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The backslash is the Unix <var>line-continuation</var> character. In the Windows shell, use a carat character (<code>^</code>) for line-continuation. We use the Unix style on these web pages, as above. Sometimes, however, the lines are wrapped by your browser if the browser window is small enough, but the command-lines, shown in white, are still intended to be typed as one line. Line continuation characters need not be entered. The <var>parentheses</var> that are <var>escaped</var> above using the backslash are not escaped in Windows. There are some other differences between Windows and Unix (involving quotation marks, for instance), but we'll discuss some of those issues later, as they arise. </p> 109 110<p>Without knowing much about the ImageMagick command-line, you can probably surmise that the first command above converts an image in the JPEG format to one in the PNG format. However, very few may realize the second, more complex command, gives a flat two-dimensional label a three-dimensional look with rich textures and simulated depth:</p> 111 112<ul> 113 <a href="../images/label.gif"><img src="../images/label.gif" width="78" height="53" alt="label" /></a> 114<img style="margin-top:16px; margin-bottom:17px;" src="../images/right.gif" width="20" height="20" alt="==>" /> 115 <a href="../images/button.gif"> 116 <img src="../images/button.gif" width="78" height="53" alt="button" /></a> 117</ul> 118 119 120<p>Here we show percent completion of a task as a shaded cylinder:</p> 121 122<ul> 123 <img src="../images/cylinder_shaded.png" width="320" height="200" alt="Shaded Cylinder" /> 124</ul> 125 126<p>Given the complexity of the rendering, you might be surprised it is accomplished by a single command-line:</p> 127 128<pre class="highlight"><code>magick -size 320x90 canvas:none -stroke snow4 -size 1x90 -tile gradient:white-snow4 \ 129 -draw 'roundrectangle 16, 5, 304, 85 20,40' +tile -fill snow \ 130 -draw 'roundrectangle 264, 5, 304, 85 20,40' -tile gradient:chartreuse-green \ 131 -draw 'roundrectangle 16, 5, 180, 85 20,40' -tile gradient:chartreuse1-chartreuse3 \ 132 -draw 'roundrectangle 140, 5, 180, 85 20,40' +tile -fill none \ 133 -draw 'roundrectangle 264, 5, 304, 85 20,40' -strokewidth 2 \ 134 -draw 'roundrectangle 16, 5, 304, 85 20,40' \( +clone -background snow4 \ 135 -shadow 80x3+3+3 \) +swap -background none -layers merge \( +size -pointsize 90 \ 136 -strokewidth 1 -fill red label:'50 %' -trim +repage \( +clone -background firebrick3 \ 137 -shadow 80x3+3+3 \) +swap -background none -layers merge \) -insert 0 -gravity center \ 138 -append -background white -gravity center -extent 320x200 cylinder_shaded.png</code></pre> 139 140<p>In the next sections we dissect the anatomy of the ImageMagick command-line. Hopefully, after carefully reading and better understanding how the command-line works, you should be able to accomplish complex image-processing tasks without resorting to the sometimes daunting <a href="develop.html">program interfaces</a>.</p> 141 142<p>See <a href="https://legacy.imagemagick.org/Usage/">Examples of ImageMagick Usage</a> for additional help when using ImageMagick from the command-line.</p> 143 144<h2><a class="anchor" id="anatomy"></a>The Anatomy of the Command-line</h2> 145<p>The ImageMagick command-line consists of</p> 146 147<ol> 148<li>one or more required input filenames.</li> 149<li>zero, one, or more image settings.</li> 150<li>zero, one, or more image operators.</li> 151<li>zero, one, or more image sequence operators.</li> 152<li>zero, one, or more image stacks.</li> 153<li>zero or one output image filenames (required by 154<a href="magick.html">magick</a>, 155<a href="../www/convert.html">convert</a>, 156<a href="../www/composite.html">composite</a>, 157<a href="montage.html">montage</a>, 158<a href="../www/compare.html">compare</a>, 159<a href="import.html">import</a>, 160<a href="conjure.html">conjure</a>). 161</li> 162</ol> 163 164<p>You can find a detailed explanation of each of the constituent parts of the command-line in the sections that follow.</p> 165 166<h2><a class="anchor" id="input"></a>Input Filename</h2> 167 168<p>ImageMagick extends the concept of an input filename to include:</p> 169<ul> 170<li>filename globbing</li> 171<li>an explicit image format</li> 172<li>using built-in images and patterns</li> 173<li>STDIN, STDOUT, and file descriptors</li> 174<li>selecting certain frames from an image</li> 175<li>selecting a region of an image</li> 176<li>forcing an inline image resize</li> 177<li>forcing an inline image crop</li> 178<li>using filename references</li> 179</ul> 180 181<p>These extensions are explained in the next few paragraphs.</p> 182 183<h5>Filename Globbing</h5> 184<p>In Unix shells, certain characters such as the asterisk (<code>*</code>) and question mark (<code>?</code>) automagically cause lists of filenames to be generated based on pattern matches. This feature is known as globbing. ImageMagick supports filename globbing for systems, such as Windows, that does not natively support it. For example, suppose you want to convert <code>1.jpg</code>, <code>2.jpg</code>, <code>3.jpg</code>, <code>4.jpg</code>, and <code>5.jpg</code> in your current directory to a GIF animation. You can conveniently refer to all of the JPEG files with this command: 185</p> 186 187<pre class="highlight"><code>magick *.jpg images.gif</code></pre> 188 189<h5>Explicit Image Format</h5> 190<p>Images are stored in a myriad of image formats including 191the better known JPEG, PNG, TIFF and others. ImageMagick must know the format 192of the image before it can be read and processed. Most formats have a 193signature within the image that uniquely identifies the format. Failing 194that, ImageMagick leverages the filename extension to determine the format. 