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class='bull'> • </span> <a href="/www/command-line-options.html#lowlight-color">‑lowlight‑color</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#magnify">‑magnify</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#map">‑map</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#map_stream_">‑map[stream]</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#mask">‑mask</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#mattecolor">‑mattecolor</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#median">‑median</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#metric">‑metric</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#mode">‑mode</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#modulate">‑modulate</a> <span class='bull'> • </span> <a 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class='bull'> • </span> <a href="/www/command-line-options.html#ordered-dither">‑ordered‑dither</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#orient">‑orient</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#page">‑page</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#paint">‑paint</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#path">‑path</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#pause_animate_">‑pause[animate]</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#pause_import_">‑pause[import]</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#pen">‑pen</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#ping">‑ping</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#pointsize">‑pointsize</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#polaroid">‑polaroid</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#posterize">‑posterize</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#precision">‑precision</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#preview">‑preview</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#print">‑print</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#process">‑process</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#profile">‑profile</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#quality">‑quality</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#quantize">‑quantize</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#quiet">‑quiet</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#radial-blur">‑radial‑blur</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#raise">‑raise</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#random-threshold">‑random‑threshold</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#red-primary">‑red‑primary</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#regard-warnings">‑regard‑warnings</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#region">‑region</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#remap">‑remap</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#remote">‑remote</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#render">‑render</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#repage">‑repage</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#resample">‑resample</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#resize">‑resize</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#respect-parentheses">‑respect‑parentheses</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#reverse">‑reverse</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#roll">‑roll</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#rotate">‑rotate</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#sample">‑sample</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#sampling-factor">‑sampling‑factor</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#scale">‑scale</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#scene">‑scene</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#screen">‑screen</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#seed">‑seed</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#segment">‑segment</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#selective-blur">‑selective‑blur</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#separate">‑separate</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#sepia-tone">‑sepia‑tone</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#set">‑set</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#shade">‑shade</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#shadow">‑shadow</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#shared-memory">‑shared‑memory</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#sharpen">‑sharpen</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#shave">‑shave</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#shear">‑shear</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#sigmoidal-contrast">‑sigmoidal‑contrast</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#silent">‑silent</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#size">‑size</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#sketch">‑sketch</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#smush">‑smush</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#snaps">‑snaps</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#solarize">‑solarize</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#sparse-color">‑sparse‑color</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#splice">‑splice</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#spread">‑spread</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#statistic">‑statistic</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#stegano">‑stegano</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#stereo">‑stereo</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#stretch">‑stretch</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#strip">‑strip</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#stroke">‑stroke</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#strokewidth">‑strokewidth</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#style">‑style</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#subimage-search">‑subimage‑search</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#swap">‑swap</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#swirl">‑swirl</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#synchronize">‑synchronize</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#taint">‑taint</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#text-font">‑text‑font</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#texture">‑texture</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#threshold">‑threshold</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#thumbnail">‑thumbnail</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#tile">‑tile</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#tile-offset">‑tile‑offset</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#tint">‑tint</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#title">‑title</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#transform">‑transform</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#transparent">‑transparent</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#transparent-color">‑transparent‑color</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#transpose">‑transpose</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#transverse">‑transverse</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#treedepth">‑treedepth</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#trim">‑trim</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#type">‑type</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#undercolor">‑undercolor</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#unique-colors">‑unique‑colors</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#units">‑units</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#unsharp">‑unsharp</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#update">‑update</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#verbose">‑verbose</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#version">‑version</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#view">‑view</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#vignette">‑vignette</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#virtual-pixel">‑virtual‑pixel</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#visual">‑visual</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#watermark">‑watermark</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#wave">‑wave</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#weight">‑weight</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#white-point">‑white‑point</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#white-threshold">‑white‑threshold</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#window">‑window</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#window-group">‑window‑group</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#write">‑write</a> ] </p> 206 207<div class="doc-section"> 208 209<p>Below is list of command-line options recognized by the ImageMagick <a 210href="/www/command-line-tools.html">command-line 211tools</a>. If you want a description of a particular option, click on the 212option name in the navigation bar above and you will go right to it. Unless 213otherwise noted, each option is recognized by the commands <a href="/www/convert.html">convert</a>, <a href="/www/mogrify.html">mogrify</a>.</p> 214 215<div style="margin: auto;"> 216 <h4><a id="adaptive-blur"></a>-adaptive-blur <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4> 217</div> 218 219<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Adaptively blur pixels, with decreasing effect near edges.</td><td style='text-align:right;'></td></tr></table> 220<p>A Gaussian operator of the given radius and standard deviation (<em class="arg">sigma</em>) is used. If <em class="arg">sigma</em> is not given it defaults to 1.</p> 221 222<div style="margin: auto;"> 223 <h4><a id="adaptive-resize"></a>-adaptive-resize <em class="arg">geometry</em></h4> 224</div> 225 226<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Resize the image using data-dependent triangulation.</td><td style='text-align:right;'></td></tr></table> 227 228<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. The <a href="#adaptive-resize">-adaptive-resize</a> option defaults to data-dependent triangulation. Use the <a href="#filter">-filter</a> to choose a different resampling algorithm. Offsets, if present in the geometry string, are ignored, and the <a href="#gravity">-gravity</a> option has no effect.</p> 229 230<div style="margin: auto;"> 231 <h4><a id="adaptive-sharpen"></a>-adaptive-sharpen <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4> 232</div> 233 234<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Adaptively sharpen pixels, with increasing effect near edges.</td><td style='text-align:right;'></td></tr></table> 235 236<p>A Gaussian operator of the given radius and standard deviation (<em class="arg">sigma</em>) is used. If <em class="arg">sigma</em> is not given it defaults to 1.</p> 237 238<div style="margin: auto;"> 239 <h4><a id="adjoin"></a>-adjoin</h4> 240</div> 241 242<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Join images into a single multi-image file.</td><td style='text-align:right;'></td></tr></table> 243 244<p>This option is enabled by default. An attempt is made to save all images of 245an image sequence into the given output file. However, some formats, such as 246JPEG and PNG, do not support more than one image per file, and in that case 247ImageMagick is forced to write each image as a separate file. As such, if 248more than one image needs to be written, the filename given is modified by 249adding a <a href="#scene">-scene</a> number before the suffix, in order to 250make distinct names for each image. </p> 251 252<p>Use <a href="#adjoin">+adjoin</a> to force each image to be written to 253separate files, whether or not the file format allows multiple images per file 254(for example, GIF, MIFF, and TIFF). </p> 255 256<p>Including a C-style integer format string in the output filename will 257automagically enable <a href="#adjoin">+adjoin</a> and are used to specify 258where the <a href="#scene">-scene</a> number is placed in the filenames. These 259strings, such as '<kbd>%d</kbd>' or '<kbd>%03d</kbd>', are familiar to those 260who have used the standard <kbd>printf()</kbd>' C-library function. As an 261example, the command</p> 262 263<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert logo: rose: -morph 15 my%02dmorph.jpg</span></p> 264<p>will create a sequence of 17 images (the two given plus 15 more created by 265<a href="#morph">-morph</a>), named: my00morph.jpg, my01morph.jpg, 266my02morph.jpg, ..., my16morph.jpg. </p> 267 268<p>In summary, ImageMagick tries to write all images to one file, but will 269save to multiple files, if any of the following conditions exist... 270<ol> 271<li>the output image's file format does not allow multi-image files, 272<li>the <a href="#adjoin">+adjoin</a> option is given, or 273<li>a printf() integer format string (eg: "%d") is present in the output 274 filename. 275</ol></p> 276 277 278<div style="margin: auto;"> 279 <h4><a id="affine"></a>-affine 280 <em class="arg">s<sub>x</sub></em>,<em class="arg">r<sub>x</sub></em>,<em 281 class="arg">r<sub>y</sub></em>,<em class="arg">s<sub>y</sub></em>[,<em 282 class="arg">t<sub>x</sub></em>,<em class="arg">t<sub>y</sub></em>] 283</div> 284 285<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the drawing transformation matrix for combined rotating and scaling.</td><td style='text-align:right;'></td></tr></table> 286 287<p>This option sets a transformation matrix, for use by subsequent <a 288href="#draw">-draw</a> or <a href="#transform">-transform</a> options. </p> 289 290<p>The matrix entries are entered as comma-separated numeric values either in 291quotes or without spaces. </p> 292 293<p>Internally, the transformation matrix has 3x3 elements, but three of them 294are omitted from the input because they are constant. The new (transformed) 295coordinates (<em class="arg">x'</em>, <em class="arg">y'</em>) of a pixel at 296position (<em class="arg">x</em>, <em class="arg">y</em>) in the original 297image are calculated using the following matrix equation.</p> 298 299<div class="eqn"> 300<img alt="affine transformation" src="/images/affine.png"/> 301</div> 302 303<p> The size of the resulting image is that of the smallest rectangle that 304contains the transformed source image. The parameters <em 305class="arg">t<sub>x</sub></em> and <em class="arg">t<sub>y</sub></em> 306subsequently shift the image pixels so that those that are moved out of the 307image area are cut off.</p> 308 309<p>The transformation matrix complies with the left-handed pixel coordinate 310system: positive <em class="arg">x</em> and <em class="arg">y</em> directions 311are rightward and downward, resp.; positive rotation is clockwise.</p> 312 313<p> If the translation coefficients <em class="arg">t<sub>x</sub></em> and <em 314class="arg">t<sub>y</sub></em> are omotted they default to 0,0. Therefore, 315four parameters suffice for rotation and scaling without translation.</p> 316 317<p>Scaling by the factors <em class="arg">s<sub>x</sub></em> and <em 318class="arg">s<sub>y</sub></em> in the <em>x</em> and <em>y</em> directions, 319respectively, is accomplished with the following.</p> 320 321<p>See <a href="#transform">-transform</a>, and the <a 322href="#distort">-distort</a> method '<kbd>Affineprojection</kbd> for more 323information </p> 324 325 326<p class="crtsnip"> 327 -affine <em class="arg">s<sub>x</sub></em>,0,0,<em class="arg">s<sub>y</sub></em> 328</p> 329 330<p>Translation by a displacement (<em class="arg">t<sub>x</sub></em>, <em class="arg">t<sub>y</sub></em>) is accomplished like so:</p> 331 332<p class="crtsnip"> 333 -affine 1,0,0,1,<em class="arg">t<sub>x</sub></em>,<em class="arg">t<sub>y</sub></em> 334</p> 335 336<p>Rotate clockwise about the origin (the upper left-hand corner) by an angle <em>a</em> by letting 337<em>c</em> = cos(<em>a</em>), <em>s</em> = sin(<em>a</em>), and using the following.</p> 338 339<p class="crtsnip"> 340 -affine <em>c</em>,<em>s</em>,-<em>s</em>,<em>c</em> 341</p> 342 343<p>The cumulative effect of a sequence of <a href="#affine" >-affine</a> transformations can be accomplished by instead by a single <a href="#affine" >-affine</a> operation using the matrix equal to the product of the matrices of the individual transformations.</p> 344 345<p>An attempt is made to detect near-singular transformation matrices. If the matrix determinant has a sufficiently small absolute value it is rejected.</p> 346 347<div style="margin: auto;"> 348 <h4><a id="alpha"></a>-alpha <em class="arg">type</em></h4> 349</div> 350 351<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Gives control of the alpha/matte channel of an image.</td><td style='text-align:right;'></td></tr></table> 352 353<p>Used to set a flag on an image indicating whether or not to use existing alpha 354channel data, to create an alpha channel, or to perform other operations on the alpha channel. Choose the argument <em class="arg">type</em> from the list below.</p> 355 356 357<table class="doc"> 358 <tbody> 359 <tr valign="top"> 360 <th align="left" style="width: 8%">type</th> 361 <th align="left">Description</th> 362 </tr> 363 364 <tr valign="top"> 365 <td valign="top"><kbd>Activate</kbd> or <kbd>On</kbd></td> 366 <td valign="top"> 367 Enable the image's transparency channel. Note normally <kbd>Set</kbd> 368 should be used instead of this, unless you specifically need to 369 preserve existing (but specifically turned <kbd>Off</kbd>) transparency 370 channel. </td></tr> 371 372 <tr valign="top"> 373 <td valign="top"><kbd>Deactivate</kbd> or <kbd>Off</kbd></td> 374 <td valign="top"> 375 Disables the image's transparency channel. Does not delete or change the 376 existing data, just turns off the use of that data.</td></tr> 377 378 <tr valign="top"> 379 <td valign="top"><kbd>Set</kbd></td> 380 <td valign="top"> 381 Activates the alpha/matte channel. If it was previously turned off 382 then it also resets the channel to opaque. If the image already had 383 the alpha channel turned on, it will have no effect.</td></tr> 384 385 <tr valign="top"> 386 <td valign="top"><kbd>Opaque</kbd></td> 387 <td valign="top"> 388 Enables the alpha/matte channel and forces it to be fully opaque. 389 </td></tr> 390 391 <tr valign="top"> 392 <td valign="top"><kbd>Transparent</kbd></td> 393 <td valign="top"> 394 Activates the alpha/matte channel and forces it to be fully 395 transparent. This effectively creates a fully transparent image the 396 same size as the original and with all its original RGB data still 397 intact, but fully transparent. </td></tr> 398 399 <tr valign="top"> 400 <td valign="top"><kbd>Extract</kbd></td> 401 <td valign="top"> 402 Copies the alpha channel values into all the color channels and turns 403 '<kbd>Off</kbd>' the the image's transparency, so as to generate 404 a gray-scale mask of the image's shape. The alpha channel data is left 405 intact just deactivated. This is the inverse of '<kbd>Copy</kbd>'. 406 </td></tr> 407 408 <tr valign="top"> 409 <td valign="top"><kbd>Copy</kbd></td> 410 <td valign="top"> 411 Turns '<kbd>On</kbd>' the alpha/matte channel, then copies the 412 gray-scale intensity of the image, into the alpha channel, converting 413 a gray-scale mask into a transparent shaped mask ready to be colored 414 appropriately. The color channels are not modified. </td></tr> 415 416 <tr valign="top"> 417 <td valign="top"><kbd>Shape</kbd></td> 418 <td valign="top"> 419 As per '<kbd>Copy</kbd>' but also colors the resulting shape mask with 420 the current background color. That is the RGB color channels is 421 replaced, with appropriate alpha shape. 422 </td></tr> 423 424 <tr valign="top"> 425 <td valign="top"><kbd>Background</kbd></td> 426 <td valign="top"> 427 Set any fully-transparent pixel to the background color, while leaving 428 it fully-transparent. This can make some image file formats, such as 429 PNG, smaller as the RGB values of transparent pixels are more uniform, 430 and thus can compress better. 431 </td></tr> 432 </tbody> 433</table> 434 435<p>Note that while the <a href="#matte" >+matte</a> operation is the same as 436"<kbd><a href="#alpha" >-alpha</a> Off</kbd>", the <a href="#matte" 437>-matte</a> operation is the same as "<kbd><a href="#alpha" >-alpha</a> 438Set</kbd>" and not "<kbd><a href="#alpha" >-alpha</a> On</kbd>". </p> 439 440 441<div style="margin: auto;"> 442 <h4><a id="annotate"></a> 443 -annotate <em class="arg">degrees</em> <em class="arg">text</em><br /> 444 -annotate <em class="arg">Xdegrees</em>x<em class="arg">Ydegrees</em> <em class="arg">text</em><br /> 445 -annotate <em class="arg">Xdegrees</em>x<em class="arg">Ydegrees</em> {+-}<em class="arg">t<sub>x</sub></em>{+-}<em class="arg">t<sub>y</sub></em> <em class="arg">text</em></h4> 446</div> 447 448<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Annotate an image with text.</td><td style='text-align:right;'></td></tr></table> 449 450<p>This is a convenience for annotating an image with text. For more precise control over text annotations, use <a href="#draw">-draw</a>.</p> 451 452 453<p>The values <em class="arg">Xdegrees</em> and <em class="arg">Ydegrees</em> control the shears with respect to the , respectively, applied to the text, while <em class="arg">t<sub>x</sub></em> and <em class="arg">t<sub>y</sub></em> are offsets that give the location of the text relative to the upper left corner of the image.</p> 454 455<p>Using <a href="#annotate">-annotate</a> <em class="arg">degrees</em> or <a href="#annotate">-annotate</a> <em class="arg">degrees</em>x<em class="arg">degrees</em> produces an unsheared rotation of the text. The direction of the rotation is positive, which means a clockwise rotation if <em class="arg">degrees</em> is positive. (This conforms to the usual mathematical convention once it is realized that the positive <em>y</em>–direction is conventionally considered to be <em>downward</em> for images.)</p> 456 457<p>The new (transformed) coordinates (<em class="arg">x'</em>, <em class="arg">y'</em>) of a pixel at position (<em class="arg">x</em>, <em class="arg">y</em>) in the image are calculated using the following matrix equation.</p> 458<div class="eqn"><img alt="annotate transformation" src="/images/annotate.png"/></div> 459 460<p>If <em class="arg">t<sub>x</sub></em> and <em class="arg">t<sub>y</sub></em> are omitted, they default to 0. This makes the bottom-left of the text becomes the upper-left corner of the image, which is probably undesirable. Adding a <a href="#gravity" >-gravity</a> option in this case leads to nice results.</p> 461 462<p>Text is any UTF-8 encoded character sequence. If <em class="arg">text</em> is of the form '@mytext.txt', the text is read from the file <kbd>mytext.txt</kbd>. Text in a file is taken literally; no embedded formatting characters are recognized.</p> 463 464<div style="margin: auto;"> 465 <h4><a id="antialias"></a>-antialias</h4> 466</div> 467 468<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Enable/Disable of the rendering of anti-aliasing pixels when 469drawing fonts and lines.</td><td style='text-align:right;'></td></tr></table> 470 471<p>By default, objects (e.g. text, lines, polygons, etc.) are antialiased when 472drawn. Use <a href="#antialias">+antialias</a> to disable the addition of 473antialiasing edge pixels. This will then reduce the number of colors added to 474an image to just the colors being directly drawn. That is, no mixed colors 475are added when drawing such objects. </p> 476 477<div style="margin: auto;"> 478 <h4><a id="append"></a>-append</h4> 479</div> 480 481<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Join current images vertically or horizontally.</td><td style='text-align:right;'></td></tr></table> 482 483<p>This option creates a single longer image image, by joining all the current 484images in sequence top-to-bottom. Use <a href="#append">+append</a> to 485stack images left-to-right. </p> 486 487<p>If they are not of the same width, narrower images are padded with the 488current <a href="#background">-background</a> color setting, and their 489position relative to each other can be controlled by the current <a 490href="#gravity">-gravity</a> setting. </p> 491 492 493<div style="margin: auto;"> 494 <h4><a id="attenuate"></a>-attenuate <em class="arg">value</em></h4> 495</div> 496 497<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Lessen (or intensify) when adding noise to an image.</td><td style='text-align:right;'></td></tr></table> 498 499 500<div style="margin: auto;"> 501 <h4><a id="authenticate"></a>-authenticate <em class="arg">password</em></h4> 502</div> 503 504<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Decrypt a PDF with a password.</td><td style='text-align:right;'></td></tr></table> 505 506<p>Use this option to supply a <em class="arg">password</em> for decrypting a PDF that has been encrypted using Microsoft Crypto API (MSC API). The encrypting using the MSC API is not supported.</p> 507 508<p>For a different encryption method, see <a href="#encipher">-encipher</a> and <a href="#decipher">-decipher</a>. </p> 509 510 511 512<div style="margin: auto;"> 513 <h4><a id="auto-gamma"></a>-auto-gamma</h4> 514</div> 515 516<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Automagically adjust gamma level of image.</td><td style='text-align:right;'></td></tr></table> 517 518<p>This calculates the mean values of an image, then applies a calculated <a 519href="#gamma" >-gamma</a> adjustment so that is the mean color exists in the 520image it will get a have a value of 50%. </p> 521 522<p>This means that any solid 'gray' image becomes 50% gray. </p> 523 524<p>This works well for real-life images with little or no extreme dark and 525light areas, but tend to fail for images with large amounts of bright sky or 526dark shadows. It also does not work well for diagrams or cartoon like images. 527</p> 528 529<p>It uses the <a href="#channel" >-channel</a> setting, (including the 530'<em>sync</em>' flag for channel syncronization), to determine which color 531values is used and modified. As the default <a href="#channel" 532>-channel</a> setting is '<em>RGB,sync</em>', channels are modified 533together by the same gamma value, preserving colors. </p> 534 535 536 537<div style="margin: auto;"> 538 <h4><a id="auto-level"></a>-auto-level</h4> 539</div> 540 541<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Automagically adjust color levels of image.</td><td style='text-align:right;'></td></tr></table> 542 543<p>This is a 'perfect' image normalization operator. It finds the exact 544minimum and maximum color values in the image and then applies a <a 545href="#level" >-level</a> operator to stretch the values to the full range of 546values. </p> 547 548<p>The operator is not typically used for real-life images, image scans, or 549JPEG format images, as a single 'out-rider' pixel can set a bad min/max values 550for the <a href="#level" >-level</a> operation. On the other hand it is the 551right operator to use for color stretching gradient images being used to 552generate Color lookup tables, distortion maps, or other 'mathematically' 553defined images. </p> 554 555<p>The operator is very similar to the <a href="#normalize">-normalize</a>, <a 556href="#contrast-stretch" >-contrast-stretch</a>, and <a href="#linear-stretch" 557>-linear-stretch</a> operators, but without 'histogram binning' or 'clipping' 558problems that these operators may have. That is <a href="#auto-level" 559>-auto-level</a> is the perfect or ideal version these operators. </p> 560 561<p>It uses the <a href="#channel" >-channel</a> setting, (including the 562special '<em>sync</em>' flag for channel syncronization), to determine 563which color values are used and modified. As the default <a 564href="#channel" >+channel</a> setting is '<em>RGB,sync</em>', the 565'<em>sync</em>' ensures that the color channels will are modified 566together by the same gamma value, preserving colors, and ignoring 567transparency. </p> 568 569 570<div style="margin: auto;"> 571 <h4><a id="auto-orient"></a>-auto-orient</h4> 572</div> 573 574<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Automagically orient (rotate) an image created by a digital camera.</td><td style='text-align:right;'></td></tr></table> 575 576<p>This operator reads and resets the EXIF image profile setting 'Orientation' 577and then performs the appropriate 90 degree rotation on the image to orient 578the image, for correct viewing. </p> 579 580<p>This EXIF profile setting is usually set using a gravity sensor in digital 581camara, however photos taken directly downward or upward may not have an 582appropriate value. Also images that have been orientation 'corrected' without 583reseting this setting, may be 'corrected' again resulting in a incorrect 584result. If the he EXIF profile was previously stripped, the <a 585href="#auto-orient" >-auto-orient</a> operator will do nothing. </p> 586 587 588<div style="margin: auto;"> 589 <h4><a id="average"></a>-average</h4> 590</div> 591 592<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Average a set of images.</td><td style='text-align:right;'></td></tr></table> 593 594<p>An error results if the images are not identically sized.</p> 595 596 597<div style="margin: auto;"> 598 <h4><a id="backdrop"></a>-backdrop</h4> 599</div> 600 601<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Display the image centered on a backdrop.</td><td style='text-align:right;'>[<a href="/www/animate.html">animate</a>, <a href="/www/display.html">display</a>]</td></tr></table> 602 603<p>This backdrop covers the entire workstation screen and is useful for hiding other X window activity while viewing the image. The color of the backdrop is specified as the background color. The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 604 605<div style="margin: auto;"> 606 <h4><a id="background"></a>-background <em class="arg">color</em></h4> 607</div> 608 609<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the background color.</td><td style='text-align:right;'></td></tr></table> 610 611<p>The color is specified using the format described under the <a href="#fill">-fill</a> option. The default background color (if none is specified or found in the image) is white.</p> 612 613<div style="margin: auto;"> 614 <h4><a id="bench"></a>-bench <em class="arg">iterations</em></h4> 615</div> 616 617<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Measure performance.</td><td style='text-align:right;'></td></tr></table> 618 619<p>Repeat the entire command for the given number of <em class="arg">iterations</em> and report the user-time and elapsed time. For instance, consider the following command and its output. Modify the benchmark with the -duration to run the benchmark for a fixed number of seconds and -concurrent to run the benchmark in parallel (requires the OpenMP feature).</p> 620 621<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert logo: -resize 1000% -bench 5 logo.png</span><span class='crtout'>Performance: 5i 0.875657ips 6.880u 0:05.710</span></p> 622<p>In this example, 5 iterations were completed at 0.875657 iterations per second, using 6.88 seconds of the user's allotted time, for a total elapsed time of 5.71 seconds.</p> 623 624<div style="margin: auto;"> 625 <h4><a id="bias"></a>-bias <em class="arg">value</em>{<em class="arg">%</em>}</h4> 626</div> 627 628<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Add bias when convolving an image.</td><td style='text-align:right;'></td></tr></table> 629 630<p>This option shifts the output of <a href="/www/command-line-options.html#convolve">‑convolve</a> so that positive and negative results are relative to the specified bias value. </p> 631 632<p>This is important for non-HDRI compilations of ImageMagick when dealing with convolutions that contain negative as well as positive values. This is especially the case with convolutions involving high pass filters or edge detection. Without an output bias, the negative values are clipped at zero.</p> 633 634<p>When using an ImageMagick with the HDRI compile-time setting, <a href="/www/command-line-options.html#bias">‑bias</a> is not needed, as ImageMagick is able to store/handle any 635negative results without clipping to the color value range 636(0..QuantumRange).</p> 637 638<p>See the discussion on HDRI implementations of ImageMagick on the page 639<a href="/www/high-dynamic-range.html">High Dynamic-Range Images</a>. For more about HDRI go the ImageMagick <a href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this <a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a> entry. 640</p> 641 642<div style="margin: auto;"> 643 <h4><a id="black-point-compensation"></a>-black-point-compensation</h4> 644</div> 645 646<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Use black point compensation.</td><td style='text-align:right;'></td></tr></table> 647 648<div style="margin: auto;"> 649 <h4><a id="black-threshold"></a>-black-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 650</div> 651 652<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Force to black all pixels below the threshold while leaving all pixels at or above the threshold unchanged.</td><td style='text-align:right;'></td></tr></table> 653 654<p> The threshold value can be given as a percentage or as an absolute integer value within [0, <em class="QR">QuantumRange</em>] corresponding to the desired <a href="/www/command-line-options.html#channel">‑channel</a> value. See <a href="/www/command-line-options.html#threshold">‑threshold</a> for more details on thresholds and resulting values. 655</p> 656 657 658<div style="margin: auto;"> 659 <h4><a id="blend"></a>-blend <em class="arg">geometry</em></h4> 660</div> 661 662<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>blend an image into another by the given absolute value or percent.</td><td style='text-align:right;'>[<a href="/www/composite.html">composite</a>]</td></tr></table> 663 664<p>Blend will average the images together ('plus') according to the 665percentages given and each pixels transparency. If only a single percentage 666value is given it sets the weight of the composite or 'source' image, while 667the background image is weighted by the exact opposite amount. That is a 668<kbd>-blend 30%</kbd> merges 30% of the 'source' image with 70% of the 669'destination' image. Thus it is equivalent to <kbd>-blend 30x70%</kbd>.</p> 670 671 672<div style="margin: auto;"> 673 <h4><a id="blue-primary"></a>-blue-primary <em class="arg">x</em>,<em class="arg">y</em></h4> 674</div> 675 676<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the blue chromaticity primary point.</td><td style='text-align:right;'></td></tr></table> 677 678<div style="margin: auto;"> 679 <h4><a id="blue-shift"></a>-blue-shift <em class="arg">factor</em></h4> 680</div> 681 682<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>simulate a scene at nighttime in the moonlight. Start with a factor of 1.5</td><td style='text-align:right;'></td></tr></table> 683 684<div style="margin: auto;"> 685 686<div style="margin: auto;"> 687 <h4><a id="blur"></a>-blur <em class="arg">radius</em><br />-blur <em class="arg">radius</em>x<em class="arg">sigma</em></h4> 688</div> 689 690<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Reduce image noise and reduce detail levels.</td><td style='text-align:right;'></td></tr></table> 691 692<p>Convolve the image with a Gaussian or normal distribution using the given 693<em class="arg" >Sigma</em> value. The formula is:</p> 694 695<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="/images/gaussian-blur.png"/> 696</div> 697 698<p>The <em class="arg" >Sigma</em> value is the important argument, and 699determines the actual amount of blurring that will take place. </p> 700 701<p>The <em class="arg" >Radius</em> is only used to determine the size of the 702array which will hold the calculated Gaussian distribution. It should be an 703integer. If not given, or set to zero, IM will calculate the largest possible 704radius that will provide meaningful results for the Gaussian distribution. 705</p> 706 707<p>The larger the <em class="arg" >Radius</em> the radius the slower the 708operation is. However too small a <em class="arg" >Radius</em>, and sever 709aliasing effects may result. As a guideline, <em class="arg" >Radius</em> 710should be at least twice the <em class="arg" >Sigma</em> value, though three 711times will produce a more accurite result. </p> 712 713<p>This option differs from <a href="#gaussian-blur">-gaussian-blur</a> simply 714by taking advantage of the separability properties of the distribution. Here 715we apply a single-dimensional Gaussian matrix in the horizontal direction, 716then repeat the process in the vertical direction.</p> 717 718<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 719pixels which are outside the image proper are blurred into the final result. 720</p> 721 722 723<div style="margin: auto;"> 724 <h4>-blur <em class="arg">Width</em>[x<em class="arg">Height</em>[+<em class="arg">Angle</em>]]</h4> 725</div> 726 727<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Variably blur and image according to the overlay mapping.</td><td style='text-align:right;'>[<a href="/www/composite.html">composite</a>]</td></tr></table> 728 729<p>Each pixel in the overlaid region is replaced with an Elliptical Weighted 730Average (EWA) of the source image, scaled according to the grayscale 731mapping. </p> 732 733<p>The ellipse is weighted with sigma set to the given <em class="arg" 734>Width</em> and <em class="arg" >Height</em>. The <em class="arg" >Height</em> 735defaults to the <em class="arg" >Width</em> for a normal circular Guassian 736weighting. The <em class="arg" >Angle</em> will rotate the ellipse from 737horizontal clock-wise. </p> 738 739<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 740pixels which are outside the image proper are blurred into the final result. 741</p> 742 743 744<div style="margin: auto;"> 745 <h4><a id="border"></a>-border <em class="arg">geometry</em></h4> 746</div> 747 748<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Surround the image with a border of color. </td><td style='text-align:right;'></td></tr></table> 749 750<p>Set the width and height using the <em class="arg">size</em> portion of the 751<em class="arg">gravity</em> argument. See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. Offsets are 752ignored. </p> 753 754<p>Set the border color by preceding with the <a 755href="#bordercolor">-bordercolor</a> setting.</p> 756 757<p>The <a href="#border">-border</a> operation is affected by the current <a 758href="#compose">-compose</a> setting and assumes that this is using the default 759'<kbd>Over</kbd>' composition method. It generates a image of the appropriate 760size colors by the current <a href="#bordercolor">-bordercolor</a> before 761overlaying the original image in the center of this net image. This means that 762with the default compose method of '<kbd>Over</kbd>' any transparent parts may 763be replaced by the current <a href="#bordercolor">-bordercolor</a> setting.</p> 764<p>See also the <a href="#frame">-frame</a> option, which has more 765functionality.</p> 766 767<div style="margin: auto;"> 768 <h4><a id="bordercolor"></a>-bordercolor <em class="arg">color</em></h4> 769</div> 770 771<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the border color.</td><td style='text-align:right;'></td></tr></table> 772 773<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 774 775<p>The default border color is <kbd>#DFDFDF</kbd>, <span style="background-color: #dfdfdf;">this shade of gray</span>.</p> 776 777<div style="margin: auto;"> 778 <h4><a id="borderwidth"></a>-borderwidth <em class="arg">geometry</em> </h4> 779</div> 780 781<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the border width.</td><td style='text-align:right;'>[<a href="/www/animate.html">animate</a>, <a href="/www/display.html">display</a>]</td></tr></table> 782 783<div style="margin: auto;"> 784 <h4><a id="brightness-contrast"></a>-brightness-contrast <em class="arg">brightness</em><br />-brightness-contrast <em class="arg">brightness</em>{x<em class="arg">contrast</em>}{<em class="arg">%</em>}}</h4> 785</div> 786 787<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Adjust the brightness and/or contrast of the image.</td><td style='text-align:right;'></td></tr></table> 788 789<p>Brightness and Contrast values apply changes to the input image. They are 790not absolute settings. A brightness or contrast value of zero means no change. 791The range of values is -100 to +100 on each. Positive values increase the 792brightness or contrast and negative values decrease the brightness or contrast. 793To control only contrast, set the brightness=0. To control only brightness, 794set contrast=0 or just leave it off.</p> 795 796<p>You may also use <a href="#fill">-channel</a> to control which channels to 797apply the brightness and/or contrast change. The default is to apply the same 798transformation to all channels.</p> 799 800<p>Brightness and Contrast arguments are converted to offset and slope of a 801linear transform and applied 802using <a href="#fill">-function polynomial "slope,offset"</a>.</p> 803 804<p>The slope varies from 0 at contrast=-100 to almost vertical at 805contrast=+100. For brightness=0 and contrast=-100, the result are totally 806midgray. For brightness=0 and contrast=+100, the result will approach but 807not quite reach a threshold at midgray; that is the linear transformation 808is a very steep vertical line at mid gray.</p> 809 810<p>Negative slopes, i.e. negating the image, are not possible with this 811function. All achievable slopes are zero or positive.</p> 812 813<p>The offset varies from -0.5 at brightness=-100 to 0 at brightness=0 to +0.5 814at brightness=+100. Thus, when contrast=0 and brightness=100, the result is 815totally white. Similarly, when contrast=0 and brightness=-100, the result is 816totally black.</p> 817 818<p>As the range of values for the arguments are -100 to +100, adding the '%' 819symbol is no different than leaving it off.