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href="/www/command-line-options.html#ordered-dither">‑ordered‑dither</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#orient">‑orient</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#page">‑page</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#paint">‑paint</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#path">‑path</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#pause_animate_">‑pause[animate]</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#pause_import_">‑pause[import]</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#pen">‑pen</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#ping">‑ping</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#pointsize">‑pointsize</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#polaroid">‑polaroid</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#posterize">‑posterize</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#precision">‑precision</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#preview">‑preview</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#print">‑print</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#process">‑process</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#profile">‑profile</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#quality">‑quality</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#quantize">‑quantize</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#quiet">‑quiet</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#radial-blur">‑radial‑blur</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#raise">‑raise</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#random-threshold">‑random‑threshold</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#red-primary">‑red‑primary</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#regard-warnings">‑regard‑warnings</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#region">‑region</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#remap">‑remap</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#remote">‑remote</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#render">‑render</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#repage">‑repage</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#resample">‑resample</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#resize">‑resize</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#respect-parentheses">‑respect‑parentheses</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#reverse">‑reverse</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#roll">‑roll</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#rotate">‑rotate</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#sample">‑sample</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#sampling-factor">‑sampling‑factor</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#scale">‑scale</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#scene">‑scene</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#screen">‑screen</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#seed">‑seed</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#segment">‑segment</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#selective-blur">‑selective‑blur</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#separate">‑separate</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#sepia-tone">‑sepia‑tone</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#set">‑set</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#shade">‑shade</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#shadow">‑shadow</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#shared-memory">‑shared‑memory</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#sharpen">‑sharpen</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#shave">‑shave</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#shear">‑shear</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#sigmoidal-contrast">‑sigmoidal‑contrast</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#silent">‑silent</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#size">‑size</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#sketch">‑sketch</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#snaps">‑snaps</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#solarize">‑solarize</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#sparse-color">‑sparse‑color</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#splice">‑splice</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#spread">‑spread</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#stegano">‑stegano</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#stereo">‑stereo</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#stretch">‑stretch</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#strip">‑strip</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#stroke">‑stroke</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#strokewidth">‑strokewidth</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#style">‑style</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#subimage-search">‑subimage‑search</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#swap">‑swap</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#swirl">‑swirl</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#synchronize">‑synchronize</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#taint">‑taint</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#text-font">‑text‑font</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#texture">‑texture</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#threshold">‑threshold</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#thumbnail">‑thumbnail</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#tile">‑tile</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#tile-offset">‑tile‑offset</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#tint">‑tint</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#title">‑title</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#transform">‑transform</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#transparent">‑transparent</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#transparent-color">‑transparent‑color</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#transpose">‑transpose</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#transverse">‑transverse</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#treedepth">‑treedepth</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#trim">‑trim</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#type">‑type</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#undercolor">‑undercolor</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#unique-colors">‑unique‑colors</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#units">‑units</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#unsharp">‑unsharp</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#update">‑update</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#verbose">‑verbose</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#version">‑version</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#view">‑view</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#vignette">‑vignette</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#virtual-pixel">‑virtual‑pixel</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#visual">‑visual</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#watermark">‑watermark</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#wave">‑wave</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#weight">‑weight</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#white-point">‑white‑point</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#white-threshold">‑white‑threshold</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#window">‑window</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#window-group">‑window‑group</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#write">‑write</a> ] </p> 179 180<p>Below is list of command-line options recognized by the ImageMagick <a 181href="/www/command-line-tools.html">command-line 182tools</a>. If you want a description of a particular option, click on the 183option name in the navigation bar above and you will go right to it. Unless 184otherwise noted, each option is recognized by the commands <a href="/www/convert.html">convert</a>, <a href="/www/mogrify.html">mogrify</a>.</p> 185 186<div style="margin: auto;"> 187 <h4><a name="adaptive-blur" id="adaptive-blur"></a>-adaptive-blur <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4> 188</div> 189 190<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Adaptively blur pixels, with decreasing effect near edges.</td><td style='text-align:right;'></td></tr></table> 191 "direction", 192<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> 193 194<div style="margin: auto;"> 195 <h4><a name="adaptive-resize" id="adaptive-resize"></a>-adaptive-resize <em class="arg">geometry</em></h4> 196</div> 197 198<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> 199 200<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> 201 202<div style="margin: auto;"> 203 <h4><a name="adaptive-sharpen" id="adaptive-sharpen"></a>-adaptive-sharpen <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4> 204</div> 205 206<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> 207 208<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> 209 210<div style="margin: auto;"> 211 <h4><a name="adjoin" id="adjoin"></a>-adjoin</h4> 212</div> 213 214<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> 215 216<p>This option is enabled by default. An attempt is made to save all 217images of an image sequence into the given output file. 218However, some formats, such as JPEG and PNG, do not support more than one 219image per file, and in that case ImageMagick is forced to write each image as a separate file. As 220such, if more than one image needs to be written, the filename given is 221modified by adding a <a href="#scene">-scene</a> number before the 222suffix, in order to make distinct names for each image. </p> 223 224<p>Use <a href="#adjoin">+adjoin</a> to force each image to be written 225to separate files, whether or not the file format allows multiple images 226per file (for example, GIF, MIFF, and TIFF). </p> 227 228<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> 229 230<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert logo: rose: -morph 15 my%02dmorph.jpg</span></p> 231<p>will create a sequence of 17 images named my00morph.jpg, my01morph.jpg, my02morph.jpg, ..., my16morph.jpg. 232</p> 233 234<p>In summary, ImageMagick tries to write all images to one file, but will use 235multiple files if either (1) the output image's file format does not allow multi-image files, 236(2) the <a href="#adjoin">+adjoin</a> option is given, or (3) a C-style integer format string is 237present in the output filename. </p> 238 239 240<div style="margin: auto;"> 241 <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/> 242 -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> 243</div> 244 245<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> 246 247<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> 248 249<p>The matrix entries are entered as comma-separated numeric values <i>with no spaces</i>. </p> 250 251<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> 252 253<div class="eqn"> 254<img alt="affine transformation" src="/images/affine.png"/> 255</div> 256 257<p> 258The 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> 259 260<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> 261 262<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> 263 264<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> 265 266<p class="crtsnip"> 267 -affine <em class="arg">s<sub>x</sub></em>,0,0,<em class="arg">s<sub>y</sub></em> 268</p> 269 270<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> 271 272<p class="crtsnip"> 273 -affine 1,0,0,1,<em class="arg">t<sub>x</sub></em>,<em class="arg">t<sub>y</sub></em> 274</p> 275 276<p>Rotate clockwise about the origin (the upper left-hand corner) by an angle <em>a</em> by letting 277<em>c</em> = cos(<em>a</em>), <em>s</em> = sin(<em>a</em>), and using the following.