally you can include the image filename, type, width, height, Exif data, 7520or other image attribute by embedding special format characters described 7521under the <a href="command-line-options.html#format">-format</a> option.</p> 7522 7523<p>For example,</p> 7524 7525<pre> 7526-title "%m:%f %wx%h" 7527</pre> 7528 7529<p>produces an image title of <code>MIFF:bird.miff 512x480</code> for an image 7530titled <code>bird.miff</code> and whose width is 512 and height is 480.</p> 7531 7532 7533<div style="margin: auto;"> 7534 <h3 class="magick-header"><a id="transform"></a>-transform</h3> 7535</div> 7536 7537<p class="magick-description">transform the image.</p> 7538 7539<p>This option applies the transformation matrix from a previous <a href="command-line-options.html#affine">-affine</a> option.</p> 7540 7541<pre> 7542convert -affine 2,2,-2,2,0,0 -transform bird.ppm bird.jpg 7543</pre> 7544 7545 7546<p>This operator has been now been superseded by the <a 7547href="command-line-options.html#distort">-distort</a> '<code>AffineProjection</code>' method. </p> 7548 7549 7550<div style="margin: auto;"> 7551 <h3 class="magick-header"><a id="transparent"></a>-transparent <var>color</var></h3> 7552</div> 7553 7554<p class="magick-description">Make this color transparent within the image.</p> 7555 7556<p>The <var>color</var> argument is defined using the format 7557described under the <a href="command-line-options.html#fill">-fill</a> option. The <a href="command-line-options.html#fuzz" 7558>-fuzz</a> setting can be used to match and replace colors similar to the one 7559given. </p> 7560 7561<p>Use <a href="command-line-options.html#transparent" >+transparent</a> to invert the pixels matched. 7562that is make all non-matching colors transparent. </p> 7563 7564<p>The <a href="command-line-options.html#opaque">-opaque</a> operator is exactly the same as <a 7565href="command-line-options.html#transparent" >-transparent</a> but replaces the matching color with the 7566current <a href="command-line-options.html#fill">-fill</a> color setting, rather than transparent. 7567However the <a href="command-line-options.html#transparent" >-transparent</a> operator also ensures 7568that the image has an alpha channel enabled, as per "<code><a href="command-line-options.html#alpha" 7569>-alpha</a> set</code>", and does not require you to modify the <a 7570href="command-line-options.html#channel">-channel</a> to enable alpha channel handling. </p> 7571 7572<p>Note that this does not define the color as being the 'transparency color' 7573used for color-mapped image formats, such as GIF. For that use <a 7574href="command-line-options.html#transparent-color" >-transparent-color</a> </p> 7575 7576 7577<div style="margin: auto;"> 7578 <h3 class="magick-header"><a id="transparent-color"></a>-transparent-color <var>color</var></h3> 7579</div> 7580 7581<p class="magick-description">Set the transparent color.</p> 7582 7583<p>Sometimes this is used for saving to image formats such as 7584GIF and PNG8 which uses this color to represent boolean transparency. This 7585does not make a color transparent, it only defines what color the transparent 7586color is in the color palette of the saved image. Use <a 7587href="command-line-options.html#transparent">-transparent</a> to make an opaque color transparent.</p> 7588 7589<p>This option allows you to have both an opaque visible color, as well as a 7590transparent color of the same color value without conflict. That is, you can 7591use the same color for both the transparent and opaque color areas within an 7592image. This, in turn, frees to you to select a transparent color that is 7593appropriate when an image is displayed by an application that does not handle a 7594transparent color index, while allowing ImageMagick to correctly handle images of this 7595type. </p> 7596 7597<p>The default transparent color is <code>#00000000</code>, which is fully transparent black.</p> 7598 7599<div style="margin: auto;"> 7600 <h3 class="magick-header"><a id="transpose"></a>-transpose</h3> 7601</div> 7602 7603<p class="magick-description">Mirror the image along the top-left to bottom-right diagonal.