</p> 820 821<div style="margin: auto;"> 822 <h4><a id="cache"></a>-cache <em class="arg">threshold</em></h4> 823</div> 824 825<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>(This option has been replaced by the <a href='#limit'>-limit</a> option.)</td><td style='text-align:right;'></td></tr></table> 826 827<div style="margin: auto;"> 828 <h4><a id="caption"></a>-caption <em class="arg">string</em></h4> 829</div> 830 831<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Assign a caption to an image.</td><td style='text-align:right;'></td></tr></table> 832 833<p>This option sets the caption meta-data of an image read in after this 834option has been given. To modify a caption of images already in memory use 835"<kbd><a href="#set">-set</a> caption</kbd>". </p> 836 837<p>The caption can contain special format characters listed in the <a 838href="/www/escape.html">Format and 839Print Image Properties</a>. These attributes are expanded when the caption 840is finally assigned to the individual images. </p> 841 842<p>If the first character of <em class="arg">string</em> is <em 843class="arg">@</em>, the image caption is read from a file titled by the 844remaining characters in the string. Comments read in from a file are literal; 845no embedded formatting characters are recognized.</p> 846 847<p>Caption meta-data ais not visible on the image itself. To do that use the 848<a href="#annotate">-annotate</a> or <a href="#draw">-draw</a> options 849instead.</p> 850 851<p>For example,</p> 852 853<p class="crtsnip"> 854 -caption "%m:%f %wx%h" bird.miff 855</p> 856 857<p>produces an image caption of <kbd>MIFF:bird.miff 512x480</kbd> (assuming 858that the image <kbd>bird.miff</kbd> has a width of 512 and a height of 859480.</p> 860 861 862<div style="margin: auto;"> 863 <h4><a id="cdl"></a>-cdl <em class="arg">filename</em></h4> 864</div> 865 866<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>color correct with a color decision list.</td><td style='text-align:right;'></td></tr></table> 867 868<p>Here is an example color correction collection:</p> 869 870<pre class="text"> 871<?xml version="1.0" encoding="UTF-8"?> 872<ColorCorrectionCollection xmlns="urn:ASC:CDL:v1.2"> 873 <ColorCorrection id="cc06668"> 874 <SOPNode> 875 <Slope> 0.9 1.2 0.5 </Slope> 876 <Offset> 0.4 -0.5 0.6 </Offset> 877 <Power> 1.0 0.8 1.5 </Power> 878 </SOPNode> 879 <SATNode> 880 <Saturation> 0.85 </Saturation> 881 </SATNode> 882 </ColorCorrection> 883</ColorCorrectionCollection> 884</pre> 885 886<div style="margin: auto;"> 887 <h4><a id="channel"></a>-channel <em class="arg">type</em></h4> 888</div> 889 890<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specify those image color channels to which subsequent operators are limited.</td><td style='text-align:right;'></td></tr></table> 891 892<p>Choose from: <kbd>Red</kbd>, <kbd>Green</kbd>, <kbd>Blue</kbd>, 893<kbd>Alpha</kbd>, <kbd>Cyan</kbd>, <kbd>Magenta</kbd>, <kbd>Yellow</kbd>, 894<kbd>Black</kbd>, <kbd>Opacity</kbd>, <kbd>Index</kbd>, <kbd>RGB</kbd>, 895<kbd>RGBA</kbd>, <kbd>CMYK</kbd>, or <kbd>CMYKA</kbd>.</p> 896 897<p>The channels above can also be specified as a comma-separated list or can be 898abbreviated as a concatenation of the letters '<kbd>R</kbd>', '<kbd>G</kbd>', 899'<kbd>B</kbd>', '<kbd>A</kbd>', '<kbd>O</kbd>', '<kbd>C</kbd>', 900'<kbd>M</kbd>', '<kbd>Y</kbd>', '<kbd>K</kbd>'. 901 902For example, to only select the <kbd>Red</kbd> and <kbd>Blue</kbd> channels 903you can either use </p> 904<p class="crtsnip"> 905 -channel Red,Blue 906</p> 907<p>or you can use the short hand form</p> 908<p class="crtsnip"> 909 -channel RB 910</p> 911 912<p>All the channels that is present in an image can be specified using the 913special channel type <kbd>All</kbd>. Not all operators are 'channel capable', 914but generally any operators that are generally 'grey-scale' image operators, 915will understand this setting. See individual operator documentation. </p> 916 917<br /> 918 919<p>On top of the normal channel selection a extra flag can be specified, 920'<kbd>Sync</kbd>'. This is turned on by default and if set means that 921operators that understand this flag should perform: cross-channel 922syncronization of the channels. If not specified, then most grey-scale 923operators will apply their image processing operations to each individual 924channel (as specified by the rest of the <a href="#channel">-channel</a> 925setting) completely independently from each other. </p> 926 927<p>For example for operators such as <a href="#auto-level">-auto-level</a> and 928<a href="#auto-gamma">-auto-gamma</a> the color channels are modified 929together in exactly the same way so that colors will remain in-sync. Without 930it being set, then each channel is modified separately and 931independently, which may produce color distortion. </p> 932 933<p>The <a href="#morphology">-morphology</a> '<kbd>Convolve</kbd>' method 934and the <a href="#compose">-compose</a> mathematical methods, also understands 935the '<kbd>Sync</kbd>' flag to modify the behaviour of pixel colors according 936to the alpha channel (if present). That is to say it will modify the image 937processing with the understanding that fully-transparent colors should not 938contribute to the final result. </p> 939 940<p>Basically, by default, operators work with color channels in syncronous, and 941treats transparency as special, unless the <a href="#channel">-channel</a> 942setting is modified so as to remove the effect of the '<kbd>Sync</kbd>' flag. 943How each operator does this depends on that operators current implementation. 944Not all operators understands this flag at this time, but that is changing. 945</p> 946 947<p>To print a complete list of channel types, use <a href="#list">-list 948channel</a>.</p> 949 950<br /> 951 952<p>By default, ImageMagick sets <a href="#channel">-channel</a> to the value 953'<kbd>RGBK,sync</kbd>', which specifies that operators act on all color 954channels except the transparency channel, and that all the color channels are 955to be modified in exactly the same way, with a understanding of transprancy 956(depending on the operation being applied). The 'plus' form <a 957href="#channel" >+channel</a> will reset the value back to this default. </p> 958 959<p>Options that are affected by the <a href="#channel" >-channel</a> setting 960include the following. 961 962<a href="#auto-gamma">-auto-gamma</a>, 963<a href="#auto-level">-auto-level</a>, 964<a href="#black-threshold">-black-threshold</a>, 965<a href="#blur">-blur</a>, 966<a href="#clamp">-clamp</a>, 967<a href="#clut">-clut</a>, 968<a href="#combine">-combine</a>, 969<a href="#composite">-composite</a> (Mathematical compose methods only), 970<a href="#convolve">-convolve</a>, 971<a href="#contrast-stretch">-contrast-stretch</a>, 972<a href="#evaluate">-evaluate</a>, 973<a href="#function">-function</a>, 974<a href="#fx">-fx</a>, 975<a href="#gaussian-blur">-gaussian-blur</a>, 976<a href="#hald-clut">-hald-clut</a>, 977<a href="#motion-blur">-motion-blur</a>, 978<a href="#morphology">-morphology</a>, 979<a href="#negate">-negate</a>, 980<a href="#normalize">-normalize</a>, 981<a href="#ordered-dither">-ordered-dither</a>, 982<a href="#radial-blur">-radial-blur</a>, 983<a href="#random-threshold">-random-threshold</a>, 984<a href="#separate">-separate</a>, 985<a href="#threshold">-threshold</a>, and 986<a href="#white-threshold">-white-threshold</a>. 987</p> 988 989<p>Warning, some operators behave differently when the <a href="#channel" 990>+channel</a> default setting is in effect, verses ANY user defined <a 991href="#channel" >-channel</a> setting (including the equivalent of the 992default). These operators have yet to be made to understand the newer 'Sync' 993flag. </p> 994 995<p>For example <a href="#threshold">-threshold</a> will by default gray-scale 996the image before thresholding, if no <a href="#channel" >-channel</a> setting 997has been defined. This is not 'Sync flag controlled, yet. </p> 998 999<p>Also some operators such as <a href="#blur">-blur</a>, <a 1000href="#gaussian-blur">-gaussian-blur</a>, will modify their handling of the 1001color channels if the '<kbd>alpha</kbd>' channel is also enabled by <a 1002href="#channel" >-channel</a>. Generally this done to ensure that 1003fully-transparent colors are treated as being fully-transparent, and thus any 1004underlying 'hidden' color has no effect on the final results. Typically 1005resulting in 'halo' effects. The newer <a href="#morphology">-morphology</a> 1006convolution equivalents however does have a understanding of the 'Sync' flag 1007and will thus handle transparency correctly by default. </p> 1008 1009<p>As a alpha channel is optional within images, some operators will read the 1010color channels of an image as a greyscale alpha mask, when the image has no 1011alpha channel present, and the <a href="#channel" >-channel</a> setting tells 1012the operator to apply the operation using alpha channels. The <a 1013href="#clut">-clut</a> operator is a good example of this. </p> 1014 1015 1016<div style="margin: auto;"> 1017 <h4><a id="clamp"></a>-clamp</h4> 1018</div> 1019 1020<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Restrict image colors from 0 to the quantum depth.</td><td style='text-align:right;'></td></tr></table> 1021 1022<div style="margin: auto;"> 1023 <h4><a id="charcoal"></a>-charcoal <em class="arg">factor</em></h4> 1024</div> 1025 1026<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Simulate a charcoal drawing.</td><td style='text-align:right;'></td></tr></table> 1027 1028<div style="margin: auto;"> 1029 <h4><a id="chop"></a>-chop <em class="arg">geometry</em></h4> 1030</div> 1031 1032<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Remove pixels from the interior of an image.</td><td style='text-align:right;'></td></tr></table> 1033 1034<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. The <em class="arg">width</em> 1035and <em class="arg">height</em> given in the of the <em class="arg">size</em> 1036portion of the <em class="arg">geometry</em> argument give the number of 1037columns and rows to remove. The <em class="arg">offset</em> portion of 1038the <em class="arg">geometry</em> argument is influenced by 1039a <a href="#gravity">-gravity</a> setting, if present.</p> 1040 1041<p>The <a href="#chop">-chop</a> option removes entire rows and columns, 1042and moves the remaining corner blocks leftward and upward to close the gaps.</p> 1043 1044<p>While it can remove internal rows and columns of pixels, it is more typically 1045used with as <a href="#gravity">-gravity</a> setting and a '<kbd>+0+0</kbd>' offset 1046so as to remove a single edge from an image. Compare this to <a href="#shave" 1047>-shave</a> whcih removes equal numbers of pixels from oppisite sides of the image. 1048</p> 1049 1050<p>Using <a href="#chop">-chop</a> will effectivally undo the results of a 1051<a href="#splice">-splice</a> that was given the same <em class="arg">geometry</em> 1052and <a href="#gravity">-gravity</a> settings. </p> 1053 1054 1055<div style="margin: auto;"> 1056 <h4><a id="clip"></a>-clip</h4> 1057</div> 1058 1059<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Apply the clipping path if one is present.</td><td style='text-align:right;'></td></tr></table> 1060 1061<p>If a clipping path is present, it is applied to subsequent operations.</p> 1062 1063<p>For example, in the command</p> 1064 1065<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -clip -negate cockatoo.tif negated.tif</span></p> 1066<p>only the pixels within the clipping path are negated.</p> 1067 1068<p>The <a href="#clip">-clip</a> feature requires the XML library. If the XML library is not present, the option is ignored.</p> 1069 1070<div style="margin: auto;"> 1071 <h4><a id="clip-mask"></a>-clip-mask</h4> 1072</div> 1073 1074<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Clip the image as defined by this mask.</td><td style='text-align:right;'></td></tr></table> 1075 1076<p>Use the given image as a 'do-not-modify' mask of the current images in the 1077current image sequence. Assuming the clipmask is a greyscale image the same 1078size at the one already in memory, any areas that is white will not be 1079modified by any of the 'image processing operators' that follow, until the 1080mask is removed. Pixels in the black areas of the clip mask will be modified 1081as normal. </p> 1082 1083<p>In some ways this is similar to (though not the same) as defining 1084a rectangular <a href="#region" >-region</a>, or using the negative of the 1085mask (thrid) image in a three image <a href="#composite" >-composite</a>, 1086operation. </p> 1087 1088 1089<div style="margin: auto;"> 1090 <h4><a id="clip-path"></a>-clip-path <em class="arg">id</em></h4> 1091</div> 1092 1093<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Clip along a named path from the 8BImageMagick profile.</td><td style='text-align:right;'></td></tr></table> 1094 1095<p>This is almost identical to <a href="#clip">-clip</a>. </p> 1096 1097 1098<div style="margin: auto;"> 1099 <h4><a id="clone"></a>-clone <em class="arg">index(s)</em></h4> 1100</div> 1101 1102<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>make a clone of an image (or images).</td><td style='text-align:right;'></td></tr></table> 1103 1104<p>Inside parenthesis (where the operator is normally used) it will make a 1105clone of the images from the last 'pushed' image sequence, and adds them to 1106the end of the current image sequence. Outside parenthesis 1107(not recommended) it clones the images from the current image sequence. </p> 1108 1109<p>Specify the image by its index in the sequence. The first image is index 11100. Negative indexes are relative to the end of the sequence; for 1111example, <kbd>−1</kbd> 1112represents the last image of the sequence. Specify a range of images with a 1113dash (e.g. <kbd>0−4</kbd>). Separate multiple indexes with commas but no 1114spaces (e.g. <kbd>0,2,5</kbd>). A value of '<kbd>0−−1</kbd> will 1115effectively clone all the images. </p> 1116 1117<p>The <a href="#clone">+clone</a> will simply make a copy of the last image 1118in the image sequence, and is thus equivelent to using a argument of 1119'<kbd>−1</kbd>'. </p> 1120 1121<div style="margin: auto;"> 1122 <h4><a id="clut"></a>-clut</h4> 1123</div> 1124 1125<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Replace the channel values in the first image using each 1126corresponding channel in the second image as a <b>c</b>olor 1127<b>l</b>ook<b>u</b>p <b>t</b>able.</td><td style='text-align:right;'></td></tr></table> 1128 1129<p>The second (LUT) image is ordinarily a gradient image containing the 1130histogram mapping of how each channel should be modified. Typically it is a 1131either a single row or column image of replacement color values. If larger 1132than a single row or column, values are taken from a diagonal line from 1133top-left to bottom-right corners.</p> 1134 1135<p>The lookup is further controlled by the <a 1136href="#interpolate">-interpolate</a> setting, which is especially handy for an 1137LUT which is not the full length needed by the ImageMagick installed Quality 1138(Q) level. Good settings for this are the '<kbd>bilinear</kbd>' and 1139'<kbd>bicubic</kbd>' interpolation settings, which give smooth color 1140gradients, and the '<kbd>integer</kbd>' setting for a direct, unsmoothed 1141lookup of color values. </p> 1142 1143<p>This operator is especially suited to replacing a grayscale image with a 1144specific color gradient from the CLUT image. </p> 1145 1146<p>Only the channel values defined by the <a href="#channel">-channel</a> 1147setting will have their values replaced. In particular, since the default <a 1148href="#channel">-channel</a> setting is <kbd>RGB</kbd>, this means that 1149transparency (alpha/matte channel) is not affected, unless the <a 1150href="#channel">-channel</a> setting is modified. When the alpha channel is 1151set, it is treated by the <a href="#clut" >-clut</a> operator in the same way 1152as the other channels, implying that alpha/matte values are replaced using the 1153alpha/matte values of the original image. </p> 1154 1155<p>If either the image being modified, or the lookup image, contains no 1156transparency (i.e. <a href="#alpha" >-alpha</a> is turned 'off') but the <a 1157href="#channel">-channel</a> setting includes alpha replacement, then it is 1158assumed that image represents a gray-scale gradient which is used for the 1159replacement alpha values. That is you can use a gray-scale CLUT image to 1160adjust a existing images alpha channel, or you can color a gray-scale image 1161using colors form CLUT containing the desired colors, including transparency. 1162</p> 1163 1164<p>See also <a href="#hald-clut" >-hald-clut</a> which replaces colors 1165according to the lookup of the full color RGB value from a 2D representation 1166of a 3D color cube. </p> 1167 1168 1169<div style="margin: auto;"> 1170 <h4><a id="coalesce"></a>-coalesce</h4> 1171</div> 1172 1173<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Fully define the look of each frame of an GIF animation sequence, to form a 'film strip' animation.</td><td style='text-align:right;'></td></tr></table> 1174 1175<p>Overlay each image in an image sequence according to 1176its <a href="#dispose">-dispose</a> meta-data, to reproduce the look of 1177an animation at each point in the animation sequence. All images should be 1178the same size, and are assigned appropriate GIF disposal settings for the 1179animation to continue working as expected as a GIF animation. Such frames 1180are more easily viewed and processed than the highly optimized GIF overlay 1181images. </p> 1182 1183<p>The animation can be re-optimized after processing using 1184the <a href="#layers">-layers</a> method '<kbd>optimize</kbd>', although 1185there is no guarantee that the restored GIF animation optimization is 1186better than the original. </p> 1187 1188 1189<div style="margin: auto;"> 1190 <h4><a id="colorize"></a>-colorize <em class="arg">value</em></h4> 1191</div> 1192 1193<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Colorize the image by an amount specified by <em class="arg">value</em> using the color specified by the most recent <a href="#fill" >-fill</a> setting.</td><td style='text-align:right;'></td></tr></table> 1194 1195<p>Specify the amount of colorization as a percentage. Separate colorization 1196values can be applied to the red, green, and blue channels of the image with 1197a comma-delimited list of colorization 1198values (e.g., <kbd>-colorize 0,0,50</kbd>).</p> 1199 1200<div style="margin: auto;"> 1201 <h4><a id="colormap"></a>-colormap <em class="arg">type</em></h4> 1202</div> 1203 1204<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Define the colormap type.</td><td style='text-align:right;'>[<a href="/www/animate.html">animate</a>, <a href="/www/display.html">display</a>]</td></tr></table> 1205 1206<p>The <em class="arg">type</em> can be <kbd>shared</kbd> or <kbd>private</kbd>.</p> 1207 1208<p>This option only applies when the default X server visual 1209is <kbd>PseudoColor</kbd> or <kbd>GrayScale</kbd>. Refer 1210to <a href="#visual">-visual</a> for more details. By default, 1211a shared colormap is allocated. The image shares colors with 1212other X clients. Some image colors could be approximated, 1213therefore your image may look very different than intended. 1214If <kbd>private</kbd> is chosen, the image colors appear exactly 1215as they are defined. However, other clients may go <em>technicolor</em> 1216when the image colormap is installed.</p> 1217 1218<div style="margin: auto;"> 1219 <h4><a id="colors"></a>-colors <em class="arg">value</em></h4> 1220</div> 1221 1222<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the preferred number of colors in the image.</td><td style='text-align:right;'></td></tr></table> 1223 1224<p>The actual number of colors in the image may be less than your request, 1225but never more. Note that this a color reduction option. Images with fewer 1226unique colors than specified by <em class="arg">value</em> will have any 1227duplicate or unused colors removed. The ordering of an existing color 1228palette may be altered. When converting an image from color to grayscale, 1229it is more efficient to convert the image to the gray colorspace before 1230reducing the number of colors. Refer to 1231the <a href="/www/quantize.html"> 1232color reduction algorithm</a> for more details.</p> 1233 1234<div style="margin: auto;"> 1235 <h4><a id="color-matrix"></a>-color-matrix <em class="arg">matrix</em></h4> 1236</div> 1237 1238<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>apply color correction to the image.</td><td style='text-align:right;'></td></tr></table> 1239 1240<p>This option permits saturation changes, hue rotation, luminance to alpha, 1241and various other effects. Although variable-sized transformation matrices 1242can be used, typically one uses a 5x5 matrix for an RGBA image and a 6x6 1243for CMYKA (or RGBA with offsets). The matrix is similar to those used by 1244Adobe Flash except offsets are in column 6 rather than 5 (in support of 1245CMYKA images) and offsets are normalized (divide Flash offset by 255).</p> 1246 1247<p>As an example, to add contrast to an image with offsets, try this command:</p> 1248 1249<pre class="text"> 1250convert kittens.jpg -color-matrix \ 1251 " 1.5 0.0 0.0 0.0, 0.0, -0.157 \ 1252 0.0 1.5 0.0 0.0, 0.0, -0.157 \ 1253 0.0 0.0 1.5 0.0, 0.0, -0.157 \ 1254 0.0 0.0 0.0 1.0, 0.0, 0.0 \ 1255 0.0 0.0 0.0 0.0, 1.0, 0.0 \ 1256 0.0 0.0 0.0 0.0, 0.0, 1.0" kittens.png 1257</pre> 1258<div style="margin: auto;"> 1259 <h4><a id="colorspace"></a>-colorspace <em class="arg">value</em></h4> 1260</div> 1261 1262<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the image colorspace.</td><td style='text-align:right;'></td></tr></table> 1263 1264<p>Choices are:</p> 1265 1266<pre class="text"> 1267 CMY 1268 CMYK 1269 Gray 1270 HSB 1271 HSL 1272 HWB 1273 Lab 1274 Log 1275 OHTA 1276 Rec601Luma 1277 Rec601YCbCr 1278 Rec709Luma 1279 Rec709YCbCr 1280 RGB 1281 sRGB 1282 Transparent 1283 XYZ 1284 YCbCr 1285 YCC 1286 YIQ 1287 YPbPr 1288 YUV 1289</pre> 1290 1291<p>To print a complete list of colorspaces, use <a href="#list">-list colorspace</a>.</p> 1292 1293<p>For a more accurate color conversion to or from the RGB, CMYK, or grayscale colorspaces, use the <a href="#profile">-profile</a> option.</p> 1294 1295<table class="doc"> 1296 <caption>Conversion Of RGB To Other Color Spaces</caption> 1297 <tr><th align="left" valign="middle">CMY</th></tr> 1298 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>−R</td></tr> 1299 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>−G</td></tr> 1300 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>−B</td></tr> 1301 <tr><th align="left" valign="middle">CMYK — starts with CMY from above</th></tr> 1302 <tr><td align="left" valign="middle">K=min(C,Y,M)</td></tr> 1303 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>*(C−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 1304 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>*(M−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 1305 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>*(Y−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 1306 1307 <tr><th align="left" valign="middle">Gray</th></tr> 1308 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr> 1309 1310 <tr><th align="left" valign="middle">HSB — Hue, Saturation, Brightness; like a cone peak downward</th></tr> 1311 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr> 1312 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr> 1313 <tr><td align="left" valign="middle">B=distance along axis from bottom upward; B=max(R,G,B); <em>intensity-like</em></td></tr> 1314 1315 <tr><th align="left" valign="middle">HSL — Hue, Saturation, Lightness; like a double cone end-to-end with peaks at very top and bottom</th></tr> 1316 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr> 1317 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr> 1318 <tr><td align="left" valign="middle">L=distance along axis from bottom upward; L=0.5*max(R,G,B) + 0.5*min(R,G,B); <em>intensity-like</em></td></tr> 1319 1320 <tr><th align="left" valign="middle">HWB — Hue, Whiteness, Blackness</th></tr> 1321 <tr><td align="left" valign="middle">Hue (complicated equation)</td></tr> 1322 <tr><td align="left" valign="middle">Whiteness (complicated equation)</td></tr> 1323 <tr><td align="left" valign="middle">Blackness (complicated equation)</td></tr> 1324 1325 <tr><th align="left" valign="middle">LAB</th></tr> 1326 <tr><td align="left" valign="middle">L (complicated equation relating X,Y,Z)</td></tr> 1327 <tr><td align="left" valign="middle">A (complicated equation relating X,Y,Z)</td></tr> 1328 <tr><td align="left" valign="middle">B (complicated equation relating X,Y,Z)</td></tr> 1329 1330 <tr><th align="left" valign="middle">LOG</th></tr> 1331 <tr><td align="left" valign="middle">I1 (complicated equation involving logarithm of R)</td></tr> 1332 <tr><td align="left" valign="middle">I2 (complicated equation involving logarithm of G)</td></tr> 1333 <tr><td align="left" valign="middle">I3 (complicated equation involving logarithm of B)</td></tr> 1334 1335 <tr><th align="left" valign="middle">OHTA — approximates principal components transformation</th></tr> 1336 <tr><td align="left" valign="middle">I1=0.33333*R+0.33334*G+0.33333*B; <em>intensity-like</em></td></tr> 1337 <tr><td align="left" valign="middle">I2=(0.50000*R+0.00000*G−0.50000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1338 <tr><td align="left" valign="middle">I3=(−0.25000*R+0.50000*G−0.25000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1339 1340 <tr><th align="left" valign="middle">Rec601Luma</th></tr> 1341 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr> 1342 1343 <tr><th align="left" valign="middle">Rec601YCbCr</th></tr> 1344 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1345 <tr><td align="left" valign="middle">Cb=(−0.168736*R-0.331264*G+0.500000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1346 <tr><td align="left" valign="middle">Cr=(0.500000*R−0.418688*G−0.081312*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1347 1348 <tr><th align="left" valign="middle">Rec709Luma</th></tr> 1349 <tr><td align="left" valign="middle">Gray=0.21260*R+0.71520*G+0.07220*B</td></tr> 1350 1351 <tr><th align="left" valign="middle">Rec709YCbCr</th></tr> 1352 <tr><td align="left" valign="middle">Y=0.212600*R+0.715200*G+0.072200*B; <em>intensity-like</em></td></tr> 1353 <tr><td align="left" valign="middle">Cb=(−0.114572*R−0.385428*G+0.500000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1354 <tr><td align="left" valign="middle">Cr=(0.500000*R−0.454153*G−0.045847*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1355 1356 <tr><th align="left" valign="middle">sRGB</th></tr> 1357 <tr><td align="left" valign="middle">if Rs ≤ .03928 then Rs=R/12.92 else Rs=((R+.055)/1.055)^2.4</td></tr> 1358 <tr><td align="left" valign="middle">if Gs ≤ .03928 then Gs=B/12.92 else Gs=((G+.055)/1.055)^2.4</td></tr> 1359 <tr><td align="left" valign="middle">if Bs ≤ .03928 then Bs=B/12.92 else Bs=((B+.055)/1.055)^2.4</td></tr> 1360 1361 <tr><th align="left" valign="middle">XYZ</th></tr> 1362 <tr><td align="left" valign="middle">X=0.4124240*R+0.3575790*G+0.1804640*B</td></tr> 1363 <tr><td align="left" valign="middle">Y=0.2126560*R+0.7151580*G+0.0721856*B</td></tr> 1364 <tr><td align="left" valign="middle">Z=0.0193324*R+0.1191930*G+0.9504440*B</td></tr> 1365 1366 <tr><th align="left" valign="middle">YCC</th></tr> 1367 <tr><td align="left" valign="middle">Y=(0.29900*R+0.58700*G+0.11400*B) (with complicated scaling); <em>intensity-like</em></td></tr> 1368 <tr><td align="left" valign="middle">C1=(−0.29900*R−0.58700*G+0.88600*B) (with complicated scaling)</td></tr> 1369 <tr><td align="left" valign="middle">C2=(0.70100*R−0.58700*G−0.11400*B) (with complicated scaling)</td></tr> 1370 1371 <tr><th align="left" valign="middle">YCbCr</th></tr> 1372 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1373 <tr><td align="left" valign="middle">Cb=(−0.168736*R−0.331264*G+0.500000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1374 <tr><td align="left" valign="middle">Cr=(0.500000*R−0.418688*G−0.081312*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1375 1376 <tr><th align="left" valign="middle">YIQ</th></tr> 1377 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr> 1378 <tr><td align="left" valign="middle">I=(0.59600*R−0.27400*G−0.32200*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1379 <tr><td align="left" valign="middle">Q=(0.21100*R−0.52300*G+0.31200*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1380 1381 <tr><th align="left" valign="middle">YPbPr</th></tr> 1382 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1383 <tr><td align="left" valign="middle">Pb=(−0.168736*R−0.331264*G+0.500000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1384 <tr><td align="left" valign="middle">Pr=(0.500000*R−0.418688*G−0.081312*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1385 1386 <tr><th align="left" valign="middle">YUV</th></tr> 1387 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr> 1388 <tr><td align="left" valign="middle">U=(−0.14740*R−0.28950*G+0.43690*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1389 <tr><td align="left" valign="middle">V=(0.61500*R−0.51500*G−0.10000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1390</table> 1391 1392<div style="margin: auto;"> 1393 <h4><a id="combine"></a>-combine</h4> 1394</div> 1395 1396<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Combine one or more images into a single image.</td><td style='text-align:right;'></td></tr></table> 1397 1398<p>The channels (previously set by <a href="#channel">-channel</a>) of the combined image are taken from the grayscale values of each image in the sequence, in order. For the default -channel setting of <kbd>RGB</kbd>, this means the first image is assigned to the <kbd>Red</kbd> channel, the second to the <kbd>Green</kbd> channel, the third to the <kbd>Blue</kbd>.</p> 1399 1400<p>This option can be thought of as the inverse to <a href="#separate">-separate</a>, so long as the channel settings are the same. Thus, in the following example, the final image should be a copy of the original. 1401</p> 1402 1403<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert original.png -channel RGB -separate sepimage.png</span><span class='crtout'></span><span class="crtprompt"> $magick> </span><span class='crtin'>convert sepimage-0.png sepimage-1.png sepimage-2.png -channel RGB \ <br/> -combine imagecopy.png</span></p> 1404<div style="margin: auto;"> 1405 <h4><a id="comment"></a>-comment <em class="arg">string</em></h4> 1406</div> 1407 1408<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Embed a comment in an image.</td><td style='text-align:right;'></td></tr></table> 1409 1410<p>This option sets the comment meta-data of an image read in after this 1411option has been given. To modify a comment of images already in memory use 1412"<kbd><a href="#set">-set</a> comment</kbd>". </p> 1413 1414<p>The comment can contain special format characters listed in the <a 1415href="/www/escape.html">Format and 1416Print Image Properties</a>. These attributes are expanded when the comment 1417is finally assigned to the individual images. </p> 1418 1419<p>If the first character of <em class="arg">string</em> is <em 1420class="arg">@</em>, the image comment is read from a file titled by the 1421remaining characters in the string. Comments read in from a file are literal; 1422no embedded formatting characters are recognized.</p> 1423 1424<p>Comment meta-data are not visible on the image itself. To do that use the 1425<a href="#annotate">-annotate</a> or <a href="#draw">-draw</a> options 1426instead.</p> 1427 1428<p>For example,</p> 1429 1430<p class="crtsnip"> 1431 -comment "%m:%f %wx%h" bird.miff 1432</p> 1433 1434<p>produces an image comment of <kbd>MIFF:bird.miff 512x480</kbd> (assuming 1435that the image <kbd>bird.miff</kbd> has a width of 512 and a height of 1436480.</p> 1437 1438<div style="margin: auto;"> 1439 <h4><a id="compose"></a>-compose <em class="arg">operator</em></h4> 1440</div> 1441 1442<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the type of image composition.</td><td style='text-align:right;'></td></tr></table> 1443 1444<p>See <a href="/www/compose.html">Alpha Compositing</a> for 1445a detailed discussion of alpha compositing.</p> 1446 1447<p>This setting effects image processing operators that merge two (or more) 1448images together in some way. This includes the operators, 1449<a href="#composite">-composite</a>, 1450<a href="#layers">-layers</a> composite, 1451<a href="#flatten">-flatten</a>, 1452<a href="#mosaic">-mosaic</a>, 1453<a href="#layers">-layers</a> merge, 1454<a href="#border">-border</a>, 1455<a href="#frame">-frame</a>, 1456and <a href="#extent">-extent</a>. </p> 1457 1458<p>It is also one of the primary options for the "<kbd>composite</kbd>" 1459command. </p> 1460 1461 1462<div style="margin: auto;"> 1463 <h4><a id="composite"></a>-composite</h4> 1464</div> 1465 1466<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Perform alpha composition on two images and an optional mask</td><td style='text-align:right;'></td></tr></table> 1467 1468<p>Take the first image 'destination' and overlay the second 'source' image 1469according to the current <a href="#compose">-compose</a> setting. The location 1470of the 'source' or 'overlay' image is controlled according to <a 1471href="#geometry" >-geometry</a>, and <a href="#geometry" >-geometry</a> 1472settings. </p> 1473 1474<p>If a third image is given this is treated as a gray-scale 'mask' image 1475relative to the first 'destination' image. This mask will limit what parts of 1476the destination can be modified by the image composition. However for the 1477'<kbd>displace</kbd>' compose method, the mask is used to provide a separate 1478Y-displacement image instead. </p> 1479 1480<p>If a <a href="#compose">-compose</a> method requires extra numerical 1481arguments or flags these can be provided by setting the <a 1482href="#set">-set</a> '<kbd class="arg">option:compose:args</kbd>' 1483appropriately for the compose method. </p> 1484 1485<p>Some <a href="#compose">-compose</a> methods can modify the 'destination' 1486image outside the overlay area. You can disable this by setting the special <a 1487href="#set">-set</a> '<kbd class="arg">option:compose:outside-overlay</kbd>' 1488to '<kbd>false</kbd>'. </p> 1489 1490 1491<div style="margin: auto;"> 1492 <h4><a id="compress"></a>-compress <em class="arg">type</em></h4> 1493</div> 1494 1495<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Use pixel compression specified by <em class="arg">type</em> when writing the image.</td><td style='text-align:right;'></td></tr></table> 1496 1497<p>Choices are: <kbd class="arg">None</kbd>, <kbd class="arg">BZip</kbd>, <kbd class="arg">Fax</kbd>, <kbd class="arg">Group4</kbd>, <kbd class="arg">JPEG</kbd>, <kbd class="arg">JPEG2000</kbd>, <kbd class="arg">Lossless</kbd>, <kbd class="arg">LZW</kbd>, <kbd class="arg">RLE</kbd> or <kbd class="arg">Zip</kbd>.</p> 1498 1499<p>To print a complete list of compression types, use <a href="#list">-list compress</a>.</p> 1500 1501<p>Specify <a href="#compress">+compress</a> to store the binary image in an uncompressed format. The default is the compression type of the specified image file.</p> 1502 1503<p>If <kbd>LZW</kbd> compression is specified but LZW compression has not been enabled, the image data is written in an uncompressed LZW format that can be read by LZW decoders. This may result in larger-than-expected GIF files.</p> 1504 1505<p><kbd>Lossless</kbd> refers to lossless JPEG, which is only available if the JPEG library has been patched to support it. Use of lossless JPEG is generally not recommended.</p> 1506 1507<p>Use the <a href="#quality">-quality</a> option to set the compression level to be used by JPEG, PNG, MIFF, and MPEG encoders. Use the <a href="#sampling-factor">-sampling-factor</a> option to set the sampling factor to be used by JPEG, MPEG, and YUV encoders for down-sampling the chroma channels.</p> 1508 1509<div style="margin: auto;"> 1510 <h4><a id="contrast"></a>-contrast</h4> 1511</div> 1512 1513<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Enhance or reduce the image contrast.</td><td style='text-align:right;'></td></tr></table> 1514 1515<p>This option enhances the intensity differences between the lighter and darker elements of the image. Use <a href="#contrast">-contrast</a> to enhance the image or <a href="#contrast">+contrast</a> to reduce the image contrast.</p> 1516 1517<p>For a more pronounced effect you can repeat the option:</p> 1518 1519<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -contrast -contrast rose_c2.png</span></p> 1520<div style="margin: auto;"> 1521 <h4><a id="contrast-stretch"></a>-contrast-stretch <em class="arg">black-point</em><br />-contrast-stretch <em class="arg">black-point</em>{x<em class="arg">white-point</em>}{<em class="arg">%</em>}}</h4> 1522</div> 1523 1524<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Increase the contrast in an image by <em>stretching</em> the range of intensity values.</td><td style='text-align:right;'></td></tr></table> 1525 1526<p>While performing the stretch, black-out at most <em 1527class="arg" >black-point</em> pixels and white-out at most <em 1528class="arg" >white-point</em> pixels. Or, if percent is used, black-out at most 1529<em class="arg" >black-point %</em> pixels and white-out at most <em 1530class="arg" >white-point %</em> pixels.</p> 1531 1532<p>Prior to ImageMagick 6.4.7-0, <a href="#contrast-stretch" 1533>-contrast-stretch</a> will black-out at most <em class="arg" 1534>black-point</em> pixels and white-out at most <em class="arg" >total pixels 1535minus white-point</em> pixels. Or, if percent is used, black-out at most <em 1536class="arg">black-point %</em> pixels and white-out at most <em class="arg" 1537>100% minus white-point %</em> pixels.</p> 1538 1539<p>Note that <kbd>-contrast-stretch 0</kbd> will modify the image such that 1540the image's min and max values are stretched to 0 and <em class="QR" 1541>QuantumRange</em>, respectively, without any loss of data due to burn-out or 1542clipping at either end. This is not the same as <a href="#normalize" 1543>-normalize</a>, which is equivalent to <kbd>-contrast-stretch 0.15x0.05%</kbd> (or 1544prior to ImageMagick 6.4.7-0, <kbd>-contrast-stretch 2%x99%</kbd>).</p> 1545 1546<p>Internally operator works by creating a histogram bin, and then uses that 1547bin to modify the image. As such some colors may be merged together when they 1548originally fell into the same 'bin'. </p> 1549 1550<p>All the channels are normalized in concert by the came amount so as to 1551preserve color integrity, when the default <a href="#channel" >+channel</a> 1552setting is in use. Specifying any other <a href="#channel" >-channel</a> 1553setting will normalize the RGB channels independently.</p> 1554 1555<p>See also <a href="#auto-level" >-auto-level</a> for a 'perfect' 1556normalization of mathematical images. </p> 1557 1558<p>This operator is under review for re-development. </p> 1559 1560 1561<div style="margin: auto;"> 1562 <h4><a id="convolve"></a>-convolve <em class="arg">kernel</em></h4> 1563</div> 1564 1565<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Convolve an image with a user-supplied convolution kernel.</td><td style='text-align:right;'></td></tr></table> 1566 1567<p>The <em class="arg">kernel</em> is a matrix specified as 1568a comma-separated list of integers (with no spaces), ordered left-to right, 1569starting with the top row. Presently, only odd-dimensioned kernels are 1570supported, and therefore the number of entries in the specified <em 1571class="arg">kernel</em> must be 3<sup>2</sup>=9, 5<sup>2</sup>=25, 15727<sup>2</sup>=49, etc. </p> 1573 1574<p>Note that the <a href="/www/command-line-options.html#convolve">‑convolve</a> operator supports the <a href="/www/command-line-options.html#bias">‑bias</a> setting. This option shifts the convolution so that 1575positive and negative results are relative to a user-specified bias value. 1576This is important for non-HDRI compilations of ImageMagick when dealing with 1577convolutions that contain negative as well as positive values. This is 1578especially the case with convolutions involving high pass filters or edge 1579detection. Without an output bias, the negative values is clipped at zero. 1580</p> 1581 1582<p>When using an ImageMagick with the HDRI compile-time setting, <a href="/www/command-line-options.html#bias">‑bias</a> is not needed, as ImageMagick is able to store/handle any 1583negative results without clipping to the color value range (0..QuantumRange). 1584See the discussion on HDRI implementations of ImageMagick on the page <a 1585href="/www/high-dynamic-range.html">High 1586Dynamic-Range Images</a>. For more about HDRI go the ImageMagick <a 1587href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this 1588<a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a> 1589entry. </p> 1590 1591 1592<div style="margin: auto;"> 1593 <h4><a id="crop"></a>-crop <em class="arg">geometry</em></h4> 1594</div> 1595 1596<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Cut out one or more rectangular regions of the image.</td><td style='text-align:right;'></td></tr></table> 1597 1598<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 1599 1600<p>The <em class="arg">width</em> and <em class="arg">height</em> of the <em class="arg">geometry</em> argument give the size of the image that remains after cropping, and <em class="arg">x</em> and <em class="arg">y</em> in the <em class="arg">offset</em> (if present) gives the location of the top left corner of the cropped image with respect to the original image. To specify the amount to be removed, use <a href="#shave">-shave</a> instead.</p> 1601 1602<p>If the <em class="arg">x</em> and <em class="arg">y</em> offsets are present, a single image is generated, consisting of the pixels from the cropping region. The offsets specify the location of the upper left corner of the cropping region measured downward and rightward with respect to the upper left corner of the image. If the <a href="#gravity">-gravity</a> option is present with <kbd>NorthEast</kbd>, <kbd>East</kbd>, or <kbd>SouthEast</kbd> gravity, it gives the distance leftward from the right edge of the image to the right edge of the cropping region. Similarly, if the <a href="#gravity">-gravity</a> option is present with <kbd>SouthWest</kbd>, <kbd>South</kbd>, or <kbd>SouthEast</kbd> gravity, the distance is measured upward between the bottom edges.