195For example, <code>image.jpg</code> or <code>image.JPG</code> tells ImageMagick 196it is reading an image in the JPEG format. </p> 197 198 <p>In some cases the image may not contain a signature 199and/or the filename does not identify the image format. In these cases an 200explicit image format must be specified. For example, suppose our image 201is named <code>image</code> and contains raw red, green, and blue intensity 202values. ImageMagick has no way to automagically determine the image format 203so we explicitly set one: 204</p> 205 206<pre class="highlight"><code>magick -size 640x480 -depth 8 rgb:image image.png</code></pre> 207 208<h5>Built-in Images and Patterns</h5> 209 210<p>ImageMagick has a number of built-in <a href="formats.html#builtin-images">images</a> and <a href="formats.html#builtin-patterns">patterns</a>. To utilize the checkerboard pattern, for example, use: 211</p> 212 213<pre class="highlight"><code>magick -size 640x480 pattern:checkerboard checkerboard.png</code></pre> 214 215<h5>STDIN, STDOUT, and file descriptors</h5> 216<p>Unix and Windows permit the output of one command to be piped to the input of another. ImageMagick permits image data to be read and written from the <a href="http://en.wikipedia.org/wiki/Standard_streams">standard streams</a> STDIN (<var>standard in</var>) and STDOUT (<var>standard out</var>), respectively, using a pseudo-filename of <code>-</code>. In this example we pipe the output of 217 <a href="magick.html">magick</a> to the <a href="display.html">display</a> program: 218</p> 219 220<pre class="highlight"><code>magick logo: gif:- | display gif:-</code></pre> 221 222<p>The second explicit format "<code>gif:</code>" is optional in the preceding example. The GIF image format has a unique signature within the image so ImageMagick's <a href="display.html">display</a> command can readily recognize the format as GIF. The <a href="magick.html">magick</a> program also accepts STDIN as input in this way: 223</p> 224 225<pre class="highlight"><code>magick rose: gif:- | magick - -resize "200%" bigrose.jpg'</code></pre> 226 227<p>Other pipes can be accessed via their <var>file descriptors</var> (as of version 6.4.9-3). The file descriptors 0, 1, and 2 are reserved for the standard streams STDIN, STDOUT, and STDERR, respectively, but a pipe associated with a file descriptor number <var>N</var>>2 can be accessed using the pseudonym <code>fd:</code><var>N</var>. (The pseudonyms <code>fd:0</code> and <code>fd:1</code> can be used for STDIN and STDOUT.) The next example shows how to append image data piped from files with descriptors 3 and 4 and direct the result to the file with descriptor number 5. 228</p> 229 230<pre class="highlight"><code>magick fd:3 fd:4 -append fd:5</code></pre> 231 232<p>When needed, explicit image formats can be given as mentioned earlier, as in the following. 233</p> 234 235<pre class="highlight"><code>magick gif:fd:3 jpg:fd:4 -append tif:fd:5</code></pre> 236 237<h5>Selecting Frames</h5> 238<p>Some images formats contain more than one image frame. Perhaps you only want the first image, or the last, or some number of images in-between. You can specify which image frames to read by appending the image filename with the frame range enclosed in brackets. Here our image (an animated GIF) contains more than one frame but we only want the first: 239</p> 240 241<pre class="highlight"><code>magick 'images.gif[0]' image.png</code></pre> 242 243<p class="text-info">Unix shells generally interpret brackets so we enclosed the filename in quotes above. 244In a Windows command shell the brackets are not interpreted but using quotes doesn't hurt. However, in most cases the roles of single-quotes and double-quotes are reversed with respect to Unix and Windows, so Windows users should usually try double-quotes where we display single-quotes, and vice versa. 245</p> 246 247<p>You can read more than one image from a sequence with a frame range. For example, you can extract the first four frames of an image sequence: 248</p> 249 250<pre class="highlight"><code>magick 'images.gif[0-3]' images.mng</code></pre> 251 252<p>The default is to step one frame at a time so frames 0, 1, 2, and 3 are returned. Set the step to 2 with <code>-define frames:step=2</code> and we instead get frames 0 and 2.</p> 253 254<p>Finally, you can read more than one image from a sequence, out-of-order. The next command gets the third image in the sequence, followed by the second, and then the fourth: 255</p> 256 257<pre class="highlight"><code>magick 'images.gif[3,2,4]' images.mng</code></pre> 258 259<p>Notice that in the last two commands, a single image is written. The output in this case, where the image type is MNG, is a multi-frame file because the MNG format supports multiple frames. Had the output format been JPG, which only supports single frames, the output would have consisted of separate frames. More about that below, in the section about the <a href="command-line-processing.html#output">Output Filename</a>. 260</p> 261 262<h5>Selecting an Image Region</h5> 263<p>Raw images are a sequence of color intensities without additional meta information such as width, height, or image signature. With raw image formats, you must specify the image width and height but you can also specify a region of the image to read. In our example, the image is in the raw 8-bit RGB format and is 6000 pixels wide and 4000 pixels high. However, we only want a region of 600 by 400 near the center of the image: 264</p> 265 266<pre class="highlight"><code>magick -size 6000x4000 -depth 8 'rgb:image[600x400+1900+2900]' image.jpg</code></pre> 267 268<p> 269 You can get the same results with the <a class="text-nowrap" href="command-line-options.html#extract">-extract</a> option: 270</p> 271 272<pre class="highlight"><code>magick -size 6000x4000 -depth 8 -extract 600x400+1900+2900 rgb:image image.jpg</code></pre> 273 274<h5>Inline Image Resize</h5> 275<p>It is sometimes convenient to resize an image as they are read. Suppose you have hundreds of large JPEG images you want to convert to a sequence of PNG thumbails: 276</p> 277 278<pre class="highlight"><code>magick '*.jpg' -resize 120x120 thumbnail%03d.png</code></pre> 279 280<p>Here <var>all</var> the images are read and subsequently 281resized. It is faster and less resource intensive to resize each image as it 282is read: 283</p> 284 285<pre class="highlight"><code>magick '*.jpg[120x120]' thumbnail%03d.png</code></pre> 286 287<h5>Inline Image Crop</h5> 288<p>It is sometimes convenient to crop an image as they are read. Suppose you have hundreds of large JPEG images you want to convert to a sequence of PNG thumbails: 289</p> 290 291<pre class="highlight"><code>magick '*.jpg' -crop 120x120+10+5 thumbnail%03d.png</code></pre> 292 293<p>Here <var>all</var> the images are read and subsequently cropped. It is faster and less resource-intensive to crop each image as it is read: 294</p> 295 296<pre class="highlight"><code>magick '*.jpg[120x120+10+5]' thumbnail%03d.png</code></pre> 297 298 299<h5>Filename References</h5> 300 301<p>There are two methods to use a filename to reference other image filenames. 