</p> 7604 7605<p> This option mathematically transposes the pixel array. It is equivalent to the sequence <code>-flip -rotate 90</code>. 7606</p> 7607 7608<div style="margin: auto;"> 7609 <h3 class="magick-header"><a id="transverse"></a>-transverse</h3> 7610</div> 7611 7612<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> 7613 7614 7615<div style="margin: auto;"> 7616 <h3 class="magick-header"><a id="treedepth"></a>-treedepth <var>value</var></h3> 7617</div> 7618 7619<p class="magick-description">tree depth for the color reduction algorithm.</p> 7620 7621<p>Normally, this integer value is zero or one. A value of zero or one causes 7622the use of an optimal tree depth for the color reduction algorithm.</p> 7623 7624<p>An optimal depth generally allows the best representation of the source 7625image with the fastest computational speed and the least amount of memory. 7626However, the default depth is inappropriate for some images. To assure the 7627best representation, try values between 2 and 8 for this parameter. Refer to 7628the <a href="quantize.html" 7629>color reduction algorithm</a> for more details.</p> 7630 7631<p>The <a href="command-line-options.html#colors">-colors</a> or <a href="command-line-options.html#monochrome">-monochrome</a> 7632option, or writing to an image format which requires color reduction, is 7633required for this option to take effect.</p> 7634 7635<div style="margin: auto;"> 7636 <h3 class="magick-header"><a id="trim"></a>-trim</h3> 7637</div> 7638 7639<p class="magick-description">trim an image.</p> 7640 7641<p>This option removes any edges that are exactly the same color as the corner 7642pixels. Use <a href="command-line-options.html#fuzz">-fuzz</a> to make <a href="command-line-options.html#trim">-trim</a> remove 7643edges that are nearly the same color as the corner pixels.</p> 7644 7645<p>The page or virtual canvas information of the image is preserved allowing 7646you to extract the result of the <a href="command-line-options.html#trim">-trim</a> operation from the 7647image. Use a <a href="command-line-options.html#repage">+repage</a> to remove the virtual canvas page 7648information if it is unwanted.</p> 7649 7650<p>If the trimmed image 'disappears' an warning is produced, and a special 7651single pixel transparent 'missed' image is returned, in the same way as when a 7652<a href="command-line-options.html#crop">-crop</a> operation 'misses' the image proper. </p> 7653 7654 7655<div style="margin: auto;"> 7656 <h3 class="magick-header"><a id="type"></a>-type <var>type</var></h3> 7657</div> 7658 7659<p class="magick-description">the image type.</p> <p>Choose from: <code>Bilevel</code>, 7660<code>Grayscale</code>, <code>GrayscaleMatte</code>, <code>Palette</code>, 7661<code>PaletteMatte</code>, <code>TrueColor</code>, <code>TrueColorMatte</code>, 7662<code>ColorSeparation</code>, or <code>ColorSeparationMatte</code>.</p> 7663 7664<p>Normally, when a format supports different subformats such as grayscale and 7665truecolor, the encoder will try to choose an efficient subformat. The <a 7666href="command-line-options.html#type">-type</a> option can be used to override this behavior. For 7667example, to prevent a JPEG from being written in grayscale format even though 7668only gray pixels are present, use.</p> 7669 7670<pre> 7671convert bird.png -type TrueColor bird.jpg 7672</pre> 7673 7674<p>Similarly, use <a href="command-line-options.html#type">-type TrueColorMatte</a> to force the 7675encoder to write an alpha channel even though the image is opaque, if the 7676output format supports transparency.</p> 7677 7678<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> 7679 7680<div style="margin: auto;"> 7681 <h3 class="magick-header"><a id="undercolor"></a>-undercolor <var>color</var></h3> 7682</div> 7683 7684<p class="magick-description">set the color of the annotation bounding box.</p> 7685 7686<p>The color is specified using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p> 7687 7688<p>See <a href="command-line-options.html#draw">-draw</a> for further details.