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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#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#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> 179 180<p>Below is list of command-line options recognized by the ImageMagick <a 181href="/www/command-line-tools.html">command-line 182tools</a>. If you want a description of a particular option, click on the 183option name in the navigation bar above and you will go right to it. Unless 184otherwise noted, each option is recognized by the commands <a href="/www/convert.html">convert</a>, <a href="/www/mogrify.html">mogrify</a>.</p> 185 186<div style="margin: auto;"> 187 <h4><a name="adaptive-blur" id="adaptive-blur"></a>-adaptive-blur <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4> 188</div> 189 190<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> 191<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> 192 193<div style="margin: auto;"> 194 <h4><a name="adaptive-resize" id="adaptive-resize"></a>-adaptive-resize <em class="arg">geometry</em></h4> 195</div> 196 197<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> 198 199<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> 200 201<div style="margin: auto;"> 202 <h4><a name="adaptive-sharpen" id="adaptive-sharpen"></a>-adaptive-sharpen <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4> 203</div> 204 205<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> 206 207<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> 208 209<div style="margin: auto;"> 210 <h4><a name="adjoin" id="adjoin"></a>-adjoin</h4> 211</div> 212 213<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> 214 215<p>This option is enabled by default. An attempt is made to save all 216images of an image sequence into the given output file. 217However, some formats, such as JPEG and PNG, do not support more than one 218image per file, and in that case ImageMagick is forced to write each image as a separate file. As 219such, if more than one image needs to be written, the filename given is 220modified by adding a <a href="#scene">-scene</a> number before the 221suffix, in order to make distinct names for each image. </p> 222 223<p>Use <a href="#adjoin">+adjoin</a> to force each image to be written 224to separate files, whether or not the file format allows multiple images 225per file (for example, GIF, MIFF, and TIFF). </p> 226 227<p>Including a C-style integer format string in the output filename will automagically enable <a href="#adjoin">+adjoin</a> and are used to specify where the <a href="#scene">-scene</a> number is placed in the filenames. These strings, such as '<kbd>%d</kbd>' or '<kbd>%03d</kbd>', are familiar to those who have used the standard <kbd>printf()</kbd>' C-library function. As an example, the command</p> 228 229<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert logo: rose: -morph 15 my%02dmorph.jpg</span></p> 230<p>will create a sequence of 17 images named my00morph.jpg, my01morph.jpg, my02morph.jpg, ..., my16morph.jpg. 231</p> 232 233<p>In summary, ImageMagick tries to write all images to one file, but will use 234multiple files if either (1) the output image's file format does not allow multi-image files, 235(2) the <a href="#adjoin">+adjoin</a> option is given, or (3) a C-style integer format string is 236present in the output filename. </p> 237 238 239<div style="margin: auto;"> 240 <h4><a name="affine" id="affine"></a>-affine <em class="arg">s<sub>x</sub></em>,<em class="arg">r<sub>x</sub></em>,<em class="arg">r<sub>y</sub></em>,<em class="arg">s<sub>y</sub></em>,<em class="arg">t<sub>x</sub></em>,<em class="arg">t<sub>y</sub></em><br/> 241 -affine <em class="arg">s<sub>x</sub></em>,<em class="arg">r<sub>x</sub></em>,<em class="arg">r<sub>y</sub></em>,<em class="arg">s<sub>y</sub></em></h4> 242</div> 243 244<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> 245 246<p>This option sets a transformation matrix, encoded as (<em class="arg">s<sub>x</sub></em>, <em class="arg">r<sub>x</sub></em>, <em class="arg">r<sub>y</sub></em>, <em class="arg">s<sub>y</sub></em>, <em class="arg">t<sub>x</sub></em>, <em class="arg">t<sub>y</sub></em>), for use by subsequent <a href="#draw">-draw</a> or <a href="#transform">-transform</a> options.</p> 247 248<p>The matrix entries are entered as comma-separated numeric values <i>with no spaces</i>. </p> 249 250<p>Internally, the transformation matrix has 3x3 elements, but three of them are omitted from the input because they are constant. 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 original image are calculated using the following matrix equation.</p> 251 252<div class="eqn"> 253<img alt="affine transformation" src="/images/affine.png"/> 254</div> 255 256<p> 257The size of the resulting image is that of the smallest rectangle that contains the transformed source image. The parameters <em class="arg">t<sub>x</sub></em> and <em class="arg">t<sub>y</sub></em> subsequently shift the image pixels so that those that are moved out of the image area are cut off.</p> 258 259<p>The transformation matrix complies with the left-handed pixel coordinate system: positive <em class="arg">x</em> and <em class="arg">y</em> directions are rightward and downward, resp.; positive rotation is clockwise.</p> 260 261<p> If the translation coefficients <em class="arg">t<sub>x</sub></em> and <em class="arg">t<sub>y</sub></em> are omotted they default to 0,0. Therefore, four parameters suffice for rotation and scaling without translation.</p> 262 263<p>Scaling by the factors <em class="arg">s<sub>x</sub></em> and <em class="arg">s<sub>y</sub></em> in the <em>x</em> and <em>y</em> directions, respectively, is accomplished with the following.</p> 264 265<p class="crtsnip"> 266 -affine <em class="arg">s<sub>x</sub></em>,0,0,<em class="arg">s<sub>y</sub></em> 267</p> 268 269<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> 270 271<p class="crtsnip"> 272 -affine 1,0,0,1,<em class="arg">t<sub>x</sub></em>,<em class="arg">t<sub>y</sub></em> 273</p> 274 275<p>Rotate clockwise about the origin (the upper left-hand corner) by an angle <em>a</em> by letting 276<em>c</em> = cos(<em>a</em>), <em>s</em> = sin(<em>a</em>), and using the following.</p> 277 278<p class="crtsnip"> 279 -affine <em>c</em>,<em>s</em>,-<em>s</em>,<em>c</em> 280</p> 281 282<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> 283 284<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> 285 286<div style="margin: auto;"> 287 <h4><a name="alpha" id="alpha"></a>-alpha <em class="arg">type</em></h4> 288</div> 289 290<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> 291 292<p>Used to set a flag on an image indicating whether or not to use existing alpha 293channel 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> 294 295 296<table class="doc"> 297 <tbody> 298 <tr valign="top"> 299 <th align="left" style="width: 8%">type</th> 300 <th align="left">Description</th> 301 </tr> 302 303 <tr valign="top"> 304 <td valign="top"><kbd>Activate</kbd> or <kbd>On</kbd></td> 305 <td valign="top"> 306 Enable the image's transparency channel. Note normally <kbd>Set</kbd> 307 should be used instead of this, unless you specifically need to 308 preserve existing (but specifically turned <kbd>Off</kbd>) transparency 309 channel. </td></tr> 310 311 <tr valign="top"> 312 <td valign="top"><kbd>Deactivate</kbd> or <kbd>Off</kbd></td> 313 <td valign="top"> 314 Disables the image's transparency channel. Does not delete or change the 315 existing data, just turns off the use of that data.</td></tr> 316 317 <tr valign="top"> 318 <td valign="top"><kbd>Set</kbd></td> 319 <td valign="top"> 320 Activates the alpha/matte channel. If it was previously turned off 321 then it also resets the channel to opaque. If the image already had 322 the alpha channel turned on, it will have no effect.</td></tr> 323 324 <tr valign="top"> 325 <td valign="top"><kbd>Opaque</kbd></td> 326 <td valign="top"> 327 Enables the alpha/matte channel and forces it to be fully opaque. 328 </td></tr> 329 330 <tr valign="top"> 331 <td valign="top"><kbd>Transparent</kbd></td> 332 <td valign="top"> 333 Activates the alpha/matte channel and forces it to be fully 334 transparent. This effectively creates a fully transparent image the 335 same size as the original and with all its original RGB data still 336 intact, but fully transparent. </td></tr> 337 338 <tr valign="top"> 339 <td valign="top"><kbd>Extract</kbd></td> 340 <td valign="top"> 341 Copies the alpha channel values into all the color channels and turns 342 '<kbd>Off</kbd>' the the image's transparency, so as to generate 343 a gray-scale mask of the image's shape. The alpha channel data is left 344 intact just deactivated. This is the inverse of '<kbd>Copy</kbd>'. 345 </td></tr> 346 347 <tr valign="top"> 348 <td valign="top"><kbd>Copy</kbd></td> 349 <td valign="top"> 350 Turns '<kbd>On</kbd>' the alpha/matte channel, then copies the 351 gray-scale intensity of the image, into the alpha channel, converting 352 a gray-scale mask into a transparent shaped mask ready to be colored 353 appropriately. The color channels are not modified. </td></tr> 354 355 <tr valign="top"> 356 <td valign="top"><kbd>Shape</kbd></td> 357 <td valign="top"> 358 As per '<kbd>Copy</kbd>' but also colors the resulting shape mask with 359 the current background color. That is the RGB color channels is 360 replaced, with appropriate alpha shape. 361 </td></tr> 362 363 <tr valign="top"> 364 <td valign="top"><kbd>Background</kbd></td> 365 <td valign="top"> 366 Set any fully-transparent pixel to the background color, while leaving 367 it fully-transparent. This can make some image file formats, such as 368 PNG, smaller as the RGB values of transparent pixels are more uniform, 369 and thus can compress better. 370 </td></tr> 371 </tbody> 372</table> 373 374<p>Note that while the <a href="#matte" >+matte</a> operation is the same as 375"<kbd><a href="#alpha" >-alpha</a> Off</kbd>", the <a href="#matte" 376>-matte</a> operation is the same as "<kbd><a href="#alpha" >-alpha</a> 377Set</kbd>" and not "<kbd><a href="#alpha" >-alpha</a> On</kbd>". </p> 378 379 380<div style="margin: auto;"> 381 <h4><a name="annotate" id="annotate"></a> 382 -annotate <em class="arg">degrees</em> <em class="arg">text</em><br /> 383 -annotate <em class="arg">Xdegrees</em>x<em class="arg">Ydegrees</em> <em class="arg">text</em><br /> 384 -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> 385</div> 386 387<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> 388 389<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> 390 391 392<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> 393 394<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> 395 396<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> 397<div class="eqn"><img alt="annotate transformation" src="/images/annotate.png"/></div> 398 399<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> 400 401<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> 402 403<div style="margin: auto;"> 404 <h4><a name="antialias" id="antialias"></a>-antialias</h4> 405</div> 406 407<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 408drawing fonts and lines.</td><td style='text-align:right;'></td></tr></table> 409 410<p>By default, objects (e.g. text, lines, polygons, etc.) are antialiased when 411drawn. Use <a href="#antialias">+antialias</a> to disable the addition of 412antialiasing edge pixels. This will then reduce the number of colors added to 413an image to just the colors being directly drawn. That is, no mixed colors 414are added when drawing such objects. </p> 415 416<div style="margin: auto;"> 417 <h4><a name="append" id="append"></a>-append</h4> 418</div> 419 420<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> 421 422<p>This option creates a single longer image image, by joining all the current 423images in sequence top-to-bottom. Use <a href="#append">+append</a> to 424stack images left-to-right. </p> 425 426<p>If they are not of the same width, narrower images are padded with the 427current <a href="#background">-background</a> color setting, and their 428position relative to each other can be controlled by the current <a 429href="#gravity">-gravity</a> setting. </p> 430 431 432<div style="margin: auto;"> 433 <h4><a name="attenuate" id="attenuate"></a>-attenuate <em class="arg">value</em></h4> 434</div> 435 436<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> 437 438 439<div style="margin: auto;"> 440 <h4><a name="authenticate" id="authenticate"></a>-authenticate <em class="arg">password</em></h4> 441</div> 442 443<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> 444 445<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> 446 447<p>For a different encryption method, see <a href="#encipher">-encipher</a> and <a href="#decipher">-decipher</a>. </p> 448 449 450 451<div style="margin: auto;"> 452 <h4><a name="auto-gamma" id="auto-gamma"></a>-auto-gamma</h4> 453</div> 454 455<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> 456 457<p>This calculates the mean values of an image, then applies a calculated <a 458href="#gamma" >-gamma</a> adjustment so that is the mean color exists in the 459image it will get a have a value of 50%. </p> 460 461<p>This means that any solid 'gray' image becomes 50% gray. </p> 462 463<p>This works well for real-life images with little or no extreme dark and 464light areas, but tend to fail for images with large amounts of bright sky or 465dark shadows. It also does not work well for diagrams or cartoon like images. 466</p> 467 468<p>It uses the <a href="#channel" >-channel</a> setting, (including the 469'<CODE>sync</CODE>' flag for channel syncronization), to determine which color 470values is used and modified. As the default <a href="#channel" 471>-channel</a> setting is '<CODE>RGB,sync</CODE>', channels are modified 472together by the same gamma value, preserving colors. </p> 473 474 475 476<div style="margin: auto;"> 477 <h4><a name="auto-level" id="auto-level"></a>-auto-level</h4> 478</div> 479 480<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> 481 482<p>This is a 'perfect' image normalization operator. It finds the exact 483minimum and maximum color values in the image and then applies a <a 484href="#level" >-level</a> operator to stretch the values to the full range of 485values. </p> 486 487<p>The operator is not typically used for real-life images, image scans, or 488JPEG format images, as a single 'out-rider' pixel can set a bad min/max values 489for the <a href="#level" >-level</a> operation. On the other hand it is the 490right operator to use for color stretching gradient images being used to 491generate Color lookup tables, distortion maps, or other 'mathematically' 492defined images. </p> 493 494<p>The operator is very similar to the <a href="#normalize">-normalize</a>, <a 495href="#contrast-stretch" >-contrast-stretch</a>, and <a href="#linear-stretch" 496>-linear-stretch</a> operators, but without 'histogram binning' or 'clipping' 497problems that these operators may have. That is <a href="#auto-level" 498>-auto-level</a> is the perfect or ideal version these operators. </p> 499 500<p>It uses the <a href="#channel" >-channel</a> setting, (including the 501special '<CODE>sync</CODE>' flag for channel syncronization), to determine 502which color values are used and modified. As the default <a 503href="#channel" >+channel</a> setting is '<CODE>RGB,sync</CODE>', the 504'<CODE>sync</CODE>' ensures that the color channels will are modified 505together by the same gamma value, preserving colors, and ignoring 506transparency. </p> 507 508 509<div style="margin: auto;"> 510 <h4><a name="auto-orient" id="auto-orient"></a>-auto-orient</h4> 511</div> 512 513<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> 514 515<p>This operator reads and resets the EXIF image profile setting 'Orientation' 516and then performs the appropriate 90 degree rotation on the image to orient 517the image, for correct viewing. </p> 518 519<p>This EXIF profile setting is usually set using a gravity sensor in digital 520camara, however photos taken directly downward or upward may not have an 521appropriate value. Also images that have been orientation 'corrected' without 522reseting this setting, may be 'corrected' again resulting in a incorrect 523result. If the he EXIF profile was previously stripped, the <a 524href="#auto-orient" >-auto-orient</a> operator will do nothing. </p> 525 526 527<div style="margin: auto;"> 528 <h4><a name="average" id="average"></a>-average</h4> 529</div> 530 531<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> 532 533<p>An error results if the images are not identically sized.</p> 534 535 536<div style="margin: auto;"> 537 <h4><a name="backdrop" id="backdrop"></a>-backdrop</h4> 538</div> 539 540<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> 541 542<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> 543 544<div style="margin: auto;"> 545 <h4><a name="background" id="background"></a>-background <em class="arg">color</em></h4> 546</div> 547 548<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> 549 550<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> 551 552<div style="margin: auto;"> 553 <h4><a name="bench" id="bench"></a>-bench <em class="arg">iterations</em></h4> 554</div> 555 556<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> 557 558<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> 559 560<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> 561<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> 562 563<div style="margin: auto;"> 564 <h4><a name="bias" id="bias"></a>-bias <em class="arg">value</em>{<em class="arg">%</em>}</h4> 565</div> 566 567<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> 568 569<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> 570 571<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> 572 573<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 574negative results without clipping to the color value range 575(0..QuantumRange).</p> 576 577<p>See the discussion on HDRI implementations of ImageMagick on the page 578<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. 579</p> 580 581<div style="margin: auto;"> 582 <h4><a name="black-point-compensation" id="black-point-compensation"></a>-black-point-compensation</h4> 583</div> 584 585<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> 586 587<div style="margin: auto;"> 588 <h4><a name="black-threshold" id="black-threshold"></a>-black-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 589</div> 590 591<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> 592 593<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. 594</p> 595 596 597<div style="margin: auto;"> 598 <h4><a name="blend" id="blend"></a>-blend <em class="arg">geometry</em></h4> 599</div> 600 601<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> 602 603<p>Blend will average the images together ('plus') according to the 604percentages given and each pixels transparency. If only a single percentage 605value is given it sets the weight of the composite or 'source' image, while 606the background image is weighted by the exact opposite amount. That is a 607<kbd>-blend 30%</kbd> merges 30% of the 'source' image with 70% of the 608'destination' image. Thus it is equivalent to <kbd>-blend 30x70%</kbd>.</p> 609 610 611<div style="margin: auto;"> 612 <h4><a name="blue-primary" id="blue-primary"></a>-blue-primary <em class="arg">x</em>,<em class="arg">y</em></h4> 613</div> 614 615<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> 616 617<div style="margin: auto;"> 618 <h4><a name="blue-shift" id="blue-shift"></a>-blue-shift <em class="arg">factor</em></h4> 619</div> 620 621<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> 622 623<div style="margin: auto;"> 624 625<div style="margin: auto;"> 626 <h4><a name="blur" id="blur"></a>-blur <em class="arg">radius</em><br />-blur <em class="arg">radius</em>x<em class="arg">sigma</em></h4> 627</div> 628 629<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> 630 631<p>Convolve the image with a Gaussian or normal distribution using the given 632<em class="arg" >Sigma</em> value. The formula is:</p> 633 634<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="/images/gaussian-blur.png"/> 635</div> 636 637<p>The <em class="arg" >Sigma</em> value is the important argument, and 638determines the actual amount of bluring that will take place. </p> 639 640<p>The <em class="arg" >Radius</em> is only used to determine the size of the 641array which will hold the calculated gaussian distribution. It should be an 642integer. If not given, or set to zero, IM will calculate the largest possible 643radius that will provide meaningful results for the Gaussian distribution. 644</p> 645 646<p>The larger the <em class="arg" >Radius</em> the radius the slower the 647operation is. However too small a <em class="arg" >Radius</em>, and sever 648aliasing effects may result. As a guideline, <em class="arg" >Radius</em> 649should be at least twice the <em class="arg" >Sigma</em> value, though three 650times will produce a more accurite result. </p> 651 652<p>This option differs from <a href="#gaussian-blur">-gaussian-blur</a> simply 653by taking advantage of the separability properties of the distribution. Here 654we apply a single-dimensional Gaussian matrix in the horizontal direction, 655then repeat the process in the vertical direction.</p> 656 657<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 658pixels which are outside the image proper are blurred into the final result. 659</p> 660 661 662<div style="margin: auto;"> 663 <h4><a name="blur-composite" id="blur"></a>-blur <em class="arg">Width</em>[x<em class="arg">Height</em>[+<em class="arg">Angle</em>]]</h4> 664</div> 665 666<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> 667 668<p>Each pixel in the overlaid region is replaced with an Elliptical Weighted 669Average (EWA) of the source image, scaled according to the grayscale 670mapping. </p> 671 672<p>The ellipse is weighted with sigma set to the given <em class="arg" 673>Width</em> and <em class="arg" >Height</em>. The <em class="arg" >Height</em> 674defaults to the <em class="arg" >Width</em> for a normal circular Guassian 675weighting. The <em class="arg" >Angle</em> will rotate the ellipse from 676horizontal clock-wise. </p> 677 678<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 679pixels which are outside the image proper are blurred into the final result. 680</p> 681 682 683<div style="margin: auto;"> 684 <h4><a name="border" id="border"></a>-border <em class="arg">geometry</em></h4> 685</div> 686 687<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> 688 689<p>Set the width and height using the <em class="arg">size</em> portion of the 690<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 691ignored. </p> 692 693<p>Set the border color by preceding with the <a 694href="#bordercolor">-bordercolor</a> setting.</p> 695 696<p>The <a href="#border">-border</a> operation is affected by the current <a 697href="#compose">-compose</a> setting and assumes that this is using the default 698'<kbd>Over</kbd>' composition method. It generates a image of the appropriate 699size colors by the current <a href="#bordercolor">-bordercolor</a> before 700overlaying the original image in the center of this net image. This means that 701with the default compose method of '<kbd>Over</kbd>' any transparent parts may 702be replaced by the current <a href="#bordercolor">-bordercolor</a> setting.</p> 703<p>See also the <a href="#frame">-frame</a> option, which has more 704functionality.</p> 705 706<div style="margin: auto;"> 707 <h4><a name="bordercolor" id="bordercolor"></a>-bordercolor <em class="arg">color</em></h4> 708</div> 709 710<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> 711 712<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 713 714<p>The default border color is <kbd>#DFDFDF</kbd>, <span style="background-color: #dfdfdf;">this shade of gray</span>.</p> 715 716<div style="margin: auto;"> 717 <h4><a name="borderwidth" id="borderwidth"></a>-borderwidth <em class="arg">geometry</em> </h4> 718</div> 719 720<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> 721 722<div style="margin: auto;"> 723 <h4><a name="brightness-contrast" 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> 724</div> 725 726<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> 727 728<p>Brightness and Contrast values apply changes to the input image. They are not absolute settings. A brightness or contrast value of zero means no change. The range of values is -100 to +100 on each. Positive values increase the brightness or contrast and negative values decrease the brightness or contrast. To control only contrast, set the brightness=0. To control only brightness, set contrast=0 or just leave it off.</p> 729 730<p>You may also use <a href="#fill">-channel</a> to control which channels to apply the brightness and/or contrast change. The default is to apply the same transformation to all channels.</p> 731 732<p>Brightness and Contrast arguments are converted to offset and slope of a linear transform and applied using <a href="#fill">-function polynomial "slope,offset"</a>.</p> 733 734<p>The slope varies from 0 at contrast=-100 to almost vertical at contrast=+100. For brightness=0 and contrast=-100, the result are totally midgray. For brightness=0 and contrast=+100, the result will approach but not quite reach a threshold at midgray; that is the linear transformation is a very steep vertical line at mid gray.</p> 735 736<p>Negative slopes, i.e. negating the image, are not possible with this function. All achievable slopes are zero or positive.</p> 737 738<p>The offset varies from -0.5 at brightness=-100 to 0 at brightness=0 to +0.5 at brightness=+100. Thus, when contrast=0 and brightness=100, the result is totally white. Similarly, when contrast=0 and brightness=-100, the result is totally black.</p> 739 740<p>As the range of values for the arguments are -100 to +100, adding the '%' symbol is no different than leaving it off.</p> 741 742<div style="margin: auto;"> 743 <h4><a name="cache" id="cache"></a>-cache <em class="arg">threshold</em></h4> 744</div> 745 746<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> 747 748<div style="margin: auto;"> 749 <h4><a name="caption" id="caption"></a>-caption <em class="arg">string</em></h4> 750</div> 751 752<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> 753 754<p>This option sets the caption meta-data of an image read in after this 755option has been given. To modify a caption of images already in memory use 756"<kbd><a href="#set">-set</a> caption</kbd>". </p> 757 758<p>The caption can contain special format characters listed in the <a 759href="/www/escape.html">Format and 760Print Image Properties</a>. These attributes are expanded when the caption 761is finally assigned to the individual images. </p> 762 763<p>If the first character of <em class="arg">string</em> is <em 764class="arg">@</em>, the image caption is read from a file titled by the 765remaining characters in the string. Comments read in from a file are literal; 766no embedded formatting characters are recognized.</p> 767 768<p>Caption meta-data ais not visible on the image itself. To do that use the 769<a href="#annotate">-annotate</a> or <a href="#draw">-draw</a> options 770instead.</p> 771 772<p>For example,</p> 773 774<p class="crtsnip"> 775 -caption "%m:%f %wx%h" bird.miff 776</p> 777 778<p>produces an image caption of <kbd>MIFF:bird.miff 512x480</kbd> (assuming 779that the image <kbd>bird.miff</kbd> has a width of 512 and a height of 780480.</p> 781 782 783<div style="margin: auto;"> 784 <h4><a name="cdl" id="cdl"></a>-cdl <em class="arg">filename</em></h4> 785</div> 786 787<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> 788 789<p>Here is an example color correction collection:</p> 790 791<pre class="text"> 792<?xml version="1.0" encoding="UTF-8"?> 793<ColorCorrectionCollection xmlns="urn:ASC:CDL:v1.2"> 794 <ColorCorrection id="cc06668"> 795 <SOPNode> 796 <Slope> 0.9 1.2 0.5 </Slope> 797 <Offset> 0.4 -0.5 0.6 </Offset> 798 <Power> 1.0 0.8 1.5 </Power> 799 </SOPNode> 800 <SATNode> 801 <Saturation> 0.85 </Saturation> 802 </SATNode> 803 </ColorCorrection> 804</ColorCorrectionCollection> 805</pre> 806 807<div style="margin: auto;"> 808 <h4><a name="channel" id="channel"></a>-channel <em class="arg">type</em></h4> 809</div> 810 811<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> 812 813<p>Choose from: <kbd>Red</kbd>, <kbd>Green</kbd>, <kbd>Blue</kbd>, <kbd>Alpha</kbd>, <kbd>Cyan</kbd>, <kbd>Magenta</kbd>, <kbd>Yellow</kbd>, <kbd>Black</kbd>, <kbd>Opacity</kbd>, <kbd>Index</kbd>, <kbd>RGB</kbd>, <kbd>RGBA</kbd>, <kbd>CMYK</kbd>, or <kbd>CMYKA</kbd>.</p> 814 815<p>The channels above can also be specified as a comma-separated list or can be 816abbreviated as a concatenation of the letters '<kbd>R</kbd>', '<kbd>G</kbd>', 817'<kbd>B</kbd>', '<kbd>A</kbd>', '<kbd>O</kbd>', '<kbd>C</kbd>', 818'<kbd>M</kbd>', '<kbd>Y</kbd>', '<kbd>K</kbd>'. 