</p> 278 279<p class="crtsnip"> 280 -affine <em>c</em>,<em>s</em>,-<em>s</em>,<em>c</em> 281</p> 282 283<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> 284 285<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> 286 287<div style="margin: auto;"> 288 <h4><a name="alpha" id="alpha"></a>-alpha <em class="arg">type</em></h4> 289</div> 290 291<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> 292 293<p>Used to set a flag on an image indicating whether or not to use existing alpha 294channel 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> 295 296 297<table class="doc"> 298 <tbody> 299 <tr valign="top"> 300 <th align="left" style="width: 8%">type</th> 301 <th align="left">Description</th> 302 </tr> 303 304 <tr valign="top"> 305 <td valign="top"><kbd>Activate</kbd> or <kbd>On</kbd></td> 306 <td valign="top"> 307 Enable the image's transparency channel. Note normally <kbd>Set</kbd> 308 should be used instead of this, unless you specifically need to 309 preserve existing (but specifically turned <kbd>Off</kbd>) transparency 310 channel. </td></tr> 311 312 <tr valign="top"> 313 <td valign="top"><kbd>Deactivate</kbd> or <kbd>Off</kbd></td> 314 <td valign="top"> 315 Disables the image's transparency channel. Does not delete or change the 316 existing data, just turns off the use of that data.</td></tr> 317 318 <tr valign="top"> 319 <td valign="top"><kbd>Set</kbd></td> 320 <td valign="top"> 321 Activates the alpha/matte channel. If it was previously turned off 322 then it also resets the channel to opaque. If the image already had 323 the alpha channel turned on, it will have no effect.</td></tr> 324 325 <tr valign="top"> 326 <td valign="top"><kbd>Opaque</kbd></td> 327 <td valign="top"> 328 Enables the alpha/matte channel and forces it to be fully opaque. 329 </td></tr> 330 331 <tr valign="top"> 332 <td valign="top"><kbd>Transparent</kbd></td> 333 <td valign="top"> 334 Activates the alpha/matte channel and forces it to be fully 335 transparent. This effectively creates a fully transparent image the 336 same size as the original and with all its original RGB data still 337 intact, but fully transparent. </td></tr> 338 339 <tr valign="top"> 340 <td valign="top"><kbd>Extract</kbd></td> 341 <td valign="top"> 342 Copies the alpha channel values into all the color channels and turns 343 '<kbd>Off</kbd>' the the image's transparency, so as to generate 344 a gray-scale mask of the image's shape. The alpha channel data is left 345 intact just deactivated. This is the inverse of '<kbd>Copy</kbd>'. 346 </td></tr> 347 348 <tr valign="top"> 349 <td valign="top"><kbd>Copy</kbd></td> 350 <td valign="top"> 351 Turns '<kbd>On</kbd>' the alpha/matte channel, then copies the 352 gray-scale intensity of the image, into the alpha channel, converting 353 a gray-scale mask into a transparent shaped mask ready to be colored 354 appropriately. The color channels are not modified. </td></tr> 355 356 <tr valign="top"> 357 <td valign="top"><kbd>Shape</kbd></td> 358 <td valign="top"> 359 As per '<kbd>Copy</kbd>' but also colors the resulting shape mask with 360 the current background color. That is the RGB color channels is 361 replaced, with appropriate alpha shape. 362 </td></tr> 363 364 <tr valign="top"> 365 <td valign="top"><kbd>Background</kbd></td> 366 <td valign="top"> 367 Set any fully-transparent pixel to the background color, while leaving 368 it fully-transparent. This can make some image file formats, such as 369 PNG, smaller as the RGB values of transparent pixels are more uniform, 370 and thus can compress better. 371 </td></tr> 372 </tbody> 373</table> 374 375<p>Note that while the <a href="#matte" >+matte</a> operation is the same as 376"<kbd><a href="#alpha" >-alpha</a> Off</kbd>", the <a href="#matte" 377>-matte</a> operation is the same as "<kbd><a href="#alpha" >-alpha</a> 378Set</kbd>" and not "<kbd><a href="#alpha" >-alpha</a> On</kbd>". </p> 379 380 381<div style="margin: auto;"> 382 <h4><a name="annotate" id="annotate"></a> 383 -annotate <em class="arg">degrees</em> <em class="arg">text</em><br /> 384 -annotate <em class="arg">Xdegrees</em>x<em class="arg">Ydegrees</em> <em class="arg">text</em><br /> 385 -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> 386</div> 387 388<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> 389 390<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> 391 392 393<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> 394 395<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> 396 397<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> 398<div class="eqn"><img alt="annotate transformation" src="/images/annotate.png"/></div> 399 400<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> 401 402<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> 403 404<div style="margin: auto;"> 405 <h4><a name="antialias" id="antialias"></a>-antialias</h4> 406</div> 407 408<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 409drawing fonts and lines.</td><td style='text-align:right;'></td></tr></table> 410 411<p>By default, objects (e.g. text, lines, polygons, etc.) are antialiased when 412drawn. Use <a href="#antialias">+antialias</a> to disable the addition of 413antialiasing edge pixels. This will then reduce the number of colors added to 414an image to just the colors being directly drawn. That is, no mixed colors 415are added when drawing such objects. </p> 416 417<div style="margin: auto;"> 418 <h4><a name="append" id="append"></a>-append</h4> 419</div> 420 421<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> 422 423<p>This option creates a single longer image image, by joining all the current 424images in sequence top-to-bottom. Use <a href="#append">+append</a> to 425stack images left-to-right. </p> 426 427<p>If they are not of the same width, narrower images are padded with the 428current <a href="#background">-background</a> color setting, and their 429position relative to each other can be controlled by the current <a 430href="#gravity">-gravity</a> setting. </p> 431 432 433<div style="margin: auto;"> 434 <h4><a name="attenuate" id="attenuate"></a>-attenuate <em class="arg">value</em></h4> 435</div> 436 437<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> 438 439 440<div style="margin: auto;"> 441 <h4><a name="authenticate" id="authenticate"></a>-authenticate <em class="arg">password</em></h4> 442</div> 443 444<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> 445 446<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> 447 448<p>For a different encryption method, see <a href="#encipher">-encipher</a> and <a href="#decipher">-decipher</a>. </p> 449 450 451 452<div style="margin: auto;"> 453 <h4><a name="auto-gamma" id="auto-gamma"></a>-auto-gamma</h4> 454</div> 455 456<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> 457 458<p>This calculates the mean values of an image, then applies a calculated <a 459href="#gamma" >-gamma</a> adjustment so that is the mean color exists in the 460image it will get a have a value of 50%. </p> 461 462<p>This means that any solid 'gray' image becomes 50% gray. </p> 463 464<p>This works well for real-life images with little or no extreme dark and 465light areas, but tend to fail for images with large amounts of bright sky or 466dark shadows. It also does not work well for diagrams or cartoon like images. 467</p> 468 469<p>It uses the <a href="#channel" >-channel</a> setting, (including the 470'<CODE>sync</CODE>' flag for channel syncronization), to determine which color 471values is used and modified. As the default <a href="#channel" 472>-channel</a> setting is '<CODE>RGB,sync</CODE>', channels are modified 473together by the same gamma value, preserving colors. </p> 474 475 476 477<div style="margin: auto;"> 478 <h4><a name="auto-level" id="auto-level"></a>-auto-level</h4> 479</div> 480 481<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> 482 483<p>This is a 'perfect' image normalization operator. It finds the exact 484minimum and maximum color values in the image and then applies a <a 485href="#level" >-level</a> operator to stretch the values to the full range of 486values. </p> 487 488<p>The operator is not typically used for real-life images, image scans, or 489JPEG format images, as a single 'out-rider' pixel can set a bad min/max values 490for the <a href="#level" >-level</a> operation. On the other hand it is the 491right operator to use for color stretching gradient images being used to 492generate Color lookup tables, distortion maps, or other 'mathematically' 493defined images. </p> 494 495<p>The operator is very similar to the <a href="#normalize">-normalize</a>, <a 496href="#contrast-stretch" >-contrast-stretch</a>, and <a href="#linear-stretch" 497>-linear-stretch</a> operators, but without 'histogram binning' or 'clipping' 498problems that these operators may have. That is <a href="#auto-level" 499>-auto-level</a> is the perfect or ideal version these operators. </p> 500 501<p>It uses the <a href="#channel" >-channel</a> setting, (including the 502special '<CODE>sync</CODE>' flag for channel syncronization), to determine 503which color values are used and modified. As the default <a 504href="#channel" >+channel</a> setting is '<CODE>RGB,sync</CODE>', the 505'<CODE>sync</CODE>' ensures that the color channels will are modified 506together by the same gamma value, preserving colors, and ignoring 507transparency. </p> 508 509 510<div style="margin: auto;"> 511 <h4><a name="auto-orient" id="auto-orient"></a>-auto-orient</h4> 512</div> 513 514<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> 515 516<p>This operator reads and resets the EXIF image profile setting 'Orientation' 517and then performs the appropriate 90 degree rotation on the image to orient 518the image, for correct viewing. </p> 519 520<p>This EXIF profile setting is usually set using a gravity sensor in digital 521camara, however photos taken directly downward or upward may not have an 522appropriate value. Also images that have been orientation 'corrected' without 523reseting this setting, may be 'corrected' again resulting in a incorrect 524result. If the he EXIF profile was previously stripped, the <a 525href="#auto-orient" >-auto-orient</a> operator will do nothing. </p> 526 527 528<div style="margin: auto;"> 529 <h4><a name="average" id="average"></a>-average</h4> 530</div> 531 532<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> 533 534<p>An error results if the images are not identically sized.