</p> 1603 1604<p>If the <em class="arg">x</em> and <em class="arg">y</em> offsets are omitted, a set of tiles of the specified geometry, covering the entire input image, is generated. The rightmost tiles and the bottom tiles are smaller if the specified geometry extends beyond the dimensions of the input image.</p> 1605 1606<p>By adding a exclamation character flag to the geometry argument, the 1607cropped images virtual canvas page size and offset is set as if the 1608geometry argument was a viewport or window. This means the canvas page size 1609is set to exactly the same size you specified, the image offset set 1610relative top left corner of the region cropped. </p> 1611 1612<p>If the cropped image 'missed' the actual image on its virtual canvas, a 1613special single pixel transparent 'missed' image is returned, and a 'crop 1614missed' warning given. </p> 1615 1616<p>It might be necessary to <a href="#repage" >+repage</a> the image prior to cropping the image to ensure the crop coordinate frame is relocated to the upper-left corner of the visible image.</p> 1617 1618<div style="margin: auto;"> 1619 <h4><a id="cycle"></a>-cycle <em class="arg">amount</em></h4> 1620</div> 1621 1622<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>displace image colormap by amount.</td><td style='text-align:right;'></td></tr></table> 1623 1624<p><em class="arg">Amount</em> defines the number of positions each 1625colormap entry is shifted.</p> 1626 1627 1628<div style="margin: auto;"> 1629 <h4><a id="debug"></a>-debug <em class="arg">events</em></h4> 1630</div> 1631 1632<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>enable debug printout.</td><td style='text-align:right;'></td></tr></table> 1633 1634<p>The <kbd>events</kbd> parameter specifies which events are to be logged. It can be either <kbd>None</kbd>, <kbd>All</kbd>, <kbd>Trace</kbd>, or a comma-separated list consisting of one or more of the following domains: <kbd>Annotate</kbd>, <kbd>Blob</kbd>, <kbd>Cache</kbd>, <kbd>Coder</kbd>, <kbd>Configure</kbd>, <kbd>Deprecate</kbd>, <kbd>Exception</kbd>, <kbd>Locale</kbd>, <kbd>Render</kbd>, <kbd>Resource</kbd>, <kbd>Security</kbd>, <kbd>TemporaryFile</kbd>, <kbd>Transform</kbd>, <kbd>X11</kbd>, or <kbd>User</kbd>. </p> 1635 1636 1637<p>For example, to log cache and blob events, use.</p> 1638 1639<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -debug "Cache,Blob" rose: rose.png</span></p> 1640<p>The <kbd>User</kbd> domain is normally empty, but developers can log user events in their private copy of ImageMagick.</p> 1641 1642<p>To print the complete list of debug methods, use <a href="#list">-list debug</a>.</p> 1643 1644<p>Use the <a href="#log">-log</a> option to specify the format for debugging output.</p> 1645 1646<p>Use <a href="#debug">+debug</a> to turn off all logging.</p> 1647 1648<p>Debugging may also be set using the <kbd>MAGICK_DEBUG</kbd> <a href="/www/resources.html#environment">environment variable</a>. The allowed values for the <kbd>MAGICK_DEBUG</kbd> environment variable are the same as for the <a href="#debug">-debug</a> option.</p> 1649 1650 1651<div style="margin: auto;"> 1652 <h4><a id="decipher"></a>-decipher <em class="arg">filename</em></h4> 1653</div> 1654 1655<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Decipher and restore pixels that were previously transformed by <a href="#encipher">-encipher</a>.</td><td style='text-align:right;'></td></tr></table> 1656 1657<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p> 1658 1659<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p> 1660 1661 1662<div style="margin: auto;"> 1663 <h4><a id="deconstruct"></a>-deconstruct</h4> 1664</div> 1665 1666<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>find areas that has changed between images </td><td style='text-align:right;'></td></tr></table> 1667 1668<p>Given a sequence of images all the same size, such as produced by <a href="#coalesce">-coalesce</a>, replace the second and later images, with a smaller image of just the area that changed relative to the previous image. </p> 1669 1670<p>The resulting sequence of images can be used to optimize an animation sequence, though will not work correctly for GIF animations when parts of the animation can go from opaque to transparent. </p> 1671 1672<p>This option is actually equivalent to the <a href="#layers">-layers</a> method '<kbd>compare-any</kbd>'. </p> 1673 1674 1675<div style="margin: auto;"> 1676 <h4><a id="define"></a>-define <em class="arg">key</em>{<em class="arg">=value</em>}<em class="arg">...</em></h4> 1677</div> 1678 1679<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>add specific global settings generally used to control 1680coders and image processing operations.</td><td style='text-align:right;'></td></tr></table> 1681 1682<p>This option creates one or more definitions for coders and decoders to use 1683while reading and writing image data. Definitions are generally used to 1684control image file format coder modules, and image processing operations, 1685beyond what is provided by normal means. Defined settings are listed in <a 1686href="#verbose" >-verbose</a> information ("<kbd>info:</kbd>" output format) 1687as "Artifacts". </p> 1688 1689<p>If <em class="arg">value</em> is missing for a definition, an empty-valued 1690definition of a flag is created with that name. This used to control on/off 1691options. Use <a href="#define">+define key</a> to remove definitions 1692previously created. Use <a href="#define">+define "*"</a> to remove all 1693existing definitions.</p> 1694 1695<p>The same 'artifact' settings can also be defined using the <a 1696href="#set" >-set "option:<em class="arg">key</em>" "<em class="arg" 1697>value</em>"</a> option, which also allows the use of <a href="/www/escape.html" >Format and Print Image 1698Properties</a> in the defined value. </p> 1699 1700<p>The <em>option</em> and <em>key</em> are case-independent (they are 1701converted to lowercase for use within the decoders) while the <em>value</em> 1702is case-dependent.</p> 1703 1704<p>Such settings are global in scope, and effect all images and operations. </p> 1705 1706<p>The following definitions are just some of the artifacts that are 1707available:</p> 1708 1709<dl> 1710<dt>dcm:display-range=reset</dt> 1711<dd>Set the display range to the minimum and maximum pixel values for the 1712 DCM image format.</dd> 1713 1714<dt>dot:layout-engine=<em class="arg">value</em></dt> 1715<dd>Set the specify the layout engine for the DOT image format (e.g. 1716 <kbd>neato</kbd>).</dd> 1717 1718<dt>jpeg:extent=<em class="arg">value</em></dt> 1719<dd>Restrict the maximum JPEG file size, for example <kbd>-define 1720 jpeg:extent=400kb</kbd>.</dd> 1721 1722<dt>jpeg:size=<em class="arg">geometry</em></dt> 1723<dd>Set the size hint of a JPEG image, for example, -define jpeg:size=128x128. 1724 It is most useful for increasing performance and reducing the memory 1725 requirements when reducing the size of a large JPEG image.</dd> 1726 1727<dt>jp2:rate=<em class="arg">value</em></dt> 1728<dd>Specify the compression factor to use while writing JPEG-2000 files. The 1729 compression factor is the reciprocal of the compression ratio. The valid 1730 range is 0.0 to 1.0, with 1.0 indicating lossless compression. If defined, 1731 this value overrides the -quality setting. A quality setting of 75 1732 results in a rate value of 0.06641.</dd> 1733 1734<dt>mng:need-cacheoff</dt> 1735 <dd>turn playback caching off for streaming MNG.</dd> 1736 1737<dt>png:bit-depth=<em class="arg">value</em></dt> 1738<dt>png:color-type=<em class="arg">value</em></dt> 1739<dd>desired bit-depth and color-type for PNG output. You can force the PNG 1740 encoder to use a different bit-depth and color-type than it would have 1741 normally selected, but only if this does not cause any loss of image 1742 quality. Any attempt to reduce image quality is treated as an error and no 1743 PNG file is written. E.g., if you have a 1-bit black-and-white image, you 1744 can use these "defines" to cause it to be written as an 8-bit grayscale, 1745 indexed, or even a 64-bit RGBA. But if you have a 16-million color image, 1746 you cannot force it to be written as a grayscale or indexed PNG. If you 1747 wish to do this, you must use the appropriate <a href="#depth">-depth</a>, 1748 <a href="#colors">-colors</a>, or <a href="#type">-type</a> directives to 1749 reduce the image quality prior to using the PNG encoder. Note that in 1750 indexed PNG files, "bit-depth" refers to the number of bits per index, 1751 which can be 1, 2, 4, or 8. In such files, the color samples always have 1752 8-bit depth.</dd> 1753 1754<dt>png:exclude-chunk=<em class="arg">value</em></dt> 1755<dt>png:include-chunk=<em class="arg">value</em></dt> 1756<dd>ancillary chunks to be excluded from or included in PNG output. 1757 1758 <p>The<em class="arg">value</em> can be the name of a PNG chunk-type such 1759 as <em class="arg">bKGD</em>, a comma-separated list of chunk-types, 1760 or the word <em class="arg">all</em> or 1761 the word <em class="arg">none</em>. There must be no spaces in the 1762 list. Although PNG chunk-names are case-dependent, you can use 1763 all lowercase names if you prefer.</p> 1764 1765 <p>The "include-chunk" and "exclude-chunk" lists only affect the behavior 1766 of the PNG encoder and have no effect on the PNG decoder.</p> 1767 1768 <p>As a special case, if the <kbd>sRGB</kbd> chunk is excluded and 1769 the <kbd>gAMA</kbd> chunk is included, the <kbd>gAMA</kbd> chunk will 1770 only be written if gamma is not 1/2.2, since most decoders assume 1771 sRGB and gamma=1/2.2 when no colorspace information is included in 1772 the PNG file. Because the list is processed from left to right, you 1773 can achieve this with a single define:</p> 1774 1775<pre class="text"> 1776 -define png:include-chunk=none,gAMA 1777</pre> 1778 1779 <p>The critical PNG chunks <kbd>IHDR</kbd>, <kbd>PLTE</kbd>, 1780 <kbd>IDAT</kbd>, and <kbd>IEND</kbd> cannot be excluded. Any of 1781 these entries appearing in the list will be ignored.</p> 1782 1783 <p>If the ancillary PNG <kbd>tRNS</kbd> chunk is excluded and the 1784 image has transparency, the PNG colortype is forced to be 4 or 6 1785 (GRAY_ALPHA or RGBA). If the image is not transparent, then the 1786 <kbd>tRNS</kbd> chunk isn't written anyhow, and there is no effect 1787 on the PNG colortype of the output image.</p> 1788 1789 <p>The <a href="#strip">-strip</a> option does the equivalent of the 1790 following for PNG output:</p> 1791 1792<pre class="text"> 1793 -define png:include-chunk=none,gama 1794</pre> 1795 1796 <p>The default behavior is to include all known PNG ancillary chunks 1797 plus ImageMagick's private <kbd>vpAg</kbd> ("virtual page") chunk, 1798 and to exclude all PNG chunks that are unknown to ImageMagick, 1799 regardless of their PNG "copy-safe" status as described in the 1800 PNG specification.</p> 1801 1802 <p>Any chunk names that are not known to ImageMagick are ignored 1803 if they appear in either the "include-chunk" or "exclude-chunk" list. 1804 The ancillary chunks currently known to ImageMagick are 1805 <kbd>bKGD</kbd>, <kbd>cHRM</kbd>, <kbd>gAMA</kbd>, <kbd>iCCP</kbd>, 1806 <kbd>oFFs</kbd>, <kbd>pHYs</kbd>, <kbd>sRGB</kbd>, <kbd>tEXt</kbd>, 1807 <kbd>tRNS</kbd>, <kbd>vpAg</kbd>, and <kbd>zTXt</kbd>.</p> 1808 1809y</dd> 1810 1811<dt>ps:imagemask</dt> 1812<dd>If the ps:imagemask flag is defined, the PS3 and EPS3 coders will create 1813 Postscript files that render bilevel images with the Postscript imagemask 1814 operator instead of the image operator.</dd> 1815 1816<dt>quantum:format=<em class="arg">type</em></dt> 1817<dd>Set the type to <kbd>floating-point</kbd> to specify a floating-point 1818 format for raw files (e.g. GRAY:) or for MIFF and TIFF images in HDRI mode 1819 to preserve negative values. If <a href="#depth">-depth</a> 16 is 1820 included, the result is a single precision floating point format. 1821 If <a href="#depth">-depth</a> 32 is included, the result is 1822 double precision floating point format.</dd> 1823 1824</dl> 1825 1826<p>For example, to create a postscript file that will render only the black 1827pixels of a bilevel image, use:</p> 1828 1829<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert bilevel.tif -define ps:imagemask eps3:stencil.ps</span></p> 1830<p>Set attributes of the image registry by prefixing the value with 1831<kbd>registry:</kbd>. For example, to set a temporary path to put work files, 1832use:</p> 1833 1834<p class="crtsnip"> 1835-define registry:temporary-path=/data/tmp 1836</p> 1837 1838 1839 1840<div style="margin: auto;"> 1841 <h4><a id="delay"></a>-delay <em class="arg">ticks</em> <br />-delay <em class="arg">ticks</em>x<em class="arg">ticks-per-second</em> {<em class="arg"><</em>} {<em class="arg">></em>}</h4> 1842</div> 1843 1844<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>display the next image after pausing.</td><td style='text-align:right;'></td></tr></table> 1845 1846<p>This option is useful for regulating the animation of image sequences <em>ticks/ticks-per-second</em> seconds must expire before the display of the next image. The default is no delay between each showing of the image sequence. The default ticks-per-second is 100.</p> 1847 1848<p>Use <kbd>></kbd> to change the image delay <em>only</em> if its current value exceeds the given delay. <kbd><</kbd> changes the image delay <em>only</em> if current value is less than the given delay. For example, if you specify <kbd>30></kbd> and the image delay is 20, the image delay does not change. However, if the image delay is 40 or 50, the delay it is changed to 30. Enclose the given delay in quotation marks to prevent the <kbd><</kbd> or <kbd>></kbd> from being interpreted by your shell as a file redirection.</p> 1849 1850 1851<div style="margin: auto;"> 1852 <h4><a id="delete"></a>-delete <em class="arg">indexes</em></h4> 1853</div> 1854 1855<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>delete the image, specified by its index, from the image sequence.</td><td style='text-align:right;'></td></tr></table> 1856 1857<p>Specify the image by its index in the sequence. The first image is index 0. Negative indexes are relative to the end of the sequence, for example, -1 represents the last image of the sequence. Specify a range of images with a dash (e.g. 0-4). Separate indexes with a comma (e.g. 0,2). Use <kbd>+delete</kbd> to delete the last image in the current image sequence.</p> 1858 1859 1860<div style="margin: auto;"> 1861 <h4><a id="density"></a>-density <em class="arg">width</em><br />-density <em class="arg">width</em>x<em class="arg">height</em></h4> 1862</div> 1863 1864<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the horizontal and vertical resolution of an image for rendering to devices.</td><td style='text-align:right;'></td></tr></table> 1865 1866<p>This option specifies the image resolution to store while encoding a raster image or the canvas resolution while rendering (reading) vector formats such as Postscript, PDF, WMF, and SVG into a raster image. Image resolution provides the unit of measure to apply when rendering to an output device or raster image. The default unit of measure is in dots per inch (DPI). The <a href="#units">-units</a> option may be used to select dots per centimeter instead.</p> 1867 1868<p>The default resolution is 72 dots per inch, which is equivalent to one point per pixel (Macintosh and Postscript standard). Computer screens are normally 72 or 96 dots per inch, while printers typically support 150, 300, 600, or 1200 dots per inch. To determine the resolution of your display, use a ruler to measure the width of your screen in inches, and divide by the number of horizontal pixels (1024 on a 1024x768 display).</p> 1869 1870<p>If the file format supports it, this option may be used to update the stored image resolution. Note that Photoshop stores and obtains image resolution from a proprietary embedded profile. If this profile is not stripped from the image, then Photoshop will continue to treat the image using its former resolution, ignoring the image resolution specified in the standard file header.</p> 1871 1872<p>The <a href="#density">-density</a> option sets an <em>attribute</em> and does not alter the underlying raster image. It may be used to adjust the rendered size for desktop publishing purposes by adjusting the scale applied to the pixels. To resize the image so that it is the same size at a different resolution, use the <a href="#resample">-resample</a> option.</p> 1873 1874<div style="margin: auto;"> 1875 <h4><a id="depth"></a>-depth <em class="arg">value</em></h4> 1876</div> 1877 1878<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>depth of the image.</td><td style='text-align:right;'></td></tr></table> 1879 1880<p>This the number of bits in a color sample within a pixel. Use this option to specify the depth of raw images whose depth is unknown such as GRAY, RGB, or CMYK, or to change the depth of any image after it has been read.</p> 1881 1882<div style="margin: auto;"> 1883 <h4><a id="descend"></a>-descend</h4> 1884</div> 1885 1886<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>obtain image by descending window hierarchy.</td><td style='text-align:right;'></td></tr></table> 1887 1888<div style="margin: auto;"> 1889 <h4><a id="deskew"></a>-deskew <em class="arg">threshold</em></h4> 1890</div> 1891 1892<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>straighten an image. A threshold of 40% works for most images.</td><td style='text-align:right;'></td></tr></table> 1893 1894<p>Use <a href="#set">-set</a> <kbd>option:deskew:auto-crop <em>width</em></kbd> to auto crop the image. The set argument is the pixel width of the image background (e.g 40).</p> 1895 1896<div style="margin: auto;"> 1897 <h4><a id="despeckle"></a>-despeckle</h4> 1898</div> 1899 1900<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>reduce the speckles within an image.</td><td style='text-align:right;'></td></tr></table> 1901 1902<div style="margin: auto;"> 1903 <h4><a id="direction"></a>-direction <em class="arg">type</em></h4> 1904</div> 1905 1906<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>render text right-to-left or left-to-right.</td><td style='text-align:right;'></td></tr></table> 1907 1908<div style="margin: auto;"> 1909 <h4><a id="displace"></a>-displace <em class="arg">horizontal-scale</em><br />-displace <em class="arg">horizontal-scale</em>x<em class="arg">vertical-scale</em></h4> 1910</div> 1911 1912<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>shift image pixels as defined by a displacement map.</td><td style='text-align:right;'>[<a href="/www/composite.html">composite</a>]</td></tr></table> 1913 1914<p>With this option, the 'overlay' image, and optionally the 'mask' image, 1915is used as a displacement map, which is used to displace the lookup of 1916what part of the 'background' image is seen at each point of the overlaid 1917area. Much like the displacement map is a 'lens' that redirects light shining 1918through it so as to present a distorted view the original 'background' image 1919behind it. </p> 1920 1921<p>Any perfect grey areas of the displacement map produce a zero 1922displacement of the image. Black areas produce the given maximum negative 1923displacement of the lookup point, while white produce a maximum positive 1924displacement of the lookup. </p> 1925 1926<p>Note that it is the lookup of the 'background' that is displaced, not a 1927displacement of the image itself. As such an area of the displacement map 1928containing 'white' will have the lookup point 'shifted' by a positive amount, 1929and thus generating a copy of the destination image to the right/downward from 1930the correct position. That is the image will look like it may have been 1931'shifted' in a negative left/upward direction. Understanding this is a very 1932important in understanding how displacement maps work. </p> 1933 1934<p>The given arguments define the maximum amount of displacement in pixels 1935that a particular map can produce. If the displacement scale is large enough 1936it is also possible to lookup parts of the 'background' image that lie well 1937outside the bounds of the displacement map itself. That is you could very 1938easily copy a section of the original image from outside the overlay area 1939into the overlay area. </p> 1940 1941<p>The '%' flag makes the displacement scale relative to the size of the 1942overlay image (100% = half width/height of image). Using '!' switches 1943percentage arguments to refer to the destination image size instead. 1944these flags were added as of IM v6.5.3-5.</p> 1945 1946<p>Normally a single grayscale displacement map is provided, which with the 1947given scaling values will determine a single direction (vector) in which 1948displacements can occur (positively or negatively). However, if you also 1949specify a third image which is normally used as a <em class="arg">mask</em>, 1950the <em class="arg">composite image</em> is used for horizontal X 1951displacement, while the <em class="arg">mask image</em> is used for vertical Y 1952displacement. This allows you to define completely different displacement 1953values for the X and Y directions, and allowing you to lookup any point within 1954the <em class="arg">scale</em> bounds. In other words each pixel can lookup 1955any other nearby pixel, producing complex 2 dimensional displacements, rather 1956than a simple 1 dimensional vector displacements. </p> 1957 1958<p>Alteratively rather than suppling two separate images, as of IM v6.4.4-0, 1959you can use the 'red' channel of the overlay image to specify the horizontal 1960or X displacement, and the 'green' channel for the vertical or Y displacement. 1961</p> 1962 1963<p>As of IM v6.5.3-5 any alpha channel in the overlay image is used as a 1964mask the transparency of the destination image. However areas outside the 1965overlaid areas will not be effected. </p> 1966 1967 1968<div style="margin: auto;"> 1969 <h4><a id="display"></a>-display <em class="arg">host:display[.screen]</em></h4> 1970</div> 1971 1972<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specifies the X server to contact.</td><td style='text-align:right;'>[<a href="/www/animate.html">animate</a>, <a href="/www/display.html">display</a>]</td></tr></table> 1973 1974<p>This option is used with convert for obtaining image or font from this X server. See <em class="arg">X(1)</em>.</p> 1975 1976<div style="margin: auto;"> 1977 <h4><a id="dispose"></a>-dispose <em class="arg">method</em></h4> 1978</div> 1979 1980<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>define the GIF disposal image setting for images that are being created or read in. </td><td style='text-align:right;'></td></tr></table> 1981 1982<p>The layer disposal method defines the way each the displayed image is to be 1983modified after the current 'frame' of an animation has finished being 1984displayed (after its 'delay' period), but before the next frame on an 1985animation is to be overlaid onto the display. </p> 1986 1987<p>Here are the valid methods:</p> 1988 1989<pre class="text"> 1990Undefined 0 No disposal specified (equivalent to '<kbd>none</kbd>'). 1991None 1 Do not dispose, just overlay next frame image. 1992Background 2 Clear the frame area with the background color. 1993Previous 3 Clear to the image prior to this frames overlay. 1994</pre> 1995 1996<p>You can also use the numbers given above, which is what the GIF format 1997uses internally to represent the above settings. </p> 1998 1999<p>To print a complete list of dispose methods, use <a href="#list">-list dispose</a>.</p> 2000 2001<p>Use <a href="#dispose" >+dispose</a>, turn off the setting and prevent 2002resetting the layer disposal methods of images being read in. </p> 2003 2004<p>Use <a href="#set">-set</a> '<kbd>dispose</kbd>' method to set the image 2005disposal method for images already in memory.</p> 2006 2007<div style="margin: auto;"> 2008 <h4><a id="dissimilarity-threshold"></a>-dissimilarity-threshold <em class="arg">value</em></h4> 2009</div> 2010 2011<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>maximum RMSE for subimage match (default 0.2).</td><td style='text-align:right;'>[<a href="/www/compare.html">compare</a>]</td></tr></table> 2012 2013 2014<div style="margin: auto;"> 2015 <h4><a id="dissolve"></a>-dissolve <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]</h4> 2016</div> 2017 2018<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>dissolve an image into another by the given percent.</td><td style='text-align:right;'>[<a href="/www/composite.html">composite</a>]</td></tr></table> 2019 2020<p>The opacity of the composite image is multiplied by the given percent, then 2021it is composited 'over' the main image. If <em class="arg">src_percent</em> 2022is greater than 100, start dissolving the main image so it becomes 2023transparent at a value of '<kbd class="arg">200</kbd>'. If both percentages 2024are given, each image are dissolved to the percentages given. </p> 2025 2026<p>Note that dissolve percentages do not add, two opaque images dissolved 2027'50,50', produce a 75% transparency. For a 50% + 50% blending of the two 2028images, you would need to use dissolve values of '50,100'. </p> 2029 2030<div style="margin: auto;"> 2031 <h4><a id="distort"></a>-distort <em class="arg">method arguments</em></h4> 2032</div> 2033 2034<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>distort an image, using the given <em class="arg">method</em> and its required <em class="arg">arguments</em>.</td><td style='text-align:right;'></td></tr></table> 2035 2036<p>The <em class="arg">arguments</em> is a single string containing a list 2037of floating point numbers separated by commas or spaces. The number of 2038and meaning of the floating point values depends on the distortion <em 2039class="arg">method</em> being used. </p> 2040 2041<p>Choose from these distortion types:</p> 2042 2043<table class="doc"> 2044 <tr valign="top"> 2045 <th align="left" style="width: 8%">Method</th> 2046 <th align="left">Description</th> 2047 </tr> 2048 2049 <tr valign="top"> 2050 <td valign="top"><kbd>ScaleRotateTranslate</kbd> 2051 <br/>or <kbd>SRT</kbd></td> 2052 <td valign="top"> 2053 Distort image by first scaling and rotating about a given 'center', 2054 before translating that 'center' to the new location, in that order. It 2055 is an alternative method of specifying a '<kbd>Affine</kbd>' type of 2056 distortion, but without shearing effects. It also provides a good way 2057 of rotating and displacing a smaller image for tiling onto a larger 2058 background (IE 2-dimensional animations). <br/> 2059 2060 The number of arguments determine the specific meaning of each 2061 argument for the scales, rotation, and translation operations. <br/> 2062 2063 <table style="margin-left:auto; margin-right:auto;"> 2064 <tr><td># </td><td>arguments meaning</td></tr> 2065 <tr><td>1:</td><td><em>Angle_of_Rotation</em></td></tr> 2066 <tr><td>2:</td><td><em>Scale Angle</em></td></tr> 2067 <tr><td>3:</td><td><em>X,Y Angle</em></td></tr> 2068 <tr><td>4:</td><td><em>X,Y Scale Angle</em></td></tr> 2069 <tr><td>5:</td> 2070 <td><em>X,Y ScaleX,ScaleY Angle</em></td></tr> 2071 <tr><td>6:</td> 2072 <td><em>X,Y Scale Angle NewX,NewY</em></td></tr> 2073 <tr><td>7:</td> 2074 <td><em>X,Y ScaleX,ScaleY Angle 2075 NewX,NewY</em></td></tr> 2076 </table> 2077 2078 This is actually an alternative way of specifying a 2 dimensional linear 2079 '<kbd>Affine</kbd>' or '<kbd>AffineProjection</kbd>' distortion. </td> </tr> 2080 2081 <tr valign="top"> 2082 <td valign="top"><kbd>Affine</kbd></td> 2083 <td valign="top"> 2084 Distort the image linearly by moving a list of at least 3 or more sets 2085 of control points (as defined below). Ideally 3 sets or 12 floating 2086 point values are given allowing the image to be linearly scaled, 2087 rotated, sheared, and translated, according to those three points. See 2088 also the related '<kbd>AffineProjection</kbd>' and '<kbd>SRT</kbd>' 2089 distortions. <br/> 2090 2091 More than 3 sets given control point pairs (12 numbers) is least 2092 squares fitted to best match a lineary affine distortion. If only 2 2093 control point pairs (8 numbers) are given a two point image translation 2094 rotation and scaling is performed, without any possible shearing, 2095 flipping or changes in aspect ratio to the resulting image. If only one 2096 control point pair is provides the image is only translated, (which may 2097 be a floating point non-integer translation). <br/> 2098 2099 This distortion does not include any form of perspective distortion. 2100 </td> 2101 2102 </tr> 2103 2104 <tr valign="top"> 2105 <td valign="top"><kbd>AffineProjection</kbd></td> 2106 <td valign="top"> 2107 Linearly distort an image using the given Affine Matrix of 6 2108 pre-calculated coefficients forming a set of Affine Equations to map 2109 the source image to the destination image. 2110 2111 <div style="text-align: center"><em> 2112 s<sub>x</sub>, r<sub>x</sub>, 2113 r<sub>y</sub>, s<sub>y</sub>, 2114 t<sub>x</sub>, t<sub>y</sub> 2115 </em></div> 2116 2117 See <a href="#affine" >-affine</a> setting for more detail, and 2118 meanings of these coefficients. <br/> 2119 2120 The distortions '<kbd>Affine</kbd>' and '<kbd>SRT</kbd>' provide 2121 alternative methods of defining this distortion, with ImageMagick doing 2122 the calculations needed to generate the required coefficients. You can 2123 see the internally generated coefficients, by using a <a 2124 href="#verbose" >-verbose</a> setting with those other varients. </td> 2125 2126 </tr> 2127 2128 <tr valign="top"> 2129 <td valign="top"><kbd>BilinearForward</kbd><br/> 2130 <kbd>BilinearReverse</kbd></td> 2131 <td valign="top"> 2132 Bilinear Distortion, given a minimum of 4 sets of coordinate pairs, or 2133 16 values (see below). Not that lines may not appear straight after 2134 distortion, though the distance between coordinates will remain 2135 consistent. <br/> 2136 2137 The '<kbd>BilinearForward</kbd>' is used to map rectangles to any 2138 quadrilateral, while the '<kbd>BilinearReverse</kbd>' form maps any 2139 quadrilateral to a rectangle, while preserving the straigth line edges 2140 in each case. <br/> 2141 2142 Note that '<kbd>BilinearForward</kbd>' can generate invalid pixels 2143 which will be colored using the <a href="#mattecolor" >-mattecolor</a> 2144 color setting. Also if the quadraterial becomes 'flipped' the image 2145 may dissappear. <br/> 2146 2147 There are future plans to produce a true Bilinear distortion that will 2148 attempt to map any quadrilateral to any other quadrilateral, while 2149 preserving edges (and edge distance ratios). 2150 2151 </td> 2152 </tr> 2153 2154 <tr valign="top"> 2155 <td valign="top"><kbd>Perspective</kbd></td> 2156 <td valign="top"> 2157 Perspective distort the images, using a list of 4 or more sets of 2158 control points (as defined below). More that 4 sets (16 numbers) of 2159 control points provide least squares fitting for more accurate 2160 distortions (for the purposes of image registration and panarama 2161 effects). Less than 4 sets will fall back to a '<kbd>Affine</kbd>' 2162 linear distortion. <br/> 2163 2164 Perspective Distorted images ensures that straight lines remain 2165 straight, but the scale of the distorted image will vary. The horizon 2166 is anti-aliased, and the 'sky' color may be set using the 2167 <a href="#mattecolor" >-mattecolor</a> setting. </td> 2168 </tr> 2169 2170 <tr valign="top"> 2171 <td valign="top"><kbd>PerspectiveProjection</kbd> </td> 2172 <td valign="top"> 2173 Do a '<kbd>Perspective</kbd>' distortion biased on a set of 8 2174 pre-calculated coefficients. You can get these coefficients by looking 2175 at the <a href="#verbose" >-verbose</a> output of a 2176 '<kbd>Prespective</kbd>' distortion, or by calculating them yourself. 2177 If the last two perspective scaling coefficients are zero, the 2178 remaining 6 represents a transposed 'Affine Matrix'. </td> 2179 2180 </tr> 2181 2182 <tr valign="top"> 2183 <td valign="top"><kbd>Arc</kbd></td> 2184 <td valign="top"> 2185 Arc the image (variation of polar mapping) over the angle given around 2186 a circle. <br/> 2187 <table width="90%" style = "margin-left: auto; margin-right: auto;"> 2188 <tr valign="top"><td>Argument</td> 2189 <td>Meaning</td></tr> 2190 <tr valign="top"><td><em>arc_angle</em></td> 2191 <td>The angle over which to arc the image side-to-side</td></tr> 2192 <tr valign="top"><td><em>rotate_angle</em></td> 2193 <td>Angle to rotate resulting image from vertical center</td></tr> 2194 <tr valign="top"><td><em>top_radius</em></td> 2195 <td>Set top edge of source image at this radius</td></tr> 2196 <tr valign="top"><td><em>bottom_radius</em> </td> 2197 <td>Set bottom edge to this radius (radial scaling)</td></tr> 2198 </table> 2199 2200 The resulting image is always resized to best fit the resulting image, 2201 (as if using <a href="#distort" >+distort</a>) while attempting to 2202 preserve scale and aspect ratio of the original image as much as 2203 possible with the arguments given by the user. All four arguments will 2204 be needed to change the overall aspect ratio of an 'Arc'ed image. <br/> 2205 2206 This a variation of a polar distortion designed to try to preserve the 2207 aspect ratio of the image rather than direct Cartesian to Polar 2208 conversion. </td> 2209 </tr> 2210 2211 <tr valign="top"> 2212 <td valign="top"><kbd>Polar</kbd></td> 2213 <td valign="top"> 2214 Like '<kbd>Arc</kbd>' but do a complete Cartesian to Polar mapping of 2215 the image. that is the height of the input image is mapped to the 2216 radius limits, while the width is wrapped around between the 2217 angle limits. <br/> 2218 2219 Arguments: <em>Rmax,Rmin CenterX,CenterY, start,end_angle</em> <br/> 2220 2221 All arguments are optional. With <em>Rmin</em> defaulting to zero, the 2222 center to the center of the image, and the angles going from -180 (top) 2223 to +180 (top). If <em>Rmax</em> is given the special value of 2224 '<code>0</code>', the the distance from the center to the nearest edge 2225 is used for the radius of the output image, which will ensure the whole 2226 image is visible (though scaled smaller). However a special value of 2227 '<code>-1</code>' will use the distance from the center to the furthest 2228 corner, This may 'clip' the corners from the input rectangular image, 2229 but will generate the exact reverse of a '<kbd>DePolar</kbd>' with 2230 the same arguments. <br/> 2231 2232 If the plus form of distort (<a href="#distort" >+distort</a>) is used 2233 output image center will default to <code>0,0</code> of the virtual 2234 canvas, and the image size adjusted to ensure the whole input image is 2235 made visible in the output image on the virtual canvas. </td> 2236 2237 </tr> 2238 2239 <tr valign="top"> 2240 <td valign="top"><kbd>DePolar</kbd></td> 2241 <td valign="top"> 2242 Uses the same arguments and meanings as a '<kbd>Polar</kbd>' distortion 2243 but generates the reverse Polar to Cartesian distortion. <br/> 2244 2245 The special <em>Rmax</em> setting of '<code>0</code>' may however clip 2246 the corners of the input image. However using the special 2247 <em>Rmax</em> setting of '<code>-1</code>' (maximum center to corner 2248 distance) will ensure the whole distorted image is preserved in the 2249 generated result, so that the same argument to '<kbd>Polar</kbd>' will 2250 reverse the distortion re-producing the original. 2251 2252 Note that as this distortion requires the area resampling of a circular 2253 arc, which can not be handled by the builtin EWA resampling function. 2254 As such the normal EWA filters are turned off. It is recommended some 2255 form of 'super-sampling' image processing technique be used to produce 2256 a high quality result. </td> 2257 2258 </tr> 2259 2260 <tr valign="top"> 2261 <td valign="top"><kbd>Barrel</kbd></td> 2262 <td valign="top"> 2263 Given the four coefficients (A,B,C,D) as defined by <a 2264 href="http://wiki.panotools.org/Lens_correction_model" >Helmut 2265 Dersch</a>, perform a barrell or pin-cushion distortion appropriate to 2266 correct radial lens distortions. That is in photographs, make straight 2267 lines straight again. <br/> 2268 2269 Arguments: <em>A B C</em> [ <em>D</em> [ 2270 <em>X</em> , <em>Y</em> ] ] <br/> 2271 or <em>A<sub>x</sub> B<sub>x</sub> C<sub>x</sub> D<sub>x</sub> 2272 A<sub>y</sub> B<sub>y</sub> C<sub>y</sub> D<sub>y</sub></em> 2273 [ <em>X</em> , <em>Y</em> ] <br/> 2274 So that it forms the function <br/> 2275 Rsrc = r * ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> + 2276 <em>C</em>*r + <em>D</em> )<br/> 2277 2278 Where <em>X</em>,<em>Y</em> is the optional center of the distortion 2279 (defaulting to the center of the image). <br/> 2280 The second form is typically used to distort images, rather than 2281 correct lens distortions. <br/> 2282 </td> 2283 2284 </tr> 2285 2286 <tr valign="top"> 2287 <td valign="top"><kbd>BarrelInverse</kbd></td> 2288 <td valign="top"> 2289 This is very simular to '<kbd>Barrel</kbd>' with the same set of 2290 arguments, and argument handling. However it uses the inverse 2291 of the radial polynomial, 2292 so that it forms the function <br/> 2293 Rsrc = r / ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> + 2294 <em>C</em>*r + <em>D</em> )<br/> 2295 Note that this is not the reverse of the '<kbd>Barrel</kbd>' 2296 distortion, just a different barrel-like radial distortion method. 2297 2298 </td> 2299 </tr> 2300 2301 <tr valign="top"> 2302 <td valign="top"><kbd>Shepards</kbd></td> 2303 <td valign="top"> 2304 Distort the given list control points (any number) using an Inverse 2305 Squared Distance Interpolation Method (<a 2306 href="http://en.wikipedia.org/wiki/Shepard%27s_method" >Shepards 2307 Method</a>). The control points in effect do 'localized' displacement 2308 of the image around the given control point (preserving the look and 2309 the rotation of the area near the control points. For best results 2310 extra control points should be added to 'lock' the positions of the 2311 corners, edges and other unchanging parts of the image, to prevent 2312 their movement. <br/> 2313 2314 The distortion has been likened to 'taffy pulling' using nails, or 2315 pins' stuck in a block of 'jelly' which is then moved to the new 2316 position, distorting te surface of the jelly. <br/> 2317 2318 Internally it is equivelent to generating a displacement map (see <a 2319 href="#displace" >-displace</a>) for source image color look-up using 2320 the <a href="#sparse-color" >-sparse-color</a> method of the same name. 2321 2322 </td> 2323 </tr> 2324 2325</table> 2326 2327<p>To print a complete list of distortion methods, use <a href="#list">-list 2328distort</a>.</p> 2329 2330<p>Many of the above distortion methods such as '<kbd>Affine</kbd>', 2331'<kbd>Perspective</kbd>', and '<kbd>Shepards</kbd>' use a list control points 2332defining how these points in the given image should be distorted in the 2333destination image. Each set of four floating point values represent a source 2334image coordinate, followed immediately by the destination image coordinate. 2335This produces a list of values such as...</p> 2336<div style="text-align: center"><em> 2337 U<sub>1</sub>,V<sub>1</sub> X<sub>1</sub>,Y<sub>1</sub> 2338 U<sub>2</sub>,V<sub>2</sub> X<sub>2</sub>,Y<sub>2</sub> 2339 U<sub>3</sub>,V<sub>3</sub> X<sub>3</sub>,Y<sub>3</sub> 2340 ... 2341 U<sub>n</sub>,V<sub>n</sub> X<sub>n</sub>,Y<sub>n</sub> 2342</em></div> 2343<p>where <em>U,V</em> on the source image is mapped to <em>X,Y</em> on the 2344destination image. </p> 2345 2346<p>For example, to warp an image using '<kbd>perspective</kbd>' distortion, 2347needs a list of at least 4 sets of coordinates, or 16 numbers. Here is the 2348perspective distortion of the built-in "rose:" image. Note how spaces were 2349used to group the 4 sets of coordinate pairs, to make it easier to read and 2350understand.</p> 2351 2352<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'> 2353convert rose: -virtual-pixel black \<br/> 2354 -distort Perspective '0,0,0,0 0,45,0,45 69,0,60,10 69,45,60,35' \<br/> 2355 rose_3d_rotated.gif</span></p> 2356<p>If more that the required number of coordinate pairs are given for 2357a distortion, the distortion method is 'least squares' fitted to produce the 2358best result for all the coordinate pairs given. If less than the ideal number 2359of points are given, the distort will generally fall back to a simpler form of 2360distortion that can handles the smaller number of coordinates (usally a linear 2361'<kbd>Affine</kbd>' distortion). </p> 2362 2363<p>By using more coordinates you can make use of image registration tool to 2364find matching coordinate pairs in overlapping images, so as to improve the 2365'fit' of the distortion. Of course a bad coordinate pair can also make the 2366'fit' worse. Caution is always advised. </p> 2367 2368<p>Colors are acquired from the source image according to the <a 2369href="#interpolate" >-interpolate</a> color lookup setting, when the image is 2370magnified. However if the viewed image is minified (image becomes smaller), 2371a special area resampling function (added ImageMagick v6.3.5-9), is used to 2372produce a higher quality image. For example you can use 2373a '<kbd>perspective</kbd>' distortion to view a infinitely tiled 'plane' all 2374the way to the horizon. </p> 2375 2376<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'> 2377convert -size 90x90 pattern:checkerboard -normalize -virtual-pixel tile \<br/> 2378 -distort perspective '0,0,5,45 89,0,45,46 0,89,0,89 89,89,89,89' \<br/> 2379 checks_tiled.jpg</span></p> 2380<p>Note that a infinitely tiled perspective images involving the horizon can 2381be very slow to generate due to the use of the high quality 'area resampling' 2382function (added ImageMagick v6.3.5-9). You can turn off 'area resampling' 2383using a <a href="#filter" >-filter</a> setting of '<kbd>point</kbd>' 2384(recommended if you plan to use super-sampling instead). </p> 2385 2386<p>If an image generates <i>invalid pixels</i>, such as the 'sky' in the last 2387'<kbd>perspective</kbd>' distortion example, <a href="#distort" >-distort</a> 2388will use the current <a href="#mattecolor" >-mattecolor</a> setting for these 2389pixels. If you do not what these pixels to be visible, set the color to match 2390the rest of the ground. </p> 2391 2392<p>The output image size will by default be the same as the input image. This 2393means that if the part of the distorted image falls outside the viewed area of 2394the 'distorted space', those parts is clipped and lost. However if you use 2395the plus form of the operator (<a href="#distort" >+distort</a>) the operator 2396will attempt (if possible) to show the whole of the distorted image, while 2397retaining a correct 'virtual canvas' offset, for image layering. This offset 2398may need to be removed using <a href="#repage" >+repage</a>, to remove if it 2399is unwanted. </p> 2400 2401<p>You can alternatively specify a special "<kbd><a href="#set" >-set</a> 2402option:distort:viewport {geometry_string}</kbd>" setting which will specify 2403the size and the offset of the generated 'viewport' image of the distorted 2404image space.