819 820For example, to only select the <kbd>Red</kbd> and <kbd>Blue</kbd> channels 821you can either use </p> 822<p class="crtsnip"> 823 -channel Red,Blue 824</p> 825<p>or you can use the short hand form</p> 826<p class="crtsnip"> 827 -channel RB 828</p> 829 830<p>All the channels that is present in an image can be specified using the 831special channel type <kbd>All</kbd>. Not all operators are 'channel capable', 832but generally any operators that are generally 'grey-scale' image operators, 833will understand this setting. See individual operator documentation. </p> 834 835<br> 836 837<p>On top of the normal channel selection a extra flag can be specified, 838'<kbd>Sync</kbd>'. This is turned on by default and if set means that 839operators that understand this flag should perform: cross-channel 840syncronization of the channels. If not specified, then most grey-scale 841operators will apply their image processing operations to each individual 842channel (as specified by the rest of the <a href="#channel">-channel</a> 843setting) completely independently from each other. </p> 844 845<p>For example for operators such as <a href="#auto-level">-auto-level</a> and 846<a href="#auto-gamma">-auto-gamma</a> the color channels are modified 847together in exactly the same way so that colors will remain in-sync. Without 848it being set, then each channel is modified separately and 849independently, which may produce color distortion. </p> 850 851<p>The <a href="#morphology">-morphology</a> '<kdb>Convolve</kdb>' method 852and the <a href="#compose">-compose</a> mathematical methods, also understands 853the '<kbd>Sync</kbd>' flag to modify the behaviour of pixel colors according 854to the alpha channel (if present). That is to say it will modify the image 855processing with the understanding that fully-transparent colors should not 856contribute to the final result. </p> 857 858Basically, by default, operators work with color channels in syncronous, and 859treats transparency as special, unless the <a href="#channel">-channel</a> 860setting is modified so as to remove the effect of the '<kbd>Sync</kbd>' flag. 861How each operator does this depends on that operators current implementation. 862Not all operators understands this flag at this time, but that is changing. 863</p> 864 865<p>To print a complete list of channel types, use <a href="#list">-list 866channel</a>.</p> 867 868<br> 869 870<p>By default, ImageMagick sets <a href="#channel">-channel</a> to the value 871'<kbd>RGBK,sync</kbd>', which specifies that operators act on all color 872channels except the transparency channel, and that all the color channels are 873to be modified in exactly the same way, with a understanding of transprancy 874(depending on the operation being applied). The 'plus' form <a 875href="#channel" >+channel</a> will reset the value back to this default. </p> 876 877<p>Options that are affected by the <a href="#channel" >-channel</a> setting 878include the following. 879 880<a href="#auto-gamma">-auto-gamma</a>, 881<a href="#auto-level">-auto-level</a>, 882<a href="#black-threshold">-black-threshold</a>, 883<a href="#blur">-blur</a>, 884<a href="#clamp">-clamp</a>, 885<a href="#clut">-clut</a>, 886<a href="#combine">-combine</a>, 887<a href="#composite">-composite</a> (Mathematical compose methods only), 888<a href="#convolve">-convolve</a>, 889<a href="#contrast-stretch">-contrast-stretch</a>, 890<a href="#evaluate">-evaluate</a>, 891<a href="#function">-function</a>, 892<a href="#fx">-fx</a>, 893<a href="#gaussian-blur">-gaussian-blur</a>, 894<a href="#hald-clut">-hald-clut</a>, 895<a href="#motion-blur">-motion-blur</a>, 896<a href="#morphology">-morphology</a>, 897<a href="#negate">-negate</a>, 898<a href="#normalize">-normalize</a>, 899<a href="#ordered-dither">-ordered-dither</a>, 900<a href="#radial-blur">-radial-blur</a>, 901<a href="#random-threshold">-random-threshold</a>, 902<a href="#separate">-separate</a>, 903<a href="#threshold">-threshold</a>, and 904<a href="#white-threshold">-white-threshold</a>. 905</p> 906 907<p>Warning, some operators behave differently when the <a href="#channel" 908>+channel</a> default setting is in effect, verses ANY user defined <a 909href="#channel" >-channel</a> setting (including the equivalent of the 910default). These operators have yet to be made to understand the newer 'Sync' 911flag. </p> 912 913<p>For example <a href="#threshold">-threshold</a> will by default gray-scale 914the image before thresholding, if no <a href="#channel" >-channel</a> setting 915has been defined. This is not 'Sync flag controlled, yet. </p> 916 917<p>Also some operators such as <a href="#blur">-blur</a>, <a 918href="#gaussian-blur">-gaussian-blur</a>, will modify their handling of the 919color channels if the '<kbd>alpha</kbd>' channel is also enabled by <a 920href="#channel" >-channel</a>. Generally this done to ensure that 921fully-transparent colors are treated as being fully-transparent, and thus any 922underlying 'hidden' color has no effect on the final results. Typically 923resulting in 'halo' effects. The newer <a href="#morphology">-morphology</a> 924convolution equivalents however does have a understanding of the 'Sync' flag 925and will thus handle transparency correctly by default. </p> 926 927<p>As a alpha channel is optional within images, some operators will read the 928color channels of an image as a greyscale alpha mask, when the image has no 929alpha channel present, and the <a href="#channel" >-channel</a> setting tells 930the operator to apply the operation using alpha channels. The <a 931href="#clut">-clut</a> operator is a good example of this. </p> 932 933 934<div style="margin: auto;"> 935 <h4><a name="clamp" id="clamp"></a>-clamp</h4> 936</div> 937 938<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> 939 940<div style="margin: auto;"> 941 <h4><a name="charcoal" id="charcoal"></a>-charcoal <em class="arg">factor</em></h4> 942</div> 943 944<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> 945 946<div style="margin: auto;"> 947 <h4><a name="chop" id="chop"></a>-chop <em class="arg">geometry</em></h4> 948</div> 949 950<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> 951 952<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> and <em class="arg">height</em> given in the of the <em class="arg">size</em> portion of the <em class="arg">geometry</em> argument give the number of columns and rows to remove. The <em class="arg">offset</em> portion of the <em class="arg">geometry</em> argument is influenced by a <a href="#gravity">-gravity</a> setting, if present.</p> 953 954<p>The <a href="#chop">-chop</a> option removes entire rows and columns, and moves the remaining corner blocks leftward and upward to close the gaps.</p> 955 956<div style="margin: auto;"> 957 <h4><a name="clip" id="clip"></a>-clip</h4> 958</div> 959 960<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> 961 962<p>If a clipping path is present, it is applied to subsequent operations.</p> 963 964<p>For example, in the command</p> 965 966<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -clip -negate cockatoo.tif negated.tif</span></p> 967<p>only the pixels within the clipping path are negated.</p> 968 969<p>The <a href="#clip">-clip</a> feature requires the XML library. If the XML library is not present, the option is ignored.</p> 970 971<div style="margin: auto;"> 972 <h4><a name="clip-mask" id="clip-mask"></a>-clip-mask</h4> 973</div> 974 975<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> 976 977<div style="margin: auto;"> 978 <h4><a name="clip-path" id="clip-path"></a>-clip-path <em class="arg">id</em></h4> 979</div> 980 981<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> 982 983<div style="margin: auto;"> 984 <h4><a name="clone" id="clone"></a>-clone <em class="arg">index(s)</em></h4> 985</div> 986 987<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Make a copy of an image (or images).</td><td style='text-align:right;'></td></tr></table> 988 989<p>Specify the image by its index in the sequence. The first image is index 9900. Negative indexes are relative to the end of the sequence; for example, −1 991represents the last image of the sequence. Specify a range of images with a 992dash (e.g. 0−4). Separate multiple indexes with commas but no spaces (e.g. 0,2,5). Use <a 993href="#clone">+clone</a> make a copy of the last image in the image 994sequence.</p> 995 996<div style="margin: auto;"> 997 <h4><a name="clut" id="clut"></a>-clut</h4> 998</div> 999 1000<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 1001corresponding channel in the second image as a <b>c</b>olor 1002<b>l</b>ook<b>u</b>p <b>t</b>able.</td><td style='text-align:right;'></td></tr></table> 1003 1004<p>The second (LUT) image is ordinarily a gradient image containing the 1005histogram mapping of how each channel should be modified. Typically it is a 1006either a single row or column image of replacement color values. If larger 1007than a single row or column, values are taken from a diagonal line from 1008top-left to bottom-right corners.</p> 1009 1010<p>The lookup is further controlled by the <a 1011href="#interpolate">-interpolate</a> setting, which is especially handy for an 1012LUT which is not the full length needed by the ImageMagick installed Quality 1013(Q) level. Good settings for this are the '<kbd>bilinear</kbd>' and 1014'<kbd>bicubic</kbd>' interpolation settings, which give smooth color 1015gradients, and the '<kbd>integer</kbd>' setting for a direct, unsmoothed 1016lookup of color values. </p> 1017 1018<p>This operator is especially suited to replacing a grayscale image with a 1019specific color gradient from the CLUT image. </p> 1020 1021<p>Only the channel values defined by the <a href="#channel">-channel</a> 1022setting will have their values replaced. In particular, since the default <a 1023href="#channel">-channel</a> setting is <kbd>RGB</kbd>, this means that 1024transparency (alpha/matte channel) is not affected, unless the <a 1025href="#channel">-channel</a> setting is modified. When the alpha channel is 1026set, it is treated by the <a href="#clut" >-clut</a> operator in the same way 1027as the other channels, implying that alpha/matte values are replaced using the 1028alpha/matte values of the original image. </p> 1029 1030<p>If either the image being modified, or the lookup image, contains no 1031transparency (i.e. <a href="#alpha" >-alpha</a> is turned 'off') but the <a 1032href="#channel">-channel</a> setting includes alpha replacement, then it is 1033assumed that image represents a gray-scale gradient which is used for the 1034replacement alpha values. That is you can use a gray-scale CLUT image to 1035adjust a existing images alpha channel, or you can color a gray-scale image 1036using colors form CLUT containing the desired colors, including transparency. 1037</p> 1038 1039<p>See also <a href="#hald-clut" >-hald-clut</a> which replaces colors according 1040the lookup of the full color RGB value from a 2D representation of a 3D color 1041cube. </p> 1042 1043 1044<div style="margin: auto;"> 1045 <h4><a name="coalesce" id="coalesce"></a>-coalesce</h4> 1046</div> 1047 1048<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> 1049 1050<p>Overlay each image in an image sequence according to its <a href="#dispose">-dispose</a> meta-data, to reproduce the look of an animation at each point in the animation sequence. All images should be the same size, and are assigned appropriate GIF disposal settings for the animation to continue working as expected as a GIF animation. Such frames are more easily viewed and processed than the highly optimized GIF overlay images. </p> 1051 1052<p>The animation can be re-optimized after processing using the <a href="#layers">-layers</a> method '<kbd>optimize</kbd>', though there is no guarantee that the restored GIF animation optimization is better than the original. </p> 1053 1054 1055<div style="margin: auto;"> 1056 <h4><a name="colorize" id="colorize"></a>-colorize <em class="arg">value</em></h4> 1057</div> 1058 1059<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> 1060 1061<p>Specify the amount of colorization as a percentage. Separate colorization values can be applied to the red, green, and blue channels of the image with a comma-delimited list of colorization values (e.g., <kbd>-colorize 0,0,50</kbd>).</p> 1062 1063<div style="margin: auto;"> 1064 <h4><a name="colormap" id="colormap"></a>-colormap <em class="arg">type</em></h4> 1065</div> 1066 1067<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> 1068 1069<p>The <em class="arg">type</em> can be <kbd>shared</kbd> or <kbd>private</kbd>.</p> 1070 1071<p>This option only applies when the default X server visual is <kbd>PseudoColor</kbd> or <kbd>GrayScale</kbd>. Refer to <a href="#visual">-visual</a> for more details. By default, a shared colormap is allocated. The image shares colors with other X clients. Some image colors could be approximated, therefore your image may look very different than intended. If <kbd>private</kbd> is chosen, the image colors appear exactly as they are defined. However, other clients may go <em>technicolor</em> when the image colormap is installed.</p> 1072 1073<div style="margin: auto;"> 1074 <h4><a name="colors" id="colors"></a>-colors <em class="arg">value</em></h4> 1075</div> 1076 1077<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> 1078 1079<p>The actual number of colors in the image may be less than your request, but never more. Note that this a color reduction option. Images with fewer unique colors than specified by <em class="arg">value</em> will have any duplicate or unused colors removed. The ordering of an existing color palette may be altered. When converting an image from color to grayscale, it is more efficient to convert the image to the gray colorspace before reducing the number of colors. Refer to the <a href="/www/quantize.html">color reduction algorithm</a> for more details.</p> 1080 1081<div style="margin: auto;"> 1082 <h4><a name="color-matrix" id="color-matrix"></a>-color-matrix <em class="arg">matrix</em></h4> 1083</div> 1084 1085<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> 1086 1087<p>This option permits saturation changes, hue rotation, luminance to alpha, and various other effects. Although variable-sized transformation matrices can be used, typically one uses a 5x5 matrix for an RGBA image and a 6x6 for CMYKA (or RGBA with offsets). The matrix is similar to those used by Adobe Flash except offsets are in column 6 rather than 5 (in support of CMYKA images) and offsets are normalized (divide Flash offset by 255).</p> 1088 1089<p>As an example, to add contrast to an image with offsets, try this command:</p> 1090 1091<pre class="text"> 1092convert kittens.jpg -color-matrix \ 1093 " 1.5 0.0 0.0 0.0, 0.0, -0.157 \ 1094 0.0 1.5 0.0 0.0, 0.0, -0.157 \ 1095 0.0 0.0 1.5 0.0, 0.0, -0.157 \ 1096 0.0 0.0 0.0 1.0, 0.0, 0.0 \ 1097 0.0 0.0 0.0 0.0, 1.0, 0.0 \ 1098 0.0 0.0 0.0 0.0, 0.0, 1.0" kittens.png 1099</pre> 1100<div style="margin: auto;"> 1101 <h4><a name="colorspace" id="colorspace"></a>-colorspace <em class="arg">value</em></h4> 1102</div> 1103 1104<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> 1105 1106<p>Choices are:</p> 1107 1108<pre class="text"> 1109 CMY 1110 CMYK 1111 Gray 1112 HSB 1113 HSL 1114 HWB 1115 Lab 1116 Log 1117 OHTA 1118 Rec601Luma 1119 Rec601YCbCr 1120 Rec709Luma 1121 Rec709YCbCr 1122 RGB 1123 sRGB 1124 Transparent 1125 XYZ 1126 YCbCr 1127 YCC 1128 YIQ 1129 YPbPr 1130 YUV 1131</pre> 1132 1133<p>To print a complete list of colorspaces, use <a href="#list">-list colorspace</a>.</p> 1134 1135<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> 1136 1137<table class="doc"> 1138 <caption>Conversion Of RGB To Other Color Spaces</caption> 1139 <tr><th align="left" valign="middle">CMY</th></tr> 1140 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>−R</td></tr> 1141 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>−G</td></tr> 1142 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>−B</td></tr> 1143 <tr><th align="left" valign="middle">CMYK — starts with CMY from above</th></tr> 1144 <tr><td align="left" valign="middle">K=min(C,Y,M)</td></tr> 1145 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>*(C−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 1146 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>*(M−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 1147 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>*(Y−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 1148 1149 <tr><th align="left" valign="middle">Gray</th></tr> 1150 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr> 1151 1152 <tr><th align="left" valign="middle">HSB — Hue, Saturation, Brightness; like a cone peak downward</th></tr> 1153 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr> 1154 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr> 1155 <tr><td align="left" valign="middle">B=distance along axis from bottom upward; B=max(R,G,B); <em>intensity-like</em></td></tr> 1156 1157 <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> 1158 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr> 1159 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr> 1160 <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> 1161 1162 <tr><th align="left" valign="middle">HWB — Hue, Whiteness, Blackness</th></tr> 1163 <tr><td align="left" valign="middle">Hue (complicated equation)</td></tr> 1164 <tr><td align="left" valign="middle">Whiteness (complicated equation)</td></tr> 1165 <tr><td align="left" valign="middle">Blackness (complicated equation)</td></tr> 1166 1167 <tr><th align="left" valign="middle">LAB</th></tr> 1168 <tr><td align="left" valign="middle">L (complicated equation relating X,Y,Z)</td></tr> 1169 <tr><td align="left" valign="middle">A (complicated equation relating X,Y,Z)</td></tr> 1170 <tr><td align="left" valign="middle">B (complicated equation relating X,Y,Z)</td></tr> 1171 1172 <tr><th align="left" valign="middle">LOG</th></tr> 1173 <tr><td align="left" valign="middle">I1 (complicated equation involving logarithm of R)</td></tr> 1174 <tr><td align="left" valign="middle">I2 (complicated equation involving logarithm of G)</td></tr> 1175 <tr><td align="left" valign="middle">I3 (complicated equation involving logarithm of B)</td></tr> 1176 1177 <tr><th align="left" valign="middle">OHTA — approximates principal components transformation</th></tr> 1178 <tr><td align="left" valign="middle">I1=0.33333*R+0.33334*G+0.33333*B; <em>intensity-like</em></td></tr> 1179 <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> 1180 <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> 1181 1182 <tr><th align="left" valign="middle">Rec601Luma</th></tr> 1183 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr> 1184 1185 <tr><th align="left" valign="middle">Rec601YCbCr</th></tr> 1186 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1187 <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> 1188 <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> 1189 1190 <tr><th align="left" valign="middle">Rec709Luma</th></tr> 1191 <tr><td align="left" valign="middle">Gray=0.21260*R+0.71520*G+0.07220*B</td></tr> 1192 1193 <tr><th align="left" valign="middle">Rec709YCbCr</th></tr> 1194 <tr><td align="left" valign="middle">Y=0.212600*R+0.715200*G+0.072200*B; <em>intensity-like</em></td></tr> 1195 <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> 1196 <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> 1197 1198 <tr><th align="left" valign="middle">sRGB</th></tr> 1199 <tr><td align="left" valign="middle">if Rs ≤ .03928 then Rs=R/12.92 else Rs=((R+.055)/1.055)^2.4</td></tr> 1200 <tr><td align="left" valign="middle">if Gs ≤ .03928 then Gs=B/12.92 else Gs=((G+.055)/1.055)^2.4</td></tr> 1201 <tr><td align="left" valign="middle">if Bs ≤ .03928 then Bs=B/12.92 else Bs=((B+.055)/1.055)^2.4</td></tr> 1202 1203 <tr><th align="left" valign="middle">XYZ</th></tr> 1204 <tr><td align="left" valign="middle">X=0.4124240*R+0.3575790*G+0.1804640*B</td></tr> 1205 <tr><td align="left" valign="middle">Y=0.2126560*R+0.7151580*G+0.0721856*B</td></tr> 1206 <tr><td align="left" valign="middle">Z=0.0193324*R+0.1191930*G+0.9504440*B</td></tr> 1207 1208 <tr><th align="left" valign="middle">YCC</th></tr> 1209 <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> 1210 <tr><td align="left" valign="middle">C1=(−0.29900*R−0.58700*G+0.88600*B) (with complicated scaling)</td></tr> 1211 <tr><td align="left" valign="middle">C2=(0.70100*R−0.58700*G−0.11400*B) (with complicated scaling)</td></tr> 1212 1213 <tr><th align="left" valign="middle">YCbCr</th></tr> 1214 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1215 <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> 1216 <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> 1217 1218 <tr><th align="left" valign="middle">YIQ</th></tr> 1219 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr> 1220 <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> 1221 <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> 1222 1223 <tr><th align="left" valign="middle">YPbPr</th></tr> 1224 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1225 <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> 1226 <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> 1227 1228 <tr><th align="left" valign="middle">YUV</th></tr> 1229 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr> 1230 <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> 1231 <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> 1232</table> 1233 1234<div style="margin: auto;"> 1235 <h4><a name="combine" id="combine"></a>-combine</h4> 1236</div> 1237 1238<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> 1239 1240<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> 1241 1242<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. 1243</p> 1244 1245<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> 1246<div style="margin: auto;"> 1247 <h4><a name="comment" id="comment"></a>-comment <em class="arg">string</em></h4> 1248</div> 1249 1250<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> 1251 1252<p>This option sets the comment meta-data of an image read in after this 1253option has been given. To modify a comment of images already in memory use 1254"<kbd><a href="#set">-set</a> comment</kbd>". </p> 1255 1256<p>The comment can contain special format characters listed in the <a 1257href="/www/escape.html">Format and 1258Print Image Properties</a>. These attributes are expanded when the comment 1259is finally assigned to the individual images. </p> 1260 1261<p>If the first character of <em class="arg">string</em> is <em 1262class="arg">@</em>, the image comment is read from a file titled by the 1263remaining characters in the string. Comments read in from a file are literal; 1264no embedded formatting characters are recognized.</p> 1265 1266<p>Comment meta-data are not visible on the image itself. To do that use the 1267<a href="#annotate">-annotate</a> or <a href="#draw">-draw</a> options 1268instead.</p> 1269 1270<p>For example,</p> 1271 1272<p class="crtsnip"> 1273 -comment "%m:%f %wx%h" bird.miff 1274</p> 1275 1276<p>produces an image comment of <kbd>MIFF:bird.miff 512x480</kbd> (assuming 1277that the image <kbd>bird.miff</kbd> has a width of 512 and a height of 1278480.</p> 1279 1280<div style="margin: auto;"> 1281 <h4><a name="compose" id="compose"></a>-compose <em class="arg">operator</em></h4> 1282</div> 1283 1284<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> 1285 1286<p>See <a href="/www/compose.html">Alpha Compositing</a> for 1287a detailed discussion of alpha compositing.</p> 1288 1289<p>This setting effects image processing operators that merge two (or more) 1290images together in some way. This includes the operators, 1291<a href="#composite">-composite</a>, 1292<a href="#layers">-layers</a> composite, 1293<a href="#flatten">-flatten</a>, 1294<a href="#mosaic">-mosaic</a>, 1295<a href="#layers">-layers</a> merge, 1296<a href="#border">-border</a>, 1297<a href="#frame">-frame</a>, 1298and <a href="#extent">-extent</a>. </p> 1299 1300<p>It is also one of the primary options for the "<kbd>composite</kbd>" 1301command. </p> 1302 1303 1304<div style="margin: auto;"> 1305 <h4><a name="composite" id="composite"></a>-composite</h4> 1306</div> 1307 1308<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> 1309 1310<p>Take the first image 'destination' and overlay the second 'source' image 1311according to the current <a href="#compose">-compose</a> setting. The location 1312of the 'source' or 'overlay' image is controlled according to <a 1313href="#geometry" >-geometry</a>, and <a href="#geometry" >-geometry</a> 1314settings. </p> 1315 1316<p>If a third image is given this is treated as a gray-scale 'mask' image 1317relative to the first 'destination' image. This mask will limit what parts of 1318the destination can be modified by the image composition. However for the 1319'<kbd>displace</kbd>' compose method, the mask is used to provide a separate 1320Y-displacement image instead. </p> 1321 1322<p>If a <a href="#compose">-compose</a> method requires extra numerical 1323arguments or flags these can be provided by setting the <a 1324href="#set">-set</a> '<kbd class="arg">option:compose:args</kbd>' 1325appropriately for the compose method. </p> 1326 1327<p>Some <a href="#compose">-compose</a> methods can modify the 'destination' 1328image outside the overlay area. You can disable this by setting the special <a 1329href="#set">-set</a> '<kbd class="arg">option:compose:outside-overlay</kbd>' 1330to '<kbd>false</kbd>'. </p> 1331 1332 1333<div style="margin: auto;"> 1334 <h4><a name="compress" id="compress"></a>-compress <em class="arg">type</em></h4> 1335</div> 1336 1337<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> 1338 1339<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> 1340 1341<p>To print a complete list of compression types, use <a href="#list">-list compress</a>.</p> 1342 1343<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> 1344 1345<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> 1346 1347<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> 1348 1349<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> 1350 1351<div style="margin: auto;"> 1352 <h4><a name="contrast" id="contrast"></a>-contrast</h4> 1353</div> 1354 1355<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> 1356 1357<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> 1358 1359<p>For a more pronounced effect you can repeat the option:</p> 1360 1361<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -contrast -contrast rose_c2.png</span></p> 1362<div style="margin: auto;"> 1363 <h4><a name="contrast-stretch" 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> 1364</div> 1365 1366<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> 1367 1368<p>While performing the stretch, black-out at most <em 1369class="arg" >black-point</em> pixels and white-out at most <em 1370class="arg" >white-point</em> pixels. Or, if percent is used, black-out at most 1371<em class="arg" >black-point %</em> pixels and white-out at most <em 1372class="arg" >white-point %</em> pixels.</p> 1373 1374<p>Prior to ImageMagick 6.4.7-0, <a href="#contrast-stretch" 1375>-contrast-stretch</a> will black-out at most <em class="arg" 1376>black-point</em> pixels and white-out at most <em class="arg" >total pixels 1377minus white-point</em> pixels. Or, if percent is used, black-out at most <em 1378class="arg">black-point %</em> pixels and white-out at most <em class="arg" 1379>100% minus white-point %</em> pixels.</p> 1380 1381<p>Note that <kbd>-contrast-stretch 0</kbd> will modify the image such that 1382the image's min and max values are stretched to 0 and <em class="QR" 1383>QuantumRange</em>, respectively, without any loss of data due to burn-out or 1384clipping at either end. This is not the same as <a href="#normalize" 1385>-normalize</a>, which is equivalent to <kbd>-contrast-stretch 0.15x0.05%</kbd> (or 1386prior to ImageMagick 6.4.7-0, <kbd>-contrast-stretch 2%x99%</kbd>).</p> 1387 1388<p>Internally operator works by creating a histogram bin, and then uses that 1389bin to modify the image. As such some colors may be merged together when they 1390originally fell into the same 'bin'. </p> 1391 1392<p>All the channels are normalized in concert by the came amount so as to 1393preserve color integrity, when the default <a href="#channel" >+channel</a> 1394setting is in use. Specifying any other <a href="#channel" >-channel</a> 1395setting will normalize the RGB channels independently.</p> 1396 1397<p>See also <a href="#auto-level" >-auto-level</a> for a 'perfect' 1398normalization of mathematical images. </p> 1399 1400<p>This operator is under review for re-development. </p> 1401 1402 1403<div style="margin: auto;"> 1404 <h4><a name="convolve" id="convolve"></a>-convolve <em class="arg">kernel</em></h4> 1405</div> 1406 1407<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> 1408 1409<p>The <em class="arg">kernel</em> is a matrix specified as 1410a comma-separated list of integers (with no spaces), ordered left-to right, 1411starting with the top row. Presently, only odd-dimensioned kernels are 1412supported, and therefore the number of entries in the specified <em 1413class="arg">kernel</em> must be 3<sup>2</sup>=9, 5<sup>2</sup>=25, 14147<sup>2</sup>=49, etc. </p> 1415 1416<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 1417positive and negative results are relative to a user-specified bias value. 1418This is important for non-HDRI compilations of ImageMagick when dealing with 1419convolutions that contain negative as well as positive values. This is 1420especially the case with convolutions involving high pass filters or edge 1421detection. Without an output bias, the negative values is clipped at zero. 1422</p> 1423 1424<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 1425negative results without clipping to the color value range (0..QuantumRange). 1426See the discussion on HDRI implementations of ImageMagick on the page <a 1427href="/www/high-dynamic-range.html">High 1428Dynamic-Range Images</a>. For more about HDRI go the ImageMagick <a 1429href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this 1430<a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a> 1431entry. </p> 1432 1433 1434<div style="margin: auto;"> 1435 <h4><a name="crop" id="crop"></a>-crop <em class="arg">geometry</em></h4> 1436</div> 1437 1438<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> 1439 1440<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> 1441 1442<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> 1443 1444<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> 1445 1446<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> 1447 1448<p>By adding a exclamation character flag to the geometry argument, the 1449cropped images virtual canvas page size and offset is set as if the 1450geometry argument was a viewport or window. This means the canvas page size 1451is set to exactly the same size you specified, the image offset set 1452relative top left corner of the region cropped. </p> 1453 1454<p>If the cropped image 'missed' the actual image on its virtual canvas, a 1455special single pixel transparent 'missed' image is returned, and a 'crop 1456missed' warning given. </p> 1457 1458<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> 1459 1460<div style="margin: auto;"> 1461 <h4><a name="cycle" id="cycle"></a>-cycle <em class="arg">amount</em></h4> 1462</div> 1463 1464<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> 1465 1466<p><em class="arg">Amount</em> defines the number of positions each 1467colormap entry is shifted.