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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#recolor">‑recolor</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#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#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> 161 162<p>Below is list of command-line options recognized by the ImageMagick <a href="/www/command-line-tools.html">command-line tools</a>. If you want a description of a particular option, click on the option name in the navigation bar above and you will go right to it. Unless otherwise noted, each option is recognized by the commands 163<a href="/www/convert.html">convert</a>, <a href="/www/mogrify.html">mogrify</a>, and .... </p> 164 165<div style="margin: auto;"> 166 <h4><a name="adaptive-blur" id="adaptive-blur"></a>-adaptive-blur <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4> 167</div> 168 169<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> 170 171<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> 172 173<div style="margin: auto;"> 174 <h4><a name="adaptive-resize" id="adaptive-resize"></a>-adaptive-resize <em class="arg">geometry</em></h4> 175</div> 176 177<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> 178 179<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> 180 181<div style="margin: auto;"> 182 <h4><a name="adaptive-sharpen" id="adaptive-sharpen"></a>-adaptive-sharpen <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4> 183</div> 184 185<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> 186 187<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> 188 189<div style="margin: auto;"> 190 <h4><a name="adjoin" id="adjoin"></a>-adjoin</h4> 191</div> 192 193<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> 194 195<p>This option is enabled by default. An attempt is made to save all 196images of an image sequence into the given output file. 197However, some formats, such as JPEG and PNG, do not support more than one 198image per file, and in that case ImageMagick is forced to write each image as a separate file. As 199such, if more than one image needs to be written, the filename given is 200modified by adding a <a href="#scene">-scene</a> number before the 201suffix, in order to make distinct names for each image. </p> 202 203<p>Use <a href="#adjoin">+adjoin</a> to force each image to be written 204to separate files, whether or not the file format allows multiple images 205per file (for example, GIF, MIFF, and TIFF). </p> 206 207<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> 208 209<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert logo: rose: -morph 15 my%02dmorph.jpg</span></p> 210<p>will create a sequence of 17 images named my00morph.jpg, my01morph.jpg, my02morph.jpg, ..., my16morph.jpg. 211</p> 212 213<p>In summary, ImageMagick tries to write all images to one file, but will use 214multiple files if either (1) the output image's file format does not allow multi-image files, 215(2) the <a href="#adjoin">+adjoin</a> option is given, or (3) a C-style integer format string is 216present in the output filename. </p> 217 218 219<div style="margin: auto;"> 220 <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/> 221 -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> 222</div> 223 224<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> 225 226<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> 227 228<p>The matrix entries are entered as comma-separated numeric values <i>with no spaces</i>. </p> 229 230<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> 231 232<div class="eqn"> 233<img alt="affine transformation" src="/images/affine.png"/> 234</div> 235 236<p> 237The 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> 238 239<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> 240 241<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> 242 243<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> 244 245<p class="crtsnip"> 246 -affine <em class="arg">s<sub>x</sub></em>,0,0,<em class="arg">s<sub>y</sub></em> 247</p> 248 249<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> 250 251<p class="crtsnip"> 252 -affine 1,0,0,1,<em class="arg">t<sub>x</sub></em>,<em class="arg">t<sub>y</sub></em> 253</p> 254 255<p>Rotate clockwise about the origin (the upper left-hand corner) by an angle <em>a</em> by letting 256<em>c</em> = cos(<em>a</em>), <em>s</em> = sin(<em>a</em>), and using the following.</p> 257 258<p class="crtsnip"> 259 -affine <em>c</em>,<em>s</em>,-<em>s</em>,<em>c</em> 260</p> 261 262<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> 263 264<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> 265 266<div style="margin: auto;"> 267 <h4><a name="alpha" id="alpha"></a>-alpha <em class="arg">type</em></h4> 268</div> 269 270<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> 271 272<p>Used to set a flag on an image indicating whether or not to use existing alpha 273channel 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> 274 275 276<table class="doc"> 277 <tbody> 278 <tr valign="top"> 279 <th align="left" style="width: 8%">type</th> 280 <th align="left">Description</th> 281 </tr> 282 283 <tr valign="top"> 284 <td valign="top"><kbd>Off</kbd> or 285 <kbd>Deactivate</kbd></td> 286 <td valign="top"> 287 Disables the image's transparency channel. Does not delete or change the 288 existing data, just turns off the use of that data. This is the same as 289 the older <a href="#matte" >+matte</a> operator. </td></tr> 290 291 <tr valign="top"> 292 <td valign="top"><kbd>On</kbd> or 293 <kbd>Activate</kbd></td> 294 <td valign="top"> 295 Enables the image's use of transparency. If transparency data does not 296 already exist, allocates the data and sets it to opaque. If the image has 297 transparency data, the channel is enabled and the transparency data is not changed or modified in any way. This is NOT 298 the same as the older <a href="#matte" >-matte</a> operator. </td></tr> 299 300 <tr valign="top"> 301 <td valign="top"><kbd>Set</kbd></td> 302 <td valign="top"> 303 Turns '<kbd>On</kbd>' the alpha/matte channel and if it was previously 304 turned off resets the channel to opaque. If the image already had the 305 alpha channel turned on, it will have no effect. This is the same as the older <a href="#matte">-matte</a> operator. </td></tr> 306 307 <tr valign="top"> 308 <td valign="top"><kbd>Opaque</kbd></td> 309 <td valign="top"> 310 Turns '<kbd>On</kbd>' the alpha/matte channel and forces it to be fully 311 opaque. </td></tr> 312 313 <tr valign="top"> 314 <td valign="top"><kbd>Transparent</kbd></td> 315 <td valign="top"> 316 Turns '<kbd>On</kbd>' the alpha/matte channel and forces it to be fully 317 transparent. This effectively creates a fully transparent image the same 318 size as the original and with all its original RGB data still intact. </td></tr> 319 320 <tr valign="top"> 321 <td valign="top"><kbd>Extract</kbd></td> 322 <td valign="top"> 323 Copies the alpha channel values into all the color channels and turns 324 '<kbd>Off</kbd>' the the image's transparency, so as to generate a 325 gray-scale mask of the image's shape. This is the inverse of 326 '<kbd>Copy</kbd>'. </td></tr> 327 328 <tr valign="top"> 329 <td valign="top"><kbd>Copy</kbd></td> 330 <td valign="top"> 331 Turns '<kbd>On</kbd>' the alpha/matte channel, then copies the 332 gray-scale intensity of the image, as an alpha mask, into the alpha 333 channel, converting a gray-scale mask into a transparent shaped image 334 ready to be colored appropriately. The color channels are not modified. 335 </td></tr> 336 337 <tr valign="top"> 338 <td valign="top"><kbd>Shape</kbd></td> 339 <td valign="top"> 340 As per '<kbd>Copy</kbd>' but also colors the resulting shape mask with 341 the current background color. 342 </td></tr> 343 344 <tr valign="top"> 345 <td valign="top"><kbd>Background</kbd></td> 346 <td valign="top"> 347 Set any fully-transparent pixel to the background color. 348 </td></tr> 349 </tbody> 350</table> 351 352<p>Note that while the <a href="#matte" >+matte</a> operation is the same as 353"<kbd><a href="#alpha" >-alpha</a> off</kbd>", the <a href="#matte" 354>-matte</a> operation is the same as "<kbd><a href="#alpha" >-alpha</a> set</kbd>" and 355not "<kbd><a href="#alpha" >-alpha</a> on</kbd>". 356That is, "<kbd><a href="#alpha" >-alpha</a> set</kbd>" will ensure that the 357written image is opaque if the original image had no transparency 358channel enabled, regardless if transparency data is already present. </p> 359 360 361<div style="margin: auto;"> 362 <h4><a name="annotate" id="annotate"></a> 363 -annotate <em class="arg">degrees</em> <em class="arg">text</em><br /> 364 -annotate <em class="arg">Xdegrees</em>x<em class="arg">Ydegrees</em> <em class="arg">text</em><br /> 365 -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> 366</div> 367 368<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> 369 370<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> 371 372 373<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> 374 375<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> 376 377<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> 378<div class="eqn"><img alt="annotate transformation" src="/images/annotate.png"/></div> 379 380<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> 381 382<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> 383 384<div style="margin: auto;"> 385 <h4><a name="antialias" id="antialias"></a>-antialias</h4> 386</div> 387 388<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 389drawing fonts and lines.</td><td style='text-align:right;'></td></tr></table> 390 391<p>By default, objects (e.g. text, lines, polygons, etc.) are antialiased when 392drawn. Use <a href="#antialias">+antialias</a> to disable the addition of 393antialiasing edge pixels. This will then reduce the number of colors added to 394an image to just the colors being directly drawn. That is, no mixed colors 395will be added when drawing such objects. </p> 396 397<div style="margin: auto;"> 398 <h4><a name="append" id="append"></a>-append</h4> 399</div> 400 401<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> 402 403<p>This option creates a single longer image image, by joining all the current 404images in sequence top-to-bottom. Use <a href="#append">+append</a> to 405stack images left-to-right. </p> 406 407<p>If they are not of the same width, narrower images are padded with the 408current <a href="#background">-background</a> color setting, and their 409position relative to each other can be controled by the current <a 410href="#gravity">-gravity</a> setting. </p> 411 412 413<div style="margin: auto;"> 414 <h4><a name="attenuate" id="attenuate"></a>-attenuate <em class="arg">value</em></h4> 415</div> 416 417<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> 418 419 420<div style="margin: auto;"> 421 <h4><a name="authenticate" id="authenticate"></a>-authenticate <em class="arg">password</em></h4> 422</div> 423 424<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> 425 426<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> 427 428<p>For a different encryption method, see <a href="#encipher">-encipher</a> and <a href="#decipher">-decipher</a>. </p> 429 430 431 432<div style="margin: auto;"> 433 <h4><a name="auto-gamma" id="auto-gamma"></a>-auto-gamma</h4> 434</div> 435 436<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> 437 438<p>This calculates the mean values of an image, then applies a calculated <a 439href="#gamma" >-gamma</a> adjustment so that is the mean color exists in the 440image it will get a have a value of 50%. </p> 441 442<p>This means that any solid 'gray' image will become 50% gray. </p> 443 444<p>This works well for real-life images with little or no extreme dark and 445light areas, but tend to fail for images with large amounts of bright sky or 446dark shadows. It also does not work well for diagrmas or cartoon like images. 447</p> 448 449<p>It uses the <a href="#channel" >-channel</a> setting, (including the 450'<CODE>sync</CODE>' flag for channel syncronization), to determine which color 451values will be used and modified. As the default <a href="#channel" 452>-channel</a> setting is '<CODE>RGB,sync</CODE>', channels will be modified 453together by the same gamma value, preserving colors. </p> 454 455 456 457<div style="margin: auto;"> 458 <h4><a name="auto-level" id="auto-level"></a>-auto-level</h4> 459</div> 460 461<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> 462 463<p>This is a 'perfect' image normalization operator. It finds the exact 464mimimum and maximum color values in the image and then applies a <a 465href="#level" >-level</a> operator to stretch the values to the full range of 466values. </p> 467 468<p>The operator is not typically used for real-life images, image scans, or 469JPEG format images, as a single 'out-rider' pixel can set a bad min/max values 470for the <a href="#level" >-level</a> operation. On the other hand it is the 471right operator to use for color stretching gradient images being used to 472generate Color lookup tables, distortion maps, or other 'mathematically' 473defined images. </p> 474 475<p>The operator is very similar to the <a href="#normalize">-normalize</a>, <a 476href="#contrast-stretch" >-contrast-stretch</a>, and <a href="#linear-stretch" 477>-linear-stretch</a> operators, but without 'histogram binning' or 'clipping' 478problems that these operators may have. That is <a href="#auto-level" 479>-auto-level</a> is the perfect or ideal version these operators. </p> 480 481<p>It uses the <a href="#channel" >-channel</a> setting, (including the 482special '<CODE>sync</CODE>' flag for channel syncronization), to determine 483which color values will be used and modified. As the default <a 484href="#channel" >+channel</a> setting is '<CODE>RGB,sync</CODE>', the 485'<CODE>sync</CODE>' will ensure that the color channels will be modified 486together by the same gamma value, preserving colors, and ignoring 487transparency. </p> 488 489 490 491<div style="margin: auto;"> 492 <h4><a name="auto-orient" id="auto-orient"></a>-auto-orient</h4> 493</div> 494 495<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> 496 497<p>This operator reads and resets the EXIF image profile setting 'Orientation' 498and then performs the appropriate 90 degree rotation on the image to orient 499the image, for correct viewing. </p> 500 501<p>This EXIF profile setting is usually set using a gravity sensor in digital 502camara, however photos taken directly downward or upward may not have an 503appropriate value. Also images that have been orientation 'corrected' without 504reseting this setting, may be 'corrected' again resulting in a incorrect 505result. If the he EXIF profile was previously stripped, the <a 506href="#auto-orient" >-auto-orient</a> operator will do nothing. </p> 507 508 509<div style="margin: auto;"> 510 <h4><a name="average" id="average"></a>-average</h4> 511</div> 512 513<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> 514 515<p>An error results if the images are not identically sized.</p> 516 517 518<div style="margin: auto;"> 519 <h4><a name="backdrop" id="backdrop"></a>-backdrop</h4> 520</div> 521 522<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> 523 524<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> 525 526<div style="margin: auto;"> 527 <h4><a name="background" id="background"></a>-background <em class="arg">color</em></h4> 528</div> 529 530<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> 531 532<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> 533 534<div style="margin: auto;"> 535 <h4><a name="bench" id="bench"></a>-bench <em class="arg">iterations</em></h4> 536</div> 537 538<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> 539 540<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> 541 542<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> 543<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> 544 545<div style="margin: auto;"> 546 <h4><a name="bias" id="bias"></a>-bias <em class="arg">value</em>{<em class="arg">%</em>}</h4> 547</div> 548 549<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> 550 551<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> 552 553<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> 554 555<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 556negative results without clipping to the color value range 557(0..QuantumRange).</p> 558 559<p>See the discussion on HDRI implementations of ImageMagick on the page 560<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. 561</p> 562 563<div style="margin: auto;"> 564 <h4><a name="black-point-compensation" id="black-point-compensation"></a>-black-point-compensation</h4> 565</div> 566 567<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> 568 569<div style="margin: auto;"> 570 <h4><a name="black-threshold" id="black-threshold"></a>-black-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 571</div> 572 573<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> 574 575<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. 576</p> 577 578 579<div style="margin: auto;"> 580 <h4><a name="blend" id="blend"></a>-blend <em class="arg">percent</em></h4> 581</div> 582 583<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 percent.</td><td style='text-align:right;'>[<a href="/www/composite.html">composite</a>]</td></tr></table> 584 585<p>Blend will average the images together ('plus') according to the 586percentages given and each pixels transparency. If only a single percentage 587value is given it sets the weight of the composite or 'source' image, while 588the background image is weighted by the exact opposite amount. That is a 589<kbd>-blend 30</kbd> merges 30% of the 'source' image with 70% of the 590'destination' image. Thus it is equivalent to <kbd>-blend 30x70</kbd>.</p> 591 592 593<div style="margin: auto;"> 594 <h4><a name="blue-primary" id="blue-primary"></a>-blue-primary <em class="arg">x</em>,<em class="arg">y</em></h4> 595</div> 596 597<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> 598 599<div style="margin: auto;"> 600 <h4><a name="blue-shift" id="blue-shift"></a>-blue-shift <em class="arg">factor</em></h4> 601</div> 602 603<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> 604 605<div style="margin: auto;"> 606 607<div style="margin: auto;"> 608 <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> 609</div> 610 611<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> 612 613<p>Convolve the image with a Gaussian or normal distribution. The formula is:</p> 614 615<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="/images/gaussian-blur.png"/> 616</div> 617 618<p>Where <i>r</i> is the blur radius (<i>r</i><sup>2</sup> = <i>u</i><sup>2</sup> + <i>v</i><sup>2</sup>), and σ is the standard deviation of the Gaussian distribution. As a guideline, set <i>r</i> to approximately 3σ. If a radius of 0 is specified, ImageMagick selects a suitable radius for you.</p> 619 620<p>This option differs from <a href="#gaussian-blur">-gaussian-blur</a> simply by taking advantage of the separability properties of the distribution. Here we apply a single-dimensional Gaussian matrix in the horizontal direction, then repeat the process in the vertical direction.</p> 621 622<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 623pixels which are outside the image proper are blurred into the final result. 624</p> 625 626 627<div style="margin: auto;"> 628 <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> 629</div> 630 631<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> 632 633<p>Each pixel in the overlaid region is replaced with an Elliptical Weighted 634Average (EWA) of the source image, scaled according to the grayscale 635mapping. </p> 636 637<p>The ellipse is weighted with sigma set to the given <em class="arg" 638>Width</em> and <em class="arg" >Height</em>. The <em class="arg" >Height</em> 639defaults to the <em class="arg" >Width</em> for a normal circular Guassian 640weighting. The <em class="arg" >Angle</em> will rotate the ellipse from 641horizontal clock-wise. </p> 642 643<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 644pixels which are outside the image proper are blurred into the final result. 645</p> 646 647 648<div style="margin: auto;"> 649 <h4><a name="border" id="border"></a>-border <em class="arg">geometry</em></h4> 650</div> 651 652<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> 653 654<p>Set the width and height using the <em class="arg">size</em> portion of the <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 ignored. </p> 655 656<p>Set the border color by preceding with the <a href="#bordercolor">-bordercolor</a> setting.</p> 657 658<p>See also the <a href="#frame">-frame</a> option, which has more functionality.</p> 659 660<div style="margin: auto;"> 661 <h4><a name="bordercolor" id="bordercolor"></a>-bordercolor <em class="arg">color</em></h4> 662</div> 663 664<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> 665 666<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 667 668<p>The default border color is <kbd>#DFDFDF</kbd>, <span style="background-color: #dfdfdf;">this shade of gray</span>.</p> 669 670<div style="margin: auto;"> 671 <h4><a name="borderwidth" id="borderwidth"></a>-borderwidth <em class="arg">geometry</em> </h4> 672</div> 673 674<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> 675 676<div style="margin: auto;"> 677 <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> 678</div> 679 680<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> 681 682<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> 683 684<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> 685 686<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> 687 688<p>The slope varies from 0 at contrast=-100 to almost vertical at contrast=+100. For brightness=0 and contrast=-100, the result will be 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 will be a a very steep vertical line at mid gray.</p> 689 690<p>Negative slopes, i.e. negating the image, are not possible with this function. All achievable slopes will be zero or positive.</p> 691 692<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 will be totally white. Similarly, when contrast=0 and brightness=-100, the result will be totally black.</p> 693 694<p>As the range of values for the arguments are -100 to +100, adding the '%' symbol will be no different than leaving it off.</p> 695 696<div style="margin: auto;"> 697 <h4><a name="cache" id="cache"></a>-cache <em class="arg">threshold</em></h4> 698</div> 699 700<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> 701 702<div style="margin: auto;"> 703 <h4><a name="caption" id="caption"></a>-caption <em class="arg">string</em></h4> 704</div> 705 706<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> 707 708<div style="margin: auto;"> 709 <h4><a name="cdl" id="cdl"></a>-cdl <em class="arg">filename</em></h4> 710</div> 711 712<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> 713 714<p>Here is an example color correction collection:</p> 715 716<pre class="text"> 717<?xml version="1.0" encoding="UTF-8"?> 718<ColorCorrectionCollection xmlns="urn:ASC:CDL:v1.2"> 719 <ColorCorrection id="cc06668"> 720 <SOPNode> 721 <Slope> 0.9 1.2 0.5 </Slope> 722 <Offset> 0.4 -0.5 0.6 </Offset> 723 <Power> 1.0 0.8 1.5 </Power> 724 </SOPNode> 725 <SATNode> 726 <Saturation> 0.85 </Saturation> 727 </SATNode> 728 </ColorCorrection> 729</ColorCorrectionCollection> 730</pre> 731 732<div style="margin: auto;"> 733 <h4><a name="channel" id="channel"></a>-channel <em class="arg">type</em></h4> 734</div> 735 736<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> 737 738<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> 739 740<p>To print a complete list of channel types, use <a href="#list">-list channel</a>.</p> 741 742<p>The channels above can be specified as a comma-separated list or can be 743abbreviated as a concatenation of the letters '<kbd>R</kbd>', '<kbd>G</kbd>', 744'<kbd>B</kbd>', '<kbd>A</kbd>', '<kbd>O</kbd>', '<kbd>C</kbd>', 745'<kbd>M</kbd>', '<kbd>Y</kbd>', '<kbd>K</kbd>'. 746 747For example, to negate only the alpha channel of an image, use</p> 748<p class="crtsnip"> 749 -channel Alpha -negate 750</p> 751 752Some operators also allow the use of a special channel flag 753'<code>sync</code>'. If present operators that understand this flag will 754apply the exact same image modification to all the image channels in the image 755so as to ensure that colors are kept 'in-sync'. Without this flag such 756operators will apply there function to each channel separately. See <a 757href="#auto-level">-auto-level</a> and <a href="#auto-gamma">-auto-gamma</a> 758for examples of such an operator. </p> 759 760 761<p>By default, ImageMagick sets <a href="#channel">-channel</a> to the value 762'<kbd>RGB,sync</kbd>', which specifies that operators act on all channels 763except the opacity channel, and that all the color channels are to be modified 764in exactly the same way. The 'plus' form <a href="#channel" >+channel</a> 765will reset the value back to this default. </p> 766 767<p>Options that are affected by the <a href="#channel" >-channel</a> setting 768include the following. 769 770<a href="#auto-gamma">-auto-gamma</a>, 771<a href="#auto-level">-auto-level</a>, 772<a href="#black-threshold">-black-threshold</a>, 773<a href="#blur">-blur</a>, 774<a href="#clamp">-clamp</a>, 775<a href="#clut">-clut</a>, 776<a href="#combine">-combine</a>, 777<a href="#contrast-stretch">-contrast-stretch</a>, 778<a href="#evaluate">-evaluate</a>, 779<a href="#function">-function</a>, 780<a href="#fx">-fx</a>, 781<a href="#gaussian-blur">-gaussian-blur</a>, 782<a href="#hald-clut">-hald-clut</a>, 783<a href="#motion-blur">-motion-blur</a>, 784<a href="#negate">-negate</a>, 785<a href="#normalize">-normalize</a>, 786<a href="#ordered-dither">-ordered-dither</a>, 787<a href="#radial-blur">-radial-blur</a>, 788<a href="#random-threshold">-random-threshold</a>, 789<a href="#separate">-separate</a>, and 790<a href="#threshold">-threshold</a>, and 791<a href="#white-threshold">-white-threshold</a>. 792</p> 793 794<p>Warning, some operators behave differentally when the <a href="#channel" 795>+channel</a> default setting is in effect, verses ANY user defined <a 796href="#channel" >-channel</a> setting (including the equivelent of the 797default). For example <a href="#threshold">-threshold</a> will by default 798gray-scale the image before thresholding, if no <a href="#channel" 799>-channel</a> setting has been defined. </p> 800 801<p>Also some operators such as <a href="#blur">-blur</a>, <a 802href="#gaussian-blur">-gaussian-blur</a>, will modify their handling of the 803color channels if the '<kbd>alpha</kbd>' channel is also enabled by <a 804href="#channel" >-channel</a>. Generally this done to ensure that 805fully-transparent colors are treated as being fully-transparent, and thus any 806underlying 'hidden' color has no effect on the final results. Typically 807resulting in 'halo' effects. </p> 808 809<p>As a alpha channel is optional within images some operators will read the 810color channels of an image as a greyscale alpha mask, when the image has no 811alpha channel present, but the <a href="#channel" >-channel</a> setting tells 812the operator to apply the alpha channel. The <a href="#clut">-clut</a> 813operator is a good example of this. </p> 814 815 816<div style="margin: auto;"> 817 <h4><a name="clamp" id="clamp"></a>-clamp</h4> 818</div> 819 820<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> 821 822<div style="margin: auto;"> 823 <h4><a name="charcoal" id="charcoal"></a>-charcoal <em class="arg">factor</em></h4> 824</div> 825 826<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> 827 828<div style="margin: auto;"> 829 <h4><a name="chop" id="chop"></a>-chop <em class="arg">geometry</em></h4> 830</div> 831 832<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> 833 834<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> 835 836<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> 837 838<div style="margin: auto;"> 839 <h4><a name="clip" id="clip"></a>-clip</h4> 840</div> 841 842<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> 843 844<p>If a clipping path is present, it is applied to subsequent operations.</p> 845 846<p>For example, in the command</p> 847 848<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -clip -negate cockatoo.tif negated.tif</span></p> 849<p>only the pixels within the clipping path are negated.</p> 850 851<p>The <a href="#clip">-clip</a> feature requires the XML library. If the XML library is not present, the option is ignored.</p> 852 853<div style="margin: auto;"> 854 <h4><a name="clip-mask" id="clip-mask"></a>-clip-mask</h4> 855</div> 856 857<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> 858 859<div style="margin: auto;"> 860 <h4><a name="clip-path" id="clip-path"></a>-clip-path <em class="arg">id</em></h4> 861</div> 862 863<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> 864 865<div style="margin: auto;"> 866 <h4><a name="clone" id="clone"></a>-clone <em class="arg">index(s)</em></h4> 867</div> 868 869<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> 870 871<p>Specify the image by its index in the sequence. The first image is index 8720. Negative indexes are relative to the end of the sequence; for example, −1 873represents the last image of the sequence. Specify a range of images with a 874dash (e.g. 0−4). Separate multiple indexes with commas but no spaces (e.g. 0,2,5). Use <a 875href="#clone">+clone</a> make a copy of the last image in the image 876sequence.