</p> 2405 2406<p>Adding a "<kbd><a href="#set" >-set</a> option:distort:scale 2407{scale_factor}</kbd>" will scale the output image (viewport or otherwise) by 2408that factor without changing the viewed contents of the distorted image. This 2409can be used either for 'super-sampling' the image for a higher quality result, 2410or for panning and zooming around the image (with appropriate viewport 2411changes, or post-distort cropping and resizing). </p> 2412 2413<p>Setting <a href="#verbose" >-verbose</a> setting, will cause <a 2414href="#distort" >-distort</a> to attempt to output the internal coefficients, 2415and the <a href="#fx" >-fx</a> equivalent to the distortion, for expert study, 2416and debugging purposes. This many not be available for all distorts. </p> 2417 2418<p>Affine rotations and shears (such as '<kbd>SRT</kbd>' distortion), tend to 2419produce a cleaner result that the equivalent <a href="#rotate" >-rotate</a> 2420and/or <a href="#shear" >-shear</a> operation, with more control of due to the 2421above settings. It is algorithmically slower however, though that may not be 2422the case in ImageMagick's implementation. </p> 2423 2424 2425<div style="margin: auto;"> 2426 <h4><a id="dither"></a>-dither <em class="arg">method</em></h4> 2427</div> 2428 2429<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Apply a Riemersma or Floyd-Steinberg error diffusion dither to images when general color reduction is applied via an option, or automagically when saving to specific formats. This enabled by default. </td><td style='text-align:right;'></td></tr></table> 2430 2431<p>Dithering places two or more colors in neighboring pixels so that to the eye a closer approximation of the images original color is reproduced. This reduces the number of colors needed to reproduce the image but at the cost of a lower level pattern of colors. Error diffusion dithers can use any set of colors (generated or user defined) to an image. </p> 2432 2433<p>Dithering is turned on by default, to turn it off use the plus form of the 2434setting, <a href="#dither">+dither</a>. This will also also render PostScript 2435without text or graphic aliasing. Disabling dithering often (but not always) 2436leads to faster process, a smaller number of colors, but more cartoon like 2437image coloring. Generally resulting in 'color banding' effects in areas with 2438color gradients. </p> 2439 2440<p>The color reduction operators <a href="#colors">-colors</a>, <a 2441href="#monochrome">-monochrome</a>, <a href="#remap ">-remap</a>, and <a href="#posterize">-posterize</a>, apply dithering to images using the reduced color set they created. These operators are also used as part of automatic color reduction when saving images to formats with limited color support, such as <kbd>GIF:</kbd>, <kbd>XBM:</kbd>, and others, so dithering may also be used in these cases. </p> 2442 2443<p>Alternatively you can use <a href="#random-threshold">-random-threshold</a> to generate purely random dither. Or use <a href="#ordered-dither">-ordered-dither</a> to apply threshold mapped dither patterns, using uniform color maps, rather than specific color maps. </p> 2444 2445 2446<div style="margin: auto;"> 2447 <h4><a id="draw"></a>-draw <em class="arg">string</em></h4> 2448</div> 2449 2450<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Annotate an image with one or more graphic primitives.</td><td style='text-align:right;'></td></tr></table> 2451 2452<p>Use this option to annotate or decorate an image with one or more graphic primitives. The primitives include shapes, text, transformations, and pixel operations.</p> 2453 2454<p>The shape primitives:</p> 2455 2456<pre class="text"> 2457 point x,y 2458 line x0,y0 x1,y1 2459 rectangle x0,y0 x1,y1 2460 roundRectangle x0,y0 x1,y1 wc,hc 2461 arc x0,y0 x1,y1 a0,a1 2462 ellipse x0,y0 rx,ry a0,a1 2463 circle x0,y0 x1,y1 2464 polyline x0,y0 ... xn,yn 2465 polygon x0,y0 ... xn,yn 2466 bezier x0,y0 ... xn,yn 2467 path path specification 2468 image operator x0,y0 w,h filename 2469</pre> 2470 2471<p>The text primitive:</p> 2472 2473<pre class="text"> 2474 text x0,y0 string 2475</pre> 2476<p>The text gravity primitive:</p> 2477 2478<pre class="text"> 2479 gravity NorthWest, North, NorthEast, West, Center, 2480 East, SouthWest, South, or SouthEast 2481</pre> 2482 2483<p>The text gravity primitive only affects the placement of text and does not interact with the other primitives. It is equivalent to using the <a href="#gravity">-gravity</a> command-line option, except that it is limited in scope to the <a href="#draw">-draw</a> option in which it appears.</p> 2484 2485<p>The transformation primitives:</p> 2486 2487<pre class="text"> 2488 rotate degrees 2489 translate dx,dy 2490 scale sx,sy 2491 skewX degrees 2492 skewY degrees 2493</pre> 2494 2495<p>The pixel operation primitives:</p> 2496 2497<pre class="text"> 2498 color x0,y0 method 2499 matte x0,y0 method 2500</pre> 2501 2502<p>The shape primitives are drawn in the color specified by the preceding <a href="#fill">-fill</a> setting. For unfilled shapes, use <a href="#fill">-fill none</a>. You can optionally control the stroke (the "outline" of a shape) with the <a href="#stroke">-stroke</a> and <a href="#strokewidth">-strokewidth</a> settings.</p> 2503 2504<p>A <kbd>point</kbd> primitive is specified by a single <em>point</em> in the pixel plane, that is, by an ordered pair of integer coordinates, <em>x</em>,<em>y</em>. (As it involves only a single pixel, a <kbd>point</kbd> primitive is not affected by <a href="#stroke">-stroke</a> or <a href="#strokewidth">-strokewidth</a>.)</p> 2505 2506<p>A <kbd>line</kbd> primitive requires a start point and end point.</p> 2507 2508<p>A <kbd>rectangle</kbd> primitive is specified by the pair of points at the upper left and lower right corners.</p> 2509 2510<p>A <kbd>roundRectangle</kbd> primitive takes the same corner points as a <kbd>rectangle</kbd> followed by the width and height of the rounded corners to be removed.</p> 2511 2512<p>The <kbd>circle</kbd> primitive makes a disk (filled) or circle (unfilled). Give the center and any point on the perimeter (boundary).</p> 2513 2514<p>The <kbd>arc</kbd> primitive is used to inscribe an elliptical segment in to a given rectangle. An <kbd>arc</kbd> requires the two corners used for <kbd>rectangle</kbd> (see above) followed by the start and end angles of the arc of the segment segment (e.g. 130,30 200,100 45,90). The start and end points produced are then joined with a line segment and the resulting segment of an ellipse is filled.</p> 2515 2516<p>Use <kbd>ellipse</kbd> to draw a partial (or whole) ellipse. Give the center point, the horizontal and vertical "radii" (the <em>semi-axes</em> of the ellipse) and start and end angles in degrees (e.g. 100,100 100,150 0,360).</p> 2517 2518<p>The <kbd>polyline</kbd> and <kbd>polygon</kbd> primitives require three or more points to define their perimeters. A <kbd>polyline</kbd> is simply a <kbd>polygon</kbd> in which the final point is not stroked to the start point. When unfilled, this is a <em>polygonal line</em>. If the <a href="#stroke">-stroke</a> setting is <kbd>none</kbd> (the default), then a <kbd>polyline</kbd> is identical to a <kbd>polygon</kbd>. 2519</p> 2520 2521<p>A <em>coordinate</em> is a pair of integers separated by a space or optional comma. </p> 2522 2523<p>As an example, to define a circle centered at 100,100 that extends to 150,150 use:</p> 2524 2525<p class="crtsnip"> 2526 -draw 'circle 100,100 150,150' 2527</p> 2528 2529<p>The <kbd>Bezier</kbd> primitive creates a spline curve and requires three or points to define its shape. The first and last points are the <em>knots</em> and these points are attained by the curve, while any intermediate coordinates are <em>control points</em>. If two control points are specified, the line between each end knot and its sequentially respective control point determines the tangent direction of the curve at that end. If one control point is specified, the lines from the end knots to the one control point determines the tangent directions of the curve at each end. If more than two control points are specified, then the additional control points act in combination to determine the intermediate shape of the curve. In order to 2530draw complex curves, it is highly recommended either to use the <kbd>path</kbd> primitive or to draw multiple four-point bezier segments with the start and end knots of each successive segment repeated. For example:</p> 2531 2532<p class="crtsnip"> 2533 -draw 'bezier 20,50 45,100 45,0 70,50' 2534</p> 2535<p class="crtsnip"> 2536 -draw 'bezier 70,50 95,100 95,0 120,50' 2537</p> 2538 2539 2540<p>A <kbd>path</kbd> represents an outline of an object, defined in terms of moveto (set a new current point), lineto (draw a straight line), curveto (draw a Bezier curve), arc (elliptical or circular arc) and closepath (close the current shape by drawing a line to the last moveto) elements. Compound paths (i.e., a path with subpaths, each consisting of a single moveto followed by one or more line or curve operations) are possible to allow effects such as <em>donut holes</em> in objects. (See <a href="http://www.w3.org/TR/SVG/paths.html">Paths</a>.)</p> 2541 2542<p>Use <kbd>image</kbd> to composite an image with another image. Follow the image keyword with the composite operator, image location, image size, and filename:</p> 2543 2544<p class="crtsnip"> 2545 -draw 'image SrcOver 100,100 225,225 image.jpg' 2546</p> 2547 2548<p>You can use 0,0 for the image size, which means to use the actual 2549dimensions found in the image header. Otherwise, it is scaled to the given 2550dimensions. See <a href="/www/compose.html">Alpha Compositing</a> for 2551a detailed discussion of alpha composition methods that are available. </p> 2552 2553<p>Use <kbd>text</kbd> to annotate an image with text. Follow the text coordinates with a string. If the string has embedded spaces, enclose it in single or double quotes.</p> 2554 2555<p>For example, the following annotates the image with <kbd>Works like magick!</kbd> for an image titled <kbd>bird.miff</kbd>. </p> 2556 2557<p class="crtsnip"> 2558 -draw 'text 100,100 "Works like magick!"' 2559</p> 2560 2561<p>See the <a href="#annotate">-annotate</a> option for another convenient way to annotate an image with text.</p> 2562 2563<p>The <kbd>rotate</kbd> primitive rotates subsequent shape primitives and text primitives about the origin of the main image. If the <a href="#region">-region</a> option precedes the <a href="#draw">-draw</a> option, the origin for transformations is the upper left corner of the region.</p> 2564 2565<p>The <kbd>translate</kbd> primitive translates subsequent shape and text primitives.</p> 2566 2567<p>The <kbd>scale</kbd> primitive scales them.</p> 2568 2569<p>The <kbd>skewX</kbd> and <kbd>skewY</kbd> primitives skew them with respect to the origin of the main image or the region.</p> 2570 2571<p>The transformations modify the current affine matrix, which is initialized from the initial affine matrix defined by the <a href="#affine">-affine</a> option. Transformations are cumulative within the <a href="#draw">-draw</a> option. The initial affine matrix is not affected; that matrix is only changed by the appearance of another <a href="#affine">-affine</a> option. If another <a href="#draw">-draw</a> option appears, the current affine matrix is reinitialized from the initial affine 2572matrix.</p> 2573 2574<p>Use the <kbd>color</kbd> primitive to change the color of a pixel to the fill color (see <a href="#fill">-fill</a>). Follow the pixel coordinate with a method:</p> 2575 2576<pre class="text"> 2577 point 2578 replace 2579 floodfill 2580 filltoborder 2581 reset 2582</pre> 2583 2584<p>Consider the target pixel as that specified by your coordinate. The <kbd>point</kbd> method recolors the target pixel. The <kbd>replace</kbd> method recolors any pixel that matches the color of the target pixel. <kbd>Floodfill</kbd> recolors any pixel that matches the color of the target pixel and is a neighbor, whereas <kbd>filltoborder</kbd> recolors any neighbor pixel that is not the border color. Finally, <kbd>reset</kbd> recolors all pixels.</p> 2585 2586<p>Use <kbd>matte</kbd> to the change the pixel matte value to transparent. Follow the pixel coordinate with a method (see the <kbd>color</kbd> primitive for a description of methods). The <kbd>point</kbd> method changes the matte value of the target pixel. The <kbd>replace</kbd> method changes the matte value of any pixel that matches the color of the target pixel. <kbd>Floodfill</kbd> changes the matte value of any pixel that matches the color of the target pixel and is a neighbor, whereas <kbd>filltoborder</kbd> changes the matte value of any neighbor pixel that is not the border color (<a href="#bordercolor">-bordercolor</a>). Finally <kbd>reset</kbd> changes the matte value of all pixels.</p> 2587 2588<p>You can set the primitive color, font, and font bounding box color with <a href="#fill">-fill</a>, <a href="#font">-font</a>, and <a href="#box">-box</a> respectively. Options are processed in command line order so be sure to use these options <em>before</em> the <a href="#draw">-draw</a> option.</p> 2589 2590<p>Strings that begin with a number must be quoted (e.g. use '1.png' rather than 1.png).</p> 2591 2592<p>Drawing primitives conform to the <a href="/www/magick-vector-graphics.html">Magick Vector Graphics</a> format.</p> 2593 2594<div style="margin: auto;"> 2595 <h4><a id="duplicate"></a>-duplicate <em class="arg">count,indexes</em></h4> 2596</div> 2597 2598<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>duplicate an image one or more times.</td><td style='text-align:right;'></td></tr></table> 2599 2600<p>Specify the count and the image to duplicate by its index in the sequence. The first image is index 0. Negative indexes are relative to the end of the sequence, for example, -1 represents the last image of the sequence. Specify a range of images with a dash (e.g. 0-4). Separate indexes with a comma (e.g. 0,2). Use <kbd>+duplicate</kbd> to duplicate the last image in the current image sequence.</p> 2601 2602<div style="margin: auto;"> 2603 <h4><a id="edge"></a>-edge <em class="arg">radius</em></h4> 2604</div> 2605 2606<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>detect edges within an image.</td><td style='text-align:right;'></td></tr></table> 2607 2608<div style="margin: auto;"> 2609 <h4><a id="emboss"></a>-emboss <em class="arg">radius</em></h4> 2610</div> 2611 2612<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>emboss an image.</td><td style='text-align:right;'></td></tr></table> 2613 2614<div style="margin: auto;"> 2615 <h4><a id="encipher"></a>-encipher <em class="arg">filename</em></h4> 2616</div> 2617 2618<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Encipher pixels for later deciphering by <a href="#decipher">-decipher</a>.</td><td style='text-align:right;'></td></tr></table> 2619 2620<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p> 2621 2622<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p> 2623 2624 2625 2626<div style="margin: auto;"> 2627 <h4><a id="encoding"></a>-encoding <em class="arg">type</em></h4> 2628</div> 2629 2630<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>specify the text encoding.</td><td style='text-align:right;'></td></tr></table> 2631 2632<p>Choose from <kbd>AdobeCustom</kbd>, <kbd>AdobeExpert</kbd>, <kbd>AdobeStandard</kbd>, <kbd>AppleRoman</kbd>, <kbd>BIG5</kbd>, <kbd>GB2312</kbd>, <kbd>Latin 2</kbd>, <kbd>None</kbd>, <kbd>SJIScode</kbd>, <kbd>Symbol</kbd>, <kbd>Unicode</kbd>, <kbd>Wansung</kbd>.</p> 2633 2634<div style="margin: auto;"> 2635 <h4><a id="endian"></a>-endian <em class="arg">type</em></h4> 2636</div> 2637 2638<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specify endianness (<kbd>MSB</kbd> or <kbd>LSB</kbd>) of the image.</td><td style='text-align:right;'></td></tr></table> 2639 2640<p>To print a complete list of endian types, use the <a href="#list">-list endian</a> option.</p> 2641 2642<p>Use <a href="#endian">+endian</a> to revert to unspecified endianness.</p> 2643 2644 2645<div style="margin: auto;"> 2646 <h4><a id="enhance"></a>-enhance</h4> 2647</div> 2648 2649<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Apply a digital filter to enhance a noisy image.</td><td style='text-align:right;'></td></tr></table> 2650 2651 2652<div style="margin: auto;"> 2653 <h4><a id="equalize"></a>-equalize</h4> 2654</div> 2655 2656<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>perform histogram equalization on the image channel-by-channel.</td><td style='text-align:right;'></td></tr></table> 2657 2658<p>To perform histogram equalization on all channels in concert, transform the image into some other color space, such as HSL, OHTA, YIQ or YUV, then equalize the appropriate intensity-like channel, then convert back to RGB.</p> 2659 2660<p>For example using HSL, we have: ... <kbd>-colorspace HSL -channel lightness -equalize -colorspace RGB</kbd> ...</p> 2661 2662<p>For YIQ, YUV and OHTA use the red channel. For example, OHTA is a principal components transformation that puts most of the information in the first channel. Here we have ... <kbd>-colorspace OHTA -channel red -equalize -colorspace RGB</kbd> ...</p> 2663 2664<div style="margin: auto;"> 2665 <h4><a id="evaluate"></a>-evaluate <em class="arg">operator value</em></h4> 2666</div> 2667 2668<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Alter channel pixels by evaluating an arithmetic, relational, or logical expression.</td><td style='text-align:right;'></td></tr></table> 2669 2670<p>(See the <a href="#function" >-function</a> operator for some multi-parameter functions. See the <a href="#fx" >-fx</a> operator if more elaborate calculations are needed.)</p> 2671 2672<p>The behaviors of each <em class="arg">operator</em> are summarized in the following list. For brevity, the numerical value of a "pixel" referred to below is the value of the corresponding channel of that pixel, while a "normalized pixel" is that number divided by the maximum (installation-dependent) value <em class="QR">QuantumRange</em>. (If normalized pixels are used, they are restored, following the other calculations, to the full range by multiplying by <em class="QR">QuantumRange</em>.)</p> 2673 2674<table class="doc"> 2675 <col width="25%" /> 2676 <col width="75%" /> 2677 <thead> 2678 <tr> 2679 <th><em class="arg">operator</em></th> 2680 <th>Summary (see further below for details)</th> 2681 </tr> 2682 </thead> 2683 <tbody> 2684 2685 <tr><td>Abs </td> <td>Add <em class="arg">value</em> to pixels and return absolute value. </td></tr> 2686 <tr><td>Add </td> <td>Add <em class="arg">value</em> to pixels. </td></tr> 2687 <tr><td>AddModulus </td> <td>Add <em class="arg">value</em> to pixels modulo <em class="QR">QuantumRange</em>.</td></tr> 2688 <tr><td>And </td> <td>Binary AND of pixels with <em class="arg">value</em>.</td></tr> 2689 <tr><td>Cos, Cosine </td> <td>Apply cosine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr> 2690 <tr><td>Divide </td> <td>Divide pixels by <em class="arg">value</em>.</td></tr> 2691 <tr><td>Exp </td> <td>base-e exponential function</td></tr> 2692 <tr><td>Exponential </td> <td>base-e exponential function</td></tr> 2693 <tr><td>LeftShift </td> <td>Shift the pixel values left by <em class="arg">value</em> bits (i.e., multiply pixels by 2<sup><em class="arg">value</em></sup>).</td></tr> 2694 <tr><td>Log </td> <td>Apply scaled logarithm to normalized pixels.</td></tr> 2695 <tr><td>Max </td> <td>Clip pixels at lower bound <em class="arg">value</em>.</td></tr> 2696 <tr><td>Mean </td> <td>Add the <em class="arg">value</em> and divide by 2.</td></tr> 2697 <tr><td>Median </td> <td>Choose the median value from an image sequence.</td></tr> 2698 <tr><td>Min </td> <td>Clip pixels at upper bound <em class="arg">value</em>.</td></tr> 2699 <tr><td>Multiply </td> <td>Multiply pixels by <em class="arg">value</em>.</td></tr> 2700 <tr><td>Or </td> <td>Binary OR of pixels with <em class="arg">value</em>.</td></tr> 2701 <tr><td>Pow </td> <td>Raise normalized pixels to the power <em class="arg">value</em>.</td></tr> 2702 <tr><td>RightShift </td> <td>Shift the pixel values right by <em class="arg">value</em> bits (i.e., divide pixels by 2<sup><em class="arg">value</em></sup>).</td></tr> 2703 <tr><td>Set </td> <td>Set pixel equal to <em class="arg">value</em>.</td></tr> 2704 <tr><td>Sin, Sine </td> <td>Apply sine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr> 2705 <tr><td>Subtract </td> <td>Subtract <em class="arg">value</em> from pixels.</td></tr> 2706 <tr><td>Xor </td> <td>Binary XOR of pixels with <em class="arg">value.</em></td></tr> 2707 2708 <tr><td> </td></tr> 2709 2710 <tr><td>Gaussian-noise</td></tr> 2711 <tr><td>Impulse-noise</td></tr> 2712 <tr><td>Laplacian-noise</td></tr> 2713 <tr><td>Multiplicative-noise</td> <td>(These are equivalent to the corresponding <a href="#noise" >-noise</a> operators.)</td></tr> 2714 <tr><td>PoissonNoise</td></tr> 2715 <tr><td>Uniform-noise</td></tr> 2716 2717 <tr><td> </td></tr> 2718 2719 <tr><td>Threshold </td> <td>Threshold pixels larger than <em class="arg">value</em>.</td></tr> 2720 <tr><td>ThresholdBlack </td> <td>Threshold pixels to zero values equal to or below <em class="arg">value</em>.</td></tr> 2721 <tr><td>ThresholdWhite </td> <td>Threshold pixels to maximum values above <em class="arg">value</em>. </td></tr> 2722 </tbody> 2723 </table> 2724 2725<p>The specified functions are applied only to each previously set <a 2726href="#channel" >-channel</a> in the image. If necessary, the results of the 2727calculations are truncated (clipped) to fit in the interval [0, <em 2728class="QR">QuantumRange</em>]. The transparency channel of the image is 2729represented as a 'alpha' values (0 = fully transparent), so, for example, a 2730<kbd>Divide</kbd> by 2 of the alpha channel will make the image 2731semi-transparent. Append the percent symbol '<kbd>%</kbd>' to specify a value 2732as a percentage of the <em class="QR">QuantumRange</em>.</p> 2733 2734<p>To print a complete list of <a href="#evaluate">-evaluate</a> operators, use 2735<a href="#list">-list evaluate</a>.</p> 2736 2737<p>The results of the <kbd>Add</kbd>, <kbd>Subtract</kbd> and 2738<kbd>Multiply</kbd> methods can also be achieved using either the <a 2739href="#level" >-level</a> or the <a href="#level" >+level</a> operator, with 2740appropriate argument, to linearly modify the overall range of color values. 2741Please note, however, that <a href="#level" >-level</a> treats transparency as 2742'matte' values (0 = opaque), while <a href="#level" >-evaluate</a> works with 2743'alpha' values.</p> 2744 2745<p><kbd>AddModulus</kbd> has been added as of ImageMagick 6.4.8-4 and provides addition modulo the <em class="QR">QuantumRange</em>. It is therefore equivalent to <kbd>Add</kbd> unless the resulting pixel value is outside the interval [0, <em class="QR">QuantumRange</em>]. </p> 2746 2747<p><kbd>Exp or Exponential</kbd> has been added as of ImageMagick 6.6.5-1 and works on normalized pixel values. The <em class="arg">value</em> used with <kbd>Exp</kbd> should be negative so as to produce a decaying exponential function. Non-negative values will always produce results larger unity and thus outside the interval [0, <em class="QR">QuantumRange</em>]. The formula is expressed below. </p> 2748 2749 <div style="text-align:center;"> 2750 exp(<em class="arg">value</em> × <b><em>u</em></b>) 2751 </div> 2752 2753<p> If the input image is squared, for example, using <a 2754href="#-function" >-function polynomial "2 0 0"</a>, then a decaying Gaussian function will be the result.</p> 2755 2756<p><kbd>Log</kbd> has been added as of ImageMagick 6.4.2-1 and works on normalized pixel values. This a <em>scaled</em> log function. The <em class="arg">value</em> used with <kbd>Log</kbd> provides a <em>scaling factor</em> that adjusts the curvature in the graph of the log function. The formula applied to a normalized value <b><em>u</em></b> is below. </p> 2757 2758 <div style="text-align:center;"> 2759 log(<em class="arg">value</em> × <b><em>u</em></b> + 1) / log(<em class="arg">value</em> + 1) 2760 </div> 2761 2762<p><kbd>Pow</kbd> has been added as of ImageMagick 6.4.1-9, and works on 2763normalized pixel values. Note that <kbd>Pow</kbd> is related to the <a 2764href="#gamma" >-gamma</a> operator. For example, <b>-gamma 2</b> is equivalent 2765to <b>-evaluate pow 0.5</b>, i.e., a 'square root' function. The value used 2766with <a href="#gamma" >-gamma</a> is simply the reciprocal of the value used 2767with <kbd>Pow</kbd>.</p> 2768 2769<p><kbd>Cosine</kbd> and <kbd>Sine</kbd> was added as of IM v6.4.8-8 and 2770converts the image values into a value according to a (co)sine wave function. 2771The synonyms <kbd>Cos</kbd> and <kbd>Sin</kbd> may also be used. The output 2772is biased 50% and normalized by 50% so as to fit in the respective color value 2773range. The <em class="arg">value</em> scaling of the <em>period</em> of the 2774function (its frequency), and thus determines the number of 'waves' that will 2775be generated over the input color range. For example, if the <em 2776class="arg">value</em> is 1, the effective period is simply the <em 2777class="QR">QuantumRange</em>; but if the <em class="arg">value</em> is 2, 2778then the effective period is the <em>half</em> the <em 2779class="QR">QuantumRange</em>.</p> 2780 2781 <div style="text-align:center;"> 2782 0.5 + 0.5 × cos(2 π <b><em>u</em></b> × <em class="arg">value</em>). 2783 </div> 2784 2785<p>See also the <a href="#function" >-function</a> operator, which is a 2786multi-value version of evaluate. </p> 2787 2788<div style="margin: auto;"> 2789 <h4><a id="evaluate-sequence"></a>-evaluate-sequence <em class="arg">operator</em></h4> 2790</div> 2791 2792<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Alter channel pixels by evaluating an arithmetic, relational, or logical expression over a sequence of images.</td><td style='text-align:right;'></td></tr></table> 2793 2794<div style="margin: auto;"> 2795 <h4><a id="extent"></a>-extent <em class="arg">geometry</em></h4> 2796</div> 2797 2798<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the image size and offset.</td><td style='text-align:right;'></td></tr></table> 2799 2800<p>If the image is enlarged, unfilled areas are set to the background color. To position the image, use offsets in the <em class="arg">geometry</em> specification or precede with a <a href="#gravity">-gravity</a> setting. To specify how to compose the image with the background, use <a href="#compose" >-compose</a>.</p> 2801<p>This command reduces or expands a JPEG image to fit on an 800x600 2802display. If the aspect ratio of the input image isn't exactly 4:3, then the 2803image is centered on an 800x600 black canvas: </p> 2804 2805<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert input.jpg -resize 800x600 -background black -compose Copy \ <br /> -gravity center -extent 800x600 -quality 92 output.jpg</span></p> 2806 2807 2808<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 2809 2810<div style="margin: auto;"> 2811 <h4><a id="extract"></a>-extract <em class="arg">geometry</em></h4> 2812</div> 2813 2814<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Extract the specified area from image.</td><td style='text-align:right;'></td></tr></table> 2815 2816<p>This option is most useful for extracting a subregion of a very large raw image. Note that these two commands are equivalent:</p> 2817 2818<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 -extract 640x480+1280+960 \ <br/> image.rgb image.png</span><span class='crtout'></span><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 'image.rgb[640x480+1280+960]' \ <br/> image.rgb image.png</span></p><p>If you omit the offsets, as in</p> 2819 2820<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 -extract 640x480 \ <br/> image.rgb image.png</span></p> 2821<p>the image is <em>resized</em> to the specified dimensions instead, 2822equivalent to:</p> 2823 2824<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 -resize 640x480 image.rgb image.png</span></p> 2825<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 2826 2827<div style="margin: auto;"> 2828 <h4><a id="family"></a>-family <em class="arg">fontFamily</em></h4> 2829</div> 2830 2831<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set a font family for text.</td><td style='text-align:right;'></td></tr></table> 2832 2833<p>This setting suggests a font family that ImageMagick should try to use for rendering text. If the family can be found it is used; if not, a default font (e.g., "Arial") or a family known to be similar is substituted (e.g., "Courier" might be used if "System" is requested but not found). 2834</p> 2835 2836<p>For other settings that affect fonts, see the options <a href="#font">-font</a>, <a href="#stretch">-stretch</a>, <a href="#style">-style</a>, and <a href="#weight">-weight</a>. 2837</p> 2838 2839<div style="margin: auto;"> 2840 <h4><a id="features"></a>-features <em class="arg">distance</em></h4> 2841</div> 2842 2843<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>display features for each channel in the image in each of four directions (horizontal, vertical, left and right diagonals) for the specified distance.</td><td style='text-align:right;'></td></tr></table> 2844 2845<div style="margin: auto;"> 2846 <h4><a id="fft"></a>-fft</h4> 2847</div> 2848 2849<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>implements the forward discrete Fourier transform (DFT).</td><td style='text-align:right;'></td></tr></table> 2850 2851<p>This option is new as of ImageMagick 6.5.4-3 (and now working for Windows users in ImageMagick 6.6.0-9). It transforms an image from the normal (spatial) domain to the frequency domain. In the frequency domain, an image is represented as a superposition of complex sinusoidal waves of varying amplitudes. The image x and y coordinates are the possible frequencies along the x and y directions, respectively, and the pixel intensity values are complex numbers that correspond to the sinusoidal wave amplitudes. See for example, <a href="http://en.wikipedia.org/wiki/Fourier_transform">Fourier Transform</a>, <a href="http://en.wikipedia.org/wiki/DFT">Discrete Fourier Transform</a> and <a href="http://en.wikipedia.org/wiki/FFT">Fast Fourier Transform</a>.</p> 2852 2853<p>A single image name is provided as output for this option. However, the output result will have two components. It is either a two-frame image or two separate images, depending upon whether the image format specified supports multi-frame images. The reason that we get a dual output result is because the frequency domain represents an image using complex numbers, which cannot be visualized directly. Therefore, the complex values are automagically separated into a two-component image representation. The first component is the magnitude of the complex number and the second is the phase of the complex number. See for example, <a href="http://en.wikipedia.org/wiki/Complex_numbers">Complex Numbers</a>.</p> 2854 2855<p>The magnitude and phase component images must be specified using image formats that do not limit the color or compress the image. Thus, MIFF, TIF, PFM, EXR and PNG are the recommended image formats to use. All of these formats, except PNG support multi-frame images. So for example,</p> 2856 2857<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -fft fft_image.miff</span></p> 2858<p>generates a magnitude image as <kbd>fft_image.miff[0]</kbd> and a phase image as <kbd>fft_image.miff[1]</kbd>. Similarly,</p> 2859 2860<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -fft fft_image.png</span></p> 2861<p>generates a magnitude image as <kbd>fft_image-0.png</kbd> and a phase image as <kbd>fft_image-1.png</kbd>. If you prefer this representation, then you can force any of the other formats to produce two output images by including <a href="#adjoin">+adjoin</a> following -fft in the command line.</p> 2862 2863<p>The input image can be any size, but if not square and even-dimensioned, it is padded automagically to the larger of the width or height of the input image and to an even number of pixels. The padding will occur at the bottom and/or right sides of the input image. The resulting output magnitude and phase images is square at this size. The kind of padding relies on the <a href="#virtual-pixel">-virtual-pixel</a> setting.</p> 2864 2865<p>Both output components will have dynamic ranges that fit within [0, <em class="QR">QuantumRange</em>], so that HDRI need not be enabled. Phase values nominally range from 0 to 2*π, but for non-HDRI compilations of ImageMagick, the phase image is scaled to span the full dynamic range. The magnitude image is not scaled and thus generally will contain very small values. As such, the image normally will appear totally black. In order to view any detail, the magnitude image typically is enhanced with a log function into what is usually called the spectrum. A log function is used to enhance the darker values more in comparison to the lighter values. This can be done, for example, as follows:</p> 2866 2867<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert fft_image.miff[0] -contrast-stretch 0 \ <br /> 2868 -evaluate log 1000 fft_image_spectrum.png</span></p> 2869<p>where the <a href="#contrast-stretch">-contrast-stretch</a> 0 is used to scale the image to full dynamic range, first. The argument to the <a href="#evaluate">-evaluate</a> log typically is specified between 100 and 10,000, depending upon the amount of detail that one wants to bring out in the spectrum. Larger values produce more visible detail. Too much detail, however, may hide the important features.</p> 2870 2871<p>The <a href="http://www.fftw.org/">FFTW</a> delegate library is required to use <a href="#fft">-fft</a>.</p> 2872 2873<p>Use <a href="#fft">+fft</a> to produce two output images that are the real and imaginary components of the complex valued Fourier transform.</p> 2874 2875<p>However, as the real and imaginary components can contain negative values, this requires that IM be configured with HDRI enabled. In this case, you must use either MIFF, TIF or PFM formats for the real and imaginary component results, since they are formats that preserve both negative and fractional values without clipping them or truncating the fractional part.</p> 2876 2877<p>The real and imaginary component images resulting from <a href="#fft">+fft</a> is also square, even dimensioned images due to the same padding that was discussed above for the magnitude and phase component images.</p> 2878 2879<p>See the discussion on HDRI implementations of ImageMagick on the page 2880<a href="/www/high-dynamic-range.html">High Dynamic-Range Images</a>. For more about HDRI go the ImageMagick <a href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this <a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a> entry. 2881</p> 2882 2883 2884<div style="margin: auto;"> 2885 <h4><a id="fill"></a>-fill <em class="arg">color</em></h4> 2886</div> 2887 2888<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>color to use when filling a graphic primitive.</td><td style='text-align:right;'></td></tr></table> 2889 2890<p>This option accepts a color name, a hex color, or a numerical RGB, RGBA, HSL, HSLA, CMYK, or CMYKA specification. See <a href="/www/color.html">Color Names</a> for a description of how to properly specify the color argument.</p> 2891 2892<p>Enclose the color specification in quotation marks to prevent the "#" or the parentheses from being interpreted by your shell.</p> 2893 2894<p>For example,</p> 2895 2896<p class="crtsnip"> 2897 -fill blue 2898</p> 2899<p class="crtsnip"> 2900 -fill "#ddddff" 2901</p> 2902<p class="crtsnip"> 2903 -fill "rgb(255,255,255)" 2904</p> 2905 2906<p>See <a href="#draw">-draw</a> for further details.</p> 2907 2908<p>To print a complete list of color names, use the <a href="#list">-list color</a> option.</p> 2909 2910<div style="margin: auto;"> 2911 <h4><a id="filter"></a>-filter <em class="arg">type</em></h4> 2912</div> 2913 2914<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Use this <em class="arg">type</em> of filter when resizing or 2915distorting an image.</td><td style='text-align:right;'></td></tr></table> 2916 2917<p>Use this option to affect the resizing operation of an image during 2918operations such as <a href="#resize">-resize</a> and <a href="#distort" 2919>-distort</a>. For example you can use a simple resize filter such as:</p> 2920 2921<pre class="text"> 2922 Point Hermite Cubic 2923 Box Gaussian Catrom 2924 Triangle Quadratic Mitchell 2925</pre> 2926 2927<p>The <kbd>Bessel</kbd> and <kbd>Sinc</kbd> filter is also provided (as well 2928as a faster <kbd>SincFast</kbd> equivalent form). However these filters are 2929generally useless on their own as they are infinite filters that are being 2930clipped to the filters support size. Their direct use is not recommended 2931except via expert settings (see below). </p> 2932 2933<p>Instead these special filter functions are typically windowed by a windowing 2934function that the <a href="#filter" >-filter</a> setting defines. That is 2935using these functions will define a 'Windowed' filter, appropriate to the 2936operator involved. Windowed filters include: </p> 2937 2938<pre class="text"> 2939 Lanczos Hamming Parzen 2940 Blackman Kaiser Welsh 2941 Hanning Bartlett Bohman 2942</pre> 2943 2944<p>Also one special self-windowing filter is also provided 2945<kbd>Lagrange</kbd>, which will automagically re-adjust its function depending 2946on the current 'support' or 'lobes' expert settings (see below).</p> 2947 2948<p>If you do not select a filter with this option, the filter defaults to 2949<kbd>Mitchell</kbd> for a colormapped image, a image with a matte channel, or 2950if the image is enlarged. Otherwise the filter default to 2951<kbd>Lanczos</kbd>.</p> 2952 2953<p>To print a complete list of resize filters, use the <a href="#list">-list 2954filter</a> option.</p> 2955 2956<p>You can modify how the filter behaves as it scales your image through the 2957use of these expert settings (see also <a href="#define" >-define</a> and <a 2958href="#set" >-set</a>):-</p> 2959 2960<dl class="doc"> 2961<dt>-define filter:blur=<em>factor</em></dt> 2962<dd>Scale the X axis of the filter (and its window). Use > 1.0 for 2963 blurry or < 1.0 for sharp. This should only be used with Gaussian and 2964 Gaussian-like filters simple filters, or you may not get the expected 2965 results. </dd> 2966 2967<dt>-define filter:support=<em>radius</em></dt> 2968<dd>Set the filter support radius. Defines how large the filter should be and 2969 thus directly defines how slow the filtered resampling process is. All 2970 filters have a default 'prefered' support size. Some filters like 2971 <kbd>Lagrange</kbd> and windowed filters adjust themselves depending on 2972 this value. With simple filters this value either does nothing (but slow 2973 the resampling), or will clip the filter function in a detrimental way. 2974 </dd> 2975 2976<dt>-define filter:lobes=<em>count</em></dt> 2977<dd>Set the number of lobes to use for the Sinc/Bessel filter. This an 2978 alternative way of specifying the 'support' range of the filter, that is 2979 designed to be more suited to windowed filters, especially when used for 2980 image distorts.</dd> 2981 2982<dt>-define filter:b=<em>b-spline_factor</em></dt> 2983<dt>-define filter:c=<em>keys_alpha_factor</em></dt> 2984<dd>Redefine the values used for cubic filters such as <kbd>Cubic</kbd>, 2985 <kbd>Catrom</kbd>, <kbd>Mitchel</kbd>, and <kbd>Hermite</kbd>, as well as 2986 the <kbd>Parzen</kbd> Sinc windowing function. If only one of the values 2987 are defined, the other is set so as to generate a 'Keys' type cubic 2988 filter. Values meaning was defined by a research paper by 2989 Mitchell-Netravali.</dd> 2990 2991<dt>-define filter:filter=<em>filter_function</em></dt> 2992<dd>Use this function directly as the scaling filter. This will allow 2993 you to directly use a windowing filter such as <kbd>Blackman</kbd>, 2994 rather than as its normal usage as a windowing function for 'Sinc' or 2995 'Bessel' functions. If defined, no windowing function is used, unless the 2996 following expert setting is also defined.</dd> 2997 2998<dt>-define filter:window=<em>filter_function</em></dt> 2999<dd>The IIR (infinite impulse response) filters <kbd>Bessel</kbd> and 3000 <kbd>Sinc</kbd> are windowed (brought down to zero over the defined 3001 support range) with the given filter. This allows you to specify a filter 3002 function that is not normally used as a windowing function, such as 3003 <kbd>Box</kbd>, (which effectively turns off the windowing function), 3004 to window a <kbd>Sinc</kbd>, or the function the previous setting defined. 3005 </dd> 3006 3007<dt>-define filter:verbose=<em>1</em></dt> 3008<dd>This causes IM to print information on the final internal filter 3009 selection to standard output. This includes a commented header on the 3010 filter settings being used, and data allowing the filter weights to be 3011 easily graphed. </dd> 3012 3013<dd>Note however that some filters are internally defined in terms of other 3014 filters. The <kbd>Lanczos</kbd> filter for example is defined in terms of 3015 a <kbd>SincFast</kbd> windowed <kbd>SincFast</kbd> filter, while 3016 <kbd>Mitchell</kbd> is defined as a <kbd>Cubic</kbd> filter with specific 3017 'B' and 'C' settings. </dd> 3018 3019</dl> 3020 3021<p>For example, to get a 8 lobe Bessel windowed Bessel filter:</p> 3022 3023<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -filter bessel \ <br/> 3024 -set filter:window=bessel -set filter:lobes=8 \ <br/> 3025 -resize 150% image.jpg</span></p> 3026<p>Or a raw un-windowed Sinc filter with 4 lobes:</p> 3027 3028<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -set filter:filter=sinc -set filter:lobes=4 \ <br/> 3029 -resize 150% image.jpg</span></p> 3030<p>Note that the use of expert options (except for 'blur' with simple resize 3031filters, and 'verbose' for viewing the internal filter selection), are 3032provided for image processing experts who have studied and understood how 3033resize filters work. Without this knowledge, and an understanding of the 3034definition of the actual filters involved, using expert settings are more 3035likely to be detrimental to your image resizing.