</p> 1468 1469 1470<div style="margin: auto;"> 1471 <h4><a name="debug" id="debug"></a>-debug <em class="arg">events</em></h4> 1472</div> 1473 1474<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> 1475 1476<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> 1477 1478 1479<p>For example, to log cache and blob events, use.</p> 1480 1481<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -debug "Cache,Blob" rose: rose.png</span></p> 1482<p>The <kbd>User</kbd> domain is normally empty, but developers can log user events in their private copy of ImageMagick.</p> 1483 1484<p>To print the complete list of debug methods, use <a href="#list">-list debug</a>.</p> 1485 1486<p>Use the <a href="#log">-log</a> option to specify the format for debugging output.</p> 1487 1488<p>Use <a href="#debug">+debug</a> to turn off all logging.</p> 1489 1490<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> 1491 1492 1493<div style="margin: auto;"> 1494 <h4><a name="decipher" id="decipher"></a>-decipher <em class="arg">filename</em></h4> 1495</div> 1496 1497<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> 1498 1499<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p> 1500 1501<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p> 1502 1503 1504<div style="margin: auto;"> 1505 <h4><a name="deconstruct" id="deconstruct"></a>-deconstruct</h4> 1506</div> 1507 1508<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> 1509 1510<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> 1511 1512<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> 1513 1514<p>This option is actually equivalent to the <a href="#layers">-layers</a> method '<kbd>compare-any</kbd>'. </p> 1515 1516 1517<div style="margin: auto;"> 1518 <h4><a name="define" id="define"></a>-define <em class="arg">key</em>{<em class="arg">=value</em>}<em class="arg">...</em></h4> 1519</div> 1520 1521<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 1522coders and image processing operations.</td><td style='text-align:right;'></td></tr></table> 1523 1524<p>This option creates one or more definitions for coders and decoders to use 1525while reading and writing image data. Definitions are generally used to 1526control image file format coder modules, and image processing operations, 1527beyond what is provided by normal means. Defined settings are listed in <a 1528href="#verbose" >-verbose</a> information ("<kbd>info:</kbd>" output format) 1529as "Artifacts". </p> 1530 1531<p>If <em class="arg">value</em> is missing for a definition, an empty-valued 1532definition of a flag is created with that name. This used to control on/off 1533options. Use <a href="#define">+define key</a> to remove definitions 1534previously created. Use <a href="#define">+define "*"</a> to remove all 1535existing definitions.</p> 1536 1537<p>The same 'artifact' settings can also be defined using the <a 1538href="#set" >-set "option:<em class="arg">key</em>" "<em class="arg" 1539>value</em>"</a> option, which also allows the use of <a href="/www/escape.html" >Format and Print Image 1540Properties</a> in the defined value. </p> 1541 1542<p>Such settings are global in scope, and effect all images and operations. </p> 1543 1544<p>The following definitions are just some of the artifacts that are 1545available:</p> 1546 1547<ul> 1548 1549<dt>dcm:display-range=reset</dt> 1550<dd>Set the display range to the minimum and maximum pixel values for the 1551 DCM image format.</dd><br /> 1552 1553<dt>dot:layout-engine=<em class="arg">value</em></dt> 1554<dd>Set the specify the layout engine for the DOT image format (e.g. 1555 <kbd>neato</kbd>).</dd><br /> 1556 1557<dt>jpeg:extent=<em class="arg">value</em></dt> 1558<dd>Restrict the maximum JPEG file size, for example <kbd>-define 1559 jpeg:extent=400kb</kbd>.</dd><br /> 1560 1561<dt>jpeg:size=<em class="arg">geometry</em></dt> 1562<dd>Set the size hint of a JPEG image, for example, -define jpeg:size=128x128. 1563 It is most useful for increasing performance and reducing the memory 1564 requirements when reducing the size of a large JPEG image.</dd><br /> 1565 1566<dt>jp2:rate=<em class="arg">value</em></dt> 1567<dd>Specify the compression factor to use while writing JPEG-2000 files. The 1568 compression factor is the reciprocal of the compression ratio. The valid 1569 range is 0.0 to 1.0, with 1.0 indicating lossless compression. If defined, 1570 this value overrides the -quality setting. A quality setting of 75 1571 results in a rate value of 0.06641.</dd><br /> 1572 1573<dt>mng:need-cacheoff</dt> 1574 <dd>turn playback caching off for streaming MNG.</dd><br /> 1575 1576<dt>png:bit-depth=<em class="arg">value</em></dt> 1577<dt>png:color-type=<em class="arg">value</em></dt> 1578<dd>desired bit-depth and color-type for PNG output. You can force the PNG 1579 encoder to use a different bit-depth and color-type than it would have 1580 normally selected, but only if this does not cause any loss of image 1581 quality. Any attempt to reduce image quality is treated as an error and no 1582 PNG file is written. E.g., if you have a 1-bit black-and-white image, you 1583 can use these "defines" to cause it to be written as an 8-bit grayscale, 1584 indexed, or even a 64-bit RGBA. But if you have a 16-million color image, 1585 you cannot force it to be written as a grayscale or indexed PNG. If you 1586 wish to do this, you must use the appropriate <a href="#depth">-depth</a>, 1587 <a href="#colors">-colors</a>, or <a href="#type">-type</a> directives to 1588 reduce the image quality prior to using the PNG encoder. Note that in 1589 indexed PNG files, "bit-depth" refers to the number of bits per index, 1590 which can range from 1 to 8. In such files, the color samples always have 1591 8-bit depth.</dd><br /> 1592 1593<dt>ps:imagemask</dt> 1594<dd>If the ps:imagemask flag is defined, the PS3 and EPS3 coders will create 1595 Postscript files that render bilevel images with the Postscript imagemask 1596 operator instead of the image operator.</dd><br /> 1597 1598<dt>quantum:format=<em class="arg">type</em></dt> 1599<dd>Set the type to <kbd>floating-point</kbd> to specify a floating-point 1600 format for raw files (e.g. GRAY:) or for MIFF and TIFF images in HDRI mode 1601 to preserve negative values. If <a href="#depth">-depth</a> 16 is 1602 included, the result is a single precision floating point format. 1603 If <a href="#depth">-depth</a> 32 is included, the result is 1604 double precision floating point format.</dd> 1605 1606</ul> 1607 1608<p>For example, to create a postscript file that will render only the black 1609pixels of a bilevel image, use:</p> 1610 1611<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert bilevel.tif -define ps:imagemask eps3:stencil.ps</span></p> 1612<p>Set attributes of the image registry by prefixing the value with 1613<kbd>registry:</kbd>. For example, to set a temporary path to put work files, 1614use:</p> 1615 1616<p class="crtsnip"> 1617-define registry:temporary-path=/data/tmp 1618</p> 1619 1620 1621 1622<div style="margin: auto;"> 1623 <h4><a name="delay" 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> 1624</div> 1625 1626<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> 1627 1628<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> 1629 1630<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> 1631 1632 1633<div style="margin: auto;"> 1634 <h4><a name="delete" id="delete"></a>-delete <em class="arg">index</em></h4> 1635</div> 1636 1637<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> 1638 1639<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> 1640 1641 1642<div style="margin: auto;"> 1643 <h4><a name="density" id="density"></a>-density <em class="arg">width</em><br />-density <em class="arg">width</em>x<em class="arg">height</em></h4> 1644</div> 1645 1646<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> 1647 1648<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> 1649 1650<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> 1651 1652<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> 1653 1654<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> 1655 1656<div style="margin: auto;"> 1657 <h4><a name="depth" id="depth"></a>-depth <em class="arg">value</em></h4> 1658</div> 1659 1660<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> 1661 1662<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> 1663 1664<div style="margin: auto;"> 1665 <h4><a name="descend" id="descend"></a>-descend</h4> 1666</div> 1667 1668<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> 1669 1670<div style="margin: auto;"> 1671 <h4><a name="deskew" id="deskew"></a>-deskew <em class="arg">threshold</em></h4> 1672</div> 1673 1674<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> 1675 1676<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> 1677 1678<div style="margin: auto;"> 1679 <h4><a name="despeckle" id="despeckle"></a>-despeckle</h4> 1680</div> 1681 1682<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> 1683 1684<div style="margin: auto;"> 1685 <h4><a name="direction" id="direction"></a>-direction <em class="arg">type</em></h4> 1686</div> 1687 1688<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> 1689 1690<div style="margin: auto;"> 1691 <h4><a name="displace" 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> 1692</div> 1693 1694<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> 1695 1696<p>With this option, the 'overlay' image, and optionally the 'mask' image, 1697is used as a displacement map, which is used to displace the lookup of 1698what part of the 'background' image is seen at each point of the overlaid 1699area. Much like the displacement map is a 'lens' that redirects light shining 1700through it so as to present a distorted view the original 'background' image 1701behind it. </p> 1702 1703<p>Any perfect grey areas of the displacement map produce a zero 1704displacement of the image. Black areas produce the given maximum negative 1705displacement of the lookup point, while white produce a maximum positive 1706displacement of the lookup. </p> 1707 1708<p>Note that it is the lookup of the 'background' that is displaced, not a 1709displacement of the image itself. As such an area of the displacement map 1710containing 'white' will have the lookup point 'shifted' by a positive amount, 1711and thus generating a copy of the destination image to the right/downward from 1712the correct position. That is the image will look like it may have been 1713'shifted' in a negative left/upward direction. Understanding this is a very 1714important in understanding how displacement maps work. </p> 1715 1716<p>The given arguments define the maximum amount of displacement in pixels 1717that a particular map can produce. If the displacement scale is large enough 1718it is also possible to lookup parts of the 'background' image that lie well 1719outside the bounds of the displacement map itself. That is you could very 1720easily copy a section of the original image from outside the overlay area 1721into the overlay area. </p> 1722 1723<p>The '%' flag makes the displacement scale relative to the size of the 1724overlay image (100% = half width/height of image). Using '!' switches 1725percentage arguments to refer to the destination image size instead. 1726these flags were added as of IM v6.5.3-5.</p> 1727 1728<p>Normally a single grayscale displacement map is provided, which with the 1729given scaling values will determine a single direction (vector) in which 1730displacements can occur (positively or negatively). However, if you also 1731specify a third image which is normally used as a <em class="arg">mask</em>, 1732the <em class="arg">composite image</em> is used for horizontal X 1733displacement, while the <em class="arg">mask image</em> is used for vertical Y 1734displacement. This allows you to define completely different displacement 1735values for the X and Y directions, and allowing you to lookup any point within 1736the <em class="arg">scale</em> bounds. In other words each pixel can lookup 1737any other nearby pixel, producing complex 2 dimensional displacements, rather 1738than a simple 1 dimensional vector displacements. </p> 1739 1740<p>Alteratively rather than suppling two separate images, as of IM v6.4.4-0, 1741you can use the 'red' channel of the overlay image to specify the horizontal 1742or X displacement, and the 'green' channel for the vertical or Y displacement. 1743</p> 1744 1745<p>As of IM v6.5.3-5 any alpha channel in the overlay image is used as a 1746mask the transparency of the destination image. However areas outside the 1747overlaid areas will not be effected. </p> 1748 1749 1750<div style="margin: auto;"> 1751 <h4><a name="display" id="display"></a>-display <em class="arg">host:display[.screen]</em></h4> 1752</div> 1753 1754<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> 1755 1756<p>This option is used with convert for obtaining image or font from this X server. See <em class="arg">X(1)</em>.</p> 1757 1758<div style="margin: auto;"> 1759 <h4><a name="dispose" id="dispose"></a>-dispose <em class="arg">method</em></h4> 1760</div> 1761 1762<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> 1763 1764<p>The layer disposal method defines the way each the displayed image is to be 1765modified after the current 'frame' of an animation has finished being 1766displayed (after its 'delay' period), but before the next frame on an 1767animation is to be overlaid onto the display. </p> 1768 1769<p>Here are the valid methods:</p> 1770 1771<pre class="text"> 1772Undefined 0 No disposal specified (equivalent to '<kbd>none</kbd>'). 1773None 1 Do not dispose, just overlay next frame image. 1774Background 2 Clear the frame area with the background color. 1775Previous 3 Clear to the image prior to this frames overlay. 1776</pre> 1777 1778<p>You can also use the numbers given above, which is what the GIF format 1779uses internally to represent the above settings. </p> 1780 1781<p>To print a complete list of dispose methods, use <a href="#list">-list dispose</a>.</p> 1782 1783<p>Use <a href="#dispose" >+dispose</a>, turn off the setting and prevent 1784resetting the layer disposal methods of images being read in. </p> 1785 1786<p>Use <a href="#set">-set</a> '<kbd>dispose</kbd>' method to set the image 1787disposal method for images already in memory.</p> 1788 1789<div style="margin: auto;"> 1790 <h4><a name="dissimilarity-threshold" id="dissimilarity-threshold"></a>-dissimilarity-threshold <em class="arg">value</em></h4> 1791</div> 1792 1793<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> 1794 1795 1796<div style="margin: auto;"> 1797 <h4><a name="dissolve" id="dissolve"></a>-dissolve <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]</h4> 1798</div> 1799 1800<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> 1801 1802<p>The opacity of the composite image is multiplied by the given percent, then 1803it is composited 'over' the main image. If <em class="arg">src_percent</em> 1804is greater than 100, start dissolving the main image so it becomes 1805transparent at a value of '<kbd class="arg">200</kbd>'. If both percentages 1806are given, each image are dissolved to the percentages given. </p> 1807 1808<p>Note that dissolve percentages do not add, two opaque images dissolved 1809'50,50', produce a 75% transparency. For a 50% + 50% blending of the two 1810images, you would need to use dissolve values of '50,100'. </p> 1811 1812<div style="margin: auto;"> 1813 <h4><a name="distort" id="distort"></a>-distort <em class="arg">method arguments</em></h4> 1814</div> 1815 1816<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> 1817 1818<p>The <em class="arg">arguments</em> is a single string containing a list 1819of floating point numbers separated by commas or spaces. The number of 1820and meaning of the floating point values depends on the distortion <em 1821class="arg">method</em> being used. </p> 1822 1823<p>Choose from these distortion types:</p> 1824 1825<table class="doc"> 1826 <tr valign="top"> 1827 <th align="left" style="width: 8%">Method</th> 1828 <th align="left">Description</th> 1829 </tr> 1830 1831 <tr valign="top"> 1832 <td valign="top"><kbd>ScaleRotateTranslate</kbd> 1833 <br/>or <kbd>SRT</kbd></td> 1834 <td valign="top"> 1835 Distort image by first scaling and rotating about a given 'center', 1836 before translating that 'center' to the new location, in that order. It 1837 is an alternative method of specifying a '<kbd>Affine</kbd>' type of 1838 distortion, but without shearing effects. It also provides a good way 1839 of rotating and displacing a smaller image for tiling onto a larger 1840 background (IE 2-dimensional animations). <br/> 1841 1842 The number of arguments determine the specific meaning of each 1843 argument for the scales, rotation, and translation operations. <br/> 1844 1845 <table style="margin-left:auto; margin-right:auto;"> 1846 <tr><td># </td><td>arguments meaning</td></tr> 1847 <tr><td>1:</td><td><em>Angle_of_Rotation</em></td></tr> 1848 <tr><td>2:</td><td><em>Scale Angle</em></td></tr> 1849 <tr><td>3:</td><td><em>ScaleX,ScaleY Angle</em></td></tr> 1850 <tr><td>4:</td><td><em>X,Y Scale Angle</em></td></tr> 1851 <tr><td>5:</td> 1852 <td><em>X,Y ScaleX,ScaleY Angle</em></td></tr> 1853 <tr><td>6:</td> 1854 <td><em>X,Y Scale Angle NewX,NewY</em></td></tr> 1855 <tr><td>7:</td> 1856 <td><em>X,Y ScaleX,ScaleY Angle 1857 NewX,NewY</em></td></tr> 1858 </table> 1859 1860 This is actually an alternative way of specifying a 2 dimensional linear 1861 '<kbd>Affine</kbd>' or '<kbd>AffineProjection</kbd>' distortion. </td> </tr> 1862 1863 <tr valign="top"> 1864 <td valign="top"><kbd>Affine</kbd></td> 1865 <td valign="top"> 1866 Distort the image linearly by moving a list of at least 3 or more sets 1867 of control points (as defined below). Ideally 3 sets or 12 floating 1868 point values are given allowing the image to be linearly scaled, 1869 rotated, sheared, and translated, according to those three points. See 1870 also the related '<kbd>AffineProjection</kbd>' and '<kbd>SRT</kbd>' 1871 distortions. <br/> 1872 1873 More than 3 sets given control point pairs (12 numbers) is least 1874 squares fitted to best match a lineary affine distortion. If only 2 1875 control point pairs (8 numbers) are given a two point image translation 1876 rotation and scaling is performed, without any possible shearing, 1877 flipping or changes in aspect ratio to the resulting image. If only one 1878 control point pair is provides the image is only translated, (which may 1879 be a floating point non-integer translation). <br/> 1880 1881 This distortion does not include any form of perspective distortion. 1882 </td> 1883 1884 </tr> 1885 1886 <tr valign="top"> 1887 <td valign="top"><kbd>AffineProjection</kbd></td> 1888 <td valign="top"> 1889 Linearly distort an image using the given Affine Matrix of 6 1890 pre-calculated coefficients forming a set of Affine Equations to map 1891 the source image to the destination image. 1892 1893 <div style="text-align: center"><em> 1894 s<sub>x</sub>, r<sub>x</sub>, 1895 r<sub>y</sub>, s<sub>y</sub>, 1896 t<sub>x</sub>, t<sub>y</sub> 1897 </em></div> 1898 1899 See <a href="#affine" >-affine</a> setting for more detail, and 1900 meanings of these coefficients. <br/> 1901 1902 The distortions '<kbd>Affine</kbd>' and '<kbd>SRT</kbd>' provide 1903 alternative methods of defining this distortion, with ImageMagick doing 1904 the calculations needed to generate the required coefficients. You can 1905 see the internally generated coefficients, by using a <a 1906 href="#verbose" >-verbose</a> setting with those other varients. </td> 1907 1908 </tr> 1909 1910 <tr valign="top"> 1911 <td valign="top"><kbd>BilinearForward</kbd><br/> 1912 <kbd>BilinearReverse</kbd></td> 1913 <td valign="top"> 1914 Bilinear Distortion, given a minimum of 4 sets of coordinate pairs, or 1915 16 values (see below). Not that lines may not appear straight after 1916 distortion, though the distance between coordinates will remain 1917 consistent. <br/> 1918 1919 The '<kbd>BilinearForward</kbd>' is used to map rectangles to any 1920 quadrilateral, while the '<kbd>BilinearReverse</kbd>' form maps any 1921 quadrilateral to a rectangle, while preserving the straigth line edges 1922 in each case. <br/> 1923 1924 Note that '<kbd>BilinearForward</kbd>' can generate invalid pixels 1925 which will be colored using the <a href="#mattecolor" >-mattecolor</a> 1926 color setting. Also if the quadraterial becomes 'flipped' the image 1927 may dissappear. <br/> 1928 1929 There are future plans to produce a true Bilinear distortion that will 1930 attempt to map any quadrilateral to any other quadrilateral, while 1931 preserving edges (and edge distance ratios). 1932 1933 </td> 1934 </tr> 1935 1936 <tr valign="top"> 1937 <td valign="top"><kbd>Perspective</kbd></td> 1938 <td valign="top"> 1939 Perspective distort the images, using a list of 4 or more sets of 1940 control points (as defined below). More that 4 sets (16 numbers) of 1941 control points provide least squares fitting for more accurate 1942 distortions (for the purposes of image registration and panarama 1943 effects). Less than 4 sets will fall back to a '<kbd>Affine</kbd>' 1944 linear distortion. <br/> 1945 1946 Perspective Distorted images ensures that straight lines remain 1947 straight, but the scale of the distorted image will vary. The horizon 1948 is anti-aliased, and the 'sky' color may be set using the 1949 <a href="#mattecolor" >-mattecolor</a> setting. </td> 1950 </tr> 1951 1952 <tr valign="top"> 1953 <td valign="top"><kbd>PerspectiveProjection</kbd> </td> 1954 <td valign="top"> 1955 Do a '<kbd>Perspective</kbd>' distortion biased on a set of 8 1956 pre-calculated coefficients. You can get these coefficients by looking 1957 at the <a href="#verbose" >-verbose</a> output of a 1958 '<kbd>Prespective</kbd>' distortion, or by calculating them yourself. 1959 If the last two perspective scaling coefficients are zero, the 1960 remaining 6 represents a transposed 'Affine Matrix'. </td> 1961 1962 </tr> 1963 1964 <tr valign="top"> 1965 <td valign="top"><kbd>Arc</kbd></td> 1966 <td valign="top"> 1967 Arc the image (variation of polar mapping) over the angle given around 1968 a circle. <br/> 1969 <table width="90%" style = "margin-left: auto; margin-right: auto;"> 1970 <tr valign="top"><td>Argument</td> 1971 <td>Meaning</td></tr> 1972 <tr valign="top"><td><em>arc_angle</em></td> 1973 <td>The angle over which to arc the image side-to-side</td></tr> 1974 <tr valign="top"><td><em>rotate_angle</em></td> 1975 <td>Angle to rotate resulting image from vertical center</td></tr> 1976 <tr valign="top"><td><em>top_radius</em></td> 1977 <td>Set top edge of source image at this radius</td></tr> 1978 <tr valign="top"><td><em>bottom_radius</em> </td> 1979 <td>Set bottom edge to this radius (radial scaling)</td></tr> 1980 </table> 1981 1982 The resulting image is always resized to best fit the resulting image, 1983 (as if using <a href="#distort" >+distort</a>) while attempting to 1984 preserve scale and aspect ratio of the original image as much as 1985 possible with the arguments given by the user. All four arguments will 1986 be needed to change the overall aspect ratio of an 'Arc'ed image. <br/> 1987 1988 This a variation of a polar distortion designed to try to preserve the 1989 aspect ratio of the image rather than direct Cartesian to Polar 1990 conversion. </td> 1991 </tr> 1992 1993 <tr valign="top"> 1994 <td valign="top"><kbd>Polar</kbd></td> 1995 <td valign="top"> 1996 Like '<kbd>Arc</kbd>' but do a complete Cartesian to Polar mapping of 1997 the image. that is the height of the input image is mapped to the 1998 radius limits, while the width is wrapped around between the 1999 angle limits. <br/> 2000 2001 Arguments: <em>Rmax,Rmin CenterX,CenterY, start,end_angle</em> <br/> 2002 2003 All arguments are optional. With <em>Rmin</em> defaulting to zero, the 2004 center to the center of the image, and the angles going from -180 (top) 2005 to +180 (top). If <em>Rmax</em> is given the special value of 2006 '<code>0</code>', the the distance from the center to the nearest edge 2007 is used for the radius of the output image, which will ensure the whole 2008 image is visible (though scaled smaller). However a special value of 2009 '<code>-1</code>' will use the distance from the center to the furthest 2010 corner, This may 'clip' the corners from the input rectangular image, 2011 but will generate the exact reverse of a '<kbd>DePolar</kbd>' with 2012 the same arguments. <br/> 2013 2014 If the plus form of distort (<a href="#distort" >+distort</a>) is used 2015 output image center will default to <code>0,0</code> of the virtual 2016 canvas, and the image size adjusted to ensure the whole input image is 2017 made visible in the output image on the virtual canvas. </td> 2018 2019 </tr> 2020 2021 <tr valign="top"> 2022 <td valign="top"><kbd>DePolar</kbd></td> 2023 <td valign="top"> 2024 Uses the same arguments and meanings as a '<kbd>Polar</kbd>' distortion 2025 but generates the reverse Polar to Cartesian distortion. <br/> 2026 2027 The special <em>Rmax</em> setting of '<code>0</code>' may however clip 2028 the corners of the input image. However using the special 2029 <em>Rmax</em> setting of '<code>-1</code>' (maximum center to corner 2030 distance) will ensure the whole distorted image is preserved in the 2031 generated result, so that the same argument to '<kbd>Polar</kbd>' will 2032 reverse the distortion re-producing the original. 2033 2034 Note that as this distortion requires the area resampling of a circular 2035 arc, which can not be handled by the builtin EWA resampling function. 2036 As such the normal EWA filters are turned off. It is recommended some 2037 form of 'super-sampling' image processing technique be used to produce 2038 a high quality result. </td> 2039 2040 </tr> 2041 2042 <tr valign="top"> 2043 <td valign="top"><kbd>Barrel</kbd></td> 2044 <td valign="top"> 2045 Given the four coefficients (A,B,C,D) as defined by <a 2046 href="http://www.all-in-one.ee/~dersch/barrel/barrel.html" >Helmut 2047 Dersch</a>, perform a barrell or pin-cushion distortion appropriate to 2048 correct radial lens distortions. That is in photographs, make straight 2049 lines straight again. <br/> 2050 2051 Arguments: <em>A B C</em> [ <em>D</em> [ 2052 <em>X</em> , <em>Y</em> ] ] <br/> 2053 or <em>A<sub>x</sub> B<sub>x</sub> C<sub>x</sub> D<sub>x</sub> 2054 A<sub>y</sub> B<sub>y</sub> C<sub>y</sub> D<sub>y</sub></em> 2055 [ <em>X</em> , <em>Y</em> ] <br/> 2056 So that it forms the function <br/> 2057 Rsrc = r * ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> + 2058 <em>C</em>*r + <em>D</em> )<br/> 2059 2060 Where <em>X</em>,<em>Y</em> is the optional center of the distortion 2061 (defaulting to the center of the image). <br/> 2062 The second form is typically used to distort images, rather than 2063 correct lens distortions. <br/> 2064 </td> 2065 2066 </tr> 2067 2068 <tr valign="top"> 2069 <td valign="top"><kbd>BarrelInverse</kbd></td> 2070 <td valign="top"> 2071 This is very simular to '<kbd>Barrel</kbd>' with the same set of 2072 arguments, and argument handling. However it uses the inverse 2073 of the radial polynomial, 2074 so that it forms the function <br/> 2075 Rsrc = r / ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> + 2076 <em>C</em>*r + <em>D</em> )<br/> 2077 Note that this is not the reverse of the '<kbd>Barrel</kbd>' 2078 distortion, just a different barrel-like radial distortion method. 2079 2080 </td> 2081 </tr> 2082 2083 <tr valign="top"> 2084 <td valign="top"><kbd>Shepards</kbd></td> 2085 <td valign="top"> 2086 Distort the given list control points (any number) using an Inverse 2087 Squared Distance Interpolation Method (<a 2088 href="http://en.wikipedia.org/wiki/Shepard%27s_method" >Shepards 2089 Method</a>). The control points in effect do 'localized' displacement 2090 of the image around the given control point (preserving the look and 2091 the rotation of the area near the control points. For best results 2092 extra control points should be added to 'lock' the positions of the 2093 corners, edges and other unchanging parts of the image, to prevent 2094 their movement. <br/> 2095 2096 The distortion has been likened to 'taffy pulling' using nails, or 2097 pins' stuck in a block of 'jelly' which is then moved to the new 2098 position, distorting te surface of the jelly. <br/> 2099 2100 Internally it is equivelent to generating a displacement map (see <a 2101 href="#displace" >-displace</a>) for source image color look-up using 2102 the <a href="#sparse-color" >-sparse-color</a> method of the same name. 2103 2104 </td> 2105 </tr> 2106 2107</table> 2108 2109<p>To print a complete list of distortion methods, use <a href="#list">-list 2110distort</a>.</p> 2111 2112<p>Many of the above distortion methods such as '<kbd>Affine</kbd>', 2113'<kbd>Perspective</kbd>', and '<kbd>Shepards</kbd>' use a list control points 2114defining how these points in the given image should be distorted in the 2115destination image. Each set of four floating point values represent a source 2116image coordinate, followed immediately by the destination image coordinate. 2117This produces a list of values such as...