</p> 535 536 537<div style="margin: auto;"> 538 <h4><a name="backdrop" id="backdrop"></a>-backdrop</h4> 539</div> 540 541<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> 542 543<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> 544 545<div style="margin: auto;"> 546 <h4><a name="background" id="background"></a>-background <em class="arg">color</em></h4> 547</div> 548 549<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> 550 551<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> 552 553<div style="margin: auto;"> 554 <h4><a name="bench" id="bench"></a>-bench <em class="arg">iterations</em></h4> 555</div> 556 557<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> 558 559<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> 560 561<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> 562<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> 563 564<div style="margin: auto;"> 565 <h4><a name="bias" id="bias"></a>-bias <em class="arg">value</em>{<em class="arg">%</em>}</h4> 566</div> 567 568<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> 569 570<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> 571 572<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> 573 574<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 575negative results without clipping to the color value range 576(0..QuantumRange).</p> 577 578<p>See the discussion on HDRI implementations of ImageMagick on the page 579<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. 580</p> 581 582<div style="margin: auto;"> 583 <h4><a name="black-point-compensation" id="black-point-compensation"></a>-black-point-compensation</h4> 584</div> 585 586<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> 587 588<div style="margin: auto;"> 589 <h4><a name="black-threshold" id="black-threshold"></a>-black-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 590</div> 591 592<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> 593 594<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. 595</p> 596 597 598<div style="margin: auto;"> 599 <h4><a name="blend" id="blend"></a>-blend <em class="arg">geometry</em></h4> 600</div> 601 602<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>blend an image into another by the given absolute value or percent.</td><td style='text-align:right;'>[<a href="/www/composite.html">composite</a>]</td></tr></table> 603 604<p>Blend will average the images together ('plus') according to the 605percentages given and each pixels transparency. If only a single percentage 606value is given it sets the weight of the composite or 'source' image, while 607the background image is weighted by the exact opposite amount. That is a 608<kbd>-blend 30%</kbd> merges 30% of the 'source' image with 70% of the 609'destination' image. Thus it is equivalent to <kbd>-blend 30x70%</kbd>.</p> 610 611 612<div style="margin: auto;"> 613 <h4><a name="blue-primary" id="blue-primary"></a>-blue-primary <em class="arg">x</em>,<em class="arg">y</em></h4> 614</div> 615 616<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> 617 618<div style="margin: auto;"> 619 <h4><a name="blue-shift" id="blue-shift"></a>-blue-shift <em class="arg">factor</em></h4> 620</div> 621 622<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> 623 624<div style="margin: auto;"> 625 626<div style="margin: auto;"> 627 <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> 628</div> 629 630<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> 631 632<p>Convolve the image with a Gaussian or normal distribution using the given 633<em class="arg" >Sigma</em> value. The formula is:</p> 634 635<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="/images/gaussian-blur.png"/> 636</div> 637 638<p>The <em class="arg" >Sigma</em> value is the important argument, and 639determines the actual amount of bluring that will take place. </p> 640 641<p>The <em class="arg" >Radius</em> is only used to determine the size of the 642array which will hold the calculated gaussian distribution. It should be an 643integer. If not given, or set to zero, IM will calculate the largest possible 644radius that will provide meaningful results for the Gaussian distribution. 645</p> 646 647<p>The larger the <em class="arg" >Radius</em> the radius the slower the 648operation is. However too small a <em class="arg" >Radius</em>, and sever 649aliasing effects may result. As a guideline, <em class="arg" >Radius</em> 650should be at least twice the <em class="arg" >Sigma</em> value, though three 651times will produce a more accurite result. </p> 652 653<p>This option differs from <a href="#gaussian-blur">-gaussian-blur</a> simply 654by taking advantage of the separability properties of the distribution. Here 655we apply a single-dimensional Gaussian matrix in the horizontal direction, 656then repeat the process in the vertical direction.</p> 657 658<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 659pixels which are outside the image proper are blurred into the final result. 660</p> 661 662 663<div style="margin: auto;"> 664 <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> 665</div> 666 667<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> 668 669<p>Each pixel in the overlaid region is replaced with an Elliptical Weighted 670Average (EWA) of the source image, scaled according to the grayscale 671mapping. </p> 672 673<p>The ellipse is weighted with sigma set to the given <em class="arg" 674>Width</em> and <em class="arg" >Height</em>. The <em class="arg" >Height</em> 675defaults to the <em class="arg" >Width</em> for a normal circular Guassian 676weighting. The <em class="arg" >Angle</em> will rotate the ellipse from 677horizontal clock-wise. </p> 678 679<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 680pixels which are outside the image proper are blurred into the final result. 681</p> 682 683 684<div style="margin: auto;"> 685 <h4><a name="border" id="border"></a>-border <em class="arg">geometry</em></h4> 686</div> 687 688<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> 689 690<p>Set the width and height using the <em class="arg">size</em> portion of the 691<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 692ignored. </p> 693 694<p>Set the border color by preceding with the <a 695href="#bordercolor">-bordercolor</a> setting.</p> 696 697<p>The <a href="#border">-border</a> operation is affected by the current <a 698href="#compose">-compose</a> setting and assumes that this is using the default 699'<kbd>Over</kbd>' composition method. It generates a image of the appropriate 700size colors by the current <a href="#bordercolor">-bordercolor</a> before 701overlaying the original image in the center of this net image. This means that 702with the default compose method of '<kbd>Over</kbd>' any transparent parts may 703be replaced by the current <a href="#bordercolor">-bordercolor</a> setting.</p> 704<p>See also the <a href="#frame">-frame</a> option, which has more 705functionality.</p> 706 707<div style="margin: auto;"> 708 <h4><a name="bordercolor" id="bordercolor"></a>-bordercolor <em class="arg">color</em></h4> 709</div> 710 711<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> 712 713<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 714 715<p>The default border color is <kbd>#DFDFDF</kbd>, <span style="background-color: #dfdfdf;">this shade of gray</span>.</p> 716 717<div style="margin: auto;"> 718 <h4><a name="borderwidth" id="borderwidth"></a>-borderwidth <em class="arg">geometry</em> </h4> 719</div> 720 721<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> 722 723<div style="margin: auto;"> 724 <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> 725</div> 726 727<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> 728 729<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> 730 731<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> 732 733<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> 734 735<p>The slope varies from 0 at contrast=-100 to almost vertical at contrast=+100. For brightness=0 and contrast=-100, the result are totally midgray. For brightness=0 and contrast=+100, the result will approach but not quite reach a threshold at midgray; that is the linear transformation is a very steep vertical line at mid gray.</p> 736 737<p>Negative slopes, i.e. negating the image, are not possible with this function. All achievable slopes are zero or positive.</p> 738 739<p>The offset varies from -0.5 at brightness=-100 to 0 at brightness=0 to +0.5 at brightness=+100. Thus, when contrast=0 and brightness=100, the result is totally white. Similarly, when contrast=0 and brightness=-100, the result is totally black.</p> 740 741<p>As the range of values for the arguments are -100 to +100, adding the '%' symbol is no different than leaving it off.</p> 742 743<div style="margin: auto;"> 744 <h4><a name="cache" id="cache"></a>-cache <em class="arg">threshold</em></h4> 745</div> 746 747<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> 748 749<div style="margin: auto;"> 750 <h4><a name="caption" id="caption"></a>-caption <em class="arg">string</em></h4> 751</div> 752 753<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> 754 755<p>This option sets the caption meta-data of an image read in after this 756option has been given. To modify a caption of images already in memory use 757"<kbd><a href="#set">-set</a> caption</kbd>". </p> 758 759<p>The caption can contain special format characters listed in the <a 760href="/www/escape.html">Format and 761Print Image Properties</a>. These attributes are expanded when the caption 762is finally assigned to the individual images. </p> 763 764<p>If the first character of <em class="arg">string</em> is <em 765class="arg">@</em>, the image caption is read from a file titled by the 766remaining characters in the string. Comments read in from a file are literal; 767no embedded formatting characters are recognized.</p> 768 769<p>Caption meta-data ais not visible on the image itself. To do that use the 770<a href="#annotate">-annotate</a> or <a href="#draw">-draw</a> options 771instead.</p> 772 773<p>For example,</p> 774 775<p class="crtsnip"> 776 -caption "%m:%f %wx%h" bird.miff 777</p> 778 779<p>produces an image caption of <kbd>MIFF:bird.miff 512x480</kbd> (assuming 780that the image <kbd>bird.miff</kbd> has a width of 512 and a height of 781480.</p> 782 783 784<div style="margin: auto;"> 785 <h4><a name="cdl" id="cdl"></a>-cdl <em class="arg">filename</em></h4> 786</div> 787 788<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> 789 790<p>Here is an example color correction collection:</p> 791 792<pre class="text"> 793<?xml version="1.0" encoding="UTF-8"?> 794<ColorCorrectionCollection xmlns="urn:ASC:CDL:v1.2"> 795 <ColorCorrection id="cc06668"> 796 <SOPNode> 797 <Slope> 0.9 1.2 0.5 </Slope> 798 <Offset> 0.4 -0.5 0.6 </Offset> 799 <Power> 1.0 0.8 1.5 </Power> 800 </SOPNode> 801 <SATNode> 802 <Saturation> 0.85 </Saturation> 803 </SATNode> 804 </ColorCorrection> 805</ColorCorrectionCollection> 806</pre> 807 808<div style="margin: auto;"> 809 <h4><a name="channel" id="channel"></a>-channel <em class="arg">type</em></h4> 810</div> 811 812<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> 813 814<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> 815 816<p>The channels above can also be specified as a comma-separated list or can be 817abbreviated as a concatenation of the letters '<kbd>R</kbd>', '<kbd>G</kbd>', 818'<kbd>B</kbd>', '<kbd>A</kbd>', '<kbd>O</kbd>', '<kbd>C</kbd>', 819'<kbd>M</kbd>', '<kbd>Y</kbd>', '<kbd>K</kbd>'. 