</p> 877 878<div style="margin: auto;"> 879 <h4><a name="clut" id="clut"></a>-clut</h4> 880</div> 881 882<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 883corresponding channel in the second image as a <b>c</b>olor 884<b>l</b>ook<b>u</b>p <b>t</b>able.</td><td style='text-align:right;'></td></tr></table> 885 886<p>The second (LUT) image is ordinarily a gradient image containing the 887histogram mapping of how each channel should be modified. Typically it is a 888either a single row or column image of replacement color values. If larger 889than a single row or column, values are taken from a diagonal line from 890top-left to bottom-right corners.</p> 891 892<p>The lookup is further controlled by the <a 893href="#interpolate">-interpolate</a> setting, which is especially handy for an 894LUT which is not the full length needed by the ImageMagick installed Quality 895(Q) level. Good settings for this are the '<kbd>bilinear</kbd>' and 896'<kbd>bicubic</kbd>' interpolation settings, which give smooth color 897gradients, and the '<kbd>integer</kbd>' setting for a direct, unsmoothed 898lookup of color values. </p> 899 900<p>This operator is especially suited to replacing a grayscale image with a 901specific color gradient from the CLUT image. </p> 902 903<p>Only the channel values defined by the <a href="#channel">-channel</a> 904setting will have their values replaced. In particular, since the default <a 905href="#channel">-channel</a> setting is <kbd>RGB</kbd>, this means that 906transparency (alpha/matte channel) is not affected, unless the <a 907href="#channel">-channel</a> setting is modified. When the alpha channel is 908set, it is treated by the <a href="#clut" >-clut</a> operator in the same way 909as the other channels, implying that alpha/matte values are replaced using the 910alpha/matte values of the original image. </p> 911 912<p>If either the image being modified, or the lookup image, conatins no 913transparency (i.e. <a href="#alpha" >-alpha</a> is turned 'off') but the <a 914href="#channel">-channel</a> setting includes alpha replacement, then it is 915assumed that image represents a gray-scale graident which will be used for the 916replacement alpha values. That is you can use a gray-scale CLUT image to 917adjust a existing images alpha channel, or you can color a gray-scale image 918using colors form CLUT containing the desired colors, including transparency. 919</p> 920 921<p>See also <a href="#hald-clut" >-hald-clut</a> which replaces colors according 922the lookup of the full color RGB value from a 2D representation of a 3D color 923cube. </p> 924 925 926<div style="margin: auto;"> 927 <h4><a name="coalesce" id="coalesce"></a>-coalesce</h4> 928</div> 929 930<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> 931 932<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 easilly viewed and processed than the highly optimized GIF overlay images. </p> 933 934<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> 935 936 937<div style="margin: auto;"> 938 <h4><a name="colorize" id="colorize"></a>-colorize <em class="arg">value</em></h4> 939</div> 940 941<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> 942 943<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> 944 945<div style="margin: auto;"> 946 <h4><a name="colormap" id="colormap"></a>-colormap <em class="arg">type</em></h4> 947</div> 948 949<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> 950 951<p>The <em class="arg">type</em> can be <kbd>shared</kbd> or <kbd>private</kbd>.</p> 952 953<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> 954 955<div style="margin: auto;"> 956 <h4><a name="colors" id="colors"></a>-colors <em class="arg">value</em></h4> 957</div> 958 959<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> 960 961<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> 962 963<div style="margin: auto;"> 964 <h4><a name="colorspace" id="colorspace"></a>-colorspace <em class="arg">value</em></h4> 965</div> 966 967<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> 968 969<p>Choices are:</p> 970 971<pre class="text"> 972 CMY 973 CMYK 974 Gray 975 HSB 976 HSL 977 HWB 978 Lab 979 Log 980 OHTA 981 Rec601Luma 982 Rec601YCbCr 983 Rec709Luma 984 Rec709YCbCr 985 RGB 986 sRGB 987 Transparent 988 XYZ 989 YCbCr 990 YCC 991 YIQ 992 YPbPr 993 YUV 994</pre> 995 996<p>To print a complete list of colorspaces, use <a href="#list">-list colorspace</a>.</p> 997 998<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> 999 1000<table class="doc"> 1001 <caption>Conversion Of RGB To Other Color Spaces</caption> 1002 <tr><th align="left" valign="middle">CMY</th></tr> 1003 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>−R</td></tr> 1004 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>−G</td></tr> 1005 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>−B</td></tr> 1006 <tr><th align="left" valign="middle">CMYK — starts with CMY from above</th></tr> 1007 <tr><td align="left" valign="middle">K=min(C,Y,M)</td></tr> 1008 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>*(C−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 1009 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>*(M−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 1010 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>*(Y−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 1011 1012 <tr><th align="left" valign="middle">Gray</th></tr> 1013 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr> 1014 1015 <tr><th align="left" valign="middle">HSB — Hue, Saturation, Brightness; like a cone peak downward</th></tr> 1016 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr> 1017 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr> 1018 <tr><td align="left" valign="middle">B=distance along axis from bottom upward; B=max(R,G,B); <em>intensity-like</em></td></tr> 1019 1020 <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> 1021 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr> 1022 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr> 1023 <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> 1024 1025 <tr><th align="left" valign="middle">HWB — Hue, Whiteness, Blackness</th></tr> 1026 <tr><td align="left" valign="middle">Hue (complicated equation)</td></tr> 1027 <tr><td align="left" valign="middle">Whiteness (complicated equation)</td></tr> 1028 <tr><td align="left" valign="middle">Blackness (complicated equation)</td></tr> 1029 1030 <tr><th align="left" valign="middle">LAB</th></tr> 1031 <tr><td align="left" valign="middle">L (complicated equation relating X,Y,Z)</td></tr> 1032 <tr><td align="left" valign="middle">A (complicated equation relating X,Y,Z)</td></tr> 1033 <tr><td align="left" valign="middle">B (complicated equation relating X,Y,Z)</td></tr> 1034 1035 <tr><th align="left" valign="middle">LOG</th></tr> 1036 <tr><td align="left" valign="middle">I1 (complicated equation involving logarithm of R)</td></tr> 1037 <tr><td align="left" valign="middle">I2 (complicated equation involving logarithm of G)</td></tr> 1038 <tr><td align="left" valign="middle">I3 (complicated equation involving logarithm of B)</td></tr> 1039 1040 <tr><th align="left" valign="middle">OHTA — approximates principal components transformation</th></tr> 1041 <tr><td align="left" valign="middle">I1=0.33333*R+0.33334*G+0.33333*B; <em>intensity-like</em></td></tr> 1042 <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> 1043 <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> 1044 1045 <tr><th align="left" valign="middle">Rec601Luma</th></tr> 1046 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr> 1047 1048 <tr><th align="left" valign="middle">Rec601YCbCr</th></tr> 1049 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1050 <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> 1051 <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> 1052 1053 <tr><th align="left" valign="middle">Rec709Luma</th></tr> 1054 <tr><td align="left" valign="middle">Gray=0.21260*R+0.71520*G+0.07220*B</td></tr> 1055 1056 <tr><th align="left" valign="middle">Rec709YCbCr</th></tr> 1057 <tr><td align="left" valign="middle">Y=0.212600*R+0.715200*G+0.072200*B; <em>intensity-like</em></td></tr> 1058 <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> 1059 <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> 1060 1061 <tr><th align="left" valign="middle">sRGB</th></tr> 1062 <tr><td align="left" valign="middle">if Rs ≤ .03928 then Rs=R/12.92 else Rs=((R+.055)/1.055)^2.4</td></tr> 1063 <tr><td align="left" valign="middle">if Gs ≤ .03928 then Gs=B/12.92 else Gs=((G+.055)/1.055)^2.4</td></tr> 1064 <tr><td align="left" valign="middle">if Bs ≤ .03928 then Bs=B/12.92 else Bs=((B+.055)/1.055)^2.4</td></tr> 1065 1066 <tr><th align="left" valign="middle">XYZ</th></tr> 1067 <tr><td align="left" valign="middle">X=0.4124240*R+0.3575790*G+0.1804640*B</td></tr> 1068 <tr><td align="left" valign="middle">Y=0.2126560*R+0.7151580*G+0.0721856*B</td></tr> 1069 <tr><td align="left" valign="middle">Z=0.0193324*R+0.1191930*G+0.9504440*B</td></tr> 1070 1071 <tr><th align="left" valign="middle">YCC</th></tr> 1072 <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> 1073 <tr><td align="left" valign="middle">C1=(−0.29900*R−0.58700*G+0.88600*B) (with complicated scaling)</td></tr> 1074 <tr><td align="left" valign="middle">C2=(0.70100*R−0.58700*G−0.11400*B) (with complicated scaling)</td></tr> 1075 1076 <tr><th align="left" valign="middle">YCbCr</th></tr> 1077 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1078 <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> 1079 <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> 1080 1081 <tr><th align="left" valign="middle">YIQ</th></tr> 1082 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr> 1083 <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> 1084 <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> 1085 1086 <tr><th align="left" valign="middle">YPbPr</th></tr> 1087 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1088 <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> 1089 <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> 1090 1091 <tr><th align="left" valign="middle">YUV</th></tr> 1092 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr> 1093 <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> 1094 <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> 1095</table> 1096 1097<div style="margin: auto;"> 1098 <h4><a name="combine" id="combine"></a>-combine</h4> 1099</div> 1100 1101<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> 1102 1103<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> 1104 1105<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. 1106</p> 1107 1108<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 -combine imagecopy.png</span></p> 1109<div style="margin: auto;"> 1110 <h4><a name="comment" id="comment"></a>-comment <em class="arg">string</em></h4> 1111</div> 1112 1113<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> 1114 1115<p>This option places comments in a non-pixel portion of the image file. For a comment to be visibly written on the image itself, use the <a href="#annotate">-annotate</a> or <a href="#draw">-draw</a> options.</p> 1116 1117<p>Use this option to assign a specific comment to the image, when writing to an image format that supports comments. You can include the image filename, type, width, height, or other image attribute by embedding special format characters listed under the <a href="#format">-format</a> option. The comment is not drawn on the image, but is embedded in the image datastream via "Comment" tag or similar mechanism. </p> 1118 1119<p>For example,</p> 1120 1121<p class="crtsnip"> 1122 -comment "%m:%f %wx%h" 1123</p> 1124 1125<p>produces an image comment 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> 1126 1127<p>If the first character of <em class="arg">string</em> is <em class="arg">@</em>, the image comment is read from a file titled by the remaining characters in the string. Comments in a file are literal; no embedded formatting characters are recognized.</p> 1128 1129<div style="margin: auto;"> 1130 <h4><a name="compose" id="compose"></a>-compose <em class="arg">operator</em></h4> 1131</div> 1132 1133<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> 1134 1135<p>The description of composition uses abstract terminology in order to allow 1136the description to be more precise, while avoiding constant values which are 1137specific to a particular build configuration. Each image pixel is represented 1138by red, green, and blue levels (which are equal for a gray pixel). The 1139build-dependent value <em class="QR">QuantumRange</em> is the maximum integral 1140value which may be stored, per pixel, in the red, green, or blue channels of 1141the image. Each image pixel may also optionally (if the image matte channel is 1142enabled) have an associated level of opacity, ranging from <em>opaque</em> to 1143<em>transparent</em>, which may be used to determine the influence of the pixel 1144color when compositing the pixel with another image pixel. If the image matte 1145channel is disabled, then all pixels in the image are treated as opaque. The 1146color of an opaque pixel is fully visible while the color of a transparent 1147pixel color is entirely absent (pixel color is ignored).</p> 1148 1149<p>By definition, raster images have a rectangular shape. All image rows are of 1150equal length, as are all image columns. By treating the alpha channel as a 1151visual "mask" the rectangular image may be given a "shape" by treating the 1152alpha channel as a cookie-cutter for the image. This is done by setting the 1153pixels within the shape to be opaque, with pixels outside the shape set as 1154transparent. Pixels on the boundary of the shape may be between opaque and 1155transparent in order to provide antialiasing (visually smooth edges). The 1156description of the composition operators use this concept of image "shape" in 1157order to make the description of the operators easier to understand. While it 1158is convenient to describe the operators in terms of "shapes" they are by no 1159means limited to mask-style operations since they are based on continuous 1160floating-point mathematics rather than simple boolean operations.</p> 1161 1162<p>The following alpha blending (Duff-Porter) compose methods are available:</p> 1163 1164<table class="doc"> 1165 <tbody> 1166 <tr valign="top"> 1167 <th align="left" style="width: 8%">Method</th> 1168 <th align="left">Description</th> 1169 </tr> 1170 1171 <tr valign="top"> 1172 <td valign="top">clear</td> 1173 <td valign="top">Both the color and the alpha of the destination are 1174 cleared. Neither the source nor the destination are used (except for 1175 destinations size and other meta-data which is always preserved.</td> 1176 </tr> 1177 1178 <tr valign="top"> 1179 <td valign="top">src</td> 1180 <td valign="top">The source is copied to the destination. The destination 1181 is not used as input, though it is cleared.</td> 1182 </tr> 1183 1184 <tr valign="top"> 1185 <td valign="top">dst</td> 1186 <td valign="top">The destination is left untouched. The source image is 1187 completely ignored.</td> 1188 </tr> 1189 1190 <tr valign="top"> 1191 <td valign="top">src-over</td> 1192 <td valign="top">The source is composited over the destination. this is 1193 the default alpha blending compose method, when neither the compose 1194 setting is set, nor is set in the image meta-data.</td> 1195 </tr> 1196 1197 <tr valign="top"> 1198 <td valign="top">dst-over</td> 1199 <td valign="top">The destination is composited over the source and the 1200 result replaces the destination.</td> 1201 </tr> 1202 1203 <tr valign="top"> 1204 <td valign="top">src-in</td> 1205 <td valign="top">The part of the source lying inside of the destination 1206 replaces the destination.</td> 1207 </tr> 1208 1209 <tr valign="top"> 1210 <td valign="top">dst-in</td> 1211 <td valign="top">The part of the destination lying inside of the source 1212 replaces the destination. Areas not overlaid are cleared.</td> 1213 </tr> 1214 1215 <tr valign="top"> 1216 <td valign="top">src-out</td> 1217 <td valign="top">The part of the source lying outside of the destination 1218 replaces the destination.</td> 1219 </tr> 1220 1221 <tr valign="top"> 1222 <td valign="top">dst-out</td> 1223 <td valign="top">The part of the destination lying outside of the source 1224 replaces the destination.</td> 1225 </tr> 1226 1227 <tr valign="top"> 1228 <td valign="top">src-atop</td> 1229 <td valign="top">The part of the source lying inside of the destination is 1230 composited onto the destination.</td> 1231 </tr> 1232 1233 <tr valign="top"> 1234 <td valign="top">dst-atop</td> 1235 <td valign="top">The part of the destination lying inside of the source is 1236 composited over the source and replaces the destination. Areas not 1237 overlaid are cleared. </td> 1238 </tr> 1239 1240 <tr valign="top"> 1241 <td valign="top">xor</td> 1242 <td valign="top">The part of the source that lies outside of the 1243 destination is combined with the part of the destination that lies 1244 outside of the source. Source or Destination, but not both. </td> 1245 </tr> 1246 1247 </tbody> 1248</table> 1249 1250<p>Any of the 'Src-*' methods can also be specified without the 'Src-' part. 1251For example the defaul compose method can be specified as just 'Over'.</p> 1252 1253 1254<p>The following mathemathical composition methods are also available. </p> 1255 1256<p>Typically these use the default 'Over' alpha blending when transparencies 1257are also involved, except for 'Plus', 'Minus', 'Add', and 'Subtract', which 1258also composes the alpha channel using the same process as the color channels. 1259This allows them to be used for special image masking techniques. </p> 1260 1261<table class="doc"> 1262 <tbody> 1263 <tr valign="top"> 1264 <th align="left" style="width: 8%">Method</th> 1265 <th align="left">Description</th> 1266 </tr> 1267 1268 <tr valign="top"> 1269 <td valign="top">multiply</td> 1270 <td valign="top">The source is multiplied by the destination and replaces the destination. The resultant color is always at least as dark as either of the two constituent colors. Multiplying any color with black produces black. Multiplying any color with white leaves the original color unchanged.</td> 1271 </tr> 1272 1273 <tr valign="top"> 1274 <td valign="top">screen</td> 1275 <td valign="top">The source and destination are complemented and then multiplied and then replace the destination. The resultant color is always at least as light as either of the two constituent colors. Screening any color with white produces white. Screening any color with black leaves the original color unchanged.</td> 1276 </tr> 1277 1278 <tr valign="top"> 1279 <td valign="top">plus</td> 1280 <td valign="top">The source is added to the destination and replaces the 1281 destination. This operator is useful for averaging or a controled 1282 merger of two images, rather than a direct overlay.</td> 1283 </tr> 1284 1285 <tr valign="top"> 1286 <td valign="top">add</td> 1287 <td valign="top">As per 'plus' but transparency data is treated as matte 1288 values. As such any transparent areas in either image remain 1289 transparent. </td> 1290 </tr> 1291 1292 <tr valign="top"> 1293 <td valign="top">minus</td> 1294 <td valign="top">Subtract the colors in the source image from the 1295 destination image. When transparency is involved, opaque areas is 1296 subtracted from any destination opaque areas. </td> 1297 </tr> 1298 1299 <tr valign="top"> 1300 <td valign="top">subtract</td> 1301 <td valign="top">Subtract the colors in the source image from the 1302 destination image. When transparency is involved transparent areas are 1303 subtracted, so only the opaque areas in the source remain opaque in 1304 the destination image. </td> 1305 </tr> 1306 1307 <tr valign="top"> 1308 <td valign="top">difference</td> 1309 <td valign="top">Subtracts the darker of the two constituent colors from 1310 the lighter. Painting with white inverts the destination color. 1311 Painting with black produces no change.</td> 1312 </tr> 1313 1314 <tr valign="top"> 1315 <td valign="top">exclusion</td> 1316 <td valign="top">Produces an effect similar to that of 'difference', but 1317 appears as lower contrast. Painting with white inverts the 1318 destination color. Painting with black produces no change.</td> 1319 </tr> 1320 1321 <tr valign="top"> 1322 <td valign="top">darken</td> 1323 <td valign="top">Selects the darker of the destination and source colors. 1324 The destination is replaced with the source when the source is darker, 1325 otherwise it is left unchanged.</td> 1326 </tr> 1327 1328 <tr valign="top"> 1329 <td valign="top">lighten</td> 1330 <td valign="top">Selects the lighter of the destination and source colors. 1331 The destination is replaced with the source when the source is 1332 lighter, otherwise it is left unchanged. </td> 1333 </tr> 1334 1335 <tr valign="top"> 1336 <td valign="top">linear-dodge</td> 1337 <td valign="top">This is equivelent to 'Plus' in that the color channels 1338 are simply added, however it does not 'Plus' the alpha channel, but 1339 uses the normal 'Over' alpha blending, which transparencies are 1340 involved. Produces a sort of additive multiply-like result. Added 1341 ImageMagick version 6.5.4-3. </td> 1342 </tr> 1343 1344 <tr valign="top"> 1345 <td valign="top">linear-burn</td> 1346 <td valign="top">As 'Linear-Dodge', but also subtract one from the result. 1347 Sort of a additive 'Screen' of the images. Added ImageMagick version 1348 6.5.4-3. </td> 1349 </tr> 1350 1351 <tr valign="top"> 1352 <td valign="top">color-dodge</td> 1353 <td valign="top">Brightens the destination color to reflect the source 1354 color. Painting with black produces no change.</td> 1355 </tr> 1356 1357 <tr valign="top"> 1358 <td valign="top">color-burn</td> 1359 <td valign="top">Darkens the destination color to reflect the source 1360 color. Painting with white produces no change. Fixed in ImageMagick 1361 version 6.5.4-3. </td> 1362 </tr> 1363 1364 <tr valign="top"> 1365 <td valign="top">overlay</td> 1366 <td valign="top">Multiplies or screens the colors, dependent on the 1367 destination color. Source colors overlay the destination whilst 1368 preserving its highlights and shadows. The destination color is not 1369 replaced, but is mixed with the source color to reflect the lightness 1370 or darkness of the destination.</td> 1371 </tr> 1372 1373 <tr valign="top"> 1374 <td valign="top">hard-light</td> 1375 <td valign="top">Multiplies or screens the colors, dependent on the source 1376 color value. If the source color is lighter than 0.5, the destination 1377 is lightened as if it were screened. If the source color is darker 1378 than 0.5, the destination is darkened, as if it were multiplied. The 1379 degree of lightening or darkening is proportional to the difference 1380 between the source color and 0.5. If it is equal to 0.5 the 1381 destination is unchanged. Painting with pure black or white produces 1382 black or white.</td> 1383 </tr> 1384 1385 1386 <tr valign="top"> 1387 <td valign="top">linear-light</td> 1388 <td valign="top">Like 'Hard-Light' but using linear-dodge and linear-burn 1389 instead. Increases contrast slightly with an impact on the 1390 foreground's tonal values.</td> 1391 </tr> 1392 1393 <tr valign="top"> 1394 <td valign="top">soft-light</td> 1395 <td valign="top">Darkens or lightens the colors, dependent on the source 1396 color value. If the source color is lighter than 0.5, the destination 1397 is lightened. If the source color is darker than 0.5, the destination 1398 is darkened, as if it were burned in. The degree of darkening or 1399 lightening is proportional to the difference between the source color 1400 and 0.5. If it is equal to 0.5, the destination is unchanged. Painting 1401 with pure black or white produces a distinctly darker or lighter area, 1402 but does not result in pure black or white. Fixed in ImageMagick 1403 version 6.5.4-3. </td> 1404 </tr> 1405 1406 <tr valign="top"> 1407 <td valign="top">pegtop-light</td> 1408 <td valign="top">Almost equivelent to 'Soft-Light', but using a 1409 continuious mathematical formula rather than two conditionally 1410 selected formulae. Added ImageMagick version 6.5.4-3. </td> 1411 </tr> 1412 1413 <tr valign="top"> 1414 <td valign="top">vivid-light</td> 1415 <td valign="top">A modified 'Linear-Light' designed to preserve very stong 1416 primary and secondary colors in the image. Added ImageMagick version 1417 6.5.4-3. </td> 1418 </tr> 1419 1420 <tr valign="top"> 1421 <td valign="top">pin-light</td> 1422 <td valign="top">Similar to 'Hard-Light', but using sharp linear shadings, 1423 to similate the effects of a strong 'pinhole' light source. Added 1424 ImageMagick version 6.5.4-3. </td> 1425 </tr> 1426 1427 </tbody> 1428</table> 1429 1430 1431<p>Also included are these special purpose compose methods:</p> 1432 1433<table class="doc"> 1434 <tbody> 1435 <tr valign="top"> 1436 <th align="left" style="width: 8%">Method</th> 1437 <th align="left">Description</th> 1438 </tr> 1439 1440 <tr valign="top"> 1441 <td valign="top">copy-*</td> 1442 <td valign="top">Copy the specified channel (Red, Green, Blue, Cyan, 1443 Magenta, Yellow, Black, or Opacity) in the source image to the 1444 same channel in the destination image. If the channel specified 1445 does not exist in the source image, (which can only happen for methods, 1446 '<kbd>copy-opacity</kbd>' or '<kbd>copy-black</kbd>') then it is 1447 assumed that the source image is a special grayscale channel image 1448 of the values to be copied. </td> 1449 </tr> 1450 1451 <tr valign="top"> 1452 <td valign="top">change-mask</td> 1453 <td valign="top">Replace any destination pixel that is the similar to the source images pixel (as defined by the current <a href="#fuzz">-fuzz</a> factor), with transparency. </td> 1454 </tr> 1455 </tbody> 1456</table> 1457 1458<p>On top of these composed methods are a few special ones that not only require 1459the two images that are being merged or overlaid, but have some extra numerical 1460arguments, which are tabled below. </p> 1461 1462<p>In the "<code>composite</code>" command these composition methods are 1463selected using special options with the arguments needed. They are usually, 1464but not always, the same name as the composte 'method' they use, and replaces 1465the normal use of the <a href="#compose" >-compose</a> setting in the 1466"<code>composite</code>" command. For example... </p> 1467 1468<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>composite ... -blend 50x50 ...</span></p> 1469<p>As of IM v6.5.3-4 the "<code>convert</code>" command can now also supply 1470these extra arguments to its <a href="#composite" >-composite</a> operator, 1471using the special <a href="#set">-set</a> attribute of '<kbd class="arg">option:compose:args</kbd>'. This means you can now make use of 1472these special argumented <a href="#compose" >-compose</a> methods, those the 1473argument and the method both need to be set separatally. For example... </p> 1474 1475<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert ... -compose blend -set option:compose:args 50x50 -composite ...</span></p> 1476<p>The following is a table of these special 'argumented' compose methods, 1477with a brief summary of what they do. For more details see the equivalent 1478"composite" command option name. </p> 1479 1480<table class="doc"> 1481 <tbody> 1482 <tr valign="top"> 1483 <th align="left" style="width: 8%">Method</th> 1484 <th align="left">Description</th> 1485 </tr> 1486 1487 <tr valign="top"> 1488 <td valign="top">dissolve</td> 1489 <td valign="top">Arguments: 1490 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>] 1491 <br>Equivalent to "<code>composite</code>" <a href="#dissolve">-dissolve</a> 1492 <br>Dissolve the 'source' image by the percentage given before overlaying 1493 'over' the 'destination' image. If <em class="arg">src_percent</em> is 1494 greater than 100, it starts dissolving the main image so it will 1495 become transparent at a value of '<kbd class="arg">200</kbd>'. If 1496 both percentages are given, each image are dissolved to the 1497 percentages given. 1498 </td> 1499 </tr> 1500 1501 <tr valign="top"> 1502 <td valign="top">blend</td> 1503 <td valign="top">Arguments: 1504 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>] 1505 <br>Equivalent to "<code>composite</code>" <a href="#blend">-blend</a> 1506 <br>Average the images together ('plus') according to the percentages 1507 given and each pixels transparency. If only a single percentage value 1508 is given it sets the weight of the composite or 'source' image, while 1509 the background image is weighted by the exact opposite amount. That is 1510 a <kbd>-blend 30</kbd> merges 30% of the 'source' image with 70% of 1511 the 'destination' image. Thus it is equivalent to <kbd>-blend 1512 30x70</kbd>. 1513 </td> 1514 </tr> 1515 1516 <tr valign="top"> 1517 <td valign="top">mathematics</td> 1518 <td valign="top">Arguments: <em class="arg">A, B, C, D</em> 1519 <br>Not available in "<code>composite</code>" at this time. 1520 <br>Merge the source and destination images according to the formula 1521 <br> <code>A*Sc*Dc + B*Sc + C*Dc + D</code> 1522 <br>Can be used to generate a custom composition method that would 1523 otherwise need to be implemented using the slow <a href="#fx">-fx</a> 1524 DIY image operator. Added to ImageMagick version 6.5.4-3. 