</p> 2118<div style="text-align: center"><em> 2119 U<sub>1</sub>,V<sub>1</sub> X<sub>1</sub>,Y<sub>1</sub> 2120 U<sub>2</sub>,V<sub>2</sub> X<sub>2</sub>,Y<sub>2</sub> 2121 U<sub>3</sub>,V<sub>3</sub> X<sub>3</sub>,Y<sub>3</sub> 2122 ... 2123 U<sub>n</sub>,V<sub>n</sub> X<sub>n</sub>,Y<sub>n</sub> 2124</em></div> 2125<p>where <em>U,V</em> on the source image is mapped to <em>X,Y</em> on the 2126destination image. </p> 2127 2128<p>For example, to warp an image using '<kbd>perspective</kbd>' distortion, 2129needs a list of at least 4 sets of coordinates, or 16 numbers. Here is the 2130perspective distortion of the built-in "rose:" image. Note how spaces were 2131used to group the 4 sets of coordinate pairs, to make it easier to read and 2132understand.</p> 2133 2134<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'> 2135convert rose: -virtual-pixel black \<br/> 2136 -distort Perspective '0,0,0,0 0,45,0,45 69,0,60,10 69,45,60,35' \<br/> 2137 rose_3d_rotated.gif</span></p> 2138<p>If more that the required number of coordinate pairs are given for 2139a distortion, the distortion method is 'least squares' fitted to produce the 2140best result for all the coordinate pairs given. If less than the ideal number 2141of points are given, the distort will generally fall back to a simpler form of 2142distortion that can handles the smaller number of coordinates (usally a linear 2143'<kbd>Affine</kbd>' distortion). </p> 2144 2145<p>By using more coordinates you can make use of image registration tool to 2146find matching coordinate pairs in overlapping images, so as to improve the 2147'fit' of the distortion. Of course a bad coordinate pair can also make the 2148'fit' worse. Caution is always advised. </p> 2149 2150<p>Colors are acquired from the source image according to the <a 2151href="#interpolate" >-interpolate</a> color lookup setting, when the image is 2152magnified. However if the viewed image is minified (image becomes smaller), 2153a special area resampling function (added ImageMagick v6.3.5-9), is used to 2154produce a higher quality image. For example you can use 2155a '<kbd>perspective</kbd>' distortion to view a infinitely tiled 'plane' all 2156the way to the horizon. </p> 2157 2158<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'> 2159convert -size 90x90 pattern:checkerboard -normalize -virtual-pixel tile \<br/> 2160 -distort perspective '0,0,5,45 89,0,45,46 0,89,0,89 89,89,89,89' \<br/> 2161 checks_tiled.jpg</span></p> 2162<p>Note that a infinitely tiled perspective images involving the horizon can 2163be very slow to generate due to the use of the high quality 'area resampling' 2164function (added ImageMagick v6.3.5-9). You can turn off 'area resampling' 2165using a <a href="#filter" >-filter</a> setting of '<kbd>point</kbd>' 2166(recommended if you plan to use super-sampling instead). </p> 2167 2168<p>If an image generates <i>invalid pixels</i>, such as the 'sky' in the last 2169'<kbd>perspective</kbd>' distortion example, <a href="#distort" >-distort</a> 2170will use the current <a href="#mattecolor" >-mattecolor</a> setting for these 2171pixels. If you do not what these pixels to be visible, set the color to match 2172the rest of the ground. </p> 2173 2174<p>The output image size will by default be the same as the input image. This 2175means that if the part of the distorted image falls outside the viewed area of 2176the 'distorted space', those parts is clipped and lost. However if you use 2177the plus form of the operator (<a href="#distort" >+distort</a>) the operator 2178will attempt (if possible) to show the whole of the distorted image, while 2179retaining a correct 'virtual canvas' offset, for image layering. This offset 2180may need to be removed using <a href="#repage" >+repage</a>, to remove if it 2181is unwanted. </p> 2182 2183<p>You can alternatively specify a special "<kbd><a href="#set" >-set</a> 2184option:distort:viewport {geometry_string}</kbd>" setting which will specify 2185the size and the offset of the generated 'viewport' image of the distorted 2186image space.</p> 2187 2188<p>Adding a "<kbd><a href="#set" >-set</a> option:distort:scale 2189{scale_factor}</kbd>" will scale the output image (viewport or otherwise) by 2190that factor without changing the viewed contents of the distorted image. This 2191can be used either for 'super-sampling' the image for a higher quality result, 2192or for panning and zooming around the image (with appropriate viewport 2193changes, or post-distort cropping and resizing). </p> 2194 2195<p>Setting <a href="#verbose" >-verbose</a> setting, will cause <a 2196href="#distort" >-distort</a> to attempt to output the internal coefficients, 2197and the <a href="#fx" >-fx</a> equivalent to the distortion, for expert study, 2198and debugging purposes. This many not be available for all distorts. </p> 2199 2200<p>Affine rotations and shears (such as '<kbd>SRT</kbd>' distortion), tend to 2201produce a cleaner result that the equivalent <a href="#rotate" >-rotate</a> 2202and/or <a href="#shear" >-shear</a> operation, with more control of due to the 2203above settings. It is algorithmically slower however, though that may not be 2204the case in ImageMagick's implementation. </p> 2205 2206 2207<div style="margin: auto;"> 2208 <h4><a name="dither" id="dither"></a>-dither <em class="arg">method</em></h4> 2209</div> 2210 2211<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> 2212 2213<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> 2214 2215<p>Dithering is turned on by default, to turn it off use the plus form of the 2216setting, <a href="#dither">+dither</a>. This will also also render PostScript 2217without text or graphic aliasing. Disabling dithering often (but not always) 2218leads to faster process, a smaller number of colors, but more cartoon like 2219image coloring. Generally resulting in 'color banding' effects in areas with 2220color gradients. </p> 2221 2222<p>The color reduction operators <a href="#colors">-colors</a>, <a 2223href="#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> 2224 2225<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> 2226 2227 2228<div style="margin: auto;"> 2229 <h4><a name="draw" id="draw"></a>-draw <em class="arg">string</em></h4> 2230</div> 2231 2232<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> 2233 2234<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> 2235 2236<p>The shape primitives:</p> 2237 2238<pre class="text"> 2239 point x,y 2240 line x0,y0 x1,y1 2241 rectangle x0,y0 x1,y1 2242 roundRectangle x0,y0 x1,y1 wc,hc 2243 arc x0,y0 x1,y1 a0,a1 2244 ellipse x0,y0 rx,ry a0,a1 2245 circle x0,y0 x1,y1 2246 polyline x0,y0 ... xn,yn 2247 polygon x0,y0 ... xn,yn 2248 bezier x0,y0 ... xn,yn 2249 path path specification 2250 image operator x0,y0 w,h filename 2251</pre> 2252 2253<p>The text primitive:</p> 2254 2255<pre class="text"> 2256 text x0,y0 string 2257</pre> 2258<p>The text gravity primitive:</p> 2259 2260<pre class="text"> 2261 gravity NorthWest, North, NorthEast, West, Center, 2262 East, SouthWest, South, or SouthEast 2263</pre> 2264 2265<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> 2266 2267<p>The transformation primitives:</p> 2268 2269<pre class="text"> 2270 rotate degrees 2271 translate dx,dy 2272 scale sx,sy 2273 skewX degrees 2274 skewY degrees 2275</pre> 2276 2277<p>The pixel operation primitives:</p> 2278 2279<pre class="text"> 2280 color x0,y0 method 2281 matte x0,y0 method 2282</pre> 2283 2284<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> 2285 2286<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> 2287 2288<p>A <kbd>line</kbd> primitive requires a start point and end point.</p> 2289 2290<p>A <kbd>rectangle</kbd> primitive is specified by the pair of points at the upper left and lower right corners.</p> 2291 2292<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> 2293 2294<p>The <kbd>circle</kbd> primitive makes a disk (filled) or circle (unfilled). Give the center and any point on the perimeter (boundary).</p> 2295 2296<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> 2297 2298<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> 2299 2300<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>. 2301</p> 2302 2303<p>A <em>coordinate</em> is a pair of integers separated by a space or optional comma. </p> 2304 2305<p>As an example, to define a circle centered at 100,100 that extends to 150,150 use:</p> 2306 2307<p class="crtsnip"> 2308 -draw 'circle 100,100 150,150' 2309</p> 2310 2311<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 2312draw 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> 2313 2314<p class="crtsnip"> 2315 -draw 'bezier 20,50 45,100 45,0 70,50' 2316</p> 2317<p class="crtsnip"> 2318 -draw 'bezier 70,50 95,100 95,0 120,50' 2319</p> 2320 2321 2322<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> 2323 2324<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> 2325 2326<p class="crtsnip"> 2327 -draw 'image SrcOver 100,100 225,225 image.jpg' 2328</p> 2329 2330<p>You can use 0,0 for the image size, which means to use the actual 2331dimensions found in the image header. Otherwise, it is scaled to the given 2332dimensions. See <a href="/www/compose.html">Alpha Compositing</a> for 2333a detailed discussion of alpha composition methods that are available. </p> 2334 2335<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> 2336 2337<p>For example, the following annotates the image with <kbd>Works like magick!</kbd> for an image titled <kbd>bird.miff</kbd>. </p> 2338 2339<p class="crtsnip"> 2340 -draw 'text 100,100 "Works like magick!"' 2341</p> 2342 2343<p>See the <a href="#annotate">-annotate</a> option for another convenient way to annotate an image with text.</p> 2344 2345<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> 2346 2347<p>The <kbd>translate</kbd> primitive translates subsequent shape and text primitives.</p> 2348 2349<p>The <kbd>scale</kbd> primitive scales them.</p> 2350 2351<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> 2352 2353<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 2354matrix.</p> 2355 2356<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> 2357 2358<pre class="text"> 2359 point 2360 replace 2361 floodfill 2362 filltoborder 2363 reset 2364</pre> 2365 2366<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> 2367 2368<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> 2369 2370<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> 2371 2372<p>Strings that begin with a number must be quoted (e.g. use '1.png' rather than 1.png).</p> 2373 2374<p>Drawing primitives conform to the <a href="/www/magick-vector-graphics.html">Magick Vector Graphics</a> format.</p> 2375 2376 2377<div style="margin: auto;"> 2378 <h4><a name="edge" id="edge"></a>-edge <em class="arg">radius</em></h4> 2379</div> 2380 2381<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> 2382 2383<div style="margin: auto;"> 2384 <h4><a name="emboss" id="emboss"></a>-emboss <em class="arg">radius</em></h4> 2385</div> 2386 2387<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> 2388 2389<div style="margin: auto;"> 2390 <h4><a name="encipher" id="encipher"></a>-encipher <em class="arg">filename</em></h4> 2391</div> 2392 2393<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> 2394 2395<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p> 2396 2397<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p> 2398 2399 2400 2401<div style="margin: auto;"> 2402 <h4><a name="encoding" id="encoding"></a>-encoding <em class="arg">type</em></h4> 2403</div> 2404 2405<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> 2406 2407<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> 2408 2409<div style="margin: auto;"> 2410 <h4><a name="endian" id="endian"></a>-endian <em class="arg">type</em></h4> 2411</div> 2412 2413<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> 2414 2415<p>To print a complete list of endian types, use the <a href="#list">-list endian</a> option.</p> 2416 2417<p>Use <a href="#endian">+endian</a> to revert to unspecified endianness.</p> 2418 2419 2420<div style="margin: auto;"> 2421 <h4><a name="enhance" id="enhance"></a>-enhance</h4> 2422</div> 2423 2424<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> 2425 2426 2427<div style="margin: auto;"> 2428 <h4><a name="equalize" id="equalize"></a>-equalize</h4> 2429</div> 2430 2431<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> 2432 2433<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> 2434 2435<p>For example using HSL, we have: ... <kbd>-colorspace HSL -channel lightness -equalize -colorspace RGB</kbd> ...</p> 2436 2437<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> 2438 2439<div style="margin: auto;"> 2440 <h4><a name="evaluate" id="evaluate"></a>-evaluate <em class="arg">operator value</em></h4> 2441</div> 2442 2443<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> 2444 2445<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> 2446 2447<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> 2448 2449<table class="doc"> 2450 <col width="25%" /> 2451 <col width="75%" /> 2452 <thead> 2453 <tr> 2454 <th><em class="arg">operator</em></th> 2455 <th>Summary (see further below for details)</th> 2456 </tr> 2457 </thead> 2458 <tbody> 2459 2460 <tr><td>Abs </td> <td>Add <em class="arg">value</em> to pixels and return absolute value. </td></tr> 2461 <tr><td>Add </td> <td>Add <em class="arg">value</em> to pixels. </td></tr> 2462 <tr><td>AddModulus </td> <td>Add <em class="arg">value</em> to pixels modulo <em class="QR">QuantumRange</em>.</td></tr> 2463 <tr><td>And </td> <td>Binary AND of pixels with <em class="arg">value</em>.</td></tr> 2464 <tr><td>Cos, Cosine </td> <td>Apply cosine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr> 2465 <tr><td>Divide </td> <td>Divide pixels by <em class="arg">value</em>.</td></tr> 2466 <tr><td>Exp </td> <td>base-e exponential function</td></tr> 2467 <tr><td>Exponential </td> <td>base-e exponential function</td></tr> 2468 <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> 2469 <tr><td>Log </td> <td>Apply scaled logarithm to normalized pixels.</td></tr> 2470 <tr><td>Max </td> <td>Clip pixels at lower bound <em class="arg">value</em>.</td></tr> 2471 <tr><td>Mean </td> <td>Add the <em class="arg">value</em> and divide by 2.</td></tr> 2472 <tr><td>Min </td> <td>Clip pixels at upper bound <em class="arg">value</em>.</td></tr> 2473 <tr><td>Multiply </td> <td>Multiply pixels by <em class="arg">value</em>.</td></tr> 2474 <tr><td>Or </td> <td>Binary OR of pixels with <em class="arg">value</em>.</td></tr> 2475 <tr><td>Pow </td> <td>Raise normalized pixels to the power <em class="arg">value</em>.</td></tr> 2476 <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> 2477 <tr><td>Set </td> <td>Set pixel equal to <em class="arg">value</em>.</td></tr> 2478 <tr><td>Sin, Sine </td> <td>Apply sine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr> 2479 <tr><td>Subtract </td> <td>Subtract <em class="arg">value</em> from pixels.</td></tr> 2480 <tr><td>Xor </td> <td>Binary XOR of pixels with <em class="arg">value.</em></td></tr> 2481 2482 <tr><td> </td></tr> 2483 2484 <tr><td>Gaussian-noise</td></tr> 2485 <tr><td>Impulse-noise</td></tr> 2486 <tr><td>Laplacian-noise</td></tr> 2487 <tr><td>Multiplicative-noise</td> <td>(These are equivalent to the corresponding <a href="#noise" >-noise</a> operators.)</td></tr> 2488 <tr><td>PoissonNoise</td></tr> 2489 <tr><td>Uniform-noise</td></tr> 2490 2491 <tr><td> </td></tr> 2492 2493 <tr><td>Threshold </td> <td>Threshold pixels larger than <em class="arg">value</em>.</td></tr> 2494 <tr><td>ThresholdBlack </td> <td>Threshold pixels to zero values equal to or below <em class="arg">value</em>.</td></tr> 2495 <tr><td>ThresholdWhite </td> <td>Threshold pixels to maximum values above <em class="arg">value</em>. </td></tr> 2496 </tbody> 2497 </table> 2498 2499<p>The specified functions are applied only to each previously set <a 2500href="#channel" >-channel</a> in the image. If necessary, the results of the 2501calculations are truncated (clipped) to fit in the interval [0, <em 2502class="QR">QuantumRange</em>]. The transparency channel of the image is 2503represented as a 'alpha' values (0 = fully transparent), so, for example, a 2504<kbd>Divide</kbd> by 2 of the alpha channel will make the image 2505semi-transparent. Append the percent symbol '<kbd>%</kbd>' to specify a value 2506as a percentage of the <em class="QR">QuantumRange</em>.</p> 2507 2508<p>To print a complete list of <a href="#evaluate">-evaluate</a> operators, use 2509<a href="#list">-list evaluate</a>.</p> 2510 2511<p>The results of the <kbd>Add</kbd>, <kbd>Subtract</kbd> and 2512<kbd>Multiply</kbd> methods can also be achieved using either the <a 2513href="#level" >-level</a> or the <a href="#level" >+level</a> operator, with 2514appropriate argument, to linearly modify the overall range of color values. 2515Please note, however, that <a href="#level" >-level</a> treats transparency as 2516'matte' values (0 = opaque), while <a href="#level" >-evaluate</a> works with 2517'alpha' values.</p> 2518 2519<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> 2520 2521<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> 2522 2523 <div style="text-align:center;"> 2524 exp(<em class="arg">value</em> × <b><em>u</em></b>) 2525 </div> 2526 2527<p> If the input image is squared, for example, using <a 2528href="#-function" >-function polynomial "2 0 0"</a>, then a decaying Gaussian function will be the result.</p> 2529 2530<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> 2531 2532 <div style="text-align:center;"> 2533 log(<em class="arg">value</em> × <b><em>u</em></b> + 1) / log(<em class="arg">value</em> + 1) 2534 </div> 2535 2536<p><kbd>Pow</kbd> has been added as of ImageMagick 6.4.1-9, and works on 2537normalized pixel values. Note that <kbd>Pow</kbd> is related to the <a 2538href="#gamma" >-gamma</a> operator. For example, <b>-gamma 2</b> is equivalent 2539to <b>-evaluate pow 0.5</b>, i.e., a 'square root' function. The value used 2540with <a href="#gamma" >-gamma</a> is simply the reciprocal of the value used 2541with <kbd>Pow</kbd>.</p> 2542 2543<p><kbd>Cosine</kbd> and <kbd>Sine</kbd> was added as of IM v6.4.8-8 and 2544converts the image values into a value according to a (co)sine wave function. 2545The synonyms <kbd>Cos</kbd> and <kbd>Sin</kbd> may also be used. The output 2546is biased 50% and normalized by 50% so as to fit in the respective color value 2547range. The <em class="arg">value</em> scaling of the <em>period</em> of the 2548function (its frequency), and thus determines the number of 'waves' that will 2549be generated over the input color range. For example, if the <em 2550class="arg">value</em> is 1, the effective period is simply the <em 2551class="QR">QuantumRange</em>; but if the <em class="arg">value</em> is 2, 2552then the effective period is the <em>half</em> the <em 2553class="QR">QuantumRange</em>. 2554 2555 <div style="text-align:center;"> 2556 0.5 + 0.5 × cos(2 π <b><em>u</em></b> × <em class="arg">value</em>). 2557 </div> 2558 2559See also the <a href="#function" >-function</a> operator, which is a 2560multi-value version of evaluate. </P> 2561 2562<div style="margin: auto;"> 2563 <h4><a name="evaluate-sequence" id="evaluate-sequence"></a>-evaluate-sequence <em class="arg">operator</em></h4> 2564</div> 2565 2566<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> 2567 2568<div style="margin: auto;"> 2569 <h4><a name="extent" id="extent"></a>-extent <em class="arg">geometry</em></h4> 2570</div> 2571 2572<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> 2573 2574<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> 2575<p>This command reduces or expands a JPEG image to fit on an 800x600 2576display. If the aspect ratio of the input image isn't exactly 4:3, then the 2577image is centered on an 800x600 black canvas: </p> 2578 2579<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> 2580 2581 2582<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> 2583 2584<div style="margin: auto;"> 2585 <h4><a name="extract" id="extract"></a>-extract <em class="arg">geometry</em></h4> 2586</div> 2587 2588<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> 2589 2590<p>This option is most useful for extracting a subregion of a very large raw image. Note that these two commands are equivalent:</p> 2591 2592<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> 2593 2594<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> 2595<p>the image is <em>resized</em> to the specified dimensions instead, 2596equivalent to:</p> 2597 2598<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 -resize 640x480 image.rgb image.png</span></p> 2599<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> 2600 2601<div style="margin: auto;"> 2602 <h4><a name="family" id="family"></a>-family <em class="arg">fontFamily</em></h4> 2603</div> 2604 2605<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> 2606 2607<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). 2608</p> 2609 2610<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>. 2611</p> 2612 2613<div style="margin: auto;"> 2614 <h4><a name="features" id="features"></a>-features <em class="arg">distance</em></h4> 2615</div> 2616 2617<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> 2618 2619<div style="margin: auto;"> 2620 <h4><a name="fft" id="fft"></a>-fft</h4> 2621</div> 2622 2623<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> 2624 2625<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" target="_blank">Fourier Transform</a>, <a href="http://en.wikipedia.org/wiki/DFT" target="_blank">Discrete Fourier Transform</a> and <a href="http://en.wikipedia.org/wiki/FFT" target="_blank">Fast Fourier Transform</a>.</p> 2626 2627<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" target="_blank">Complex Numbers</a>.<p> 2628 2629<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> 2630 2631<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -fft fft_image.miff</span></p> 2632<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> 2633 2634<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -fft fft_image.png</span></p> 2635<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> 2636 2637<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> 2638 2639<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> 2640 2641<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert fft_image.miff[0] -contrast-stretch 0 \ <br /> 2642 -evaluate log 1000 fft_image_spectrum.png</span></p> 2643<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> 2644 2645<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#fft">-fft</a>. 2646 2647<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> 2648 2649<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> 2650 2651<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.</a> 2652 2653<p>See the discussion on HDRI implementations of ImageMagick on the page 2654<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. 2655</p> 2656 2657 2658<div style="margin: auto;"> 2659 <h4><a name="fill" id="fill"></a>-fill <em class="arg">color</em></h4> 2660</div> 2661 2662<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> 2663 2664<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> 2665 2666<p>Enclose the color specification in quotation marks to prevent the "#" or the parentheses from being interpreted by your shell.</p> 2667 2668<p>For example,</p> 2669 2670<p class="crtsnip"> 2671 -fill blue 2672</p> 2673<p class="crtsnip"> 2674 -fill "#ddddff" 2675</p> 2676<p class="crtsnip"> 2677 -fill "rgb(255,255,255)" 2678</p> 2679 2680<p>See <a href="#draw">-draw</a> for further details.</p> 2681 2682<p>To print a complete list of color names, use the <a href="#list">-list color</a> option.</p> 2683 2684<div style="margin: auto;"> 2685 <h4><a name="filter" id="filter"></a>-filter <em class="arg">type</em></h4> 2686</div> 2687 2688<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 2689distorting an image.</td><td style='text-align:right;'></td></tr></table> 2690 2691<p>Use this option to affect the resizing operation of an image during 2692operations such as <a href="#resize">-resize</a> and <a href="#distort" 2693>-distort</a>. For example you can use a simple resize filter such as:</p> 2694 2695<pre class="text"> 2696 Point Hermite Cubic 2697 Box Gaussian Catrom 2698 Triangle Quadratic Mitchell 2699</pre> 2700 2701<p>The <kbd>Bessel</kbd> and <kbd>Sinc</kbd> filter is also provided (as well 2702as a faster <kbd>SincFast</kbd> equivalent form). However these filters are 2703generally useless on their own as they are infinite filters that are being 2704clipped to the filters support size. Their direct use is not recommended 2705except via expert settings (see below). </p> 2706 2707Instead these special filter functions are typically windowed by a windowing 2708function that the <a href="#filter" >-filter</a> setting defines. That is 2709using these functions will define a 'Windowed' filter, appropriate to the 2710operator involved. Windowed filters include: </p> 2711 2712<pre class="text"> 2713 Lanczos Hamming Parzen 2714 Blackman Kaiser Welsh 2715 Hanning Bartlett Bohman 2716</pre> 2717 2718<p>Also one special self-windowing filter is also provided 2719<kbd>Lagrange</kbd>, which will automagically re-adjust its function depending 2720on the current 'support' or 'lobes' expert settings (see below).</p> 2721 2722<p>If you do not select a filter with this option, the filter defaults to 2723<kbd>Mitchell</kbd> for a colormapped image, a image with a matte channel, or 2724if the image is enlarged. Otherwise the filter default to 2725<kbd>Lanczos</kbd>.</p> 2726 2727<p>To print a complete list of resize filters, use the <a href="#list">-list 2728filter</a> option.</p> 2729 2730<p>You can modify how the filter behaves as it scales your image through the 2731use of these expert settings (see also <a href="#define" >-define</a> and <a 2732href="#set" >-set</a>):-</p> 2733 2734<dl class="doc"> 2735<dt>-define filter:blur=<em>factor</em></dt> 2736<dd>Scale the X axis of the filter (and its window). Use > 1.0 for 2737 blurry or < 1.0 for sharp. This should only be used with Gaussian and 2738 Gaussian-like filters simple filters, or you may not get the expected 2739 results. </dd> 2740 2741<dt>-define filter:support=<em>radius</em></dt> 2742<dd>Set the filter support radius. Defines how large the filter should be and 2743 thus directly defines how slow the filtered resampling process is. All 2744 filters have a default 'prefered' support size. Some filters like 2745 <kbd>Lagrange</kbd> and windowed filters adjust themselves depending on 2746 this value. With simple filters this value either does nothing (but slow 2747 the resampling), or will clip the filter function in a detrimental way. 2748 </dd> 2749 2750<dt>-define filter:lobes=<em>count</em></dt> 2751<dd>Set the number of lobes to use for the Sinc/Bessel filter. This an 2752 alternative way of specifying the 'support' range of the filter, that is 2753 designed to be more suited to windowed filters, especially when used for 2754 image distorts.</dd> 2755 2756<dt>-define filter:b=<em>b-spline_factor</em></dt> 2757<dt>-define filter:c=<em>keys_alpha_factor</em></dt> 2758<dd>Redefine the values used for cubic filters such as <kbd>Cubic</kbd>, 2759 <kbd>Catrom</kbd>, <kbd>Mitchel</kbd>, and <kbd>Hermite</kbd>, as well as 2760 the <kbd>Parzen</kbd> Sinc windowing function. If only one of the values 2761 are defined, the other is set so as to generate a 'Keys' type cubic 2762 filter. Values meaning was defined by a research paper by 2763 Mitchell-Netravali. 2764 2765<dt>-define filter:filter=<em>filter_function</em></dt> 2766<dd>Use this function directly as the scaling filter. This will allow 2767 you to directly use a windowing filter such as <kbd>Blackman</kbd>, 2768 rather than as its normal usage as a windowing function for 'Sinc' or 2769 'Bessel' functions. If defined, no windowing function is used, unless the 2770 following expert setting is also defined.</dd> 2771 2772<dt>-define filter:window=<em>filter_function</em></dt> 2773<dd>The IIR (infinite impulse response) filters <kbd>Bessel</kbd> and 2774 <kbd>Sinc</kbd> are windowed (brought down to zero over the defined 2775 support range) with the given filter. This allows you to specify a filter 2776 function that is not normally used as a windowing function, such as 2777 <kbd>Box</kbd>, (which effectively turns off the windowing function), 2778 to window a <kbd>Sinc</kbd>, or the function the previous setting defined. 2779 </dd> 2780 2781<dt>-define filter:verbose=<em>1</em></dt> 2782<dd>This causes IM to print information on the final internal filter 2783 selection to standard output. This includes a commented header on the 2784 filter settings being used, and data allowing the filter weights to be 2785 easily graphed. </dd> 2786 2787<dd>Note however that some filters are internally defined in terms of other 2788 filters. The <kbd>Lanczos</kbd> filter for example is defined in terms of 2789 a <kbd>SincFast</kbd> windowed <kbd>SincFast</kbd> filter, while 2790 <kbd>Mitchell</kbd> is defined as a <kbd>Cubic</kbd> filter with specific 2791 'B' and 'C' settings. </dd> 2792 2793</dl> 2794 2795<p>For example, to get a 8 lobe Bessel windowed Bessel filter:</p> 2796 2797<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -filter bessel \ <br/> 2798 -set filter:window=bessel -set filter:lobes=8 \ <br/> 2799 -resize 150% image.jpg</span></p> 2800<p>Or a raw un-windowed Sinc filter with 4 lobes:</p> 2801 2802<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -set filter:filter=sinc -set filter:lobes=4 \ <br/> 2803 -resize 150% image.jpg</span></p> 2804<p>Note that the use of expert options (except for 'blur' with simple resize 2805filters, and 'verbose' for viewing the internal filter selection), are 2806provided for image processing experts who have studied and understood how 2807resize filters work. Without this knowledge, and an understanding of the 2808definition of the actual filters involved, using expert settings are more 2809likely to be detrimental to your image resizing.