820 821For example, to only select the <kbd>Red</kbd> and <kbd>Blue</kbd> channels 822you can either use </p> 823<p class="crtsnip"> 824 -channel Red,Blue 825</p> 826<p>or you can use the short hand form</p> 827<p class="crtsnip"> 828 -channel RB 829</p> 830 831<p>All the channels that is present in an image can be specified using the 832special channel type <kbd>All</kbd>. Not all operators are 'channel capable', 833but generally any operators that are generally 'grey-scale' image operators, 834will understand this setting. See individual operator documentation. </p> 835 836<br> 837 838<p>On top of the normal channel selection a extra flag can be specified, 839'<kbd>Sync</kbd>'. This is turned on by default and if set means that 840operators that understand this flag should perform: cross-channel 841syncronization of the channels. If not specified, then most grey-scale 842operators will apply their image processing operations to each individual 843channel (as specified by the rest of the <a href="#channel">-channel</a> 844setting) completely independently from each other. </p> 845 846<p>For example for operators such as <a href="#auto-level">-auto-level</a> and 847<a href="#auto-gamma">-auto-gamma</a> the color channels are modified 848together in exactly the same way so that colors will remain in-sync. Without 849it being set, then each channel is modified separately and 850independently, which may produce color distortion. </p> 851 852<p>The <a href="#morphology">-morphology</a> '<kdb>Convolve</kdb>' method 853and the <a href="#compose">-compose</a> mathematical methods, also understands 854the '<kbd>Sync</kbd>' flag to modify the behaviour of pixel colors according 855to the alpha channel (if present). That is to say it will modify the image 856processing with the understanding that fully-transparent colors should not 857contribute to the final result. </p> 858 859Basically, by default, operators work with color channels in syncronous, and 860treats transparency as special, unless the <a href="#channel">-channel</a> 861setting is modified so as to remove the effect of the '<kbd>Sync</kbd>' flag. 862How each operator does this depends on that operators current implementation. 863Not all operators understands this flag at this time, but that is changing. 864</p> 865 866<p>To print a complete list of channel types, use <a href="#list">-list 867channel</a>.</p> 868 869<br> 870 871<p>By default, ImageMagick sets <a href="#channel">-channel</a> to the value 872'<kbd>RGBK,sync</kbd>', which specifies that operators act on all color 873channels except the transparency channel, and that all the color channels are 874to be modified in exactly the same way, with a understanding of transprancy 875(depending on the operation being applied). The 'plus' form <a 876href="#channel" >+channel</a> will reset the value back to this default. </p> 877 878<p>Options that are affected by the <a href="#channel" >-channel</a> setting 879include the following. 880 881<a href="#auto-gamma">-auto-gamma</a>, 882<a href="#auto-level">-auto-level</a>, 883<a href="#black-threshold">-black-threshold</a>, 884<a href="#blur">-blur</a>, 885<a href="#clamp">-clamp</a>, 886<a href="#clut">-clut</a>, 887<a href="#combine">-combine</a>, 888<a href="#composite">-composite</a> (Mathematical compose methods only), 889<a href="#convolve">-convolve</a>, 890<a href="#contrast-stretch">-contrast-stretch</a>, 891<a href="#evaluate">-evaluate</a>, 892<a href="#function">-function</a>, 893<a href="#fx">-fx</a>, 894<a href="#gaussian-blur">-gaussian-blur</a>, 895<a href="#hald-clut">-hald-clut</a>, 896<a href="#motion-blur">-motion-blur</a>, 897<a href="#morphology">-morphology</a>, 898<a href="#negate">-negate</a>, 899<a href="#normalize">-normalize</a>, 900<a href="#ordered-dither">-ordered-dither</a>, 901<a href="#radial-blur">-radial-blur</a>, 902<a href="#random-threshold">-random-threshold</a>, 903<a href="#separate">-separate</a>, 904<a href="#threshold">-threshold</a>, and 905<a href="#white-threshold">-white-threshold</a>. 906</p> 907 908<p>Warning, some operators behave differently when the <a href="#channel" 909>+channel</a> default setting is in effect, verses ANY user defined <a 910href="#channel" >-channel</a> setting (including the equivalent of the 911default). These operators have yet to be made to understand the newer 'Sync' 912flag. </p> 913 914<p>For example <a href="#threshold">-threshold</a> will by default gray-scale 915the image before thresholding, if no <a href="#channel" >-channel</a> setting 916has been defined. This is not 'Sync flag controlled, yet. </p> 917 918<p>Also some operators such as <a href="#blur">-blur</a>, <a 919href="#gaussian-blur">-gaussian-blur</a>, will modify their handling of the 920color channels if the '<kbd>alpha</kbd>' channel is also enabled by <a 921href="#channel" >-channel</a>. Generally this done to ensure that 922fully-transparent colors are treated as being fully-transparent, and thus any 923underlying 'hidden' color has no effect on the final results. Typically 924resulting in 'halo' effects. The newer <a href="#morphology">-morphology</a> 925convolution equivalents however does have a understanding of the 'Sync' flag 926and will thus handle transparency correctly by default. </p> 927 928<p>As a alpha channel is optional within images, some operators will read the 929color channels of an image as a greyscale alpha mask, when the image has no 930alpha channel present, and the <a href="#channel" >-channel</a> setting tells 931the operator to apply the operation using alpha channels. The <a 932href="#clut">-clut</a> operator is a good example of this. </p> 933 934 935<div style="margin: auto;"> 936 <h4><a name="clamp" id="clamp"></a>-clamp</h4> 937</div> 938 939<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> 940 941<div style="margin: auto;"> 942 <h4><a name="charcoal" id="charcoal"></a>-charcoal <em class="arg">factor</em></h4> 943</div> 944 945<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> 946 947<div style="margin: auto;"> 948 <h4><a name="chop" id="chop"></a>-chop <em class="arg">geometry</em></h4> 949</div> 950 951<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> 952 953<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> 954 955<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> 956 957<div style="margin: auto;"> 958 <h4><a name="clip" id="clip"></a>-clip</h4> 959</div> 960 961<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> 962 963<p>If a clipping path is present, it is applied to subsequent operations.</p> 964 965<p>For example, in the command</p> 966 967<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -clip -negate cockatoo.tif negated.tif</span></p> 968<p>only the pixels within the clipping path are negated.</p> 969 970<p>The <a href="#clip">-clip</a> feature requires the XML library. If the XML library is not present, the option is ignored.</p> 971 972<div style="margin: auto;"> 973 <h4><a name="clip-mask" id="clip-mask"></a>-clip-mask</h4> 974</div> 975 976<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> 977 978<div style="margin: auto;"> 979 <h4><a name="clip-path" id="clip-path"></a>-clip-path <em class="arg">id</em></h4> 980</div> 981 982<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> 983 984<div style="margin: auto;"> 985 <h4><a name="clone" id="clone"></a>-clone <em class="arg">index(s)</em></h4> 986</div> 987 988<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> 989 990<p>Specify the image by its index in the sequence. The first image is index 9910. Negative indexes are relative to the end of the sequence; for example, −1 992represents the last image of the sequence. Specify a range of images with a 993dash (e.g. 0−4). Separate multiple indexes with commas but no spaces (e.g. 0,2,5). Use <a 994href="#clone">+clone</a> make a copy of the last image in the image 995sequence.</p> 996 997<div style="margin: auto;"> 998 <h4><a name="clut" id="clut"></a>-clut</h4> 999</div> 1000 1001<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 1002corresponding channel in the second image as a <b>c</b>olor 1003<b>l</b>ook<b>u</b>p <b>t</b>able.</td><td style='text-align:right;'></td></tr></table> 1004 1005<p>The second (LUT) image is ordinarily a gradient image containing the 1006histogram mapping of how each channel should be modified. Typically it is a 1007either a single row or column image of replacement color values. If larger 1008than a single row or column, values are taken from a diagonal line from 1009top-left to bottom-right corners.</p> 1010 1011<p>The lookup is further controlled by the <a 1012href="#interpolate">-interpolate</a> setting, which is especially handy for an 1013LUT which is not the full length needed by the ImageMagick installed Quality 1014(Q) level. Good settings for this are the '<kbd>bilinear</kbd>' and 1015'<kbd>bicubic</kbd>' interpolation settings, which give smooth color 1016gradients, and the '<kbd>integer</kbd>' setting for a direct, unsmoothed 1017lookup of color values. </p> 1018 1019<p>This operator is especially suited to replacing a grayscale image with a 1020specific color gradient from the CLUT image. </p> 1021 1022<p>Only the channel values defined by the <a href="#channel">-channel</a> 1023setting will have their values replaced. In particular, since the default <a 1024href="#channel">-channel</a> setting is <kbd>RGB</kbd>, this means that 1025transparency (alpha/matte channel) is not affected, unless the <a 1026href="#channel">-channel</a> setting is modified. When the alpha channel is 1027set, it is treated by the <a href="#clut" >-clut</a> operator in the same way 1028as the other channels, implying that alpha/matte values are replaced using the 1029alpha/matte values of the original image. </p> 1030 1031<p>If either the image being modified, or the lookup image, contains no 1032transparency (i.e. <a href="#alpha" >-alpha</a> is turned 'off') but the <a 1033href="#channel">-channel</a> setting includes alpha replacement, then it is 1034assumed that image represents a gray-scale gradient which is used for the 1035replacement alpha values. That is you can use a gray-scale CLUT image to 1036adjust a existing images alpha channel, or you can color a gray-scale image 1037using colors form CLUT containing the desired colors, including transparency. 1038</p> 1039 1040<p>See also <a href="#hald-clut" >-hald-clut</a> which replaces colors according 1041the lookup of the full color RGB value from a 2D representation of a 3D color 1042cube. </p> 1043 1044 1045<div style="margin: auto;"> 1046 <h4><a name="coalesce" id="coalesce"></a>-coalesce</h4> 1047</div> 1048 1049<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> 1050 1051<p>Overlay each image in an image sequence according to its <a href="#dispose">-dispose</a> meta-data, to reproduce the look of an animation at each point in the animation sequence. All images should be the same size, and are assigned appropriate GIF disposal settings for the animation to continue working as expected as a GIF animation. Such frames are more easily viewed and processed than the highly optimized GIF overlay images. </p> 1052 1053<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> 1054 1055 1056<div style="margin: auto;"> 1057 <h4><a name="colorize" id="colorize"></a>-colorize <em class="arg">value</em></h4> 1058</div> 1059 1060<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> 1061 1062<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> 1063 1064<div style="margin: auto;"> 1065 <h4><a name="colormap" id="colormap"></a>-colormap <em class="arg">type</em></h4> 1066</div> 1067 1068<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> 1069 1070<p>The <em class="arg">type</em> can be <kbd>shared</kbd> or <kbd>private</kbd>.</p> 1071 1072<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> 1073 1074<div style="margin: auto;"> 1075 <h4><a name="colors" id="colors"></a>-colors <em class="arg">value</em></h4> 1076</div> 1077 1078<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> 1079 1080<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> 1081 1082<div style="margin: auto;"> 1083 <h4><a name="color-matrix" id="color-matrix"></a>-color-matrix <em class="arg">matrix</em></h4> 1084</div> 1085 1086<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>apply color correction to the image.</td><td style='text-align:right;'></td></tr></table> 1087 1088<p>This option permits saturation changes, hue rotation, luminance to alpha, and various other effects. Although variable-sized transformation matrices can be used, typically one uses a 5x5 matrix for an RGBA image and a 6x6 for CMYKA (or RGBA with offsets). The matrix is similar to those used by Adobe Flash except offsets are in column 6 rather than 5 (in support of CMYKA images) and offsets are normalized (divide Flash offset by 255).