1525 </td> 1526 </tr> 1527 1528 <tr valign="top"> 1529 <td valign="top">modulate</td> 1530 <td valign="top">Arguments: 1531 <em class="arg">brightness</em>[x<em class="arg">saturation</em>] 1532 <br>Equivalent to "<code>composite</code>" <a href="#watermark">-watermark</a> 1533 <br>Take a grayscale image (with alpha mask) and modify the destination 1534 image's brightness according to watermark image's grayscale value and 1535 the <em class="arg">brightness</em> percentage. The destinations 1536 color saturation attribute is just direct modified by the <em 1537 class="arg">saturation</em> percentage, which defaults to 100 percent 1538 (no color change). 1539 1540 </td> 1541 </tr> 1542 1543 <tr valign="top"> 1544 <td valign="top">displace</td> 1545 <td valign="top">Arguments: 1546 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em>][!][%] 1547 <br>Equivalent to "<code>composite</code>" <a href="#displace">-displace</a> 1548 <br>With this option, the 'overlay' image, and optionally the 'mask' 1549 image, is used as a relative displacement map, which is used to 1550 displace the lookup of what part of the destination image is seen at 1551 each point of the overlaid area. Much like the displacement map is a 1552 'lens' that distorts the original 'background' image behind it. 1553 <br><br> 1554 The X-scale is modilated by the 'red' channel of the overlay image 1555 while the Y-scale is modulated by the green channel, (the mask image 1556 if given is rolled into green channel of the overlay image. This 1557 separation allows you to modulate the X and Y lookup displacement 1558 separatally allowing you to di 2 dimentional displacements, rather 1559 than 1 dimentional verctored displacements (using grayscale image). 1560 <br><br> 1561 If the overlay image contains transparency this is used as a mask 1562 of the resulting image to remove 'invalid' pixels. 1563 <br><br> 1564 The '%' flag makes the displacement scale relative to the size of the 1565 overlay image (100% = half width/height of image). Using '!' switches 1566 percentage arguments to refer to the destination image size instead. 1567 <br><br> 1568 Special flags were added Added to ImageMagick version 6.5.3-5. 1569 </td> 1570 </tr> 1571 1572 <tr valign="top"> 1573 <td valign="top">distort</td> 1574 <td valign="top">Arguments: 1575 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em 1576 >[+<em class="arg">X-center</em>+<em class="arg">Y-center</em>]][!][%] 1577 <br>Not available in "<code>composite</code>" at this time. 1578 <br>Exactly as per 'Displace' (above), but using absolute coordinates, 1579 relative to the center of the overlay (or that given). Basically 1580 allows you to generate absolute distortion maps where 'black' will 1581 look up the left/top edge, and 'white' looks up the bottom/right 1582 edge of the destination image, according to the scale given. 1583 <br><br> 1584 The '!' flag not only switches percentage scaling, to use the 1585 destination image, but also the image the center offset of the lookup. 1586 This means the overlay can lookup a completely different region of the 1587 destination image. 1588 <br><br> 1589 Added to ImageMagick version 6.5.3-5. 1590 </td> 1591 </tr> 1592 1593 <tr valign="top"> 1594 <td valign="top">blur</td> 1595 <td valign="top">Arguments: 1596 <em class="arg">Width</em>[x<em class="arg">Height</em 1597 >[+<em class="arg">Angle</em>]] 1598 <br>Equivalent to "<code>composite</code>" 1599 <a href="#blur-composite">-blur</a> 1600 <br>A Variable Blur Mapping Composition method, where each pixel in the 1601 overlaid region is replaced with an Elliptical Weighted Average (EWA), 1602 with an ellipse (typically a circle) of the given sigma size, scaled 1603 according to overlay (source image) grayscale mapping. 1604 <br><br> 1605 As per 'Displace' and 'Distort', the red channel will modulate the 1606 width of the ellipse, while the green channel will modulate the height 1607 of the ellipse. However at this time the ellipse angle is not 1608 modulated though this may be a future posibility (perhaps with a 1609 special flag to enable use of blur channel for this purpose). 1610 <br><br> 1611 Added to ImageMagick version 6.5.4-0. 1612 </td> 1613 </tr> 1614 1615 </tbody> 1616</table> 1617 1618<p>To print a complete list of all the available compose operators, use <a href="#list">-list compose</a>.</p> 1619 1620 1621<div style="margin: auto;"> 1622 <h4><a name="composite" id="composite"></a>-composite</h4> 1623</div> 1624 1625<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Perform alpha composition on the current image sequence.</td><td style='text-align:right;'></td></tr></table> 1626 1627<p>Take the first image 'destination' and overlay the second 'source' image 1628according to the current <a href="#compose">-compose</a> setting. The location 1629of the 'source' or 'overlay' image is controlled according to <a 1630href="#geometry" >-geometry</a>, and <a href="#geometry" >-geometry</a> 1631settings. </p> 1632 1633<p>If a third image is given this is treated as a gray-scale 'mask' image 1634relative to the first 'destination' image. This mask will limit what parts of 1635the destination can be modified by the image composition. However for the 1636'<kbd>displace</kbd>' compose method, the mask is used to provide a separate 1637Y-displacement image instead. </p> 1638 1639<p>If a <a href="#compose">-compose</a> method requires extra numerical 1640arguments or flags these can be provided by setting the <a 1641href="#set">-set</a> '<kbd class="arg">option:compose:args</kbd>' 1642appropriatally for the compose method. </p> 1643 1644<p>Some <a href="#compose">-compose</a> methods can modify the 'destination' 1645image outside the overlay area. You can disable this by setting the special <a 1646href="#set">-set</a> '<kbd class="arg">option:compose:outside-overlay</kbd>' 1647to '<kbd>false</kbd>'. </p> 1648 1649 1650<div style="margin: auto;"> 1651 <h4><a name="compress" id="compress"></a>-compress <em class="arg">type</em></h4> 1652</div> 1653 1654<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> 1655 1656<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> 1657 1658<p>To print a complete list of compression types, use <a href="#list">-list compress</a>.</p> 1659 1660<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> 1661 1662<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> 1663 1664<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> 1665 1666<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> 1667 1668<div style="margin: auto;"> 1669 <h4><a name="contrast" id="contrast"></a>-contrast</h4> 1670</div> 1671 1672<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> 1673 1674<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> 1675 1676<p>For a more pronounced effect you can repeat the option:</p> 1677 1678<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -contrast -contrast rose_c2.png</span></p> 1679<div style="margin: auto;"> 1680 <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> 1681</div> 1682 1683<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> 1684 1685<p>While performing the stretch, black-out at most <em 1686class="arg" >black-point</em> pixels and white-out at most <em 1687class="arg" >white-point</em> pixels. Or, if percent is used, black-out at most 1688<em class="arg" >black-point %</em> pixels and white-out at most <em 1689class="arg" >white-point %</em> pixels.</p> 1690 1691<p>Prior to ImageMagick 6.4.7-0, <a href="#contrast-stretch" 1692>-contrast-stretch</a> will black-out at most <em class="arg" 1693>black-point</em> pixels and white-out at most <em class="arg" >total pixels 1694minus white-point</em> pixels. Or, if percent is used, black-out at most <em 1695class="arg">black-point %</em> pixels and white-out at most <em class="arg" 1696>100% minus white-point %</em> pixels.</p> 1697 1698<p>Note that <kbd>-contrast-stretch 0</kbd> will modify the image such that 1699the image's min and max values are stretched to 0 and <em class="QR" 1700>QuantumRange</em>, respectively, without any loss of data due to burn-out or 1701clipping at either end. This is not the same as <a href="#normalize" 1702>-normalize</a>, which is equivalent to <kbd>-contrast-stretch 2%x1%</kbd> (or 1703prior to ImageMagick 6.4.7-0, <kbd>-contrast-stretch 2%x99%</kbd>).</p> 1704 1705<p>Internally operator works by creating a histogram bin, and then uses that 1706bin to modify the image. As such some colors may be merged together when they 1707originally fell into the same 'bin'. </p> 1708 1709<p>All the channels are normalized in concert by the came amount so as to 1710preserve color integrity, when the default <a href="#channel" >+channel</a> 1711setting is in use. Specifing any other <a href="#channel" >-channel</a> 1712setting will normalize the RGB channels independently.</p> 1713 1714<p>See also <a href="#auto-level" >-auto-level</a> for a 'perfect' 1715normalization of mathematical images. </p> 1716 1717<p>This operator is under review for re-development. </p> 1718 1719 1720<div style="margin: auto;"> 1721 <h4><a name="convolve" id="convolve"></a>-convolve <em class="arg">kernel</em></h4> 1722</div> 1723 1724<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> 1725 1726<p>The <em class="arg">kernel</em> is a matrix specified as 1727a comma-separated list of integers (with no spaces), ordered left-to right, 1728starting with the top row. Presently, only odd-dimensioned kernels are 1729supported, and therefore the number of entries in the specified <em 1730class="arg">kernel</em> must be 3<sup>2</sup>=9, 5<sup>2</sup>=25, 17317<sup>2</sup>=49, etc. </p> 1732 1733<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 1734positive and negative results are relative to a user-specified bias value. 1735This is important for non-HDRI compilations of ImageMagick when dealing with 1736convolutions that contain negative as well as positive values. This is 1737especially the case with convolutions involving high pass filters or edge 1738detection. Without an output bias, the negative values is clipped at zero. 1739</p> 1740 1741<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 1742negative results without clipping to the color value range (0..QuantumRange). 1743See the discussion on HDRI implementations of ImageMagick on the page <a 1744href="/www/high-dynamic-range.html">High 1745Dynamic-Range Images</a>. For more about HDRI go the ImageMagick <a 1746href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this 1747<a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a> 1748entry. </p> 1749 1750 1751<div style="margin: auto;"> 1752 <h4><a name="crop" id="crop"></a>-crop <em class="arg">geometry</em></h4> 1753</div> 1754 1755<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> 1756 1757<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> 1758 1759<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> 1760 1761<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> 1762 1763<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> 1764 1765<p>By adding a exclamation character flag to the geometry argument, the 1766cropped images virtual canvas page size and offset is set as if the 1767geometry argument was a viewport or window. This means the canvas page size 1768is set to exactly the same size you specified, the image offset set 1769relative top left corner of the region cropped. </p> 1770 1771<p>If the cropped image 'missed' the actual image on its virtual canvas, a 1772special single pixel transparent 'missed' image is returned, and a 'crop 1773missed' warning given. </p> 1774 1775<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> 1776 1777<div style="margin: auto;"> 1778 <h4><a name="cycle" id="cycle"></a>-cycle <em class="arg">amount</em></h4> 1779</div> 1780 1781<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> 1782 1783<p><em class="arg">Amount</em> defines the number of positions each 1784colormap entry is shifted.</p> 1785 1786 1787<div style="margin: auto;"> 1788 <h4><a name="debug" id="debug"></a>-debug <em class="arg">events</em></h4> 1789</div> 1790 1791<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> 1792 1793<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> 1794 1795 1796<p>For example, to log cache and blob events, use.</p> 1797 1798<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -debug "Cache,Blob" rose: rose.png</span></p> 1799<p>The <kbd>User</kbd> domain is normally empty, but developers can log user events in their private copy of ImageMagick.</p> 1800 1801<p>To print the complete list of debug methods, use <a href="#list">-list debug</a>.</p> 1802 1803<p>Use the <a href="#log">-log</a> option to specify the format for debugging output.</p> 1804 1805<p>Use <a href="#debug">+debug</a> to turn off all logging.</p> 1806 1807<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> 1808 1809 1810<div style="margin: auto;"> 1811 <h4><a name="decipher" id="decipher"></a>-decipher <em class="arg">filename</em></h4> 1812</div> 1813 1814<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> 1815 1816<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p> 1817 1818<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p> 1819 1820 1821<div style="margin: auto;"> 1822 <h4><a name="deconstruct" id="deconstruct"></a>-deconstruct</h4> 1823</div> 1824 1825<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> 1826 1827<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> 1828 1829<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> 1830 1831<p>This option is actually equivalent to the <a href="#layers">-layers</a> method '<kbd>compare-any</kbd>'. </p> 1832 1833 1834<div style="margin: auto;"> 1835 <h4><a name="define" id="define"></a>-define <em class="arg">key</em>{<em class="arg">=value</em>}<em class="arg">...</em></h4> 1836</div> 1837 1838<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>add coder/decoder specific options.</td><td style='text-align:right;'></td></tr></table> 1839 1840<p>This option creates one or more definitions for coders and decoders to use while reading and writing image data. Definitions may be passed to coders and decoders to control options that are specific to certain image formats. If <em class="arg">value</em> is missing for a definition, an empty-valued definition of a flag is created with that name. This used to control on/off options. Use <a href="#define">+define key</a> to remove definitions previously created. Use <a href="#define">+define "*"</a> to remove all existing definitions.</p> 1841 1842<p>The following definitions may be created:</p> 1843 1844<ul> 1845<dt>dcm:display-range=reset</dt> 1846 <dd>Set the display range to the minimum and maximum pixel values for the DCM image format.</dd><br /> 1847<dt>dot:layout-engine=<em class="arg">value</em></dt> 1848 <dd>Set the specify the layout engine for the DOT image format (e.g. <kbd>neato</kbd>).</dd><br /> 1849<dt>jpeg:extent=<em class="arg">value</em></dt> 1850 <dd>Restrict the maximum JPEG file size, for example <kbd>-define jpeg:extent=400kb</kbd>.</dd><br /> 1851<dt>jpeg:size=<em class="arg">geometry</em></dt> 1852 <dd>Set the size hint of a JPEG image, for example, -define jpeg:size=128x128. It is most useful for increasing performance and reducing the memory requirements when reducing the size of a large JPEG image.</dd><br /> 1853<dt>jp2:rate=<em class="arg">value</em></dt> 1854 <dd>Specify the compression factor to use while writing JPEG-2000 files. The compression factor is the reciprocal of the compression ratio. The valid range is 0.0 to 1.0, with 1.0 indicating lossless compression. If defined, this value overrides the -quality setting. A quality setting of 75 results in a rate value of 0.06641.</dd><br /> 1855<dt>mng:need-cacheoff</dt> 1856 <dd>turn playback caching off for streaming MNG.</dd><br /> 1857<dt>png:bit-depth=<em class="arg">value</em></dt> 1858<dt>png:color-type=<em class="arg">value</em></dt> 1859 <dd>desired bit-depth and color-type for PNG output. You can force the PNG encoder to use a different bit-depth and color-type than it would have normally selected, but only if this does not cause any loss of image quality. Any attempt to reduce image quality is treated as an error and no PNG file is written. E.g., if you have a 1-bit black-and-white image, you can use these "defines" to cause it to be written as an 8-bit grayscale, indexed, or even a 64-bit RGBA. But if you have a 16-million color image, you cannot force it to be written as a grayscale or indexed PNG. If you wish to do this, you must use the appropriate <a href="#depth">-depth</a>, <a href="#colors">-colors</a>, or <a href="#type">-type</a> directives to reduce the image quality prior to using the PNG encoder. Note that in indexed PNG files, "bit-depth" refers to the number of bits per index, which can range from 1 to 8. In such files, the color samples always have 8-bit depth.</dd><br /> 1860<dt>ps:imagemask</dt> 1861 <dd>If the ps:imagemask flag is defined, the PS3 and EPS3 coders will create Postscript files that render bilevel images with the Postscript imagemask operator instead of the image operator.</dd><br /> 1862<dt>quantum:format=<em class="arg">type</em></dt> 1863 <dd>Set the type to <kbd>floating-point</kbd> to specify a single precision floating-point format for raw files (e.g. GRAY:).</dd> 1864</ul> 1865 1866<p>For example, to create a postscript file that will render only the black pixels of a bilevel image, use:</p> 1867 1868<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert bilevel.tif -define ps:imagemask eps3:stencil.ps</span></p> 1869<p>Set attributes of the image registry by prefixing the value with <kbd>registry:</kbd>. For example, to set a temporary path to put work files, use:</p> 1870 1871<p class="crtsnip"> 1872-define registry:temporary-path=/data/tmp 1873</p> 1874 1875<div style="margin: auto;"> 1876 <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> 1877</div> 1878 1879<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> 1880 1881<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> 1882 1883<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> 1884 1885 1886<div style="margin: auto;"> 1887 <h4><a name="delete" id="delete"></a>-delete <em class="arg">index</em></h4> 1888</div> 1889 1890<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> 1891 1892<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> 1893 1894 1895<div style="margin: auto;"> 1896 <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> 1897</div> 1898 1899<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> 1900 1901<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> 1902 1903<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> 1904 1905<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> 1906 1907<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> 1908 1909<div style="margin: auto;"> 1910 <h4><a name="depth" id="depth"></a>-depth <em class="arg">value</em></h4> 1911</div> 1912 1913<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> 1914 1915<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> 1916 1917<div style="margin: auto;"> 1918 <h4><a name="descend" id="descend"></a>-descend</h4> 1919</div> 1920 1921<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> 1922 1923<div style="margin: auto;"> 1924 <h4><a name="deskew" id="deskew"></a>-deskew <em class="arg">threshold</em></h4> 1925</div> 1926 1927<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> 1928 1929<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> 1930 1931<div style="margin: auto;"> 1932 <h4><a name="despeckle" id="despeckle"></a>-despeckle</h4> 1933</div> 1934 1935<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> 1936 1937<div style="margin: auto;"> 1938 <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> 1939</div> 1940 1941<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> 1942 1943<p>With this option, the 'overlay' image, and optionally the 'mask' image, 1944will be used as a displacement map, which is used to displace the lookup of 1945what part of the 'background' image is seen at each point of the overlaid 1946area. Much like the displacement map is a 'lens' that redirects light shining 1947through it so as to present a distorted view the original 'background' image 1948behind it. </p> 1949 1950<p>Any perfect grey areas of the displacement map produce a zero 1951displacement of the image. Black areas produce the given maximum negative 1952displacement of the lookup point, while white produce a maximum positive 1953displacement of the lookup. </p> 1954 1955<p>Note that it is the lookup of the 'background' that is displaced, not a 1956displacement of the image itself. As such an area of the displacement map 1957containing 'white' will have the lookup point 'shifted' by a positive amount, 1958and thus generating a copy of the destination image to the right/downward from 1959the correct position. That is the image will look like it may have been 1960'shifted' in a negative left/upward direction. Understanding this is a very 1961important in understanding how displacement maps work. </p> 1962 1963<p>The given arguments define the maximum amount of displacement in pixels 1964that a particular map can produce. If the displacement scale is large enough 1965it is also posible to lookup parts of the 'background' image that lie well 1966outside the bounds of the displacement map itself. That is you could very 1967easilly copy a section of the original image from outside the overlay area 1968into the overlay area. </p> 1969 1970<p>The '%' flag makes the displacement scale relative to the size of the 1971overlay image (100% = half width/height of image). Using '!' switches 1972percentage arguments to refer to the destination image size instead. 1973these flags were added as of IM v6.5.3-5.</p> 1974 1975<p>Normally a single grayscale displacement map is provided, which with the 1976given scaling values will determine a single direction (vector) in which 1977displacements can occur (positivally or negativally). However, if you also 1978specify a third image which is normally used as a <em class="arg">mask</em>, 1979then the <em class="arg">composite image</em> will be used for horizontal X 1980displacement, while the <em class="arg">mask image</em> is used for vertical Y 1981displacement. This allows you to define completely different displacement 1982values for the X and Y directions, and allowing you to lookup any point within 1983the <em class="arg">scale</em> bounds. In other words each pixel can lookup 1984any other nearby pixel, producing complex 2 dimentional displacements, rather 1985than a simple 1 dimentional vector displacements. </p> 1986 1987<p>Alternativally rather than suppling two separate images, as of IM v6.4.4-0, 1988you can use the 'red' channel of the overlay image to specify the horizontal 1989or X displacement, and the 'green' channel for the vertical or Y displacement. 1990</p> 1991 1992<p>As of IM v6.5.3-5 any alpha channel in the overlay image will be used as a 1993mask the transparency of the destination image. However areas outside the 1994overlaid areas will not be effected. </p> 1995 1996 1997<div style="margin: auto;"> 1998 <h4><a name="display" id="display"></a>-display <em class="arg">host:display[.screen]</em></h4> 1999</div> 2000 2001<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> 2002 2003<p>This option is used with convert for obtaining image or font from this X server. See <em class="arg">X(1)</em>.</p> 2004 2005<div style="margin: auto;"> 2006 <h4><a name="dispose" id="dispose"></a>-dispose <em class="arg">method</em></h4> 2007</div> 2008 2009<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> 2010 2011<p>The layer disposal method defines the way each the displayed image is to be 2012modified after the current 'frame' of an animation has finished being 2013displayed (after its 'delay' period), but before the next frame on an 2014animation is to be overlaid onto the display. </p> 2015 2016<p>Here are the valid methods:</p> 2017 2018<pre class="text"> 2019Undefined 0 No disposal specified (equivalent to '<kbd>none</kbd>'). 2020None 1 Do not dispose, just overlay next frame image. 2021Background 2 Clear the frame area with the background color. 2022Previous 3 Clear to the image prior to this frames overlay. 2023</pre> 2024 2025<p>You can also use the numbers given above, which is what the GIF format 2026uses internally to represent the above settings. </p> 2027 2028<p>To print a complete list of dispose methods, use <a href="#list">-list dipose</a>.</p> 2029 2030<p>Use <a href="#dispose" >+dispose</a>, turn off the setting and prevent 2031resetting the layer disposal methods of images being read in. </p> 2032 2033<p>Use <a href="#set">-set</a> '<kbd>dispose</kbd>' method to set the image 2034disposal method for images already in memory.</p> 2035 2036<div style="margin: auto;"> 2037 <h4><a name="dissimilarity-threshold" id="dissimilarity-threshold"></a>-dissimilarity-threshold <em class="arg">value</em></h4> 2038</div> 2039 2040<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> 2041 2042 2043<div style="margin: auto;"> 2044 <h4><a name="dissolve" id="dissolve"></a>-dissolve <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]</h4> 2045</div> 2046 2047<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> 2048 2049<p>The opacity of the composite image is multiplied by the given percent, then 2050it is composited 'over' the main image. If <em class="arg">src_percent</em> 2051is greater than 100, start dissolving the main image so it will become 2052transparent at a value of '<kbd class="arg">200</kbd>'. If both percentages 2053are given, each image are dissolved to the percentages given. </p> 2054 2055<p>Note that dissolve percentages do not add, two opaque images dissolved 2056'50,50', produce a 75% transparency. For a 50% + 50% blending of the two 2057images, you would need to use dissolve values of '50,100'. </p> 2058 2059<div style="margin: auto;"> 2060 <h4><a name="distort" id="distort"></a>-distort <em class="arg">method arguments</em></h4> 2061</div> 2062 2063<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> 2064 2065<p>The <em class="arg">arguments</em> is a single string containing a list 2066of floating point numbers separated by commas or spaces. The number of 2067and meaning of the floating point values depends on the distortion <em 2068class="arg">method</em> being used. </p> 2069 2070<p>Choose from these distortion types:</p> 2071 2072<table class="doc"> 2073 <tr valign="top"> 2074 <th align="left" style="width: 8%">Method</th> 2075 <th align="left">Description</th> 2076 </tr> 2077 2078 <tr valign="top"> 2079 <td valign="top"><kbd>ScaleRotateTranslate</kbd> 2080 <br/>or <kbd>SRT</kbd></td> 2081 <td valign="top"> 2082 Distort image by first scaling and rotating about a given 'center', 2083 before translating that 'center' to the new location, in that order. It 2084 is an alternative method of specifying a '<kbd>Affine</kbd>' type of 2085 distortion, but without shearing effects. It also provides a good way 2086 of rotating and displacing a smaller image for tiling onto a larger 2087 background (IE 2-dimensional animations). <br/> 2088 2089 The number of arguments determine the specific meaning of each 2090 argument for the scales, rotation, and translation operations. <br/> 2091 2092 <table style="margin-left:auto; margin-right:auto;"> 2093 <tr><td># </td><td>arguments meaning</td></tr> 2094 <tr><td>1:</td><td><em>Angle_of_Rotation</em></td></tr> 2095 <tr><td>2:</td><td><em>Scale Angle</em></td></tr> 2096 <tr><td>3:</td><td><em>ScaleX,ScaleY Angle</em></td></tr> 2097 <tr><td>4:</td><td><em>X,Y Scale Angle</em></td></tr> 2098 <tr><td>5:</td> 2099 <td><em>X,Y ScaleX,ScaleY Angle</em></td></tr> 2100 <tr><td>6:</td> 2101 <td><em>X,Y Scale Angle NewX,NewY</em></td></tr> 2102 <tr><td>7:</td> 2103 <td><em>X,Y ScaleX,ScaleY Angle 2104 NewX,NewY</em></td></tr> 2105 </table> 2106 2107 This is actually an alternative way of specifing a 2 dimensional linear 2108 '<kbd>Affine</kbd>' or '<kbd>AffineProjection</kbd>' distortion. </td> </tr> 2109 2110 <tr valign="top"> 2111 <td valign="top"><kbd>Affine</kbd></td> 2112 <td valign="top"> 2113 Distort the image linearly by moving a list of at least 3 or more sets 2114 of control points (as defined below). Idealy 3 sets or 12 floating 2115 point values are given allowing the image to be linearly scaled, 2116 rotated, sheared, and translated, according to those three points. See 2117 also the related '<kbd>AffineProjection</kbd>' and '<kbd>SRT</kbd>' 2118 distortions. <br/> 2119 2120 More than 3 sets given control point pairs (12 numbers) is least 2121 squares fitted to best match a lineary affine distortion. If only 2 2122 control point pairs (8 numbers) are given a two point image translation 2123 rotation and scaling is performed, without any posible shearing, 2124 flipping or changes in aspect ratio to the resulting image. If only one 2125 control point pair is provides the image is only translated, (which may 2126 be a floating point non-integer translation). <br/> 2127 2128 This distortion does not include any form of perspective distortion. 2129 </td> 2130 2131 </tr> 2132 2133 <tr valign="top"> 2134 <td valign="top"><kbd>AffineProjection</kbd></td> 2135 <td valign="top"> 2136 Linearly distort an image using the given Affine Matrix of 6 2137 pre-calculated coefficients forming a set of Affine Equations to map 2138 the source image to the destination image. 2139 2140 <div style="text-align: center"><em> 2141 s<sub>x</sub>, r<sub>x</sub>, 2142 r<sub>y</sub>, s<sub>y</sub>, 2143 t<sub>x</sub>, t<sub>y</sub> 2144 </em></div> 2145 2146 See <a href="#affine" >-affine</a> setting for more detail, and 2147 meanings of these coefficients. <br/> 2148 2149 The distortions '<kbd>Affine</kbd>' and '<kbd>SRT</kbd>' provide 2150 alternative methods of defining this distortion, with ImageMagick doing the 2151 calculations needed to generate the required coefficients. You can see 2152 the internally generated coefficients, by using a <a href="#verbose" 2153 >-verbose</a> setting. </td> 2154 2155 </tr> 2156 2157<!