302The first is with '<code>@</code>' which reads image filenames separated by white space from the specified file. Assume the file <code>myimages.txt</code> consists of a list of filenames, like so: 303</p> 304 305<pre class="highlight">frame001.jpg 306frame002.jpg 307frame003.jpg</pre> 308 309<p>We then expect this command:</p> 310 311<pre class="highlight"><code>magick @myimages.txt mymovie.gif</code></pre> 312 313<p>to read the images <code>frame001.jpg</code>, <code>frame002.jpg</code>, and <code>frame003.jpg</code> and convert them to a GIF image sequence. </p> 314<p>If the image path includes one or more spaces, enclose the path in quotes:</p> 315<pre class="highlight">'my title.jpg'</pre> 316 317 318 <p>Some ImageMagick command-line <a href="command-line-options.html">options</a> may exceed the capabilities of 319your command-line processor. Windows, for example, limits command-lines 320to 8192 characters. If, for example, you have a draw option with polygon 321points that exceed the command-line length limit, put the draw option instead 322in a file and reference the file with 323the <code>@</code> (e.g. <code>@mypoly.txt</code>).</p> 324 325<p>Another method of referring to other image files is by 326embedding a formatting character in the filename with a scene range. Consider 327the filename <code>image-%d.jpg[1-5]</code>. The command</p> 328 329<pre class="highlight"><code>magick image-%d.jpg[1-5]</code></pre> 330 331<p>causes ImageMagick to attempt to read images with these filenames: 332</p> 333 334<pre class="highlight">image-1.jpg 335image-2.jpg 336image-3.jpg 337image-4.jpg 338image-5.jpg</pre> 339 340<h5>Stream Buffering</h5> 341<p>By default, the input stream is buffered. To ensure information on the source file or terminal is read as soon as its available, set the buffer size to 0:</p> 342 343<pre class="highlight"><code>magick logo: gif:- | display -define stream:buffer-size=0 gif:-</code></pre> 344 345<h2><a class="anchor" id="option"></a>Command-line Options</h2> 346 347<p>You can direct the behavior of ImageMagick utilities with these command-line <a href="command-line-options.html">options</a>. The behavior of an option falls into one of these categories:</p> 348 349<ul> 350<li><a href="command-line-processing.html#setting">Image Setting</a></li> 351<li><a href="command-line-processing.html#operator">Image Operator</a></li> 352<li><a href="command-line-processing.html#channel">Image Channel Operator</a></li> 353<li><a href="command-line-processing.html#sequence">Image Sequence Operator</a></li> 354<li><a href="command-line-processing.html#geometry">Image Geometry</a></li> 355<li><a href="command-line-processing.html#stack">Image Stack</a></li> 356</ul> 357 358<h5><a class="anchor" id="setting"></a>Image Setting</h5> 359 360<p>An image setting persists as it appears on the command-line and may affect 361subsequent processing such as reading an image, an image operator, or when 362writing an image as appropriate. An image setting stays in effect until it 363is reset or the command-line terminates. The image settings include:</p> 364 365<ul> 366<a class="text-nowrap" href="command-line-options.html#adjoin">-adjoin</a> • <a class="text-nowrap" href="command-line-options.html#affine">-affine</a> • <a class="text-nowrap" href="command-line-options.html#alpha">-alpha</a> • <a class="text-nowrap" href="command-line-options.html#antialias">-antialias</a> • <a class="text-nowrap" href="command-line-options.html#authenticate">-authenticate</a> • <a class="text-nowrap" href="command-line-options.html#background">-background</a> • <a class="text-nowrap" href="command-line-options.html#bias">-bias</a> • <a class="text-nowrap" href="command-line-options.html#black-point-compensation">-black-point-compensation</a> • <a class="text-nowrap" href="command-line-options.html#blue-primary">-blue-primary</a> • <a class="text-nowrap" href="command-line-options.html#bordercolor">-bordercolor</a> • <a class="text-nowrap" href="command-line-options.html#caption">-caption</a> • <a class="text-nowrap" href="command-line-options.html#channel">-channel</a> • <a class="text-nowrap" href="command-line-options.html#comment">-comment</a> • <a class="text-nowrap" href="command-line-options.html#compress">-compress</a> • <a class="text-nowrap" href="command-line-options.html#debug">-debug</a> • <a class="text-nowrap" href="command-line-options.html#define">-define</a> • <a class="text-nowrap" href="command-line-options.html#delay">-delay</a> • <a class="text-nowrap" href="command-line-options.html#density">-density</a> • <a class="text-nowrap" href="command-line-options.html#depth">-depth</a> • <a class="text-nowrap" href="command-line-options.html#direction">-direction</a> • <a class="text-nowrap" href="command-line-options.html#display">-display</a> • <a class="text-nowrap" href="command-line-options.html#dispose">-dispose</a> • <a class="text-nowrap" href="command-line-options.html#dither">-dither</a> • <a class="text-nowrap" href="command-line-options.html#encoding">-encoding</a> • <a class="text-nowrap" href="command-line-options.html#endian">-endian</a> • <a class="text-nowrap" href="command-line-options.html#extract">-extract</a> • <a class="text-nowrap" href="command-line-options.html#family">-family</a> • <a class="text-nowrap" href="command-line-options.html#fill">-fill</a> • <a class="text-nowrap" href="command-line-options.html#filter">-filter</a> • <a class="text-nowrap" href="command-line-options.html#font">-font</a> • <a class="text-nowrap" href="command-line-options.html#format">-format</a> • <a class="text-nowrap" href="command-line-options.html#fuzz">-fuzz</a> • <a class="text-nowrap" href="command-line-options.html#geometry">-geometry</a> • <a class="text-nowrap" href="command-line-options.html#gravity">-gravity</a> • <a class="text-nowrap" href="command-line-options.html#green-primary">-green-primary</a> • <a class="text-nowrap" href="command-line-options.html#interlace">-interlace</a> • <a class="text-nowrap" href="command-line-options.html#intent">-intent</a> • <a class="text-nowrap" href="command-line-options.html#interpolate">-interpolate</a> • <a class="text-nowrap" href="command-line-options.html#label">-label</a> • <a class="text-nowrap" href="command-line-options.html#limit">-limit</a> • <a class="text-nowrap" href="command-line-options.html#linewidth">-linewidth</a> • <a class="text-nowrap" href="command-line-options.html#log">-log</a> • <a class="text-nowrap" href="command-line-options.html#loop">-loop</a> • <a class="text-nowrap" href="command-line-options.html#mattecolor">-mattecolor</a> • <a class="text-nowrap" href="command-line-options.html#monitor">-monitor</a> • <a class="text-nowrap" href="command-line-options.html#orient">-orient</a> • <a class="text-nowrap" href="command-line-options.html#page">-page</a> • <a class="text-nowrap" href="command-line-options.html#pointsize">-pointsize</a> • <a class="text-nowrap" href="command-line-options.html#preview">-preview</a> • <a class="text-nowrap" href="command-line-options.html#quality">-quality</a> • <a class="text-nowrap" href="command-line-options.html#quiet">-quiet</a> • <a class="text-nowrap" href="command-line-options.html#read-mask">-read-mask</a> • <a class="text-nowrap" href="command-line-options.html#red-primary">-red-primary</a> • <a