</p> 1089 1090<p>As an example, to add contrast to an image with offsets, try this command:</p> 1091 1092<pre class="text"> 1093convert kittens.jpg -color-matrix \ 1094 " 1.5 0.0 0.0 0.0, 0.0, -0.157 \ 1095 0.0 1.5 0.0 0.0, 0.0, -0.157 \ 1096 0.0 0.0 1.5 0.0, 0.0, -0.157 \ 1097 0.0 0.0 0.0 1.0, 0.0, 0.0 \ 1098 0.0 0.0 0.0 0.0, 1.0, 0.0 \ 1099 0.0 0.0 0.0 0.0, 0.0, 1.0" kittens.png 1100</pre> 1101<div style="margin: auto;"> 1102 <h4><a name="colorspace" id="colorspace"></a>-colorspace <em class="arg">value</em></h4> 1103</div> 1104 1105<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> 1106 1107<p>Choices are:</p> 1108 1109<pre class="text"> 1110 CMY 1111 CMYK 1112 Gray 1113 HSB 1114 HSL 1115 HWB 1116 Lab 1117 Log 1118 OHTA 1119 Rec601Luma 1120 Rec601YCbCr 1121 Rec709Luma 1122 Rec709YCbCr 1123 RGB 1124 sRGB 1125 Transparent 1126 XYZ 1127 YCbCr 1128 YCC 1129 YIQ 1130 YPbPr 1131 YUV 1132</pre> 1133 1134<p>To print a complete list of colorspaces, use <a href="#list">-list colorspace</a>.</p> 1135 1136<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> 1137 1138<table class="doc"> 1139 <caption>Conversion Of RGB To Other Color Spaces</caption> 1140 <tr><th align="left" valign="middle">CMY</th></tr> 1141 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>−R</td></tr> 1142 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>−G</td></tr> 1143 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>−B</td></tr> 1144 <tr><th align="left" valign="middle">CMYK — starts with CMY from above</th></tr> 1145 <tr><td align="left" valign="middle">K=min(C,Y,M)</td></tr> 1146 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>*(C−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 1147 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>*(M−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 1148 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>*(Y−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 1149 1150 <tr><th align="left" valign="middle">Gray</th></tr> 1151 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr> 1152 1153 <tr><th align="left" valign="middle">HSB — Hue, Saturation, Brightness; like a cone peak downward</th></tr> 1154 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr> 1155 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr> 1156 <tr><td align="left" valign="middle">B=distance along axis from bottom upward; B=max(R,G,B); <em>intensity-like</em></td></tr> 1157 1158 <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> 1159 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr> 1160 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr> 1161 <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> 1162 1163 <tr><th align="left" valign="middle">HWB — Hue, Whiteness, Blackness</th></tr> 1164 <tr><td align="left" valign="middle">Hue (complicated equation)</td></tr> 1165 <tr><td align="left" valign="middle">Whiteness (complicated equation)</td></tr> 1166 <tr><td align="left" valign="middle">Blackness (complicated equation)</td></tr> 1167 1168 <tr><th align="left" valign="middle">LAB</th></tr> 1169 <tr><td align="left" valign="middle">L (complicated equation relating X,Y,Z)</td></tr> 1170 <tr><td align="left" valign="middle">A (complicated equation relating X,Y,Z)</td></tr> 1171 <tr><td align="left" valign="middle">B (complicated equation relating X,Y,Z)</td></tr> 1172 1173 <tr><th align="left" valign="middle">LOG</th></tr> 1174 <tr><td align="left" valign="middle">I1 (complicated equation involving logarithm of R)</td></tr> 1175 <tr><td align="left" valign="middle">I2 (complicated equation involving logarithm of G)</td></tr> 1176 <tr><td align="left" valign="middle">I3 (complicated equation involving logarithm of B)</td></tr> 1177 1178 <tr><th align="left" valign="middle">OHTA — approximates principal components transformation</th></tr> 1179 <tr><td align="left" valign="middle">I1=0.33333*R+0.33334*G+0.33333*B; <em>intensity-like</em></td></tr> 1180 <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> 1181 <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> 1182 1183 <tr><th align="left" valign="middle">Rec601Luma</th></tr> 1184 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr> 1185 1186 <tr><th align="left" valign="middle">Rec601YCbCr</th></tr> 1187 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1188 <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> 1189 <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> 1190 1191 <tr><th align="left" valign="middle">Rec709Luma</th></tr> 1192 <tr><td align="left" valign="middle">Gray=0.21260*R+0.71520*G+0.07220*B</td></tr> 1193 1194 <tr><th align="left" valign="middle">Rec709YCbCr</th></tr> 1195 <tr><td align="left" valign="middle">Y=0.212600*R+0.715200*G+0.072200*B; <em>intensity-like</em></td></tr> 1196 <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> 1197 <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> 1198 1199 <tr><th align="left" valign="middle">sRGB</th></tr> 1200 <tr><td align="left" valign="middle">if Rs ≤ .03928 then Rs=R/12.92 else Rs=((R+.055)/1.055)^2.4</td></tr> 1201 <tr><td align="left" valign="middle">if Gs ≤ .03928 then Gs=B/12.92 else Gs=((G+.055)/1.055)^2.4</td></tr> 1202 <tr><td align="left" valign="middle">if Bs ≤ .03928 then Bs=B/12.92 else Bs=((B+.055)/1.055)^2.4</td></tr> 1203 1204 <tr><th align="left" valign="middle">XYZ</th></tr> 1205 <tr><td align="left" valign="middle">X=0.4124240*R+0.3575790*G+0.1804640*B</td></tr> 1206 <tr><td align="left" valign="middle">Y=0.2126560*R+0.7151580*G+0.0721856*B</td></tr> 1207 <tr><td align="left" valign="middle">Z=0.0193324*R+0.1191930*G+0.9504440*B</td></tr> 1208 1209 <tr><th align="left" valign="middle">YCC</th></tr> 1210 <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> 1211 <tr><td align="left" valign="middle">C1=(−0.29900*R−0.58700*G+0.88600*B) (with complicated scaling)</td></tr> 1212 <tr><td align="left" valign="middle">C2=(0.70100*R−0.58700*G−0.11400*B) (with complicated scaling)</td></tr> 1213 1214 <tr><th align="left" valign="middle">YCbCr</th></tr> 1215 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1216 <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> 1217 <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> 1218 1219 <tr><th align="left" valign="middle">YIQ</th></tr> 1220 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr> 1221 <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> 1222 <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> 1223 1224 <tr><th align="left" valign="middle">YPbPr</th></tr> 1225 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1226 <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> 1227 <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> 1228 1229 <tr><th align="left" valign="middle">YUV</th></tr> 1230 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr> 1231 <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> 1232 <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> 1233</table> 1234 1235<div style="margin: auto;"> 1236 <h4><a name="combine" id="combine"></a>-combine</h4> 1237</div> 1238 1239<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> 1240 1241<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> 1242 1243<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. 1244</p> 1245 1246<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert original.png -channel RGB -separate sepimage.png</span><span class='crtout'></span><span class="crtprompt"> $magick> </span><span class='crtin'>convert sepimage-0.png sepimage-1.png sepimage-2.png -channel RGB \ <br/> -combine imagecopy.png</span></p> 1247<div style="margin: auto;"> 1248 <h4><a name="comment" id="comment"></a>-comment <em class="arg">string</em></h4> 1249</div> 1250 1251<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> 1252 1253<p>This option sets the comment meta-data of an image read in after this 1254option has been given. To modify a comment of images already in memory use 1255"<kbd><a href="#set">-set</a> comment</kbd>". </p> 1256 1257<p>The comment can contain special format characters listed in the <a 1258href="/www/escape.html">Format and 1259Print Image Properties</a>. These attributes are expanded when the comment 1260is finally assigned to the individual images. </p> 1261 1262<p>If the first character of <em class="arg">string</em> is <em 1263class="arg">@</em>, the image comment is read from a file titled by the 1264remaining characters in the string. Comments read in from a file are literal; 1265no embedded formatting characters are recognized.</p> 1266 1267<p>Comment meta-data are not visible on the image itself. To do that use the 1268<a href="#annotate">-annotate</a> or <a href="#draw">-draw</a> options 1269instead.</p> 1270 1271<p>For example,</p> 1272 1273<p class="crtsnip"> 1274 -comment "%m:%f %wx%h" bird.miff 1275</p> 1276 1277<p>produces an image comment of <kbd>MIFF:bird.miff 512x480</kbd> (assuming 1278that the image <kbd>bird.miff</kbd> has a width of 512 and a height of 1279480.</p> 1280 1281<div style="margin: auto;"> 1282 <h4><a name="compose" id="compose"></a>-compose <em class="arg">operator</em></h4> 1283</div> 1284 1285<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> 1286 1287<p>See <a href="/www/compose.html">Alpha Compositing</a> for 1288a detailed discussion of alpha compositing.</p> 1289 1290<p>This setting effects image processing operators that merge two (or more) 1291images together in some way. This includes the operators, 1292<a href="#composite">-composite</a>, 1293<a href="#layers">-layers</a> composite, 1294<a href="#flatten">-flatten</a>, 1295<a href="#mosaic">-mosaic</a>, 1296<a href="#layers">-layers</a> merge, 1297<a href="#border">-border</a>, 1298<a href="#frame">-frame</a>, 1299and <a href="#extent">-extent</a>. </p> 1300 1301<p>It is also one of the primary options for the "<kbd>composite</kbd>" 1302command. </p> 1303 1304 1305<div style="margin: auto;"> 1306 <h4><a name="composite" id="composite"></a>-composite</h4> 1307</div> 1308 1309<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Perform alpha composition on two images and an optional mask</td><td style='text-align:right;'></td></tr></table> 1310 1311<p>Take the first image 'destination' and overlay the second 'source' image 1312according to the current <a href="#compose">-compose</a> setting. The location 1313of the 'source' or 'overlay' image is controlled according to <a 1314href="#geometry" >-geometry</a>, and <a href="#geometry" >-geometry</a> 1315settings. </p> 1316 1317<p>If a third image is given this is treated as a gray-scale 'mask' image 1318relative to the first 'destination' image. This mask will limit what parts of 1319the destination can be modified by the image composition. However for the 1320'<kbd>displace</kbd>' compose method, the mask is used to provide a separate 1321Y-displacement image instead. </p> 1322 1323<p>If a <a href="#compose">-compose</a> method requires extra numerical 1324arguments or flags these can be provided by setting the <a 1325href="#set">-set</a> '<kbd class="arg">option:compose:args</kbd>' 1326appropriately for the compose method. </p> 1327 1328<p>Some <a href="#compose">-compose</a> methods can modify the 'destination' 1329image outside the overlay area. You can disable this by setting the special <a 1330href="#set">-set</a> '<kbd class="arg">option:compose:outside-overlay</kbd>' 1331to '<kbd>false</kbd>'. </p> 1332 1333 1334<div style="margin: auto;"> 1335 <h4><a name="compress" id="compress"></a>-compress <em class="arg">type</em></h4> 1336</div> 1337 1338<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> 1339 1340<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> 1341 1342<p>To print a complete list of compression types, use <a href="#list">-list compress</a>.