-- still under development, do not display - Anthony 2158 <tr valign="top"> 2159 <td valign="top"><kbd>Bilinear</kbd></td> 2160 <td valign="top"> 2161 Bilinear (reversed) Distortion, given a minimum of 4 sets of 2162 coordinate pairs, or 16 values (see below). Not that lines may not 2163 appear straight after distortion, though the distance between 2164 coordinates will remain consistant. </td> 2165 </tr> 2166--> 2167 2168 <tr valign="top"> 2169 <td valign="top"><kbd>Perspective</kbd></td> 2170 <td valign="top"> 2171 Perspective distort the images, using a list of 4 or more sets of 2172 control points (as defined below). More that 4 sets (16 numbers) of 2173 control points provide least squares fitting for more accurate 2174 distortions (for the purposes of image registration and panarama 2175 effects). Less than 4 sets will fall back to a '<kbd>Affine</kbd>' 2176 linear distortion. <br/> 2177 2178 Perspective Distorted images ensures that straight lines remain 2179 straight, but the scale of the distorted image will vary. The horizon 2180 is anti-aliased, and the 'sky' color may be set using the 2181 <a href="#mattecolor" >-mattecolor</a> setting. </td> 2182 </tr> 2183 2184 <tr valign="top"> 2185 <td valign="top"><kbd>PerspectiveProjection</kbd> </td> 2186 <td valign="top"> 2187 Do a '<kbd>Perspective</kbd>' distortion basied on a set of 8 2188 pre-calculated coefficients. You can get these coefficients by looking 2189 at the <a href="#verbose" >-verbose</a> output of a 2190 '<kbd>Prespective</kbd>' distortion, or by calculating them yourself. 2191 If the last two perspective scaling coefficients are zero, the 2192 remaining 6 represents a transposed 'Affine Matrix'. </td> 2193 2194 </tr> 2195 2196 <tr valign="top"> 2197 <td valign="top"><kbd>Arc</kbd></td> 2198 <td valign="top"> 2199 Arc the image (variation of polar mapping) over the angle given around 2200 a circle. <br/> 2201 <table width="90%" style = "margin-left: auto; margin-right: auto;"> 2202 <tr valign="top"><td>Argument</td> 2203 <td>Meaning</td></tr> 2204 <tr valign="top"><td><em>arc_angle</em></td> 2205 <td>The angle over which to arc the image side-to-side</td></tr> 2206 <tr valign="top"><td><em>rotate_angle</em></td> 2207 <td>Angle to rotate resulting image from vertical center</td></tr> 2208 <tr valign="top"><td><em>top_radius</em></td> 2209 <td>Set top edge of source image at this radius</td></tr> 2210 <tr valign="top"><td><em>bottom_radius</em> </td> 2211 <td>Set bottom edge to this radius (radial scaling)</td></tr> 2212 </table> 2213 2214 The resulting image is always resized to best fit the resulting image, 2215 (as if using <a href="#distort" >+distort</a>) while attempting to 2216 preserve scale and aspect ratio of the original image as much as 2217 possible with the arguments given by the user. All four arguments will 2218 be needed to change the overall aspect ratio of an 'Arc'ed image. <br/> 2219 2220 This a variation of a polar distortion designed to try to preserve the 2221 aspect ratio of the image rather than direct Cartesian to Polar 2222 conversion. </td> 2223 </tr> 2224 2225 <tr valign="top"> 2226 <td valign="top"><kbd>Polar</kbd></td> 2227 <td valign="top"> 2228 Like '<kbd>Arc</kbd>' but do a complete Cartesian to Polar mapping of 2229 the image. that is the height of the input image is mapped to the 2230 radius limits, while the width is wrapped around between the 2231 angle limits. <br/> 2232 2233 Arguments: <em>Rmax,Rmin CenterX,CenterY, start,end_angle</em> <br/> 2234 2235 All arguments are optional. With <em>Rmin</em> defaulting to zero, the 2236 center to the center of the image, and the angles going from -180 (top) 2237 to +180 (top). If <em>Rmax</em> is given the special value of 2238 '<code>0</code>', the the distance from the center to the nearest edge 2239 is used for the radius of the output image, which will ensure the whole 2240 image is visible (though scaled smaller). However a special value of 2241 '<code>-1</code>' will use the distance from the center to the furthest 2242 corner, This may 'clip' the corners from the input rectangular image, 2243 but will generate the exact reverse of a '<kbd>DePolar</kbd>' with 2244 the same arguments. <br/> 2245 2246 If the plus form of distort (<a href="#distort" >+distort</a>) is used 2247 output image center will default to <code>0,0</code> of the virtual 2248 canvas, and the image size adjusted to ensure the whole input image is 2249 made visible in the output image on the virtual canvas. </td> 2250 2251 </tr> 2252 2253 <tr valign="top"> 2254 <td valign="top"><kbd>DePolar</kbd></td> 2255 <td valign="top"> 2256 Uses the same arguments and meanings as a '<kbd>Polar</kbd>' distortion 2257 but generates the reverse Polar to Cartesian distortion. <br/> 2258 2259 The special <em>Rmax</em> setting of '<code>0</code>' may however clip 2260 the corners of the input image. However using the special 2261 <em>Rmax</em> setting of '<code>-1</code>' (maximum center to corner 2262 distance) will ensure the whole distorted image is preserved in the 2263 generated result, so that the same argument to '<kbd>Polar</kbd>' will 2264 reverse the distortion re-producing the original. 2265 2266 Note that as this distortion requires the area resampling of a circular 2267 arc, which can not be handled by the builtin EWA resampling function. 2268 As such the normal EWA filters are turned off. It is recomended some 2269 form of 'super-sampling' image processing technique be used to produce 2270 a high quality result. </td> 2271 2272 </tr> 2273 2274 <tr valign="top"> 2275 <td valign="top"><kbd>Barrel</kbd></td> 2276 <td valign="top"> 2277 Given the four coefficients (A,B,C,D) as defined by <a 2278 href="http://www.all-in-one.ee/~dersch/barrel/barrel.html" >Helmut 2279 Dersch</a>, perform a barrell or pincussion distortion appropriate to 2280 correct radial lens distortions. That is in photographs, make straight 2281 lines straight again. <br/> 2282 2283 Arguments: <em>A B C</em> [ <em>D</em> [ 2284 <em>X</em> , <em>Y</em> ] ] <br/> 2285 or <em>A<sub>x</sub> B<sub>x</sub> C<sub>x</sub> D<sub>x</sub> 2286 A<sub>y</sub> B<sub>y</sub> C<sub>y</sub> D<sub>y</sub></em> 2287 [ <em>X</em> , <em>Y</em> ] <br/> 2288 So that it forms the function <br/> 2289 Rsrc = r * ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> + 2290 <em>C</em>*r + <em>D</em> )<br/> 2291 2292 Where <em>X</em>,<em>Y</em> is the optional center of the distortion 2293 (defaulting to the center of the image). <br/> 2294 The second form is typically used to distort images, rather than 2295 correct lens distortions. <br/> 2296 </td> 2297 2298 </tr> 2299 2300 <tr valign="top"> 2301 <td valign="top"><kbd>BarrelInverse</kbd></td> 2302 <td valign="top"> 2303 This is very simular to '<kbd>Barrel</kbd>' with the same set of 2304 arguments, and argument handling. However it uses the inverse 2305 of the radial polynomial, 2306 so that it forms the function <br/> 2307 Rsrc = r / ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> + 2308 <em>C</em>*r + <em>D</em> ) 2309 </td> 2310 </tr> 2311 2312 <tr valign="top"> 2313 <td valign="top"><kbd>Shepards</kbd></td> 2314 <td valign="top"> 2315 Distort the given list control points (any number) using an Inverse 2316 Squared Distance Interpolation Method (<a 2317 href="http://www.ems-i.com/smshelp/Data_Module/Interpolation/Inverse_Distance_Weighted.htm" 2318 >Shepards Method</a>). The control points in effect do 'localized' 2319 distortions of the image around the given control point. For best 2320 results extra control points should be added to 'lock' the positions of 2321 the corners and other unchanging parts of the image. <br/> 2322 2323 The distortion has been likened to 'taffy pulling' using nails, pins or 2324 sticks. It basically uses the <a href="#sparse-color" 2325 >-sparse-color</a> method of the same name to generate separate X and Y 2326 displacement maps (see <a href="#displace" >-displace</a>) for source 2327 image color look-up. </td> 2328 2329 </tr> 2330 2331</table> 2332 2333<p>To print a complete list of distortion methods, use <a href="#list">-list distort</a>.</p> 2334 2335<p>Many of the above distortion methods such as '<kbd>Affine</kbd>', 2336'<kbd>Perspective</kbd>', and '<kbd>Shepards</kbd>' use a list control points 2337defining how these points in the given image should be distorted in the 2338destination image. Each set of four floating point values represent a source 2339image coordinate, followed immediately by the destination image coordinate. 2340This produces a list of values such as...</p> 2341<div style="text-align: center"><em> 2342 U<sub>1</sub>,V<sub>1</sub> X<sub>1</sub>,Y<sub>1</sub> 2343 U<sub>2</sub>,V<sub>2</sub> X<sub>2</sub>,Y<sub>2</sub> 2344 U<sub>3</sub>,V<sub>3</sub> X<sub>3</sub>,Y<sub>3</sub> 2345 ... 2346 U<sub>n</sub>,V<sub>n</sub> X<sub>n</sub>,Y<sub>n</sub> 2347</em></div> 2348<p>where <em>U,V</em> on the source image is mapped to <em>X,Y</em> on the 2349destination image. </p> 2350 2351<p>For example, to warp an image using '<kbd>perspective</kbd>' distortion, 2352needs a list of at least 4 sets of coordinates, or 16 numbers. Here is the 2353perspective distortion of the built-in "rose:" image. Note how spaces were 2354used to group the 4 sets of coordinate pairs, to make it easier to read and 2355understand.</p> 2356 2357<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'> 2358 convert rose: -virtual-pixel black \ <br/> 2359 -distort Perspective '0,0,0,0 0,45,0,45 69,0,60,10 69,45,60,35' \ <br/> 2360 rose_3d_rotated.gif</span></p> 2361<p>If more that the required number of coordinate pairs are given for a 2362distortion, the distortion method is 'least squares' fitted to 2363produce the best result for all the coordinate pairs given. If less than the 2364ideal number of points are given, the distort will generally fall back to a 2365simpler form of distortion that can handles the smaller number of coordinates 2366(usally a linear '<kbd>Affine</kbd>' distortion). </p> 2367 2368<p>By using more coodinates you can make use of image registration tool to 2369find matching coordinate pairs in overlaping images, so as to improve the 'fit' 2370of the distortion. Of course a bad coordinate pair can also make the 'fit' 2371worse. Caution is always advised. </p> 2372 2373<p>Colors are acquired from the source image according to the <a 2374href="#interpolate" >-interpolate</a> color lookup setting, when the image is 2375magnified. However if the viewed image is minified (image becomes smaller), a 2376special area resampling function (added ImageMagick v6.3.5-9), is used to 2377produce a higher quality image. For example you can use a 2378'<kbd>perspective</kbd>' distortion to view a infinitely tiled 'plane' all the 2379way to the horizon. </p> 2380 2381<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 90x90 pattern:checkerboard -normalize -virtual-pixel tile \ <br/> 2382 -distort perspective '0,0,5,45 89,0,45,46 0,89,0,89 89,89,89,89' \ <br/> 2383 checks_tiled.jpg</span></p> 2384<p>Note that a infinitely tiled perspective images involving the horizon can 2385be very slow to generate due to the use of the high quality 'area resampling' 2386function (added ImageMagick v6.3.5-9). You can turn off 'area resampling' 2387using a <a href="#filter" >-filter</a> setting of '<kbd>point</kbd>' 2388(recommended if you plan to use super-sampling instead). </p> 2389 2390<p>If an image generates <i>invalid pixels</i>, such as the 'sky' in the last 2391'<kbd>perspective</kbd>' distortion example, <a href="#distort" >-distort</a> 2392will use the current <a href="#mattecolor" >-mattecolor</a> setting for these 2393pixels. If you do not what these pixels to be visible, set the color to match 2394the rest of the ground. </p> 2395 2396<p>The output image size will by default be the same as the input image. This 2397means that if the part of the distorted image falls outside the viewed area of 2398the 'distorted space', those parts is clipped and lost. However if you 2399use the plus form of the operator (<a href="#distort" >+distort</a>) the 2400operator will attempt (if posible) to show the whole of the distorted image, 2401while retaining a correct 'virtual canvas' offset, for image layering. This 2402offset may need to be removed using <a href="#repage" >+repage</a>, to remove 2403if it is unwanted. </p> 2404 2405<p>You can alternatively specify a special "<kbd><a href="#set" >-set</a> 2406option:distort:viewport {geometry_string}</kbd>" setting which will specify 2407the size and the offset of the generated 'viewport' image of the distorted 2408image space.</p> 2409 2410<p>Adding a "<kbd><a href="#set" >-set</a> option:distort:scale 2411{scale_factor}</kbd>" will scale the output image (viewport or otherwise) by 2412that factor without changing the viewed contents of the distorted image. This 2413can be used either for 'super-sampling' the image for a higher quality result, 2414or for panning and zooming around the image (with appropriate viewport 2415changes, or post-distort cropping and resizing). </p> 2416 2417<p>Setting <a href="#verbose" >-verbose</a> setting, will cause <a 2418href="#distort" >-distort</a> to attempt to output the internal coefficients, 2419and the <a href="#fx" >-fx</a> equivalent to the distortion, for expert study, 2420and debugging purposes. This many not be available for all distorts. </p> 2421 2422<p>Affine rotations and shears (such as '<kbd>SRT</kbd>' distortion), tend to 2423produce a cleaner result that the equivalent <a href="#rotate" >-rotate</a> 2424and/or <a href="#shear" >-shear</a> operation, with more control of due to the 2425above settings. It is algorithmically slower, though in ImageMagick it may be faster. 2426</p> 2427 2428 2429<div style="margin: auto;"> 2430 <h4><a name="dither" id="dither"></a>-dither <em class="arg">method</em></h4> 2431</div> 2432 2433<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> 2434 2435<p>Dithering places two or more colors in neighbouring 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> 2436 2437<p>Dithering is turned on by default, to turn it off use the plus form of the 2438setting, <a href="#dither">+dither</a>. This will also also render PostScript 2439without text or graphic aliasing. Disabling dithering often (but not always) 2440leads to faster process, a smaller number of colors, but more cartoon like 2441image coloring. Generally resulting in 'color banding' effects in areas with 2442color gradients. </p> 2443 2444<p>The color reduction operators <a href="#colors">-colors</a>, <a 2445href="#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> 2446 2447<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> 2448 2449 2450<div style="margin: auto;"> 2451 <h4><a name="draw" id="draw"></a>-draw <em class="arg">string</em></h4> 2452</div> 2453 2454<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> 2455 2456<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> 2457 2458<p>The shape primitives:</p> 2459 2460<pre class="text"> 2461 point x,y 2462 line x0,y0 x1,y1 2463 rectangle x0,y0 x1,y1 2464 roundRectangle x0,y0 x1,y1 wc,hc 2465 arc x0,y0 x1,y1 a0,a1 2466 ellipse x0,y0 rx,ry a0,a1 2467 circle x0,y0 x1,y1 2468 polyline x0,y0 ... xn,yn 2469 polygon x0,y0 ... xn,yn 2470 bezier x0,y0 ... xn,yn 2471 path path specification 2472 image operator x0,y0 w,h filename 2473</pre> 2474 2475<p>The text primitive:</p> 2476 2477<pre class="text"> 2478 text x0,y0 string 2479</pre> 2480<p>The text gravity primitive:</p> 2481 2482<pre class="text"> 2483 gravity NorthWest, North, NorthEast, West, Center, 2484 East, SouthWest, South, or SouthEast 2485</pre> 2486 2487<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> 2488 2489<p>The transformation primitives:</p> 2490 2491<pre class="text"> 2492 rotate degrees 2493 translate dx,dy 2494 scale sx,sy 2495 skewX degrees 2496 skewY degrees 2497</pre> 2498 2499<p>The pixel operation primitives:</p> 2500 2501<pre class="text"> 2502 color x0,y0 method 2503 matte x0,y0 method 2504</pre> 2505 2506<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> 2507 2508<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> 2509 2510<p>A <kbd>line</kbd> primitive requires a start point and end point.</p> 2511 2512<p>A <kbd>rectangle</kbd> primitive is specified by the pair of points at the upper left and lower right corners.</p> 2513 2514<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> 2515 2516<p>The <kbd>circle</kbd> primitive makes a disk (filled) or circle (unfilled). Give the center and any point on the perimeter (boundary).</p> 2517 2518<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> 2519 2520<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> 2521 2522<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>. 2523</p> 2524 2525<p>A <em>coordinate</em> is a pair of integers separated by a space or optional comma. </p> 2526 2527<p>As an example, to define a circle centered at 100,100 that extends to 150,150 use:</p> 2528 2529<p class="crtsnip"> 2530 -draw 'circle 100,100 150,150' 2531</p> 2532 2533<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 2534draw 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> 2535 2536<p class="crtsnip"> 2537 -draw 'bezier 20,50 45,100 45,0 70,50' 2538</p> 2539<p class="crtsnip"> 2540 -draw 'bezier 70,50 95,100 95,0 120,50' 2541</p> 2542 2543 2544<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> 2545 2546<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> 2547 2548<p class="crtsnip"> 2549 -draw 'image SrcOver 100,100 225,225 image.jpg' 2550</p> 2551 2552<p>You can use 0,0 for the image size, which means to use the actual dimensions found in the image header. Otherwise, it is scaled to the given dimensions. See <a href="#compose">-compose</a> for a description of the composite operators.</p> 2553 2554<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> 2555 2556<p>For example, the following annotates the image with <kbd>Works like magick!</kbd> for an image titled <kbd>bird.miff</kbd>. </p> 2557 2558<p class="crtsnip"> 2559 -draw 'text 100,100 "Works like magick!"' 2560</p> 2561 2562<p>See the <a href="#annotate">-annotate</a> option for another convenient way to annotate an image with text.</p> 2563 2564<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> 2565 2566<p>The <kbd>translate</kbd> primitive translates subsequent shape and text primitives.</p> 2567 2568<p>The <kbd>scale</kbd> primitive scales them.</p> 2569 2570<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> 2571 2572<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 2573matrix.</p> 2574 2575<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> 2576 2577<pre class="text"> 2578 point 2579 replace 2580 floodfill 2581 filltoborder 2582 reset 2583</pre> 2584 2585<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> 2586 2587<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> 2588 2589<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> 2590 2591<p>Strings that begin with a number must be quoted (e.g. use '1.png' rather than 1.png).</p> 2592 2593<p>Drawing primitives conform to the <a href="/www/magick-vector-graphics.html">Magick Vector Graphics</a> format.</p> 2594 2595 2596<div style="margin: auto;"> 2597 <h4><a name="edge" id="edge"></a>-edge <em class="arg">radius</em></h4> 2598</div> 2599 2600<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> 2601 2602<div style="margin: auto;"> 2603 <h4><a name="emboss" id="emboss"></a>-emboss <em class="arg">radius</em></h4> 2604</div> 2605 2606<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>emboss an image.</td><td style='text-align:right;'></td></tr></table> 2607 2608<div style="margin: auto;"> 2609 <h4><a name="encipher" id="encipher"></a>-encipher <em class="arg">filename</em></h4> 2610</div> 2611 2612<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> 2613 2614<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p> 2615 2616<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p> 2617 2618<div style="margin: auto;"> 2619 <h4><a name="encoding" id="encoding"></a>-encoding <em class="arg">type</em></h4> 2620</div> 2621 2622<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> 2623 2624<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> 2625 2626<div style="margin: auto;"> 2627 <h4><a name="endian" id="endian"></a>-endian <em class="arg">type</em></h4> 2628</div> 2629 2630<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specify endianness (<kbd>MSB</kbd> or <kbd>LSB</kbd>) of the image.</td><td style='text-align:right;'></td></tr></table> 2631 2632<p>To print a complete list of endian types, use the <a href="#list">-list endian</a> option.</p> 2633 2634<p>Use <a href="#endian">+endian</a> to revert to unspecified endianness.</p> 2635 2636 2637<div style="margin: auto;"> 2638 <h4><a name="enhance" id="enhance"></a>-enhance</h4> 2639</div> 2640 2641<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> 2642 2643 2644<div style="margin: auto;"> 2645 <h4><a name="equalize" id="equalize"></a>-equalize</h4> 2646</div> 2647 2648<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> 2649 2650<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> 2651 2652<p>For example using HSL, we have: ... <kbd>-colorspace HSL -channel lightness -equalize -colorspace RGB</kbd> ...</p> 2653 2654<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> 2655 2656<div style="margin: auto;"> 2657 <h4><a name="evaluate" id="evaluate"></a>-evaluate <em class="arg">operator value</em></h4> 2658</div> 2659 2660<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> 2661 2662<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> 2663 2664<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> 2665 2666<table class="doc"> 2667 <col width="25%" /> 2668 <col width="75%" /> 2669 <thead> 2670 <tr> 2671 <th><em class="arg">operator</em></th> 2672 <th>Summary (see further below for details)</th> 2673 </tr> 2674 </thead> 2675 <tbody> 2676 2677 <tr><td>Add </td> <td>Add <em class="arg">value</em> to pixels. </td></tr> 2678 <tr><td>AddModulus </td> <td>Add <em class="arg">value</em> to pixels modulo <em class="QR">QuantumRange</em>.</td></tr> 2679 <tr><td>And </td> <td>Binary AND of pixels with <em class="arg">value</em>.</td></tr> 2680 <tr><td>Cos, Cosine </td> <td>Apply cosine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr> 2681 <tr><td>Divide </td> <td>Divide pixels by <em class="arg">value</em>.</td></tr> 2682 <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> 2683 <tr><td>Log </td> <td>Apply scaled logarithm to normalized pixels.</td></tr> 2684 <tr><td>Max </td> <td>Clip pixels at lower bound <em class="arg">value</em>.</td></tr> 2685 <tr><td>Min </td> <td>Clip pixels at upper bound <em class="arg">value</em>.</td></tr> 2686 <tr><td>Multiply </td> <td>Multiply pixels by <em class="arg">value</em>.</td></tr> 2687 <tr><td>Or </td> <td>Binary OR of pixels with <em class="arg">value</em>.</td></tr> 2688 <tr><td>Pow </td> <td>Raise normalized pixels to the power <em class="arg">value</em>.</td></tr> 2689 <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> 2690 <tr><td>Set </td> <td>Set pixel equal to <em class="arg">value</em>.</td></tr> 2691 <tr><td>Sin, Sine </td> <td>Apply sine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr> 2692 <tr><td>Subtract </td> <td>Subtract <em class="arg">value</em> from pixels.</td></tr> 2693 <tr><td>Xor </td> <td>Binary XOR of pixels with <em class="arg">value.</em></td></tr> 2694 2695 <tr><td> </td></tr> 2696 2697 <tr><td>Gaussian-noise</td></tr> 2698 <tr><td>Impulse-noise</td></tr> 2699 <tr><td>Laplacian-noise</td></tr> 2700 <tr><td>Multiplicative-noise</td> <td>(These are equivalent to the corresponding <a href="#noise" >-noise</a> operators.)</td></tr> 2701 <tr><td>PoissonNoise</td></tr> 2702 <tr><td>Uniform-noise</td></tr> 2703 2704 <tr><td> </td></tr> 2705 2706 <tr><td>Threshold </td> <td>Threshold pixels larger than <em class="arg">value</em>.</td></tr> 2707 <tr><td>ThresholdBlack </td> <td>Threshold pixels to zero values equal to or below <em class="arg">value</em>.</td></tr> 2708 <tr><td>ThresholdWhite </td> <td>Threshold pixels to maximum values above <em class="arg">value</em>. </td></tr> 2709 </tbody> 2710 </table> 2711 2712<p>The specified functions are applied only to each previously set <a 2713href="#channel" >-channel</a> in the image. If necessary, the results of the 2714calculations are truncated (clipped) to fit in the interval [0, <em 2715class="QR">QuantumRange</em>]. The transparency channel of the image is 2716represented as a 'alpha' values (0 = fully transparent), so, for example, a 2717<kbd>Divide</kbd> by 2 of the alpha channel will make the image 2718semi-transparent. Append the percent symbol '<kbd>%</kbd>' to specify a value 2719as a percentage of the <em class="QR">QuantumRange</em>.</p> 2720 2721<p>To print a complete list of <a href="#evaluate">-evaluate</a> operators, use 2722<a href="#list">-list evaluate</a>.</p> 2723 2724<p>The results of the <kbd>Add</kbd>, <kbd>Subtract</kbd> and 2725<kbd>Multiply</kbd> methods can also be achieved using either the <a 2726href="#level" >-level</a> or the <a href="#level" >+level</a> operator, with 2727appropriate argument, to linearly modify the overall range of color values. 2728Please note, however, that <a href="#level" >-level</a> treats transparency as 2729'matte' values (0 = opaque), while <a href="#level" >-evaluate</a> works with 2730'alpha' values.</p> 2731 2732<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> 2733 2734<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> 2735 2736 <div style="text-align:center;"> 2737 log(<em class="arg">value</em> × <b><em>u</em></b> + 1) / log(<em class="arg">value</em> + 1) 2738 </div> 2739 2740<p><kbd>Pow</kbd> has been added as of ImageMagick 6.4.1-9, and works on 2741normalized pixel values. Note that <kbd>Pow</kbd> is related to the <a 2742href="#gamma" >-gamma</a> operator. For example, <b>-gamma 2</b> is equivalent 2743to <b>-evaluate pow 0.5</b>, i.e., a 'square root' function. The value used 2744with <a href="#gamma" >-gamma</a> is simply the reciprocal of the value used 2745with <kbd>Pow</kbd>.</p> 2746 2747<p><kbd>Cosine</kbd> and <kbd>Sine</kbd> was added as of IM v6.4.8-8 and 2748converts the image values into a value according to a (co)sine wave function. 2749The synonyms <kbd>Cos</kbd> and <kbd>Sin</kbd> may also be used. The output 2750is biased 50% and normalized by 50% so as to fit in the respective color value 2751range. The <em class="arg">value</em> scaling of the <em>period</em> of the 2752function (its frequency), and thus determines the number of 'waves' that will 2753be generated over the input color range. For example, if the <em 2754class="arg">value</em> is 1, the effective period is simply the <em 2755class="QR">QuantumRange</em>; but if the <em class="arg">value</em> is 2, 2756then the effective period is the <em>half</em> the <em 2757class="QR">QuantumRange</em>. 2758 2759 <div style="text-align:center;"> 2760 0.5 + 0.5 × cos(2 π <b><em>u</em></b> × <em class="arg">value</em>). 2761 </div> 2762 2763See also the <a href="#function" >-function</a> operator, which is a 2764multi-value version of evaluate. </P> 2765 2766 2767<div style="margin: auto;"> 2768 <h4><a name="extent" id="extent"></a>-extent <em class="arg">geometry</em></h4> 2769</div> 2770 2771<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> 2772 2773<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> 2774 2775<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> 2776 2777<div style="margin: auto;"> 2778 <h4><a name="extract" id="extract"></a>-extract <em class="arg">geometry</em></h4> 2779</div> 2780 2781<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> 2782 2783<p>This option is most useful for extracting a subregion of a very large raw image. Note that these two commands are equivalent:</p> 2784 2785<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 -extract 640x480+1280+960 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]' image.rgb image.png</span></p><p>If you omit the offsets, as in</p> 2786 2787<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 -extract 640x480 image.rgb image.png</span></p> 2788<p>then the image will be <em>resized</em> to the specified dimensions instead, 2789equivalent to:</p> 2790 2791<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 -resize 640x480 image.rgb image.png</span></p> 2792<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> 2793 2794<div style="margin: auto;"> 2795 <h4><a name="family" id="family"></a>-family <em class="arg">fontFamily</em></h4> 2796</div> 2797 2798<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set a font family for text.</td><td style='text-align:right;'></td></tr></table> 2799 2800<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). 2801</p> 2802 2803<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>. 