class="text-nowrap" href="command-line-options.html#region">-region</a> • <a class="text-nowrap" href="command-line-options.html#render">-render</a> • <a class="text-nowrap" href="command-line-options.html#repage">-repage</a> • <a class="text-nowrap" href="command-line-options.html#sampling-factor">-sampling-factor</a> • <a class="text-nowrap" href="command-line-options.html#scene">-scene</a> • <a class="text-nowrap" href="command-line-options.html#seed">-seed</a> • <a class="text-nowrap" href="command-line-options.html#size">-size</a> • <a class="text-nowrap" href="command-line-options.html#stretch">-stretch</a> • <a class="text-nowrap" href="command-line-options.html#stroke">-stroke</a> • <a class="text-nowrap" href="command-line-options.html#strokewidth">-strokewidth</a> • <a class="text-nowrap" href="command-line-options.html#style">-style</a> • <a class="text-nowrap" href="command-line-options.html#texture">-texture</a> • <a class="text-nowrap" href="command-line-options.html#tile">-tile</a> • <a class="text-nowrap" href="command-line-options.html#transparent-color">-transparent-color</a> • <a class="text-nowrap" href="command-line-options.html#treedepth">-treedepth</a> • <a class="text-nowrap" href="command-line-options.html#type">-type</a> • <a class="text-nowrap" href="command-line-options.html#undercolor">-undercolor</a> • <a class="text-nowrap" href="command-line-options.html#units">-units</a> • <a class="text-nowrap" href="command-line-options.html#verbose">-verbose</a> • <a class="text-nowrap" href="command-line-options.html#virtual-pixel">-virtual-pixel</a> • <a class="text-nowrap" href="command-line-options.html#weight">-weight</a> • <a class="text-nowrap" href="command-line-options.html#write-mask">-write-mask</a> </ul> 367 368<p>In this example, <var>-channel</var> applies to each of the images, since, as we mentioned, settings persist: 369</p> 370 371<pre class="highlight"><code>magick -channel RGB wand.png wizard.png images.png</code></pre> 372 373<h5><a class="anchor" id="operator"></a>Image Operator</h5> 374 375<p>An image operator differs from a setting in that it affects the image 376immediately as it appears on the command-line. An operator is 377any command-line <a href="command-line-options.html">option</a> not listed as a 378<a href="command-line-processing.html#setting">image setting</a> or 379<a href="command-line-processing.html#sequence">image sequence operator</a>. Unlike an 380image setting, which persists until the command-line terminates, 381an operator is applied to the current image set and forgotten. The image operators include:</p> 382 383<ul> 384<a class="text-nowrap" href="command-line-options.html#annotate">-annotate</a> • <a class="text-nowrap" href="command-line-options.html#black-threshold">-black-threshold</a> • <a class="text-nowrap" href="command-line-options.html#blur">-blur</a> • <a class="text-nowrap" href="command-line-options.html#border">-border</a> • <a class="text-nowrap" href="command-line-options.html#charcoal">-charcoal</a> • <a class="text-nowrap" href="command-line-options.html#chop">-chop</a> • <a class="text-nowrap" href="command-line-options.html#clip">-clip</a> • <a class="text-nowrap" href="command-line-options.html#clip-path">-clip-path</a> • <a class="text-nowrap" href="command-line-options.html#clip-mask">-clip-mask</a> • <a class="text-nowrap" href="command-line-options.html#colors">-colors</a> • <a class="text-nowrap" href="command-line-options.html#colorize">-colorize</a> • <a class="text-nowrap" href="command-line-options.html#colorspace">-colorspace</a> • <a class="text-nowrap" href="command-line-options.html#color-threshold">-color-threshold</a> • <a class="text-nowrap" href="command-line-options.html#compose">-compose</a> • <a class="text-nowrap" href="command-line-options.html#contrast">-contrast</a> • <a class="text-nowrap" href="command-line-options.html#convolve">-convolve</a> • <a class="text-nowrap" href="command-line-options.html#crop">-crop</a> • <a class="text-nowrap" href="command-line-options.html#cycle">-cycle</a> • <a class="text-nowrap" href="command-line-options.html#despeckle">-despeckle</a> • <a class="text-nowrap" href="command-line-options.html#draw">-draw</a> • <a class="text-nowrap" href="command-line-options.html#edge">-edge</a> • <a class="text-nowrap" href="command-line-options.html#emboss">-emboss</a> • <a class="text-nowrap" href="command-line-options.html#enhance">-enhance</a> • <a class="text-nowrap" href="command-line-options.html#equalize">-equalize</a> • <a class="text-nowrap" href="command-line-options.html#evaluate">-evaluate</a> • <a class="text-nowrap" href="command-line-options.html#extent">-extent</a> • <a class="text-nowrap" href="command-line-options.html#flip">-flip</a> • <a class="text-nowrap" href="command-line-options.html#flop">-flop</a> • <a class="text-nowrap" href="command-line-options.html#floodfill">-floodfill</a> • <a class="text-nowrap" href="command-line-options.html#frame">-frame</a> • <a class="text-nowrap" href="command-line-options.html#gamma">-gamma</a> • <a class="text-nowrap" href="command-line-options.html#gaussian-blur">-gaussian-blur</a> • <a class="text-nowrap" href="command-line-options.html#grayscale">-grayscale</a> • <a class="text-nowrap" href="command-line-options.html#implode">-implode</a> • <a class="text-nowrap" href="command-line-options.html#kmeans">-kmeans</a> • <a class="text-nowrap" href="command-line-options.html#lat">-lat</a> • <a class="text-nowrap" href="command-line-options.html#level">-level</a> • <a class="text-nowrap" href="command-line-options.html#map">-map</a> • <a class="text-nowrap" href="command-line-options.html#median">-median</a> • <a class="text-nowrap" href="command-line-options.html#modulate">-modulate</a> • <a class="text-nowrap" href="command-line-options.html#monochrome">-monochrome</a> • <a class="text-nowrap" href="command-line-options.html#negate">-negate</a> • <a class="text-nowrap" href="command-line-options.html#noise">-noise</a> • <a class="text-nowrap" href="command-line-options.html#normalize">-normalize</a> • <a class="text-nowrap" href="command-line-options.html#opaque">-opaque</a> • <a class="text-nowrap" href="command-line-options.html#ordered-dither">-ordered-dither</a> • <a class="text-nowrap" href="command-line-options.html#paint">-paint</a> • <a class="text-nowrap" href="command-line-options.html#posterize">-posterize</a> • <a class="text-nowrap" href="command-line-options.html#raise">-raise</a> • <a class="text-nowrap" href="command-line-options.html#profile">-profile</a> • <a class="text-nowrap" href="command-line-options.html#radial-blur">-radial-blur</a> • <a class="text-nowrap" href="command-line-options.html#raise">-raise</a> • <a class="text-nowrap" href="command-line-options.html#random-threshold">-random-threshold</a> • <a