</p> 1343 1344<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> 1345 1346<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> 1347 1348<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> 1349 1350<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> 1351 1352<div style="margin: auto;"> 1353 <h4><a name="contrast" id="contrast"></a>-contrast</h4> 1354</div> 1355 1356<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> 1357 1358<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> 1359 1360<p>For a more pronounced effect you can repeat the option:</p> 1361 1362<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -contrast -contrast rose_c2.png</span></p> 1363<div style="margin: auto;"> 1364 <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> 1365</div> 1366 1367<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> 1368 1369<p>While performing the stretch, black-out at most <em 1370class="arg" >black-point</em> pixels and white-out at most <em 1371class="arg" >white-point</em> pixels. Or, if percent is used, black-out at most 1372<em class="arg" >black-point %</em> pixels and white-out at most <em 1373class="arg" >white-point %</em> pixels.</p> 1374 1375<p>Prior to ImageMagick 6.4.7-0, <a href="#contrast-stretch" 1376>-contrast-stretch</a> will black-out at most <em class="arg" 1377>black-point</em> pixels and white-out at most <em class="arg" >total pixels 1378minus white-point</em> pixels. Or, if percent is used, black-out at most <em 1379class="arg">black-point %</em> pixels and white-out at most <em class="arg" 1380>100% minus white-point %</em> pixels.</p> 1381 1382<p>Note that <kbd>-contrast-stretch 0</kbd> will modify the image such that 1383the image's min and max values are stretched to 0 and <em class="QR" 1384>QuantumRange</em>, respectively, without any loss of data due to burn-out or 1385clipping at either end. This is not the same as <a href="#normalize" 1386>-normalize</a>, which is equivalent to <kbd>-contrast-stretch 0.15x0.05%</kbd> (or 1387prior to ImageMagick 6.4.7-0, <kbd>-contrast-stretch 2%x99%</kbd>).</p> 1388 1389<p>Internally operator works by creating a histogram bin, and then uses that 1390bin to modify the image. As such some colors may be merged together when they 1391originally fell into the same 'bin'. </p> 1392 1393<p>All the channels are normalized in concert by the came amount so as to 1394preserve color integrity, when the default <a href="#channel" >+channel</a> 1395setting is in use. Specifying any other <a href="#channel" >-channel</a> 1396setting will normalize the RGB channels independently.</p> 1397 1398<p>See also <a href="#auto-level" >-auto-level</a> for a 'perfect' 1399normalization of mathematical images. </p> 1400 1401<p>This operator is under review for re-development. </p> 1402 1403 1404<div style="margin: auto;"> 1405 <h4><a name="convolve" id="convolve"></a>-convolve <em class="arg">kernel</em></h4> 1406</div> 1407 1408<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> 1409 1410<p>The <em class="arg">kernel</em> is a matrix specified as 1411a comma-separated list of integers (with no spaces), ordered left-to right, 1412starting with the top row. Presently, only odd-dimensioned kernels are 1413supported, and therefore the number of entries in the specified <em 1414class="arg">kernel</em> must be 3<sup>2</sup>=9, 5<sup>2</sup>=25, 14157<sup>2</sup>=49, etc. </p> 1416 1417<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 1418positive and negative results are relative to a user-specified bias value. 1419This is important for non-HDRI compilations of ImageMagick when dealing with 1420convolutions that contain negative as well as positive values. This is 1421especially the case with convolutions involving high pass filters or edge 1422detection. Without an output bias, the negative values is clipped at zero. 1423</p> 1424 1425<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 1426negative results without clipping to the color value range (0..QuantumRange). 1427See the discussion on HDRI implementations of ImageMagick on the page <a 1428href="/www/high-dynamic-range.html">High 1429Dynamic-Range Images</a>. For more about HDRI go the ImageMagick <a 1430href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this 1431<a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a> 1432entry. </p> 1433 1434 1435<div style="margin: auto;"> 1436 <h4><a name="crop" id="crop"></a>-crop <em class="arg">geometry</em></h4> 1437</div> 1438 1439<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> 1440 1441<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> 1442 1443<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> 1444 1445<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> 1446 1447<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> 1448 1449<p>By adding a exclamation character flag to the geometry argument, the 1450cropped images virtual canvas page size and offset is set as if the 1451geometry argument was a viewport or window. This means the canvas page size 1452is set to exactly the same size you specified, the image offset set 1453relative top left corner of the region cropped. </p> 1454 1455<p>If the cropped image 'missed' the actual image on its virtual canvas, a 1456special single pixel transparent 'missed' image is returned, and a 'crop 1457missed' warning given. </p> 1458 1459<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> 1460 1461<div style="margin: auto;"> 1462 <h4><a name="cycle" id="cycle"></a>-cycle <em class="arg">amount</em></h4> 1463</div> 1464 1465<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> 1466 1467<p><em class="arg">Amount</em> defines the number of positions each 1468colormap entry is shifted.</p> 1469 1470 1471<div style="margin: auto;"> 1472 <h4><a name="debug" id="debug"></a>-debug <em class="arg">events</em></h4> 1473</div> 1474 1475<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> 1476 1477<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> 1478 1479 1480<p>For example, to log cache and blob events, use.</p> 1481 1482<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -debug "Cache,Blob" rose: rose.png</span></p> 1483<p>The <kbd>User</kbd> domain is normally empty, but developers can log user events in their private copy of ImageMagick.</p> 1484 1485<p>To print the complete list of debug methods, use <a href="#list">-list debug</a>.</p> 1486 1487<p>Use the <a href="#log">-log</a> option to specify the format for debugging output.</p> 1488 1489<p>Use <a href="#debug">+debug</a> to turn off all logging.</p> 1490 1491<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> 1492 1493 1494<div style="margin: auto;"> 1495 <h4><a name="decipher" id="decipher"></a>-decipher <em class="arg">filename</em></h4> 1496</div> 1497 1498<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> 1499 1500<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p> 1501 1502<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p> 1503 1504 1505<div style="margin: auto;"> 1506 <h4><a name="deconstruct" id="deconstruct"></a>-deconstruct</h4> 1507</div> 1508 1509<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> 1510 1511<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> 1512 1513<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> 1514 1515<p>This option is actually equivalent to the <a href="#layers">-layers</a> method '<kbd>compare-any</kbd>'. </p> 1516 1517 1518<div style="margin: auto;"> 1519 <h4><a name="define" id="define"></a>-define <em class="arg">key</em>{<em class="arg">=value</em>}<em class="arg">...</em></h4> 1520</div> 1521 1522<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>add specific global settings generally used to control 1523coders and image processing operations.</td><td style='text-align:right;'></td></tr></table> 1524 1525<p>This option creates one or more definitions for coders and decoders to use 1526while reading and writing image data. Definitions are generally used to 1527control image file format coder modules, and image processing operations, 1528beyond what is provided by normal means. Defined settings are listed in <a 1529href="#verbose" >-verbose</a> information ("<kbd>info:</kbd>" output format) 1530as "Artifacts". </p> 1531 1532<p>If <em class="arg">value</em> is missing for a definition, an empty-valued 1533definition of a flag is created with that name. This used to control on/off 1534options. Use <a href="#define">+define key</a> to remove definitions 1535previously created. Use <a href="#define">+define "*"</a> to remove all 1536existing definitions.</p> 1537 1538<p>The same 'artifact' settings can also be defined using the <a 1539href="#set" >-set "option:<em class="arg">key</em>" "<em class="arg" 1540>value</em>"</a> option, which also allows the use of <a href="/www/escape.html" >Format and Print Image 1541Properties</a> in the defined value. </p> 1542 1543<p>Such settings are global in scope, and effect all images and operations. </p> 1544 1545<p>The following definitions are just some of the artifacts that are 1546available:</p> 1547 1548<ul> 1549 1550<dt>dcm:display-range=reset</dt> 1551<dd>Set the display range to the minimum and maximum pixel values for the 1552 DCM image format.</dd><br /> 1553 1554<dt>dot:layout-engine=<em class="arg">value</em></dt> 1555<dd>Set the specify the layout engine for the DOT image format (e.g. 1556 <kbd>neato</kbd>).</dd><br /> 1557 1558<dt>jpeg:extent=<em class="arg">value</em></dt> 1559<dd>Restrict the maximum JPEG file size, for example <kbd>-define 1560 jpeg:extent=400kb</kbd>.</dd><br /> 1561 1562<dt>jpeg:size=<em class="arg">geometry</em></dt> 1563<dd>Set the size hint of a JPEG image, for example, -define jpeg:size=128x128. 1564 It is most useful for increasing performance and reducing the memory 1565 requirements when reducing the size of a large JPEG image.</dd><br /> 1566 1567<dt>jp2:rate=<em class="arg">value</em></dt> 1568<dd>Specify the compression factor to use while writing JPEG-2000 files. The 1569 compression factor is the reciprocal of the compression ratio. The valid 1570 range is 0.0 to 1.0, with 1.0 indicating lossless compression. If defined, 1571 this value overrides the -quality setting. A quality setting of 75 1572 results in a rate value of 0.06641.</dd><br /> 1573 1574<dt>mng:need-cacheoff</dt> 1575 <dd>turn playback caching off for streaming MNG.</dd><br /> 1576 1577<dt>png:bit-depth=<em class="arg">value</em></dt> 1578<dt>png:color-type=<em class="arg">value</em></dt> 1579<dd>desired bit-depth and color-type for PNG output. You can force the PNG 1580 encoder to use a different bit-depth and color-type than it would have 1581 normally selected, but only if this does not cause any loss of image 1582 quality. Any attempt to reduce image quality is treated as an error and no 1583 PNG file is written. E.g., if you have a 1-bit black-and-white image, you 1584 can use these "defines" to cause it to be written as an 8-bit grayscale, 1585 indexed, or even a 64-bit RGBA. But if you have a 16-million color image, 1586 you cannot force it to be written as a grayscale or indexed PNG. If you 1587 wish to do this, you must use the appropriate <a href="#depth">-depth</a>, 1588 <a href="#colors">-colors</a>, or <a href="#type">-type</a> directives to 1589 reduce the image quality prior to using the PNG encoder. Note that in 1590 indexed PNG files, "bit-depth" refers to the number of bits per index, 1591 which can range from 1 to 8. In such files, the color samples always have 1592 8-bit depth.</dd><br /> 1593 1594<dt>ps:imagemask</dt> 1595<dd>If the ps:imagemask flag is defined, the PS3 and EPS3 coders will create 1596 Postscript files that render bilevel images with the Postscript imagemask 1597 operator instead of the image operator.