</p> 3036 3037 3038<div style="margin: auto;"> 3039 <h4><a id="flatten"></a>-flatten</h4> 3040</div> 3041 3042<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>This is a simple alias for the <a href="#layers" >-layers</a> method "flatten".</td><td style='text-align:right;'></td></tr></table> 3043 3044 3045<div style="margin: auto;"> 3046 <h4><a id="flip"></a>-flip</h4> 3047</div> 3048 3049<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>create a <em>mirror image</em>.</td><td style='text-align:right;'></td></tr></table> 3050 3051<p>reflect the scanlines in the vertical direction.</p> 3052 3053<div style="margin: auto;"> 3054 <h4><a id="floodfill"></a>-floodfill {<em class="arg">+-</em>}<em class="arg">x</em>{<em class="arg">+-</em>}<em class="arg">y</em> <em class="arg">color</em></h4> 3055</div> 3056 3057<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>floodfill the image with color at the specified offset. Using <a href="#fuzz" >-fuzz</a> to floodfill pixels which only change by a small amount.</td><td style='text-align:right;'></td></tr></table> 3058 3059<div style="margin: auto;"> 3060 <h4><a id="flop"></a>-flop</h4> 3061</div> 3062 3063<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>create a <em>mirror image</em>.</td><td style='text-align:right;'></td></tr></table> 3064 3065<p>reflect the scanlines in the horizontal direction.</p> 3066 3067 3068<div style="margin: auto;"> 3069 <h4><a id="font"></a>-font <em class="arg">name</em></h4> 3070</div> 3071 3072<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>set the font to use when annotating images with text, or creating labels.</td><td style='text-align:right;'></td></tr></table> 3073 3074<p>To print a complete list of fonts, use the <a href="#list">-list font</a> option (for versions prior to 6.3.6, use 'type' instead of 'font').</p> 3075 3076<p>In addition to the fonts specified by the above pre-defined list, you can 3077also specify a font from a specific source. For example <kbd>Arial.ttf</kbd> 3078is a TrueType font file, <kbd>ps:helvetica</kbd> is PostScript font, and 3079<kbd>x:fixed</kbd> is X11 font.</p> 3080 3081<p>For other settings that affect fonts, see the options <a href="#family">-family</a>, <a href="#stretch">-stretch</a>, <a href="#style">-style</a>, and <a href="#weight">-weight</a>. </p> 3082 3083 3084<div style="margin: auto;"> 3085 <h4><a id="foreground"></a>-foreground <em class="arg">color</em></h4> 3086</div> 3087 3088<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Define the foreground color.</td><td style='text-align:right;'></td></tr></table> 3089 3090<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 3091 3092<p>The default foreground color is black.</p> 3093 3094<div style="margin: auto;"> 3095 <h4><a id="format"></a>-format <em class="arg">type</em></h4> 3096</div> 3097 3098<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the image format type.</td><td style='text-align:right;'></td></tr></table> 3099 3100<p>When used with the <kbd>mogrify</kbd> utility, this option converts any image to the image <a href="/www/formats.html">format</a> you specify. For a list of image format types supported by ImageMagick, use <a href="#list">-list format</a>.</p> 3101 3102<p>By default the file is written to its original name. However, if the filename extension matches a supported format, the extension is replaced with the image format type specified with <a href="#format">-format</a>. For example, if you specify <em class="arg">tiff</em> as the format type and the input image filename is <em class="arg">image.gif</em>, the output image filename becomes <em class="arg">image.tiff</em>.</p> 3103 3104<div style="margin: auto;"> 3105 <h4><a id="format_identify_"></a>-format <em class="arg">string</em></h4> 3106</div> 3107 3108<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>output formatted image characteristics.</td><td style='text-align:right;'>[<a href="/www/identify.html">identify</a>]</td></tr></table> 3109 3110<p>See <a href="/www/escape.html">Format and Print Image Properties</a> for an explanation on how to specify the argument to this option.</p> 3111 3112<div style="margin: auto;"> 3113 <h4><a id="frame"></a>-frame <em class="arg">geometry</em></h4> 3114</div> 3115 3116<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Surround the image with a border or beveled frame.</td><td style='text-align:right;'></td></tr></table> 3117 3118<p>The color of the border is specified with the <a href="#mattecolor" 3119>-mattecolor</a> command line option. </p> 3120 3121<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. The <em class="arg">size</em> portion of the <em 3122class="arg">geometry</em> argument indicates the amount of extra width and 3123height that is added to the dimensions of the image. If no offsets are given 3124in the <em class="arg">geometry</em> argument, then the border added is 3125a solid color. Offsets <em>x</em> and <em>y</em>, if present, specify that 3126the width and height of the border is partitioned to form an outer bevel of 3127thickness <em>x</em> pixels and an inner bevel of thickness 3128<em>y</em> pixels. Negative offsets make no sense as frame arguments. 3129</p> 3130 3131<p>The <a href="#frame">-frame</a> option is affected by the current <a 3132href="#compose">-compose</a> setting and assumes that this is using the default 3133'<kbd>Over</kbd>' composition method. It generates a image of the appropriate 3134size with the current <a href="#bordercolor">-bordercolor</a> setting, and then 3135draws the frame of four distinct colors close to the current <a 3136href="#mattecolor">-mattecolor</a>. The original image is then overlaid onto 3137center of this image. This means that with the default compose method of 3138'<kbd>Over</kbd>' any transparent parts may be replaced by the current <a 3139href="#bordercolor">-bordercolor</a> setting.</p> 3140 3141<p>The image composition is not 3142affected by the <a href="#gravity">-gravity</a> option.</p> 3143 3144 3145<div style="margin: auto;"> 3146 <h4><a id="frame_import_"></a>-frame</h4> 3147</div> 3148 3149<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>include the X window frame in the imported image.</td><td style='text-align:right;'>[<a href="/www/import.html">import</a>]</td></tr></table> 3150 3151<div style="margin: auto;"> 3152 <h4><a id="function"></a>-function <em class="arg">function</em> <em class="arg">parameters</em></h4> 3153</div> 3154 3155<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Apply a function to channel values.</td><td style='text-align:right;'></td></tr></table> 3156 3157<p>This operator performs calculations based on the given arguments to modify each of the color values for each previously set <a href="#channel">-channel</a> in the image. See <a href="#evaluate">-evaluate</a> for details concerning how the results of the calculations are handled.</p> 3158 3159<p>This is can be considered a multi-argument version of the <a href="#evaluate">-evaluate</a> operator. (Added in ImageMagick 6.4.8−8.)</p> 3160 3161<p>Here, <em class="arg">parameters</em> is a comma-separated list of numerical values. The number of values varies depending on which <em class="arg">function</em> is selected. Choose the <em class="arg">function</em> from:</p> 3162 3163<pre class="text"> 3164 Polynomial 3165 Sinusoid 3166 Arcsin 3167 Arctan 3168</pre> 3169 3170<p>To print a complete list of <a href="#function">-function</a> operators, use <a href="#list">-list function</a>. Descriptions follow.</p> 3171 3172<dl class="doc"> 3173<dt><kbd>Polynomial</kbd></dt> 3174<dd> 3175<p>The <kbd>Polynomial</kbd> function takes an arbitrary number of parameters, these being the coefficients of a polynomial, in decreasing order of degree. That is, entering</p> 3176 3177<div style="text-align: center"> 3178 -function Polynomial <em>a</em><sub><em>n</em></sub>,<em>a</em><sub><em>n</em>-1</sub>,...<em>a</em><sub>1</sub>,<em>a</em><sub>0</sub> 3179</div> 3180 3181<p>will invoke a polynomial function given by</p> 3182 3183<div style="text-align: center"> 3184 <em>a</em><sub><em>n</em></sub> <b><em>u</em></b><sup><em>n</em></sup> + 3185 <em>a</em><sub><em>n</em>-1</sub> <b><em>u</em></b><sup><em>n</em>-1</sup> + 3186 ··· <em>a</em><sub>1</sub> <b><em>u</em></b> + <em>a</em><sub>0</sub>, 3187</div> 3188 3189<p>where <b><em>u</em></b> is pixel's original normalized channel value.</p> 3190 3191<p>The <kbd>Polynomial</kbd> function can be used in place of <kbd>Set</kbd> (the <em>constant</em> polynomial) and <kbd>Add</kbd>, <kbd>Divide</kbd>, <kbd>Multiply</kbd>, and <kbd>Subtract</kbd> (some <em>linear</em> polynomials) of the <a href="#evaluate">-evaluate</a> operator. The <a href="#level">-level</a> operator also affects channels linearly. Some correspondences follow.</p> 3192 3193<table class="doc"> 3194 <col width="35%" /> 3195 <col width="35%" /> 3196 <col width="30%" /> 3197 <tr> 3198 <td>-evaluate Set <em class="arg">value</em> </td> 3199 <td>-function Polynomial <em class="arg">value</em></td> 3200 <td>(Constant functions; set <em class="arg">value</em>×100% gray when channels are RGB.)</td> 3201 </tr> 3202 <tr> 3203 <td>-evaluate Add <em class="arg">value</em> </td> 3204 <td>-function Polynomial 1,<em class="arg">value</em></td> 3205 </tr> 3206 <tr> 3207 <td>-evaluate Subtract <em class="arg">value</em> </td> 3208 <td>-function Polynomial 1,−<em class="arg">value</em></td> 3209 </tr> 3210 <tr> 3211 <td>-evaluate Multiply <em class="arg">value</em> </td> 3212 <td>-function Polynomial <em class="arg">value</em>,0</td> 3213 </tr> 3214 <tr> 3215 <td>+level black% x white%</td> 3216 <td>-function Polynomial A,B</td> 3217 <td>(Reduce contrast. Here, A=(white-black)/100 and B=black/100.)</td> 3218 </tr> 3219</table> 3220 3221<p>The <kbd>Polynomial</kbd> function gives great versatility, since polynomials can be used to fit any continuous curve to any degree of accuracy desired.</p> 3222</dd> 3223 3224<dt><kbd>Sinusoid</kbd></dt> 3225<dd> 3226<p>The <kbd>Sinusoid</kbd> function can be used to vary the channel values sinusoidally by setting frequency, phase shift, amplitude, and a bias. These values are given as one to four parameters, as follows,</p> 3227 3228<div style="text-align: center"> 3229 -function <kbd>Sinusoid</kbd> <em class="arg">freq</em>,[<em class="arg">phase</em>,[<em class="arg">amp</em>,[<em class="arg">bias</em>]]] 3230</div> 3231 3232<p>where <em>phase</em> is in degrees. (The domain [0,1] of the function corresponds to 0 through <em class="arg">freq</em>×360 degrees.) The result is that if a pixel's normalized channel value is originally <b><em>u</em></b>, its resulting normalized value is given by </p> 3233 3234<div style="text-align: center"> 3235<em class="arg">amp</em> * sin(2*π* (<em class="arg">freq</em> * <b><em>u</em></b> + <em class="arg">phase</em> / 360)) + <em class="arg">bias</em> 3236</div> 3237 3238<p> For example, the following generates a curve that starts and ends at 0.9 (when <b><em>u</em></b>=0 and 1, resp.), oscillating three times between .7−.2=.5 and .7+.2=.9. </p> 3239 3240<p class="crtsnip"> 3241 -function Sinusoid 3,-90,.2,.7 3242</p> 3243 3244<p>The default values of <em class="arg">amp</em> and <em class="arg">bias</em> are both .5. The default for <em class="arg">phase</em> is 0.</p> 3245 3246<p>The <kbd>Sinusoid</kbd> function generalizes <kbd>Sin</kbd> and <kbd>Cos</kbd> of the <a href="#evaluate">-evaluate</a> operator by allowing varying amplitude, phase and bias. The correspondence is as follows.</p> 3247 3248<table class="doc"> 3249 <tr> 3250 <td>-evaluate Sin <em class="arg">freq</em> </td> 3251 <td>-function Sinusoid <em class="arg">freq</em>,0 </td> 3252 </tr> 3253 <tr> 3254 <td>-evaluate Cos <em class="arg">freq</em> </td> 3255 <td>-function Sinusoid <em class="arg">freq</em>,90 </td> 3256 </tr> 3257</table> 3258</dd> 3259 3260<dt><kbd>ArcSin</kbd></dt> 3261<dd> 3262<p>The <kbd>ArcSin</kbd> function generates the inverse curve of a Sinusoid, 3263and can be used to generate cylindrical distortion and displacement maps. 3264The curve can be adjusted relative to both the input values and output range 3265of values.</p> 3266 3267<p style="text-align: center"> 3268 -function <kbd>ArcSin</kbd> <em class="arg">width</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]] 3269</p> 3270 3271<p>with all values given in terms of noramlize color values (0.0 for black, 32721.0 for white). Defaulting to values covering the full range from 0.0 to 1.0 3273for bout input (<em class="arg">width</em>), and output (<em 3274class="arg">width</em>) values. '<code>1.0,0.5,1.0,0.5</code>' </p> 3275 3276<p style="text-align: center"> 3277<em class="arg">range</em>/π * asin( 2/<em class="arg">width</em> * ( <b><em>u</em></b> - <em class="arg">center</em> ) ) + <em class="arg">bias</em> 3278</p> 3279 3280</dd> 3281 3282<dt><kbd>ArcTan</kbd></dt> 3283<dd> 3284<p>The <kbd>ArcTan</kbd> function generates a curve that smooth crosses from 3285limit values at infinities, though a center using the given slope value. 3286All these values can be adjusted via the arguments.</p> 3287 3288<p style="text-align: center"> 3289 -function <kbd>ArcTan</kbd> <em class="arg">slope</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]] 3290</p> 3291 3292<p>Defaulting to '<code>1.0,0.5,1.0,0.5</code>'. 3293</p> 3294 3295<p style="text-align: center"> 3296<em class="arg">range</em>/π * atan( <em class="arg">slope</em>*π * ( <b><em>u</em></b> - <em class="arg">center</em> ) ) + <em class="arg">bias</em> 3297</p> 3298 3299</dd> 3300 3301</dl> 3302 3303 3304<div style="margin: auto;"> 3305 <h4><a id="fuzz"></a>-fuzz <em class="arg">distance</em>{<em class="arg">%</em>}</h4> 3306</div> 3307 3308<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Colors within this <em class="arg">distance</em> are considered equal.</td><td style='text-align:right;'></td></tr></table> 3309 3310<p>A number of algorithms search for a target color. By default the color must be exact. Use this option to match colors that are close to the target color in RGB space. For example, if you want to automagically trim the edges of an image with <a href="#trim">-trim</a> but the image was scanned and the target background color may differ by a small amount. This option can account for these differences.</p> 3311 3312<p>The <em class="arg">distance</em> can be in absolute intensity units or, by appending <kbd>%</kbd> as a percentage of the maximum possible intensity (255, 65535, or 4294967295).</p> 3313 3314 3315<div style="margin: auto;"> 3316 <h4><a id="fx"></a>-fx <em class="arg">expression</em></h4> 3317</div> 3318 3319<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>apply a mathematical expression to an image or image channels.</td><td style='text-align:right;'></td></tr></table> 3320 3321<p>If the first character of <em class="arg">expression</em> is <kbd>@</kbd>, the expression is read from a file titled by the remaining characters in the string.</p> 3322 3323<p>See <a href="/www/fx.html">FX, The Special Effects Image Operator</a> for a detailed discussion of this option.</p> 3324 3325 3326<div style="margin: auto;"> 3327 <h4><a id="gamma"></a>-gamma <em class="arg">value</em></h4> 3328</div> 3329 3330<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>level of gamma correction.</td><td style='text-align:right;'></td></tr></table> 3331 3332<p>The same color image displayed on two different workstations may look different due to differences in the display monitor. Use gamma correction to adjust for this color difference. Reasonable values extend from <kbd>0.8</kbd> to <kbd>2.3</kbd>. Gamma less than 1.0 darkens the image and gamma greater than 1.0 lightens it. Large adjustments to image gamma may result in the loss of some image information if the pixel quantum size is only eight bits (quantum range 0 to 255).</p> 3333 3334<p>Gamma adjusts the image's channel values pixel-by-pixel according to a power law, namely, pow(pixel,1/gamma) or pixel^(1/gamma), where pixel is the normalized or 0 to 1 color value. For example, using a value of gamma=2 is the same as taking the square root of the image.</p> 3335 3336<p>You can apply separate gamma values to the red, green, and blue channels of the image with a gamma value list delimited with commas (e.g., <kbd>1.7,2.3,1.2</kbd>).</p> 3337 3338<p>Use <a href="#gamma">+gamma <em class="arg">value</em></a> to set the image gamma level without actually adjusting the image pixels. This option is useful if the image is of a known gamma but not set as an image attribute (e.g. PNG images).</p> 3339 3340<p>Note that gamma adjustments are also available via the <a href="#level">-level</a> operator.</p> 3341 3342<div style="margin: auto;"> 3343 <h4><a id="gaussian-blur"></a>-gaussian-blur <em class="arg">radius</em><br />-gaussian-blur <em class="arg">radius</em>x<em class="arg">sigma</em></h4> 3344</div> 3345 3346<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Blur the image with a Gaussian operator.</td><td style='text-align:right;'></td></tr></table> 3347 3348<p>Convolve the image with a Gaussian or normal distribution using the given 3349<em class="arg" >Sigma</em> value. The formula is:</p> 3350 3351<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="/images/gaussian-blur.png"/> 3352</div> 3353 3354<p>The <em class="arg" >Sigma</em> value is the important argument, and 3355determines the actual amount of blurring that will take place. </p> 3356 3357<p>The <em class="arg" >Radius</em> is only used to determine the size of the 3358array which will hold the calculated Gaussian distribution. It should be an 3359integer. If not given, or set to zero, IM will calculate the largest possible 3360radius that will provide meaningful results for the Gaussian distribution. 3361</p> 3362 3363<p>The larger the <em class="arg" >Radius</em> the radius the slower the 3364operation is. However too small a <em class="arg" >Radius</em>, and sever 3365aliasing effects may result. As a guideline, <em class="arg" >Radius</em> 3366should be at least twice the <em class="arg" >Sigma</em> value, though three 3367times will produce a more accurite result. </p> 3368 3369<p>This differs from the faster <a href="#blur">-blur</a> operator in that a 3370full 2-dimensional convolution is used to generate the weighted average of the 3371neighboring pixels. </p> 3372 3373<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 3374pixels which are outside the image proper are blurred into the final result. 3375</p> 3376 3377 3378<div style="margin: auto;"> 3379 <h4><a id="geometry"></a>-geometry <em class="arg">geometry</em></h4> 3380</div> 3381 3382<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the preferred size and location of the image.</td><td style='text-align:right;'></td></tr></table> 3383 3384<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 3385 3386<div style="margin: auto;"> 3387 <h4><a id="gravity"></a>-gravity <em class="arg">type</em></h4> 3388</div> 3389 3390<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Sets the current gravity suggestion for various other settings and options.</td><td style='text-align:right;'></td></tr></table> 3391 3392<p>Choices include: <kbd>NorthWest</kbd>, <kbd>North</kbd>, <kbd>NorthEast</kbd>, 3393<kbd>West</kbd>, <kbd>Center</kbd>, <kbd>East</kbd>, <kbd>SouthWest</kbd>, 3394<kbd>South</kbd>, <kbd>SouthEast</kbd>. Use <a href="#list">-list gravity</a> to get a complete 3395list of <a href="#gravity">-gravity</a> settings available in your ImageMagick 3396installation.</p> 3397 3398<p>The direction you choose specifies where to position text or subimages. For example, a gravity of <kbd>Center</kbd> forces the text to be centered within the image. By default, the image gravity is <kbd>NorthWest</kbd>. See <a href="#draw">-draw</a> for more details about graphic primitives. Only the text primitive of <a href="#draw">-draw</a> affected by the <a href="#gravity">-gravity</a> option.</p> 3399 3400<p>The <a href="#gravity">-gravity</a> option is also used in concert with the <a href="#geometry">-geometry</a> setting and other settings or options that take <em class="arg">geometry</em> as an argument, such as the <a href="#crop">-crop</a> option. </p> 3401 3402<p>If a <a href="#gravity">-gravity</a> setting occurs before another option or setting having a <em class="arg">geometry</em> argument that specifies an offset, the offset is usually applied to the point within the image suggested by the <a href="#gravity">-gravity</a> argument. Thus, in the following command, for example, suppose the file <kbd>image.png</kbd> has dimensions 200x100. The offset specified by the argument to <a href="#region">-region</a> is (−40,+20). The argument to <a href="#gravity">-gravity</a> is <kbd>Center</kbd>, which suggests the midpoint of the image, at the point (100,50). The offset (−40,20) is applied to that point, giving (100−40,50+20)=(60,70), so the specified 10x10 region is located at that point. (In addition, the <a href="#gravity">-gravity</a> affects the region itself, which is <em>centered</em> at the pixel coordinate (60,70). (See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.)</p> 3403 3404<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -gravity Center -region 10x10-40+20 \ <br/> -negate output.png</span></p> 3405<p>When used as an option to <a href="/www/composite.html">composite</a>, <a href="#gravity">-gravity</a> gives the direction that the image gravitates within the composite.</p> 3406 3407<p>When used as an option to <a href="/www/montage.html">montage</a>, <a href="#gravity">-gravity</a> gives the direction that an image gravitates within a tile. The default gravity is <kbd>Center</kbd> for this purpose.</p> 3408 3409 3410<div style="margin: auto;"> 3411 <h4><a id="green-primary"></a>-green-primary <em class="arg">x,y</em></h4> 3412</div> 3413 3414<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>green chromaticity primary point.</td><td style='text-align:right;'></td></tr></table> 3415 3416 3417<div style="margin: auto;"> 3418 <h4><a id="hald-clut"></a>-hald-clut</h4> 3419</div> 3420 3421<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>apply a Hald color lookup table to the image.</td><td style='text-align:right;'></td></tr></table> 3422 3423<p>A Hald color lookup table is a 3-dimensional color cube mapped to 2 3424dimensions. Create it with the <kbd>HALD:</kbd> prefix (e.g. HALD:8). You 3425can apply any color transformation to the Hald image and then use this option 3426to apply the transform to the image. </p> 3427 3428<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png hald.png -hald-clut transform.png</span></p> 3429<p>This option provides a convenient method for you to use Gimp or Photoshop 3430to make color corrections to the Hald CLUT image and subsequently apply them 3431to multiple images using an ImageMagick script. </p> 3432 3433<p>Note that the representation is only of the normal RGB color space and that 3434the whole color value triplet is used for the interpolated lookup of the 3435represented Hald color cube image. Because of this the operation is not <a 3436href="#channel" >-channel</a> setting effected, nor can it adjust or modify an 3437images transparency or alpha/matte channel.</p> 3438 3439<p>See also <a href="#clut" >-clut</a> which provides color value replacement 3440of the individual color channels, usally involving a simplier gray-scale 3441image. E.g: gray-scale to color replacement, or modification by a histogram 3442mapping. </p> 3443 3444 3445<div style="margin: auto;"> 3446 <h4><a id="help"></a>-help</h4> 3447</div> 3448 3449<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>print usage instructions.</td><td style='text-align:right;'></td></tr></table> 3450 3451<div style="margin: auto;"> 3452 <h4><a id="highlight-color"></a>-highlight-color <em class="arg">color</em></h4> 3453</div> 3454 3455<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>when comparing images, emphasize pixel differences with this color.</td><td style='text-align:right;'></td></tr></table> 3456 3457<div style="margin: auto;"> 3458 <h4><a id="iconGeometry"></a>-iconGeometry <em class="arg">geometry</em></h4> 3459</div> 3460 3461<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>specify the icon geometry.</td><td style='text-align:right;'></td></tr></table> 3462 3463<p>Offsets, if present in the geometry specification, are handled in the same manner as the <a href="#geometry">-geometry</a> option, using X11 style to handle negative offsets.</p> 3464 3465<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 3466 3467<div style="margin: auto;"> 3468 <h4><a id="iconic"></a>-iconic</h4> 3469</div> 3470 3471<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>iconic animation.</td><td style='text-align:right;'></td></tr></table> 3472 3473<div style="margin: auto;"> 3474 <h4><a id="identify"></a>-identify</h4> 3475</div> 3476 3477<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>identify the format and characteristics of the image.</td><td style='text-align:right;'></td></tr></table> 3478 3479<p>This information is printed: image scene number; image name; image size; the image class (<em class="arg">DirectClass</em> or <em class="arg">PseudoClass</em>); the total number of unique colors; and the number of seconds to read and transform the image. Refer to <a href="/www/miff.html">MIFF</a> for a description of the image class.</p> 3480 3481<p>If <a href="#colors">-colors</a> is also specified, the total unique colors in the image and color reduction error values are printed. Refer to <a href="/www/quantize.html">color reduction algorithm</a> for a description of these values.</p> 3482 3483<p>If <a href="#verbose">-verbose</a> precedes this option, copious 3484amounts of image properties are displayed including image statistics, profiles, 3485image histogram, and others.</p> 3486 3487<div style="margin: auto;"> 3488 <h4><a id="ift"></a>-ift</h4> 3489</div> 3490 3491<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>implements the inverse discrete Fourier transform (DFT).</td><td style='text-align:right;'></td></tr></table> 3492 3493<p>This option is new as of ImageMagick 6.5.4-3 (and now working for Windows users in ImageMagick 6.6.0-9). It transforms a pair of magnitude and phase images from the frequency domain to a single image in the normal or spatial domain. See for example, <a href="http://en.wikipedia.org/wiki/Fourier_transform">Fourier Transform</a>, <a href="http://en.wikipedia.org/wiki/DFT">Discrete Fourier Transform</a> and <a href="http://en.wikipedia.org/wiki/FFT">Fast Fourier Transform</a>.</p> 3494 3495<p>For example, depending upon the image format used to store the result of the <a href="#fft">-fft</a>, one would use either</p> 3496 3497<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert fft_image.miff -ift fft_image_ift.png</span></p> 3498<p>or</p> 3499 3500<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert fft_image-0.png fft_image-1.png -ift fft_image_ift.png</span></p> 3501 3502<p>The resulting image may need to be cropped due to padding introduced when the original image, prior to the <a href="#fft">-fft</a> or <a href="#fft">+fft</a>, was not square or even dimensioned. Any padding is at the right and/or bottom sides of the image.</p> 3503 3504<p>The <a href="http://www.fftw.org/">FFTW</a> delegate library is required to use <a href="#ift">-ift</a>.</p> 3505 3506<p>Use <a href="#ift">+ift</a> (with HDRI enabled) to transform a pair of real and imaginary images from the frequency domain to a single image in the normal (spatial) domain.</p> 3507 3508<div style="margin: auto;"> 3509 <h4><a id="immutable"></a>-immutable</h4> 3510</div> 3511 3512<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>make image immutable.</td><td style='text-align:right;'></td></tr></table> 3513 3514<div style="margin: auto;"> 3515 <h4><a id="implode"></a>-implode <em class="arg">factor</em></h4> 3516</div> 3517 3518<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>implode image pixels about the center.</td><td style='text-align:right;'></td></tr></table> 3519 3520<div style="margin: auto;"> 3521 <h4><a id="insert"></a>-insert <em class="arg">index</em></h4> 3522</div> 3523 3524<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>insert the last image into the image sequence.</td><td style='text-align:right;'></td></tr></table> 3525 3526<p>This option takes last image in the current image sequence and inserts it at the given index. If a negative index is used, the insert position is calculated before the last image is removed from the sequence. As such <kbd>-insert -1</kbd> will result in no change to the image sequence.</p> 3527 3528<p>The <kbd>+insert</kbd> option is equivalent to <kbd>-insert -1</kbd>. In other words, insert the last image, at the end of the current image sequence. Consequently this has no effect on the image sequence order.</p> 3529 3530<div style="margin: auto;"> 3531 <h4><a id="intent"></a>-intent <em class="arg">type</em></h4> 3532</div> 3533 3534<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>use this type of rendering intent when managing the image color.</td><td style='text-align:right;'></td></tr></table> 3535 3536<p>Use this option to affect the color management operation of an image (see <a href="#profile">-profile</a>). Choose from these intents: <kbd>Absolute, Perceptual, Relative, Saturation</kbd>.</p> 3537 3538<p>The default intent is undefined.</p> 3539 3540<p>To print a complete list of rendering intents, use <a href="#list">-list intent</a>.</p> 3541 3542<div style="margin: auto;"> 3543 <h4><a id="interlace"></a>-interlace <em class="arg">type</em></h4> 3544</div> 3545 3546<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the type of interlacing scheme.</td><td style='text-align:right;'></td></tr></table> 3547 3548<p>Choose from:</p> 3549 3550<pre class="text"> 3551 none 3552 line 3553 plane 3554 partition 3555 JPEG 3556 GIF 3557 PNG 3558</pre> 3559 3560<p>This option is used to specify the type of interlacing scheme for raw image formats such as <kbd>RGB</kbd> or <kbd>YUV</kbd>.</p> 3561 3562<p><kbd>None</kbd> means do not interlace (RGBRGBRGBRGBRGBRGB...),</p> 3563 3564<p><kbd>Line</kbd> uses scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...), and.</p> 3565 3566<p><kbd>Plane</kbd> uses plane interlacing (RRRRRR...GGGGGG...BBBBBB...).</p> 3567 3568<p><kbd>Partition</kbd> is like plane except the different planes are saved to individual files (e.g. image.R, 3569image.G, and image.B).</p> 3570 3571<p>Use <kbd>Line</kbd> or <kbd>Plane</kbd> to create an <kbd>interlaced PNG</kbd> or <kbd>GIF</kbd> or <kbd>progressive JPEG</kbd> 3572image.</p> 3573 3574<p>To print a complete list of interlacing schemes, use <a href="#list">-list interlace</a>.</p> 3575 3576<div style="margin: auto;"> 3577 <h4><a id="interpolate"></a>-interpolate <em class="arg">type</em></h4> 3578</div> 3579 3580<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the pixel color interpolation method to use when looking up a color based on a floating point or real value.</td><td style='text-align:right;'></td></tr></table> 3581 3582<p>When looking up the color of a pixel using a non-integer floating point 3583value, you typically fall in between the pixel colors defined by the source 3584image. This setting determines how the color is determined from the colors of 3585the pixels surrounding that point. That is how to determine the color of a 3586point that falls between two, or even four different colored pixels. </p> 3587 3588<pre class="text"> 3589 integer: The color of the top-left pixel (floor function) 3590 nearest-neighbor: The nearest pixel to the lookup point (rounded function) 3591 average: The average color of the surrounding four pixels 3592 bilinear A double linear interpolation of pixels (the default) 3593 mesh Divide area into two flat triangular interpolations 3594 bicubic Fitted bicubic-spines of surrounding 16 pixels 3595 spline Direct spline curves (colors are blurred) 3596 filter Use resize <a href="#filter">-filter</a> settings 3597</pre> 3598 3599<p>This most important for distortion operators such as <a href="#distort" 3600>-distort</a>, <a href="#implode" >-implode</a>, <a href="#transform" 3601>-transform</a> and <a href="#fx" >-fx</a>. </p> 3602 3603<p>To print a complete list of interpolation methods, use <a href="#list">-list interpolate</a>.</p> 3604 3605<p>See also <a href="#virtual-pixel" >-virtual-pixel</a>, for control of the 3606lookup for positions outside the boundaries of the image. </p> 3607 3608 3609<div style="margin: auto;"> 3610 <h4><a id="interline-spacing"></a>-interline-spacing <em class="arg">value</em></h4> 3611</div> 3612 3613<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the space between two text lines.</td><td style='text-align:right;'></td></tr></table> 3614 3615<div style="margin: auto;"> 3616 <h4><a id="interword-spacing"></a>-interword-spacing <em class="arg">value</em></h4> 3617</div> 3618 3619<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the space between two words.</td><td style='text-align:right;'></td></tr></table> 3620 3621<div style="margin: auto;"> 3622 <h4><a id="kerning"></a>-kerning <em class="arg">value</em></h4> 3623</div> 3624 3625<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the space between two letters.</td><td style='text-align:right;'></td></tr></table> 3626 3627<div style="margin: auto;"> 3628 <h4><a id="label"></a>-label <em class="arg">name</em></h4> 3629</div> 3630 3631<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>assign a label to an image.</td><td style='text-align:right;'></td></tr></table> 3632 3633<p>Use this option to assign a specific label to the image, as it is read in 3634or created. You can use the <a href="#set" >-set</a> operation to re-assign 3635a the labels of images already read in. Image formats such as TIFF, PNG, 3636MIFF, supports saving the label information with the image.</p> 3637 3638<p>When saving an image to a <em class="arg">PostScript</em> file, any label 3639assigned to an image is used as a header string to print above the postscript 3640image. </p> 3641 3642<p>You can include the image filename, type, width, height, or other image 3643attribute by embedding special format character. See <a href="/www/escape.html">Format and Print Image 3644Properties</a> for details of the percent escape codes.</p> 3645 3646<p>For example,</p> 3647 3648<p class="crtsnip"> 3649 -label "%m:%f %wx%h" bird.miff 3650</p> 3651 3652<p>assigns an image label of <kbd>MIFF:bird.miff 512x480</kbd> to the 3653"<kbd>bird.miff</kbd>" image and whose width is 512 and height is 480, as it 3654is read in. If a <a href="#label">+label</a> option was used instead, any 3655existing label present in the image would be used. You can remove all labels 3656from an image by assigning the empty string. </p> 3657 3658<p>A label is not drawn on the image, but is embedded in the image datastream 3659via <em>Label</em> tag or similar mechanism. If you want the label to be 3660visible on the image itself, use the <a href="#draw">-draw</a> option, or 3661during the final processing in the creation of a image montage.</p> 3662 3663<p>If the first character of <em class="arg">string</em> is <em 3664class="arg">@</em>, the image label is read from a file titled by the 3665remaining characters in the string. Labels in a file are literal, no embedded 3666formatting characters are recognized.</p> 3667 3668 3669<div style="margin: auto;"> 3670 <h4><a id="lat"></a>-lat <em class="arg">width</em><br />-lat <em class="arg">width</em>x<em class="arg">height</em>{<em class="arg">+-</em>}<em class="arg">offset</em>{<em class="arg">%</em>}</h4> 3671</div> 3672 3673<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>perform local adaptive threshold.</td><td style='text-align:right;'></td></tr></table> 3674 3675<p>Adaptively threshold each pixel based on the value of pixels in a 3676surrounding window. If the current pixel is lighter than this average plus 3677the optional <kbd>offset</kbd>, then it is made white, otherwise it is made 3678black. Small variations in pixel values such as found in scanned documents 3679can be ignored if offset is positive. A negative offset will make it more 3680sensitive to those small variations. </p> 3681 3682<p>This is commonly used to threshold images with an uneven background. It is 3683based on the assumption that average color of the small window is the 3684the local background color, from which to separate the forground color. </p> 3685 3686 3687<div style="margin: auto;"> 3688 <h4><a id="layers"></a>-layers <em class="arg">method</em></h4> 3689</div> 3690 3691<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>handle multiple images forming a set of image layers or animation frames.</td><td style='text-align:right;'></td></tr></table> 3692 3693<p>Perform various image operation methods to a ordered sequence of images 3694which may represent either a set of overlaid 'image layers', a GIF disposal 3695animation, or a fully-'coalesced' animation sequence. </p> 3696 3697<table class="doc"> 3698 <tbody> 3699 <tr valign="top"> 3700 <th align="left" style="width: 8%">Method</th> 3701 <th align="left">Description</th> 3702 </tr> 3703 3704 <tr valign="top"> 3705 <td valign="top">compare-any</td> 3706 <td valign="top">Crop the second and later frames to the smallest rectangle 3707 that contains all the differences between the two images. No GIF <a 3708 href="#dispose" >-dispose</a> methods are taken into account. </td> 3709 </tr> 3710 3711 <tr><td></td><td>This exactly the same as the <a href="#deconstruct" 3712 >-deconstruct</a> operator, and does not preserve animations normal 3713 working, especially when animation used layer disposal methods such as 3714 '<kbd>Previous</kbd>' or '<kbd>Background</kbd>'. </td> 3715 </tr> 3716 3717 <tr valign="top"> 3718 <td valign="top">compare-clear</td> 3719 <td valign="top">As '<kbd>compare-any</kbd>' but crop to the bounds of any 3720 opaque pixels which become transparent in the second frame. That is the 3721 smallest image needed to mask or erase pixels for the next frame. </td> 3722 </tr> 3723 3724 <tr valign="top"> 3725 <td valign="top">compare-overlay</td> 3726 <td valign="top">As '<kbd>compare-any</kbd>' but crop to pixels that add 3727 extra color to the next image, as a result of overlaying color pixels. 3728 That is the smallest single overlaid image to add or change colors. </td> 3729 </tr> 3730 3731 <tr><td></td><td>This can be used with the <a href="#compose" >-compose</a> alpha 3732 composition method '<kbd>change-mask</kbd>', to reduce the image to 3733 just the pixels that need to be overlaid. </td> 3734 </tr> 3735 3736 <tr valign="top"> 3737 <td valign="top">coalesce</td> 3738 <td valign="top">Equivalent to a call to the <a href="#coalesce" 3739 >-coalesce</a> operator. Apply the layer disposal methods set in the 3740 current image sequence to form a fully defined animation sequence, as 3741 it should be displayed. Effectively converting a GIF animation into a 3742 'film strip'-like animation. </td> 3743 </tr> 3744 3745 <tr valign="top"> 3746 <td valign="top">composite</td> 3747 <td valign="top">Alpha Composition of two image lists, separated by a 3748 "<kbd>null:</kbd>" image, with the destination image list first, and 3749 the source images last. An image from each list are composited 3750 together until one list is finished. The separator image and source 3751 image lists are removed. </td> 3752 </tr> 3753 3754 3755 <tr><td></td> 3756 <td>The <a href="#geometry" >-geometry</a> offset is adjusted according 3757 to <a href="#gravity" >-gravity</a> in accordance of the virtual 3758 canvas size of the first image in each list. Unlike a normal <a 3759 href="#composite" >-composite</a> operation, the canvas offset is also 3760 added to the final composite positioning of each image. </td> </tr> 3761 3762 <tr><td></td> 3763 <td>If one of the image lists only contains one image, that image is 3764 applied to all the images in the other image list, regardless of which 3765 list it is. In this case it is the image meta-data of the list which 3766 preserved. </td> 3767 </tr> 3768 3769 3770 <tr valign="top"> 3771 <td valign="top">dispose</td> 3772 <td valign="top">This like '<kbd>coalesce</kbd>' but shows the look of 3773 the animation after the layer disposal method has been applied, before 3774 the next sub-frame image is overlaid. That is the 'dispose' image that 3775 results from the application of the GIF <a href="#dispose" 3776 >-dispose</a> method. This allows you to check what 3777 is going wrong with a particular animation you may be developing. 3778 </td> 3779 </tr> 3780 3781 <tr valign="top"> 3782 <td valign="top">flatten</td> 3783 <td valign="top">Create a canvas the size of the first images virtual 3784 canvas using the current <a href="#background" >-background</a> color, 3785 and <a href="#compose" >-compose</a> each image in turn onto that 3786 canvas. Images falling outside that canvas is clipped. Final 3787 image will have a zero virtual canvas offset. </td> 3788 </tr> 3789 3790 <tr><td></td> 3791 <td>This usally used as one of the final 'image layering' operations 3792 overlaying all the prepared image layers into a final image. </td> 3793 </tr> 3794 3795 <tr><td></td> 3796 <td>For a single image this method can also be used to fillout a virtual 3797 canvas with real pixels, or to underlay a opaque color to remove 3798 transparency from an image.</td> 3799 </tr> 3800 3801 3802 <tr valign="top"> 3803 <td valign="top">merge</td> 3804 <td valign="top">As 'flatten' method but merging all the given image 3805 layers into a new layer image just large enough to hold all the image 3806 without clipping or extra space. The new images virtual offset will 3807 prevere the position of the new layer, even if this offset is 3808 negative. the virtual canvas size of the first image is preserved. 3809 </td> 3810 </tr> 3811 3812 <tr><td></td><td>Caution is advised when handling image layers with negative offsets 3813 as few image file formats handle them correctly. </td> 3814 </tr> 3815 3816 <tr valign="top"> 3817 <td valign="top">mosaic</td> 3818 <td valign="top">As 'flatten' method but expanding the initial canvas size 3819 of the first image so as to hold all the image layers. However as a 3820 virtual canvas is 'locked' to the origin, by definition, image layers 3821 with a negative offsets will still be clipped by the top and left 3822 edges.