class="text-nowrap" href="command-line-options.html#resample">-resample</a> • <a class="text-nowrap" href="command-line-options.html#resize">-resize</a> • <a class="text-nowrap" href="command-line-options.html#roll">-roll</a> • <a class="text-nowrap" href="command-line-options.html#rotate">-rotate</a> • <a class="text-nowrap" href="command-line-options.html#sample">-sample</a> • <a class="text-nowrap" href="command-line-options.html#scale">-scale</a> • <a class="text-nowrap" href="command-line-options.html#sepia-tone">-sepia-tone</a> • <a class="text-nowrap" href="command-line-options.html#segment">-segment</a> • <a class="text-nowrap" href="command-line-options.html#shade">-shade</a> • <a class="text-nowrap" href="command-line-options.html#shadow">-shadow</a> • <a class="text-nowrap" href="command-line-options.html#sharpen">-sharpen</a> • <a class="text-nowrap" href="command-line-options.html#shave">-shave</a> • <a class="text-nowrap" href="command-line-options.html#shear">-shear</a> • <a class="text-nowrap" href="command-line-options.html#sigmoidal-contrast">-sigmoidal-contrast</a> • <a class="text-nowrap" href="command-line-options.html#solarize">-solarize</a> • <a class="text-nowrap" href="command-line-options.html#splice">-splice</a> • <a class="text-nowrap" href="command-line-options.html#spread">-spread</a> • <a class="text-nowrap" href="command-line-options.html#strip">-strip</a> • <a class="text-nowrap" href="command-line-options.html#swirl">-swirl</a> • <a class="text-nowrap" href="command-line-options.html#threshold">-threshold</a> • <a class="text-nowrap" href="command-line-options.html#transparent">-transparent</a> • <a class="text-nowrap" href="command-line-options.html#thumbnail">-thumbnail</a> • <a class="text-nowrap" href="command-line-options.html#tint">-tint</a> • <a class="text-nowrap" href="command-line-options.html#transform">-transform</a> • <a class="text-nowrap" href="command-line-options.html#trim">-trim</a> • <a class="text-nowrap" href="command-line-options.html#unsharp">-unsharp</a> • <a class="text-nowrap" href="command-line-options.html#version">-version</a> • <a class="text-nowrap" href="command-line-options.html#wave">-wave</a> • <a class="text-nowrap" href="command-line-options.html#white-balance">-white-balance</a> • <a class="text-nowrap" href="command-line-options.html#white-point">-white-point</a> • <a class="text-nowrap" href="command-line-options.html#white-threshold">-white-threshold</a> </ul> 385 386<p>In this example, <var>-negate</var> negates the wand image but not the wizard:</p> 387 388<pre class="highlight"><code>magick wand.png -negate wizard.png images.png</code></pre> 389 390<p>Note that an image operator will be applied to each images in an image 391sequence. For example, if you use <a class="text-nowrap" href="command-line-options.html#resize">-resize</a> option to resize a 392GIF image, each frames will be resized to the given size. However, some frames 393may be smaller than the whole image and resizing all the frames into the same 394size may result in an unexpected output. In such a case, 395<a class="text-nowrap" href="command-line-options.html#coalesce">-coalesce</a> should be used to prepare those frames.</p> 396 397<h5<a class="anchor" id="channel"></a>Image Channel Operator</h5> 398<p>Operate directly on image channels:</p> 399<ul> 400<a class="text-nowrap" href="command-line-options.html#channel-fx">-channel-fx</a> • <a class="text-nowrap" href="command-line-options.html#separate">-separate</a> </ul> 401 402<h5><a class="anchor" id="sequence"></a>Image Sequence Operator</h5> 403 404<p>An image sequence operator differs from a setting in that it affects an 405image sequence immediately as it appears on the command-line. Choose from 406these image sequence operators:</p> 407 408<ul> 409<a class="text-nowrap" href="command-line-options.html#append">-append</a> • <a class="text-nowrap" href="command-line-options.html#affinity">-affinity</a> • <a class="text-nowrap" href="command-line-options.html#average">-average</a> • <a class="text-nowrap" href="command-line-options.html#clut">-clut</a> • <a class="text-nowrap" href="command-line-options.html#coalesce">-coalesce</a> • <a class="text-nowrap" href="command-line-options.html#combine">-combine</a> • <a class="text-nowrap" href="command-line-options.html#compare">-compare</a> • <a class="text-nowrap" href="command-line-options.html#complex">-complex</a> • <a class="text-nowrap" href="command-line-options.html#composite">-composite</a> • <a class="text-nowrap" href="command-line-options.html#copy">-copy</a> • <a class="text-nowrap" href="command-line-options.html#crop">-crop</a> • <a class="text-nowrap" href="command-line-options.html#debug">-debug</a> • <a class="text-nowrap" href="command-line-options.html#deconstruct">-deconstruct</a> • <a class="text-nowrap" href="command-line-options.html#delete">-delete</a> • <a class="text-nowrap" href="command-line-options.html#evaluate-sequence">-evaluate-sequence</a> • <a class="text-nowrap" href="command-line-options.html#fft">-fft</a> • <a class="text-nowrap" href="command-line-options.html#flatten">-flatten</a> • <a class="text-nowrap" href="command-line-options.html#fx">-fx</a> • <a class="text-nowrap" href="command-line-options.html#hald-clut">-hald-clut</a> • <a class="text-nowrap" href="command-line-options.html#ift">-ift</a> • <a class="text-nowrap" href="command-line-options.html#identify">-identify</a> • <a class="text-nowrap" href="command-line-options.html#insert">-insert</a> • <a class="text-nowrap" href="command-line-options.html#layers">-layers</a> • <a class="text-nowrap" href="command-line-options.html#limit">-limit</a> • <a class="text-nowrap" href="command-line-options.html#map">-map</a> • <a class="text-nowrap" href="command-line-options.html#maximum">-maximum</a> • <a class="text-nowrap" href="command-line-options.html#minimum">-minimum</a> • <a class="text-nowrap" href="command-line-options.html#morph">-morph</a> • <a class="text-nowrap" href="command-line-options.html#mosaic">-mosaic</a> • <a class="text-nowrap" href="command-line-options.html#optimize">-optimize</a> • <a class="text-nowrap" href="command-line-options.html#print">-print</a> • <a class="text-nowrap" href="command-line-options.html#process">-process</a> • <a class="text-nowrap" href="command-line-options.html#quiet">-quiet</a> • <a class="text-nowrap" href="command-line-options.html#swap">-swap</a> • <a class="text-nowrap" href="command-line-options.html#write">-write</a> </ul> 410<p>In this example, <var>-append</var> appends three images into one:</p> 411 412<pre class="highlight"><code>magick mikayla.png picnic.png beach.png -append vacation.png</code></pre> 413 414<h5"><a class="anchor" id="geometry"></a>Image Geometry</h5> 415 416<p>Many command-line <a href="command-line-options.html">options</a> take a <var>geometry</var> argument 417to specify such things as the desired width and height of an image and other 418dimensional quantities. Because users want so many variations on the resulting 419dimensions, sizes, and positions of images (and because ImageMagick wants to 420provide them), the <var>geometry</var> argument can take many 421forms. We describe many of these in this section. </p> 422 423<p>The image options and settings that take some form of 424a <var>geometry</var> argument include the following. 