</p> 2810 2811 2812<div style="margin: auto;"> 2813 <h4><a name="flatten" id="flatten"></a>-flatten</h4> 2814</div> 2815 2816<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> 2817 2818 2819<div style="margin: auto;"> 2820 <h4><a name="flip" id="flip"></a>-flip</h4> 2821</div> 2822 2823<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> 2824 2825<p>reflect the scanlines in the vertical direction.</p> 2826 2827<div style="margin: auto;"> 2828 <h4><a name="floodfill" 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> 2829</div> 2830 2831<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> 2832 2833<div style="margin: auto;"> 2834 <h4><a name="flop" id="flop"></a>-flop</h4> 2835</div> 2836 2837<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> 2838 2839<p>reflect the scanlines in the horizontal direction.</p> 2840 2841 2842<div style="margin: auto;"> 2843 <h4><a name="font" id="font"></a>-font <em class="arg">name</em></h4> 2844</div> 2845 2846<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> 2847 2848<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> 2849 2850<p>In addition to the fonts specified by the above pre-defined list, you can 2851also specify a font from a specific source. For example <kbd>Arial.ttf</kbd> 2852is a TrueType font file, <kbd>ps:helvetica</kbd> is PostScript font, and 2853<kbd>x:fixed</kbd> is X11 font.</p> 2854 2855<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> 2856 2857 2858<div style="margin: auto;"> 2859 <h4><a name="foreground" id="foreground"></a>-foreground <em class="arg">color</em></h4> 2860</div> 2861 2862<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> 2863 2864<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 2865 2866<p>The default foreground color is black.</p> 2867 2868<div style="margin: auto;"> 2869 <h4><a name="format" id="format"></a>-format <em class="arg">type</em></h4> 2870</div> 2871 2872<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> 2873 2874<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> 2875 2876<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> 2877 2878<div style="margin: auto;"> 2879 <h4><a name="format_identify_" id="format_identify_"></a>-format <em class="arg">string</em></h4> 2880</div> 2881 2882<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> 2883 2884<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> 2885 2886<div style="margin: auto;"> 2887 <h4><a name="frame" id="frame"></a>-frame <em class="arg">geometry</em></h4> 2888</div> 2889 2890<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> 2891 2892<p>The color of the border is specified with the <a href="#mattecolor" 2893>-mattecolor</a> command line option. </p> 2894 2895<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 2896class="arg">geometry</em> argument indicates the amount of extra width and 2897height that is added to the dimensions of the image. If no offsets are given 2898in the <em class="arg">geometry</em> argument, then the border added is 2899a solid color. Offsets <em>x</em> and <em>y</em>, if present, specify that 2900the width and height of the border is partitioned to form an outer bevel of 2901thickness <em>x</em> pixels and an inner bevel of thickness 2902<em>y</em> pixels. Negative offsets make no sense as frame arguments. 2903</p> 2904 2905<p>The <a href="#frame">-frame</a> option is affected by the current <a 2906href="#compose">-compose</a> setting and assumes that this is using the default 2907'<kbd>Over</kbd>' composition method. It generates a image of the appropriate 2908size with the current <a href="#bordercolor">-bordercolor</a> setting, and then 2909draws the frame of four distinct colors close to the current <a 2910href="#mattecolor">-mattecolor</a>. The original image is then overlaid onto 2911center of this image. This means that with the default compose method of 2912'<kbd>Over</kbd>' any transparent parts may be replaced by the current <a 2913href="#bordercolor">-bordercolor</a> setting.</p> 2914 2915<p>The image composition is not 2916affected by the <a href="#gravity">-gravity</a> option.</p> 2917 2918 2919<div style="margin: auto;"> 2920 <h4><a name="frame_import_" id="frame_import_"></a>-frame</h4> 2921</div> 2922 2923<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> 2924 2925<div style="margin: auto;"> 2926 <h4><a name="function" id="function"></a>-function <em class="arg">function</em> <em class="arg">parameters</em></h4> 2927</div> 2928 2929<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> 2930 2931<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> 2932 2933<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> 2934 2935<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> 2936 2937<pre class="text"> 2938 Polynomial 2939 Sinusoid 2940 Arcsin 2941 Arctan 2942</pre> 2943 2944<p>To print a complete list of <a href="#function">-function</a> operators, use <a href="#list">-list function</a>. Descriptions follow.</p> 2945 2946<dl class="doc"> 2947<dt><kbd>Polynomial</kbd></dt> 2948<dd> 2949<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> 2950 2951<div style="text-align: center"> 2952 -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> 2953</div> 2954 2955<p>will invoke a polynomial function given by</p> 2956 2957<div style="text-align: center"> 2958 <em>a</em><sub><em>n</em></sub> <b><em>u</em></b><sup><em>n</em></sup> + 2959 <em>a</em><sub><em>n</em>-1</sub> <b><em>u</em></b><sup><em>n</em>-1</sup> + 2960 ··· <em>a</em><sub>1</sub> <b><em>u</em></b> + <em>a</em><sub>0</sub>, 2961</div> 2962 2963<p>where <b><em>u</em></b> is pixel's original normalized channel value.</p> 2964 2965<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> 2966 2967<table class="doc"> 2968 <col width="35%" /> 2969 <col width="35%" /> 2970 <col width="30%" /> 2971 <tr> 2972 <td>-evaluate Set <em class="arg">value</em> </td> 2973 <td>-function Polynomial <em class="arg">value</em></td> 2974 <td>(Constant functions; set <em class="arg">value</em>×100% gray when channels are RGB.)</td> 2975 </tr> 2976 <tr> 2977 <td>-evaluate Add <em class="arg">value</em> </td> 2978 <td>-function Polynomial 1,<em class="arg">value</em></td> 2979 </tr> 2980 <tr> 2981 <td>-evaluate Subtract <em class="arg">value</em> </td> 2982 <td>-function Polynomial 1,−<em class="arg">value</em></td> 2983 </tr> 2984 <tr> 2985 <td>-evaluate Multiply <em class="arg">value</em> </td> 2986 <td>-function Polynomial <em class="arg">value</em>,0</td> 2987 </tr> 2988 <tr> 2989 <td>+level black% x white%</td> 2990 <td>-function Polynomial A,B</td> 2991 <td>(Reduce contrast. Here, A=(white-black)/100 and B=black/100.)</td> 2992 </tr> 2993</table> 2994 2995<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> 2996</dd> 2997 2998<dt><kbd>Sinusoid</kbd></dt> 2999<dd> 3000<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> 3001 3002<div style="text-align: center"> 3003 -function <kbd>Sinusoid</kbd> <em class="arg">freq</em>,[<em class="arg">phase</em>,[<em class="arg">amp</em>,[<em class="arg">bias</em>]]] 3004</div> 3005 3006<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> 3007 3008<div style="text-align: center"> 3009<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> 3010</div> 3011 3012<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> 3013 3014<p class="crtsnip"> 3015 -function Sinusoid 3,-90,.2,.7 3016</p> 3017 3018<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> 3019 3020<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> 3021 3022<table class="doc"> 3023 <tr> 3024 <td>-evaluate Sin <em class="arg">freq</em> </td> 3025 <td>-function Sinusoid <em class="arg">freq</em>,0 </td> 3026 </tr> 3027 <tr> 3028 <td>-evaluate Cos <em class="arg">freq</em> </td> 3029 <td>-function Sinusoid <em class="arg">freq</em>,90 </td> 3030 </tr> 3031</table> 3032</dd> 3033 3034<dt><kbd>ArcSin</kbd></dt> 3035<dd> 3036<p>The <kbd>ArcSin</kbd> function generates the inverse curve of a Sinusoid, 3037and can be used to generate cylindrical distortion and displacement maps. 3038The curve can be adjusted relative to both the input values and output range 3039of values. 3040 3041<div style="text-align: center"> 3042 -function <kbd>ArcSin</kbd> <em class="arg">width</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]] 3043</div> 3044 3045<p>with all values given in terms of noramlize color values (0.0 for black, 30461.0 for white). Defaulting to values covering the full range from 0.0 to 1.0 3047for bout input (<em class="arg">width</em>), and output (<em 3048class="arg">width</em>) values. '<code>1.0,0.5,1.0,0.5</code>' </p> 3049 3050<div style="text-align: center"> 3051<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> 3052</div> 3053 3054</dd> 3055 3056<dt><kbd>ArcTan</kbd></dt> 3057<dd> 3058<p>The <kbd>ArcTan</kbd> function generates a curve that smooth crosses from 3059limit values at infinities, though a center using the given slope value. 3060All these values can be adjusted via the arguments. 3061 3062<div style="text-align: center"> 3063 -function <kbd>ArcTan</kbd> <em class="arg">slope</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]] 3064</div> 3065 3066<p>Defaulting to '<code>1.0,0.5,1.0,0.5</code>'. 3067</p> 3068 3069<div style="text-align: center"> 3070<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> 3071</div> 3072 3073</dd> 3074 3075</dl> 3076 3077 3078<div style="margin: auto;"> 3079 <h4><a name="fuzz" id="fuzz"></a>-fuzz <em class="arg">distance</em>{<em class="arg">%</em>}</h4> 3080</div> 3081 3082<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> 3083 3084<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> 3085 3086<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> 3087 3088 3089<div style="margin: auto;"> 3090 <h4><a name="fx" id="fx"></a>-fx <em class="arg">expression</em></h4> 3091</div> 3092 3093<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> 3094 3095<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> 3096 3097<p>See <a href="/www/fx.html">FX, The Special Effects Image Operator</a> for a detailed discussion of this option.</p> 3098 3099 3100<div style="margin: auto;"> 3101 <h4><a name="gamma" id="gamma"></a>-gamma <em class="arg">value</em></h4> 3102</div> 3103 3104<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> 3105 3106<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> 3107 3108<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> 3109 3110<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> 3111 3112<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> 3113 3114<p>Note that gamma adjustments are also available via the <a href="#level">-level</a> operator.</p> 3115 3116<div style="margin: auto;"> 3117 <h4><a name="gaussian-blur" 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> 3118</div> 3119 3120<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> 3121 3122<p>Convolve the image with a Gaussian or normal distribution using the given 3123<em class="arg" >Sigma</em> value. The formula is:</p> 3124 3125<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="/images/gaussian-blur.png"/> 3126</div> 3127 3128<p>The <em class="arg" >Sigma</em> value is the important argument, and 3129determines the actual amount of bluring that will take place. </p> 3130 3131<p>The <em class="arg" >Radius</em> is only used to determine the size of the 3132array which will hold the calculated gaussian distribution. It should be an 3133integer. If not given, or set to zero, IM will calculate the largest possible 3134radius that will provide meaningful results for the Gaussian distribution. 3135</p> 3136 3137<p>The larger the <em class="arg" >Radius</em> the radius the slower the 3138operation is. However too small a <em class="arg" >Radius</em>, and sever 3139aliasing effects may result. As a guideline, <em class="arg" >Radius</em> 3140should be at least twice the <em class="arg" >Sigma</em> value, though three 3141times will produce a more accurite result. </p> 3142 3143<p>This differs from the faster <a href="#blur">-blur</a> operator in that a 3144full 2-dimensional convolution is used to generate the weighted average of the 3145neighboring pixels. </p> 3146 3147<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 3148pixels which are outside the image proper are blurred into the final result. 3149</p> 3150 3151 3152<div style="margin: auto;"> 3153 <h4><a name="geometry" id="geometry"></a>-geometry <em class="arg">geometry</em></h4> 3154</div> 3155 3156<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> 3157 3158<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> 3159 3160<div style="margin: auto;"> 3161 <h4><a name="gravity" id="gravity"></a>-gravity <em class="arg">type</em></h4> 3162</div> 3163 3164<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> 3165 3166<p>Choices include: <kbd>NorthWest</kbd>, <kbd>North</kbd>, <kbd>NorthEast</kbd>, 3167<kbd>West</kbd>, <kbd>Center</kbd>, <kbd>East</kbd>, <kbd>SouthWest</kbd>, 3168<kbd>South</kbd>, <kbd>SouthEast</kbd>. Use <a href="#list">-list gravity</a> to get a complete 3169list of <a href="#gravity">-gravity</a> settings available in your ImageMagick 3170installation.</p> 3171 3172<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> 3173 3174<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> 3175 3176<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> 3177 3178<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> 3179<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> 3180 3181<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> 3182 3183 3184<div style="margin: auto;"> 3185 <h4><a name="green-primary" id="green-primary"></a>-green-primary <em class="arg">x,y</em></h4> 3186</div> 3187 3188<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> 3189 3190 3191<div style="margin: auto;"> 3192 <h4><a name="hald-clut" id="hald-clut"></a>-hald-clut</h4> 3193</div> 3194 3195<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> 3196 3197<p>A Hald color lookup table is a 3-dimensional color cube mapped to 2 3198dimensions. Create it with the <kbd>HALD:</kbd> prefix (e.g. HALD:8). You 3199can apply any color transformation to the Hald image and then use this option 3200to apply the transform to the image. </p> 3201 3202<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png hald.png -hald-clut transform.png</span></p> 3203<p>This option provides a convenient method for you to use Gimp or Photoshop 3204to make color corrections to the Hald CLUT image and subsequently apply them 3205to multiple images using an ImageMagick script. </p> 3206 3207<p>Note that the representation is only of the normal RGB color space and that 3208the whole color value triplet is used for the interpolated lookup of the 3209represented Hald color cube image. Because of this the operation is not <a 3210href="#channel" >-channel</a> setting effected, nor can it adjust or modify an 3211images transparency or alpha/matte channel.</p> 3212 3213<p>See also <a href="#clut" >-clut</a> which provides color value replacement 3214of the individual color channels, usally involving a simplier gray-scale 3215image. E.g: gray-scale to color replacement, or modification by a histogram 3216mapping. </p> 3217 3218 3219<div style="margin: auto;"> 3220 <h4><a name="help" id="help"></a>-help</h4> 3221</div> 3222 3223<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> 3224 3225<div style="margin: auto;"> 3226 <h4><a name="highlight-color" id="highlight-color"></a>-highlight-color <em class="arg">color</em></h4> 3227</div> 3228 3229<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> 3230 3231<div style="margin: auto;"> 3232 <h4><a name="iconGeometry" id="iconGeometry"></a>-iconGeometry <em class="arg">geometry</em></h4> 3233</div> 3234 3235<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> 3236 3237<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> 3238 3239<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> 3240 3241<div style="margin: auto;"> 3242 <h4><a name="iconic" id="iconic"></a>-iconic</h4> 3243</div> 3244 3245<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> 3246 3247<div style="margin: auto;"> 3248 <h4><a name="identify" id="identify"></a>-identify</h4> 3249</div> 3250 3251<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> 3252 3253<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> 3254 3255<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> 3256 3257<p>If <a href="#verbose">-verbose</a> precedes this option, copious 3258amounts of image properties are displayed including image statistics, profiles, 3259image histogram, and others.</p> 3260 3261<div style="margin: auto;"> 3262 <h4><a name="ift" id="ift"></a>-ift</h4> 3263</div> 3264 3265<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> 3266 3267<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" target="_blank">Fourier Transform</a>, <a href="http://en.wikipedia.org/wiki/DFT" target="_blank">Discrete Fourier Transform</a> and <a href="http://en.wikipedia.org/wiki/FFT" target="_blank">Fast Fourier Transform</a>.</p> 3268 3269<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> 3270 3271<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert fft_image.miff -ift fft_image_ift.png</span></p> 3272<p>or</p> 3273 3274<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> 3275 3276<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. 3277 3278<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#ift">-ift</a>. 3279 3280<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. 3281 3282<div style="margin: auto;"> 3283 <h4><a name="immutable" id="immutable"></a>-immutable</h4> 3284</div> 3285 3286<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> 3287 3288<div style="margin: auto;"> 3289 <h4><a name="implode" id="implode"></a>-implode <em class="arg">factor</em></h4> 3290</div> 3291 3292<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> 3293 3294<div style="margin: auto;"> 3295 <h4><a name="insert" id="insert"></a>-insert <em class="arg">index</em></h4> 3296</div> 3297 3298<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> 3299 3300<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> 3301 3302<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> 3303 3304<div style="margin: auto;"> 3305 <h4><a name="intent" id="intent"></a>-intent <em class="arg">type</em></h4> 3306</div> 3307 3308<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> 3309 3310<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> 3311 3312<p>The default intent is undefined.</p> 3313 3314<p>To print a complete list of rendering intents, use <a href="#list">-list intent</a>.</p> 3315 3316<div style="margin: auto;"> 3317 <h4><a name="interlace" id="interlace"></a>-interlace <em class="arg">type</em></h4> 3318</div> 3319 3320<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> 3321 3322<p>Choose from:</p> 3323 3324<pre class="text"> 3325 none 3326 line 3327 plane 3328 partition 3329 JPEG 3330 GIF 3331 PNG 3332</pre> 3333 3334<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> 3335 3336<p><kbd>None</kbd> means do not interlace (RGBRGBRGBRGBRGBRGB...),</p> 3337 3338<p><kbd>Line</kbd> uses scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...), and.</p> 3339 3340<p><kbd>Plane</kbd> uses plane interlacing (RRRRRR...GGGGGG...BBBBBB...).</p> 3341 3342<p><kbd>Partition</kbd> is like plane except the different planes are saved to individual files (e.g. image.R, 3343image.G, and image.B).</p> 3344 3345<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> 3346image.</p> 3347 3348<p>To print a complete list of interlacing schemes, use <a href="#list">-list interlace</a>.</p> 3349 3350<div style="margin: auto;"> 3351 <h4><a name="interpolate" id="interpolate"></a>-interpolate <em class="arg">type</em></h4> 3352</div> 3353 3354<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> 3355 3356<p>When looking up the color of a pixel using a non-integer floating point 3357value, you typically fall in between the pixel colors defined by the source 3358image. This setting determines how the color is determined from the colors of 3359the pixels surrounding that point. That is how to determine the color of a 3360point that falls between two, or even four different colored pixels. </p> 3361 3362<pre class="text"> 3363 integer: The color of the top-left pixel (floor function) 3364 nearest-neighbor: The nearest pixel to the lookup point (rounded function) 3365 average: The average color of the surrounding four pixels 3366 bilinear A double linear interpolation of pixels (the default) 3367 mesh Divide area into two flat triangular interpolations 3368 bicubic Fitted bicubic-spines of surrounding 16 pixels 3369 spline Direct spline curves (colors are blurred) 3370 filter Use resize <a href="#filter">-filter</a> settings 3371</pre> 3372 3373<p>This most important for distortion operators such as <a href="#distort" 3374>-distort</a>, <a href="#implode" >-implode</a>, <a href="#transform" 3375>-transform</a> and <a href="#fx" >-fx</a>. </p> 3376 3377<p>To print a complete list of interpolation methods, use <a href="#list">-list interpolate</a>.</p> 3378 3379<p>See also <a href="#virtual-pixel" >-virtual-pixel</a>, for control of the 3380lookup for positions outside the boundaries of the image. </p> 3381 3382 3383<div style="margin: auto;"> 3384 <h4><a name="interline-spacing" id="interline-spacing"></a>-interline-spacing <em class="arg">value</em></h4> 3385</div> 3386 3387<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> 3388 3389<div style="margin: auto;"> 3390 <h4><a name="interword-spacing" id="interword-spacing"></a>-interword-spacing <em class="arg">value</em></h4> 3391</div> 3392 3393<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> 3394 3395<div style="margin: auto;"> 3396 <h4><a name="kerning" id="kerning"></a>-kerning <em class="arg">value</em></h4> 3397</div> 3398 3399<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> 3400 3401<div style="margin: auto;"> 3402 <h4><a name="label" id="label"></a>-label <em class="arg">name</em></h4> 3403</div> 3404 3405<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> 3406 3407<p>Use this option to assign a specific label to the image, as it is read in 3408or created. You can use the <a href="#set" >-set</a> operation to re-assign 3409a the labels of images already read in. Image formats such as TIFF, PNG, 3410MIFF, supports saving the label information with the image.</p> 3411 3412<p>When saving an image to a <em class="arg">PostScript</em> file, any label 3413assigned to an image is used as a header string to print above the postscript 3414image. </p> 3415 3416<p>You can include the image filename, type, width, height, or other image 3417attribute by embedding special format character. See <a href="/www/escape.html">Format and Print Image 3418Properties</a> for details of the percent escape codes.</p> 3419 3420<p>For example,</p> 3421 3422<p class="crtsnip"> 3423 -label "%m:%f %wx%h" bird.miff 3424</p> 3425 3426<p>assigns an image label of <kbd>MIFF:bird.miff 512x480</kbd> to the 3427"<kbd>bird.miff</kbd>" image and whose width is 512 and height is 480, as it 3428is read in. If a <a href="#label">+label</a> option was used instead, any 3429existing label present in the image would be used. You can remove all labels 3430from an image by assigning the empty string. </p> 3431 3432<p>A label is not drawn on the image, but is embedded in the image datastream 3433via <em>Label</em> tag or similar mechanism. If you want the label to be 3434visible on the image itself, use the <a href="#draw">-draw</a> option, or 3435during the final processing in the creation of a image montage.</p> 3436 3437<p>If the first character of <em class="arg">string</em> is <em 3438class="arg">@</em>, the image label is read from a file titled by the 3439remaining characters in the string. Labels in a file are literal, no embedded 3440formatting characters are recognized.</p> 3441 3442 3443<div style="margin: auto;"> 3444 <h4><a name="lat" 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> 3445</div> 3446 3447<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> 3448 3449<p>Adaptively threshold each pixel based on the value of pixels in a 3450surrounding window. If the current pixel is lighter than this average plus 3451the optional <kbd>offset</kbd>, then it is made white, otherwise it is made 3452black. Small variations in pixel values such as found in scanned documents 3453can be ignored if offset is positive. A negative offset will make it more 3454sensitive to those small variations. </p> 3455 3456<p>This is commonly used to threshold images with an uneven background. It is 3457based on the assumption that average color of the small window is the 3458the local background color, from which to separate the forground color. </p> 3459 3460 3461<div style="margin: auto;"> 3462 <h4><a name="layers" id="layers"></a>-layers <em class="arg">method</em></h4> 3463</div> 3464 3465<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> 3466 3467<p>Perform various image operation methods to a ordered sequence of images 3468which may represent either a set of overlaid 'image layers', a GIF disposal 3469animation, or a fully-'coalesced' animation sequence. </p> 3470 3471<table class="doc"> 3472 <tbody> 3473 <tr valign="top"> 3474 <th align="left" style="width: 8%">Method</th> 3475 <th align="left">Description</th> 3476 </tr> 3477 3478 <tr valign="top"> 3479 <td valign="top">compare-any</td> 3480 <td valign="top">Crop the second and later frames to the smallest rectangle 3481 that contains all the differences between the two images. No GIF <a 3482 href="#dispose" >-dispose</a> methods are taken into account. </td> 3483 </tr> 3484 3485 <tr><td></td><td>This exactly the same as the <a href="#deconstruct" 3486 >-deconstruct</a> operator, and does not preserve animations normal 3487 working, especially when animation used layer disposal methods such as 3488 '<kbd>Previous</kbd>' or '<kbd>Background</kbd>'. </td> 3489 </tr> 3490 3491 <tr valign="top"> 3492 <td valign="top">compare-clear</td> 3493 <td valign="top">As '<kbd>compare-any</kbd>' but crop to the bounds of any 3494 opaque pixels which become transparent in the second frame. That is the 3495 smallest image needed to mask or erase pixels for the next frame. </td> 3496 </tr> 3497 3498 <tr valign="top"> 3499 <td valign="top">compare-overlay</td> 3500 <td valign="top">As '<kbd>compare-any</kbd>' but crop to pixels that add 3501 extra color to the next image, as a result of overlaying color pixels. 3502 That is the smallest single overlaid image to add or change colors. </td> 3503 </tr> 3504 3505 <tr><td></td><td>This can be used with the <a href="#compose" >-compose</a> alpha 3506 composition method '<kbd>change-mask</kbd>', to reduce the image to 3507 just the pixels that need to be overlaid. </td> 3508 </tr> 3509 3510 <tr valign="top"> 3511 <td valign="top">coalesce</td> 3512 <td valign="top">Equivalent to a call to the <a href="#coalesce" 3513 >-coalesce</a> operator. Apply the layer disposal methods set in the 3514 current image sequence to form a fully defined animation sequence, as 3515 it should be displayed. Effectively converting a GIF animation into a 3516 'film strip'-like animation. </td> 3517 </tr> 3518 3519 <tr valign="top"> 3520 <td valign="top">composite</td> 3521 <td valign="top">Alpha Composition of two image lists, separated by a 3522 "<kbd>null:</kbd>" image, with the destination image list first, and 3523 the source images last. An image from each list are composited 3524 together until one list is finished. The separator image and source 3525 image lists are removed. </td> 3526 </tr> 3527 3528 3529 <tr><td></td> 3530 <td>The <a href="#geometry" >-geometry</a> offset is adjusted according 3531 to <a href="#gravity" >-gravity</a> in accordance of the virtual 3532 canvas size of the first image in each list. Unlike a normal <a 3533 href="#composite" >-composite</a> operation, the canvas offset is also 3534 added to the final composite positioning of each image. </td> </tr> 3535 3536 <tr><td></td> 3537 <td>If one of the image lists only contains one image, that image is 3538 applied to all the images in the other image list, regardless of which 3539 list it is. In this case it is the image meta-data of the list which 3540 preserved. </td> 3541 </tr> 3542 3543 3544 <tr valign="top"> 3545 <td valign="top">dispose</td> 3546 <td valign="top">This like '<kbd>coalesce</kbd>' but shows the look of 3547 the animation after the layer disposal method has been applied, before 3548 the next sub-frame image is overlaid. That is the 'dispose' image that 3549 results from the application of the GIF <a href="#dispose" 3550 >-dispose</a> method. This allows you to check what 3551 is going wrong with a particular animation you may be developing. 3552 </td> 3553 </tr> 3554 3555 <tr valign="top"> 3556 <td valign="top">flatten</td> 3557 <td valign="top">Create a canvas the size of the first images virtual 3558 canvas using the current <a href="#background" >-background</a> color, 3559 and <a href="#compose" >-compose</a> each image in turn onto that 3560 canvas. Images falling outside that canvas is clipped. Final 3561 image will have a zero virtual canvas offset. </td> 3562 </tr> 3563 3564 <tr><td></td> 3565 <td>This usally used as one of the final 'image layering' operations 3566 overlaying all the prepared image layers into a final image. </td> 3567 </tr> 3568 3569 <tr><td></td> 3570 <td>For a single image this method can also be used to fillout a virtual 3571 canvas with real pixels, or to underlay a opaque color to remove 3572 transparency from an image.</td> 3573 </tr> 3574 3575 3576 <tr valign="top"> 3577 <td valign="top">merge</td> 3578 <td valign="top">As 'flatten' method but merging all the given image 3579 layers into a new layer image just large enough to hold all the image 3580 without clipping or extra space. The new images virtual offset will 3581 prevere the position of the new layer, even if this offset is 3582 negative. the virtual canvas size of the first image is preserved. 