</td> 3823 </tr> 3824 3825 <tr><td></td><td>This method is commonly used to layout individual image using various 3826 offset but without knowing the final canvas size. The resulting image 3827 will, like 'flatten' not have any virtual offset, so can be saved to 3828 any image file format. </td> 3829 </tr> 3830 3831 3832 <tr valign="top"> 3833 <td valign="top">optimize</td> 3834 <td valign="top">Optimize a coalesced animation, into GIF animation using 3835 a number of general techniques. This currently a short cut to 3836 apply both the '<kbd>optimize-frame</kbd>', and 3837 '<kbd>optimize-transparency</kbd>' methods but may be expanded to 3838 include other optimization methods as they are developed. </td> 3839 </tr> 3840 3841 <tr valign="top"> 3842 <td valign="top">optimize-frame</td> 3843 <td valign="top">Optimize a coalesced animation, into GIF animation by 3844 reducing the number of pixels per frame as much as possible by 3845 attempting to pick the best layer disposal method to use, while ensuring 3846 the result will continue to animate properly. </td> 3847 </tr> 3848 3849 <tr><td></td><td> There is no guarantee that the best optimization is found. But 3850 then no reasonably fast GIF optimization algorithm can do this. 3851 However this does seem to do better than most other GIF frame 3852 optimizers seen. </td> 3853 </tr> 3854 3855 <tr valign="top"> 3856 <td valign="top">optimize-plus</td> 3857 <td valign="top">As '<kbd>optimize-frame</kbd>' but attempt to improve the 3858 overall optimization by adding extra frames to the animation, without 3859 changing the final look or timing of the animation. The frames are 3860 added to attempt to separate the clearing of pixels from the 3861 overlaying of new additional pixels from one animation frame to the 3862 next. If this does not improve the optimization (for the next frame 3863 only), it will fall back to the results of the previous normal 3864 '<kbd>optimize-frame</kbd>' technique. </td> 3865 </tr> 3866 3867 <tr><td></td><td>There is the possibility that the change in the disposal style will 3868 result in a worsening in the optimization of later frames, though this 3869 is unlikely. In other words there no guarantee that it is better than 3870 the normal '<kbd>optimize-frame</kbd>' technique. For some animations 3871 however you can get a vast improvement in the final animation size. </td> 3872 </tr> 3873 3874 <tr valign="top"> 3875 <td valign="top">optimize-transparency</td> 3876 <td valign="top">Given a GIF animation, replace any pixel in the sub-frame 3877 overlay images with transparency, if it does not change the resulting 3878 animation by more than the current <a href="#fuzz" >-fuzz</a> factor. 3879 </td> 3880 </tr> 3881 3882 <tr><td></td><td>This should allow a existing frame optimized GIF animation to compress 3883 into a smaller file size due to larger areas of one (transparent) 3884 color rather than a pattern of multiple colors repeating the current 3885 disposed image of the last frame. </td> 3886 </tr> 3887 3888 <tr valign="top"> 3889 <td valign="top">remove-dups</td> 3890 <td valign="top">Remove (and merge time delays) of duplicate consecutive 3891 images, so as to simplify layer overlays of coalesced animations. 3892 </td> 3893 </tr> 3894 3895 <tr><td></td><td>Usually this a result of using a constant time delay across the 3896 whole animation, or after a larger animation was split into smaller 3897 sub-animations. The duplicate frames could also have been used as 3898 part of some frame optimization methods. </td> 3899 </tr> 3900 3901 <tr valign="top"> 3902 <td valign="top">remove-zero</td> 3903 <td valign="top">Remove any image with a zero time delay, unless ALL the 3904 images have a zero time delay (and is not a proper timed animation, a 3905 warning is then issued). </td> 3906 </tr> 3907 3908 <tr><td></td><td>In a GIF animation, such images are usually frames which provide 3909 partial intermediary updates between the frames that are actually 3910 displayed to users. These frames are usally added for improved frame 3911 optimization in GIF animations. </td> 3912 </tr> 3913 3914 <tr valign="top"> 3915 <td valign="top">trim-bounds</td> 3916 <td valign="top">Find the bounds of all the images in the current 3917 image sequence, then adjust the offsets so all images are contained on 3918 a minimal positive canvas. None of the image data is modified, only 3919 there virtual canvas size and offset. The all the image is given 3920 the same canvas size, and and will have a positive offset, but will 3921 remain in the same position relative to each other. As a result of the 3922 minimal canvas size at least one image will touch every edge of that 3923 canvas. The image data however may be transparent. 3924 </td> 3925 </tr> 3926 3927 </tbody> 3928</table> 3929 3930<p>To print a complete list of layer types, use <a href="#list">-list layers</a>.</p> 3931 3932<p>The operators <a href="#coalesce" >-coalesce</a>, <a href="#deconstruct" 3933>-deconstruct</a>, <a href="#flatten" >-flatten</a>, and <a href="#mosaic" 3934>-mosaic</a> are only aliases for the above methods. Also see <a 3935href="#page" >-page</a>, <a href="#repage" >-repage</a> operators, the <a 3936href="#compose" >-compose</a> setting, and the GIF <a href="#dispose" 3937>-dispose</a> and <a href="#delay" >-delay</a> settings. </p> 3938 3939 3940<div style="margin: auto;"> 3941 <h4><a id="level"></a>-level <em class="arg">black_point</em>{,<em class="arg">white_point</em>}{<em class="arg">%</em>}{,<em class="arg">gamma</em>}</h4> 3942</div> 3943 3944<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>adjust the level of image channels.</td><td style='text-align:right;'></td></tr></table> 3945 3946<p>Given one, two or three values delimited with commas: black-point, 3947white-point, gamma (for example: 10,250,1.0 or 2%,98%,0.5). The black and 3948white points range from 0 to <em class="QR">QuantumRange</em>, or from 0 to 100%; if the white 3949point is omitted it is set to (<em class="QR">QuantumRange</em> - black_point), so as to center 3950contrast changes. If a <kbd>%</kbd> sign is present anywhere in the string, 3951both black and white points are percentages of the full color range. Gamma 3952will do a <a href="#gamma">-gamma</a> adjustment of the values. If it is 3953omitted, the default of 1.0 (no gamma correction) is assumed.</p> 3954 3955<p>In normal usage (<kbd>-level</kbd>) the image values are stretched so that 3956the given '<kbd>black_point</kbd>' value in the original image is set to 3957zero (or black), while the given '<kbd>white_point</kbd>' value is set to 3958<em class="QR">QuantumRange</em> (or white). This provides you with direct contrast adjustments 3959to the image. The '<kbd>gamma</kbd>' of the resulting image will then be 3960adjusted. </p> 3961 3962<p>From ImageMagick v6.4.1-9 using the plus form of the operator (<kbd>+level</kbd>) or 3963adding the special '!' flag anywhere in the argument list, will cause the 3964operator to do the reverse of the level adjustment. That is a zero, or 3965<em class="QR">QuantumRange</em> value (black, and white, resp.) in the original image, is 3966adjusted to the given level values, allowing you to de-contrast, or compress 3967the channel values within the image. The '<kbd>gamma</kbd>' is adjusted before the level adjustment to de-contrast the image is made. </p> 3968 3969<p>Only the channels defined by the current <a href="#channel">-channel</a> 3970setting are adjusted (defaults to RGB color channels only), allowing you to 3971limit the effect of this operator. </p> 3972 3973<p>Please note that the transparency channel is treated as 'matte' 3974values (0 is opaque) and not as 'alpha' values (0 is transparent).</p> 3975 3976 3977<div style="margin: auto;"> 3978 <h4><a id="level-colors"></a>-level-colors {<em 3979 class="arg">black_color</em>}{,}{<em class="arg">white_color</em>}</h4> 3980</div> 3981 3982<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>adjust the level of an image using the provided dash separated colors.</td><td style='text-align:right;'></td></tr></table> 3983 3984<p>This function is exactly like <a href="#level">-level</a>, except that the 3985value value for each color channel is determined by the 3986'<kbd>black_color</kbd>' and '<kbd>white_color</kbd>' colors given (as 3987described under the <a href="#fill">-fill</a> option). </p> 3988 3989<p>This effectually means the colors provided to <kbd>-level-colors</kbd> 3990is mapped to become 'black' and 'white' respectively, with all the other 3991colors linearly adjusted (or clipped) to match that change. Each channel is 3992adjusted separately using the channel values of the colors specified. </p> 3993 3994<p>On the other hand the plus form of the operator (<kbd>+level-colors</kbd>) 3995will map the image color 'black' and 'white' to the given colors 3996respectively, resulting in a gradient (de-contrasting) tint of the image to 3997those colors. This can also be used to convert a plain gray-scale image into a 3998one using the gradient of colors specified. </p> 3999 4000<p>By supplying a single color with a comma separator either before or after 4001that color, will just replace the respective 'black' or 'white' point 4002respectively. But if no comma separator is provided, the given color is 4003used for both the black and white color points, making the operator either 4004threshold the images around that color (- form) or set all colors to that 4005color (+ form). </p> 4006 4007 4008<div style="margin: auto;"> 4009 <h4><a id="limit"></a>-limit <em class="arg">type value</em></h4> 4010</div> 4011 4012<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the pixel cache resource limit.</td><td style='text-align:right;'></td></tr></table> 4013 4014<p>Choose from: <kbd>area</kbd>, <kbd>disk</kbd>, <kbd>file</kbd>, <kbd>map</kbd>, <kbd>memory</kbd>, <kbd>threads</kbd>, or <kbd>time</kbd>.</p> 4015 4016<p>The value for <kbd>file</kbd> is in number of files. The other limits are in bytes. By default the limits are 768 files, 2GB of image area, 1.5GiB memory, 8GiB memory map, and 18.45EB of disk. These limits are adjusted relative to the available resources on your computer if this information is available. When any limit is reached, ImageMagick fails in some fashion but attempts to take compensating actions, if possible. For example, the following limits memory:</p> 4017 4018<p class="crtsnip"> 4019 -limit memory 32MiB -limit map 64MiB 4020</p> 4021 4022<p>Use <a href="#list">-list resource</a> to list the current limits. For example, our system shows these limits:</p> 4023 4024<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>identify -list resource</span><span class='crtout'></span></p><pre class="text"> 4025File Area Memory Map Disk Thread Time 4026------------------------------------------------------------------------------ 4027 768 12.404GB 8.6642GiB 23.104GiB 18.446744EB 8 unlimited 4028</pre> 4029 4030<p>Requests for pixel storage to keep intermediate images are satisfied by one of three resource categories: in-memory pool, memory-mapped files pool, and disk pool (in that order) depending on the <a href="/www/command-line-options.html#limit">‑limit</a> settings and whether the system honors a resource request. If the total size of allocated pixel storage in the given pool reaches the corresponding limit, the request is passed to the next pool. Additionally, requests that exceed the <kbd>area</kbd> limit automagically are allocated on disk.</p> 4031 4032<p>To illustrate how ImageMagick utilizes resource limits, consider a typical image resource request. First, ImageMagick tries to allocate the pixels in memory. The request might be denied if the resource request exceeds the <kbd>memory</kbd> limit or if the system does not honor the request. If a memory request is not honored, the pixels are allocated to disk and the file is memory-mapped. However, if the allocation request exceeds the <kbd>map</kbd> limit, the resource allocation goes to disk. In all cases, if the resource request exceeds the <kbd>area</kbd> limit, the pixels are automagically cached to disk. If the disk has a hard limit, the program fails.</p> 4033 4034<p>In most cases you simply do not need to concern yourself with resource limits. ImageMagick chooses reasonable defaults and most images do not tax your computer resources. Where limits do come in handy is when you process images that are large or on shared systems where ImageMagick can consume all or most of the available memory. In this case, the ImageMagick workflow slows other processes or, in extreme cases, brings the system to a halt. Under these circumstances, setting limits give some assurances that the ImageMagick workflow will not interfere with other concurrent uses of the computer. For example, assume you have a web interface that processes images uploaded from the Internet. To assure ImageMagick does not exceed 10mb of memory you can simply set the area limit to 10mb:</p> 4035 4036<p class="crtsnip"> 4037-limit area 10mb 4038</p> 4039 4040<p>Now whenever a large image is processed, the pixels are automagically cached to disk instead of memory. This of course implies that large images typically process very slowly, simply because pixel processing in memory can be an order of magnitude faster than on disk. Because your web site users might inadvertently upload a huge image to process, you should set a disk limit as well:</p> 4041 4042<p class="crtsnip"> 4043-limit area 10mb -limit disk 500mb 4044</p> 4045 4046<p>Here ImageMagick stops processing if an image requires more than 500MB of disk storage.</p> 4047 4048<p>In addition to command-line resource limit option, resources can be set with <a href="/www/resources.html#environment">environment variables</a>. Set the environment variables <kbd>MAGICK_AREA_LIMIT</kbd>, <kbd>MAGICK_DISK_LIMIT</kbd>, <kbd>MAGICK_FILE_LIMIT</kbd>, <kbd>MAGICK_MEMORY_LIMIT</kbd>, <kbd>MAGICK_MAP_LIMIT</kbd>, <kbd>MAGICK_THREAD_LIMIT</kbd>, <kbd>MAGICK_TIME_LIMIT</kbd> for limits of image area, disk space, open files, heap memory, memory map, number of threads of execution, and maximum elapsed time in seconds respectively.</p> 4049 4050<p> Inquisitive users can try adding <a href="#debug">-debug cache</a> to their commands and then scouring the generated output for references to the pixel cache, in order to determine how the pixel cache was allocated and how resources were consumed. Advanced Unix/Linux users can pipe that output through <kbd>grep memory|open|destroy|disk</kbd> for more readable sifting. 4051</p> 4052 4053<p>For more about ImageMagick's use of resources, see the section <b>Cache Storage and Resource Requirements</b> on the <a href="/www/architecture.html#cache">Architecture</a> page. 4054</p> 4055 4056<div style="margin: auto;"> 4057 <h4><a id="linear-stretch"></a>-linear-stretch <em class="arg">black-point</em><br />-linear-stretch <em class="arg">black-point</em>{x<em class="arg">white-point</em>}{<em class="arg">%</em>}}</h4> 4058</div> 4059 4060<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Linear with saturation stretch.</td><td style='text-align:right;'></td></tr></table> 4061 4062<p>This is very similar to <a href="#contrast-stretch" >-contrast-stretch</a>, 4063and uses a 'histogram bin' to determine the range of color values that needs to 4064be stretched. However it then stretchs those colors using the <a 4065href="#level" >-level</a> operator.</p> 4066 4067<p>As such while the initial determination may have 'binning' round off 4068effects, the image colors are stretched mathematically, rather than using the 4069histogram bins. This makes the operator more accurate. </p> 4070 4071<p>note however that a <a href="#linear-stretch" >-linear-stretch</a> of 4072'<kbd>0</kbd>' does nothing, while a value of '<kbd>1</kbd>' does a near 4073perfect stretch of the color range. </p> 4074 4075<p>See also <a href="#auto-level" >-auto-level</a> for a 'perfect' 4076normalization of mathematical images. </p> 4077 4078<p>This operator is under review for re-development. </p> 4079 4080 4081<div style="margin: auto;"> 4082 <h4><a id="linewidth"></a>-linewidth</h4> 4083</div> 4084 4085<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the line width for subsequent draw operations.</td><td style='text-align:right;'></td></tr></table> 4086 4087<div style="margin: auto;"> 4088 <h4><a id="liquid-rescale"></a>-liquid-rescale <em class="arg">geometry</em></h4> 4089</div> 4090 4091<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>rescale image with seam-carving.</td><td style='text-align:right;'></td></tr></table> 4092 4093<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 4094 4095<div style="margin: auto;"> 4096 <h4><a id="list"></a>-list <em class="arg">type</em></h4> 4097</div> 4098 4099<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Print a list of supported arguments for various options or settings. Choose from these list types:</td><td style='text-align:right;'></td></tr></table> 4100 4101<pre class="text"> 4102 Align 4103 Alpha 4104 Boolean 4105 Channel 4106 Class 4107 ClipPath 4108 Coder 4109 Color 4110 Colorspace 4111 Command 4112 Compose 4113 Compress 4114 Configure 4115 DataType 4116 Debug 4117 Decoration 4118 Delegate 4119 Direction 4120 Dispose 4121 Distort 4122 Dither 4123 Endian 4124 Evaluate 4125 FillRule 4126 Filter 4127 Font 4128 Format 4129 Function 4130 Gravity 4131 ImageList 4132 Intent 4133 Interlace 4134 Interpolate 4135 Kernel 4136 Layers 4137 LineCap 4138 LineJoin 4139 List 4140 Locale 4141 LogEvent 4142 Log 4143 Magic 4144 Method 4145 Metric 4146 Mime 4147 Mode 4148 Morphology 4149 Module 4150 Noise 4151 Orientation 4152 Policy 4153 PolicyDomain 4154 PolicyRights 4155 Preview 4156 Primitive 4157 QuantumFormat 4158 Resource 4159 SparseColor 4160 Storage 4161 Stretch 4162 Style 4163 Threshold 4164 Type 4165 Units 4166 Validate 4167 VirtualPixel 4168</pre> 4169 4170<p>These lists vary depending on your version of ImageMagick. Use "<kbd>-list 4171list</kbd>" to get a complete listing of all the "<kbd>-list</kbd>" arguments 4172available:</p> 4173 4174<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>identify -list list</span></p> 4175<div style="margin: auto;"> 4176 <h4><a id="log"></a>-log <em class="arg">string</em></h4> 4177</div> 4178 4179<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specify format for debug log.</td><td style='text-align:right;'></td></tr></table> 4180 4181<p>This option specifies the format for the log printed when the <a 4182href="#debug">-debug</a> option is active.</p> 4183 4184<p>You can display the following components by embedding special format 4185characters:</p> 4186 4187<pre class="text"> 4188 %d domain 4189 %e event 4190 %f function 4191 %l line 4192 %m module 4193 %p process ID 4194 %r real CPU time 4195 %t wall clock time 4196 %u user CPU time 4197 %% percent sign 4198 \n newline 4199 \r carriage return 4200</pre> 4201 4202<p>For example:</p> 4203 4204<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -debug coders -log "%u %m:%l %e" in.gif out.png</span></p> 4205<p>The default behavior is to print all of the components.</p> 4206 4207<div style="margin: auto;"> 4208 <h4><a id="loop"></a>-loop <em class="arg">iterations</em></h4> 4209</div> 4210 4211<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>add Netscape loop extension to your GIF animation.</td><td style='text-align:right;'></td></tr></table> 4212 4213<p>Set iterations to zero to repeat the animation an infinite number of times, 4214otherwise the animation repeats itself up to <em class="arg">iterations</em> 4215times.</p> 4216 4217<div style="margin: auto;"> 4218 <h4><a id="lowlight-color"></a>-lowlight-color <em class="arg">color</em></h4> 4219</div> 4220 4221<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>when comparing images, de-emphasize pixel differences with this color.</td><td style='text-align:right;'></td></tr></table> 4222 4223<div style="margin: auto;"> 4224 <h4><a id="magnify"></a>-magnify <em class="arg">factor</em></h4> 4225</div> 4226 4227<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>magnify the image.</td><td style='text-align:right;'></td></tr></table> 4228 4229 4230<div style="margin: auto;"> 4231 <h4><a id="map"></a>-map <em class="arg">type</em></h4> 4232</div> 4233 4234<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Display image using this <em class="arg">type</em>.</td><td style='text-align:right;'>[<a href="/www/animate.html">animate</a>, <a href="/www/display.html">display</a>]</td></tr></table> 4235 4236<p>Choose from these <em class="arg">Standard Colormap</em> types:</p> 4237 4238<pre class="text"> 4239 best 4240 default 4241 gray 4242 red 4243 green 4244 blue 4245</pre> 4246 4247<p>The <em class="arg">X server</em> must support the <em class="arg">Standard 4248Colormap</em> you choose, otherwise an error occurs. Use <kbd>list</kbd> as 4249the type and <kbd>display</kbd> searches the list of colormap types in 4250<kbd>top-to-bottom</kbd> order until one is located. See <em 4251class="arg">xstdcmap(1)</em> for one way of creating Standard Colormaps.</p> 4252 4253 4254<div style="margin: auto;"> 4255 <h4><a id="map_stream_"></a>-map <em class="arg">components</em></h4> 4256</div> 4257 4258<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>pixel map.</td><td style='text-align:right;'>[<a href="/www/stream.html">stream</a>]</td></tr></table> 4259 4260<p>Here are the valid components of a map:</p> 4261 4262<pre class="text"> 4263 r red pixel component 4264 g green pixel component 4265 b blue pixel component 4266 a alpha pixel component (0 is transparent) 4267 o opacity pixel component (0 is opaque) 4268 i grayscale intensity pixel component 4269 c cyan pixel component 4270 m magenta pixel component 4271 y yellow pixel component 4272 k black pixel component 4273 p pad component (always 0) 4274</pre> 4275 4276<p>You can specify as many of these components as needed in any order (e.g. 4277bgr). The components can repeat as well (e.g. rgbr).</p> 4278 4279 4280<div style="margin: auto;"> 4281 <h4><a id="mask"></a>-mask 4282<em class="arg">filename</em></h4> 4283</div> 4284 4285<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Composite the image pixels as defined by the mask.</td><td style='text-align:right;'></td></tr></table> 4286 4287<p>Use <a href="#mask">+mask</a> to remove the image mask.</p> 4288 4289<div style="margin: auto;"> 4290 <h4><a id="mattecolor"></a>-mattecolor <em class="arg">color</em></h4> 4291</div> 4292 4293<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specify the color to be used with the <a href="#frame">-frame</a> option.</td><td style='text-align:right;'></td></tr></table> 4294 4295<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 4296 4297<p>The default matte color is <kbd>#BDBDBD</kbd>, <span 4298style="background-color: #bdbdbd;">this shade of gray</span>.</p> 4299 4300<div style="margin: auto;"> 4301 <h4><a id="maximum"></a>-maximum</h4> 4302</div> 4303 4304<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>return the maximum intensity of an image sequence.</td><td style='text-align:right;'></td></tr></table> 4305 4306<div style="margin: auto;"> 4307 <h4><a id="median"></a>-median <em class="arg">radius</em></h4> 4308</div> 4309 4310<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>apply a median filter to the image.</td><td style='text-align:right;'></td></tr></table> 4311 4312<div style="margin: auto;"> 4313 <h4><a id="metric"></a>-metric <em class="arg">type</em></h4> 4314</div> 4315 4316<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Output to STDERR a measure of the differences between images according to the <em class="arg">type</em> given metric.</td><td style='text-align:right;'></td></tr></table> 4317 4318<p>Choose from:</p> 4319 4320<pre class="text"> 4321 AE absolute error count, number of different pixels (-fuzz effected) 4322 FUZZ mean color distance 4323 MAE mean absolute error (normalized), average channel error distance 4324 MEPP mean error per pixel (normalized mean error, normalized peak error) 4325 MSE mean error squared, average of the channel error squared 4326 NCC normalized cross correlation 4327 PAE peak absolute (normalize peak absolute) 4328 PSNR peak signal to noise ratio 4329 RMSE root mean squared (normalized root mean squared) 4330</pre> 4331 4332<p>Control the '<kbd>AE</kbd>', or absolute count of pixels that are different, 4333with the <a href="#fuzz" >-fuzz</a> factor (ignore pixels which 4334only changed by a small amount). Use '<kbd>PAE</kbd>' to find the 4335size of the <a href="#fuzz" >-fuzz</a> factor needed to make all pixels 4336'similar', while '<kbd>MAE</kbd>' dtermines the factor needed 4337for about half the pixels to be similar. </p> 4338 4339<p>The '<kbd>MEPP</kbd>' metric returns three different metrics 4340('<kbd>MAE</kbd>', '<kbd>MAE</kbd>' normalized, and '<kbd>PAE</kbd>' 4341normalized) from a single comparison run. </p> 4342 4343<p>To print a complete list of metrics, use the <a href="#list">-list 4344metrics</a> option.</p> 4345 4346 4347<div style="margin: auto;"> 4348 <h4><a id="minimum"></a>-minimum</h4> 4349</div> 4350 4351<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>return the minimum intensity of an image sequence.</td><td style='text-align:right;'></td></tr></table> 4352 4353 4354<div style="margin: auto;"> 4355 <h4><a id="mode"></a>-mode <em class="arg">value</em></h4> 4356</div> 4357 4358<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>make each pixel the 'predominate color' of the neighborhood.</td><td style='text-align:right;'>[<a href="/www/convert.html">convert</a>, <a href="/www/mogrify.html">mogrify</a>]</td></tr></table> 4359 4360<div style="margin: auto;"> 4361 <h4>-mode <em class="arg">value</em></h4> 4362</div> 4363 4364<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Mode of operation.</td><td style='text-align:right;'>[<a href="/www/montage.html">montage</a>]</td></tr></table> 4365 4366<p>Choose the <em class="arg">value</em> from these styles: <kbd>Frame, 4367Unframe, or Concatenate</kbd></p> 4368 4369<p>Use the <a href="#list" >-list</a> option with a '<kbd>Mode</kbd>' argument 4370for a list of <a href="#mode" >-mode</a> arguments available in your 4371ImageMagick installation.</p> 4372 4373 4374<div style="margin: auto;"> 4375 <h4><a id="modulate"></a>-modulate <em class="arg">brightness</em>[,<em class="arg">saturation</em>,<em class="arg">hue</em>]</h4> 4376</div> 4377 4378<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Vary the <em class="arg">brightness</em>, <em 4379class="arg">saturation</em>, and <em class="arg">hue</em> of an image.</td><td style='text-align:right;'></td></tr></table> 4380 4381<p>The arguments are given as a percentages of variation. A value of 100 means 4382no change, and any missing values are taken to mean 100.</p> 4383 4384<p>The <em class="arg">brightness</em> is a multiplier of the overall 4385brightness of the image, so 0 means pure black, 50 is half as bright, 200 is 4386twice as bright. To invert its meaning <a href="#negate">-negate</a> the image 4387before and after. </p> 4388 4389<p>The <em class="arg">saturation</em> controls the amount of color in an 4390image. For example, 0 produce a grayscale image, while a large value such as 4391200 produce a very colorful, 'cartoonish' color.</p> 4392 4393<p>The <em class="arg">hue</em> argument causes a "rotation" of the colors 4394within the image by the amount specified. For example, 50 results in 4395a counter-clockwise rotation of 90, mapping red shades to purple, and so on. 4396A value of either 0 or 200 results in a complete 180 degree rotation of the 4397image. Using a value of 300 is a 360 degree rotation resulting in no change to 4398the original image. </p> 4399 4400<p>For example, to increase the color brightness by 20% and decrease the color 4401saturation by 10% and leave the hue unchanged, use <a 4402href="#modulate">-modulate 120,90</a>.</p> 4403 4404<p>Use <a href="#set">-set</a> attribute of '<kbd 4405class="arg">option:modulate:colorspace</kbd>' to specify which colorspace to 4406modulate. Choose from <kbd>HSB</kbd>, <kbd>HSL</kbd> (the default), or 4407<kbd>HWB</kbd>. For example,</p> 4408 4409<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -set option:modulate:colorspace hsb -modulate 120,90 modulate.png</span></p> 4410 4411<div style="margin: auto;"> 4412 <h4><a id="monitor"></a>-monitor</h4> 4413</div> 4414 4415<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>monitor progress.</td><td style='text-align:right;'></td></tr></table> 4416 4417 4418<div style="margin: auto;"> 4419 <h4><a id="monochrome"></a>-monochrome</h4> 4420</div> 4421 4422<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>transform the image to black and white.</td><td style='text-align:right;'></td></tr></table> 4423 4424 4425<div style="margin: auto;"> 4426 <h4><a id="morph"></a>-morph <em class="arg">frames</em></h4> 4427</div> 4428 4429<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>morphs an image sequence.</td><td style='text-align:right;'></td></tr></table> 4430 4431<p>Both the image pixels and size are linearly interpolated to give the 4432appearance of a meta-morphosis from one image to the next, over all the images 4433in the current image list. The added images are the equivalent of a <a 4434href="#blend">-blend</a> composition. The <em class="arg">frames</em> 4435argument determine how many images to interpolate between each image. </p> 4436 4437 4438<div style="margin: auto;"> 4439 <h4><a id="morphology"></a>-morphology</h4> 4440 <h4>-morphology <em class="arg">method</em> <em class="arg">kernel</em></h4> 4441</div> 4442 4443<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>apply a morphology method to the image.</td><td style='text-align:right;'></td></tr></table> 4444 4445<p>Until I get around to writing a option summary for this, see <a 4446href="http://www.imagemagick.org/Usage/morphology/" >IM Usage Examples, 4447Morphology</a>. </p> 4448 4449 4450<div style="margin: auto;"> 4451 <h4><a id="mosaic"></a>-mosaic</h4> 4452</div> 4453 4454<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>an simple alias for the <a href="#layers" >-layers</a> method "mosaic"</td><td style='text-align:right;'></td></tr></table> 4455 4456 4457<div style="margin: auto;"> 4458 <h4><a id="motion-blur"></a>-motion-blur <em class="arg">radius</em><br />-motion-blur <em class="arg">radius</em>x<em class="arg">sigma</em>+<em class="arg">angle</em></h4> 4459</div> 4460 4461<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>simulate motion blur.</td><td style='text-align:right;'></td></tr></table> 4462 4463<p>Blur with the given radius, standard deviation (sigma), and angle. The 4464angle given is the angle toward which the image is blurred. That is the 4465direction people would consider the object is coming from. </p> 4466 4467<p>Note that the blur is not uniform distribution, giving the motion a 4468definite sense of direction of movement. </p> 4469 4470<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 4471pixels which are outside the image proper are blurred into the final result. 4472</p> 4473 4474<div style="margin: auto;"> 4475 <h4><a id="name"></a>-name</h4> 4476</div> 4477 4478<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>name an image.</td><td style='text-align:right;'></td></tr></table> 4479<div style="margin: auto;"> 4480 <h4><a id="negate"></a>-negate</h4> 4481</div> 4482 4483<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>replace each pixel with its complementary color.</td><td style='text-align:right;'></td></tr></table> 4484 4485<p>The red, green, and blue intensities of an image are negated. White becomes black, yellow becomes blue, etc. Use <a href="#negate">+negate</a> to only negate the grayscale pixels of the image.</p> 4486 4487<div style="margin: auto;"> 4488 <h4><a id="noise"></a>-noise <em class="arg">radius</em><br/> 4489 +noise <em class="arg">type</em></h4> 4490</div> 4491 4492<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Add or reduce noise in an image.</td><td style='text-align:right;'></td></tr></table> 4493 4494<p>The principal function of noise peak elimination filter is to smooth the objects within an image without losing edge information and without creating undesired structures. The central idea of the algorithm is to replace a pixel with its next neighbor in value within a pixel window, if this pixel has been found to be noise. A pixel is defined as noise if and only if this pixel is a maximum or minimum within the pixel window.</p> 4495 4496<p>Use <kbd><a href="#noise">-noise</a> <em class="arg">radius</em></kbd> to specify the width of the neighborhood when reducing noise.</p> 4497 4498<p>Use <a href="#noise">+noise</a> followed by a noise <em class="arg">type</em> to add noise to an image. Choose from these noise types:</p> 4499 4500<pre class="text"> 4501Gaussian 4502Impulse 4503Laplacian 4504Multiplicative 4505Poisson 4506Random 4507Uniform 4508</pre> 4509 4510<p>To print a complete list of noises, use the <a href="#list">-list noise</a> option.</p> 4511 4512<p>Also see the <a href="#evaluate">-evaluate</a> noise functions that allos 4513the use of a controlling value to specify teh amount of noise that should be 4514added to an image. </p> 4515 4516 4517<div style="margin: auto;"> 4518 <h4><a id="normalize"></a>-normalize</h4> 4519</div> 4520 4521<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Increase the contrast in an image by <em>stretching</em> the range of intensity values.</td><td style='text-align:right;'></td></tr></table> 4522 4523<p>The intensity values are stretched to cover the entire range of possible 4524values. While doing so, black-out at most <em>2%</em> of the pixels and 4525white-out at most <em>1%</em> of the pixels.</p> 4526 4527<p>Note that as of ImageMagick 6.4.7-0, <a href="#normalize" >-normalize</a> 4528is equivalent to <a href="#contrast-stretch" >-contrast-stretch 2%x1%</a>. 4529(Before this version, it was equivalent to <a href="#contrast-stretch" 4530>-contrast-stretch 2%x99%</a>).</p> 4531 4532<p>All the channels are normalized in concert by the came amount so as to 4533preserve color integrity, when the default <a href="#channel" >+channel</a> 4534setting is in use. Specifying any other <a href="#channel" >-channel</a> 4535setting will normalize the RGB channels independently.</p> 4536 4537<p>See <a href="#contrast-stretch" >-contrast-stretch</a> for more details. 4538Also see <a href="#auto-level" >-auto-level</a> for a 'perfect' normalization 4539that is better suited to mathematically generated images. </p> 4540 4541<p>This operator is under review for re-development. </p> 4542 4543 4544<div style="margin: auto;"> 4545 <h4><a id="ordered-dither"></a>-ordered-dither <em class="arg">threshold_map</em>{,<em class="arg">level</em>...}</h4> 4546</div> 4547 4548<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>dither the image using a pre-defined ordered dither <em 4549class="arg">threshold map</em> specified, and a uniform color map with the 4550given number of <em class="arg">levels</em> per color channel . </td><td style='text-align:right;'></td></tr></table> 4551 4552<p>You can choose from these standard threshold maps:</p> 4553 4554<pre class="text"> 4555threshold 1x1 Threshold 1x1 (non-dither) 4556checks 2x1 Checkerboard 2x1 (dither) 4557o2x2 2x2 Ordered 2x2 (dispersed) 4558o3x3 3x3 Ordered 3x3 (dispersed) 4559o4x4 4x4 Ordered 4x4 (dispersed) 4560o8x8 8x8 Ordered 8x8 (dispersed) 4561h4x4a 4x1 Halftone 4x4 (angled) 4562h6x6a 6x1 Halftone 6x6 (angled) 4563h8x8a 8x1 Halftone 8x8 (angled) 4564h4x4o Halftone 4x4 (orthogonal) 4565h6x6o Halftone 6x6 (orthogonal) 4566h8x8o Halftone 8x8 (orthogonal) 4567h16x16o Halftone 16x16 (orthogonal) 4568c5x5b c5x5 Circles 5x5 (black) 4569c5x5w Circles 5x5 (white) 4570c6x6b c6x6 Circles 6x6 (black) 4571c6x6w Circles 6x6 (white) 4572c7x7b c7x7 Circles 7x7 (black) 4573c7x7w Circles 7x7 (white) 4574</pre> 4575 4576<p> The <kbd>checks</kbd> pattern produces a 3 level checkerbord dither 4577pattern. Or you can define your own <em class="arg" >threshold map</em> in a 4578personal or system <kbd>thresholds.xml</kbd> XML file. </p> 4579 4580<p>To print a complete list of threshold, use the <a href="#list" >-list 4581threshold</a> option.</p> 4582 4583<p>It is recommended that the <a href="#map" >+map</a> operator be used after 4584applying <a href="#ordered-dither" >-ordered-dither</a> to reduce the number of 4585colors an animated image sequence, to less that 256 colors. This ensures that 4586a common or global color table is used when saving the result to a color 4587limited file format such as GIF. </p> 4588 4589<p>Note that at this time the exact same threshold dithering map is used for 4590all color channels, no attempt is made to offset or rotate the map for 4591different channels is made, to create an offset printing effect. (possible 4592future expansion) </p> 4593 4594 4595<div style="margin: auto;"> 4596 <h4><a id="opaque"></a>-opaque <em class="arg">color</em></h4> 4597</div> 4598 4599<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>change this color to the fill color within the image.</td><td style='text-align:right;'></td></tr></table> 4600 4601<p>The <em class="arg">color</em> argument is defined using the format 4602described under the <a href="#fill" >-fill</a> option. The <a href="#fuzz" 4603>-fuzz</a> setting can be used to match and replace colors similar to the one 4604given.</p> 4605 4606<p>Use <a href="#opaque">+opaque</a> to paint any pixel that does not match 4607the target color. </p> 4608 4609<p>The <a href="#transparent">-transparent</a> operator is exactly the same 4610as <a href="#opaque" >-opaque</a> but replaces the matching color with 4611transparency rather than the current <a href="#fill">-fill</a> color setting. 4612To ensure that it can do this it also ensures that the image has an alpha 4613channel enabled, as per "<kbd><a href="#alpha" >-alpha</a> set</kbd>", for 4614the new transparent colors, and does not require you to modify the <a 4615href="#channel">-channel</a> to enable alpha channel handling. </p> 4616 4617 4618<div style="margin: auto;"> 4619 <h4><a id="orient"></a>-orient <em class="arg">image orientation</em></h4> 4620</div> 4621 4622<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>specify orientation of a digital camera image.</td><td style='text-align:right;'></td></tr></table> 4623 4624<p>Choose from these orientations:</p> 4625 4626<pre class="text"> 4627 bottom-left 4628 bottom-right 4629 left-bottom 4630 left-top 4631 right-bottom 4632 right-top 4633 top-left 4634 top-right 4635 undefined 4636</pre> 4637 4638<p>To print a complete list of orientations, use the <a href="#list" >-list 4639orientation</a> option.</p> 4640 4641 4642<div style="margin: auto;"> 4643 <h4><a id="page"></a>-page <em class="arg">geometry</em><br/> 4644 -page <em class="arg">media</em>[<em class="arg">offset</em>][{<em class="arg">^!<></em>}]<br/> 4645 +page 4646 </h4> 4647</div> 4648 4649<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the size and location of an image on the larger virtual canvas.</td><td style='text-align:right;'></td></tr></table> 4650 4651<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 4652 4653<p>For convenience you can specify the page size using <em class="arg">media</em> (see below). Offsets can then be added as with other <em class="arg">geometry</em> arguments (e.g. <a href="#page">-page</a> <kbd>Letter+43+43</kbd>).</p> 4654 4655<p>Use <em class="arg">media</em> as shorthand to specify the dimensions (<em class="arg">width</em>x<em class="arg">height</em>) of the <em class="arg">PostScript</em> page in dots per inch or a TEXT page in pixels. The choices for a PostScript page are:</p> 4656<table id="geometryTable" cellpadding="2" cellspacing="0" border="1" width="50%" style="margin-left: auto; margin-right: auto;"> 4657<thead> 4658 <tr valign="top"> 4659 <th align="center"><em class="arg">media</em></th> 4660 <th align="center"><em class="arg">width</em></th> 4661 <th align="center"><em class="arg">height</em></th> 4662 </tr> 4663</thead> 4664<tbody> 4665<tr><td align="left"> 11x17 </td> <td align="right"> 792</td> <td align="right"> 1224</td> </tr> 4666<tr><td align="left"> Ledger </td> <td align="right"> 1224</td> <td align="right"> 792</td> </tr> 4667<tr><td align="left"> Legal </td> <td align="right"> 612</td> <td align="right"> 1008</td> </tr> 4668<tr><td align="left"> Letter </td> <td align="right"> 612</td> <td align="right"> 792</td> </tr> 4669<tr><td align="left"> LetterSmall</td> <td align="right"> 612</td> <td align="right"> 792</td> </tr> 4670<tr><td align="left"> ArchE </td> <td align="right"> 2592</td> <td align="right"> 3456</td> </tr> 4671<tr><td align="left"> ArchD </td> <td align="right"> 1728</td> <td align="right"> 2592</td> </tr> 4672<tr><td align="left"> ArchC </td> <td align="right"> 1296</td> <td align="right"> 1728</td> </tr> 4673<tr><td align="left"> ArchB </td> <td align="right"> 864</td> <td align="right"> 1296</td> </tr> 4674<tr><td align="left"> ArchA </td> <td align="right"> 648</td> <td align="right"> 864</td> </tr> 4675<tr><td align="left"> A0 </td> <td align="right"> 2380</td> <td align="right"> 3368</td> </tr> 4676<tr><td align="left"> A1 </td> <td align="right"> 1684</td> <td align="right"> 2380</td> </tr> 4677<tr><td align="left"> A2 </td> <td align="right"> 1190</td> <td align="right"> 1684</td> </tr> 4678<tr><td align="left"> A3 </td> <td align="right"> 842</td> <td align="right"> 1190</td> </tr> 4679<tr><td align="left"> A4 </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr> 4680<tr><td align="left"> A4Small </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr> 4681<tr><td align="left"> A5 </td> <td align="right"> 421</td> <td align="right"> 595</td> </tr> 4682<tr><td align="left"> A6 </td> <td align="right"> 297</td> <td align="right"> 421</td> </tr> 4683<tr><td align="left"> A7 </td> <td align="right"> 210</td> <td align="right"> 297</td> </tr> 4684<tr><td align="left"> A8 </td> <td align="right"> 148</td> <td align="right"> 210</td> </tr> 4685<tr><td align="left"> A9 </td> <td align="right"> 105</td> <td align="right"> 148</td> </tr> 4686<tr><td align="left"> A10 </td> <td align="right"> 74</td> <td align="right"> 105</td> </tr> 4687<tr><td align="left"> B0 </td> <td align="right"> 2836</td> <td align="right"> 4008</td> </tr> 4688<tr><td align="left"> B1 </td> <td align="right"> 2004</td> <td align="right"> 2836</td> </tr> 4689<tr><td align="left"> B2 </td> <td align="right"> 1418</td> <td align="right"> 2004</td> </tr> 4690<tr><td align="left"> B3 </td> <td align="right"> 1002</td> <td align="right"> 1418</td> </tr> 4691<tr><td align="left"> B4 </td> <td align="right"> 709</td> <td align="right"> 1002</td> </tr> 4692<tr><td align="left"> B5 </td> <td align="right"> 501</td> <td align="right"> 709</td> </tr> 4693<tr><td align="left"> C0 </td> <td align="right"> 2600</td> <td align="right"> 3677</td> </tr> 4694<tr><td align="left"> C1 </td> <td align="right"> 1837</td> <td align="right"> 2600</td> </tr> 4695<tr><td align="left"> C2 </td> <td align="right"> 1298</td> <td align="right"> 1837</td> </tr> 4696<tr><td align="left"> C3 </td> <td align="right"> 918</td> <td align="right"> 1298</td> </tr> 4697<tr><td align="left"> C4 </td> <td align="right"> 649</td> <td align="right"> 918</td> </tr> 4698<tr><td align="left"> C5 </td> <td align="right"> 459</td> <td align="right"> 649</td> </tr> 4699<tr><td align="left"> C6 </td> <td align="right"> 323</td> <td align="right"> 459</td> </tr> 4700<tr><td align="left"> Flsa </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr> 4701<tr><td align="left"> Flse </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr> 4702<tr><td align="left"> HalfLetter </td> <td align="right"> 396</td> <td align="right"> 612</td> </tr> 4703</tbody> 4704</table> 4705 4706 4707 4708 4709<p>This option is also used to place subimages when writing to a multi-image format that supports offsets, such as GIF89 and MNG. When used for this purpose the offsets are always measured from the top left corner of the canvas and are not affected by the <a href="#gravity">-gravity</a> option. To position a GIF or MNG image, use <a href="#page">-page</a><em class="arg">{+-}x{+-}y</em> (e.g. -page +100+200). When writing to a MNG file, a <a href="#page">-page</a> option appearing ahead of the first image in the sequence with nonzero width and height defines the width and height values that are written in the <kbd>MHDR</kbd> chunk. Otherwise, the MNG width and height are computed from the bounding box that contains all images in the sequence. When writing a GIF89 file, only the bounding box method is used to determine its dimensions.