425Keep in mind that some of these parse their arguments in slightly 426different ways. See the documentation for the individual option or 427setting for more specifics.</p> 428 429<ul> 430<a class="text-nowrap" href="command-line-options.html#adaptive-resize">-adaptive-resize</a> • <a class="text-nowrap" href="command-line-options.html#border">-border</a> • <a class="text-nowrap" href="command-line-options.html#borderwidth">-borderwidth</a> • <a class="text-nowrap" href="command-line-options.html#chop">-chop</a> • <a class="text-nowrap" href="command-line-options.html#crop">-crop</a> • <a class="text-nowrap" href="command-line-options.html#density">-density</a> • <a class="text-nowrap" href="command-line-options.html#extent">-extent</a> • <a class="text-nowrap" href="command-line-options.html#extract">-extract</a> • <a class="text-nowrap" href="command-line-options.html#frame">-frame</a> • <a class="text-nowrap" href="command-line-options.html#geometry">-geometry</a> • <a class="text-nowrap" href="command-line-options.html#iconGeometry">-iconGeometry</a> • <a class="text-nowrap" href="command-line-options.html#liquid-rescale">-liquid-rescale</a> • <a class="text-nowrap" href="command-line-options.html#page">-page</a> • <a class="text-nowrap" href="command-line-options.html#region">-region</a> • <a class="text-nowrap" href="command-line-options.html#repage">-repage</a> • <a class="text-nowrap" href="command-line-options.html#resize">-resize</a> • <a class="text-nowrap" href="command-line-options.html#sample">-sample</a> • <a class="text-nowrap" href="command-line-options.html#scale">-scale</a> • <a class="text-nowrap" href="command-line-options.html#shave">-shave</a> • <a class="text-nowrap" href="command-line-options.html#splice">-splice</a> • <a class="text-nowrap" href="command-line-options.html#thumbnail">-thumbnail</a> • <a class="text-nowrap" href="command-line-options.html#window">-window</a> </ul> 431 432<p>The <var>geometry</var> argument might take any of the forms listed in the table below. These will described in more detail in the subsections following the table. The usual form is <var>size</var>[<var>offset</var>], meaning <var>size</var> is required and <var>offset</var> is optional. Occasionally, [<var>size</var>]<var>offset</var> is possible. In no cases are spaces permitted within the <var>geometry</var> argument.</p> 433 434 435<div class="table-responsive" style="font-size:87.5% !important;"> 436<table class="table table-sm table-hover"> 437 <col width="20%"/> <col width="80%"/> 438 <thead> 439 <tr> 440 <th style="text-align:center"><var>size</var></th> 441 <th>General description (actual behavior can vary for different options and settings)</th> 442 </tr> 443 </thead> 444 <tbody> 445 <tr> 446 <td><var>scale</var>%</td> 447 <td>Height and width both scaled by specified percentage.</td> 448 </tr> 449 <tr> 450 <td><var>scale-x</var>%x<var>scale-y</var>%</td> 451 <td>Height and width individually scaled by specified percentages. (Only one % symbol needed.)</td> 452 </tr> 453 <tr> 454 <td><var>width</var></td> 455 <td>Width given, height automagically selected to preserve aspect ratio.</td> 456 </tr> 457 <tr> 458 <td>x<var>height</var></td> 459 <td>Height given, width automagically selected to preserve aspect ratio.</td> 460 </tr> 461 <tr> 462 <td><var>width</var>x<var>height</var></td> 463 <td>Maximum values of height and width given, aspect ratio preserved.</td> 464 </tr> 465 <tr> 466 <td><var>width</var>x<var>height</var>^</td> 467 <td>Minimum values of width and height given, aspect ratio preserved.</td> 468 </tr> 469 <tr> 470 <td><var>width</var>x<var>height</var>!</td> 471 <td>Width and height emphatically given, original aspect ratio ignored.</td> 472 </tr> 473 <tr> 474 <td><var>width</var>x<var>height</var>></td> 475 <td>Shrinks an image with dimension(s) <b>larger</b> than the corresponding <var>width</var> and/or <var>height</var> argument(s).</td> 476 </tr> 477 <tr> 478 <td><var>width</var>x<var>height</var><</td> 479 <td>Enlarges an image with dimension(s) <b>smaller</b> than the corresponding <var>width</var> and/or <var>height</var> argument(s).</td> 480 </tr> 481 <tr> 482 <td><var>area</var>@</td> 483 <td>Resize image to have specified area in pixels. Aspect ratio is preserved.</td> 484 <tr> 485 <td><var>x</var>:<var>y</var></td> 486 <td>Here x and y denotes an aspect ratio (e.g. 3:2 = 1.5).</td> 487 </tr> 488 </tr> 489 <tr> 490 <td>{<var>size</var>}{<var>offset</var>}</td> 491 <td>Specifying the <var>offset</var> (default is <code>+0+0</code>). Below, {<var>size</var>} refers to any of the forms above.</td> 492 </tr> 493 <tr> 494 <td>{<var>size</var>}{<var>+-</var>}<var>x</var>{<var>+-</var>}<var>y</var></td> 495 <td>Horizontal and vertical offsets <var>x</var> and <var>y</var>, specified in pixels. Signs are required for both. Offsets are affected by <a class="text-nowrap" href="command-line-options.html#gravity">-gravity</a> setting. Offsets are not affected by <code>%</code> or other <var>size</var> operators. Note that positive X and Y offsets are in the inward direction towards the center of the image for all <a class="text-nowrap" href="command-line-options.html#gravity">-gravity</a> options, except 'center'. For East, +X is left. For South, +Y is up. For SouthEast, +X is left and +Y is up. For center, the normal X and Y directional convention is used (+X is right and +Y is down).</td> 496 </tr> 497 </tbody> 498</table></div> 499 500 501<h5>Basic adjustments to width and height; the operators <code>%</code>, <code>^</code>, and <code>!</code> </h5> 502<p>Here, just below, are a few simple examples of <var>geometry</var>, showing how it might be used as an argument to the <a class="text-nowrap" href="command-line-options.html#resize">-resize</a> option. We'll use the internal image <code>logo:</code> for our input image. 503<a href="../images/logo.png"> 504This fine image</a> is 640 pixels wide and 480 pixels high. We say its <var>dimensions</var> are 640x480. When we give dimensions of an image, the width (the horizontal dimension) always precedes the height (the vertical dimension). This will be true when we speak of coordinates or <var>offsets</var> into an image, which will always be <var>x</var>–value followed by <var>y</var>. Just think of your high school algebra classes and the <var>xy</var>–plane. (Well, almost: our <var>y</var>–axis will always go downward!) 