</p> 7689 7690 7691<div style="margin: auto;"> 7692 <h3 class="magick-header"><a id="update"></a>-update <var>seconds</var></h3> 7693</div> 7694 7695<p class="magick-description">detect when image file is modified and redisplay.</p> 7696 7697<p>Suppose that while you are displaying an image the file that is currently 7698displayed is over-written. <code>display</code> will automagically detect that 7699the input file has been changed and update the displayed image 7700accordingly.</p> 7701 7702 7703<div style="margin: auto;"> 7704 <h3 class="magick-header"><a id="unique-colors"></a>-unique-colors</h3> 7705</div> 7706 7707<p class="magick-description">discard all but one of any pixel color.</p> 7708 7709 7710<div style="margin: auto;"> 7711 <h3 class="magick-header"><a id="units"></a>-units <var>type</var></h3> 7712</div> 7713 7714<p class="magick-description">the units of image resolution.</p> 7715 7716<p>Choose from: <code>Undefined</code>, <code>PixelsPerInch</code>, or 7717<code>PixelsPerCentimeter</code>. This option is normally used in conjunction 7718with the <a href="command-line-options.html#density">-density</a> option.</p> 7719 7720 7721<div style="margin: auto;"> 7722 <h3 class="magick-header"><a id="unsharp"></a>-unsharp <var>radius</var><br />-unsharp <var>radius</var>x<var>sigma</var>{<var>+gain</var>}{<var>+threshold</var>}</h3> 7723</div> 7724 7725<p class="magick-description">sharpen the image with an unsharp mask operator.</p> 7726 7727<p>The <a href="command-line-options.html#unsharp">-unsharp</a> option sharpens an image. The image is 7728convolved with a Gaussian operator of the given radius and standard deviation 7729(sigma). For reasonable results, radius should be larger than sigma. Use 7730a radius of 0 to have the method select a suitable radius.</p> 7731 7732<p>The parameters are:</p> 7733 7734<dl class="dl-horizontal"> 7735<dt>radius</dt> 7736<dd>The radius of the Gaussian, in pixels, not counting the center pixel (default 0).</dd> 7737<dt>sigma</dt> 7738<dd>The standard deviation of the Gaussian, in pixels (default 1.0).</dd> 7739<dt>gain</dt> 7740<dd>The fraction of the difference between the original and the blur image that is added back into the original (default 1.0).</dd> 7741<dt>threshold</dt> 7742<dd>The threshold, as a fraction of <var>QuantumRange</var>, needed to apply the difference amount (default 0.05).</dd> 7743</dl> 7744 7745<div style="margin: auto;"> 7746 <h3 class="magick-header"><a id="verbose"></a>-verbose</h3> 7747</div> 7748 7749<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> 7750 7751 7752<div style="margin: auto;"> 7753 <h3 class="magick-header"><a id="version"></a>-version</h3> 7754</div> 7755 7756<p class="magick-description">print ImageMagick version string and exit.</p> 7757 7758 7759<div style="margin: auto;"> 7760 <h3 class="magick-header"><a id="view"></a>-view <var>string</var></h3> 7761</div> 7762 7763<p class="magick-description">FlashPix viewing parameters.</p> 7764 7765 7766<div style="margin: auto;"> 7767 <h3 class="magick-header"><a id="vignette"></a>-vignette <var>radius</var>{x<var>sigma</var>}{<var>+-</var>}<var>x</var>{<var>+-</var>}<var>y</var>{<var>%</var>}</h3> 7768</div> 7769 7770<p class="magick-description">soften the edges of the image in vignette style.</p> 7771 7772<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> 7773 7774<div style="margin: auto;"> 7775 <h3 class="magick-header"><a id="virtual-pixel"></a>-virtual-pixel <var>method</var></h3> 7776</div> 7777 7778<p class="magick-description">Specify contents of <var>virtual pixels</var>.