</p> 4710 4711<p>For a PostScript page, the image is sized as in <a href="#geometry">-geometry</a> but positioned relative to the <em>lower left-hand corner</em> of the page by {+-}<kbd>x</kbd><em class="arg">offset</em>{+-}<kbd>y</kbd> <em class="arg">offset</em>. Use <a href="#page">-page 612x792</a>, for example, to center the image within the page. If the image size exceeds the PostScript page, it is reduced to fit the page. The default gravity for the <a href="#page">-page</a> option is <em class="arg">NorthWest</em>, i.e., positive <kbd>x</kbd> and <kbd>y</kbd> <em class="arg">offset</em> are measured rightward and downward from the top left corner of the page, unless the <a href="#gravity">-gravity</a> option is present with a value other than <em class="arg">NorthWest</em>.</p> 4712 4713<p>The default page dimensions for a TEXT image is 612x792.</p> 4714 4715<p>This option is used in concert with <a href="#density">-density</a>.</p> 4716 4717<p>Use <a href="#page">+page</a> to remove the page settings for an image.</p> 4718 4719<div style="margin: auto;"> 4720 <h4><a id="paint"></a>-paint <em class="arg">radius</em></h4> 4721</div> 4722 4723<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>simulate an oil painting.</td><td style='text-align:right;'></td></tr></table> 4724 4725<p>Each pixel is replaced by the most frequent color in a circular neighborhood whose width is specified with <em class="arg">radius</em>.</p> 4726 4727<div style="margin: auto;"> 4728 <h4><a id="path"></a>-path <em class="arg">path</em></h4></div> 4729 4730<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>write images to this path on disk.</td><td style='text-align:right;'></td></tr></table> 4731 4732<div style="margin: auto;"> 4733 <h4><a id="pause_animate_"></a>-pause <em class="arg">seconds</em></h4> 4734</div> 4735 4736<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Pause between animation loops.</td><td style='text-align:right;'>[<a href="/www/animate.html">animate</a>]</td></tr></table> 4737 4738<p>Pause for the specified number of seconds before repeating the animation.</p> 4739 4740<div style="margin: auto;"> 4741 <h4><a id="pause_import_"></a>-pause <em class="arg">seconds</em></h4> 4742</div> 4743 4744<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Pause between snapshots.</td><td style='text-align:right;'>[<a href="/www/import.html">import</a>]</td></tr></table> 4745 4746<p>Pause for the specified number of seconds before taking the next snapshot.</p> 4747 4748<div style="margin: auto;"> 4749 <h4><a id="ping"></a>-ping</h4> 4750</div> 4751 4752<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>efficiently determine image characteristics.</td><td style='text-align:right;'></td></tr></table> 4753 4754<div style="margin: auto;"> 4755 <h4><a id="pointsize"></a>-pointsize <em class="arg">value</em></h4> 4756</div> 4757 4758<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>pointsize of the PostScript, OPTION1, or TrueType font.</td><td style='text-align:right;'></td></tr></table> 4759 4760<div style="margin: auto;"> 4761 <h4><a id="polaroid"></a>-polaroid <em class="arg">angle</em></h4> 4762</div> 4763 4764<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>simulate a Polaroid picture.</td><td style='text-align:right;'></td></tr></table> 4765 4766<p>Use <kbd>+polaroid</kbd> to rotate the image at a random angle between -15 and +15 degrees.</p> 4767 4768<div style="margin: auto;"> 4769 <h4><a id="posterize"></a>-posterize <em class="arg">levels</em></h4> 4770</div> 4771 4772<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>reduce the image to a limited number of color levels.</td><td style='text-align:right;'></td></tr></table> 4773 4774<div style="margin: auto;"> 4775 <h4><a id="precision"></a>-precision <em class="arg">value</em></h4> 4776</div> 4777 4778<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>set the maximum number of significant digits to be printed.</td><td style='text-align:right;'></td></tr></table> 4779 4780<div style="margin: auto;"> 4781 <h4><a id="preview"></a>-preview <em class="arg">type</em></h4> 4782</div> 4783 4784<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>image preview type.</td><td style='text-align:right;'></td></tr></table> 4785 4786<p>Use this option to affect the preview operation of an image (e.g. <kbd>convert file.png -preview Gamma Preview:gamma.png</kbd>). Choose from these previews:</p> 4787 4788<pre class="text"> 4789 Rotate 4790 Shear 4791 Roll 4792 Hue 4793 Saturation 4794 Brightness 4795 Gamma 4796 Spiff 4797 Dull 4798 Grayscale 4799 Quantize 4800 Despeckle 4801 ReduceNoise 4802 Add Noise 4803 Sharpen 4804 Blur 4805 Threshold 4806 EdgeDetect 4807 Spread 4808 Shade 4809 Raise 4810 Segment 4811 Solarize 4812 Swirl 4813 Implode 4814 Wave 4815 OilPaint 4816 CharcoalDrawing 4817 JPEG 4818</pre> 4819 4820<p>To print a complete list of previews, use the <a href="#list">-list preview</a> option.</p> 4821 4822<p>The default preview is <kbd>JPEG</kbd>.</p> 4823 4824<div style="margin: auto;"> 4825 <h4><a id="print"></a>-print <em class="arg">string</em></h4> 4826</div> 4827 4828<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>interpret string and print to console.</td><td style='text-align:right;'></td></tr></table> 4829 4830<div style="margin: auto;"> 4831 <h4><a id="process"></a>-process <em class="arg">command</em></h4> 4832</div> 4833 4834<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>process the image with a custom image filter.</td><td style='text-align:right;'></td></tr></table> 4835 4836<p>The command arguments has the form <kbd>"module arg1 arg2 arg3 ... argN"</kbd> where <kbd>module</kbd> is the name of the module to invoke (e.g. "Analyze") and arg1 arg2 arg3 ... argN are an arbitrary number of arguments to pass to the process module.</p> 4837 4838<div style="margin: auto;"> 4839 <h4><a id="profile"></a>-profile <em class="arg">filename</em><br/> 4840 +profile <em class="arg">profile_name</em></h4> 4841</div> 4842 4843<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Manage ICM, IPTC, or generic profiles in an image.</td><td style='text-align:right;'></td></tr></table> 4844 4845<p>Using <a href="#profile">-profile</a> <em class="arg">filename</em> adds an ICM (ICC color management), IPTC (newswire information), or a generic profile to the image.</p> 4846 4847<p>Use <a href="#profile">+profile <em class="arg">profile_name</em></a> to remove the indicated profile. ImageMagick uses standard filename globbing, so wildcard expressions may be used to remove more than one profile. Here we remove all profiles from the image except for the XMP profile: <kbd>+profile "!xmp,*"</kbd>. </p> 4848 4849<p>Use <kbd>identify -verbose</kbd> to find out which profiles are in the image file. Use <a href="#strip">-strip</a> to remove all profiles (and comments).</p> 4850 4851<p>To extract a profile, the <a href="#profile">-profile</a> option is not used. Instead, simply write the file to an image format such as <em class="arg">APP1, 8BImageMagick, ICM,</em> or <em class="arg">IPTC</em>.</p> 4852 4853<p>For example, to extract the Exif data (which is stored in JPEG files in the <em class="arg">APP1</em> profile), use.</p> 4854 4855<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert cockatoo.jpg profile.exif</span></p> 4856<p>It is important to note that results may depend on whether or not the original image already has an included profile. Also, keep in mind that <a href="#profile">-profile</a> is an "operator" (as opposed to a "setting") and therefore a conversion is made each time it is encountered, in order, in the command-line. For instance, in the following example, if the original image is CMYK with profile, a CMYK-CMYK-RGB conversion results.</p> 4857 4858<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert CMYK.tif -profile "CMYK.icc" -profile "RGB.icc" RGB.tiff</span></p> 4859<p>Furthermore, since ICC profiles are not necessarily symmetric, extra conversion steps can yield unwanted results. 4860CMYK profiles are often very asymmetric since they involve 3−>4 and 4−>3 channel mapping. 4861</p> 4862 4863<p>The <a href="#profile">-profile</a> option can also be used to inject 4864previously-formatted ancillary chunks into the output PNG file, using 4865the commandline option as shown below or by setting the profile via a 4866programming interface:</p> 4867 4868<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>-profile PNG-chunk-x:<filename></span></p> 4869<p>where <em>x</em> is a location flag and 4870<em class="arg">filename</em> is a file containing the chunk 4871name in the first 4 bytes, then a colon (":"), followed by the chunk data. 4872This encoder will compute the chunk length and CRC, so those must not 4873be included in the file.</p> 4874 4875<p>"x" can be "b" (before PLTE), "m" (middle, i.e., between PLTE and IDAT), 4876or "e" (end, i.e., after IDAT). If you want to write multiple chunks 4877of the same type, then add a short unique string after the "x" to prevent 4878subsequent profiles from overwriting the preceding ones, e.g.,</p> 4879 4880 4881<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>-profile PNG-chunk-b01:file01 -profile PNG-chunk-b02:file02</span></p> 4882<div style="margin: auto;"> 4883 <h4><a id="quality"></a>-quality <em class="arg">value</em></h4> 4884</div> 4885 4886<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>JPEG/MIFF/PNG compression level.</td><td style='text-align:right;'></td></tr></table> 4887 4888<p>For the JPEG and MPEG image formats, quality is 1 (lowest image quality and highest compression) to 100 (best quality but least effective compression). The default is to use the estimate quality of your input image otherwise 92. Use the <a href="#sampling-factor">-sampling-factor</a> option to specify the factors for chroma downsampling.</p> 4889 4890<p>For the MIFF image format, quality/10 is the zlib 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> 4891 4892<p>For the JPEG-2000 image format, quality is mapped using a non-linear equation to the compression ratio required by the Jasper library. This non-linear equation is intended to loosely approximate the quality provided by the JPEG v1 format. The default quality value 100, a request for non-lossy compression. A quality of 75 results in a request for 16:1 compression.</p> 4893 4894<p>For the MNG and PNG image formats, the quality value sets the zlib compression level (quality / 10) and filter-type (quality % 10). For compression level 0, the Huffman-only strategy is used, which is fastest but not necessarily the worst compression. The default PNG compression is 75.</p> 4895 4896<p>If filter-type is 4 or less, the specified filter-type is used for all scanlines:</p> 4897 4898<pre class="text"> 4899 0: none 4900 1: sub 4901 2: up 4902 3: average 4903 4: Paeth 4904</pre> 4905 4906<p>If filter-type is 5, adaptive filtering is used when quality is greater than 50 and the image does not have a color map, otherwise no filtering is used.</p> 4907 4908<p>If filter-type is 6, adaptive filtering with <em class="arg">minimum-sum-of-absolute-values</em> is used.</p> 4909 4910<p>Only if the output is MNG, if filter-type is 7, the LOCO color transformation and adaptive filtering with <em class="arg">minimum-sum-of-absolute-values</em> are used.</p> 4911 4912<p>The quality setting has no effect on the appearance of PNG and MNG images, since the compression is always lossless.</p> 4913 4914<p>For further information, see the <a href="http://www.w3.org/pub/WWW/TR">PNG</a> specification.</p> 4915 4916<div style="margin: auto;"> 4917 <h4><a id="quantize"></a>-quantize <em class="arg">colorspace</em></h4> 4918</div> 4919 4920<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>reduce colors using this colorspace.</td><td style='text-align:right;'></td></tr></table> 4921 4922<p>This setting defines the colorspace used to sort out and reduce the number 4923of colors needed by an image (for later dithering) by operators such as <a 4924href="#colors" >-colors</a>, Note that color reducion also happens 4925automatically when saving images to color-limited image file formats, such as 4926GIF, and PNG8.</p> 4927 4928 4929<div style="margin: auto;"> 4930 <h4><a id="quiet"></a>-quiet</h4> 4931</div> 4932 4933<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>suppress all warning messages. Error messages are still reported.</td><td style='text-align:right;'></td></tr></table> 4934 4935<div style="margin: auto;"> 4936 <h4><a id="radial-blur"></a>-radial-blur <em class="arg">angle</em></h4> 4937</div> 4938 4939<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Blur around the center of the image.</td><td style='text-align:right;'></td></tr></table> 4940 4941<p>Note that this is actually a rotational blur rather than a radial and as 4942such actually mis-named. </p> 4943 4944<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 4945pixels which are outside the image proper are blurred into the final result. 4946</p> 4947 4948 4949<div style="margin: auto;"> 4950 <h4><a id="raise"></a>-raise <em class="arg">thickness</em></h4> 4951</div> 4952 4953<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Lighten or darken image edges.</td><td style='text-align:right;'></td></tr></table> 4954 4955<p>This will create a 3-D effect. Use <a href="#raise">-raise</a> to create a raised effect, otherwise use <a href="#raise">+raise</a>. 4956</p> 4957 4958<p>Unlike the similar <a href="#frame">-frame</a> option, <a href="#raise">-raise</a> does not alter the dimensions of the image.</p> 4959 4960<div style="margin: auto;"> 4961 <h4><a id="random-threshold"></a>-random-threshold <em class="arg">low</em>x<em class="arg">high</em></h4> 4962</div> 4963 4964<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Apply a random threshold to the image.</td><td style='text-align:right;'></td></tr></table> 4965 4966<div style="margin: auto;"> 4967 <h4><a id="red-primary"></a>-red-primary <em class="arg">x,y</em></h4> 4968</div> 4969 4970<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the red chromaticity primary point.</td><td style='text-align:right;'></td></tr></table> 4971 4972<div style="margin: auto;"> 4973 <h4><a id="regard-warnings"></a>-regard-warnings</h4> 4974</div> 4975 4976<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Pay attention to warning messages.</td><td style='text-align:right;'></td></tr></table> 4977 4978<div style="margin: auto;"> 4979 <h4><a id="remap"></a>-remap <em class="arg">filename</em></h4> 4980</div> 4981 4982<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Reduce the number of colors in an image to the colors used by this image.</td><td style='text-align:right;'></td></tr></table> 4983 4984<p>If the <a href="#dither">-dither</a> setting is enabled (the default) then 4985the given colors are dithered over the image as necessary, otherwise the closest 4986color (in RGB colorspace) is selected to replace that pixel in the image. </p> 4987 4988<p>As a side effect of applying a <a href="#remap">-remap</a> of colors across all 4989images in the current image sequence, all the images will have the same color 4990table. That means that when saved to a file format such as GIF, it will use 4991that color table as a single common or global color table, for all the images, 4992without requiring extra local color tables. </p> 4993 4994<p>Use <a href="#remap">+remap</a> to reduce all images in the current image 4995sequence to use a common color map over all the images. This equivalent to 4996appending all the images together (without extra background colors) and color 4997reducing those images using <a href="#colors">-colors</a> with a 256 color 4998limit, then <a href="#remap">-remap</a> those colors over the original list of 4999images. This ensures all the images follow a single color map. </p> 5000 5001<p>If the number of colors over all the images is less than 256, then <a 5002href="#remap">+remap</a> should not perform any color reduction or dithering, as 5003no color changes are needed. In that case, its only effect is to force the use 5004of a global color table. This recommended after using either <a 5005href="#colors">-colors</a> or <a href="#ordered-dither">-ordered-dither</a> to 5006reduce the number of colors in an animated image sequence. </p> 5007 5008<div style="margin: auto;"> 5009 <h4><a id="region"></a>-region <em class="arg">geometry</em></h4> 5010</div> 5011 5012<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set a region in which subsequent operations apply.</td><td style='text-align:right;'></td></tr></table> 5013 5014<p>The <em class="arg">x</em> and <em class="arg">y</em> offsets are treated in the same manner as in <a href="#crop">-crop</a>.</p> 5015 5016<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 5017 5018<div style="margin: auto;"> 5019 <h4><a id="remote"></a>-remote</h4> 5020</div> 5021 5022<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>perform a remote operation.</td><td style='text-align:right;'></td></tr></table> 5023 5024<p>The only command recognized is the name of an image file to load.</p> 5025 5026<p>If you have more than one <a href="/www/display.html">display</a> application running simultaneously, use the <a href="#window"> window</a> option to specify which application to control.</p> 5027 5028<div style="margin: auto;"> 5029 <h4><a id="render"></a>-render</h4> 5030</div> 5031 5032<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>render vector operations.</td><td style='text-align:right;'></td></tr></table> 5033 5034<p>Use <a href="#render">+render</a> to turn off rendering vector operations. This useful when saving the result to vector formats such as MVG or SVG.</p> 5035 5036<div style="margin: auto;"> 5037<h4><a id="repage"></a>-repage <em class="arg">geometry</em></h4> 5038</div> 5039 5040<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Adjust the canvas and offset information of the image.</td><td style='text-align:right;'></td></tr></table> 5041 5042<p>This option is like <a href="#page">-page</a> but acts as an image operator 5043rather than a setting. You can separately set the canvas size or the offset 5044of the image on that canvas by only providing those components. </p> 5045 5046<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 5047 5048<p>If a <kbd>!</kbd> flag is given the offset given is added to the existing 5049offset to move the image relative to its previous position. This useful for 5050animation sequences. </p> 5051 5052<p>A given a canvas size of zero such as '<kbd>0x0</kbd>' forces it to 5053recalculate the canvas size so the image (at its current offset) will appear 5054completely on that canvas (unless it has a negative offset).</p> 5055 5056<p>Use <a href="#repage">+repage</a> to completely remove/reset the virtual 5057canvas meta-data from the images. </p> 5058 5059<p>The <a href="#set">-set</a> '<kbd>page</kbd>' option can be used to 5060directly assign virtual canvas meta-data. </p> 5061 5062 5063<div style="margin: auto;"> 5064 <h4><a id="resample"></a>-resample <em class="arg">horizontal</em>x<em class="arg">vertical</em></h4> 5065</div> 5066 5067<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Resample image to specified horizontal and vertical resolution.</td><td style='text-align:right;'></td></tr></table> 5068 5069<p>Resize the image so that its rendered size remains the same as the original at the specified target resolution. For example, if a 300 DPI image renders at 3 inches by 2 inches on a 300 DPI device, when the image has been resampled to 72 DPI, it will render at 3 inches by 2 inches on a 72 DPI device. Note that only a small number of image formats (e.g. JPEG, PNG, and TIFF) are capable of storing the image resolution. For formats which do not support an image resolution, the original resolution of the image must be specified via <a href="#density">-density</a> on the command line prior to specifying the resample resolution.</p> 5070 5071<p>Note that Photoshop stores and obtains image resolution from a proprietary embedded profile. If this profile exists in the image, then Photoshop will continue to treat the image using its former resolution, ignoring the image resolution specified in the standard file header.</p> 5072 5073<div style="margin: auto;"> 5074 <h4><a id="resize"></a>-resize <em class="arg">geometry</em></h4> 5075</div> 5076 5077<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Resize an image.</td><td style='text-align:right;'></td></tr></table> 5078 5079<p>See <a href="/www/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 ignored, and the <a href="#gravity">-gravity</a> option has no effect.</p> 5080 5081<p>If the <a href="#filter">-filter</a> option precedes the <a href="#resize">-resize</a> option, the image is resized with the specified filter.</p> 5082 5083<p>Many image processing algorithms assume your image is in a linear-light coding. If your image is gamma-corrected, you can remove the nonlinear gamma correction, apply the transform, then restore it like this:</p> 5084 5085<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert portrait.jpg -gamma .45455 -resize 25% -gamma 2.2 \ <br/> -quality 92 passport.jpg</span></p> 5086<div style="margin: auto;"> 5087 <h4><a id="respect-parentheses"></a>-respect-parentheses</h4> 5088</div> 5089 5090<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>settings remain in effect until parenthesis boundary.</td><td style='text-align:right;'></td></tr></table> 5091 5092<div style="margin: auto;"> 5093 <h4><a id="reverse"></a>-reverse</h4> 5094</div> 5095 5096<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Reverse the order of images in the current image list.</td><td style='text-align:right;'></td></tr></table> 5097 5098 5099<div style="margin: auto;"> 5100 <h4><a id="roll"></a>-roll {<em class="arg">+-</em>}<em class="arg">x</em>{<em class="arg">+-</em>}<em class="arg">y</em></h4> 5101</div> 5102 5103<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>roll an image vertically or horizontally by the amount given.</td><td style='text-align:right;'></td></tr></table> 5104 5105<p>A negative <em class="arg">x</em> offset rolls the image left-to-right. A negative <em class="arg">y</em> offset rolls the image top-to-bottom.</p> 5106 5107 5108<div style="margin: auto;"> 5109 <h4><a id="rotate"></a>-rotate <em class="arg">degrees</em>{<em class="arg"><</em>}{<em class="arg">></em>}</h4> 5110</div> 5111 5112<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Apply Paeth image rotation (using shear operations) to the image.</td><td style='text-align:right;'></td></tr></table> 5113 5114<p>Use <kbd>></kbd> to rotate the image only if its width exceeds the height. <kbd><</kbd> rotates the image <em>only</em> if its width is less than the height. For example, if you specify <kbd>-rotate "-90>"</kbd> and the image size is 480x640, the image is not rotated. However, if the image is 640x480, it is rotated by -90 degrees. If you use <kbd>></kbd> or <kbd><</kbd>, enclose it in quotation marks to prevent it from being misinterpreted as a file redirection.</p> 5115 5116<p>Empty triangles in the corners, left over from rotating the image, are 5117filled with the <kbd>background</kbd> color. </p> 5118 5119<p>See also the <a href="#distort">-distort</a> operator and specifically the 5120'<kbd>ScaleRotateTranslate</kbd>' distort method. </p> 5121 5122 5123<div style="margin: auto;"> 5124 <h4><a id="sample"></a>-sample <em class="arg">geometry</em></h4> 5125</div> 5126 5127<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>minify/magnify the image using pixel subsampling and pixel replication, respectively.</td><td style='text-align:right;'></td></tr></table> 5128 5129<p>Change the image size simply by directly sampling the pixels original 5130image. When magnifying, pixels are replicated in blocks. When minifying, 5131pixels are sub-sampled (i.e., some rows and columns are skipped over). </p> 5132 5133<p>The results are thus equivalent to using <a href="#resize">-resize</a> with 5134a <a href="#filter">-filter</a> setting of <kbd>point</kbd> (nearest 5135neighbour), though <a href="#sample">-sample</a> is a lot faster, as it 5136avoids all the filter processing of the image. As such it completely ignores 5137the current <a href="#filter">-filter</a> setting. </p> 5138 5139<p>The key feature of the <a href="#sample">-sample</a> is that no new colors 5140will be added to the resulting image, though some colors may disappear. </p> 5141 5142<p>See <a href="/www/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 5143ignored, unlike <a href="#resize">-resize</a>. </p> 5144 5145 5146<div style="margin: auto;"> 5147 <h4><a id="sampling-factor"></a>-sampling-factor <em class="arg">horizontal-factor</em>x<em class="arg">vertical-factor</em></h4> 5148</div> 5149 5150<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>sampling factors used by JPEG or MPEG-2 encoder and YUV decoder/encoder.</td><td style='text-align:right;'></td></tr></table> 5151 5152<p>This option specifies the sampling factors to be used by the JPEG encoder for chroma downsampling. If this option is omitted, the JPEG library will use its own default values. When reading or writing the YUV format and when writing the M2V (MPEG-2) format, use <a href="#sampling-factor">-sampling-factor 2x1</a> or <a href="#sampling-factor">-sampling-factor 4:2:2</a> to specify the 4:2:2 downsampling method.</p> 5153 5154<div style="margin: auto;"> 5155 <h4><a id="scale"></a>-scale <em class="arg">geometry</em></h4> 5156</div> 5157 5158<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>minify/magnify the image using pixel block averaging and pixel replication, respectively.</td><td style='text-align:right;'></td></tr></table> 5159 5160<p>Change the image size simply by replacing pixels by averaging pixels 5161together when minifying, or replacing pixels when magnifing. </p> 5162 5163<p>The results are thus equivalent to using <a href="#resize">-resize</a> with 5164a <a href="#filter">-filter</a> setting of <kbd>box</kbd>. Though it is a lot 5165faster, as it avoids all the filter processing of the image. As such it 5166completely ignores the current <a href="#filter">-filter</a> setting. </p> 5167 5168<p>If when shrinking (minifying) images the original image is some integer 5169multiple of the new image size, the number of pixels avergaed together to 5170produce the new pixel color is the same across the whole image. This is 5171a special case known as 'binning' and is often used as a method of reducing 5172noise in image such as those generated by digital cameras, especially in low 5173light conditions. </p> 5174 5175 5176<div style="margin: auto;"> 5177 <h4><a id="scene"></a>-scene <em class="arg">value</em></h4> 5178</div> 5179 5180<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>set scene number.</td><td style='text-align:right;'></td></tr></table> 5181 5182<p>This option sets the scene number of an image or the first image in an image sequence.</p> 5183 5184<div style="margin: auto;"> 5185 <h4><a id="screen"></a>-screen</h4> 5186</div> 5187 5188<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>specify the screen to capture.</td><td style='text-align:right;'></td></tr></table> 5189 5190<p>This option indicates that the GetImage request used to obtain the image should be done on the root window, rather than directly on the specified window. In this way, you can obtain pieces of other windows that overlap the specified window, and more importantly, you can capture menus or other popups that are independent windows but appear over the specified window.</p> 5191 5192<div style="margin: auto;"> 5193 <h4><a id="seed"></a>-seed</h4> 5194</div> 5195 5196<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>seed a new sequence of pseudo-random numbers</td><td style='text-align:right;'></td></tr></table> 5197 5198<div style="margin: auto;"> 5199 <h4><a id="segment"></a>-segment <em class="arg">cluster-threshold</em>x<em class="arg">smoothing-threshold</em></h4> 5200</div> 5201 5202<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>segment the colors of an image.</td><td style='text-align:right;'></td></tr></table> 5203 5204<p>Segment an image by analyzing the histograms of the color components and identifying units that are homogeneous with the fuzzy c-means technique. This is part of the ImageMagick color quantization routines. </p> 5205 5206<p>Specify <em class="arg">cluster threshold</em> as the number of pixels in each cluster that must exceed the cluster threshold to be considered valid. <em class="arg">Smoothing threshold</em> eliminates noise in the second derivative of the histogram. As the value is increased, you can expect a smoother second derivative. The default is 1.5.</p> 5207 5208<p>If the <a href="#verbose">-verbose</a> setting is defined, a detailed report 5209of the color clusters is returned.</p> 5210 5211 5212<div style="margin: auto;"> 5213 <h4><a id="selective-blur"></a>-selective-blur <em class="arg">radius</em><br />-selective-blur <em class="arg">radius</em>x<em class="arg">sigma</em>{<em class="arg">+threshold</em>}</h4> 5214</div> 5215 5216<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Selectively blur pixels within a contrast threshold.</td><td style='text-align:right;'></td></tr></table> 5217 5218<p>Blurs those pixels that are less than or equal to the threshold in contrast. The threshold may be expressed as a fraction of <em class="QR">QuantumRange</em> or as a percentage.</p> 5219 5220<div style="margin: auto;"> 5221 <h4><a id="separate"></a>-separate</h4> 5222</div> 5223 5224<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>separate an image channel into a grayscale image. Specify the channel with <a href="#channel">-channel</a>.</td><td style='text-align:right;'></td></tr></table> 5225 5226<div style="margin: auto;"> 5227 <h4><a id="sepia-tone"></a>-sepia-tone <em class="arg">threshold</em></h4> 5228</div> 5229 5230<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>simulate a sepia-toned photo.</td><td style='text-align:right;'></td></tr></table> 5231 5232<p>Specify <em class="arg">threshold</em> as the percent threshold of the intensity (0 - 99.9%).</p> 5233 5234<p>This option applies a special effect to the image, similar to the effect achieved in a photo darkroom by sepia toning. Threshold ranges from 0 to <em class="QR">QuantumRange</em> and is a measure of the extent of the sepia toning. A threshold of 80% is a good starting point for a reasonable tone.</p> 5235 5236 5237 5238<div style="margin: auto;"> 5239 <h4><a id="set"></a>-set <em class="arg">key value</em></h4> 5240 <h4>+set <em class="arg">key</em></h4> 5241</div> 5242 5243<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>sets image attributes and properties for images in the current 5244image sequence.</td><td style='text-align:right;'></td></tr></table> 5245 5246<p>This will assign (or modify) specific settings attached to all the images 5247in the current image sequence. Using the <a href="#set">+set</a> form of the 5248option will either remove, or reset that setting to a default state, as 5249appropriate. </p> 5250 5251<p>For example, it will modify specific well known image meta-data 5252'attributes' such as those normally overridden by: the options <a 5253href="#delay" >-delay</a>, <a href="#dispose" >-dispose</a>, and <a 5254href="#page" >-page</a>, <a href="#colorspace" >-colorspace</a>; generally 5255assigned before the image is read in, by using a <em class="arg">key</em> of 5256the same name. </p> 5257 5258<p>If the given <em class="arg">key</em> does not match a specific known 5259'attribute ', such as shown above, the setting is stored as a a free form 5260'property' string. Such settings are listed in <a href="#verbose" 5261>-verbose</a> information ("<kbd>info:</kbd>" output format) as "Properties". 5262</p> 5263 5264<p>This includes string 'properities' that are set by and assigned to images 5265using the options <a href="#comment" >-comment</a>, <a href="#label" 5266>-label</a>, <a href="#caption" >-caption</a>. These options actually assign 5267a global 'artifact' which are automatically assigned (and any <a href="/www/escape.html" >Format Percent 5268Escapes</a> expanded) to images as they are read in. For example:</p> 5269 5270<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -set comment 'Rose is a rose is a rose is a rose' rose.png</span><span class='crtout'>identify -format %c rose.png</span><span class="crtprompt"> $magick> </span><span class='crtin'>Rose is a rose is a rose is a rose</span></p> 5271<p>The set value can also make use of <a href="/www/escape.html" >Format and Print Image 5272Properties</a> in the defined value. For example:</p> 5273 5274<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -set origsize '%wx%h' -resize 50% \</span><span class='crtout'> -format 'Old size = %[origsize] New size = %wx%h' info:</span><span class="crtprompt"> $magick> </span><span class='crtin'>Old size = 70x46 New size = 35x23</span></p> 5275<p>Other well known 'properities' that can be include: 5276'<kbd>date:create</kbd>' and '<kbd>date:modify</kbd>' and 5277'<kbd>signature</kbd>'. </p> 5278 5279<p>The <a href="#repage">-repage</a> operator will also allow you to modify 5280the '<kbd>page</kbd>' attribute of an image for images already in memory (also 5281see <a href="#repage">-page</a>). However it is designed to provide a finer 5282control of the sub-parts of this 'attribute'. The <a href="#set">-set page</a> 5283option will only provide a direct, unmodified assignment of '<kbd>page</kbd>' 5284attribute. </p> 5285 5286<p>This option can also associate a colorspace or profile with your image. 5287For example,</p> 5288 5289<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.psd -set profile ISOcoated_v2_eci.icc image-icc.psd</span></p> 5290<p>Some 'properties' must be defined in a specific way to be used. For 5291example only 'properties' prefixed with "<kbd>filename:</kbd>" can be used to 5292modify the output filename of an image. For example</p> 5293 5294<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -set filename:mysize '%wx%h' 'rose_%[filename:mysize].png'</span></p> 5295<p>If the setting value is prefixed with "<kbd>option:</kbd>" the setting will 5296be saved as a global "Artifact" exactly as if it was set using the <a 5297href="#define" >-define</a> option. As such settings are globel in scope, they 5298can be used to pass 'attributes' and 'properities' of one specific image, 5299in a way that allows you to use them in a completely different image, even if 5300the original image has long since been modified or destroyed. For example: </p> 5301 5302<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -set option:rosesize '%wx%h' -delete 0 \</span><span class='crtout'> label:'%[rosesize]' label_size_of_rose.gif</span></p> 5303<p>Note that <a href="/www/escape.html" >Format Percent Escapes</a> will only match 5304a 'artifact' if the given <em class="arg">key</em> does not match an existing 5305'attribute' or 'property'. </p> 5306 5307<p>You can set the attributes of the image registry by prefixing the value 5308with <kbd>registry:</kbd>.</p> 5309 5310 5311 5312<div style="margin: auto;"> 5313 <h4><a id="shade"></a>-shade <em class="arg">azimuth</em>x<em class="arg">elevation</em></h4> 5314</div> 5315 5316<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>shade the image using a distant light source.</td><td style='text-align:right;'></td></tr></table> 5317 5318<p>Specify <em class="arg">azimuth</em> and <em class="arg">elevation</em> as the position of the light source. Use <a href="#shade">+shade</a> to return the shading results as a grayscale image.</p> 5319 5320<div style="margin: auto;"> 5321 <h4><a id="shadow"></a>-shadow <em class="arg">percent-opacity</em>{x<em class="arg">sigma</em>}{<em class="arg">+-</em>}<em class="arg">x</em>{<em class="arg">+-</em>}<em class="arg">y</em>{<em class="arg">%</em>}</h4> 5322</div> 5323 5324<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>simulate an image shadow.</td><td style='text-align:right;'></td></tr></table> 5325 5326<div style="margin: auto;"> 5327 <h4><a 5328id="shared-memory"></a>-shared-memory</h4> 5329</div> 5330 5331<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>use shared memory.</td><td style='text-align:right;'></td></tr></table> 5332 5333<p>This option specifies whether the utility should attempt to use shared memory for pixmaps. ImageMagick must be compiled with shared memory support, and the display must support the <em class="arg">MIT-SHM</em> extension. Otherwise, this option is ignored. The default is <kbd>True</kbd>.</p> 5334 5335<div style="margin: auto;"> 5336 <h4><a id="sharpen"></a>-sharpen <em class="arg">radius</em>{x<em class="arg">sigma</em>}</h4> 5337</div> 5338 5339<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>sharpen the image.</td><td style='text-align:right;'></td></tr></table> 5340 5341<p>Use a Gaussian operator of the given radius and standard deviation (sigma).</p> 5342 5343<div style="margin: auto;"> 5344 <h4><a id="shave"></a>-shave <em class="arg">geometry</em></h4> 5345</div> 5346 5347<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Shave pixels from the image edges.</td><td style='text-align:right;'></td></tr></table> 5348 5349<p>The <em class="arg">size</em> portion of the <em class="arg">geometry</em> argument specifies the width of the region to be removed from both sides of the image and the height of the regions to be removed from top and bottom. Offsets are ignored.</p> 5350 5351<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 5352 5353<div style="margin: auto;"> 5354 <h4><a id="shear"></a>-shear <em class="arg">Xdegrees</em>[x<em class="arg">Ydegrees</em>]</h4> 5355</div> 5356 5357<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Shear the image along the x-axis and/or y-axis.</td><td style='text-align:right;'></td></tr></table> 5358 5359<p>The shear angles may be positive, negative, or zero. When <em class="arg">Ydegrees</em> is omitted it defaults to 0. When both angles are given, the horizontal component of the shear is performed before the vertical component.</p> 5360 5361<p>Shearing slides one edge of an image along the x-axis or y-axis (i.e., horizontally or vertically, respectively),creating a parallelogram. The amount of each is controlled by the respective shear angle. For horizontal shears, <em class="arg">Xdegrees</em> is measured clockwise relative to "up" (the negative y-axis), sliding the top edge to the right when 0°<<em class="arg">Xdegrees</em><90° and to the left when 90°<<em class="arg">Xdegrees</em><180°. For vertical shears <em class="arg">Ydegrees</em> is measured clockwise relative to "right" (the positive x-axis), sliding the right edge down when 0°<<em class="arg">Ydegrees</em><90° and up when 90°<<em class="arg">Ydegrees</em><180°.</p> 5362 5363<p>Empty triangles left over from shearing the image are filled with the color defined by the <a href="#fill">-background</a> option. The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 5364 5365<p>The horizontal shear is performed before the vertical part. This is important to note, since horizontal and vertical shears do not <em>commute</em>, i.e., the order matters in a sequence of shears. For example, the following two commands are not equivalent.</p> 5366 5367<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert logo: -shear 20x0 -shear 0x60 logo-sheared.png</span><span class='crtout'></span><span class="crtprompt"> $magick> </span><span class='crtin'>convert logo: -shear 0x60 -shear 20x0 logo-sheared.png</span></p> 5368<p>The first of the two commands above is equivalent to the following, except for the amount of empty space created; the command that follows generates a smaller image, and so is a better choice in terms of time and space.</p> 5369 5370<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert logo: -shear 20x60 logo-sheared.png</span></p> 5371<div style="margin: auto;"> 5372 <h4><a id="sigmoidal-contrast"></a>-sigmoidal-contrast <em class="arg">contrast</em>x<em class="arg">mid-point</em></h4> 5373</div> 5374 5375<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>increase the contrast without saturating highlights or shadows.