3583 </td> 3584 </tr> 3585 3586 <tr><td></td><td>Caution is advised when handling image layers with negative offsets 3587 as few image file formats handle them correctly. </td> 3588 </tr> 3589 3590 <tr valign="top"> 3591 <td valign="top">mosaic</td> 3592 <td valign="top">As 'flatten' method but expanding the initial canvas size 3593 of the first image so as to hold all the image layers. However as a 3594 virtual canvas is 'locked' to the origin, by definition, image layers 3595 with a negative offsets will still be clipped by the top and left 3596 edges.</td> 3597 </tr> 3598 3599 <tr><td></td><td>This method is commonly used to layout individual image using various 3600 offset but without knowing the final canvas size. The resulting image 3601 will, like 'flatten' not have any virtual offset, so can be saved to 3602 any image file format. </td> 3603 </tr> 3604 3605 3606 <tr valign="top"> 3607 <td valign="top">optimize</td> 3608 <td valign="top">Optimize a coalesced animation, into GIF animation using 3609 a number of general techniques. This currently a short cut to 3610 apply both the '<kbd>optimize-frame</kbd>', and 3611 '<kbd>optimize-transparency</kbd>' methods but may be expanded to 3612 include other optimization methods as they are developed. </td> 3613 </tr> 3614 3615 <tr valign="top"> 3616 <td valign="top">optimize-frame</td> 3617 <td valign="top">Optimize a coalesced animation, into GIF animation by 3618 reducing the number of pixels per frame as much as possible by 3619 attempting to pick the best layer disposal method to use, while ensuring 3620 the result will continue to animate properly. </td> 3621 </tr> 3622 3623 <tr><td></td><td> There is no guarantee that the best optimization is found. But 3624 then no reasonably fast GIF optimization algorithm can do this. 3625 However this does seem to do better than most other GIF frame 3626 optimizers seen. </td> 3627 </tr> 3628 3629 <tr valign="top"> 3630 <td valign="top">optimize-plus</td> 3631 <td valign="top">As '<kbd>optimize-frame</kbd>' but attempt to improve the 3632 overall optimization by adding extra frames to the animation, without 3633 changing the final look or timing of the animation. The frames are 3634 added to attempt to separate the clearing of pixels from the 3635 overlaying of new additional pixels from one animation frame to the 3636 next. If this does not improve the optimization (for the next frame 3637 only), it will fall back to the results of the previous normal 3638 '<kbd>optimize-frame</kbd>' technique. </td> 3639 </tr> 3640 3641 <tr><td></td><td>There is the possibility that the change in the disposal style will 3642 result in a worsening in the optimization of later frames, though this 3643 is unlikely. In other words there no guarantee that it is better than 3644 the normal '<kbd>optimize-frame</kbd>' technique. For some animations 3645 however you can get a vast improvement in the final animation size. </td> 3646 </tr> 3647 3648 <tr valign="top"> 3649 <td valign="top">optimize-transparency</td> 3650 <td valign="top">Given a GIF animation, replace any pixel in the sub-frame 3651 overlay images with transparency, if it does not change the resulting 3652 animation by more than the current <a href="#fuzz" >-fuzz</a> factor. 3653 </td> 3654 </tr> 3655 3656 <tr><td></td><td>This should allow a existing frame optimized GIF animation to compress 3657 into a smaller file size due to larger areas of one (transparent) 3658 color rather than a pattern of multiple colors repeating the current 3659 disposed image of the last frame. </td> 3660 </tr> 3661 3662 <tr valign="top"> 3663 <td valign="top">remove-dups</td> 3664 <td valign="top">Remove (and merge time delays) of duplicate consecutive 3665 images, so as to simplify layer overlays of coalesced animations. 3666 </td> 3667 </tr> 3668 3669 <tr><td></td><td>Usually this a result of using a constant time delay across the 3670 whole animation, or after a larger animation was split into smaller 3671 sub-animations. The duplicate frames could also have been used as 3672 part of some frame optimization methods. </td> 3673 </tr> 3674 3675 <tr valign="top"> 3676 <td valign="top">remove-zero</td> 3677 <td valign="top">Remove any image with a zero time delay, unless ALL the 3678 images have a zero time delay (and is not a proper timed animation, a 3679 warning is then issued). </td> 3680 </tr> 3681 3682 <tr><td></td><td>In a GIF animation, such images are usually frames which provide 3683 partial intermediary updates between the frames that are actually 3684 displayed to users. These frames are usally added for improved frame 3685 optimization in GIF animations. </td> 3686 </tr> 3687 3688 <tr valign="top"> 3689 <td valign="top">trim-bounds</td> 3690 <td valign="top">Find the bounds of all the images in the current 3691 image sequence, then adjust the offsets so all images are contained on 3692 a minimal positive canvas. None of the image data is modified, only 3693 there virtual canvas size and offset. The all the image is given 3694 the same canvas size, and and will have a positive offset, but will 3695 remain in the same position relative to each other. As a result of the 3696 minimal canvas size at least one image will touch every edge of that 3697 canvas. The image data however may be transparent. 3698 </td> 3699 </tr> 3700 3701 </tbody> 3702</table> 3703 3704<p>To print a complete list of layer types, use <a href="#list">-list layers</a>.</p> 3705 3706<p>The operators <a href="#coalesce" >-coalesce</a>, <a href="#deconstruct" 3707>-deconstruct</a>, <a href="#flatten" >-flatten</a>, and <a href="#mosaic" 3708>-mosaic</a> are only aliases for the above methods. Also see <a 3709href="#page" >-page</a>, <a href="#repage" >-repage</a> operators, the <a 3710href="#compose" >-compose</a> setting, and the GIF <a href="#dispose" 3711>-dispose</a> and <a href="#delay" >-delay</a> settings. </p> 3712 3713 3714<div style="margin: auto;"> 3715 <h4><a name="level" 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> 3716</div> 3717 3718<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> 3719 3720<p>Given one, two or three values delimited with commas: black-point, 3721white-point, gamma (for example: 10,250,1.0 or 2%,98%,0.5). The black and 3722white points range from 0 to <em class="QR">QuantumRange</em>, or from 0 to 100%; if the white 3723point is omitted it is set to (<em class="QR">QuantumRange</em> - black_point), so as to center 3724contrast changes. If a <kbd>%</kbd> sign is present anywhere in the string, 3725both black and white points are percentages of the full color range. Gamma 3726will do a <a href="#gamma">-gamma</a> adjustment of the values. If it is 3727omitted, the default of 1.0 (no gamma correction) is assumed.</p> 3728 3729<p>In normal usage (<kbd>-level</kbd>) the image values are stretched so that 3730the given '<kbd>black_point</kbd>' value in the original image is set to 3731zero (or black), while the given '<kbd>white_point</kbd>' value is set to 3732<em class="QR">QuantumRange</em> (or white). This provides you with direct contrast adjustments 3733to the image. The '<kbd>gamma</kbd>' of the resulting image will then be 3734adjusted. </p> 3735 3736<p>From ImageMagick v6.4.1-9 using the plus form of the operator (<kbd>+level</kbd>) or 3737adding the special '!' flag anywhere in the argument list, will cause the 3738operator to do the reverse of the level adjustment. That is a zero, or 3739<em class="QR">QuantumRange</em> value (black, and white, resp.) in the original image, is 3740adjusted to the given level values, allowing you to de-contrast, or compress 3741the channel values within the image. The '<kbd>gamma</kbd>' is adjusted before the level adjustment to de-contrast the image is made. </p> 3742 3743<p>Only the channels defined by the current <a href="#channel">-channel</a> 3744setting are adjusted (defaults to RGB color channels only), allowing you to 3745limit the effect of this operator. </p> 3746 3747<p>Please note that the transparency channel is treated as 'matte' 3748values (0 is opaque) and not as 'alpha' values (0 is transparent).</p> 3749 3750 3751<div style="margin: auto;"> 3752 <h4><a name="level-colors" id="level-colors"></a>-level-colors {<em 3753 class="arg">black_color</em>}{,}{<em class="arg">white_color</em>}</h4> 3754</div> 3755 3756<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> 3757 3758<p>This function is exactly like <a href="#level">-level</a>, except that the 3759value value for each color channel is determined by the 3760'<kbd>black_color</kbd>' and '<kbd>white_color</kbd>' colors given (as 3761described under the <a href="#fill">-fill</a> option). </p> 3762 3763<p>This effectually means the colors provided to <kbd>-level-colors</kbd> 3764is mapped to become 'black' and 'white' respectively, with all the other 3765colors linearly adjusted (or clipped) to match that change. Each channel is 3766adjusted separately using the channel values of the colors specified. </p> 3767 3768<p>On the other hand the plus form of the operator (<kbd>+level-colors</kbd>) 3769will map the image color 'black' and 'white' to the given colors 3770respectively, resulting in a gradient (de-contrasting) tint of the image to 3771those colors. This can also be used to convert a plain gray-scale image into a 3772one using the gradient of colors specified. </p> 3773 3774<p>By supplying a single color with a comma separator either before or after 3775that color, will just replace the respective 'black' or 'white' point 3776respectively. But if no comma separator is provided, the given color is 3777used for both the black and white color points, making the operator either 3778threshold the images around that color (- form) or set all colors to that 3779color (+ form). </p> 3780 3781 3782<div style="margin: auto;"> 3783 <h4><a name="limit" id="limit"></a>-limit <em class="arg">type value</em></h4> 3784</div> 3785 3786<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> 3787 3788<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> 3789 3790<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> 3791 3792<p class="crtsnip"> 3793 -limit memory 32MiB -limit map 64MiB 3794</p> 3795 3796<p>Use <a href="#list">-list resource</a> to list the current limits. For example, our system shows these limits:</p> 3797 3798<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>identify -list resource</span><span class='crtout'><pre>File Area Memory Map Disk Thread Time 3799------------------------------------------------------------------------------ 3800 768 12.404GB 8.6642GiB 23.104GiB 18.446744EB 8 unlimited</pre> 3801</span></p> 3802<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> 3803 3804<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> 3805 3806<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> 3807 3808<p class="crtsnip"> 3809-limit area 10mb 3810</p> 3811 3812<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> 3813 3814<p class="crtsnip"> 3815-limit area 10mb -limit disk 500mb 3816</p> 3817 3818<p>Here ImageMagick stops processing if an image requires more than 500MB of disk storage.</p> 3819 3820<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> 3821 3822<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. 3823</p> 3824 3825<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. 3826</p> 3827 3828<div style="margin: auto;"> 3829 <h4><a name="linear-stretch" 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> 3830</div> 3831 3832<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> 3833 3834<p>This is very similar to <a href="#contrast-stretch" >-contrast-stretch</a>, 3835and uses a 'histogram bin' to determine the range of color values that needs to 3836be stretched. However it then stretchs those colors using the <a 3837href="#level" >-level</a> operator.</p> 3838 3839<p>As such while the initial determination may have 'binning' round off 3840effects, the image colors are stretched mathematically, rather than using the 3841histogram bins. This makes the operator more accurate. </p> 3842 3843<p>note however that a <a href="#linear-stretch" >-linear-stretch</a> of 3844'<kbd>0</kbd>' does nothing, while a value of '<kbd>1</kbd>' does a near 3845perfect stretch of the color range. </p> 3846 3847<p>See also <a href="#auto-level" >-auto-level</a> for a 'perfect' 3848normalization of mathematical images. </p> 3849 3850<p>This operator is under review for re-development. </p> 3851 3852 3853<div style="margin: auto;"> 3854 <h4><a name="linewidth" id="linewidth"></a>-linewidth</h4> 3855</div> 3856 3857<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> 3858 3859<div style="margin: auto;"> 3860 <h4><a name="liquid-rescale" id="liquid-rescale"></a>-liquid-rescale <em class="arg">geometry</em></h4> 3861</div> 3862 3863<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> 3864 3865<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> 3866 3867<div style="margin: auto;"> 3868 <h4><a name="list" id="list"></a>-list <em class="arg">type</em></h4> 3869</div> 3870 3871<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> 3872 3873<pre class="text"> 3874 Align 3875 Alpha 3876 Boolean 3877 Channel 3878 Class 3879 ClipPath 3880 Coder 3881 Color 3882 Colorspace 3883 Command 3884 Compose 3885 Compress 3886 Configure 3887 DataType 3888 Debug 3889 Decoration 3890 Delegate 3891 Direction 3892 Dispose 3893 Distort 3894 Dither 3895 Endian 3896 Evaluate 3897 FillRule 3898 Filter 3899 Font 3900 Format 3901 Function 3902 Gravity 3903 ImageList 3904 Intent 3905 Interlace 3906 Interpolate 3907 Kernel 3908 Layers 3909 LineCap 3910 LineJoin 3911 List 3912 Locale 3913 LogEvent 3914 Log 3915 Magic 3916 Method 3917 Metric 3918 Mime 3919 Mode 3920 Morphology 3921 Module 3922 Noise 3923 Orientation 3924 Policy 3925 PolicyDomain 3926 PolicyRights 3927 Preview 3928 Primitive 3929 QuantumFormat 3930 Resource 3931 SparseColor 3932 Storage 3933 Stretch 3934 Style 3935 Threshold 3936 Type 3937 Units 3938 Validate 3939 VirtualPixel 3940</pre> 3941 3942<p>These lists vary depending on your version of ImageMagick. Use "<kbd>-list 3943list</kbd>" to get a complete listing of all the "<kbd>-list</kbd>" arguments 3944available:</p> 3945 3946<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>identify -list list</span></p> 3947<div style="margin: auto;"> 3948 <h4><a name="log" id="log"></a>-log <em class="arg">string</em></h4> 3949</div> 3950 3951<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> 3952 3953<p>This option specifies the format for the log printed when the <a 3954href="#debug">-debug</a> option is active.</p> 3955 3956<p>You can display the following components by embedding special format 3957characters:</p> 3958 3959<pre class="text"> 3960 %d domain 3961 %e event 3962 %f function 3963 %l line 3964 %m module 3965 %p process ID 3966 %r real CPU time 3967 %t wall clock time 3968 %u user CPU time 3969 %% percent sign 3970 \n newline 3971 \r carriage return 3972</pre> 3973 3974<p>For example:</p> 3975 3976<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> 3977<p>The default behavior is to print all of the components.</p> 3978 3979<div style="margin: auto;"> 3980 <h4><a name="loop" id="loop"></a>-loop <em class="arg">iterations</em></h4> 3981</div> 3982 3983<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> 3984 3985<p>Set iterations to zero to repeat the animation an infinite number of times, 3986otherwise the animation repeats itself up to <em class="arg">iterations</em> 3987times.</p> 3988 3989<div style="margin: auto;"> 3990 <h4><a name="lowlight-color" id="lowlight-color"></a>-lowlight-color <em class="arg">color</em></h4> 3991</div> 3992 3993<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> 3994 3995<div style="margin: auto;"> 3996 <h4><a name="magnify" id="magnify"></a>-magnify <em class="arg">factor</em></h4> 3997</div> 3998 3999<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> 4000 4001 4002<div style="margin: auto;"> 4003 <h4><a name="map" id="map"></a>-map <em class="arg">type</em></h4> 4004</div> 4005 4006<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> 4007 4008<p>Choose from these <em class="arg">Standard Colormap</em> types:</p> 4009 4010<pre class="text"> 4011 best 4012 default 4013 gray 4014 red 4015 green 4016 blue 4017</pre> 4018 4019<p>The <em class="arg">X server</em> must support the <em class="arg">Standard 4020Colormap</em> you choose, otherwise an error occurs. Use <kbd>list</kbd> as 4021the type and <kbd>display</kbd> searches the list of colormap types in 4022<kbd>top-to-bottom</kbd> order until one is located. See <em 4023class="arg">xstdcmap(1)</em> for one way of creating Standard Colormaps.</p> 4024 4025 4026<div style="margin: auto;"> 4027 <h4><a name="map_stream_" id="map_stream_"></a>-map <em class="arg">components</em></h4> 4028</div> 4029 4030<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> 4031 4032<p>Here are the valid components of a map:</p> 4033 4034<pre class="text"> 4035 r red pixel component 4036 g green pixel component 4037 b blue pixel component 4038 a alpha pixel component (0 is transparent) 4039 o opacity pixel component (0 is opaque) 4040 i grayscale intensity pixel component 4041 c cyan pixel component 4042 m magenta pixel component 4043 y yellow pixel component 4044 k black pixel component 4045 p pad component (always 0) 4046</pre> 4047 4048<p>You can specify as many of these components as needed in any order (e.g. 4049bgr). The components can repeat as well (e.g. rgbr).</p> 4050 4051 4052<div style="margin: auto;"> 4053 <h4><a name="mask" id="mask"></a>-mask 4054<em class="arg">filename</em></h4> 4055</div> 4056 4057<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> 4058 4059<p>Use <a href="#mask">+mask</a> to remove the image mask.</p> 4060 4061<div style="margin: auto;"> 4062 <h4><a name="mattecolor" id="mattecolor"></a>-mattecolor <em class="arg">color</em></h4> 4063</div> 4064 4065<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> 4066 4067<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 4068 4069<p>The default matte color is <kbd>#BDBDBD</kbd>, <span 4070style="background-color: #bdbdbd;">this shade of gray</span>.</p> 4071 4072<div style="margin: auto;"> 4073 <h4><a name="maximum" id="maximum"></a>-maximum</h4> 4074</div> 4075 4076<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> 4077 4078<div style="margin: auto;"> 4079 <h4><a name="median" id="median"></a>-median <em class="arg">radius</em></h4> 4080</div> 4081 4082<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> 4083 4084<div style="margin: auto;"> 4085 <h4><a name="metric" id="metric"></a>-metric <em class="arg">type</em></h4> 4086</div> 4087 4088<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> 4089 4090<p>Choose from:</p> 4091 4092<pre class="text"> 4093 AE absolute error count, number of different pixels (-fuzz effected) 4094 MAE mean absolute error (normalized), average channel error distance 4095 MEPP mean error per pixel (normalized mean error, normalized peak error) 4096 MSE mean error squared, average of the channel error squared 4097 PAE peak absolute (normalize peak absolute) 4098 PSNR peak signal to noise ratio 4099 RMSE root mean squared (normalized root mean squared) 4100</pre> 4101 4102<p>The '<kbd>AE</kbd>' or absolute count of pixels that are different, can be 4103controlled using a <a href="#fuzz" >-fuzz</a> factor to ignore pixels which 4104only changed by a small amount. The '<kbd>PAE</kbd>' can be used to find the 4105size of the <a href="#fuzz" >-fuzz</a> factor needed to make all pixels 4106'similar', while '<kbd>MAE</kbd>' can be used to find out the factor needed 4107for about half the pixels to be similar. </p> 4108 4109<p>The '<kbd>MEPP</kbd>' metric returns three different metrics 4110('<kbd>MAE</kbd>', '<kbd>MAE</kbd>' normalized, and '<kbd>PAE</kbd>' 4111normalized) from a single comparison run. </p> 4112 4113<p>To print a complete list of metrics, use the <a href="#list">-list 4114metrics</a> option.</p> 4115 4116 4117<div style="margin: auto;"> 4118 <h4><a name="minimum" id="minimum"></a>-minimum</h4> 4119</div> 4120 4121<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> 4122 4123 4124<div style="margin: auto;"> 4125 <h4><a name="mode" id="mode"></a>-mode <em class="arg">value</em></h4> 4126</div> 4127 4128<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> 4129 4130<p>Choose the <em class="arg">value</em> from these styles: <kbd>Frame, 4131Unframe, or Concatenate</kbd></p> 4132 4133<p>Use the <a href="#list" >-list</a> option with a '<kbd>Mode</kbd>' argument 4134for a list of <a href="#mode" >-mode</a> arguments available in your 4135ImageMagick installation.</p> 4136 4137 4138<div style="margin: auto;"> 4139 <h4><a name="modulate" id="modulate"></a>-modulate <em class="arg">brightness</em>[,<em class="arg">saturation</em>,<em class="arg">hue</em>]</h4> 4140</div> 4141 4142<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 4143class="arg">saturation</em>, and <em class="arg">hue</em> of an image.</td><td style='text-align:right;'></td></tr></table> 4144 4145<p>The arguments are given as a percentages of variation. A value of 100 means 4146no change, and any missing values are taken to mean 100.</p> 4147 4148<p>The <em class="arg">brightness</em> is a multiplier of the overall 4149brightness of the image, so 0 means pure black, 50 is half as bright, 200 is 4150twice as bright. To invert its meaning <a href="#negate">-negate</a> the image 4151before and after. </p> 4152 4153<p>The <em class="arg">saturation</em> controls the amount of color in an 4154image. For example, 0 produce a grayscale image, while a large value such as 4155200 produce a very colorful, 'cartoonish' color.</p> 4156 4157<p>The <em class="arg">hue</em> argument causes a "rotation" of the colors 4158within the image by the amount specified. For example, 50 results in 4159a counter-clockwise rotation of 90, mapping red shades to purple, and so on. 4160A value of either 0 or 200 results in a complete 180 degree rotation of the 4161image. Using a value of 300 is a 360 degree rotation resulting in no change to 4162the original image. </p> 4163 4164<p>For example, to increase the color brightness by 20% and decrease the color 4165saturation by 10% and leave the hue unchanged, use <a 4166href="#modulate">-modulate 120,90</a>.</p> 4167 4168<p>Use <a href="#set">-set</a> attribute of '<kbd 4169class="arg">option:modulate:colorspace</kbd>' to specify which colorspace to 4170modulate. Choose from <kbd>HSB</kbd>, <kbd>HSL</kbd> (the default), or 4171<kbd>HWB</kbd>. For example,</p> 4172 4173<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> 4174 4175<div style="margin: auto;"> 4176 <h4><a name="monitor" id="monitor"></a>-monitor</h4> 4177</div> 4178 4179<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> 4180 4181 4182<div style="margin: auto;"> 4183 <h4><a name="monochrome" id="monochrome"></a>-monochrome</h4> 4184</div> 4185 4186<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> 4187 4188 4189<div style="margin: auto;"> 4190 <h4><a name="morph" id="morph"></a>-morph <em class="arg">frames</em></h4> 4191</div> 4192 4193<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> 4194 4195<p>Both the image pixels and size are linearly interpolated to give the 4196appearance of a meta-morphosis from one image to the next, over all the images 4197in the current image list. The added images are the equivalent of a <a 4198href="#blend">-blend</a> composition. The <em class="arg">frames</em> 4199argument determine how many images to interpolate between each image. </p> 4200 4201 4202<div style="margin: auto;"> 4203 <h4><a name="morphology" id="morphology"></a>-morphology</h4> 4204 <h4><a name="morphology" id="morphology"></a>-morphology <em class="arg">method</em> <em class="arg">kernel</em></h4> 4205</div> 4206 4207<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> 4208 4209Until I get around to writing a option summary for this, see <A 4210HREF="http://www.imagemagick.org/Usage/morphology/" >IM Usage Examples, 4211Morphology</A>. </P> 4212 4213 4214<div style="margin: auto;"> 4215 <h4><a name="mosaic" id="mosaic"></a>-mosaic</h4> 4216</div> 4217 4218<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> 4219 4220 4221<div style="margin: auto;"> 4222 <h4><a name="motion-blur" 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> 4223</div> 4224 4225<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> 4226 4227<p>Blur with the given radius, standard deviation (sigma), and angle. The 4228angle given is the angle toward which the image is blurred. That is the 4229direction people would consider the object is coming from. </p> 4230 4231<p>Note that the blur is not uniform distribution, giving the motion a 4232definite sense of direction of movement. </p> 4233 4234<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 4235pixels which are outside the image proper are blurred into the final result. 4236</p> 4237 4238<div style="margin: auto;"> 4239 <h4><a name="name" id="name"></a>-name</h4> 4240</div> 4241 4242<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> 4243<div style="margin: auto;"> 4244 <h4><a name="negate" id="negate"></a>-negate</h4> 4245</div> 4246 4247<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> 4248 4249<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> 4250 4251<div style="margin: auto;"> 4252 <h4><a name="noise" id="noise"></a>-noise <em class="arg">radius</em><br/> 4253 +noise <em class="arg">type</em></h4> 4254</div> 4255 4256<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> 4257 4258<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> 4259 4260<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> 4261 4262<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> 4263 4264<pre class="text"> 4265Gaussian 4266Impulse 4267Laplacian 4268Multiplicative 4269Poisson 4270Random 4271Uniform 4272</pre> 4273 4274<p>To print a complete list of noises, use the <a href="#list">-list noise</a> option.</p> 4275 4276<p>Also see the <a href="#evaluate">-evaluate</a> noise functions that allos 4277the use of a controlling value to specify teh amount of noise that should be 4278added to an image. </p> 4279 4280 4281<div style="margin: auto;"> 4282 <h4><a name="normalize" id="normalize"></a>-normalize</h4> 4283</div> 4284 4285<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> 4286 4287<p>The intensity values are stretched to cover the entire range of possible 4288values. While doing so, black-out at most <em>2%</em> of the pixels and 4289white-out at most <em>1%</em> of the pixels.</p> 4290 4291<p>Note that as of ImageMagick 6.4.7-0, <a href="#normalize" >-normalize</a> 4292is equivalent to <a href="#contrast-stretch" >-contrast-stretch 2%x1%</a>. 4293(Before this version, it was equivalent to <a href="#contrast-stretch" 4294>-contrast-stretch 2%x99%</a>).</p> 4295 4296<p>All the channels are normalized in concert by the came amount so as to 4297preserve color integrity, when the default <a href="#channel" >+channel</a> 4298setting is in use. Specifying any other <a href="#channel" >-channel</a> 4299setting will normalize the RGB channels independently.</p> 4300 4301<p>See <a href="#contrast-stretch" >-contrast-stretch</A> for more details. 4302Also see <a href="#auto-level" >-auto-level</a> for a 'perfect' normalization 4303that is better suited to mathematically generated images. </p> 4304 4305<p>This operator is under review for re-development. </p> 4306 4307 4308<div style="margin: auto;"> 4309 <h4><a name="ordered-dither" id="ordered-dither"></a>-ordered-dither <em class="arg">threshold_map</em>{,<em class="arg">level</em>...}</h4> 4310</div> 4311 4312<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 4313class="arg">threshold map</em> specified, and a uniform color map with the 4314given number of <em class="arg">levels</em> per color channel . </td><td style='text-align:right;'></td></tr></table> 4315 4316<p>You can choose from these standard threshold maps:</p> 4317 4318<pre class="text"> 4319threshold 1x1 Threshold 1x1 (non-dither) 4320checks 2x1 Checkerboard 2x1 (dither) 4321o2x2 2x2 Ordered 2x2 (dispersed) 4322o3x3 3x3 Ordered 3x3 (dispersed) 4323o4x4 4x4 Ordered 4x4 (dispersed) 4324o8x8 8x8 Ordered 8x8 (dispersed) 4325h4x4a 4x1 Halftone 4x4 (angled) 4326h6x6a 6x1 Halftone 6x6 (angled) 4327h8x8a 8x1 Halftone 8x8 (angled) 4328h4x4o Halftone 4x4 (orthogonal) 4329h6x6o Halftone 6x6 (orthogonal) 4330h8x8o Halftone 8x8 (orthogonal) 4331h16x16o Halftone 16x16 (orthogonal) 4332c5x5b c5x5 Circles 5x5 (black) 4333c5x5w Circles 5x5 (white) 4334c6x6b c6x6 Circles 6x6 (black) 4335c6x6w Circles 6x6 (white) 4336c7x7b c7x7 Circles 7x7 (black) 4337c7x7w Circles 7x7 (white) 4338</pre> 4339 4340<p> The <kbd>checks</kbd> pattern produces a 3 level checkerbord dither 4341pattern. Or you can define your own <em class="arg" >threshold map</em> in a 4342personal or system <kbd>thresholds.xml</kbd> XML file. </p> 4343 4344<p>To print a complete list of threshold, use the <a href="#list" >-list 4345threshold</a> option.</p> 4346 4347<p>It is recommended that the <a href="#map" >+map</a> operator be used after 4348applying <a href="#ordered-dither" >-ordered-dither</a> to reduce the number of 4349colors an animated image sequence, to less that 256 colors. This ensures that 4350a common or global color table is used when saving the result to a color 4351limited file format such as GIF. </p> 4352 4353<p>Note that at this time the exact same threshold dithering map is used for 4354all color channels, no attempt is made to offset or rotate the map for 4355different channels is made, to create an offset printing effect. (possible 4356future expansion) </p> 4357 4358 4359<div style="margin: auto;"> 4360 <h4><a name="opaque" id="opaque"></a>-opaque <em class="arg">color</em></h4> 4361</div> 4362 4363<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> 4364 4365<p>The <em class="arg">color</em> argument is defined using the format 4366described under the <a href="#fill" >-fill</a> option. The <a href="#fuzz" 4367>-fuzz</a> setting can be used to match and replace colors similar to the one 4368given.