</p> 7779 7780<p>This option defines what color source should be used if and when a color 7781lookup completely 'misses' the source image. The color(s) that appear to 7782surround the source image. Generally this color is derived from the source 7783image, but could also be set to a specify background color. </p> 7784 7785<p>Choose from these methods:</p> 7786 7787<dl class="dl-horizontal"> 7788<dt>background</dt><dd>the area surrounding the image is the background color</dd> 7789<dt>black</dt><dd>the area surrounding the image is black</dd> 7790<dt>checker-tile</dt><dd>alternate squares with image and background color</dd> 7791<dt>dither</dt><dd>non-random 32x32 dithered pattern</dd> 7792<dt>edge</dt><dd>extend the edge pixel toward infinity</dd> 7793<dt>gray</dt><dd>the area surrounding the image is gray</dd> 7794<dt>horizontal-tile</dt><dd>horizontally tile the image, background color above/below</dd> 7795<dt>horizontal-tile-edge</dt><dd>horizontally tile the image and replicate the side edge pixels</dd> 7796<dt>mirror</dt><dd>mirror tile the image</dd> 7797<dt>random</dt><dd>choose a random pixel from the image</dd> 7798<dt>tile</dt><dd>tile the image (default)</dd> 7799<dt>transparent</dt><dd>the area surrounding the image is transparent blackness</dd> 7800<dt>vertical-tile</dt><dd>vertically tile the image, sides are background color</dd> 7801<dt>vertical-tile-edge</dt><dd>vertically tile the image and replicate the side edge pixels</dd> 7802<dt>white</dt><dd>the area surrounding the image is white</dd> 7803</dl> 7804 7805<p>The default value is "edge".</p> 7806 7807<p>This most important for distortion operators such as <a href="command-line-options.html#distort" 7808>-distort</a>, <a href="command-line-options.html#implode" >-implode</a>, and <a href="command-line-options.html#fx" >-fx</a>. 7809However it also effects operations that may access pixels just outside the 7810image proper, such as <a href="command-line-options.html#convolve">-convolve</a>, <a 7811href="command-line-options.html#blur">-blur</a>, and <a href="command-line-options.html#sharpen">-sharpen</a>. </p> 7812 7813<p>To print a complete list of virtual pixel types, use the <a 7814href="command-line-options.html#list">-list virtual-pixel</a> option.</p> 7815 7816 7817<div style="margin: auto;"> 7818 <h3 class="magick-header"><a id="visual"></a>-visual <var>type</var></h3> 7819</div> 7820 7821<p class="magick-description">Animate images using this X visual type.", 'animate', 'display'</p> 7822 7823<p>Choose from these visual classes:</p> 7824 7825<pre> 7826StaticGray TrueColor 7827GrayScale DirectColor 7828StaticColor default 7829PseudoColor visual id 7830</pre> 7831 7832<p>The X server must support the visual you choose, otherwise an error occurs. 7833If a visual is not specified, the visual class that can display the most 7834simultaneous colors on the default screen is chosen.</p> 7835 7836 7837<div style="margin: auto;"> 7838 <h3 class="magick-header"><a id="watermark"></a>-watermark <var>brightness</var>x<var>saturation</var></h3> 7839</div> 7840 7841<p class="magick-description">Watermark an image using the given percentages of brightness and saturation.</p> 7842 7843<p>Take a grayscale image (with alpha mask) and modify the destination image's 7844brightness according to watermark image's grayscale value and the 7845<var>brightness</var> percentage. The destinations color saturation 7846attribute is just direct modified by the <var>saturation</var> 7847percentage, which defaults to 100 percent (no color change). </p> 7848 7849 7850<div style="margin: auto;"> 7851 <h3 class="magick-header"><a id="wave"></a>-wave <var>amplitude</var><br />-wave <var>amplitude</var>x<var>wavelength</var></h3> 7852</div> 7853 7854<p class="magick-description">Shear the columns of an image into a sine wave.</p> 7855 7856<div style="margin: auto;"> 7857 <h3 class="magick-header"><a id="wavelet-denoise"></a>-wavelet-denoise <var>threshold</var><br />-wavelet-denoise <var>threshold</var>x<var>softness</var></h3> 7858</div> 7859 7860<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> 7861 7862<div style="margin: auto;"> 7863 <h3 class="magick-header"><a id="weight"></a>-weight <var>fontWeight</var></h3> 7864</div> 7865 7866<p class="magick-description">Set a font weight for text.</p> 7867 7868<p>This setting suggests a font weight that ImageMagick should try to apply to 7869the currently selected font family. Use a positive integer for 7870<var>fontWeight</var> or select from the following.</p> 7871 7872<dl class="dl-horizontal"> 7873<dt>Thin </dt> 7874<dd>Same as <var>fontWeight</var> = 100.</dd> 7875<dt>ExtraLight </dt> 7876<dd>Same as <var>fontWeight</var> = 200.