</td><td style='text-align:right;'></td></tr></table> 5376 5377<p>Increase the contrast of the image using a sigmoidal transfer function without saturating highlights or shadows. <em class="arg">Contrast</em> indicates how much to increase the contrast (0 is none; 3 is typical; 20 is a lot); <em class="arg">mid-point</em> indicates where midtones fall in the resultant image (0 is white; 50% is middle-gray; 100% is black). By default the image contrast is increased, use <em class="arg">+sigmoidal-contrast</em> to decrease the contrast.</p> 5378 5379<div style="margin: auto;"> 5380 <h4><a id="silent"></a>-silent</h4> 5381</div> 5382 5383<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>operate silently.</td><td style='text-align:right;'></td></tr></table> 5384 5385<div style="margin: auto;"> 5386 <h4><a id="size"></a>-size <em class="arg">width</em>[x<em class="arg">height</em>][<em class="arg">+offset</em>]</h4> 5387</div> 5388 5389<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>set the width and height of the image.</td><td style='text-align:right;'></td></tr></table> 5390 5391<p>Use this option to specify the width and height of raw images whose dimensions are unknown such as <kbd>GRAY</kbd>, <kbd>RGB</kbd>, or <kbd>CMYK</kbd>. In addition to width and height, use <a href="#size">-size</a> with an offset to skip any header information in the image or tell the number of colors in a <kbd>MAP</kbd> image file, (e.g. -size 640x512+256).</p> 5392 5393<p>For Photo CD images, choose from these sizes:</p> 5394 5395<pre class="text"> 5396 192x128 5397 384x256 5398 768x512 5399 1536x1024 5400 3072x2048 5401</pre> 5402 5403<div style="margin: auto;"> 5404 <h4><a id="sketch"></a>-sketch <em class="arg">radius</em><br />-sketch <em class="arg">radius</em>x<em class="arg">sigma</em>+<em class="arg">angle</em></h4> 5405</div> 5406 5407<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>simulate a pencil sketch.</td><td style='text-align:right;'></td></tr></table> 5408 5409<p>Sketch with the given radius, standard deviation (sigma), and angle. The angle given is the angle toward which the image is sketched. That is the direction people would consider the object is coming from. </p> 5410 5411<div style="margin: auto;"> 5412 <h4><a id="smush"></a>-smush <em class="arg">offset</em></h4> 5413</div> 5414 5415<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>smush an image sequence together.</td><td style='text-align:right;'></td></tr></table> 5416 5417<div style="margin: auto;"> 5418 <h4><a id="snaps"></a>-snaps <em class="arg">value</em></h4> 5419</div> 5420 5421<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the number of screen snapshots.</td><td style='text-align:right;'>[<a href="/www/import.html">import</a>]</td></tr></table> 5422 5423<p>Use this option to grab more than one image from the X server screen, to create an animation sequence.</p> 5424 5425<div style="margin: auto;"> 5426 <h4><a id="solarize"></a>-solarize <em class="arg">threshold</em></h4> 5427</div> 5428 5429<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>negate all pixels above the threshold level.</td><td style='text-align:right;'></td></tr></table> 5430 5431<p>Specify <em class="arg">factor</em> as the percent threshold of the intensity (0 - 99.9%).</p> 5432 5433<p>This option produces a <em class="arg">solarization</em> effect seen when exposing a photographic film to light during the development process.</p> 5434 5435<div style="margin: auto;"> 5436 <h4><a id="sparse-color"></a>-sparse-color <em 5437 class="arg">method</em> '<em class="arg">x</em>,<em class="arg">y</em> <em class="arg">color</em> ...'</h4> 5438</div> 5439 5440<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'> color the given image using the specified points of color, and filling the other intervening colors using the given methods. </td><td style='text-align:right;'></td></tr></table> 5441 5442 5443<table class="doc"> 5444 <tbody> 5445 <tr valign="top"> 5446 <th align="left" style="width: 8%">Method</th> 5447 <th align="left">Description</th> 5448 </tr> 5449 5450 <tr valign="top"> 5451 <td valign="top">voronoi</td> 5452 <td valign="top">Simply map each pixel to the to nearest color point 5453 given. The result are polygonal 'cells' of solid color. </td> 5454 </tr> 5455 5456 <tr valign="top"> 5457 <td valign="top">shepards</td> 5458 <td valign="top">Colors points biased on the ratio of inverse distance 5459 squared. Generating spots of color in a sea of the average of 5460 colors. </td> 5461 </tr> 5462 5463 <tr valign="top"> 5464 <td valign="top">barycentric</td> 5465 <td valign="top">three point triangle of color given 3 points. 5466 Giving only 2 points will form a linear gradient between those points. 5467 Gradient is however not restricted to just the triangle or line. </td> 5468 </tr> 5469 5470 <tr valign="top"> 5471 <td valign="top">bilinear</td> 5472 <td valign="top">Like barycentric but for 4 points. Less than 4 points 5473 fall back to barycentric. </td> 5474 </tr> 5475 5476 </tbody> 5477</table> 5478 5479<p>The points are placed according to the images location on the virtual 5480canvas (<a href="#page" >-page</a> or <a href="#repage" >-repage</a> 5481offset), and do not actually have to exist on the given image, but may be 5482some point beyond the edge of the image. All points are floating point values. 5483</p> 5484 5485<p>Only the color channels defined by the <a href="#channel" >-channel</a> are 5486modified, whcih means the matte/alpha transparency channel is not effected by 5487default. If enabled, the image also needs a the matte/alpha channel to be 5488enabled for this operator to effect an images transparency. This is typical 5489transparency handling for images. </p> 5490 5491<p>All the above methods when given a single point of color will replace all 5492the colors in the image with the color given, regardless of the point. This is 5493logical, and provides an alternative technique to recolor a image to some 5494default value. </p> 5495 5496 5497<div style="margin: auto;"> 5498 <h4><a id="splice"></a>-splice <em class="arg">geometry</em></h4> 5499</div> 5500 5501<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Splice the current background color into the image.</td><td style='text-align:right;'></td></tr></table> 5502 5503<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. See <a href="#background">-background</a> to reset the background color.</p> 5504 5505<div style="margin: auto;"> 5506 <h4><a id="spread"></a>-spread <em class="arg">amount</em></h4> 5507</div> 5508 5509<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>displace image pixels by a random amount.</td><td style='text-align:right;'></td></tr></table> 5510 5511<p>The argument <em class="arg">amount</em> defines the size of the neighborhood around each pixel from which to choose a candidate pixel to swap.</p> 5512 5513<div style="margin: auto;"> 5514 <h4><a id="statistic"></a>-statistic <em class="arg">type</em> <em class="arg">geometry</em></h4> 5515</div> 5516 5517<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>replace each pixel with corresponding statistic from the neighborhood.</td><td style='text-align:right;'>[<a href="/www/convert.html">convert</a>, <a href="/www/mogrify.html">mogrify</a>]</td></tr></table> 5518 5519<p>Choose from these statistic types:</p> 5520<pre class="text"> 5521 Maximum 5522 Minimum 5523 Mean 5524 Median 5525 Mode 5526 Nonpeak 5527</pre> 5528 5529<div style="margin: auto;"> 5530 <h4><a id="stegano"></a>-stegano <em class="arg">offset</em></h4> 5531</div> 5532 5533<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>hide watermark within an image.</td><td style='text-align:right;'></td></tr></table> 5534 5535<p>Use an offset to start the image hiding some number of pixels from the beginning of the image. Note this offset and the image size. You will need this information to recover the steganographic image (e.g. display -size 320x256+35 stegano:image.png).</p> 5536 5537<div style="margin: auto;"> 5538 <h4><a id="stereo"></a>-stereo <em class="arg">+x</em>{<em class="arg">+y</em>}</h4> 5539</div> 5540 5541<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>composite two images to create a stereo anaglyph.</td><td style='text-align:right;'>[<a href="/www/composite.html">composite</a>]</td></tr></table> 5542 5543<p>The left side of the stereo pair is saved as the red channel of the output image. The right side is saved as the green channel. Red-green stereo glasses are required to properly view the stereo image.</p> 5544 5545<div style="margin: auto;"> 5546 <h4><a id="storage-type"></a>-storage-type <em class="arg">type</em></h4> 5547</div> 5548 5549<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>pixel storage type. Here are the valid types:</td><td style='text-align:right;'></td></tr></table> 5550 5551<pre class="text"> 5552 char store pixels as unsigned characters 5553 double store pixels as doubles 5554 float store pixels as floats 5555 integer store pixels as integers 5556 long store pixels as longs 5557 quantum store pixels in the native depth of your ImageMagick distribution 5558 short store pixels as unsigned shorts 5559</pre> 5560 5561<p>Float and double types are normalized from 0.0 to 1.0 otherwise the pixels 5562values range from 0 to the maximum value the storage type can support.</p> 5563 5564<div style="margin: auto;"> 5565 <h4><a id="stretch"></a>-stretch <em class="arg">fontStretch</em></h4> 5566</div> 5567 5568<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set a type of stretch style for fonts.</td><td style='text-align:right;'></td></tr></table> 5569 5570<p>This setting suggests a type of stretch that ImageMagick should try to apply to the currently selected font family. Select <em class="arg">fontStretch</em> from the following.</p> 5571 5572<pre class="text"> 5573 Any 5574 Condensed 5575 Expanded 5576 ExtraCondensed 5577 ExtraExpanded 5578 Normal 5579 SemiCondensed 5580 SemiExpanded 5581 UltraCondensed 5582 UltraExpanded 5583</pre> 5584 5585<p>To print a complete list of stretch types, use <a href="#list">-list stretch</a>.</p> 5586 5587<p>For other settings that affect fonts, see the options <a href="#font">-font</a>, <a href="#family">-family</a>, <a href="#style">-style</a>, and <a href="#weight">-weight</a>. </p> 5588 5589<div style="margin: auto;"> 5590 <h4><a id="strip"></a>-strip</h4> 5591</div> 5592 5593<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>strip the image of any profiles or comments.</td><td style='text-align:right;'></td></tr></table> 5594 5595<div style="margin: auto;"> 5596 <h4><a id="stroke"></a>-stroke <em class="arg">color</em></h4> 5597</div> 5598 5599<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>color to use when stroking a graphic primitive.</td><td style='text-align:right;'></td></tr></table> 5600 5601<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 5602 5603<p>See <a href="#draw">-draw</a> for further details.</p> 5604 5605<div style="margin: auto;"> 5606 <h4><a id="strokewidth"></a>-strokewidth <em class="arg">value</em></h4> 5607</div> 5608 5609<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>set the stroke width.</td><td style='text-align:right;'></td></tr></table> 5610 5611<p>See <a href="#draw">-draw</a> for further details.</p> 5612 5613<div style="margin: auto;"> 5614 <h4><a id="style"></a>-style <em class="arg">fontStyle</em></h4> 5615</div> 5616 5617<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set a font style for text.</td><td style='text-align:right;'></td></tr></table> 5618 5619<p>This setting suggests a font style that ImageMagick should try to apply to 5620the currently selected font family. Select <em class="arg">fontStyle</em> from 5621the following.</p> 5622 5623<pre class="text"> 5624 Any 5625 Italic 5626 Normal 5627 Oblique 5628</pre> 5629 5630<p>For other settings that affect fonts, see the options <a href="#font">-font</a>, <a href="#family">-family</a>, <a href="#stretch">-stretch</a>, and <a href="#weight">-weight</a>. </p> 5631 5632<div style="margin: auto;"> 5633 <h4><a id="subimage-search"></a>-subimage-search</h4> 5634</div> 5635 5636<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>search for subimage.</td><td style='text-align:right;'>[<a href="/www/compare.html">compare</a>]</td></tr></table> 5637 5638<p>This option is required to have compare search for the best match location 5639of a small image within a larger image. This search will produce two images 5640(or two frames). The first is the "difference" image and the second will 5641be the "match score" image.</p> 5642 5643<p>The "match-score" image is smaller containing a pixel for ever possible 5644position of the top-left corner of the given sub-image. that is its size will 5645be the size of the larger_image - sub_image + 1. The brightest location in 5646this image is the location s the locate on the best match that is also 5647reported. Note that this may or may nor be a perfect match, and the actual 5648brightness will reflect this. Other bright 'peaks' can be used to locate other 5649possible matching loctions. </p> 5650 5651<p>Note that the search will try to compare teh sub-image at every possible 5652location in the larger image, as such it can be very slow. The smaller the 5653sub-image the faster this search is. </p> 5654 5655 5656<div style="margin: auto;"> 5657 <h4><a id="swap"></a>-swap <em class="arg">index,index</em></h4> 5658</div> 5659 5660<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Swap the positions of two images in the image sequence.</td><td style='text-align:right;'></td></tr></table> 5661 5662<p>For example, <a href="#swap">-swap 0,2</a> swaps the first and the third 5663images in the current image sequence. Use <a href="#swap">+swap</a> to switch 5664the last two images in the sequence.</p> 5665 5666<div style="margin: auto;"> 5667 <h4><a id="swirl"></a>-swirl <em class="arg">degrees</em></h4> 5668</div> 5669 5670<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>swirl image pixels about the center.</td><td style='text-align:right;'></td></tr></table> 5671 5672<p><em class="arg">Degrees</em> defines the tightness of the swirl.</p> 5673 5674<div style="margin: auto;"> 5675 <h4><a id="synchronize"></a>-synchronize</h4> 5676</div> 5677 5678<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>synchronize image to storage device.</td><td style='text-align:right;'></td></tr></table> 5679 5680<div style="margin: auto;"> 5681 <h4><a id="taint"></a>-taint</h4> 5682</div> 5683 5684<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Mark the image as modified.</td><td style='text-align:right;'></td></tr></table> 5685 5686<div style="margin: auto;"> 5687 <h4><a id="text-font"></a>-text-font <em class="arg">name</em></h4> 5688</div> 5689 5690<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>font for writing fixed-width text.</td><td style='text-align:right;'></td></tr></table> 5691 5692<p>Specifies the name of the preferred font to use in fixed (typewriter style) formatted text. The default is 14 point <em class="arg">Courier</em>.</p> 5693 5694<p>You can tag a font to specify whether it is a PostScript, TrueType, or OPTION1 font. For example, <kbd>Courier.ttf</kbd> is a TrueType font and <kbd>x:fixed</kbd> is OPTION1.</p> 5695 5696<div style="margin: auto;"> 5697 <h4><a id="texture"></a>-texture <em class="arg">filename</em></h4> 5698</div> 5699 5700<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>name of texture to tile onto the image background.</td><td style='text-align:right;'></td></tr></table> 5701 5702<div style="margin: auto;"> 5703 <h4><a id="threshold"></a>-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 5704</div> 5705 5706<!-- {<em class="arg">green,blue,opacity</em>} 5707<p>If the green or blue value is omitted, these channels use the same value as the first one provided. If all three color values are the same, the result is a bi-level image. If the opacity threshold is omitted, OpaqueOpacity is used and any partially transparent pixel becomes fully transparent.</p> 5708--> 5709 5710<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Apply simultaneous black/white threshold to the image.</td><td style='text-align:right;'></td></tr></table> 5711 5712<p>Any pixel values (more specifically, those channels set using <a href="/www/command-line-options.html#channel">‑channel</a>) that exceed the specified threshold are reassigned the maximum channel value, while all other values are assigned the minimum.</p> 5713 5714<p> The threshold value can be given as a percentage or as an absolute integer value corresponding to the desired channel value. When given as an integer, the minimum attainable value is 0 (corresponding to black when all channels are affected), but the maximum value (corresponding to white) is that of the <kbd>quantum depth</kbd> of the particular build of ImageMagick, and is therefore dependent on the installation. For that reason, a reasonable recommendation for most applications is to specify the threshold values as a percentage. 5715</p> 5716 5717<p> The following would force pixels with red values above 50% to have 100% red values, while those at or below 50% red would be set to 0 in the red channel. The green, blue, and alpha channels (if present) would be unchanged. </p> 5718 5719<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert in.png -channel red -threshold 50% out.png</span></p> 5720<p>As (possibly) impractical but instructive examples, the following would generate an all-black and an all-white image with the same dimensions as the input image.</p> 5721 5722 5723<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert in.png -threshold 100% black.png</span><span class='crtout'></span><span class="crtprompt"> $magick> </span><span class='crtin'>convert in.png -threshold -1 white.png</span></p> 5724<p>Note that the values of the transparency channel is treated as 'matte' 5725values (0 is opaque) and not as 'alpha' values (0 is transparent).</p> 5726 5727<p> See also <a href="/www/command-line-options.html#black-threshold">‑black‑threshold</a> and <a href="/www/command-line-options.html#white-threshold">‑white‑threshold</a>. 5728</p> 5729 5730<div style="margin: auto;"> 5731 <h4><a id="thumbnail"></a>-thumbnail <em class="arg">geometry</em></h4> 5732</div> 5733 5734<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Create a thumbnail of the image.</td><td style='text-align:right;'></td></tr></table> 5735 5736<p>This is similar to <a href="#resize">-resize</a>, except it is optimized for speed and any image profile, other than a color profile, is removed to reduce the thumbnail size. To strip the color profiles as well, add <a href="#strip">-strip</a> just before of after this option.</p> 5737 5738<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 5739 5740<div style="margin: auto;"> 5741 <h4><a id="tile"></a>-tile <em class="arg">filename</em></h4> 5742</div> 5743 5744<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the tile image used for filling a subsequent graphic primitive.</td><td style='text-align:right;'></td></tr></table> 5745 5746<div style="margin: auto;"> 5747 <h4>-tile <em class="arg">geometry</em></h4> 5748</div> 5749 5750<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specify the layout of images .</td><td style='text-align:right;'>[<a href="/www/montage.html">montage</a>]</td></tr></table> 5751 5752<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 5753 5754<div style="margin: auto;"> 5755 <h4>-tile</h4> 5756</div> 5757 5758<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specifies that a subsequent composite operation is repeated across and down image.</td><td style='text-align:right;'>[<a href="/www/composite.html">composite</a>]</td></tr></table> 5759 5760<div style="margin: auto;"> 5761 <h4><a id="tile-offset"></a>-tile-offset {<em class="arg">+-</em>}<em class="arg">x</em>{<em class="arg">+-</em>}<em class="arg">y</em></h4> 5762</div> 5763 5764<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specify the offset for tile images, relative to the background image it is tiled on.</td><td style='text-align:right;'></td></tr></table> 5765 5766<p>This should be set before the tiling image is set by <a href="#tile" >-tile</a> or <a href="#texture" >-texture</a>, or directly applied for creating a tiled canvas using <kbd>TILE:</kbd> or <kbd>PATTERN:</kbd> input formats. </p> 5767 5768<p>Internally ImageMagick does a <a href="#roll" >-roll</a> of the tile image by the arguments given when the tile image is set. </p> 5769 5770<div style="margin: auto;"> 5771 <h4><a id="tint"></a>-tint <em class="arg">value</em></h4> 5772</div> 5773 5774<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Tint the image with the fill color.</td><td style='text-align:right;'></td></tr></table> 5775 5776<p>Tint the image with the fill color.</p> 5777 5778<p>Specify the amount of tinting as a percentage. Pure colors like black, white red, yellow, will not be affected by -tint. Only mid-range colors such as the various shades of grey.</p> 5779 5780<div style="margin: auto;"> 5781 <h4><a id="title"></a>-title <em class="arg">string</em></h4> 5782</div> 5783 5784<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Assign a title to displayed image.</td><td style='text-align:right;'>[<a href="/www/animate.html">animate</a>, <a href="/www/display.html">display</a>, <a href="/www/montage.html">montage</a>]</td></tr></table> 5785 5786<p>Use this option to assign a specific title to the image. This assigned to the image window and is typically displayed in the window title bar. Optionally you can include the image filename, type, width, height, Exif data, or other image attribute by embedding special format characters described under the <a href="#format">-format</a> option.</p> 5787 5788<p>For example,</p> 5789 5790<p class="crtsnip"> 5791 -title "%m:%f %wx%h" 5792</p> 5793 5794<p>produces an image title of <kbd>MIFF:bird.miff 512x480</kbd> for an image titled <kbd>bird.miff</kbd> and whose width is 512 and height is 480.</p> 5795 5796 5797<div style="margin: auto;"> 5798 <h4><a id="transform"></a>-transform</h4> 5799</div> 5800 5801<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>transform the image.</td><td style='text-align:right;'></td></tr></table> 5802 5803<p>This option applies the transformation matrix from a previous <a href="#affine">-affine</a> option.</p> 5804 5805<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -affine 2,2,-2,2,0,0 -transform bird.ppm bird.jpg</span></p> 5806 5807<p>This operator has been now been superseded by the <a 5808href="#distort">-distort</a> '<kbd>AffineProjection</kbd>' method. </p> 5809 5810 5811<div style="margin: auto;"> 5812 <h4><a id="transparent"></a>-transparent <em class="arg">color</em></h4> 5813</div> 5814 5815<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Make this color transparent within the image.</td><td style='text-align:right;'></td></tr></table> 5816 5817<p>The <em class="arg">color</em> argument is defined using the format 5818described under the <a href="#fill">-fill</a> option. The <a href="#fuzz" 5819>-fuzz</a> setting can be used to match and replace colors similar to the one 5820given. </p> 5821 5822<p>Use <a href="#transparent" >+transparent</a> to invert the pixels matched. 5823that is make all non-matching colors transparent. </p> 5824 5825<p>The <a href="#opaque">-opaque</a> operator is exactly the same as <a 5826href="#transparent" >-transparent</a> but replaces the matching color with the 5827current <a href="#fill">-fill</a> color setting, rather than transparent. 5828However the <a href="#transparent" >-transparent</a> operator also ensures 5829that the image has an alpha channel enabled, as per "<kbd><a href="#alpha" 5830>-alpha</a> set</kbd>", and does not require you to modify the <a 5831href="#channel">-channel</a> to enable alpha channel handling. </p> 5832 5833<p>Note that this does not define the color as being the 'transparency color' 5834used for color-mapped image formats, such as GIF. For that use <a 5835href="#transparent-color" >-transparent-color</a> </p> 5836 5837 5838<div style="margin: auto;"> 5839 <h4><a id="transparent-color"></a>-transparent-color <em class="arg">color</em></h4> 5840</div> 5841 5842<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the transparent color.</td><td style='text-align:right;'></td></tr></table> 5843 5844<p>Sometimes this is used for saving to image formats such as 5845GIF and PNG8 which uses this color to represent boolean transparency. This 5846does not make a color transparent, it only defines what color the transparent 5847color is in the color palette of the saved image. Use <a 5848href="#transparent">-transparent</a> to make an opaque color transparent.</p> 5849 5850<p>This option allows you to have both an opaque visible color, as well as a 5851transparent color of the same color value without conflict. That is, you can 5852use the same color for both the transparent and opaque color areas within an 5853image. This, in turn, frees to you to select a transparent color that is 5854appropriate when an image is displayed by an application that does not handle a 5855transparent color index, while allowing ImageMagick to correctly handle images of this 5856type. </p> 5857 5858<p>The default transparent color is <kbd>#00000000</kbd>, which is fully transparent black.</p> 5859 5860<div style="margin: auto;"> 5861 <h4><a id="transpose"></a>-transpose</h4> 5862</div> 5863 5864<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Mirror the image along the top-left to bottom-right diagonal.</td><td style='text-align:right;'></td></tr></table> 5865 5866<p> This option mathematically transposes the pixel array. It is equivalent to the sequence <kbd>-flip -rotate 90</kbd>. 5867</p> 5868 5869<div style="margin: auto;"> 5870 <h4><a id="transverse"></a>-transverse</h4> 5871</div> 5872 5873<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Mirror the image along the images bottom-left top-right diagonal. Equivalent to the operations <kbd>-flop -rotate 90</kbd>.</td><td style='text-align:right;'></td></tr></table> 5874 5875 5876<div style="margin: auto;"> 5877 <h4><a id="treedepth"></a>-treedepth <em class="arg">value</em></h4> 5878</div> 5879 5880<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>tree depth for the color reduction algorithm.</td><td style='text-align:right;'></td></tr></table> 5881 5882<p>Normally, this integer value is zero or one. A value of zero or one causes the use of an optimal tree depth for the color reduction algorithm.</p> 5883 5884<p>An optimal depth generally allows the best representation of the source image with the fastest computational speed and the least amount of memory. However, the default depth is inappropriate for some images. To assure the best representation, try values between 2 and 8 for this parameter. Refer to the <a href="/www/quantize.html">color reduction algorithm</a> for more details.</p> 5885 5886<p>The <a href="#colors">-colors</a> or <a href="#monochrome">-monochrome</a> option, or writing to an image format which requires color reduction, is required for this option to take effect.</p> 5887 5888<div style="margin: auto;"> 5889 <h4><a id="trim"></a>-trim</h4> 5890</div> 5891 5892<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>trim an image.</td><td style='text-align:right;'></td></tr></table> 5893 5894<p>This option removes any edges that are exactly the same color as the corner pixels. Use <a href="#fuzz">-fuzz</a> to make <a href="#trim">-trim</a> remove edges that are nearly the same color as the corner pixels.</p> 5895 5896<p>The page or virtual canvas information of the image is preserved allowing 5897you to extract the result of the <a href="#trim">-trim</a> operation from the 5898image. Use a <a href="#repage">+repage</a> to remove the virtual canvas page 5899information if it is unwanted.</p> 5900 5901<p>If the trimmed image 'disappears' an warning is produced, and a special 5902single pixel transparent 'missed' image is returned, in the same way as when a 5903<a href="#crop">-crop</a> operation 'misses' the image proper. </p> 5904 5905 5906<div style="margin: auto;"> 5907 <h4><a id="type"></a>-type <em class="arg">type</em></h4> 5908</div> 5909 5910<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the image type.</td><td style='text-align:right;'></td></tr></table> 5911 <p>Choose from: <kbd>Bilevel</kbd>, <kbd>Grayscale</kbd>, <kbd>GrayscaleMatte</kbd>, <kbd>Palette</kbd>, <kbd>PaletteMatte</kbd>, <kbd>TrueColor</kbd>, <kbd>TrueColorMatte</kbd>, <kbd>ColorSeparation</kbd>, or <kbd>ColorSeparationMatte</kbd>.</p> 5912 5913<p>Normally, when a format supports different subformats such as grayscale and truecolor, the encoder will try to choose an efficient subformat. The <a href="#type">-type</a> option can be used to overrride this behavior. For example, to prevent a JPEG from being written in grayscale format even though only gray pixels are present, use.</p> 5914 5915<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert bird.png -type TrueColor bird.jpg</span></p> 5916<p>Similarly, use <a href="#type">-type TrueColorMatte</a> to force the encoder to write an alpha channel even though the image is opaque, if the output format supports transparency.</p> 5917 5918<p>Use <a href="#type">-type optimize</a> to ensure the image is written in the smallest possible file size.</p> 5919 5920<div style="margin: auto;"> 5921 <h4><a id="undercolor"></a>-undercolor <em class="arg">color</em></h4> 5922</div> 5923 5924<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>set the color of the annotation bounding box.</td><td style='text-align:right;'></td></tr></table> 5925 5926<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 5927 5928<p>See <a href="#draw">-draw</a> for further details.</p> 5929 5930 5931<div style="margin: auto;"> 5932 <h4><a id="update"></a>-update <em class="arg">seconds</em></h4> 5933</div> 5934 5935<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>detect when image file is modified and redisplay.</td><td style='text-align:right;'></td></tr></table> 5936 5937<p>Suppose that while you are displaying an image the file that is currently displayed is over-written. <kbd>display</kbd> will automagically detect that the input file has been changed and update the displayed image accordingly.</p> 5938 5939 5940<div style="margin: auto;"> 5941 <h4><a id="unique-colors"></a>-unique-colors</h4> 5942</div> 5943 5944<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>discard all but one of any pixel color.</td><td style='text-align:right;'></td></tr></table> 5945 5946 5947<div style="margin: auto;"> 5948 <h4><a id="units"></a>-units <em class="arg">type</em></h4> 5949</div> 5950 5951<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the units of image resolution.</td><td style='text-align:right;'></td></tr></table> 5952 5953<p>Choose from: <kbd>Undefined</kbd>, <kbd>PixelsPerInch</kbd>, or <kbd>PixelsPerCentimeter</kbd>. This option is normally used in conjunction with the <a href="#density">-density</a> option.</p> 5954 5955 5956<div style="margin: auto;"> 5957 <h4><a id="unsharp"></a>-unsharp <em class="arg">radius</em><br />-unsharp <em class="arg">radius</em>x<em class="arg">sigma</em>{<em class="arg">+amount</em>}{<em class="arg">+threshold</em>}</h4> 5958</div> 5959 5960<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>sharpen the image with an unsharp mask operator.</td><td style='text-align:right;'></td></tr></table> 5961 5962<p>The <a href="#unsharp">-unsharp</a> option sharpens an image. The image is convolved with a Gaussian operator of the given radius and standard deviation (sigma). For reasonable results, radius should be larger than sigma. Use a radius of 0 to have the method select a suitable radius.</p> 5963 5964<p>The parameters are:</p> 5965 5966<pre class="text"> 5967 radius: The radius of the Gaussian, in pixels, not counting the center 5968 pixel (default 0). 5969 sigma: The standard deviation of the Gaussian, in pixels (default 1.0). 5970 amount: The fraction of the difference between the original and the blur 5971 image that is added back into the original (default 1.0). 5972 threshold: The threshold, as a fraction of <em class="QR">QuantumRange</em>, needed to apply the 5973 difference amount (default 0.05). 5974</pre> 5975 5976 5977<div style="margin: auto;"> 5978 <h4><a id="verbose"></a>-verbose</h4> 5979</div> 5980 5981<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>print detailed information about the image when this option precedes the <a href="#identify">-identify</a> option or <kbd>info:</kbd>.</td><td style='text-align:right;'></td></tr></table> 5982 5983 5984<div style="margin: auto;"> 5985 <h4><a id="version"></a>-version</h4> 5986</div> 5987 5988<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>print ImageMagick version string and exit.</td><td style='text-align:right;'></td></tr></table> 5989 5990 5991<div style="margin: auto;"> 5992 <h4><a id="view"></a>-view <em class="arg">string</em></h4> 5993</div> 5994 5995<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>FlashPix viewing parameters.</td><td style='text-align:right;'></td></tr></table> 5996 5997 5998<div style="margin: auto;"> 5999 <h4><a id="vignette"></a>-vignette <em class="arg">radius</em>{x<em class="arg">sigma</em>}{<em class="arg">+-</em>}<em class="arg">x</em>{<em class="arg">+-</em>}<em class="arg">y</em>{<em class="arg">%</em>}</h4> 6000</div> 6001 6002<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>soften the edges of the image in vignette style.</td><td style='text-align:right;'></td></tr></table> 6003 6004 6005<div style="margin: auto;"> 6006 <h4><a id="virtual-pixel"></a>-virtual-pixel <em class="arg">method</em></h4> 6007</div> 6008 6009<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specify contents of <em>virtual pixels</em>.</td><td style='text-align:right;'></td></tr></table> 6010 6011<p>This option defines what color source should be used if and when a color 6012lookup completely 'misses' the source image. The color(s) that appear to 6013surround the source image. Generally this color is derived from the source 6014image, but could also be set to a specify background color. </p> 6015 6016<p>Choose from these methods:</p> 6017 6018<pre class="text"> 6019 background: the area surrounding the image is the background color 6020 black: the area surrounding the image is black 6021 checker-tile: alternate squares with image and background color 6022 dither: non-random 32x32 dithered pattern 6023 edge: extend the edge pixel toward infinity 6024 gray: the area surrounding the image is gray 6025 horizontal-tile: horizontally tile the image, background color above/below 6026 horizontal-tile-edge: horizontally tile the image and replicate the side edge pixels 6027 mirror: mirror tile the image 6028 random: choose a random pixel from the image 6029 tile: tile the image (default) 6030 transparent: the area surrounding the image is transparent blackness 6031 vertical-tile: vertically tile the image, sides are background color 6032 vertical-tile-edge: vertically tile the image and replicate the side edge pixels 6033 white: the area surrounding the image is white 6034</pre> 6035 6036<p>The default value is "edge".</p> 6037 6038<p>This most important for distortion operators such as <a href="#distort" 6039>-distort</a>, <a href="#implode" >-implode</a>, and <a href="#fx" >-fx</a>. 6040However it also effects operations that may access pixels just outside the 6041image proper, such as <a href="#convolve">-convolve</a>, <a 6042href="#blur">-blur</a>, and <a href="#sharpen">-sharpen</a>. </p> 6043 6044<p>To print a complete list of virtual pixel types, use the <a href="#list">-list virtual-pixel</a> option.</p> 6045 6046 6047<div style="margin: auto;"> 6048 <h4><a id="visual"></a>-visual <em class="arg">type</em></h4> 6049</div> 6050 6051<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Animate images using this X visual type.</td><td style='text-align:right;'>[<a href="/www/animate.html">animate</a>, <a href="/www/display.html">display</a>]</td></tr></table> 6052 6053<p>Choose from these visual classes:</p> 6054 6055<pre class="text"> 6056 StaticGray 6057 GrayScale 6058 StaticColor 6059 PseudoColor 6060 TrueColor 6061 DirectColor 6062 default 6063 visual id 6064</pre> 6065 6066<p>The X server must support the visual you choose, otherwise an error occurs. If a visual is not specified, the visual class that can display the most simultaneous colors on the default screen is chosen.</p> 6067 6068 6069<div style="margin: auto;"> 6070 <h4><a id="watermark"></a>-watermark <em 6071 class="arg">brightness</em>x<em class="arg">saturation</em></h4> 6072</div> 6073 6074<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Watermark an image using the given percentages of brightness and 6075saturation.</td><td style='text-align:right;'>[<a href="/www/composite.html">composite</a>]</td></tr></table> 6076 6077<p>Take a grayscale image (with alpha mask) and modify the destination image's 6078brightness according to watermark image's grayscale value and the <em 6079class="arg">brightness</em> percentage. The destinations color saturation 6080attribute is just direct modified by the <em class="arg">saturation</em> 6081percentage, which defaults to 100 percent (no color change). </p> 6082 6083 6084<div style="margin: auto;"> 6085 <h4><a id="wave"></a>-wave <em class="arg">amplitude</em><br />-wave <em class="arg">amplitude</em>x<em class="arg">wavelength</em></h4> 6086</div> 6087 6088<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Shear the columns of an image into a sine wave.</td><td style='text-align:right;'></td></tr></table> 6089 6090<p>Specify <em class="arg">amplitude</em> and <em class="arg">wavelength</em> of the wave.</p> 6091 6092<div style="margin: auto;"> 6093 <h4><a id="weight"></a>-weight <em class="arg">fontWeight</em></h4> 6094</div> 6095 6096<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set a font weight for text.</td><td style='text-align:right;'></td></tr></table> 6097 6098<p>This setting suggests a font weight that ImageMagick should try to apply to the currently selected font family. Use a positive integer for <em class="arg">fontWeight</em> or select from the following.</p> 6099 6100<table class="doc"> 6101 <col width="25%" /> 6102 <col width="75%" /> 6103 <thead> 6104 <tr> 6105 <th><em class="arg">fontWeight</em></th> 6106 <th>Description</th> 6107 </tr> 6108 </thead> 6109 <tbody> 6110 <tr><td>All </td> <td>No effect. </td></tr> 6111 <tr><td>Bold </td> <td>Same as <em class="arg">fontWeight</em> = 700.</td></tr> 6112 <tr><td>Bolder </td> <td>Add 100 to font weight if currently ≤ 800.</td></tr> 6113 <tr><td>Lighter </td> <td>Subtract 100 to font weight if currently ≤ 100.</td></tr> 6114 <tr><td>Normal </td> <td>Same as <em class="arg">fontWeight</em> = 400.</td></tr> 6115 </tbody> 6116 </table> 6117 6118<p>To print a complete list of weight types, use <a href="#list">-list weight</a>.</p> 6119 6120<p>For other settings that affect fonts, see the options <a href="#font">-font</a>, <a href="#family">-family</a>, <a href="#stretch">-stretch</a>, and <a href="#style">-style</a>. </p> 6121 6122<div style="margin: auto;"> 6123 <h4><a id="white-point"></a>-white-point <em class="arg">x,y</em></h4> 6124</div> 6125 6126<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>chromaticity white point.</td><td style='text-align:right;'></td></tr></table> 6127 6128<div style="margin: auto;"> 6129 <h4><a id="white-threshold"></a>-white-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 6130</div> 6131 6132<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Force to white all pixels above the threshold while leaving all pixels at or below the threshold unchanged.</td><td style='text-align:right;'></td></tr></table> 6133 6134<p> The threshold value can be given as a percentage or as an absolute integer value within [0, <em class="QR">QuantumRange</em>] corresponding to the desired <a href="/www/command-line-options.html#channel">‑channel</a> value. See <a href="/www/command-line-options.html#threshold">‑threshold</a> for more details on thresholds and resulting values. 6135</p> 6136 6137<div style="margin: auto;"> 6138 <h4><a id="window"></a>-window <em class="arg">id</em></h4> 6139</div> 6140 6141<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Make the image the background of a window.</td><td style='text-align:right;'>[<a href="/www/animate.html">animate</a>, <a href="/www/display.html">display</a>]</td></tr></table> 6142 6143<p><em class="arg">id</em> can be a window id or name. Specify <kbd>root</kbd> to select X's root window as the target window.</p> 6144 6145<p>By default the image is tiled onto the background of the target window. If <kbd>backdrop</kbd> or <a href="#geometry">-resize</a> are specified, the image is surrounded by the background color. Refer to <kbd>X RESOURCES</kbd> for details.</p> 6146 6147<p>The image will not display on the root window if the image has more unique colors than the target window colormap allows. Use <a href="#colors">-colors</a> to reduce the number of colors.</p> 6148 6149<div style="margin: auto;"> 6150 <h4><a id="window-group"></a>-window-group</h4> 6151</div> 6152 6153<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>specify the window group.</td><td style='text-align:right;'></td></tr></table> 6154 6155<div style="margin: auto;"> 6156 <h4><a id="write"></a>-write <em class="arg">filename</em></h4> 6157</div> 6158 6159<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>write an image sequence.</td><td style='text-align:right;'></td></tr></table> 6160 <p>The image sequence preceding the <a href="#write">-write</a> <em class="arg">filename</em> 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="#write">+write</a> <em class="arg">filename</em> option.</p> 6161 6162<p>Use <a href="#compress">-compress</a> to specify the type of image compression.</p> 6163</div> 6164</div> 6165 6166</div> 6167 6168<div id="linkbar"> 6169 <span id="linkbar-west"> </span> 6170 <span id="linkbar-center"> 6171 <a href="http://www.imagemagick.org/discourse-server/">Discourse Server</a> • 6172 <a href="http://www.imagemagick.org/MagickStudio/scripts/MagickStudio.cgi">Studio</a> 6173 </span> 6174 <span id="linkbar-east"> </span> 6175 </div> 6176 <div class="footer"> 6177 <span id="footer-west">© 1999-2011 ImageMagick Studio LLC</span> 6178 <span id="footer-east"> <a href="http://www.imagemagick.org/script/contact.php">Contact the Wizards</a></span> 6179 </div> 6180 <div style="clear: both; margin: 0; width: 100%; "></div> 6181 <script type="text/javascript"> 6182 var _gaq = _gaq || []; 6183 _gaq.push(['_setAccount', 'UA-17690367-1']); 6184 _gaq.push(['_trackPageview']); 6185 6186 (function() { 6187 var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; 6188 ga.src = ('https:' == document.location.protocol ? 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