</dd><br /> 1598 1599<dt>quantum:format=<em class="arg">type</em></dt> 1600<dd>Set the type to <kbd>floating-point</kbd> to specify a floating-point 1601 format for raw files (e.g. GRAY:) or for MIFF and TIFF images in HDRI mode 1602 to preserve negative values. If <a href="#depth">-depth</a> 16 is 1603 included, the result is a single precision floating point format. 1604 If <a href="#depth">-depth</a> 32 is included, the result is 1605 double precision floating point format.</dd> 1606 1607</ul> 1608 1609<p>For example, to create a postscript file that will render only the black 1610pixels of a bilevel image, use:</p> 1611 1612<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert bilevel.tif -define ps:imagemask eps3:stencil.ps</span></p> 1613<p>Set attributes of the image registry by prefixing the value with 1614<kbd>registry:</kbd>. For example, to set a temporary path to put work files, 1615use:</p> 1616 1617<p class="crtsnip"> 1618-define registry:temporary-path=/data/tmp 1619</p> 1620 1621 1622 1623<div style="margin: auto;"> 1624 <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> 1625</div> 1626 1627<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> 1628 1629<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> 1630 1631<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> 1632 1633 1634<div style="margin: auto;"> 1635 <h4><a name="delete" id="delete"></a>-delete <em class="arg">index</em></h4> 1636</div> 1637 1638<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> 1639 1640<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> 1641 1642 1643<div style="margin: auto;"> 1644 <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> 1645</div> 1646 1647<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> 1648 1649<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> 1650 1651<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> 1652 1653<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> 1654 1655<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> 1656 1657<div style="margin: auto;"> 1658 <h4><a name="depth" id="depth"></a>-depth <em class="arg">value</em></h4> 1659</div> 1660 1661<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> 1662 1663<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> 1664 1665<div style="margin: auto;"> 1666 <h4><a name="descend" id="descend"></a>-descend</h4> 1667</div> 1668 1669<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> 1670 1671<div style="margin: auto;"> 1672 <h4><a name="deskew" id="deskew"></a>-deskew <em class="arg">threshold</em></h4> 1673</div> 1674 1675<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> 1676 1677<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> 1678 1679<div style="margin: auto;"> 1680 <h4><a name="despeckle" id="despeckle"></a>-despeckle</h4> 1681</div> 1682 1683<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> 1684 1685<div style="margin: auto;"> 1686 <h4><a name="direction" id="direction"></a>-direction <em class="arg">type</em></h4> 1687</div> 1688 1689<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>render text right-to-left or left-to-right.</td><td style='text-align:right;'></td></tr></table> 1690 1691<div style="margin: auto;"> 1692 <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> 1693</div> 1694 1695<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> 1696 1697<p>With this option, the 'overlay' image, and optionally the 'mask' image, 1698is used as a displacement map, which is used to displace the lookup of 1699what part of the 'background' image is seen at each point of the overlaid 1700area. Much like the displacement map is a 'lens' that redirects light shining 1701through it so as to present a distorted view the original 'background' image 1702behind it. </p> 1703 1704<p>Any perfect grey areas of the displacement map produce a zero 1705displacement of the image. Black areas produce the given maximum negative 1706displacement of the lookup point, while white produce a maximum positive 1707displacement of the lookup. </p> 1708 1709<p>Note that it is the lookup of the 'background' that is displaced, not a 1710displacement of the image itself. As such an area of the displacement map 1711containing 'white' will have the lookup point 'shifted' by a positive amount, 1712and thus generating a copy of the destination image to the right/downward from 1713the correct position. That is the image will look like it may have been 1714'shifted' in a negative left/upward direction. Understanding this is a very 1715important in understanding how displacement maps work. </p> 1716 1717<p>The given arguments define the maximum amount of displacement in pixels 1718that a particular map can produce. If the displacement scale is large enough 1719it is also possible to lookup parts of the 'background' image that lie well 1720outside the bounds of the displacement map itself. That is you could very 1721easily copy a section of the original image from outside the overlay area 1722into the overlay area. </p> 1723 1724<p>The '%' flag makes the displacement scale relative to the size of the 1725overlay image (100% = half width/height of image). Using '!' switches 1726percentage arguments to refer to the destination image size instead. 1727these flags were added as of IM v6.5.3-5.</p> 1728 1729<p>Normally a single grayscale displacement map is provided, which with the 1730given scaling values will determine a single direction (vector) in which 1731displacements can occur (positively or negatively). However, if you also 1732specify a third image which is normally used as a <em class="arg">mask</em>, 1733the <em class="arg">composite image</em> is used for horizontal X 1734displacement, while the <em class="arg">mask image</em> is used for vertical Y 1735displacement. This allows you to define completely different displacement 1736values for the X and Y directions, and allowing you to lookup any point within 1737the <em class="arg">scale</em> bounds. In other words each pixel can lookup 1738any other nearby pixel, producing complex 2 dimensional displacements, rather 1739than a simple 1 dimensional vector displacements. </p> 1740 1741<p>Alteratively rather than suppling two separate images, as of IM v6.4.4-0, 1742you can use the 'red' channel of the overlay image to specify the horizontal 1743or X displacement, and the 'green' channel for the vertical or Y displacement. 1744</p> 1745 1746<p>As of IM v6.5.3-5 any alpha channel in the overlay image is used as a 1747mask the transparency of the destination image. However areas outside the 1748overlaid areas will not be effected. </p> 1749 1750 1751<div style="margin: auto;"> 1752 <h4><a name="display" id="display"></a>-display <em class="arg">host:display[.screen]</em></h4> 1753</div> 1754 1755<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> 1756 1757<p>This option is used with convert for obtaining image or font from this X server. See <em class="arg">X(1)</em>.</p> 1758 1759<div style="margin: auto;"> 1760 <h4><a name="dispose" id="dispose"></a>-dispose <em class="arg">method</em></h4> 1761</div> 1762 1763<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> 1764 1765<p>The layer disposal method defines the way each the displayed image is to be 1766modified after the current 'frame' of an animation has finished being 1767displayed (after its 'delay' period), but before the next frame on an 1768animation is to be overlaid onto the display. </p> 1769 1770<p>Here are the valid methods:</p> 1771 1772<pre class="text"> 1773Undefined 0 No disposal specified (equivalent to '<kbd>none</kbd>'). 1774None 1 Do not dispose, just overlay next frame image. 1775Background 2 Clear the frame area with the background color. 1776Previous 3 Clear to the image prior to this frames overlay. 1777</pre> 1778 1779<p>You can also use the numbers given above, which is what the GIF format 1780uses internally to represent the above settings. </p> 1781 1782<p>To print a complete list of dispose methods, use <a href="#list">-list dispose</a>.</p> 1783 1784<p>Use <a href="#dispose" >+dispose</a>, turn off the setting and prevent 1785resetting the layer disposal methods of images being read in. </p> 1786 1787<p>Use <a href="#set">-set</a> '<kbd>dispose</kbd>' method to set the image 1788disposal method for images already in memory.</p> 1789 1790<div style="margin: auto;"> 1791 <h4><a name="dissimilarity-threshold" id="dissimilarity-threshold"></a>-dissimilarity-threshold <em class="arg">value</em></h4> 1792</div> 1793 1794<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> 1795 1796 1797<div style="margin: auto;"> 1798 <h4><a name="dissolve" id="dissolve"></a>-dissolve <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]</h4> 1799</div> 1800 1801<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> 1802 1803<p>The opacity of the composite image is multiplied by the given percent, then 1804it is composited 'over' the main image. If <em class="arg">src_percent</em> 1805is greater than 100, start dissolving the main image so it becomes 1806transparent at a value of '<kbd class="arg">200</kbd>'. If both percentages 1807are given, each image are dissolved to the percentages given. </p> 1808 1809<p>Note that dissolve percentages do not add, two opaque images dissolved 1810'50,50', produce a 75% transparency. For a 50% + 50% blending of the two 1811images, you would need to use dissolve values of '50,100'. </p> 1812 1813<div style="margin: auto;"> 1814 <h4><a name="distort" id="distort"></a>-distort <em class="arg">method arguments</em></h4> 1815</div> 1816 1817<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> 1818 1819<p>The <em class="arg">arguments</em> is a single string containing a list 1820of floating point numbers separated by commas or spaces. The number of 1821and meaning of the floating point values depends on the distortion <em 1822class="arg">method</em> being used. </p> 1823 1824<p>Choose from these distortion types:</p> 1825 1826<table class="doc"> 1827 <tr valign="top"> 1828 <th align="left" style="width: 8%">Method</th> 1829 <th align="left">Description</th> 1830 </tr> 1831 1832 <tr valign="top"> 1833 <td valign="top"><kbd>ScaleRotateTranslate</kbd> 1834 <br/>or <kbd>SRT</kbd></td> 1835 <td valign="top"> 1836 Distort image by first scaling and rotating about a given 'center', 1837 before translating that 'center' to the new location, in that order. It 1838 is an alternative method of specifying a '<kbd>Affine</kbd>' type of 1839 distortion, but without shearing effects. It also provides a good way 1840 of rotating and displacing a smaller image for tiling onto a larger 1841 background (IE 2-dimensional animations). <br/> 1842 1843 The number of arguments determine the specific meaning of each 1844 argument for the scales, rotation, and translation operations. <br/> 1845 1846 <table style="margin-left:auto; margin-right:auto;"> 1847 <tr><td># </td><td>arguments meaning</td></tr> 1848 <tr><td>1:</td><td><em>Angle_of_Rotation</em></td></tr> 1849 <tr><td>2:</td><td><em>Scale Angle</em></td></tr> 1850 <tr><td>3:</td><td><em>ScaleX,ScaleY Angle</em></td></tr> 1851 <tr><td>4:</td><td><em>X,Y Scale Angle</em></td></tr> 1852 <tr><td>5:</td> 1853 <td><em>X,Y ScaleX,ScaleY Angle</em></td></tr> 1854 <tr><td>6:</td> 1855 <td><em>X,Y Scale Angle NewX,NewY</em></td></tr> 1856 <tr><td>7:</td> 1857 <td><em>X,Y ScaleX,ScaleY Angle 1858 NewX,NewY</em></td></tr> 1859 </table> 1860 1861 This is actually an alternative way of specifying a 2 dimensional linear 1862 '<kbd>Affine</kbd>' or '<kbd>AffineProjection</kbd>' distortion. </td> </tr> 1863 1864 <tr valign="top"> 1865 <td valign="top"><kbd>Affine</kbd></td> 1866 <td valign="top"> 1867 Distort the image linearly by moving a list of at least 3 or more sets 1868 of control points (as defined below). Ideally 3 sets or 12 floating 1869 point values are given allowing the image to be linearly scaled, 1870 rotated, sheared, and translated, according to those three points. See 1871 also the related '<kbd>AffineProjection</kbd>' and '<kbd>SRT</kbd>' 1872 distortions. <br/> 1873 1874 More than 3 sets given control point pairs (12 numbers) is least 1875 squares fitted to best match a lineary affine distortion. If only 2 1876 control point pairs (8 numbers) are given a two point image translation 1877 rotation and scaling is performed, without any possible shearing, 1878 flipping or changes in aspect ratio to the resulting image. If only one 1879 control point pair is provides the image is only translated, (which may 1880 be a floating point non-integer translation). <br/> 1881 1882 This distortion does not include any form of perspective distortion. 