505</p> 506 507<pre class="highlight"><code>magick logo: -resize '200%' bigWiz.png 508magick logo: -resize '200x50%' longShortWiz.png 509magick logo: -resize '100x200' notThinWiz.png 510magick logo: -resize '100x200^' biggerNotThinWiz.png 511magick logo: -resize '100x200!' dochThinWiz.png</code></pre> 512 513<p>The first of the four commands is simple—it stretches both the width and height of the input image by <code>200%</code> in each direction; it magnifies the whole thing by a factor of two. The second command specifies different percentages for each direction, stretching the width to <code>200</code>% and squashing the height to <code>50%</code>. The resulting image (in this example) has dimensions 1280x240. Notice that the percent symbol needn't be repeated; the following are equivalent: <code>200x50%</code>, <code>200%x50</code>, <code>200%x50%</code>. 514</p> 515 516<p>By default, the width and height given in a <var>geometry</var> argument are <var>maximum</var> values unless a percentage is specified. That is, the image is expanded or contracted to fit the specified width and height value while maintaining the <var>aspect ratio</var> (the ratio of its height to its width) of the image. For instance, the third command above "tries" to set the dimensions to <code>100x200</code>. Imagine gradually shrinking the original image (which is 640x480), keeping is aspect ratio constant, until it just fits into a 100x200 rectangle. Since the image is longer than it is tall, it will fit when its width shrinks to 100 pixels. To preserve the aspect ratio, the height will therefore have to be (480/640)×100 pixels=75 pixels, so the final dimensions will be 100x75.</p> 517 518<p> Notice that in the previous example, at least one of the specified dimensions will be attained (in this case, the width, 100 pixels). The resulting image fits snugly within the original. One can do just the opposite of this by invoking the <code>^</code> operator, as in the fourth example above. In that case, when <code>100x200^</code> is given as the argument, again at least one of the dimensions will be attained, but in this case the resulting image can snugly contain the original. Here the <var>geometry</var> argument gives <var>minimum</var> values. In our example, the height will become 200 and the width will be scaled to preserve the aspect ratio, becoming (640/480)×200 pixels=267 pixels. With the <code>^</code> operator, one of those dimensions will match the requested size, but the image will likely overflow the dimensions requested to preserve its aspect ratio. (The <code>^</code> feature is new as of IM 6.3.8-2.)</p> 519 520<p>We see that ImageMagick is very good about preserving aspect ratios of images, to prevent distortion of your favorite photos and images. But you might really want the dimensions to be <code>100x200</code>, thereby stretching the image. In this case just tell ImageMagick you really mean it (!) by appending an exclamation operator to the geometry. This will force the image size to exactly what you specify. So, for example, if you specify <code>100x200!</code> the dimensions will become exactly 100x200 (giving a small, vertically elongated wizard).</p> 521 522<h5>Bounding the width, height, and area; the operators <code>></code>, <code><</code>, and <code>@</code> </h5> 523<p> 524Here are a few more examples: 525</p> 526 527<pre class="highlight"><code>magick logo: -resize '100' wiz1.png 528magick logo: -resize 'x200' wiz2.png 529magick logo: -resize '100x200>' wiz3.png 530magick logo: -resize '100x200<' wiz4.png</code></pre> 531 532<p>If only one dimension is given it is taken to be the width. When only the width is specified, as in the first example above, the width is accepted as given and the height is chosen to maintain the aspect ratio of the input image. Similarly, if only the height is specified, as in the second example above, the height is accepted and the width is chosen to maintain the aspect ratio.</p> 533 534 535<p>Use <code>></code> to shrink an image <var>only</var> if its dimension(s) are <b>larger</b> than the corresponding <var>width</var> and/or <var>height</var> arguments. Use <code><</code> to enlarge an image <var>only</var> if its dimension(s) are <b>smaller</b> than the corresponding <var>width</var> and/or <var>height</var> arguments. In either case, if a change is made, the result is as if the <code>></code> or <code><</code> operator was not present. So, in the third example above, we specified <code>100x200></code> and the original image size is 640x480, so the image size is reduced as if we had specified <code>100x200</code>. However, in the fourth example above, there will be no change to its size.</p> 536 537<p>Finally, use <code>@</code> to specify the maximum area in pixels of an image, again while attempting to preserve aspect ratio. (Pixels take only integer values, so some approximation is always at work.) In the following example, an area of 10000 pixels is requested. The resulting file has dimensions 115x86, which has 9890 pixels. </p> 538 539<pre class="highlight"><code>magick logo: -resize '10000@' wiz10000.png</code></pre> 540 541<p class="text-info">In all the examples above and below, we have enclosed the <var>geometry</var> arguments within quotation marks. Doing so is optional in many cases, but not always. We <var>must</var> enclose the geometry specifications in quotation marks when using <code><</code> or <code>></code> to prevent these characters from being interpreted by the shell as <var>file redirection</var>. On Windows systems, the carat <code>^</code> needs to be within quotes, else it is ignored. To be safe, one should probably maintain a habit of enclosing all <var>geometry</var> arguments in quotes, as we have here. 542</p> 543 544<h5>Offsets in geometry</h5> 545<p> 546Here are some examples to illustrate the use of <var>offsets</var> in <var>geometry</var> arguments. One typical use of offsets is in conjunction with the 547<a class="text-nowrap" href="command-line-options.html#region">-region</a> option. This option allows many other options to modify the pixels within a specified rectangular subregion of an image. As such, it needs to be given the width and height of that region, and also an <var>offset</var> into the image, which is a pair of coordinates that indicate the location of the region within the larger image. Below, in the first example, we specify a region of size <code>100x200</code> to be located at the <var>xy</var>–coordinates <var>x</var>=10, <var>y</var>=20. Let's use the usual algebraic notation (<var>x</var>,<var>y</var>)=(10,20), for convenience. 