2804</p> 2805 2806<div style="margin: auto;"> 2807 <h4><a name="features" id="features"></a>-features <em class="arg">distance</em></h4> 2808</div> 2809 2810<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> 2811 2812<div style="margin: auto;"> 2813 <h4><a name="fft" id="fft"></a>-fft</h4> 2814</div> 2815 2816<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> 2817 2818<p>This option is new as of ImageMagick 6.5.4-3 and 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> 2819 2820<p>A single image name is provided as output for this option. However, the output result will have two components. It will be 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> 2821 2822<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> 2823 2824<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -fft fft_image.miff</span></p> 2825<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> 2826 2827<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -fft fft_image.png</span></p> 2828<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> 2829 2830<p>The input image can be any size, but if not square and even-dimensioned, it will be 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 will be square at this size. The kind of padding relies on the <a href="#virtual-pixel">-virtual-pixel</a> setting.</p> 2831 2832<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> 2833 2834<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert fft_image.miff[0] -contrast-stretch 0 \ <br /> 2835 -evaluate log 1000 fft_image_spectrum.png</span></p> 2836<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> 2837 2838<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#fft">-fft</a>. 2839 2840<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> 2841 2842<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> 2843 2844<p>The real and imaginary component images resulting from <a href="#fft">+fft</a> also will be square, even dimensioned images due to the same padding that was discussed above for the magnitude and phase component images.</a> 2845 2846<p>See the discussion on HDRI implementations of ImageMagick on the page 2847<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. 2848</p> 2849 2850 2851<div style="margin: auto;"> 2852 <h4><a name="fill" id="fill"></a>-fill <em class="arg">color</em></h4> 2853</div> 2854 2855<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> 2856 2857<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> 2858 2859<p>Enclose the color specification in quotation marks to prevent the "#" or the parentheses from being interpreted by your shell.</p> 2860 2861<p>For example,</p> 2862 2863<p class="crtsnip"> 2864 -fill blue 2865</p> 2866<p class="crtsnip"> 2867 -fill "#ddddff" 2868</p> 2869<p class="crtsnip"> 2870 -fill "rgb(255,255,255)" 2871</p> 2872 2873<p>See <a href="#draw">-draw</a> for further details.</p> 2874 2875<p>To print a complete list of color names, use the <a href="#list">-list color</a> option.</p> 2876 2877<div style="margin: auto;"> 2878 <h4><a name="filter" id="filter"></a>-filter <em class="arg">type</em></h4> 2879</div> 2880 2881<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 an image.</td><td style='text-align:right;'></td></tr></table> 2882 2883<p>Use this option to affect the resizing operation of an image (see <a 2884href="#resize">-resize</a>). For example you can use a simple resize filter 2885such as:</p> 2886 2887<pre class="text"> 2888 Point Hermite Cubic 2889 Box Gaussian Catrom 2890 Triangle Quadratic Mitchell 2891</pre> 2892 2893<p>The <kbd>Bessel</kbd> and <kbd>Sinc</kbd> filter is also provided, but are 2894by default <kbd>blackman</kbd>-windowed. However these filters define a 2895windowing filter for the Sinc or Bessel filter function, as appropriate for 2896the scaling operator used (usally Sinc for orthogonal <a href="#resize" 2897>-resize</a>). Windowed filters include: </p> 2898 2899<pre class="text"> 2900 Lanczos Hamming Parzen 2901 Blackman Kaiser Welsh 2902 Hanning Bartlett Bohman 2903</pre> 2904 2905<p>Also one special self-windowing filter is also provided 2906<kbd>Lagrange</kbd>, which will automagically re-adjust its function depending 2907on the current 'support' or 'lobes' expert settings (see below).</p> 2908 2909<p>If you do not select a filter with this option, the filter defaults to <kbd>Mitchell</kbd> for a colormapped image, a image with a matte channel, or if the image is enlarged. Otherwise the filter default to <kbd>Lanczos</kbd>.</p> 2910 2911<p>To print a complete list of resize filters, use the <a href="#list">-list filter</a> option.</p> 2912 2913<p>You can modify how the filter behaves as it scales your image through the 2914use of these expert settings:</p> 2915 2916<dl class="doc"> 2917<dt>-set filter:blur <em>factor</em></dt> 2918<dd>Scale the X axis of the filter (and its window). Use > 1.0 for 2919 blurry or < 1.0 for sharp.</dd> 2920 2921<dt>-set filter:support <em>radius</em></dt> 2922<dd>Set the filter support radius.</dd> 2923 2924<dt>-set filter:lobes <em>count</em></dt> 2925<dd>Set the number of lobes to use for the Sinc/Bessel filter. This an 2926 alternative way of specifying the 'support' range of the filter.</dd> 2927 2928<dt>-set filter:b <em>b-spline_factor</em></dt> 2929<dt>-set filter:c <em>keys_alpha_factor</em></dt> 2930<dd>Redefine the values used for cubic filters such as <kbd>Cubic</kbd>, 2931 <kbd>Catrom</kbd>, <kbd>Mitchel</kbd>, and <kbd>Hermite</kbd>, as well as 2932 the <kbd>Parzen</kbd> Sinc windowing function. If only one of the values 2933 are defined, the other is set so as to generate a 'Keys' type cubic 2934 filter. 2935 2936<dt>-set filter:filter <em>filter</em></dt> 2937<dd>Use this function directly as the scaling filter. This will allow 2938 you to directly use a 'windowing filter' such as <kbd>blackman</kbd>, 2939 rather than as its normal usage as a windowing function for 'Sinc' or 2940 'Bessel'. If defined, no windowing function is used, unless the following 2941 expert setting is also defined.</dd> 2942 2943<dt>-set filter:window <em>filter</em></dt> 2944<dd>The IIR (infinite impulse response) filters <kbd>bessel</kbd> and 2945 <kbd>sinc</kbd> are windowed (brought down to zero over the defined 2946 support range) with the given filter. This allows you to use a filter that 2947 is not normally used as a windowing function, such as <kbd>box</kbd>, 2948 (which effectivally turns off the windowing function). </dd> 2949 2950</dl> 2951 2952<p>For example, to get a 8 lobe Lanczos-Bessel filter:</p> 2953 2954<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -filter bessel \ <br/> 2955 -set filter:window=bessel -set filter:lobes=8 \ <br/> 2956 -resize 150% image.jpg</span></p> 2957<p>Or a raw un-windowed Sinc filter with 4 lobes:</p> 2958 2959<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -set filter:filter=sinc -set filter:lobes=4 \ <br/> 2960 -resize 150% image.jpg</span></p> 2961<p>Note that the use of expert options (except for 'blur' with simple resize 2962filters), are provided for image processing experts who have studied and 2963understood how resize filters work. Without this knowledge, and an 2964understanding of the defination of the actual filters involved, using expert 2965settings are more likely to be detremental to your image resizing.</p> 2966 2967 2968<div style="margin: auto;"> 2969 <h4><a name="flatten" id="flatten"></a>-flatten</h4> 2970</div> 2971 2972<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> 2973 2974 2975<div style="margin: auto;"> 2976 <h4><a name="flip" id="flip"></a>-flip</h4> 2977</div> 2978 2979<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> 2980 2981<p>reflect the scanlines in the vertical direction.</p> 2982 2983<div style="margin: auto;"> 2984 <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> 2985</div> 2986 2987<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> 2988 2989<div style="margin: auto;"> 2990 <h4><a name="flop" id="flop"></a>-flop</h4> 2991</div> 2992 2993<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> 2994 2995<p>reflect the scanlines in the horizontal direction.</p> 2996 2997 2998<div style="margin: auto;"> 2999 <h4><a name="font" id="font"></a>-font <em class="arg">name</em></h4> 3000</div> 3001 3002<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> 3003 3004<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> 3005 3006<p>In addition to the fonts specified by the above pre-defined list, you can 3007also specify a font from a specific source. For example <kbd>Arial.ttf</kbd> 3008is a TrueType font file, <kbd>ps:helvetica</kbd> is PostScript font, and 3009<kbd>x:fixed</kbd> is X11 font.</p> 3010 3011<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> 3012 3013 3014<div style="margin: auto;"> 3015 <h4><a name="foreground" id="foreground"></a>-foreground <em class="arg">color</em></h4> 3016</div> 3017 3018<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> 3019 3020<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 3021 3022<p>The default foreground color is black.</p> 3023 3024<div style="margin: auto;"> 3025 <h4><a name="format" id="format"></a>-format <em class="arg">type</em></h4> 3026</div> 3027 3028<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> 3029 3030<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> 3031 3032<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> 3033 3034<div style="margin: auto;"> 3035 <h4><a name="format_identify_" id="format_identify_"></a>-format <em class="arg">string</em></h4> 3036</div> 3037 3038<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> 3039 3040<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> 3041 3042<div style="margin: auto;"> 3043 <h4><a name="frame" id="frame"></a>-frame <em class="arg">geometry</em></h4> 3044</div> 3045 3046<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> 3047 3048<p>The color of the border is specified with the <a href="#mattecolor">-mattecolor</a> command line option. </p> 3049 3050<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 class="arg">geometry</em> argument indicates the amount of extra width and height that is added to the dimensions of the image. If no offsets are given in the <em class="arg">geometry</em> argument, then the border added is a solid color. Offsets <em>x</em> and <em>y</em>, if present, specify that the width and height of the border is partitioned to form an outer bevel of thickness <em>x</em> pixels and an inner bevel of thickness <em>y</em> pixels. (Negative offsets make no sense here.) The <a href="#frame">-frame</a> option is not affected by the <a href="#gravity">-gravity</a> option.</p> 3051 3052 3053<div style="margin: auto;"> 3054 <h4><a name="frame_import_" id="frame_import_"></a>-frame</h4> 3055</div> 3056 3057<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> 3058 3059<div style="margin: auto;"> 3060 <h4><a name="function" id="function"></a>-function <em class="arg">function</em> <em class="arg">parameters</em></h4> 3061</div> 3062 3063<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> 3064 3065<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> 3066 3067<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> 3068 3069<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> 3070 3071<pre class="text"> 3072 Polynomial 3073 Sinusoid 3074 Arcsin 3075 Arctan 3076</pre> 3077 3078<p>To print a complete list of <a href="#function">-function</a> operators, use <a href="#list">-list function</a>. Descriptions follow.</p> 3079 3080<dl class="doc"> 3081<dt><kbd>Polynomial</kbd></dt> 3082<dd> 3083<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> 3084 3085<div style="text-align: center"> 3086 -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> 3087</div> 3088 3089<p>will invoke a polynomial function given by</p> 3090 3091<div style="text-align: center"> 3092 <em>a</em><sub><em>n</em></sub> <b><em>u</em></b><sup><em>n</em></sup> + 3093 <em>a</em><sub><em>n</em>-1</sub> <b><em>u</em></b><sup><em>n</em>-1</sup> + 3094 ··· <em>a</em><sub>1</sub> <b><em>u</em></b> + <em>a</em><sub>0</sub>, 3095</div> 3096 3097<p>where <b><em>u</em></b> is pixel's original normalized channel value.</p> 3098 3099<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> 3100 3101<table class="doc"> 3102 <col width="35%" /> 3103 <col width="35%" /> 3104 <col width="30%" /> 3105 <tr> 3106 <td>-evaluate Set <em class="arg">value</em> </td> 3107 <td>-function Polynomial <em class="arg">value</em></td> 3108 <td>(Constant functions; set <em class="arg">value</em>×100% gray when channels are RGB.)</td> 3109 </tr> 3110 <tr> 3111 <td>-evaluate Add <em class="arg">value</em> </td> 3112 <td>-function Polynomial 1,<em class="arg">value</em></td> 3113 </tr> 3114 <tr> 3115 <td>-evaluate Subtract <em class="arg">value</em> </td> 3116 <td>-function Polynomial 1,−<em class="arg">value</em></td> 3117 </tr> 3118 <tr> 3119 <td>-evaluate Multiply <em class="arg">value</em> </td> 3120 <td>-function Polynomial <em class="arg">value</em>,0</td> 3121 </tr> 3122 <tr> 3123 <td>+level black% x white%</td> 3124 <td>-function Polynomial A,B</td> 3125 <td>(Reduce contrast. Here, A=(white-black)/100 and B=black/100.)</td> 3126 </tr> 3127</table> 3128 3129<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> 3130</dd> 3131 3132<dt><kbd>Sinusoid</kbd></dt> 3133<dd> 3134<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> 3135 3136<div style="text-align: center"> 3137 -function <kbd>Sinusoid</kbd> <em class="arg">freq</em>,[<em class="arg">phase</em>,[<em class="arg">amp</em>,[<em class="arg">bias</em>]]] 3138</div> 3139 3140<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> 3141 3142<div style="text-align: center"> 3143<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> 3144</div> 3145 3146<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> 3147 3148<p class="crtsnip"> 3149 -function Sinusoid 3,-90,.2,.7 3150</p> 3151 3152<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> 3153 3154<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> 3155 3156<table class="doc"> 3157 <tr> 3158 <td>-evaluate Sin <em class="arg">freq</em> </td> 3159 <td>-function Sinusoid <em class="arg">freq</em>,0 </td> 3160 </tr> 3161 <tr> 3162 <td>-evaluate Cos <em class="arg">freq</em> </td> 3163 <td>-function Sinusoid <em class="arg">freq</em>,90 </td> 3164 </tr> 3165</table> 3166</dd> 3167 3168<dt><kbd>ArcSin</kbd></dt> 3169<dd> 3170<p>The <kbd>ArcSin</kbd> function generates the inverse curve of a Sinusoid, 3171and can be used to generate cylindrical distortion and displacement maps. 3172The curve can be adjusted relative to both the input values and output range 3173of values. 3174 3175<div style="text-align: center"> 3176 -function <kbd>ArcSin</kbd> <em class="arg">width</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]] 3177</div> 3178 3179<p>with all values given in terms of noramlize color values (0.0 for black, 31801.0 for white). Defaulting to values covering the full range from 0.0 to 1.0 3181for bout input (<em class="arg">width</em>), and output (<em 3182class="arg">width</em>) values. '<code>1.0,0.5,1.0,0.5</code>' </p> 3183 3184<div style="text-align: center"> 3185<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> 3186</div> 3187 3188</dd> 3189 3190<dt><kbd>ArcTan</kbd></dt> 3191<dd> 3192<p>The <kbd>ArcTan</kbd> function generates a curve that smooth crosses from 3193limit values at infinities, though a center using the given slope value. 3194All these values can be adjusted via the arguments. 3195 3196<div style="text-align: center"> 3197 -function <kbd>ArcTan</kbd> <em class="arg">slope</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]] 3198</div> 3199 3200<p>Defaulting to '<code>1.0,0.5,1.0,0.5</code>'. 3201</p> 3202 3203<div style="text-align: center"> 3204<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> 3205</div> 3206 3207</dd> 3208 3209</dl> 3210 3211 3212<div style="margin: auto;"> 3213 <h4><a name="fuzz" id="fuzz"></a>-fuzz <em class="arg">distance</em>{<em class="arg">%</em>}</h4> 3214</div> 3215 3216<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> 3217 3218<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> 3219 3220<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> 3221 3222 3223<div style="margin: auto;"> 3224 <h4><a name="fx" id="fx"></a>-fx <em class="arg">expression</em></h4> 3225</div> 3226 3227<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> 3228 3229<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> 3230 3231<p>See <a href="/www/fx.html">FX, The Special Effects Image Operator</a> for a detailed discussion of this option.</p> 3232 3233 3234<div style="margin: auto;"> 3235 <h4><a name="gamma" id="gamma"></a>-gamma <em class="arg">value</em></h4> 3236</div> 3237 3238<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> 3239 3240<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> 3241 3242<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> 3243 3244<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> 3245 3246<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> 3247 3248<p>Note that gamma adjustments are also available via the <a href="#level">-level</a> operator.</p> 3249 3250<div style="margin: auto;"> 3251 <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> 3252</div> 3253 3254<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> 3255 3256<p>Convolve the image with a Gaussian or normal distribution. The formula is:</p> 3257 3258<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="/images/gaussian-blur.png"/> 3259</div> 3260 3261<p>where <i>r</i> is the blur radius (<i>r</i><sup>2</sup> = <i>u</i><sup>2</sup> + <i>v</i><sup>2</sup>), and σ is the standard deviation of the Gaussian distribution. As a guideline, set <i>r</i> to approximately 3σ. Specify a radius of 0 and ImageMagick selects a suitable radius for you.</p> 3262 3263<p>This differs from the faster <a href="#blur">-blur</a> operator in that a 3264full 2-dimentional convolution is used to generate the weighted average of the 3265neighbouring pixels. </p> 3266 3267<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 3268pixels which are outside the image proper are blurred into the final result. 3269</p> 3270 3271 3272<div style="margin: auto;"> 3273 <h4><a name="geometry" id="geometry"></a>-geometry <em class="arg">geometry</em></h4> 3274</div> 3275 3276<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> 3277 3278<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> 3279 3280<div style="margin: auto;"> 3281 <h4><a name="gravity" id="gravity"></a>-gravity <em class="arg">type</em></h4> 3282</div> 3283 3284<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> 3285 3286<p>Choices include: <kbd>NorthWest</kbd>, <kbd>North</kbd>, <kbd>NorthEast</kbd>, 3287<kbd>West</kbd>, <kbd>Center</kbd>, <kbd>East</kbd>, <kbd>SouthWest</kbd>, 3288<kbd>South</kbd>, <kbd>SouthEast</kbd>. Use <a href="#list">-list gravity</a> to get a complete 3289list of <a href="#gravity">-gravity</a> settings available in your ImageMagick 3290installation.</p> 3291 3292<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> 3293 3294<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> 3295 3296<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> 3297 3298<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -gravity Center -region 10x10-40+20 -negate output.png</span></p> 3299<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> 3300 3301<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> 3302 3303 3304<div style="margin: auto;"> 3305 <h4><a name="green-primary" id="green-primary"></a>-green-primary <em class="arg">x,y</em></h4> 3306</div> 3307 3308<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> 3309 3310 3311<div style="margin: auto;"> 3312 <h4><a name="hald-clut" id="hald-clut"></a>-hald-clut</h4> 3313</div> 3314 3315<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> 3316 3317<p>A Hald color lookup table is a 3-dimensional color cube mapped to 2 3318dimensions. Create it with the <kbd>HALD:</kbd> prefix (e.g. HALD:8). You 3319can apply any color transformation to the Hald image and then use this option 3320to apply the transform to the image. </p> 3321 3322<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png hald.png -hald-clut transform.png</span></p> 3323<p>This option provides a convenient method for you to use Gimp or Photoshop 3324to make color corrections to the Hald CLUT image and subsequently apply them 3325to multiple images using an ImageMagick script. </p> 3326 3327<p>Note that the representation is only of the normal RGB color space and that 3328the whole color value triplet is used for the interpolated lookup of the 3329represented Hald color cube image. Because of this the operation is not <a 3330href="#channel" >-channel</a> setting effected, nor can it adjust or modify an 3331images transparency or alpha/matte channel.</p> 3332 3333<p>See also <a href="#clut" >-clut</a> which provides color value replacement 3334of the individual color channels, usally involving a simplier gray-scale 3335image. E.g: gray-scale to color replacement, or modification by a histogram 3336mapping. </p> 3337 3338 3339<div style="margin: auto;"> 3340 <h4><a name="help" id="help"></a>-help</h4> 3341</div> 3342 3343<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> 3344 3345<div style="margin: auto;"> 3346 <h4><a name="highlight-color" id="highlight-color"></a>-highlight-color <em class="arg">color</em></h4> 3347</div> 3348 3349<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> 3350 3351<div style="margin: auto;"> 3352 <h4><a name="iconGeometry" id="iconGeometry"></a>-iconGeometry <em class="arg">geometry</em></h4> 3353</div> 3354 3355<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> 3356 3357<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> 3358 3359<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> 3360 3361<div style="margin: auto;"> 3362 <h4><a name="iconic" id="iconic"></a>-iconic</h4> 3363</div> 3364 3365<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> 3366 3367<div style="margin: auto;"> 3368 <h4><a name="identify" id="identify"></a>-identify</h4> 3369</div> 3370 3371<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> 3372 3373<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> 3374 3375<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> 3376 3377<p>If <a href="#verbose">-verbose</a> preceds this option, copious 3378amounts of image properties are displayed including image statistics, profiles, 3379image histogram, and others.</p> 3380 3381<div style="margin: auto;"> 3382 <h4><a name="ift" id="ift"></a>-ift</h4> 3383</div> 3384 3385<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> 3386 3387<p>This option is new as of ImageMagick 6.5.4-3 and 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> 3388 3389<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> 3390 3391<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert fft_image.miff -ift fft_image_ift.png</span></p> 3392<p>or</p> 3393 3394<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> 3395 3396<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 will be at the right and/or bottom sides of the image. 3397 3398<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#ift">-ift</a>. 3399 3400<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. 3401 3402<div style="margin: auto;"> 3403 <h4><a name="immutable" id="immutable"></a>-immutable</h4> 3404</div> 3405 3406<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> 3407 3408<div style="margin: auto;"> 3409 <h4><a name="implode" id="implode"></a>-implode <em class="arg">factor</em></h4> 3410</div> 3411 3412<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> 3413 3414<div style="margin: auto;"> 3415 <h4><a name="insert" id="insert"></a>-insert <em class="arg">index</em></h4> 3416</div> 3417 3418<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> 3419 3420<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> 3421 3422<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> 3423 3424<div style="margin: auto;"> 3425 <h4><a name="intent" id="intent"></a>-intent <em class="arg">type</em></h4> 3426</div> 3427 3428<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> 3429 3430<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> 3431 3432<p>The default intent is undefined.</p> 3433 3434<p>To print a complete list of rendering intents, use <a href="#list">-list intent</a>.</p> 3435 3436<div style="margin: auto;"> 3437 <h4><a name="interlace" id="interlace"></a>-interlace <em class="arg">type</em></h4> 3438</div> 3439 3440<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> 3441 3442<p>Choose from:</p> 3443 3444<pre class="text"> 3445 none 3446 line 3447 plane 3448 partition 3449 JPEG 3450 GIF 3451 PNG 3452</pre> 3453 3454<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> 3455 3456<p><kbd>None</kbd> means do not interlace (RGBRGBRGBRGBRGBRGB...),</p> 3457 3458<p><kbd>Line</kbd> uses scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...), and.</p> 3459 3460<p><kbd>Plane</kbd> uses plane interlacing (RRRRRR...GGGGGG...BBBBBB...).</p> 3461 3462<p><kbd>Partition</kbd> is like plane except the different planes are saved to individual files (e.g. image.R, 3463image.G, and image.B).</p> 3464 3465<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> 3466image.</p> 3467 3468<p>To print a complete list of interlacing schemes, use <a href="#list">-list interlace</a>.</p> 3469 3470<div style="margin: auto;"> 3471 <h4><a name="interpolate" id="interpolate"></a>-interpolate <em class="arg">type</em></h4> 3472</div> 3473 3474<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> 3475 3476<p>When looking up the color of a pixel using a non-interger floating point 3477value, you typically fall in between the pixel colors defined by the source 3478image. This setting determines how the color is determined from the colors of 3479the pixels surrounding that point. That is how to determine the color of a 3480point that falls between two, or even four different colored pixels. </p> 3481 3482<pre class="text"> 3483 integer: The color of the top-left pixel (floor function) 3484 nearest-neighbor: The nearest pixel to the lookup point (rounded function) 3485 average: The average color of the surrounding four pixels 3486 bilinear A double linear interpolation of pixels (the default) 3487 mesh Divide area into two flat triangular interpolations 3488 bicubic Fitted bicubic-spines of surrounding 16 pixels 3489 spline Direct spline curves (colors are blurred) 3490 filter Use resize <a href="#filter">-filter</a> settings 3491</pre> 3492 3493<p>This most important for distortion operators such as <a href="#distort" 3494>-distort</a>, <a href="#implode" >-implode</a>, <a href="#transform" 3495>-transform</a> and <a href="#fx" >-fx</a>. </p> 3496 3497<p>To print a complete list of interpolation methods, use <a href="#list">-list interpolate</a>.</p> 3498 3499<p>See also <a href="#virtual-pixel" >-virtual-pixel</a>, for control of the 3500lookup for positions outside the boundaries of the image. </p> 3501 3502 3503<div style="margin: auto;"> 3504 <h4><a name="interline-spacing" id="interline-spacing"></a>-interline-spacing <em class="arg">value</em></h4> 3505</div> 3506 3507<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> 3508 3509<div style="margin: auto;"> 3510 <h4><a name="interword-spacing" id="interword-spacing"></a>-interword-spacing <em class="arg">value</em></h4> 3511</div> 3512 3513<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> 3514 3515<div style="margin: auto;"> 3516 <h4><a name="kerning" id="kerning"></a>-kerning <em class="arg">value</em></h4> 3517</div> 3518 3519<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> 3520 3521<div style="margin: auto;"> 3522 <h4><a name="label" id="label"></a>-label <em class="arg">name</em></h4> 3523</div> 3524 3525<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> 3526 3527<p>Use this option to assign a specific label to the image, as it is read in or created. You can use the <a href="#set" >-set</a> operation to re-assign a the labels of images already read in. Image formats such as TIFF, PNG, MIFF, supports saving the label information with the image.</p> 3528 3529<p>When saving an image to a <em class="arg">PostScript</em> file, any label assigned to an image is used as a header string to print above the postscript image. </p> 3530 3531<p>You can include the image filename, type, width, height, or other image attribute by embedding special format character. See <a href="#format">-format</a> for details of the percent escape codes.</p> 3532 3533<p>For example,</p> 3534 3535<p class="crtsnip"> 3536 -label "%m:%f %wx%h" bird.miff 3537</p> 3538 3539<p>assigns an image label of <kbd>MIFF:bird.miff 512x480</kbd> to the "<kbd>bird.miff</kbd>" image and whose width is 512 and height is 480, as it is read in. If a <a href="#label">+label</a> option was used instead, any existing label present in the image would be used. You can remove all labels from an image by assigning the empty string. </p> 3540 3541<p>A label is not drawn on the image, but is embedded in the image datastream via <em>Label</em> tag or similar mechanism. If you want the label to be visible on the image itself, use the <a href="#draw">-draw</a> option, or during the final processing in the creation of a image montage.</p> 3542 3543<p>The label font can be specified with <a href="#font">-font</a>, and the 3544other font attribute settings.</p> 3545 3546<p>If the first character of <em class="arg">string</em> is <em class="arg">@</em>, the image label is read from a file titled by the remaining characters in the string. Labels in a file are literal, no embedded formatting characters are recognized.