</p> 4369 4370<p>Use <a href="#opaque">+opaque</a> to paint any pixel that does not match 4371the target color. </p> 4372 4373<p>The <a href="#transparent">-transparent</a> operator is exactly the same 4374as <a href="#opaque" >-opaque</a> but replaces the matching color with 4375transparency rather than the current <a href="#fill">-fill</a> color setting. 4376To ensure that it can do this it also ensures that the image has an alpha 4377channel enabled, as per "<kbd><a href="#alpha" >-alpha</a> set</kbd>", for 4378the new transparent colors, and does not require you to modify the <a 4379href="#channel">-channel</a> to enable alpha channel handling. </p> 4380 4381 4382<div style="margin: auto;"> 4383 <h4><a name="orient" id="orient"></a>-orient <em class="arg">image orientation</em></h4> 4384</div> 4385 4386<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> 4387 4388<p>Choose from these orientations:</p> 4389 4390<pre class="text"> 4391 bottom-left 4392 bottom-right 4393 left-bottom 4394 left-top 4395 right-bottom 4396 right-top 4397 top-left 4398 top-right 4399 undefined 4400</pre> 4401 4402<p>To print a complete list of orientations, use the <a href="#list" >-list 4403orientation</a> option.</p> 4404 4405 4406<div style="margin: auto;"> 4407 <h4><a name="page" id="page"></a>-page <em class="arg">geometry</em><br/> 4408 -page <em class="arg">media</em>[<em class="arg">offset</em>][{<em class="arg">^!<></em>}]<br/> 4409 +page 4410 </h4> 4411</div> 4412 4413<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> 4414 4415<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> 4416 4417<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> 4418 4419<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> 4420<table id="geometryTable" cellpadding="2" cellspacing="0" border="1" width="50%" style="margin-left: auto; margin-right: auto;"> 4421<thead> 4422 <tr valign="top"> 4423 <th align="center"><em class="arg">media</em></th> 4424 <th align="center"><em class="arg">width</em></th> 4425 <th align="center"><em class="arg">height</em></th> 4426 </tr> 4427</thead> 4428<tbody> 4429<tr><td align="left"> 11x17 </td> <td align="right"> 792</td> <td align="right"> 1224</td> </tr> 4430<tr><td align="left"> Ledger </td> <td align="right"> 1224</td> <td align="right"> 792</td> </tr> 4431<tr><td align="left"> Legal </td> <td align="right"> 612</td> <td align="right"> 1008</td> </tr> 4432<tr><td align="left"> Letter </td> <td align="right"> 612</td> <td align="right"> 792</td> </tr> 4433<tr><td align="left"> LetterSmall</td> <td align="right"> 612</td> <td align="right"> 792</td> </tr> 4434<tr><td align="left"> ArchE </td> <td align="right"> 2592</td> <td align="right"> 3456</td> </tr> 4435<tr><td align="left"> ArchD </td> <td align="right"> 1728</td> <td align="right"> 2592</td> </tr> 4436<tr><td align="left"> ArchC </td> <td align="right"> 1296</td> <td align="right"> 1728</td> </tr> 4437<tr><td align="left"> ArchB </td> <td align="right"> 864</td> <td align="right"> 1296</td> </tr> 4438<tr><td align="left"> ArchA </td> <td align="right"> 648</td> <td align="right"> 864</td> </tr> 4439<tr><td align="left"> A0 </td> <td align="right"> 2380</td> <td align="right"> 3368</td> </tr> 4440<tr><td align="left"> A1 </td> <td align="right"> 1684</td> <td align="right"> 2380</td> </tr> 4441<tr><td align="left"> A2 </td> <td align="right"> 1190</td> <td align="right"> 1684</td> </tr> 4442<tr><td align="left"> A3 </td> <td align="right"> 842</td> <td align="right"> 1190</td> </tr> 4443<tr><td align="left"> A4 </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr> 4444<tr><td align="left"> A4Small </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr> 4445<tr><td align="left"> A5 </td> <td align="right"> 421</td> <td align="right"> 595</td> </tr> 4446<tr><td align="left"> A6 </td> <td align="right"> 297</td> <td align="right"> 421</td> </tr> 4447<tr><td align="left"> A7 </td> <td align="right"> 210</td> <td align="right"> 297</td> </tr> 4448<tr><td align="left"> A8 </td> <td align="right"> 148</td> <td align="right"> 210</td> </tr> 4449<tr><td align="left"> A9 </td> <td align="right"> 105</td> <td align="right"> 148</td> </tr> 4450<tr><td align="left"> A10 </td> <td align="right"> 74</td> <td align="right"> 105</td> </tr> 4451<tr><td align="left"> B0 </td> <td align="right"> 2836</td> <td align="right"> 4008</td> </tr> 4452<tr><td align="left"> B1 </td> <td align="right"> 2004</td> <td align="right"> 2836</td> </tr> 4453<tr><td align="left"> B2 </td> <td align="right"> 1418</td> <td align="right"> 2004</td> </tr> 4454<tr><td align="left"> B3 </td> <td align="right"> 1002</td> <td align="right"> 1418</td> </tr> 4455<tr><td align="left"> B4 </td> <td align="right"> 709</td> <td align="right"> 1002</td> </tr> 4456<tr><td align="left"> B5 </td> <td align="right"> 501</td> <td align="right"> 709</td> </tr> 4457<tr><td align="left"> C0 </td> <td align="right"> 2600</td> <td align="right"> 3677</td> </tr> 4458<tr><td align="left"> C1 </td> <td align="right"> 1837</td> <td align="right"> 2600</td> </tr> 4459<tr><td align="left"> C2 </td> <td align="right"> 1298</td> <td align="right"> 1837</td> </tr> 4460<tr><td align="left"> C3 </td> <td align="right"> 918</td> <td align="right"> 1298</td> </tr> 4461<tr><td align="left"> C4 </td> <td align="right"> 649</td> <td align="right"> 918</td> </tr> 4462<tr><td align="left"> C5 </td> <td align="right"> 459</td> <td align="right"> 649</td> </tr> 4463<tr><td align="left"> C6 </td> <td align="right"> 323</td> <td align="right"> 459</td> </tr> 4464<tr><td align="left"> Flsa </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr> 4465<tr><td align="left"> Flse </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr> 4466<tr><td align="left"> HalfLetter </td> <td align="right"> 396</td> <td align="right"> 612</td> </tr> 4467</tbody> 4468</table> 4469 4470 4471 4472 4473<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> 4474 4475<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> 4476 4477<p>The default page dimensions for a TEXT image is 612x792.</p> 4478 4479<p>This option is used in concert with <a href="#density">-density</a>.</p> 4480 4481<p>Use <a href="#page">+page</a> to remove the page settings for an image.</p> 4482 4483<div style="margin: auto;"> 4484 <h4><a name="paint" id="paint"></a>-paint <em class="arg">radius</em></h4> 4485</div> 4486 4487<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> 4488 4489<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> 4490 4491<div style="margin: auto;"> 4492 <h4><a name="path" id="path"></a>-path <em class="arg">path</em></h4></div> 4493 4494<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> 4495 4496<div style="margin: auto;"> 4497 <h4><a name="pause_animate_" id="pause_animate_"></a>-pause <em class="arg">seconds</em></h4> 4498</div> 4499 4500<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> 4501 4502<p>Pause for the specified number of seconds before repeating the animation.</p> 4503 4504<div style="margin: auto;"> 4505 <h4><a name="pause_import_" id="pause_import_"></a>-pause <em class="arg">seconds</em></h4> 4506</div> 4507 4508<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> 4509 4510<p>Pause for the specified number of seconds before taking the next snapshot.</p> 4511 4512<div style="margin: auto;"> 4513 <h4><a name="ping" id="ping"></a>-ping</h4> 4514</div> 4515 4516<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> 4517 4518<div style="margin: auto;"> 4519 <h4><a name="pointsize" id="pointsize"></a>-pointsize <em class="arg">value</em></h4> 4520</div> 4521 4522<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> 4523 4524<div style="margin: auto;"> 4525 <h4><a name="polaroid" id="polaroid"></a>-polaroid <em class="arg">angle</em></h4> 4526</div> 4527 4528<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> 4529 4530<p>Use <kbd>+polaroid</kbd> to rotate the image at a random angle between -15 and +15 degrees.</p> 4531 4532<div style="margin: auto;"> 4533 <h4><a name="posterize" id="posterize"></a>-posterize <em class="arg">levels</em></h4> 4534</div> 4535 4536<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> 4537 4538<div style="margin: auto;"> 4539 <h4><a name="precision" id="precision"></a>-precision <em class="arg">value</em></h4> 4540</div> 4541 4542<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> 4543 4544<div style="margin: auto;"> 4545 <h4><a name="preview" id="preview"></a>-preview <em class="arg">type</em></h4> 4546</div> 4547 4548<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> 4549 4550<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> 4551 4552<pre class="text"> 4553 Rotate 4554 Shear 4555 Roll 4556 Hue 4557 Saturation 4558 Brightness 4559 Gamma 4560 Spiff 4561 Dull 4562 Grayscale 4563 Quantize 4564 Despeckle 4565 ReduceNoise 4566 Add Noise 4567 Sharpen 4568 Blur 4569 Threshold 4570 EdgeDetect 4571 Spread 4572 Shade 4573 Raise 4574 Segment 4575 Solarize 4576 Swirl 4577 Implode 4578 Wave 4579 OilPaint 4580 CharcoalDrawing 4581 JPEG 4582</pre> 4583 4584<p>To print a complete list of previews, use the <a href="#list">-list preview</a> option.</p> 4585 4586<p>The default preview is <kbd>JPEG</kbd>.</p> 4587 4588<div style="margin: auto;"> 4589 <h4><a name="print" id="print"></a>-print <em class="arg">string</em></h4> 4590</div> 4591 4592<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> 4593 4594<div style="margin: auto;"> 4595 <h4><a name="process" id="process"></a>-process <em class="arg">command</em></h4> 4596</div> 4597 4598<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> 4599 4600<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> 4601 4602<div style="margin: auto;"> 4603 <h4><a name="profile" id="profile"></a>-profile <em class="arg">filename</em><br/> 4604 +profile <em class="arg">profile_name</em></h4> 4605</div> 4606 4607<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> 4608 4609<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> 4610 4611<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> 4612 4613<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> 4614 4615<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> 4616 4617<p>For example, to extract the Exif data (which is stored in JPEG files in the <em class="arg">APP1</em> profile), use.</p> 4618 4619<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert cockatoo.jpg profile.exif</span></p> 4620<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> 4621 4622<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert CMYK.tif -profile "CMYK.icc" -profile "RGB.icc" RGB.tiff</span></p> 4623<p>Furthermore, since ICC profiles are not necessarily symmetric, extra conversion steps can yield unwanted results. 4624CMYK profiles are often very asymmetric since they involve 3−>4 and 4−>3 channel mapping. 4625</p> 4626 4627<div style="margin: auto;"> 4628 <h4><a name="quality" id="quality"></a>-quality <em class="arg">value</em></h4> 4629</div> 4630 4631<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> 4632 4633<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> 4634 4635<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> 4636 4637<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> 4638 4639<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> 4640 4641<p>If filter-type is 4 or less, the specified filter-type is used for all scanlines:</p> 4642 4643<pre class="text"> 4644 0: none 4645 1: sub 4646 2: up 4647 3: average 4648 4: Paeth 4649</pre> 4650 4651<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> 4652 4653<p>If filter-type is 6, adaptive filtering with <em class="arg">minimum-sum-of-absolute-values</em> is used.</p> 4654 4655<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> 4656 4657<p>The quality setting has no effect on the appearance of PNG and MNG images, since the compression is always lossless.</p> 4658 4659<p>For further information, see the <a href="http://www.w3.org/pub/WWW/TR">PNG</a> specification.</p> 4660 4661<div style="margin: auto;"> 4662 <h4><a name="quantize" id="quantize"></a>-quantize <em class="arg">colorspace</em></h4> 4663</div> 4664 4665<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> 4666 4667<p>This setting defines the colorspace used to sort out and reduce the number 4668of colors needed by an image (for later dithering) by operators such as <a 4669href="#colors" >-colors</a>, Note that color reducion also happens 4670automatically when saving images to color-limited image file formats, such as 4671GIF, and PNG8.</p> 4672 4673 4674<div style="margin: auto;"> 4675 <h4><a name="quiet" id="quiet"></a>-quiet</h4> 4676</div> 4677 4678<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> 4679 4680<div style="margin: auto;"> 4681 <h4><a name="radial-blur" id="radial-blur"></a>-radial-blur <em class="arg">angle</em></h4> 4682</div> 4683 4684<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> 4685 4686<p>Note that this is actually a rotational blur rather than a radial and as 4687such actually mis-named. </p> 4688 4689<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 4690pixels which are outside the image proper are blurred into the final result. 4691</p> 4692 4693 4694<div style="margin: auto;"> 4695 <h4><a name="raise" id="raise"></a>-raise <em class="arg">thickness</em></h4> 4696</div> 4697 4698<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> 4699 4700<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>. 4701</p> 4702 4703<p>Unlike the similar <a href="#frame">-frame</a> option, <a href="#raise">-raise</a> does not alter the dimensions of the image.</p> 4704 4705<div style="margin: auto;"> 4706 <h4><a name="random-threshold" id="random-threshold"></a>-random-threshold <em class="arg">low</em>x<em class="arg">high</em></h4> 4707</div> 4708 4709<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> 4710 4711<div style="margin: auto;"> 4712 <h4><a name="red-primary" id="red-primary"></a>-red-primary <em class="arg">x,y</em></h4> 4713</div> 4714 4715<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> 4716 4717<div style="margin: auto;"> 4718 <h4><a name="regard-warnings" id="regard-warnings"></a>-regard-warnings</h4> 4719</div> 4720 4721<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> 4722 4723<div style="margin: auto;"> 4724 <h4><a name="remap" id="remap"></a>-remap <em class="arg">filename</em></h4> 4725</div> 4726 4727<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> 4728 4729<p>If the <a href="#dither">-dither</a> setting is enabled (the default) then 4730the given colors are dithered over the image as necessary, otherwise the closest 4731color (in RGB colorspace) is selected to replace that pixel in the image. </p> 4732 4733<p>As a side effect of applying a <a href="#remap">-remap</a> of colors across all 4734images in the current image sequence, all the images will have the same color 4735table. That means that when saved to a file format such as GIF, it will use 4736that color table as a single common or global color table, for all the images, 4737without requiring extra local color tables. </p> 4738 4739<p>Use <a href="#remap">+remap</a> to reduce all images in the current image 4740sequence to use a common color map over all the images. This equivalent to 4741appending all the images together (without extra background colors) and color 4742reducing those images using <a href="#colors">-colors</a> with a 256 color 4743limit, then <a href="#remap">-remap</a> those colors over the original list of 4744images. This ensures all the images follow a single color map. </p> 4745 4746<p>If the number of colors over all the images is less than 256, then <a 4747href="#remap">+remap</a> should not perform any color reduction or dithering, as 4748no color changes are needed. In that case, its only effect is to force the use 4749of a global color table. This recommended after using either <a 4750href="#colors">-colors</a> or <a href="#ordered-dither">-ordered-dither</a> to 4751reduce the number of colors in an animated image sequence. </p> 4752 4753<div style="margin: auto;"> 4754 <h4><a name="region" id="region"></a>-region <em class="arg">geometry</em></h4> 4755</div> 4756 4757<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> 4758 4759<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> 4760 4761<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> 4762 4763<div style="margin: auto;"> 4764 <h4><a name="remote" id="remote"></a>-remote</h4> 4765</div> 4766 4767<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> 4768 4769<p>The only command recognized is the name of an image file to load.</p> 4770 4771<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> 4772 4773<div style="margin: auto;"> 4774 <h4><a name="render" id="render"></a>-render</h4> 4775</div> 4776 4777<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> 4778 4779<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> 4780 4781<div style="margin: auto;"> 4782<h4><a name="repage" id="repage"></a>-repage <em class="arg">geometry</em></h4> 4783</div> 4784 4785<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> 4786 4787<p>This option is like <a href="#page">-page</a> but acts as an image operator 4788rather than a setting. You can separately set the canvas size or the offset 4789of the image on that canvas by only providing those components. </p> 4790 4791<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> 4792 4793<p>If a <kbd>!</kbd> flag is given the offset given is added to the existing 4794offset to move the image relative to its previous position. This useful for 4795animation sequences. </p> 4796 4797<p>A given a canvas size of zero such as '<kbd>0x0</kbd>' forces it to 4798recalculate the canvas size so the image (at its current offset) will appear 4799completely on that canvas (unless it has a negative offset).</p> 4800 4801<p>Use <a href="#repage">+repage</a> to completely remove/reset the virtual 4802canvas meta-data from the images. </p> 4803 4804<p>The <a href="#set">-set</a> '<kbd>page</kbd>' option can be used to 4805directly assign virtual canvas meta-data. </p> 4806 4807 4808<div style="margin: auto;"> 4809 <h4><a name="resample" id="resample"></a>-resample <em class="arg">horizontal</em>x<em class="arg">vertical</em></h4> 4810</div> 4811 4812<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> 4813 4814<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> 4815 4816<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> 4817 4818<div style="margin: auto;"> 4819 <h4><a name="resize" id="resize"></a>-resize <em class="arg">geometry</em></h4> 4820</div> 4821 4822<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> 4823 4824<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> 4825 4826<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> 4827 4828<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> 4829 4830<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> 4831<div style="margin: auto;"> 4832 <h4><a name="respect-parentheses" id="respect-parentheses"></a>-respect-parentheses</h4> 4833</div> 4834 4835<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> 4836 4837<div style="margin: auto;"> 4838 <h4><a name="reverse" id="reverse"></a>-reverse</h4> 4839</div> 4840 4841<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> 4842 4843 4844<div style="margin: auto;"> 4845 <h4><a name="roll" id="roll"></a>-roll {<em class="arg">+-</em>}<em class="arg">x</em>{<em class="arg">+-</em>}<em class="arg">y</em></h4> 4846</div> 4847 4848<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> 4849 4850<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> 4851 4852 4853<div style="margin: auto;"> 4854 <h4><a name="rotate" id="rotate"></a>-rotate <em class="arg">degrees</em>{<em class="arg"><</em>}{<em class="arg">></em>}</h4> 4855</div> 4856 4857<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> 4858 4859<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> 4860 4861<p>Empty triangles in the corners, left over from rotating the image, are 4862filled with the <kbd>background</kbd> color. </p> 4863 4864<p>See also the <a href="#distort">-distort</a> operator and specifically the 4865'<kbd>ScaleRotateTranslate</kbd>' distort method. </p> 4866 4867 4868<div style="margin: auto;"> 4869 <h4><a name="sample" id="sample"></a>-sample <em class="arg">geometry</em></h4> 4870</div> 4871 4872<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> 4873 4874<p>Change the image size simply by directly sampling the pixels original 4875image. When magnifying, pixels are replicated in blocks. When minifying, 4876pixels are sub-sampled (i.e., some rows and columns are skipped over). </p> 4877 4878<p>The results are thus equivalent to using <a href="#resize">-resize</a> with 4879a <a href="#filter">-filter</a> setting of <kbd>point</kbd> (nearest 4880neighbour), though <a href="#sample">-sample</a> is a lot faster, as it 4881avoids all the filter processing of the image. As such it completely ignores 4882the current <a href="#filter">-filter</a> setting. </p> 4883 4884<p>The key feature of the <a href="#sample">-sample</a> is that no new colors 4885will be added to the resulting image, though some colors may disappear. </p> 4886 4887<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 4888ignored, unlike <a href="#resize">-resize</a>. </p> 4889 4890 4891<div style="margin: auto;"> 4892 <h4><a name="sampling-factor" id="sampling-factor"></a>-sampling-factor <em class="arg">horizontal-factor</em>x<em class="arg">vertical-factor</em></h4> 4893</div> 4894 4895<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> 4896 4897<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> 4898 4899<div style="margin: auto;"> 4900 <h4><a name="scale" id="scale"></a>-scale <em class="arg">geometry</em></h4> 4901</div> 4902 4903<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> 4904 4905<p>Change the image size simply by replacing pixels by averaging pixels 4906together when minifying, or replacing pixels when magnifing. </p> 4907 4908<p>The results are thus equivalent to using <a href="#resize">-resize</a> with 4909a <a href="#filter">-filter</a> setting of <kbd>box</kbd>. Though it is a lot 4910faster, as it avoids all the filter processing of the image. As such it 4911completely ignores the current <a href="#filter">-filter</a> setting. </p> 4912 4913<p>If when shrinking (minifying) images the original image is some integer 4914multiple of the new image size, the number of pixels avergaed together to 4915produce the new pixel color is the same across the whole image. This is 4916a special case known as 'binning' and is often used as a method of reducing 4917noise in image such as those generated by digital cameras, especially in low 4918light conditions. </p> 4919 4920 4921<div style="margin: auto;"> 4922 <h4><a name="scene" id="scene"></a>-scene <em class="arg">value</em></h4> 4923</div> 4924 4925<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> 4926 4927<p>This option sets the scene number of an image or the first image in an image sequence.</p> 4928 4929<div style="margin: auto;"> 4930 <h4><a name="screen" id="screen"></a>-screen</h4> 4931</div> 4932 4933<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> 4934 4935<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> 4936 4937<div style="margin: auto;"> 4938 <h4><a name="seed" id="seed"></a>-seed</h4> 4939</div> 4940 4941<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> 4942 4943<div style="margin: auto;"> 4944 <h4><a name="segment" id="segment"></a>-segment <em class="arg">cluster-threshold</em>x<em class="arg">smoothing-threshold</em></h4> 4945</div> 4946 4947<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> 4948 4949<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> 4950 4951<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> 4952 4953<p>If the <a href="#verbose">-verbose</a> setting is defined, a detailed report 4954of the color clusters is returned.</p> 4955 4956 4957<div style="margin: auto;"> 4958 <h4><a name="selective-blur" id="selective-blur"></a>-selective-blur <em class="arg">geometry</em></h4> 4959</div> 4960 4961<div style="margin: auto;"> 4962 <h4><a name="selective-blur" id="selective-blur"></a>-selective-blur <em class="arg">radius</em><br />-unsharp <em class="arg">radius</em>x<em class="arg">sigma</em>{<em class="arg">+threshold</em>}</h4> 4963</div> 4964 4965<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> 4966 4967<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> 4968 4969<div style="margin: auto;"> 4970 <h4><a name="separate" id="separate"></a>-separate</h4> 4971</div> 4972 4973<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> 4974 4975<div style="margin: auto;"> 4976 <h4><a name="sepia-tone" id="sepia-tone"></a>-sepia-tone <em class="arg">threshold</em></h4> 4977</div> 4978 4979<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> 4980 4981<p>Specify <em class="arg">threshold</em> as the percent threshold of the intensity (0 - 99.9%).</p> 4982 4983<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> 4984 4985 4986 4987<div style="margin: auto;"> 4988 <h4><a name="set" id="set"></a>-set <em class="arg">key value</em></h4> 4989 <h4><a name="set" id="set"></a>+set <em class="arg">key</em></h4> 4990</div> 4991 4992<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 4993image sequence.</td><td style='text-align:right;'></td></tr></table> 4994 4995<p>This will assign (or modify) specific settings attached to all the images 4996in the current image sequence. Using the <a href="#set">+set</a> form of the 4997option will either remove, or reset that setting to a default state, as 4998appropriate. </p> 4999 5000<p>For example, it will modify specific well known image meta-data 5001'attributes' such as those normally overridden by: the options <a 5002href="#delay" >-delay</a>, <a href="#dispose" >-dispose</a>, and <a 5003href="#page" >-page</a>, <a href="#colorspace" >-colorspace</a>; generally 5004assigned before the image is read in, by using a <em class="arg">key</em> of 5005the same name. </p> 5006 5007<p>If the given <em class="arg">key</em> does not match a specific known 5008'attribute ', such as shown above, the setting is stored as a a free form 5009'properity' string. Such settings are listed in <a href="#verbose" 5010>-verbose</a> information ("<kbd>info:</kbd>" output format) as "Properties". 5011</p> 5012 5013<p>This includes string 'properities' that are set by and assigned to images 5014using the options <a href="#comment" >-comment</a>, <a href="#label" 5015>-label</a>, <a href="#caption" >-caption</a>. These options actually assign 5016a global 'artifact' which are automatically assigned (and any <a href="/www/escape.html" >Format Percent 5017Escapes</a> expanded) to images as they are read in. For example:</p> 5018 5019<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> 5020<p>The set value can also make use of <a href="/www/escape.html" >Format and Print Image 5021Properties</a> in the defined value. For example:</p> 5022 5023<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> 5024<p>Other well known 'properities' that can be include: 5025'<kbd>date:create</kbd>' and '<kbd>date:modify</kbd>' and 5026'<kbd>signature</kbd>'. </p> 5027 5028<p>The <a href="#repage">-repage</a> operator will also allow you to modify 5029the '<kbd>page</kbd>' attribute of an image for images already in memory (also 5030see <a href="#repage">-page</a>). However it is designed to provide a finer 5031control of the sub-parts of this 'attribute'. The <a href="#set">-set page</a> 5032option will only provide a direct, unmodified assignment of '<kbd>page</kbd>' 5033attribute. </p> 5034 5035<p>This option can also associate a colorspace or profile with your image. 5036For example,</p> 5037 5038<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> 5039<p>Some 'properties' must be defined in a specific way to be used. For 5040example only 'properties' prefixed with "<kbd>filename:</kbd>" can be used to 5041modify the output filename of an image. For example</p> 5042 5043<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -set filename:mysize '%wx%h' 'rose_%[filename:mysize].png'</span></p> 5044<p>If the setting value is prefixed with "<kbd>option:</kbd>" the setting will 5045be saved as a global "Artifact" exactly as if it was set using the <a 5046href="#define" >-define</a> option. As such settings are globel in scope, they 5047can be used to pass 'attributes' and 'properities' of one specific image, 5048in a way that allows you to use them in a completely different image, even if 5049the original image has long since been modified or destroyed. For example: </p> 5050 5051<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> 5052<p>Note that <a href="/www/escape.html" >Format Percent Escapes</a> will only match 5053a 'artifact' if the given <em class="arg">key</em> does not match an existing 5054'attribute' or 'properity'. </p> 5055 5056<p>You can set the attributes of the image registry by prefixing the value 5057with <kbd>registry:</kbd>.</p> 5058 5059 5060 5061<div style="margin: auto;"> 5062 <h4><a name="shade" id="shade"></a>-shade <em class="arg">azimuth</em>x<em class="arg">elevation</em></h4> 5063</div> 5064 5065<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> 5066 5067<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> 5068 5069<div style="margin: auto;"> 5070 <h4><a name="shadow" 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> 5071</div> 5072 5073<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> 5074 5075<div style="margin: auto;"> 5076 <h4><a name="shared-memory" 5077id="shared-memory"></a>-shared-memory</h4> 5078</div> 5079 5080<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> 5081 5082<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> 5083 5084<div style="margin: auto;"> 5085 <h4><a name="sharpen" id="sharpen"></a>-sharpen <em class="arg">radius</em>{x<em class="arg">sigma</em>}</h4> 5086</div> 5087 5088<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> 5089 5090<p>Use a Gaussian operator of the given radius and standard deviation (sigma).