</dd> 7877<dt>Light </dt> 7878<dd>Same as <var>fontWeight</var> = 300.</dd> 7879<dt>Normal </dt> 7880<dd>Same as <var>fontWeight</var> = 400.</dd> 7881<dt>Medium </dt> 7882<dd>Same as <var>fontWeight</var> = 500.</dd> 7883<dt>DemiBold </dt> 7884<dd>Same as <var>fontWeight</var> = 600.</dd> 7885<dt>Bold </dt> 7886<dd>Same as <var>fontWeight</var> = 700.</dd> 7887<dt>ExtraBold </dt> 7888<dd>Same as <var>fontWeight</var> = 800.</dd> 7889<dt>Heavy </dt> 7890<dd>Same as <var>fontWeight</var> = 900.</dd> 7891</dl> 7892<br/> 7893 7894<p>To print a complete list of weight types, use <a href="command-line-options.html#list">-list weight</a>.</p> 7895 7896<p>For other settings that affect fonts, see the options <a 7897href="command-line-options.html#font">-font</a>, <a href="command-line-options.html#family">-family</a>, <a 7898href="command-line-options.html#stretch">-stretch</a>, and <a href="command-line-options.html#style">-style</a>. </p> 7899 7900<div style="margin: auto;"> 7901 <h3 class="magick-header"><a id="white-point"></a>-white-point <var>x,y</var></h3> 7902</div> 7903 7904<p class="magick-description">chromaticity white point.</p> 7905 7906<div style="margin: auto;"> 7907 <h3 class="magick-header"><a id="white-threshold"></a>-white-threshold <var>value</var>{<var>%</var>}</h3> 7908</div> 7909 7910<p class="magick-description">Force to white all pixels above the threshold while leaving all pixels at or below the threshold unchanged.</p> 7911 7912<p> The threshold value can be given as a percentage or as an absolute integer 7913value within [0, <var>QuantumRange</var>] corresponding to the 7914desired <a href="command-line-options.html#channel">‑channel</a> value. See <a href="command-line-options.html#threshold">‑threshold</a>for more details on thresholds and resulting values. </p> 7915 7916<div style="margin: auto;"> 7917 <h3 class="magick-header"><a id="window"></a>-window <var>id</var></h3> 7918</div> 7919 7920<p class="magick-description">Make the image the background of a window.", 'animate', 'display'</p> 7921 7922<p><var>id</var> can be a window id or name. Specify <code>root</code> 7923to select X's root window as the target window.</p> 7924 7925<p>By default the image is tiled onto the background of the target window. If 7926<code>backdrop</code> or <a href="command-line-options.html#geometry">-resize</a> are specified, the 7927image is surrounded by the background color. Refer to <code>X RESOURCES</code> 7928for details.</p> 7929 7930<p>The image will not display on the root window if the image has more unique 7931colors than the target window colormap allows. Use <a 7932href="command-line-options.html#colors">-colors</a> to reduce the number of colors.</p> 7933 7934<div style="margin: auto;"> 7935 <h3 class="magick-header"><a id="window-group"></a>-window-group</h3> 7936</div> 7937 7938<p class="magick-description">specify the window group.</p> 7939 7940<div style="margin: auto;"> 7941 <h3 class="magick-header"><a id="write"></a>-write <var>filename</var></h3> 7942</div> 7943 7944<p class="magick-description">write an image sequence.</p> 7945 7946<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> 7947 7948<p>Use <a href="command-line-options.html#compress">-compress</a> to specify the type of image compression.</p> 7949</div> 7950</div> 7951 7952 7953 7954 <footer class="magick-footer"> 7955 <p><a href="support.html">Donate</a> • 7956 <a href="sitemap.html">Sitemap</a> • 7957 <a href="links.html">Related</a> • 7958 <a href="architecture.html">Architecture</a> 7959</p> 7960 <p><a href="command-line-options.html#">Back to top</a> • 7961 <a href="http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x89AB63D48277377A">Public Key</a> • 7962 <a href="http://www.imagemagick.org/script/contact.php">Contact Us</a></p> 7963 <p><small>© 1999-2016 ImageMagick Studio LLC</small></p> 7964 </footer> 7965</div><!-- /.container --> 7966 7967 <script src="https://localhost/ajax/libs/jquery/1.11.3/jquery.min.js"></script> 7968 <script src="../js/magick.html"></script> 7969</div> 7970</body> 7971</html> 7972<!-- Magick Cache 17th June 2016 14:42 -->