</p> 3547 3548 3549<div style="margin: auto;"> 3550 <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> 3551</div> 3552 3553<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> 3554 3555<p>Adaptively threshold each pixel based on the value of pixels in a 3556surrounding window. If the current pixel is lighter than this average plus 3557the optional <kbd>offset</kbd>, then it is made white, otherwise it is made 3558black. Small variations in pixel values such as found in scanned documents 3559can be ignored if offset is positive. A negative offset will make it more 3560sensitive to those small variations. </p> 3561 3562<p>This is commonly used to threshold images with an uneven background. It is 3563based on the assumption that average color of the small window is the 3564the local background color, from which to separate the forground color. </p> 3565 3566 3567<div style="margin: auto;"> 3568 <h4><a name="layers" id="layers"></a>-layers <em class="arg">method</em></h4> 3569</div> 3570 3571<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> 3572 3573<p>Perform various image operation methods to a ordered sequence of images 3574which may represent either a set of overlaid 'image layers', a GIF disposal 3575animation, or a fully-'coalesced' animation sequence. </p> 3576 3577<table class="doc"> 3578 <tbody> 3579 <tr valign="top"> 3580 <th align="left" style="width: 8%">Method</th> 3581 <th align="left">Description</th> 3582 </tr> 3583 3584 <tr valign="top"> 3585 <td valign="top">compare-any</td> 3586 <td valign="top">Crop the second and later frames to the smallest rectangle 3587 that contains all the differences between the two images. No GIF <a 3588 href="#dispose" >-dispose</a> methods are taken into account. </td> 3589 </tr> 3590 3591 <tr><td></td><td>This exactly the same as the <a href="#deconstruct" 3592 >-deconstruct</a> operator, and does not preserve animations normal 3593 working, especially when animation used layer disposal methods such as 3594 '<kbd>Previous</kbd>' or '<kbd>Background</kbd>'. </td> 3595 </tr> 3596 3597 <tr valign="top"> 3598 <td valign="top">compare-clear</td> 3599 <td valign="top">As '<kbd>compare-any</kbd>' but crop to the bounds of any 3600 opaque pixels which become transparent in the second frame. That is the 3601 smallest image needed to mask or erase pixels for the next frame. </td> 3602 </tr> 3603 3604 <tr valign="top"> 3605 <td valign="top">compare-overlay</td> 3606 <td valign="top">As '<kbd>compare-any</kbd>' but crop to pixels that add 3607 extra color to the next image, as a result of overlaying color pixels. 3608 That is the smallest single overlaid image to add or change colors. </td> 3609 </tr> 3610 3611 <tr><td></td><td>This can be used with the <a href="#compose" >-compose</a> alpha 3612 composition method '<kbd>change-mask</kbd>', to reduce the image to 3613 just the pixels that need to be overlaid. </td> 3614 </tr> 3615 3616 <tr valign="top"> 3617 <td valign="top">coalesce</td> 3618 <td valign="top">Equivalent to a call to the <a href="#coalesce" 3619 >-coalesce</a> operator. Apply the layer disposal methods set in the 3620 current image sequence to form a fully defined animation sequence, as 3621 it should be displayed. Effectively converting a GIF animation into a 3622 'film strip'-like animation. </td> 3623 </tr> 3624 3625 <tr valign="top"> 3626 <td valign="top">composite</td> 3627 <td valign="top">Alpha Composition of two image lists, separated by a 3628 "<kbd>null:</kbd>" image, with the destination image list first, and 3629 the source images last. An image from each list are composited 3630 together until one list is finished. The separator image and source 3631 image lists are removed. </td> 3632 </tr> 3633 3634 3635 <tr><td></td><td>The <a href="#geometry" >-geometry</a> offset is adjusted according to 3636 <a href="#gravity" >-gravity</a> in accordance of the virtual canvas 3637 size of the first image in each list. Unlike a normal <a 3638 href="#composite" >-composite</a> operation, the canvas offset is also 3639 added to the final composite positioning of each image. </td> 3640 </tr> 3641 3642 <tr><td></td><td>If one of the image lists only contains one image, that image is 3643 applied to all the images in the other image list, regardless of which 3644 list it is. In this case it is the image meta-data of the list which 3645 preserved. </td> 3646 </tr> 3647 3648 3649 <tr valign="top"> 3650 <td valign="top">dispose</td> 3651 <td valign="top">This like '<kbd>coalesce</kbd>' but shows the look of 3652 the animation after the layer disposal method has been applied, before 3653 the next sub-frame image is overlaid. That is the 'dispose' image that 3654 results from the application of the GIF <a href="#dispose" 3655 >-dispose</a> method. This allows you to check what 3656 is going wrong with a particular animation you may be developing. 3657 </td> 3658 </tr> 3659 3660 <tr valign="top"> 3661 <td valign="top">flatten</td> 3662 <td valign="top">Create a canvas the size of the first images virtual 3663 canvas using the current <a href="#background" >-background</a> color, 3664 and <a href="#compose" >-compose</a> each image in turn onto that 3665 canvas. Images falling outside that canvas is clipped. Final 3666 image will have a zero virtual canvas offset. </td> 3667 </tr> 3668 3669 <tr><td></td><td>This usally used as one of the final 'image layering' operations 3670 overlaying all the prepared image layers into a final image. </td> 3671 </tr> 3672 3673 <tr><td></td><td>For a single image this method can also be used to fillout a virtual 3674 canvas with real pixels, or to underlay a opaque color to remove 3675 transparency from an image.</td> 3676 </tr> 3677 3678 3679 <tr valign="top"> 3680 <td valign="top">merge</td> 3681 <td valign="top">As 'flatten' method but merging all the given image 3682 layers into a new layer image just large enough to hold all the image 3683 without clipping or extra space. The new images virtual offset will 3684 prevere the position of the new layer, even if this offset is 3685 negative. the virtual canvas size of the first image is preserved. 3686 </td> 3687 </tr> 3688 3689 <tr><td></td><td>Caution is advised when handling image layers with negative offsets 3690 as few image file formats handle them correctly. </td> 3691 </tr> 3692 3693 <tr valign="top"> 3694 <td valign="top">mosaic</td> 3695 <td valign="top">As 'flatten' method but expanding the initial canvas size 3696 of the first image so as to hold all the image layers. However as a 3697 virtual canvas is 'locked' to the origin, by defination, image layers 3698 with a negative offsets will still be clipped by the top and left 3699 edges.</td> 3700 </tr> 3701 3702 <tr><td></td><td>This method is commonly used to layout individual image using various 3703 offset but without knowning the final canvas size. The resulting image 3704 will, like 'flatten' not have any virtual offset, so can be saved to 3705 any image file format. </td> 3706 </tr> 3707 3708 3709 <tr valign="top"> 3710 <td valign="top">optimize</td> 3711 <td valign="top">Optimize a coalesced animation, into GIF animation using 3712 a number of general techniques. This currently a short cut to 3713 apply both the '<kbd>optimize-frame</kbd>', and 3714 '<kbd>optimize-transparency</kbd>' methods but may be expanded to 3715 include other optimization methods as they are developed. </td> 3716 </tr> 3717 3718 <tr valign="top"> 3719 <td valign="top">optimize-frame</td> 3720 <td valign="top">Optimize a coalesced animation, into GIF animation by 3721 reducing the number of pixels per frame as much as possible by 3722 attempting to pick the best layer disposal method to use, while ensuring 3723 the result will continue to animate properly. </td> 3724 </tr> 3725 3726 <tr><td></td><td> There is no guarantee that the best optimization is found. But 3727 then no reasonably fast GIF optimization algorithm can do this. 3728 However this does seem to do better than most other GIF frame 3729 optimizers seen. </td> 3730 </tr> 3731 3732 <tr valign="top"> 3733 <td valign="top">optimize-plus</td> 3734 <td valign="top">As '<kbd>optimize-frame</kbd>' but attempt to improve the 3735 overall optimization by adding extra frames to the animation, without 3736 changing the final look or timing of the animation. The frames are 3737 added to attempt to separate the clearing of pixels from the 3738 overlaying of new additional pixels from one animation frame to the 3739 next. If this does not improve the optimization (for the next frame 3740 only), it will fall back to the results of the previous normal 3741 '<kbd>optimize-frame</kbd>' technique. </td> 3742 </tr> 3743 3744 <tr><td></td><td>There is the possibility that the change in the disposal style will 3745 result in a worsening in the optimization of later frames, though this 3746 is unlikely. In other words there no guarantee that it is better than 3747 the normal '<kbd>optimize-frame</kbd>' technique. For some animations 3748 however you can get a vast improvment in the final animation size. </td> 3749 </tr> 3750 3751 <tr valign="top"> 3752 <td valign="top">optimize-transparency</td> 3753 <td valign="top">Given a GIF animation, replace any pixel in the sub-frame 3754 overlay images with transparency, if it does not change the resulting 3755 animation by more than the current <a href="#fuzz" >-fuzz</a> factor. 3756 </td> 3757 </tr> 3758 3759 <tr><td></td><td>This should allow a existing frame optimized GIF animation to compress 3760 into a smaller file size due to larger areas of one (transparent) 3761 color rather than a pattern of multiple colors repeating the current 3762 disposed image of the last frame. </td> 3763 </tr> 3764 3765 <tr valign="top"> 3766 <td valign="top">remove-dups</td> 3767 <td valign="top">Remove (and merge time delays) of duplicate consecutive 3768 images, so as to simplify layer overlays of coalesced animations. 3769 </td> 3770 </tr> 3771 3772 <tr><td></td><td>Usually this a result of using a constant time delay across the 3773 whole animation, or after a larger animation was split into smaller 3774 sub-animations. The duplicate frames could also have been used as 3775 part of some frame optimization methods. </td> 3776 </tr> 3777 3778 <tr valign="top"> 3779 <td valign="top">remove-zero</td> 3780 <td valign="top">Remove any image with a zero time delay, unless ALL the 3781 images have a zero time delay (and is not a proper timed animation, a 3782 warning is then issued). </td> 3783 </tr> 3784 3785 <tr><td></td><td>In a GIF animation, such images are usually frames which provide 3786 partial intermediary updates between the frames that are actually 3787 displayed to users. These frames are usally added for improved frame 3788 optimization in GIF animations. </td> 3789 </tr> 3790 3791 <tr valign="top"> 3792 <td valign="top">trim-bounds</td> 3793 <td valign="top">Find the bounds of all the images in the current 3794 image sequence, then adjust the offsets so all images are contained on 3795 a minimal positive canvas. None of the image data is modified, only 3796 there virtual canvas size and offset. The all the image is given 3797 the same canvas size, and and will have a positive offset, but will 3798 remain in the same position relative to each other. As a result of the 3799 minimal canvas size at least one image will touch every edge of that 3800 canvas. The image data however may be transparent. 3801 </td> 3802 </tr> 3803 3804 </tbody> 3805</table> 3806 3807<p>To print a complete list of layer types, use <a href="#list">-list layers</a>.</p> 3808 3809<p>The operators <a href="#coalesce" >-coalesce</a>, <a href="#deconstruct" 3810>-deconstruct</a>, <a href="#flatten" >-flatten</a>, and <a href="#mosaic" 3811>-mosaic</a> are only aliases for the above methods. Also see <a 3812href="#page" >-page</a>, <a href="#repage" >-repage</a> operators, the <a 3813href="#compose" >-compose</a> setting, and the GIF <a href="#dispose" 3814>-dispose</a> and <a href="#delay" >-delay</a> settings. </p> 3815 3816 3817<div style="margin: auto;"> 3818 <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> 3819</div> 3820 3821<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> 3822 3823<p>Given one, two or three values delimited with commas: black-point, 3824white-point, gamma (for example: 10,250,1.0 or 2%,98%,0.5). The black and 3825white points range from 0 to <em class="QR">QuantumRange</em>, or from 0 to 100%; if the white 3826point is omitted it is set to (<em class="QR">QuantumRange</em> - black_point), so as to center 3827contrast changes. If a <kbd>%</kbd> sign is present anywhere in the string, 3828both black and white points are percentages of the full color range. Gamma 3829will do a <a href="#gamma">-gamma</a> adjustment of the values. If it is 3830omitted, the default of 1.0 (no gamma correction) is assumed.</p> 3831 3832<p>In normal usage (<kbd>-level</kbd>) the image values are stretched so that 3833the given '<kbd>black_point</kbd>' value in the original image is set to 3834zero (or black), while the given '<kbd>white_point</kbd>' value is set to 3835<em class="QR">QuantumRange</em> (or white). This provides you with direct contrast adjustments 3836to the image. The '<kbd>gamma</kbd>' of the resulting image will then be 3837adjusted. </p> 3838 3839<p>From ImageMagick v6.4.1-9 using the plus form of the operator (<kbd>+level</kbd>) or 3840adding the special '!' flag anywhere in the argument list, will cause the 3841operator to do the reverse of the level adjustment. That is a zero, or 3842<em class="QR">QuantumRange</em> value (black, and white, resp.) in the original image, is 3843adjusted to the given level values, allowing you to de-contrast, or compress 3844the channel values within the image. The '<kbd>gamma</kbd>' is adjusted before the level adjustment to de-contrast the image is made. </p> 3845 3846<p>Only the channels defined by the current <a href="#channel">-channel</a> 3847setting are adjusted (defaults to RGB color channels only), allowing you to 3848limit the effect of this operator. </p> 3849 3850<p>Please note that the transparency channel is treated as 'matte' 3851values (0 is opaque) and not as 'alpha' values (0 is transparent).</p> 3852 3853 3854<div style="margin: auto;"> 3855 <h4><a name="level-colors" id="level-colors"></a>-level-colors {<em 3856 class="arg">black_color</em>}{,}{<em class="arg">white_color</em>}</h4> 3857</div> 3858 3859<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 seperated colors.</td><td style='text-align:right;'></td></tr></table> 3860 3861<p>This function is exactly like <a href="#level">-level</a>, except that the 3862value value for each color channel is determined by the 3863'<kbd>black_color</kbd>' and '<kbd>white_color</kbd>' colors given (as 3864described under the <a href="#fill">-fill</a> option). </p> 3865 3866<p>This effectivally means the colors provided to <kbd>-level-colors</kbd> 3867is mapped to become 'black' and 'white' respectivally, with all the other 3868colors linearly adjusted (or clipped) to match that change. Each channel is 3869adjusted separatally using the channel values of the colors specified. </p> 3870 3871<p>On the other hand the plus form of the operator (<kbd>+level-colors</kbd>) 3872will map the image color 'black' and 'white' to the given colors 3873respectivally, resulting in a gradient (de-contrasting) tint of the image to 3874those colors. This can also be used to convert a plain gray-scale image into a 3875one using the gradient of colors specified. </p> 3876 3877<p>By supplying a single color with a comma separator either before or after 3878that color, will just replace the respective 'black' or 'white' point 3879respectivally. But if no comma separator is provided, the given color is 3880used for both the black and white color points, making the operator either 3881threshold the images around that color (- form) or set all colors to that 3882color (+ form). </p> 3883 3884 3885<div style="margin: auto;"> 3886 <h4><a name="limit" id="limit"></a>-limit <em class="arg">type value</em></h4> 3887</div> 3888 3889<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> 3890 3891<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> 3892 3893<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> 3894 3895<p class="crtsnip"> 3896 -limit memory 32MiB -limit map 64MiB 3897</p> 3898 3899<p>Use <a href="#list">-list resource</a> to list the current limits. For example, our system shows these limits:</p> 3900 3901<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 3902------------------------------------------------------------------------------ 3903 768 12.404GB 8.6642GiB 23.104GiB 18.446744EB 8 unlimited</pre> 3904</span></p> 3905<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> 3906 3907<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> 3908 3909<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> 3910 3911<p class="crtsnip"> 3912-limit area 10mb 3913</p> 3914 3915<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 inadvertedly upload a huge image to process, you should set a disk limit as well:</p> 3916 3917<p class="crtsnip"> 3918-limit area 10mb -limit disk 500mb 3919</p> 3920 3921<p>Here ImageMagick stops processing if an image requires more than 500MB of disk storage.</p> 3922 3923<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> 3924 3925<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. 3926</p> 3927 3928<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. 3929</p> 3930 3931<div style="margin: auto;"> 3932 <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> 3933</div> 3934 3935<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> 3936 3937<p>This is very similar to <a href="#contrast-stretch" >-contrast-stretch</a>, 3938and uses a 'histogram bin' to determine the range of color values that needs to 3939be stretched. However it then stretchs those colors using the <a 3940href="#level" >-level</a> operator.</p> 3941 3942<p>As such while the initial determination may have 'binning' round off 3943effects, the image colors are stretched mathematically, rather than using the 3944histogram bins. This makes the operator more accurate. </p> 3945 3946<p>note however that a <a href="#linear-stretch" >-linear-stretch</a> of 3947'<kbd>0</kbd>' does nothing, while a value of '<kbd>1</kbd>' does a near 3948perfect stretch of the color range. </p> 3949 3950<p>See also <a href="#auto-level" >-auto-level</a> for a 'perfect' 3951normalization of mathematical images. </p> 3952 3953<p>This operator is under review for re-development. </p> 3954 3955 3956<div style="margin: auto;"> 3957 <h4><a name="linewidth" id="linewidth"></a>-linewidth</h4> 3958</div> 3959 3960<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> 3961 3962<div style="margin: auto;"> 3963 <h4><a name="liquid-rescale" id="liquid-rescale"></a>-liquid-rescale <em class="arg">geometry</em></h4> 3964</div> 3965 3966<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> 3967 3968<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> 3969 3970<div style="margin: auto;"> 3971 <h4><a name="list" id="list"></a>-list <em class="arg">type</em></h4> 3972</div> 3973 3974<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> 3975 3976<pre class="text"> 3977 coder 3978 color 3979 configure 3980 delegate 3981 font 3982 format 3983 list 3984 log 3985 magic 3986 module 3987 resource 3988 threshold 3989</pre> 3990 3991<p>The above lists are only some of the many lists available. These lists vary depending on your version of ImageMagick. For example use "<kbd>-list list</kbd>" to get a complete listing of all the "<kbd>-list</kbd>" arguments available:</p> 3992 3993<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>identify -list list</span></p> 3994<div style="margin: auto;"> 3995 <h4><a name="log" id="log"></a>-log <em class="arg">string</em></h4> 3996</div> 3997 3998<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> 3999 4000<p>This option specifies the format for the log printed when the <a href="#debug">-debug</a> option is active.</p> 4001 4002<p>You can display the following components by embedding special format characters:</p> 4003 4004<pre class="text"> 4005 %d domain 4006 %e event 4007 %f function 4008 %l line 4009 %m module 4010 %p process ID 4011 %r real CPU time 4012 %t wall clock time 4013 %u user CPU time 4014 %% percent sign 4015 \n newline 4016 \r carriage return 4017</pre> 4018 4019<p>For example:</p> 4020 4021<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> 4022<p>The default behavior is to print all of the components.</p> 4023 4024<div style="margin: auto;"> 4025 <h4><a name="loop" id="loop"></a>-loop <em class="arg">iterations</em></h4> 4026</div> 4027 4028<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> 4029 4030<p>Set iterations to zero to repeat the animation an infinite number of times, otherwise the animation repeats itself up to <em class="arg">iterations</em> times.</p> 4031 4032<div style="margin: auto;"> 4033 <h4><a name="lowlight-color" id="lowlight-color"></a>-lowlight-color <em class="arg">color</em></h4> 4034</div> 4035 4036<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> 4037 4038<div style="margin: auto;"> 4039 <h4><a name="magnify" id="magnify"></a>-magnify <em class="arg">factor</em></h4> 4040</div> 4041 4042<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> 4043 4044 4045<div style="margin: auto;"> 4046 <h4><a name="map" id="map"></a>-map <em class="arg">type</em></h4> 4047</div> 4048 4049<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> 4050 4051<p>Choose from these <em class="arg">Standard Colormap</em> types:</p> 4052 4053<pre class="text"> 4054 best 4055 default 4056 gray 4057 red 4058 green 4059 blue 4060</pre> 4061 4062<p>The <em class="arg">X server</em> must support the <em class="arg">Standard Colormap</em> you choose, otherwise an error occurs. Use <kbd>list</kbd> as the type and <kbd>display</kbd> searches the list of colormap types in <kbd>top-to-bottom</kbd> order until one is located. See <em class="arg">xstdcmap(1)</em> for one way of creating Standard Colormaps.</p> 4063 4064 4065<div style="margin: auto;"> 4066 <h4><a name="map_stream_" id="map_stream_"></a>-map <em class="arg">components</em></h4> 4067</div> 4068 4069<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> 4070 4071<p>Here are the valid components of a map:</p> 4072 4073<pre class="text"> 4074 r red pixel component 4075 g green pixel component 4076 b blue pixel component 4077 a alpha pixel component (0 is transparent) 4078 o opacity pixel component (0 is opaque) 4079 i grayscale intensity pixel component 4080 c cyan pixel component 4081 m magenta pixel component 4082 y yellow pixel component 4083 k black pixel component 4084 p pad component (always 0) 4085</pre> 4086 4087<p>You can specify as many of these components as needed in any order (e.g. bgr). The components can repeat as well (e.g. rgbr).</p> 4088 4089<div style="margin: auto;"> 4090 <h4><a name="mask" id="mask"></a>-mask 4091<em class="arg">filename</em></h4> 4092</div> 4093 4094<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> 4095 4096<p>Use <a href="#mask">+mask</a> to remove the image mask.</p> 4097 4098<div style="margin: auto;"> 4099 <h4><a name="mattecolor" id="mattecolor"></a>-mattecolor <em class="arg">color</em></h4> 4100</div> 4101 4102<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> 4103 4104<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 4105 4106<p>The default matte color is <kbd>#BDBDBD</kbd>, <span style="background-color: #bdbdbd;">this shade of gray</span>.</p> 4107 4108<div style="margin: auto;"> 4109 <h4><a name="median" id="median"></a>-median <em class="arg">radius</em></h4> 4110</div> 4111 4112<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> 4113 4114<div style="margin: auto;"> 4115 <h4><a name="metric" id="metric"></a>-metric <em class="arg">type</em></h4> 4116</div> 4117 4118<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> 4119 4120<p>Choose from:</p> 4121 4122<pre class="text"> 4123 AE absolute number of differnet pixels 4124 MAE mean absolute error (normalized), average channel error distance 4125 MEPP mean error per pixel (normalized mean error, normalized peak error) 4126 MSE mean error squared, average of the channel error squared 4127 PAE peak absolute (normalize peak absolute) 4128 PSNR peak signal to noise ratio 4129 RMSE root mean squared (normalized root mean squared) 4130</pre> 4131 4132<p>The '<kbd>AE</kbd>' or absolute count of pixels that are different, can be 4133controled using a <a href="#fuzz" >-fuzz</a> factor to ignore pixels which 4134only changed by a small amount. The '<kbd>PAE</kbd>' can be used to find the 4135size of the <a href="#fuzz" >-fuzz</a> factor needed to make all pixels 4136'similar'. </p> 4137 4138<p>The '<kbd>MEPP</kbd>' metric returns three different metrics 4139('<kbd>MAE</kbd>', '<kbd>MAE</kbd>' normalized, and '<kbd>PAE</kbd>' 4140normalized) from the single comparision run. </p> 4141 4142<p>To print a complete list of metrics, use the <a href="#list">-list metrics</a> option.</p> 4143 4144 4145<div style="margin: auto;"> 4146 <h4><a name="mode" id="mode"></a>-mode <em class="arg">value</em></h4> 4147</div> 4148 4149<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> 4150 4151<p>Choose the <em class="arg">value</em> from these styles: <kbd>Frame, Unframe, or Concatenate</kbd></p> 4152 4153<p>Use the <a href="#list" >-list</a> option with a '<kbd>Mode</kbd>' 4154argument for a list of <a href="#mode" >-mode</a> arguments available 4155in your ImageMagick installation.</p> 4156 4157 4158<div style="margin: auto;"> 4159 <h4><a name="modulate" id="modulate"></a>-modulate <em class="arg">brightness</em>[,<em class="arg">saturation</em>,<em class="arg">hue</em>]</h4> 4160</div> 4161 4162<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 class="arg">saturation</em>, and <em class="arg">hue</em> of an image.</td><td style='text-align:right;'></td></tr></table> 4163 4164<p>The arguments are given as a percentages of variation. A value of 100 means no change, and any 4165missing values are taken to mean 100.</p> 4166 4167<p>The <em class="arg">brightness</em> is a multiplier of the overall brightness of the image, so 0 4168means pure black, 50 is half as bright, 200 is twice as bright. To invert its 4169meaning <a href="#negate">-negate</a> the image before and after. </p> 4170 4171<p>The <em class="arg">saturation</em> controls the amount of color in an image. For example, 0 produce a grayscale image, while a large value such as 200 produce a very colorful, 'cartoonish' color.</p> 4172 4173<p>The <em class="arg">hue</em> argument causes a "rotation" of the colors within the image by the amount specified. For example, 50 results in a counter-clockwise rotation of 90, mapping red 4174shades to purple, and so on. A value of either 0 or 200 results in a complete 4175180 degree rotation of the image. Using a value of 300 is a 360 degree 4176rotation resulting in no change to the original image. </p> 4177 4178<p>For example, to increase the color brightness by 20% and decrease the color saturation by 10% and leave the hue unchanged, use <a href="#modulate">-modulate 120,90</a>.</p> 4179 4180<p>Use <a href="#set">-set</a> attribute of '<kbd class="arg">option:modulate:colorspace</kbd>' to specify which colorspace to modulate. Choose from <kbd>HSB</kbd>, <kbd>HSL</kbd> (the default), or <kbd>HWB</kbd>. For example,</p> 4181 4182<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> 4183<div style="margin: auto;"> 4184 <h4><a name="monitor" id="monitor"></a>-monitor</h4> 4185</div> 4186 4187<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> 4188 4189 4190<div style="margin: auto;"> 4191 <h4><a name="monochrome" id="monochrome"></a>-monochrome</h4> 4192</div> 4193 4194<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> 4195 4196 4197<div style="margin: auto;"> 4198 <h4><a name="morph" id="morph"></a>-morph <em class="arg">frames</em></h4> 4199</div> 4200 4201<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> 4202 4203<p>Both the image pixels and size are linearly interpolated to give the 4204appearance of a meta-morphosis from one image to the next, over all the images 4205in the current image list. The added images are the equivalent of a <a 4206href="#blend">-blend</a> composition. The <em class="arg">frames</em> 4207argument determine how many images to interpolate between each image. </p> 4208 4209 4210<div style="margin: auto;"> 4211 <h4><a name="morphology" id="morphology"></a>-morphology</h4> 4212 <h4><a name="morphology" id="morphology"></a>-morphology <em class="arg">method</em> <em class="arg">kernel</em></h4> 4213</div> 4214 4215<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> 4216 4217<div style="margin: auto;"> 4218 <h4><a name="mosaic" id="mosaic"></a>-mosaic</h4> 4219</div> 4220 4221<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> 4222 4223 4224<div style="margin: auto;"> 4225 <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> 4226</div> 4227 4228<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> 4229 4230<p>Blur with the given radius, standard deviation (sigma), and angle. The 4231angle given is the angle toward which the image is blurred. That is the 4232direction people would consider the object is coming from. </p> 4233 4234<p>Note that the blur is not uniform distribution, giving the motion a 4235definate sense of direction of movement. </p> 4236 4237<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 4238pixels which are outside the image proper are blurred into the final result. 