548</p> 549 550<pre class="highlight"><code>magick logo: -region '100x200+10+20' -negate wizNeg1.png 551magick logo: -region '100x200-10+20' -negate wizNeg2.png 552magick logo: -gravity center -region '100x200-10+20' -negate wizNeg3.png</code></pre> 553 554<p>Note that offsets always require +/− signs. The offset is not actually a true location within the image; its coordinates must be added to some other location. Let's refer to that as the <var>current location</var>. In the first two examples above, though, that location is the upper-left hand corner of the image, which has coordinates (0,0). (That is the default situation when there are no other directives given to change it.) The first example above puts the <code>100x200</code> rectangle's own upper-left corner at (10,20). </p> 555 556<p>A negative offset can make sense in many cases. In the second example above, the offset is (-10,20), specified by <code>-10+20</code>. In that case, only the portion of the (virtual) rectangle obtained that lies within the image can be negated; here it is equivalent to specifying the geometry as <code>90x200+0+20</code>.</p> 557 558<p>In the third example above, the <a class="text-nowrap" href="command-line-options.html#gravity">-gravity</a> setting precedes the others and sets the current location within the image at the very center of the image. In this case that is at pixel (320,240), since the size of the image is 640x480. This means that the offsets apply to that location, which thereby gets moved, in this case, to (320-10,240+20)=(310,260). But the <code>100x200</code> region itself is affected by the <a class="text-nowrap" href="command-line-options.html#gravity">-gravity</a> setting, so instead of affecting its upper-left corner, the region's own center (at (+50,+100) within it) is determined. Therefore the center of the <code>100x200</code> rectangle is moved to (310,260). The negated rectangle's upper-left corner is now at (310-50,260-100)=(260,160). 559</p> 560 561 562<h5><a class="anchor" id="stack"></a>Image Stack</h5> 563 564<p>In school, your teacher probably permitted you to work on problems on a scrap of paper and then copy the results to your test paper. An image stack is similar. It permits you to work on an image or image sequence in isolation and subsequently introduce the results back into the command-line. The image stack is delineated with parenthesis. Image operators only affect images in the current stack. For example, we can limit the image rotation to just the wizard image like this:</p> 565 566<pre class="highlight"><code>magick wand.gif \( wizard.gif -rotate 30 \) +append images.gif</code></pre> 567 568 569<p class="text-info">Notice again that the parentheses are <var>escaped</var> by preceding them with 570backslashes. This is required under Unix, where parentheses are special 571<var>shell</var> characters. The backslash tells the shell not to interpret 572these characters, but to pass them directly to the command being executed. Do 573not escape the parentheses under Windows. Each parenthesis (or escaped 574parenthesis) must have spaces on either side, as in the example shown 575above.</p> 576 577<p>In addition to the image operators already discussed, the following image operators are most useful when processing images in an image stack:</p> 578 579<ul> 580<a class="text-nowrap" href="command-line-options.html#clone">-clone</a> • <a class="text-nowrap" href="command-line-options.html#delete">-delete</a> • <a class="text-nowrap" href="command-line-options.html#insert">-insert</a> • <a class="text-nowrap" href="command-line-options.html#swap">-swap</a> </ul> 581 582<p>The arguments to these operators are indexes into the image sequence by number, starting with zero, for the first image, and so on. However if you give a negative index, the images are indexed from the end (last image added). That is, an index of -1 is the last image in the current image sequence, -2 gives the second-to-last, and so on.</p> 583 584<h2><a class="anchor" id="output"></a>Output Filename</h2> 585 586<p>ImageMagick extends the concept of an output filename to include:</p> 587 588<ol> 589<li>an explicit image format</li> 590<li>write to <var>standard out</var></li> 591<li>filename references</li> 592</ol> 593 594<p>Each of these extensions are explained in the next few paragraphs.</p> 595 596<h5>Explicit Image Format</h5> 597 <p>Images can be stored in a mryiad of image formats including the better known JPEG, PNG, TIFF and others. ImageMagick must know the desired format of the image before it is written. ImageMagick leverages the filename extension to determine the format. For example, <code>image.jpg</code> tells ImageMagick to write the image in the JPEG format. In some cases the filename does not identify the image format. In these cases, the image is written in the format it was originally read unless an explicit image format is specified. For example, suppose we want to write our image to a filename of <code>image</code> in the raw red, green, and blue intensity format: 598 </p> 599 600<pre class="highlight"><code>magick image.jpg rgb:image</code></pre> 601 602 603<h5>Standard Out</h5> 604 <p>Unix permits the output of one command to be piped to another. ImageMagick permits piping one command to another with a filename of <code>-</code>. In this example we pipe the output of <a href="magick.html">magick</a> to the <a href="display.html">display</a> program: 605 </p> 606 607<pre class="highlight"><code>magick logo: gif:- | display gif:-</code></pre> 608 609<p>Here the explicit format is optional. The GIF image format has a signature that uniquely identifies it so ImageMagick can readily recognize the format as GIF.</p> 610 611<h5>Filename References</h5> 612<p>Optionally, use an embedded formatting character to write a sequential image list. Suppose our output filename is <code>image-%d.jpg</code> and our image list includes 3 images. You can expect these images files to be written: 613</p> 614 615<pre class="highlight">image-0.jpg 616image-1.jpg 617image-2.jpg</pre> 618 619<p>Or retrieve image properties to modify the image filename. For example, the command 620</p> 621 622<pre class="highlight"><code>magick rose: -set filename:area '%wx%h' 'rose-%[filename:area].png'</code></pre> 623 624<p>writes an image with this filename: 625</p> 626 627<pre class="highlight">rose-70x46.png</pre> 628 629<p>Finally to convert multiple JPEG images to individual PDF pages, use:</p> 630 631<pre class="highlight"><code>magick *.jpg +adjoin page-%d.pdf</code></pre> 632 633<h5>Stream Buffering</h5> 634 635<p>By default, the output stream is buffered. 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