</p> 5091 5092<div style="margin: auto;"> 5093 <h4><a name="shave" id="shave"></a>-shave <em class="arg">geometry</em></h4> 5094</div> 5095 5096<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> 5097 5098<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> 5099 5100<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> 5101 5102<div style="margin: auto;"> 5103 <h4><a name="shear" id="shear"></a>-shear <em class="arg">Xdegrees</em>[x<em class="arg">Ydegrees</em>]</h4> 5104</div> 5105 5106<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> 5107 5108<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> 5109 5110<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> 5111 5112<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> 5113 5114<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> 5115 5116<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> 5117<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> 5118 5119<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert logo: -shear 20x60 logo-sheared.png</span></p> 5120<div style="margin: auto;"> 5121 <h4><a name="sigmoidal" id="sigmoidal-contrast"></a>-sigmoidal-contrast <em class="arg">contrast</em>x<em class="arg">mid-point</em></h4> 5122</div> 5123 5124<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> 5125 5126<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> 5127 5128<div style="margin: auto;"> 5129 <h4><a name="silent" id="silent"></a>-silent</h4> 5130</div> 5131 5132<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> 5133 5134<div style="margin: auto;"> 5135 <h4><a name="size" id="size"></a>-size <em class="arg">width</em>[x<em class="arg">height</em>][<em class="arg">+offset</em>]</h4> 5136</div> 5137 5138<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> 5139 5140<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> 5141 5142<p>For Photo CD images, choose from these sizes:</p> 5143 5144<pre class="text"> 5145 192x128 5146 384x256 5147 768x512 5148 1536x1024 5149 3072x2048 5150</pre> 5151 5152<div style="margin: auto;"> 5153 <h4><a name="sketch" 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> 5154</div> 5155 5156<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> 5157 5158<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> 5159 5160<div style="margin: auto;"> 5161 <h4><a name="snaps" id="snaps"></a>-snaps <em class="arg">value</em></h4> 5162</div> 5163 5164<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> 5165 5166<p>Use this option to grab more than one image from the X server screen, to create an animation sequence.</p> 5167 5168<div style="margin: auto;"> 5169 <h4><a name="solarize" id="solarize"></a>-solarize <em class="arg">threshold</em></h4> 5170</div> 5171 5172<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> 5173 5174<p>Specify <em class="arg">factor</em> as the percent threshold of the intensity (0 - 99.9%).</p> 5175 5176<p>This option produces a <em class="arg">solarization</em> effect seen when exposing a photographic film to light during the development process.</p> 5177 5178<div style="margin: auto;"> 5179 <h4><a name="sparse-color" id="sparse-color"></a>-sparse-color <em 5180 class="arg">method</em> '<em class="arg">x</em>,<em class="arg">y</em> <em class="arg">color</em> ...'</h4> 5181</div> 5182 5183<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> 5184 5185 5186<table class="doc"> 5187 <tbody> 5188 <tr valign="top"> 5189 <th align="left" style="width: 8%">Method</th> 5190 <th align="left">Description</th> 5191 </tr> 5192 5193 <tr valign="top"> 5194 <td valign="top">voronoi</td> 5195 <td valign="top">Simply map each pixel to the to nearest color point 5196 given. The result are polygonal 'cells' of solid color. </td> 5197 </tr> 5198 5199 <tr valign="top"> 5200 <td valign="top">shepards</td> 5201 <td valign="top">Colors points biased on the ratio of inverse distance 5202 squared. Generating spots of color in a sea of the average of 5203 colors. </td> 5204 </tr> 5205 5206 <tr valign="top"> 5207 <td valign="top">barycentric</td> 5208 <td valign="top">three point triangle of color given 3 points. 5209 Giving only 2 points will form a linear gradient between those points. 5210 Gradient is however not restricted to just the triangle or line. </td> 5211 </tr> 5212 5213 <tr valign="top"> 5214 <td valign="top">bilinear</td> 5215 <td valign="top">Like barycentric but for 4 points. Less than 4 points 5216 fall back to barycentric. </td> 5217 </tr> 5218 5219 </tbody> 5220</table> 5221 5222<p>The points are placed according to the images location on the virtual 5223canvas (<a href="#page" >-page</a> or <a href="#repage" >-repage</a> 5224offset), and do not actually have to exist on the given image, but may be 5225some point beyond the edge of the image. All points are floating point values. 5226</p> 5227 5228<p>Only the color channels defined by the <a href="#channel" >-channel</a> are 5229modified, whcih means the matte/alpha transparency channel is not effected by 5230default. If enabled, the image also needs a the matte/alpha channel to be 5231enabled for this operator to effect an images transparency. This is typical 5232transparency handling for images. </p> 5233 5234<p>All the above methods when given a single point of color will replace all 5235the colors in the image with the color given, regardless of the point. This is 5236logical, and provides an alternative technique to recolor a image to some 5237default value. </p> 5238 5239 5240<div style="margin: auto;"> 5241 <h4><a name="splice" id="splice"></a>-splice <em class="arg">geometry</em></h4> 5242</div> 5243 5244<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> 5245 5246<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> 5247 5248<div style="margin: auto;"> 5249 <h4><a name="spread" id="spread"></a>-spread <em class="arg">amount</em></h4> 5250</div> 5251 5252<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> 5253 5254<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> 5255 5256<div style="margin: auto;"> 5257 <h4><a name="stegano" id="stegano"></a>-stegano <em class="arg">offset</em></h4> 5258</div> 5259 5260<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> 5261 5262<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> 5263 5264<div style="margin: auto;"> 5265 <h4><a name="stereo" id="stereo"></a>-stereo <em class="arg">+x</em>{<em class="arg">+y</em>}</h4> 5266</div> 5267 5268<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> 5269 5270<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> 5271 5272<div style="margin: auto;"> 5273 <h4><a name="storage-type" id="storage-type"></a>-storage-type <em class="arg">type</em></h4> 5274</div> 5275 5276<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> 5277 5278<pre class="text"> 5279 char store pixels as unsigned characters 5280 double store pixels as doubles 5281 float store pixels as floats 5282 integer store pixels as integers 5283 long store pixels as longs 5284 quantum store pixels in the native depth of your ImageMagick distribution 5285 short store pixels as unsigned shorts 5286</pre> 5287 5288<p>Float and double types are normalized from 0.0 to 1.0 otherwise the pixels 5289values range from 0 to the maximum value the storage type can support.</p> 5290 5291<div style="margin: auto;"> 5292 <h4><a name="stretch" id="stretch"></a>-stretch <em class="arg">fontStretch</em></h4> 5293</div> 5294 5295<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> 5296 5297<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> 5298 5299<pre class="text"> 5300 Any 5301 Condensed 5302 Expanded 5303 ExtraCondensed 5304 ExtraExpanded 5305 Normal 5306 SemiCondensed 5307 SemiExpanded 5308 UltraCondensed 5309 UltraExpanded 5310</pre> 5311 5312<p>To print a complete list of stretch types, use <a href="#list">-list stretch</a>.</p> 5313 5314<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> 5315 5316<div style="margin: auto;"> 5317 <h4><a name="strip" id="strip"></a>-strip</h4> 5318</div> 5319 5320<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> 5321 5322<div style="margin: auto;"> 5323 <h4><a name="stroke" id="stroke"></a>-stroke <em class="arg">color</em></h4> 5324</div> 5325 5326<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> 5327 5328<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 5329 5330<p>See <a href="#draw">-draw</a> for further details.</p> 5331 5332<div style="margin: auto;"> 5333 <h4><a name="strokewidth" id="strokewidth"></a>-strokewidth <em class="arg">value</em></h4> 5334</div> 5335 5336<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> 5337 5338<p>See <a href="#draw">-draw</a> for further details.</p> 5339 5340<div style="margin: auto;"> 5341 <h4><a name="style" id="style"></a>-style <em class="arg">fontStyle</em></h4> 5342</div> 5343 5344<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> 5345 5346<p>This setting suggests a font style that ImageMagick should try to apply to 5347the currently selected font family. Select <em class="arg">fontStyle</em> from 5348the following.</p> 5349 5350<pre class="text"> 5351 Any 5352 Italic 5353 Normal 5354 Oblique 5355</pre> 5356 5357<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> 5358 5359<div style="margin: auto;"> 5360 <h4><a name="subimage-search" id="subimage-search"></a>-subimage-search</h4> 5361</div> 5362 5363<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> 5364 5365<p>This option is required to have compare search for the best match location 5366of a small image within a larger image. This search will produce two images 5367(or two frames). The first is the "difference" image and the second will 5368be the "match score" image.</p> 5369 5370<p>The "match-score" image is smaller containing a pixel for ever possible 5371position of the top-left corner of the given sub-image. that is its size will 5372be the size of the larger_image - sub_image + 1. The brightest location in 5373this image is the location s the locate on the best match that is also 5374reported. Note that this may or may nor be a perfect match, and the actual 5375brightness will reflect this. Other bright 'peaks' can be used to locate other 5376possible matching loctions. </p> 5377 5378<p>Note that the search will try to compare teh sub-image at every possible 5379location in the larger image, as such it can be very slow. The smaller the 5380sub-image the faster this search is. </p> 5381 5382 5383<div style="margin: auto;"> 5384 <h4><a name="swap" id="swap"></a>-swap <em class="arg">index,index</em></h4> 5385</div> 5386 5387<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> 5388 5389<p>For example, <a href="#swap">-swap 0,2</a> swaps the first and the third 5390images in the current image sequence. Use <a href="#swap">+swap</a> to switch 5391the last two images in the sequence.</p> 5392 5393<div style="margin: auto;"> 5394 <h4><a name="swirl" id="swirl"></a>-swirl <em class="arg">degrees</em></h4> 5395</div> 5396 5397<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> 5398 5399<p><em class="arg">Degrees</em> defines the tightness of the swirl.</p> 5400 5401<div style="margin: auto;"> 5402 <h4><a name="synchronize" id="synchronize"></a>-synchronize</h4> 5403</div> 5404 5405<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> 5406 5407<div style="margin: auto;"> 5408 <h4><a name="taint" id="taint"></a>-taint</h4> 5409</div> 5410 5411<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> 5412 5413<div style="margin: auto;"> 5414 <h4><a name="text-font" id="text-font"></a>-text-font <em class="arg">name</em></h4> 5415</div> 5416 5417<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> 5418 5419<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> 5420 5421<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> 5422 5423<div style="margin: auto;"> 5424 <h4><a name="texture" id="texture"></a>-texture <em class="arg">filename</em></h4> 5425</div> 5426 5427<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> 5428 5429<div style="margin: auto;"> 5430 <h4><a name="threshold" id="threshold"></a>-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 5431</div> 5432 5433<!-- {<em class="arg">green,blue,opacity</em>} 5434<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> 5435--> 5436 5437<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> 5438 5439<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> 5440 5441<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. 5442</p> 5443 5444<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> 5445 5446<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert in.png -channel red -threshold 50% out.png</span></p> 5447<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> 5448 5449 5450<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> 5451<p>Note that the values of the transparency channel is treated as 'matte' 5452values (0 is opaque) and not as 'alpha' values (0 is transparent).</p> 5453 5454<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>. 5455</p> 5456 5457<div style="margin: auto;"> 5458 <h4><a name="thumbnail" id="thumbnail"></a>-thumbnail <em class="arg">geometry</em></h4> 5459</div> 5460 5461<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> 5462 5463<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> 5464 5465<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> 5466 5467<div style="margin: auto;"> 5468 <h4><a name="tile" id="tile"></a>-tile <em class="arg">filename</em></h4> 5469</div> 5470 5471<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> 5472 5473<div style="margin: auto;"> 5474 <h4>-tile <em class="arg">geometry</em></h4> 5475</div> 5476 5477<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> 5478 5479<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> 5480 5481<div style="margin: auto;"> 5482 <h4>-tile</h4> 5483</div> 5484 5485<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> 5486 5487<div style="margin: auto;"> 5488 <h4><a name="tile-offset" 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> 5489</div> 5490 5491<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> 5492 5493<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> 5494 5495<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> 5496 5497<div style="margin: auto;"> 5498 <h4><a name="tint" id="tint"></a>-tint <em class="arg">value</em></h4> 5499</div> 5500 5501<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> 5502 5503<p>Tint the image with the fill color.</p> 5504 5505<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> 5506 5507<div style="margin: auto;"> 5508 <h4><a name="title" id="title"></a>-title <em class="arg">string</em></h4> 5509</div> 5510 5511<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> 5512 5513<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> 5514 5515<p>For example,</p> 5516 5517<p class="crtsnip"> 5518 -title "%m:%f %wx%h" 5519</p> 5520 5521<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> 5522 5523 5524<div style="margin: auto;"> 5525 <h4><a name="transform" id="transform"></a>-transform</h4> 5526</div> 5527 5528<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> 5529 5530<p>This option applies the transformation matrix from a previous <a href="#affine">-affine</a> option.</p> 5531 5532<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> 5533 5534<p>This operator has been now been superseded by the <a 5535href="#distort">-distort</a> '<kbd>AffineProjection</kbd>' method. </p> 5536 5537 5538<div style="margin: auto;"> 5539 <h4><a name="transparent" id="transparent"></a>-transparent <em class="arg">color</em></h4> 5540</div> 5541 5542<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> 5543 5544<p>The <em class="arg">color</em> argument is defined using the format 5545described under the <a href="#fill">-fill</a> option. The <a href="#fuzz" 5546>-fuzz</a> setting can be used to match and replace colors similar to the one 5547given. </p> 5548 5549<p>Use <a href="#transparent" >+transparent</a> to invert the pixels matched. 5550that is make all non-matching colors transparent. </p> 5551 5552<p>The <a href="#opaque">-opaque</a> operator is exactly the same as <a 5553href="#transparent" >-transparent</a> but replaces the matching color with the 5554current <a href="#fill">-fill</a> color setting, rather than transparent. 5555However the <a href="#transparent" >-transparent</a> operator also ensures 5556that the image has an alpha channel enabled, as per "<kbd><a href="#alpha" 5557>-alpha</a> set</kbd>", and does not require you to modify the <a 5558href="#channel">-channel</a> to enable alpha channel handling. </p> 5559 5560<p>Note that this does not define the color as being the 'transparency color' 5561used for color-mapped image formats, such as GIF. For that use <a 5562href="#transparent-color" >-transparent-color</a> </p> 5563 5564 5565<div style="margin: auto;"> 5566 <h4><a name="transparent-color" id="transparent-color"></a>-transparent-color <em class="arg">color</em></h4> 5567</div> 5568 5569<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> 5570 5571<p>Sometimes this is used for saving to image formats such as 5572GIF and PNG8 which uses this color to represent boolean transparency. This 5573does not make a color transparent, it only defines what color the transparent 5574color is in the color palette of the saved image. Use <a 5575href="#transparent">-transparent</a> to make an opaque color transparent.</p> 5576 5577<p>This option allows you to have both an opaque visible color, as well as a 5578transparent color of the same color value without conflict. That is, you can 5579use the same color for both the transparent and opaque color areas within an 5580image. This, in turn, frees to you to select a transparent color that is 5581appropriate when an image is displayed by an application that does not handle a 5582transparent color index, while allowing ImageMagick to correctly handle images of this 5583type. </p> 5584 5585<p>The default transparent color is <kbd>#00000000</kbd>, which is fully transparent black.</p> 5586 5587<div style="margin: auto;"> 5588 <h4><a name="transpose" id="transpose"></a>-transpose</h4> 5589</div> 5590 5591<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> 5592 5593<p> This option mathematically transposes the pixel array. It is equivalent to the sequence <kbd>-flip -rotate 90</kbd>. 5594</p> 5595 5596<div style="margin: auto;"> 5597 <h4><a name="transverse" id="transverse"></a>-transverse</h4> 5598</div> 5599 5600<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> 5601 5602 5603<div style="margin: auto;"> 5604 <h4><a name="treedepth" id="treedepth"></a>-treedepth <em class="arg">value</em></h4> 5605</div> 5606 5607<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> 5608 5609<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> 5610 5611<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> 5612 5613<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> 5614 5615<div style="margin: auto;"> 5616 <h4><a name="trim" id="trim"></a>-trim</h4> 5617</div> 5618 5619<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> 5620 5621<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> 5622 5623<p>The page or virtual canvas information of the image is preserved allowing 5624you to extract the result of the <a href="#trim">-trim</a> operation from the 5625image. Use a <a href="#repage">+repage</a> to remove the virtual canvas page 5626information if it is unwanted.</p> 5627 5628<p>If the trimmed image 'disappears' an warning is produced, and a special 5629single pixel transparent 'missed' image is returned, in the same way as when a 5630<a href="#crop">-crop</a> operation 'misses' the image proper. </p> 5631 5632 5633<div style="margin: auto;"> 5634 <h4><a name="type" id="type"></a>-type <em class="arg">type</em></h4> 5635</div> 5636 5637<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> 5638 <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>, <kbd>ColorSeparationMatte</kbd>, or <kbd>Optimize</kbd>.</p> 5639 5640<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> 5641 5642<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert bird.png -type TrueColor bird.jpg</span></p> 5643<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> 5644 5645<p>Use <a href="#type">-type optimize</a> to ensure the image is written in the smallest possible file size.</p> 5646 5647<div style="margin: auto;"> 5648 <h4><a name="undercolor" id="undercolor"></a>-undercolor <em class="arg">color</em></h4> 5649</div> 5650 5651<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> 5652 5653<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 5654 5655<p>See <a href="#draw">-draw</a> for further details.</p> 5656 5657 5658<div style="margin: auto;"> 5659 <h4><a name="update" id="update"></a>-update <em class="arg">seconds</em></h4> 5660</div> 5661 5662<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> 5663 5664<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> 5665 5666 5667<div style="margin: auto;"> 5668 <h4><a name="unique-colors" id="unique-colors"></a>-unique-colors</h4> 5669</div> 5670 5671<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> 5672 5673 5674<div style="margin: auto;"> 5675 <h4><a name="units" id="units"></a>-units <em class="arg">type</em></h4> 5676</div> 5677 5678<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> 5679 5680<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> 5681 5682 5683<div style="margin: auto;"> 5684 <h4><a name="unsharp" 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> 5685</div> 5686 5687<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> 5688 5689<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> 5690 5691<p>The parameters are:</p> 5692 5693<pre class="text"> 5694 radius: The radius of the Gaussian, in pixels, not counting the center 5695 pixel (default 0). 5696 sigma: The standard deviation of the Gaussian, in pixels (default 1.0). 5697 amount: The fraction of the difference between the original and the blur 5698 image that is added back into the original (default 1.0). 5699 threshold: The threshold, as a fraction of <em class="QR">QuantumRange</em>, needed to apply the 5700 difference amount (default 0.05). 5701</pre> 5702 5703 5704<div style="margin: auto;"> 5705 <h4><a name="verbose" id="verbose"></a>-verbose</h4> 5706</div> 5707 5708<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> 5709 5710 5711<div style="margin: auto;"> 5712 <h4><a name="version" id="version"></a>-version</h4> 5713</div> 5714 5715<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> 5716 5717 5718<div style="margin: auto;"> 5719 <h4><a name="view" id="view"></a>-view <em class="arg">string</em></h4> 5720</div> 5721 5722<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> 5723 5724 5725<div style="margin: auto;"> 5726 <h4><a name="vignette" 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> 5727</div> 5728 5729<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> 5730 5731 5732<div style="margin: auto;"> 5733 <h4><a name="virtual-pixel" id="virtual-pixel"></a>-virtual-pixel <em class="arg">method</em></h4> 5734</div> 5735 5736<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> 5737 5738<p>This option defines what color source should be used if and when a color 5739lookup completely 'misses' the source image. The color(s) that appear to 5740surround the source image. Generally this color is derived from the source 5741image, but could also be set to a specify background color. </p> 5742 5743<p>Choose from these methods:</p> 5744 5745<pre class="text"> 5746 background: the area surrounding the image is the background color 5747 black: the area surrounding the image is black 5748 checker-tile: alternate squares with image and background color 5749 dither: non-random 32x32 dithered pattern 5750 edge: extend the edge pixel toward infinity 5751 gray: the area surrounding the image is gray 5752 horizontal-tile: horizontally tile the image, background color above/below 5753 horizontal-tile-edge: horizontally tile the image and replicate the side edge pixels 5754 mirror: mirror tile the image 5755 random: choose a random pixel from the image 5756 tile: tile the image (default) 5757 transparent: the area surrounding the image is transparent blackness 5758 vertical-tile: vertically tile the image, sides are background color 5759 vertical-tile-edge: vertically tile the image and replicate the side edge pixels 5760 white: the area surrounding the image is white 5761</pre> 5762 5763<p>The default value is "edge".</p> 5764 5765<p>This most important for distortion operators such as <a href="#distort" 5766>-distort</a>, <a href="#implode" >-implode</a>, and <a href="#fx" >-fx</a>. 5767However it also effects operations that may access pixels just outside the 5768image proper, such as <a href="#convolve">-convolve</a>, <a 5769href="#blur">-blur</a>, and <a href="#sharpen">-sharpen</a>. </p> 5770 5771<p>To print a complete list of virtual pixel types, use the <a href="#list">-list virtual-pixel</a> option.</p> 5772 5773 5774<div style="margin: auto;"> 5775 <h4><a name="visual" id="visual"></a>-visual <em class="arg">type</em></h4> 5776</div> 5777 5778<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> 5779 5780<p>Choose from these visual classes:</p> 5781 5782<pre class="text"> 5783 StaticGray 5784 GrayScale 5785 StaticColor 5786 PseudoColor 5787 TrueColor 5788 DirectColor 5789 default 5790 visual id 5791</pre> 5792 5793<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> 5794 5795 5796<div style="margin: auto;"> 5797 <h4><a name="watermark" id="watermark"></a>-watermark <em 5798 class="arg">brightness</em>x<em class="arg">saturation</em></h4> 5799</div> 5800 5801<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 5802saturation.</td><td style='text-align:right;'>[<a href="/www/composite.html">composite</a>]</td></tr></table> 5803 5804<p>Take a grayscale image (with alpha mask) and modify the destination image's 5805brightness according to watermark image's grayscale value and the <em 5806class="arg">brightness</em> percentage. The destinations color saturation 5807attribute is just direct modified by the <em class="arg">saturation</em> 5808percentage, which defaults to 100 percent (no color change). </p> 5809 5810 5811<div style="margin: auto;"> 5812 <h4><a name="wave" id="wave"></a>-wave <em class="arg">amplitude</em><br />-wave <em class="arg">amplitude</em>x<em class="arg">wavelength</em></h4> 5813</div> 5814 5815<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> 5816 5817<p>Specify <em class="arg">amplitude</em> and <em class="arg">wavelength</em> of the wave.</p> 5818 5819<div style="margin: auto;"> 5820 <h4><a name="weight" id="weight"></a>-weight <em class="arg">fontWeight</em></h4> 5821</div> 5822 5823<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> 5824 5825<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> 5826 5827<table class="doc"> 5828 <col width="25%" /> 5829 <col width="75%" /> 5830 <thead> 5831 <tr> 5832 <th><em class="arg">fontWeight</em></th> 5833 <th>Description</th> 5834 </tr> 5835 </thead> 5836 <tbody> 5837 <tr><td>All </td> <td>No effect. </td></tr> 5838 <tr><td>Bold </td> <td>Same as <em class="arg">fontWeight</em> = 700.</td></tr> 5839 <tr><td>Bolder </td> <td>Add 100 to font weight if currently ≤ 800.</td></tr> 5840 <tr><td>Lighter </td> <td>Subtract 100 to font weight if currently ≤ 100.</td></tr> 5841 <tr><td>Normal </td> <td>Same as <em class="arg">fontWeight</em> = 400.</td></tr> 5842 </tbody> 5843 </table> 5844 5845<p>To print a complete list of weight types, use <a href="#list">-list weight</a>.</p> 5846 5847<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> 5848 5849<div style="margin: auto;"> 5850 <h4><a name="white-point" id="white-point"></a>-white-point <em class="arg">x,y</em></h4> 5851</div> 5852 5853<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> 5854 5855<div style="margin: auto;"> 5856 <h4><a name="white-threshold" id="white-threshold"></a>-white-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 5857</div> 5858 5859<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> 5860 5861<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. 5862</p> 5863 5864<div style="margin: auto;"> 5865 <h4><a name="window" id="window"></a>-window <em class="arg">id</em></h4> 5866</div> 5867 5868<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> 5869 5870<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> 5871 5872<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> 5873 5874<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> 5875 5876<div style="margin: auto;"> 5877 <h4><a name="window-group" id="window-group"></a>-window-group</h4> 5878</div> 5879 5880<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> 5881 5882<div style="margin: auto;"> 5883 <h4><a name="write" id="write"></a>-write <em class="arg">filename</em></h4> 5884</div> 5885 5886<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> 5887 <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> 5888 5889<p>Use <a href="#compress">-compress</a> to specify the type of image compression.</p> 5890 5891 5892</div> 5893 5894<div id="linkbar"> 5895 <span id="linkbar-west"> </span> 5896 <span id="linkbar-center"> 5897 <a href="http://www.imagemagick.org/discourse-server/">Discourse Server</a> • 5898 <a href="http://www.imagemagick.org/MagickStudio/scripts/MagickStudio.cgi">Studio</a> 5899 </span> 5900 <span id="linkbar-east"> </span> 5901 </div> 5902 <div class="footer"> 5903 <span id="footer-west">© 1999-2010 ImageMagick Studio LLC</span> 5904 <span id="footer-east"> <a href="http://www.imagemagick.org/script/contact.php">Contact the Wizards</a></span> 5905 </div> 5906 <div style="clear: both; margin: 0; width: 100%; "></div> 5907 <script type="text/javascript"> 5908 var _gaq = _gaq || []; 5909 _gaq.push(['_setAccount', 'UA-17690367-1']); 5910 _gaq.push(['_trackPageview']); 5911 5912 (function() { 5913 var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; 5914 ga.src = ('https:' == document.location.protocol ? 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