4239</p> 4240 4241<div style="margin: auto;"> 4242 <h4><a name="name" id="name"></a>-name</h4> 4243</div> 4244 4245<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> 4246<div style="margin: auto;"> 4247 <h4><a name="negate" id="negate"></a>-negate</h4> 4248</div> 4249 4250<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> 4251 4252<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> 4253 4254<div style="margin: auto;"> 4255 <h4><a name="noise" id="noise"></a>-noise <em class="arg">radius</em><br/> 4256 +noise <em class="arg">type</em></h4> 4257</div> 4258 4259<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> 4260 4261<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> 4262 4263<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> 4264 4265<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> 4266 4267<pre class="text"> 4268Gaussian 4269Impulse 4270Laplacian 4271Multiplicative 4272Poisson 4273Random 4274Uniform 4275</pre> 4276 4277<p>To print a complete list of noises, use the <a href="#list">-list noise</a> option.</p> 4278 4279<p>Also see the <a href="#evaluate">-evaluate</a> noise functions that allos 4280the use of a controlling value to specify teh amount of noise that should be 4281added to an image. </p> 4282 4283 4284<div style="margin: auto;"> 4285 <h4><a name="normalize" id="normalize"></a>-normalize</h4> 4286</div> 4287 4288<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> 4289 4290<p>The intensity values are stretched to cover the entire range of possible 4291values. While doing so, black-out at most <em>2%</em> of the pixels and 4292white-out at most <em>1%</em> of the pixels.</p> 4293 4294<p>Note that as of ImageMagick 6.4.7-0, <a href="#normalize" >-normalize</a> 4295is equivalent to <a href="#contrast-stretch" >-contrast-stretch 2%x1%</a>. 4296(Before this version, it was equivalent to <a href="#contrast-stretch" 4297>-contrast-stretch 2%x99%</a>).</p> 4298 4299<p>All the channels are normalized in concert by the came amount so as to 4300preserve color integrity, when the default <a href="#channel" >+channel</a> 4301setting is in use. Specifing any other <a href="#channel" >-channel</a> 4302setting will normalize the RGB channels independently.</p> 4303 4304<p>See <a href="#contrast-stretch" >-contrast-stretch</A> for more details. 4305Also see <a href="#auto-level" >-auto-level</a> for a 'perfect' normalization 4306that is better suited to mathematically generated images. </p> 4307 4308<p>This operator is under review for re-development. </p> 4309 4310 4311<div style="margin: auto;"> 4312 <h4><a name="ordered-dither" id="ordered-dither"></a>-ordered-dither <em class="arg">threshold_map</em>{,<em class="arg">level</em>...}</h4> 4313</div> 4314 4315<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 4316class="arg">threshold map</em> specified, and a uniform color map with the 4317given number of <em class="arg">levels</em> per color channel . </td><td style='text-align:right;'></td></tr></table> 4318 4319<p>You can choose from these standard threshold maps:</p> 4320 4321<pre class="text"> 4322 threshold 4323 checks 4324 o2x2 4325 o3x3 4326 o4x4 4327 o8x8 4328 h4x4a 4329 h6x6a 4330 h8x8a 4331 h4x4o 4332 h6x6o 4333 h8x8o 4334 h16x16o 4335</pre> 4336 4337<p>The '<kbd>o</kbd>' maps are ordered diffused pixel threshold maps, while the 4338'<kbd>h</kbd>' maps are halftone threshold maps which are either 'a' angled, or 4339'o' orthogonal. The '<kbd>checks</kbd>' produce a 3 level checkerbord dither 4340pattern. Or you can define your own <em class="arg" >threshold map</em> in a 4341personal or system "<kbd>thresholds.xml</kbd>" XML file. </p> 4342 4343<p>To print a complete list of threshold, use the <a href="#list" >-list 4344threshold</a> option.</p> 4345 4346<p>It is recommended that the <a href="#map" >+map</a> operator be used after 4347applying <a href="#ordered-dither" >-ordered-dither</a> to reduce the number of 4348colors an animated image sequence, to less that 256 colors. This ensures that 4349a common or global color table is used when saving the result to a color 4350limited file format such as GIF. </p> 4351 4352<p>Note that at this time the exact same threshold dithering map is used for 4353all color channels, no attempt is made to offset or rotate the map for 4354different channels is made, to create an offset printing effect. (possible 4355future expansion) </p> 4356 4357 4358<div style="margin: auto;"> 4359 <h4><a name="opaque" id="opaque"></a>-opaque <em class="arg">color</em></h4> 4360</div> 4361 4362<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> 4363 4364<p>The <em class="arg">color</em> argument is defined using the format 4365described under the <a href="#fill" >-fill</a> option. The <a href="#fuzz" 4366>-fuzz</a> setting can be used to match and replace colors similar to the one 4367given.</p> 4368 4369<p>The <a href="#transparent" >-transparent</a> operator is exactly the same 4370as <a href="#opaque" >-opaque</a> but makes the matching color transparent, 4371rather than the same as the current <a href="#fill">-fill</a> color. </p> 4372 4373<p>Use <a href="#opaque">+opaque</a> to paint any pixel that does not match the target color.</p> 4374 4375 4376 4377<div style="margin: auto;"> 4378 <h4><a name="orient" id="orient"></a>-orient <em class="arg">image orientation</em></h4> 4379</div> 4380 4381<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> 4382 4383<p>Choose from these orientations:</p> 4384 4385<pre class="text"> 4386 bottom-left 4387 bottom-right 4388 left-bottom 4389 left-top 4390 right-bottom 4391 right-top 4392 top-left 4393 top-right 4394 undefined 4395</pre> 4396 4397<p>To print a complete list of orientations, use the <a href="#list" >-list 4398orientation</a> option.</p> 4399 4400 4401<div style="margin: auto;"> 4402 <h4><a name="page" id="page"></a>-page <em class="arg">geometry</em><br/> 4403 -page <em class="arg">media</em>[<em class="arg">offset</em>][{<em class="arg">^!<></em>}]<br/> 4404 +page 4405 </h4> 4406</div> 4407 4408<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> 4409 4410<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> 4411 4412<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> 4413 4414<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> 4415<table id="geometryTable" cellpadding="2" cellspacing="0" border="1" width="50%" style="margin-left: auto; margin-right: auto;"> 4416<thead> 4417 <tr valign="top"> 4418 <th align="center"><em class="arg">media</em></th> 4419 <th align="center"><em class="arg">width</em></th> 4420 <th align="center"><em class="arg">height</em></th> 4421 </tr> 4422</thead> 4423<tbody> 4424<tr><td align="left"> 11x17 </td> <td align="right"> 792</td> <td align="right"> 1224</td> </tr> 4425<tr><td align="left"> Ledger </td> <td align="right"> 1224</td> <td align="right"> 792</td> </tr> 4426<tr><td align="left"> Legal </td> <td align="right"> 612</td> <td align="right"> 1008</td> </tr> 4427<tr><td align="left"> Letter </td> <td align="right"> 612</td> <td align="right"> 792</td> </tr> 4428<tr><td align="left"> LetterSmall</td> <td align="right"> 612</td> <td align="right"> 792</td> </tr> 4429<tr><td align="left"> ArchE </td> <td align="right"> 2592</td> <td align="right"> 3456</td> </tr> 4430<tr><td align="left"> ArchD </td> <td align="right"> 1728</td> <td align="right"> 2592</td> </tr> 4431<tr><td align="left"> ArchC </td> <td align="right"> 1296</td> <td align="right"> 1728</td> </tr> 4432<tr><td align="left"> ArchB </td> <td align="right"> 864</td> <td align="right"> 1296</td> </tr> 4433<tr><td align="left"> ArchA </td> <td align="right"> 648</td> <td align="right"> 864</td> </tr> 4434<tr><td align="left"> A0 </td> <td align="right"> 2380</td> <td align="right"> 3368</td> </tr> 4435<tr><td align="left"> A1 </td> <td align="right"> 1684</td> <td align="right"> 2380</td> </tr> 4436<tr><td align="left"> A2 </td> <td align="right"> 1190</td> <td align="right"> 1684</td> </tr> 4437<tr><td align="left"> A3 </td> <td align="right"> 842</td> <td align="right"> 1190</td> </tr> 4438<tr><td align="left"> A4 </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr> 4439<tr><td align="left"> A4Small </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr> 4440<tr><td align="left"> A5 </td> <td align="right"> 421</td> <td align="right"> 595</td> </tr> 4441<tr><td align="left"> A6 </td> <td align="right"> 297</td> <td align="right"> 421</td> </tr> 4442<tr><td align="left"> A7 </td> <td align="right"> 210</td> <td align="right"> 297</td> </tr> 4443<tr><td align="left"> A8 </td> <td align="right"> 148</td> <td align="right"> 210</td> </tr> 4444<tr><td align="left"> A9 </td> <td align="right"> 105</td> <td align="right"> 148</td> </tr> 4445<tr><td align="left"> A10 </td> <td align="right"> 74</td> <td align="right"> 105</td> </tr> 4446<tr><td align="left"> B0 </td> <td align="right"> 2836</td> <td align="right"> 4008</td> </tr> 4447<tr><td align="left"> B1 </td> <td align="right"> 2004</td> <td align="right"> 2836</td> </tr> 4448<tr><td align="left"> B2 </td> <td align="right"> 1418</td> <td align="right"> 2004</td> </tr> 4449<tr><td align="left"> B3 </td> <td align="right"> 1002</td> <td align="right"> 1418</td> </tr> 4450<tr><td align="left"> B4 </td> <td align="right"> 709</td> <td align="right"> 1002</td> </tr> 4451<tr><td align="left"> B5 </td> <td align="right"> 501</td> <td align="right"> 709</td> </tr> 4452<tr><td align="left"> C0 </td> <td align="right"> 2600</td> <td align="right"> 3677</td> </tr> 4453<tr><td align="left"> C1 </td> <td align="right"> 1837</td> <td align="right"> 2600</td> </tr> 4454<tr><td align="left"> C2 </td> <td align="right"> 1298</td> <td align="right"> 1837</td> </tr> 4455<tr><td align="left"> C3 </td> <td align="right"> 918</td> <td align="right"> 1298</td> </tr> 4456<tr><td align="left"> C4 </td> <td align="right"> 649</td> <td align="right"> 918</td> </tr> 4457<tr><td align="left"> C5 </td> <td align="right"> 459</td> <td align="right"> 649</td> </tr> 4458<tr><td align="left"> C6 </td> <td align="right"> 323</td> <td align="right"> 459</td> </tr> 4459<tr><td align="left"> Flsa </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr> 4460<tr><td align="left"> Flse </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr> 4461<tr><td align="left"> HalfLetter </td> <td align="right"> 396</td> <td align="right"> 612</td> </tr> 4462</tbody> 4463</table> 4464 4465 4466 4467 4468<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> 4469 4470<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> 4471 4472<p>The default page dimensions for a TEXT image is 612x792.</p> 4473 4474<p>This option is used in concert with <a href="#density">-density</a>.</p> 4475 4476<p>Use <a href="#page">+page</a> to remove the page settings for an image.</p> 4477 4478<div style="margin: auto;"> 4479 <h4><a name="paint" id="paint"></a>-paint <em class="arg">radius</em></h4> 4480</div> 4481 4482<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> 4483 4484<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> 4485 4486<div style="margin: auto;"> 4487 <h4><a name="path" id="path"></a>-path <em class="arg">path</em></h4></div> 4488 4489<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> 4490 4491<div style="margin: auto;"> 4492 <h4><a name="pause_animate_" id="pause_animate_"></a>-pause <em class="arg">seconds</em></h4> 4493</div> 4494 4495<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> 4496 4497<p>Pause for the specified number of seconds before repeating the animation.</p> 4498 4499<div style="margin: auto;"> 4500 <h4><a name="pause_import_" id="pause_import_"></a>-pause <em class="arg">seconds</em></h4> 4501</div> 4502 4503<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> 4504 4505<p>Pause for the specified number of seconds before taking the next snapshot.</p> 4506 4507<div style="margin: auto;"> 4508 <h4><a name="ping" id="ping"></a>-ping</h4> 4509</div> 4510 4511<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> 4512 4513<div style="margin: auto;"> 4514 <h4><a name="pointsize" id="pointsize"></a>-pointsize <em class="arg">value</em></h4> 4515</div> 4516 4517<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> 4518 4519<div style="margin: auto;"> 4520 <h4><a name="polaroid" id="polaroid"></a>-polaroid <em class="arg">angle</em></h4> 4521</div> 4522 4523<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> 4524 4525<p>Use <kbd>+polaroid</kbd> to rotate the image at a random angle between -15 and +15 degrees.</p> 4526 4527<div style="margin: auto;"> 4528 <h4><a name="posterize" id="posterize"></a>-posterize <em class="arg">levels</em></h4> 4529</div> 4530 4531<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> 4532 4533<div style="margin: auto;"> 4534 <h4><a name="precision" id="precision"></a>-precision <em class="arg">value</em></h4> 4535</div> 4536 4537<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> 4538 4539<div style="margin: auto;"> 4540 <h4><a name="preview" id="preview"></a>-preview <em class="arg">type</em></h4> 4541</div> 4542 4543<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> 4544 4545<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> 4546 4547<pre class="text"> 4548 Rotate 4549 Shear 4550 Roll 4551 Hue 4552 Saturation 4553 Brightness 4554 Gamma 4555 Spiff 4556 Dull 4557 Grayscale 4558 Quantize 4559 Despeckle 4560 ReduceNoise 4561 Add Noise 4562 Sharpen 4563 Blur 4564 Threshold 4565 EdgeDetect 4566 Spread 4567 Shade 4568 Raise 4569 Segment 4570 Solarize 4571 Swirl 4572 Implode 4573 Wave 4574 OilPaint 4575 CharcoalDrawing 4576 JPEG 4577</pre> 4578 4579<p>To print a complete list of previews, use the <a href="#list">-list preview</a> option.</p> 4580 4581<p>The default preview is <kbd>JPEG</kbd>.</p> 4582 4583<div style="margin: auto;"> 4584 <h4><a name="print" id="print"></a>-print <em class="arg">string</em></h4> 4585</div> 4586 4587<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> 4588 4589<div style="margin: auto;"> 4590 <h4><a name="process" id="process"></a>-process <em class="arg">command</em></h4> 4591</div> 4592 4593<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> 4594 4595<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> 4596 4597<div style="margin: auto;"> 4598 <h4><a name="profile" id="profile"></a>-profile <em class="arg">filename</em><br/> 4599 +profile <em class="arg">profile_name</em></h4> 4600</div> 4601 4602<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> 4603 4604<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> 4605 4606<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> 4607 4608<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> 4609 4610<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> 4611 4612<p>For example, to extract the Exif data (which is stored in JPEG files in the <em class="arg">APP1</em> profile), use.</p> 4613 4614<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert cockatoo.jpg profile.exif</span></p> 4615<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> 4616 4617<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert CMYK.tif -profile "CMYK.icc" -profile "RGB.icc" RGB.tiff</span></p> 4618<p>Furthermore, since ICC profiles are not necessarily symmetric, extra conversion steps can yield unwanted results. 4619CMYK profiles are often very asymmetric since they involve 3−>4 and 4−>3 channel mapping. 4620</p> 4621 4622<div style="margin: auto;"> 4623 <h4><a name="quality" id="quality"></a>-quality <em class="arg">value</em></h4> 4624</div> 4625 4626<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> 4627 4628<p>For the JPEG and MPEG image formats, quality is 0 (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 85. Use the <a href="#sampling-factor">-sampling-factor</a> option to specify the factors for chroma downsampling.</p> 4629 4630<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> 4631 4632<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 85 results in a request for 16:1 compression. The quality value 100 results in a request for non-lossy compression.</p> 4633 4634<p>For the MNG and PNG image formats, the quality value sets the zlib compression level (quality / 10) and filter-type (quality % 10). Compression levels range from 0 (fastest compression) to 100 (best but slowest). For compression level 0, the Huffman-only strategy is used, which is fastest but not necessarily the worst compression.</p> 4635 4636<p>If filter-type is 4 or less, the specified filter-type is used for all scanlines:</p> 4637 4638<pre class="text"> 4639 0: none 4640 1: sub 4641 2: up 4642 3: average 4643 4: Paeth 4644</pre> 4645 4646<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> 4647 4648<p>If filter-type is 6, adaptive filtering with <em class="arg">minimum-sum-of-absolute-values</em> is used.</p> 4649 4650<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> 4651 4652<p>The default is quality is 85, which means nearly the best compression with adaptive filtering. The quality setting has no effect on the appearance of PNG and MNG images, since the compression is always lossless.</p> 4653 4654<p>For further information, see the <a href="http://www.w3.org/pub/WWW/TR">PNG</a> specification.</p> 4655 4656<p>When writing a JNG image with transparency, two quality values are required, one for the main image and one for the grayscale image that conveys the alpha channel. These are written as a single integer equal to the main image quality plus 1000 times the opacity quality. For example, if you want to use quality 85 for the main image and quality 90 to compress the opacity data, use <a href="#quality">-quality 90085</a>.</p> 4657 4658<div style="margin: auto;"> 4659 <h4><a name="quantize" id="quantize"></a>-quantize <em class="arg">colorspace</em></h4> 4660</div> 4661 4662<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>reduce colors in this colorspace.</td><td style='text-align:right;'></td></tr></table> 4663 4664<p>To print a complete list of colorspaces, use the <a href="#list">-list colorspace</a> option.</p> 4665 4666 4667<div style="margin: auto;"> 4668 <h4><a name="quiet" id="quiet"></a>-quiet</h4> 4669</div> 4670 4671<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> 4672 4673<div style="margin: auto;"> 4674 <h4><a name="radial-blur" id="radial-blur"></a>-radial-blur <em class="arg">angle</em></h4> 4675</div> 4676 4677<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> 4678 4679<p>Note that this is actually a rotational blur rather than a radial and as 4680such actually mis-named. </p> 4681 4682<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 4683pixels which are outside the image proper are blurred into the final result. 4684</p> 4685 4686 4687<div style="margin: auto;"> 4688 <h4><a name="raise" id="raise"></a>-raise <em class="arg">thickness</em></h4> 4689</div> 4690 4691<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> 4692 4693<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>. 4694</p> 4695 4696<p>Unlike the similar <a href="#frame">-frame</a> option, <a href="#raise">-raise</a> does not alter the dimensions of the image.</p> 4697 4698<div style="margin: auto;"> 4699 <h4><a name="random-threshold" id="random-threshold"></a>-random-threshold <em class="arg">low</em>x<em class="arg">high</em></h4> 4700</div> 4701 4702<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> 4703 4704<div style="margin: auto;"> 4705 <h4><a name="recolor" id="recolor"></a>-recolor <em class="arg">matrix</em></h4> 4706</div> 4707 4708<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Translate, scale, shear, or rotate image colors.</td><td style='text-align:right;'></td></tr></table> 4709 4710<p>Although variable-sized matrices can be used, typically one uses a 5x5 matrix for an RGBA image and a 6x6 for CMYKA. Populate the last row with normalized values to translate. The translation matrix is similar to that used by Adobe 4711Flash except that the offset is scaled to 1.0 (divide Flash offset by 255).</p> 4712 4713<div style="margin: auto;"> 4714 <h4><a name="red-primary" id="red-primary"></a>-red-primary <em class="arg">x,y</em></h4> 4715</div> 4716 4717<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> 4718 4719<div style="margin: auto;"> 4720 <h4><a name="regard-warnings" id="regard-warnings"></a>-regard-warnings</h4> 4721</div> 4722 4723<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> 4724 4725<div style="margin: auto;"> 4726 <h4><a name="remap" id="remap"></a>-remap <em class="arg">filename</em></h4> 4727</div> 4728 4729<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> 4730 4731<p>If the <a href="#dither">-dither</a> setting is enabled (the default) then 4732the given colors are dithered over the image as necessary, otherwise the closest 4733color (in RGB colorspace) is selected to replace that pixel in the image. </p> 4734 4735<p>As a side effect of applying a <a href="#remap">-remap</a> of colors across all 4736images in the current image sequence, all the images will have the same color 4737table. That means that when saved to a file format such as GIF, it will use 4738that color table as a single common or global color table, for all the images, 4739without requiring extra local color tables. </p> 4740 4741<p>Use <a href="#remap">+remap</a> to reduce all images in the current image 4742sequence to use a common color map over all the images. This equivalent to 4743appending all the images together (without extra background colors) and color 4744reducing those images using <a href="#colors">-colors</a> with a 256 color 4745limit, then <a href="#remap">-remap</a> those colors over the original list of 4746images. This ensures all the images follow a single color map. </p> 4747 4748<p>If the number of colors over all the images is less than 256, then <a 4749href="#remap">+remap</a> should not perform any color reduction or dithering, as 4750no color changes are needed. In that case, its only effect is to force the use 4751of a global color table. This recommended after using either <a 4752href="#colors">-colors</a> or <a href="#ordered-dither">-ordered-dither</a> to 4753reduce the number of colors in an animated image sequence. </p> 4754 4755<div style="margin: auto;"> 4756 <h4><a name="region" id="region"></a>-region <em class="arg">geometry</em></h4> 4757</div> 4758 4759<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> 4760 4761<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> 4762 4763<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> 4764 4765<div style="margin: auto;"> 4766 <h4><a name="remote" id="remote"></a>-remote</h4> 4767</div> 4768 4769<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> 4770 4771<p>The only command recognized is the name of an image file to load.</p> 4772 4773<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> 4774 4775<div style="margin: auto;"> 4776 <h4><a name="render" id="render"></a>-render</h4> 4777</div> 4778 4779<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> 4780 4781<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> 4782 4783<div style="margin: auto;"> 4784<h4><a name="repage" id="repage"></a>-repage <em class="arg">geometry</em></h4> 4785</div> 4786 4787<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> 4788 4789<p>This option is like <a href="#page">-page</a> but acts as an image operator 4790rather than a setting. You can separately set the canvas size or the offset 4791of the image on that canvas by only providing those components. </p> 4792 4793<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> 4794 4795<p>If a <kbd>!</kbd> flag is given the offset given is added to the existing 4796offset to move the image relative to its previous position. This useful for 4797animation sequences. </p> 4798 4799<p>A given a canvas size of zero such as '<kbd>0x0</kbd>' forces it to 4800recalculate the canvas size so the image (at its current offset) will appear 4801completely on that canvas (unless it has a negative offset).</p> 4802 4803<p>Use <a href="#repage">+repage</a> to completely remove/reset the virtual 4804canvas meta-data from the images. </p> 4805 4806<p>The <a href="#set">-set</a> '<kbd>page</kbd>' option can be used to 4807directly assign virtual canvas meta-data. </p> 4808 4809 4810<div style="margin: auto;"> 4811 <h4><a name="resample" id="resample"></a>-resample <em class="arg">horizontal</em>x<em class="arg">vertical</em></h4> 4812</div> 4813 4814<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> 4815 4816<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> 4817 4818<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> 4819 4820<div style="margin: auto;"> 4821 <h4><a name="resize" id="resize"></a>-resize <em class="arg">geometry</em></h4> 4822</div> 4823 4824<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> 4825 4826<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> 4827 4828<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> 4829 4830<div style="margin: auto;"> 4831 <h4><a name="respect-parentheses" id="respect-parentheses"></a>-respect-parentheses</h4> 4832</div> 4833 4834<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> 4835 4836<div style="margin: auto;"> 4837 <h4><a name="reverse" id="reverse"></a>-reverse</h4> 4838</div> 4839 4840<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> 4841 4842 4843<div style="margin: auto;"> 4844 <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> 4845</div> 4846 4847<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> 4848 4849<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> 4850 4851 4852<div style="margin: auto;"> 4853 <h4><a name="rotate" id="rotate"></a>-rotate <em class="arg">degrees</em>{<em class="arg"><</em>}{<em class="arg">></em>}</h4> 4854</div> 4855 4856<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> 4857 4858<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> 4859 4860<p>Empty triangles in the corners, left over from rotating the image, are 4861filled with the <kbd>background</kbd> color. </p> 4862 4863<p>See also the <a href="#distort">-distort</a> operator and specifically the 4864'<kbd>ScaleRotateTranslate</kbd>' distort method. </p> 4865 4866 4867<div style="margin: auto;"> 4868 <h4><a name="sample" id="sample"></a>-sample <em class="arg">geometry</em></h4> 4869</div> 4870 4871<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>scale image using pixel sampling.</td><td style='text-align:right;'></td></tr></table> 4872 4873<p><a href="#sample">-sample</a> ignores the current <a href="#resize">-resize</a> <a href="#filter">-filter</a> setting. The results are equivalent to using <a href="#resize">-resize</a> with a <a href="#filter">-filter</a> setting of <kbd>point</kbd>, though <a href="#sample">-sample</a> is a lot faster. </p> 4874 4875<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> 4876 4877 4878<div style="margin: auto;"> 4879 <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> 4880</div> 4881 4882<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> 4883 4884<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> 4885 4886<div style="margin: auto;"> 4887 <h4><a name="scale" id="scale"></a>-scale <em class="arg">geometry</em></h4> 4888</div> 4889 4890<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>scale the image.</td><td style='text-align:right;'></td></tr></table> 4891 4892<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="#scale">-scale</a> option uses a simpler, faster algorithm than <a href="#resize">-resize</a>, and it ignores the <a href="#filter">-filter</a> setting if one is present. Offsets, if present in the <em class="arg">geometry</em> string, are ignored, and the <a href="#gravity">-gravity</a> option has no effect.</p> 4893 4894<div style="margin: auto;"> 4895 <h4><a name="scene" id="scene"></a>-scene <em class="arg">value</em></h4> 4896</div> 4897 4898<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> 4899 4900<p>This option sets the scene number of an image or the first image in an image sequence.</p> 4901 4902<div style="margin: auto;"> 4903 <h4><a name="screen" id="screen"></a>-screen</h4> 4904</div> 4905 4906<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> 4907 4908<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> 4909 4910<div style="margin: auto;"> 4911 <h4><a name="seed" id="seed"></a>-seed</h4> 4912</div> 4913 4914<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> 4915 4916<div style="margin: auto;"> 4917 <h4><a name="segment" id="segment"></a>-segment <em class="arg">cluster-threshold</em>x<em class="arg">smoothing-threshold</em></h4> 4918</div> 4919 4920<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> 4921 4922<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> 4923 4924<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> 4925 4926<p>If the <a href="#verbose">-verbose</a> setting is defined, a detailed report 4927of the color clusters is returned.</p> 4928 4929 4930<div style="margin: auto;"> 4931 <h4><a name="selective-blur" id="selective-blur"></a>-selective-blur <em class="arg">geometry</em></h4> 4932</div> 4933 4934<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> 4935 4936<div style="margin: auto;"> 4937 <h4><a name="separate" id="separate"></a>-separate</h4> 4938</div> 4939 4940<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> 4941 4942<div style="margin: auto;"> 4943 <h4><a name="sepia-tone" id="sepia-tone"></a>-sepia-tone <em class="arg">threshold</em></h4> 4944</div> 4945 4946<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> 4947 4948<p>Specify <em class="arg">threshold</em> as the percent threshold of the intensity (0 - 99.9%).</p> 4949 4950<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> 4951 4952<div style="margin: auto;"> 4953 <h4><a name="set" id="set"></a>-set <em class="arg">attribute value</em></h4> 4954</div> 4955 4956<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>set an image attribute for all images in the current image sequence, after they have been created or read in. </td><td style='text-align:right;'></td></tr></table> 4957 4958<p>Attributes of interest include <a href="#comment">-comment</a>, <a href="#delay">-delay</a>, <a href="#dispose">-dispose</a>, and <a href="#page">-page</a>. For example:</p> 4959 4960<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'></span><span class="crtprompt"> $magick> </span><span class='crtin'>identify -format %c rose.png</span><span class='crtout'>Rose is a rose is a rose is a rose</span></p> 4961<p>The <a href="#repage">-repage</a> operator will also set the 4962'<kbd>page</kbd>' attribute of images already in memory, but allows you to 4963separately set the virtual canvas's size and offset components, and also allows 4964relative offset changes, and automatic canvas size re-calculating. The above 4965<a href="#set">-set</a> option is purely a direct, unmodified assignment of the 4966virtual canvas (page) meta-data. </p> 4967 4968<p>Set image options by prefixing the value with <kbd>option:</kbd>. Set attributes of the image registry by prefixing the value with <kbd>registry:</kbd>.</p> 4969 4970<div style="margin: auto;"> 4971 <h4><a name="shade" id="shade"></a>-shade <em class="arg">azimuth</em>x<em class="arg">elevation</em></h4> 4972</div> 4973 4974<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> 4975 4976<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> 4977 4978<div style="margin: auto;"> 4979 <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> 4980</div> 4981 4982<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> 4983 4984<div style="margin: auto;"> 4985 <h4><a name="shared-memory" 4986id="shared-memory"></a>-shared-memory</h4> 4987</div> 4988 4989<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> 4990 4991<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> 4992 4993<div style="margin: auto;"> 4994 <h4><a name="sharpen" id="sharpen"></a>-sharpen <em class="arg">radius</em>{x<em class="arg">sigma</em>}</h4> 4995</div> 4996 4997<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> 4998 4999<p>Use a Gaussian operator of the given radius and standard deviation (sigma).</p> 5000 5001<div style="margin: auto;"> 5002 <h4><a name="shave" id="shave"></a>-shave <em class="arg">geometry</em></h4> 5003</div> 5004 5005<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> 5006 5007<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> 5008 5009<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> 5010 5011<div style="margin: auto;"> 5012 <h4><a name="shear" id="shear"></a>-shear <em class="arg">Xdegrees</em>[x<em class="arg">Ydegrees</em>]</h4> 5013</div> 5014 5015<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> 5016 5017<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> 5018 5019<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> 5020 5021<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> 5022 5023<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> 5024 5025<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> 5026<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> 5027 5028<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert logo: -shear 20x60 logo-sheared.png</span></p> 5029<div style="margin: auto;"> 5030 <h4><a name="sigmoidal" id="sigmoidal-contrast"></a>-sigmoidal-contrast <em class="arg">contrast</em>x<em class="arg">mid-point</em></h4> 5031</div> 5032 5033<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> 5034 5035<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> 5036 5037<div style="margin: auto;"> 5038 <h4><a name="silent" id="silent"></a>-silent</h4> 5039</div> 5040 5041<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> 5042 5043<div style="margin: auto;"> 5044 <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> 5045</div> 5046 5047<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> 5048 5049<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> 5050 5051<p>For Photo CD images, choose from these sizes:</p> 5052 5053<pre class="text"> 5054 192x128 5055 384x256 5056 768x512 5057 1536x1024 5058 3072x2048 5059</pre> 5060 5061<div style="margin: auto;"> 5062 <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> 5063</div> 5064 5065<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> 5066 5067<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> 5068 5069<div style="margin: auto;"> 5070 <h4><a name="snaps" id="snaps"></a>-snaps <em class="arg">value</em></h4> 5071</div> 5072 5073<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> 5074 5075<p>Use this option to grab more than one image from the X server screen, to create an animation sequence.</p> 5076 5077<div style="margin: auto;"> 5078 <h4><a name="solarize" id="solarize"></a>-solarize <em class="arg">threshold</em></h4> 5079</div> 5080 5081<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> 5082 5083<p>Specify <em class="arg">factor</em> as the percent threshold of the intensity (0 - 99.9%).</p> 5084 5085<p>This option produces a <em class="arg">solarization</em> effect seen when exposing a photographic film to light during the development process.</p> 5086 5087<div style="margin: auto;"> 5088 <h4><a name="sparse-color" id="sparse-color"></a>-sparse-color <em 5089 class="arg">method</em> '<em class="arg">x</em>,<em class="arg">y</em> <em class="arg">color</em> ...'</h4> 5090</div> 5091 5092<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> 5093 5094 5095<table class="doc"> 5096 <tbody> 5097 <tr valign="top"> 5098 <th align="left" style="width: 8%">Method</th> 5099 <th align="left">Description</th> 5100 </tr> 5101 5102 <tr valign="top"> 5103 <td valign="top">voronoi</td> 5104 <td valign="top">Simply map each pixel to the to nearest color point 5105 given. The result are polygonal 'cells' of solid color. </td> 5106 </tr> 5107 5108 <tr valign="top"> 5109 <td valign="top">shepards</td> 5110 <td valign="top">Colors points basied on the ratio of inverse distance 5111 squared. Generating spots of color in a sea of the average of 5112 colors. </td> 5113 </tr> 5114 5115 <tr valign="top"> 5116 <td valign="top">barycentric</td> 5117 <td valign="top">three point triangle of color given 3 points. 5118 Giving only 2 points will form a linear gradient between those points. 5119 Gradient is however not restricted to just the triangle or line. </td> 5120 </tr> 5121 5122 <tr valign="top"> 5123 <td valign="top">bilinear</td> 5124 <td valign="top">Like barycentric but for 4 points. Less than 4 points 5125 fall back to barycentric. </td> 5126 </tr> 5127 5128 </tbody> 5129</table> 5130 5131<p>The points are placed according to the images location on the virtual 5132canvas (<a href="#page" >-page</a> or <a href="#repage" >-repage</a> 5133offset), and do not actually have to exist on the given image, but may be 5134some point beyond the edge of the image. All points are floating point values. 5135</p> 5136 5137<p>Only the color channels defined by the <a href="#channel" >-channel</a> are 5138modified, whcih means the matte/alpha transparency channel is not effected by 5139default. If enabled, the image also needs a the matte/alpha channel to be 5140enabled for this operator to effect an images transparency. This is typical 5141transparency handling for images. </p> 5142 5143<p>All the above methods when given a single point of color will replace all 5144the colors in the image with the color given, regardless of the point. This is 5145logical, and provides an alternative technique to recolor a image to some 5146default value. </p> 5147 5148 5149<div style="margin: auto;"> 5150 <h4><a name="splice" id="splice"></a>-splice <em class="arg">geometry</em></h4> 5151</div> 5152 5153<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> 5154 5155<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> 5156 5157<div style="margin: auto;"> 5158 <h4><a name="spread" id="spread"></a>-spread <em class="arg">amount</em></h4> 5159</div> 5160 5161<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> 5162 5163<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> 5164 5165<div style="margin: auto;"> 5166 <h4><a name="stegano" id="stegano"></a>-stegano <em class="arg">offset</em></h4> 5167</div> 5168 5169<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> 5170 5171<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> 5172 5173<div style="margin: auto;"> 5174 <h4><a name="stereo" id="stereo"></a>-stereo <em class="arg">+x</em>{<em class="arg">+y</em>}</h4> 5175</div> 5176 5177<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> 5178 5179<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> 5180 5181<div style="margin: auto;"> 5182 <h4><a name="storage-type" id="storage-type"></a>-storage-type <em class="arg">type</em></h4> 5183</div> 5184 5185<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> 5186 5187<pre class="text"> 5188 char store pixels as unsigned characters 5189 double store pixels as doubles 5190 float store pixels as floats 5191 integer store pixels as integers 5192 long store pixels as longs 5193 quantum store pixels in the native depth of your ImageMagick distribution 5194 short store pixels as unsigned shorts 5195</pre> 5196 5197<p>Float and double types are normalized from 0.0 to 1.0 otherwise the pixels 5198values range from 0 to the maximum value the storage type can support.</p> 5199 5200<div style="margin: auto;"> 5201 <h4><a name="stretch" id="stretch"></a>-stretch <em class="arg">fontStretch</em></h4> 5202</div> 5203 5204<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> 5205 5206<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> 5207 5208<pre class="text"> 5209 Any 5210 Condensed 5211 Expanded 5212 ExtraCondensed 5213 ExtraExpanded 5214 Normal 5215 SemiCondensed 5216 SemiExpanded 5217 UltraCondensed 5218 UltraExpanded 5219</pre> 5220 5221<p>To print a complete list of stretch types, use <a href="#list">-list stretch</a>.</p> 5222 5223<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> 5224 5225<div style="margin: auto;"> 5226 <h4><a name="strip" id="strip"></a>-strip</h4> 5227</div> 5228 5229<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> 5230 5231<div style="margin: auto;"> 5232 <h4><a name="stroke" id="stroke"></a>-stroke <em class="arg">color</em></h4> 5233</div> 5234 5235<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> 5236 5237<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 5238 5239<p>See <a href="#draw">-draw</a> for further details.</p> 5240 5241<div style="margin: auto;"> 5242 <h4><a name="strokewidth" id="strokewidth"></a>-strokewidth <em class="arg">value</em></h4> 5243</div> 5244 5245<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> 5246 5247<p>See <a href="#draw">-draw</a> for further details.</p> 5248 5249<div style="margin: auto;"> 5250 <h4><a name="style" id="style"></a>-style <em class="arg">fontStyle</em></h4> 5251</div> 5252 5253<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> 5254 5255<p>This setting suggests a font style that ImageMagick should try to apply to the currently selected font family. Select <em class="arg">fontStyle</em> from the following.</p> 5256 5257<pre class="text"> 5258 Any 5259 Italic 5260 Normal 5261 Oblique 5262</pre> 5263 5264<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> 5265 5266<div style="margin: auto;"> 5267 <h4><a name="swap" id="swap"></a>-swap <em class="arg">index,index</em></h4> 5268</div> 5269 5270<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> 5271 5272<p>For example, <a href="#swap">-swap 0,2</a> swaps the first and the third images in the current image sequence. Use <a href="#swap">+swap</a> to switch the last two images in the sequence.</p> 5273 5274<div style="margin: auto;"> 5275 <h4><a name="swirl" id="swirl"></a>-swirl <em class="arg">degrees</em></h4> 5276</div> 5277 5278<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> 5279 5280<p><em class="arg">Degrees</em> defines the tightness of the swirl.</p> 5281 5282<div style="margin: auto;"> 5283 <h4><a name="taint" id="taint"></a>-taint</h4> 5284</div> 5285 5286<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Mark the image as modified even if it isn't.</td><td style='text-align:right;'></td></tr></table> 5287 5288<div style="margin: auto;"> 5289 <h4><a name="text-font" id="text-font"></a>-text-font <em class="arg">name</em></h4> 5290</div> 5291 5292<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> 5293 5294<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> 5295 5296<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> 5297 5298<div style="margin: auto;"> 5299 <h4><a name="texture" id="texture"></a>-texture <em class="arg">filename</em></h4> 5300</div> 5301 5302<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> 5303 5304<div style="margin: auto;"> 5305 <h4><a name="threshold" id="threshold"></a>-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 5306</div> 5307 5308<!-- {<em class="arg">green,blue,opacity</em>} 5309<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> 5310--> 5311 5312<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> 5313 5314<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> 5315 5316<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. 5317</p> 5318 5319<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> 5320 5321<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert in.png -channel red -threshold 50% out.png</span></p> 5322<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> 5323 5324 5325<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> 5326<p>Note that the values of the transparency channel is treated as 'matte' 5327values (0 is opaque) and not as 'alpha' values (0 is transparent).</p> 5328 5329<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>. 5330</p> 5331 5332<div style="margin: auto;"> 5333 <h4><a name="thumbnail" id="thumbnail"></a>-thumbnail <em class="arg">geometry</em></h4> 5334</div> 5335 5336<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> 5337 5338<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> 5339 5340<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> 5341 5342<div style="margin: auto;"> 5343 <h4><a name="tile" id="tile"></a>-tile <em class="arg">filename</em></h4> 5344</div> 5345 5346<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> 5347 5348<div style="margin: auto;"> 5349 <h4>-tile <em class="arg">geometry</em></h4> 5350</div> 5351 5352<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> 5353 5354<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> 5355 5356<div style="margin: auto;"> 5357 <h4>-tile</h4> 5358</div> 5359 5360<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> 5361 5362<div style="margin: auto;"> 5363 <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> 5364</div> 5365 5366<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> 5367 5368<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> 5369 5370<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> 5371 5372<div style="margin: auto;"> 5373 <h4><a name="tint" id="tint"></a>-tint <em class="arg">value</em></h4> 5374</div> 5375 5376<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> 5377 5378<p>Tint the image with the fill color.</p> 5379 5380<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> 5381 5382<div style="margin: auto;"> 5383 <h4><a name="title" id="title"></a>-title <em class="arg">string</em></h4> 5384</div> 5385 5386<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> 5387 5388<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> 5389 5390<p>For example,</p> 5391 5392<p class="crtsnip"> 5393 -title "%m:%f %wx%h" 5394</p> 5395 5396<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> 5397 5398 5399<div style="margin: auto;"> 5400 <h4><a name="transform" id="transform"></a>-transform</h4> 5401</div> 5402 5403<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> 5404 5405<p>This option applies the transformation matrix from a previous <a href="#affine">-affine</a> option.</p> 5406 5407<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> 5408<div style="margin: auto;"> 5409 <h4><a name="transparent" id="transparent"></a>-transparent <em class="arg">color</em></h4> 5410</div> 5411 5412<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> 5413 5414<p>The <em class="arg">color</em> argument is defined using the format 5415described under the <a href="#fill">-fill</a> option. The <a href="#fuzz" 5416>-fuzz</a> setting can be used to match and replace colors similar to the one 5417given. </p> 5418 5419<p>The <a href="#opaque">-opaque</a> operator is exactly the same as <a 5420href="#transparent" >-transparent</a> but replaces the matching color same as 5421the current <a href="#fill">-fill</a> color setting. </p> 5422 5423<p>This does not define the 'transparency color' used for color-mapped image 5424formats, such as GIF. For that use <a href="#transparent-color" 5425>-transparent-color</a> </p> 5426 5427<p>Use <a href="#opaque">+opaque</a> to invert the pixels matched, that is 5428paint any pixel that does not match the target color, with the fill color.</p> 5429 5430 5431<div style="margin: auto;"> 5432 <h4><a name="transparent-color" id="transparent-color"></a>-transparent-color <em class="arg">color</em></h4> 5433</div> 5434 5435<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> 5436 5437<p>Sometimes this is used for saving to image formats such as 5438GIF and PNG8 which uses this color to represent boolean transparency. This 5439does not make a color transparent, it only defines what color the transparent 5440color is in the color palette of the saved image. Use <a 5441href="#transparent">-transparent</a> to make an opaque color transparent.</p> 5442 5443<p>This option allows you to have both an opaque visible color, as well as a 5444transparent color of the same color value without conflict. That is, you can 5445use the same color for both the transparent and opaque color areas within an 5446image. This, in turn, frees to you to select a transparent color that is 5447appropriate when an image is displayed by an application that does not handle a 5448transparent color index, while allowing ImageMagick to correctly handle images of this 5449type. </p> 5450 5451<p>The default transparent color is <kbd>#00000000</kbd>, which is fully transparent black.</p> 5452 5453<div style="margin: auto;"> 5454 <h4><a name="transpose" id="transpose"></a>-transpose</h4> 5455</div> 5456 5457<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> 5458 5459<p> This option mathematically transposes the pixel array. It is equivalent to the sequence <kbd>-flip -rotate 90</kbd>. 5460</p> 5461 5462<div style="margin: auto;"> 5463 <h4><a name="transverse" id="transverse"></a>-transverse</h4> 5464</div> 5465 5466<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> 5467 5468 5469<div style="margin: auto;"> 5470 <h4><a name="treedepth" id="treedepth"></a>-treedepth <em class="arg">value</em></h4> 5471</div> 5472 5473<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> 5474 5475<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> 5476 5477<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> 5478 5479<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> 5480 5481<div style="margin: auto;"> 5482 <h4><a name="trim" id="trim"></a>-trim</h4> 5483</div> 5484 5485<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> 5486 5487<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> 5488 5489<p>The page or virtual canvas information of the image is preserved allowing 5490you to extract the result of the <a href="#trim">-trim</a> operation from the 5491image. Use a <a href="#repage">+repage</a> to remove the virtual canvas page 5492information if it is unwanted.</p> 5493 5494<p>If the trimmed image 'disappears' an warning is produced, and a special 5495single pixel transparent 'missed' image is returned, in the same way as when a 5496<a href="#crop">-crop</a> operation 'misses' the image proper. </p> 5497 5498 5499<div style="margin: auto;"> 5500 <h4><a name="type" id="type"></a>-type <em class="arg">type</em></h4> 5501</div> 5502 5503<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> 5504 <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> 5505 5506<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> 5507 5508<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert bird.png -type TrueColor bird.jpg</span></p> 5509<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> 5510 5511<p>Use <a href="#type">-type optimize</a> to ensure the image is written in the smallest possible file size.</p> 5512 5513<div style="margin: auto;"> 5514 <h4><a name="undercolor" id="undercolor"></a>-undercolor <em class="arg">color</em></h4> 5515</div> 5516 5517<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> 5518 5519<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 5520 5521<p>See <a href="#draw">-draw</a> for further details.</p> 5522 5523 5524<div style="margin: auto;"> 5525 <h4><a name="update" id="update"></a>-update <em class="arg">seconds</em></h4> 5526</div> 5527 5528<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> 5529 5530<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> 5531 5532 5533<div style="margin: auto;"> 5534 <h4><a name="unique-colors" id="unique-colors"></a>-unique-colors</h4> 5535</div> 5536 5537<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> 5538 5539 5540<div style="margin: auto;"> 5541 <h4><a name="units" id="units"></a>-units <em class="arg">type</em></h4> 5542</div> 5543 5544<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> 5545 5546<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> 5547 5548 5549<div style="margin: auto;"> 5550 <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> 5551</div> 5552 5553<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> 5554 5555<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> 5556 5557<p>The parameters are:</p> 5558 5559<pre class="text"> 5560 radius: The radius of the Gaussian, in pixels, not counting the center 5561 pixel (default 0). 5562 sigma: The standard deviation of the Gaussian, in pixels (default 1.0). 5563 amount: The fraction of the difference between the original and the blur 5564 image that is added back into the original (default 1.0). 5565 threshold: The threshold, as a fraction of <em class="QR">QuantumRange</em>, needed to apply the 5566 difference amount (default 0.05). 5567</pre> 5568 5569 5570<div style="margin: auto;"> 5571 <h4><a name="verbose" id="verbose"></a>-verbose</h4> 5572</div> 5573 5574<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 preceds the <a href="#identify">-identify</a> option or <kbd>info:</kbd>.</td><td style='text-align:right;'></td></tr></table> 5575 5576 5577<div style="margin: auto;"> 5578 <h4><a name="version" id="version"></a>-version</h4> 5579</div> 5580 5581<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> 5582 5583 5584<div style="margin: auto;"> 5585 <h4><a name="view" id="view"></a>-view <em class="arg">string</em></h4> 5586</div> 5587 5588<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> 5589 5590 5591<div style="margin: auto;"> 5592 <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> 5593</div> 5594 5595<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> 5596 5597 5598<div style="margin: auto;"> 5599 <h4><a name="virtual-pixel" id="virtual-pixel"></a>-virtual-pixel <em class="arg">method</em></h4> 5600</div> 5601 5602<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> 5603 5604<p>This option defines what color source should be used if and when a color 5605lookup completely 'misses' the source image. The color(s) that appear to 5606surround the source image. Generally this color is derived from the source 5607image, but could also be set to a specify background color. </p> 5608 5609<p>Choose from these methods:</p> 5610 5611<pre class="text"> 5612 background: the area surrounding the image is the background color 5613 black: the area surrounding the image is black 5614 checker-tile: alternate squares with image and background color 5615 dither: non-random 32x32 dithered pattern 5616 edge: extend the edge pixel toward infinity 5617 gray: the area surrounding the image is gray 5618 horizontal-tile: horizontally tile the image, background color above/below 5619 horizontal-tile-edge: horizontally tile the image and replicate the side edge pixels 5620 mirror: mirror tile the image 5621 random: choose a random pixel from the image 5622 tile: tile the image (default) 5623 transparent: the area surrounding the image is transparent blackness 5624 vertical-tile: vertically tile the image, sides are background color 5625 vertical-tile-edge: vertically tile the image and replicate the side edge pixels 5626 white: the area surrounding the image is white 5627</pre> 5628 5629<p>The default value is "edge".</p> 5630 5631<p>This most important for distortion operators such as <a href="#distort" 5632>-distort</a>, <a href="#implode" >-implode</a>, and <a href="#fx" >-fx</a>. 5633However it also effects operations that may access pixels just outside the 5634image proper, such as <a href="#convolve">-convolve</a>, <a 5635href="#blur">-blur</a>, and <a href="#sharpen">-sharpen</a>. </p> 5636 5637<p>To print a complete list of virtual pixel types, use the <a href="#list">-list virtual-pixel</a> option.</p> 5638 5639 5640<div style="margin: auto;"> 5641 <h4><a name="visual" id="visual"></a>-visual <em class="arg">type</em></h4> 5642</div> 5643 5644<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> 5645 5646<p>Choose from these visual classes:</p> 5647 5648<pre class="text"> 5649 StaticGray 5650 GrayScale 5651 StaticColor 5652 PseudoColor 5653 TrueColor 5654 DirectColor 5655 default 5656 visual id 5657</pre> 5658 5659<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> 5660 5661 5662<div style="margin: auto;"> 5663 <h4><a name="watermark" id="watermark"></a>-watermark <em 5664 class="arg">brightness</em>x<em class="arg">saturation</em></h4> 5665</div> 5666 5667<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 5668saturation.</td><td style='text-align:right;'>[<a href="/www/composite.html">composite</a>]</td></tr></table> 5669 5670<p>Take a grayscale image (with alpha mask) and modify the destination image's 5671brightness according to watermark image's grayscale value and the <em 5672class="arg">brightness</em> percentage. The destinations color saturation 5673attribute is just direct modified by the <em class="arg">saturation</em> 5674percentage, which defaults to 100 percent (no color change). </p> 5675 5676 5677<div style="margin: auto;"> 5678 <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> 5679</div> 5680 5681<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> 5682 5683<p>Specify <em class="arg">amplitude</em> and <em class="arg">wavelength</em> of the wave.</p> 5684 5685<div style="margin: auto;"> 5686 <h4><a name="weight" id="weight"></a>-weight <em class="arg">fontWeight</em></h4> 5687</div> 5688 5689<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> 5690 5691<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> 5692 5693<table class="doc"> 5694 <col width="25%" /> 5695 <col width="75%" /> 5696 <thead> 5697 <tr> 5698 <th><em class="arg">fontWeight</em></th> 5699 <th>Description</th> 5700 </tr> 5701 </thead> 5702 <tbody> 5703 <tr><td>All </td> <td>No effect. </td></tr> 5704 <tr><td>Bold </td> <td>Same as <em class="arg">fontWeight</em> = 700.</td></tr> 5705 <tr><td>Bolder </td> <td>Add 100 to font weight if currently ≤ 800.</td></tr> 5706 <tr><td>Lighter </td> <td>Subtract 100 to font weight if currently ≤ 100.</td></tr> 5707 <tr><td>Normal </td> <td>Same as <em class="arg">fontWeight</em> = 400.</td></tr> 5708 </tbody> 5709 </table> 5710 5711<p>To print a complete list of weight types, use <a href="#list">-list weight</a>.</p> 5712 5713<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> 5714 5715<div style="margin: auto;"> 5716 <h4><a name="white-point" id="white-point"></a>-white-point <em class="arg">x,y</em></h4> 5717</div> 5718 5719<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> 5720 5721<div style="margin: auto;"> 5722 <h4><a name="white-threshold" id="white-threshold"></a>-white-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 5723</div> 5724 5725<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> 5726 5727<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. 5728</p> 5729 5730<div style="margin: auto;"> 5731 <h4><a name="window" id="window"></a>-window <em class="arg">id</em></h4> 5732</div> 5733 5734<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> 5735 5736<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> 5737 5738<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> 5739 5740<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> 5741 5742<div style="margin: auto;"> 5743 <h4><a name="window-group" id="window-group"></a>-window-group</h4> 5744</div> 5745 5746<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> 5747 5748<div style="margin: auto;"> 5749 <h4><a name="write" id="write"></a>-write <em class="arg">filename</em></h4> 5750</div> 5751 5752<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> 5753 <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> 5754 5755<p>Use <a href="#compress">-compress</a> to specify the type of image compression.</p> 5756 5757 5758</div> 5759 5760<div id="linkbar"> 5761 <!-- <span id="linkbar-west"> </span> --> 5762 <span id="linkbar-center"> 5763 <a href="http://www.imagemagick.org/discourse-server/">Discourse Server</a> • 5764 <a href="http://www.imagemagick.org/MagickStudio/scripts/MagickStudio.cgi">Studio</a> 5765 </span> 5766 <span id="linkbar-east"> </span> 5767 </div> 5768 <div class="footer"> 5769 <span id="footer-west">© 1999-2010 ImageMagick Studio LLC</span> 5770 <span id="footer-east"> <a href="http://www.imagemagick.org/script/contact.php">Contact the Wizards</a></span> 5771 </div> 5772 <div style="clear: both; margin: 0; width: 100%; "></div> 5773</body> 5774</html> 5775