1883 </td> 1884 1885 </tr> 1886 1887 <tr valign="top"> 1888 <td valign="top"><kbd>AffineProjection</kbd></td> 1889 <td valign="top"> 1890 Linearly distort an image using the given Affine Matrix of 6 1891 pre-calculated coefficients forming a set of Affine Equations to map 1892 the source image to the destination image. 1893 1894 <div style="text-align: center"><em> 1895 s<sub>x</sub>, r<sub>x</sub>, 1896 r<sub>y</sub>, s<sub>y</sub>, 1897 t<sub>x</sub>, t<sub>y</sub> 1898 </em></div> 1899 1900 See <a href="#affine" >-affine</a> setting for more detail, and 1901 meanings of these coefficients. <br/> 1902 1903 The distortions '<kbd>Affine</kbd>' and '<kbd>SRT</kbd>' provide 1904 alternative methods of defining this distortion, with ImageMagick doing 1905 the calculations needed to generate the required coefficients. You can 1906 see the internally generated coefficients, by using a <a 1907 href="#verbose" >-verbose</a> setting with those other varients. </td> 1908 1909 </tr> 1910 1911 <tr valign="top"> 1912 <td valign="top"><kbd>BilinearForward</kbd><br/> 1913 <kbd>BilinearReverse</kbd></td> 1914 <td valign="top"> 1915 Bilinear Distortion, given a minimum of 4 sets of coordinate pairs, or 1916 16 values (see below). Not that lines may not appear straight after 1917 distortion, though the distance between coordinates will remain 1918 consistent. <br/> 1919 1920 The '<kbd>BilinearForward</kbd>' is used to map rectangles to any 1921 quadrilateral, while the '<kbd>BilinearReverse</kbd>' form maps any 1922 quadrilateral to a rectangle, while preserving the straigth line edges 1923 in each case. <br/> 1924 1925 Note that '<kbd>BilinearForward</kbd>' can generate invalid pixels 1926 which will be colored using the <a href="#mattecolor" >-mattecolor</a> 1927 color setting. Also if the quadraterial becomes 'flipped' the image 1928 may dissappear. <br/> 1929 1930 There are future plans to produce a true Bilinear distortion that will 1931 attempt to map any quadrilateral to any other quadrilateral, while 1932 preserving edges (and edge distance ratios). 1933 1934 </td> 1935 </tr> 1936 1937 <tr valign="top"> 1938 <td valign="top"><kbd>Perspective</kbd></td> 1939 <td valign="top"> 1940 Perspective distort the images, using a list of 4 or more sets of 1941 control points (as defined below). More that 4 sets (16 numbers) of 1942 control points provide least squares fitting for more accurate 1943 distortions (for the purposes of image registration and panarama 1944 effects). Less than 4 sets will fall back to a '<kbd>Affine</kbd>' 1945 linear distortion. <br/> 1946 1947 Perspective Distorted images ensures that straight lines remain 1948 straight, but the scale of the distorted image will vary. The horizon 1949 is anti-aliased, and the 'sky' color may be set using the 1950 <a href="#mattecolor" >-mattecolor</a> setting. </td> 1951 </tr> 1952 1953 <tr valign="top"> 1954 <td valign="top"><kbd>PerspectiveProjection</kbd> </td> 1955 <td valign="top"> 1956 Do a '<kbd>Perspective</kbd>' distortion biased on a set of 8 1957 pre-calculated coefficients. You can get these coefficients by looking 1958 at the <a href="#verbose" >-verbose</a> output of a 1959 '<kbd>Prespective</kbd>' distortion, or by calculating them yourself. 1960 If the last two perspective scaling coefficients are zero, the 1961 remaining 6 represents a transposed 'Affine Matrix'. </td> 1962 1963 </tr> 1964 1965 <tr valign="top"> 1966 <td valign="top"><kbd>Arc</kbd></td> 1967 <td valign="top"> 1968 Arc the image (variation of polar mapping) over the angle given around 1969 a circle. <br/> 1970 <table width="90%" style = "margin-left: auto; margin-right: auto;"> 1971 <tr valign="top"><td>Argument</td> 1972 <td>Meaning</td></tr> 1973 <tr valign="top"><td><em>arc_angle</em></td> 1974 <td>The angle over which to arc the image side-to-side</td></tr> 1975 <tr valign="top"><td><em>rotate_angle</em></td> 1976 <td>Angle to rotate resulting image from vertical center</td></tr> 1977 <tr valign="top"><td><em>top_radius</em></td> 1978 <td>Set top edge of source image at this radius</td></tr> 1979 <tr valign="top"><td><em>bottom_radius</em> </td> 1980 <td>Set bottom edge to this radius (radial scaling)</td></tr> 1981 </table> 1982 1983 The resulting image is always resized to best fit the resulting image, 1984 (as if using <a href="#distort" >+distort</a>) while attempting to 1985 preserve scale and aspect ratio of the original image as much as 1986 possible with the arguments given by the user. All four arguments will 1987 be needed to change the overall aspect ratio of an 'Arc'ed image. <br/> 1988 1989 This a variation of a polar distortion designed to try to preserve the 1990 aspect ratio of the image rather than direct Cartesian to Polar 1991 conversion. </td> 1992 </tr> 1993 1994 <tr valign="top"> 1995 <td valign="top"><kbd>Polar</kbd></td> 1996 <td valign="top"> 1997 Like '<kbd>Arc</kbd>' but do a complete Cartesian to Polar mapping of 1998 the image. that is the height of the input image is mapped to the 1999 radius limits, while the width is wrapped around between the 2000 angle limits. <br/> 2001 2002 Arguments: <em>Rmax,Rmin CenterX,CenterY, start,end_angle</em> <br/> 2003 2004 All arguments are optional. With <em>Rmin</em> defaulting to zero, the 2005 center to the center of the image, and the angles going from -180 (top) 2006 to +180 (top). If <em>Rmax</em> is given the special value of 2007 '<code>0</code>', the the distance from the center to the nearest edge 2008 is used for the radius of the output image, which will ensure the whole 2009 image is visible (though scaled smaller). However a special value of 2010 '<code>-1</code>' will use the distance from the center to the furthest 2011 corner, This may 'clip' the corners from the input rectangular image, 2012 but will generate the exact reverse of a '<kbd>DePolar</kbd>' with 2013 the same arguments. <br/> 2014 2015 If the plus form of distort (<a href="#distort" >+distort</a>) is used 2016 output image center will default to <code>0,0</code> of the virtual 2017 canvas, and the image size adjusted to ensure the whole input image is 2018 made visible in the output image on the virtual canvas. </td> 2019 2020 </tr> 2021 2022 <tr valign="top"> 2023 <td valign="top"><kbd>DePolar</kbd></td> 2024 <td valign="top"> 2025 Uses the same arguments and meanings as a '<kbd>Polar</kbd>' distortion 2026 but generates the reverse Polar to Cartesian distortion. <br/> 2027 2028 The special <em>Rmax</em> setting of '<code>0</code>' may however clip 2029 the corners of the input image. However using the special 2030 <em>Rmax</em> setting of '<code>-1</code>' (maximum center to corner 2031 distance) will ensure the whole distorted image is preserved in the 2032 generated result, so that the same argument to '<kbd>Polar</kbd>' will 2033 reverse the distortion re-producing the original. 2034 2035 Note that as this distortion requires the area resampling of a circular 2036 arc, which can not be handled by the builtin EWA resampling function. 2037 As such the normal EWA filters are turned off. It is recommended some 2038 form of 'super-sampling' image processing technique be used to produce 2039 a high quality result. </td> 2040 2041 </tr> 2042 2043 <tr valign="top"> 2044 <td valign="top"><kbd>Barrel</kbd></td> 2045 <td valign="top"> 2046 Given the four coefficients (A,B,C,D) as defined by <a 2047 href="http://www.all-in-one.ee/~dersch/barrel/barrel.html" >Helmut 2048 Dersch</a>, perform a barrell or pin-cushion distortion appropriate to 2049 correct radial lens distortions. That is in photographs, make straight 2050 lines straight again. <br/> 2051 2052 Arguments: <em>A B C</em> [ <em>D</em> [ 2053 <em>X</em> , <em>Y</em> ] ] <br/> 2054 or <em>A<sub>x</sub> B<sub>x</sub> C<sub>x</sub> D<sub>x</sub> 2055 A<sub>y</sub> B<sub>y</sub> C<sub>y</sub> D<sub>y</sub></em> 2056 [ <em>X</em> , <em>Y</em> ] <br/> 2057 So that it forms the function <br/> 2058 Rsrc = r * ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> + 2059 <em>C</em>*r + <em>D</em> )<br/> 2060 2061 Where <em>X</em>,<em>Y</em> is the optional center of the distortion 2062 (defaulting to the center of the image). <br/> 2063 The second form is typically used to distort images, rather than 2064 correct lens distortions. <br/> 2065 </td> 2066 2067 </tr> 2068 2069 <tr valign="top"> 2070 <td valign="top"><kbd>BarrelInverse</kbd></td> 2071 <td valign="top"> 2072 This is very simular to '<kbd>Barrel</kbd>' with the same set of 2073 arguments, and argument handling. However it uses the inverse 2074 of the radial polynomial, 2075 so that it forms the function <br/> 2076 Rsrc = r / ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> + 2077 <em>C</em>*r + <em>D</em> )<br/> 2078 Note that this is not the reverse of the '<kbd>Barrel</kbd>' 2079 distortion, just a different barrel-like radial distortion method. 2080 2081 </td> 2082 </tr> 2083 2084 <tr valign="top"> 2085 <td valign="top"><kbd>Shepards</kbd></td> 2086 <td valign="top"> 2087 Distort the given list control points (any number) using an Inverse 2088 Squared Distance Interpolation Method (<a 2089 href="http://en.wikipedia.org/wiki/Shepard%27s_method" >Shepards 2090 Method</a>). The control points in effect do 'localized' displacement 2091 of the image around the given control point (preserving the look and 2092 the rotation of the area near the control points. For best results 2093 extra control points should be added to 'lock' the positions of the 2094 corners, edges and other unchanging parts of the image, to prevent 2095 their movement. <br/> 2096 2097 The distortion has been likened to 'taffy pulling' using nails, or 2098 pins' stuck in a block of 'jelly' which is then moved to the new 2099 position, distorting te surface of the jelly. <br/> 2100 2101 Internally it is equivelent to generating a displacement map (see <a 2102 href="#displace" >-displace</a>) for source image color look-up using 2103 the <a href="#sparse-color" >-sparse-color</a> method of the same name. 2104 2105 </td> 2106 </tr> 2107 2108</table> 2109 2110<p>To print a complete list of distortion methods, use <a href="#list">-list 2111distort</a>.</p> 2112 2113<p>Many of the above distortion methods such as '<kbd>Affine</kbd>', 2114'<kbd>Perspective</kbd>', and '<kbd>Shepards</kbd>' use a list control points 2115defining how these points in the given image should be distorted in the 2116destination image. Each set of four floating point values represent a source 2117image coordinate, followed immediately by the destination image coordinate. 2118This produces a list of values such as...</p> 2119<div style="text-align: center"><em> 2120 U<sub>1</sub>,V<sub>1</sub> X<sub>1</sub>,Y<sub>1</sub> 2121 U<sub>2</sub>,V<sub>2</sub> X<sub>2</sub>,Y<sub>2</sub> 2122 U<sub>3</sub>,V<sub>3</sub> X<sub>3</sub>,Y<sub>3</sub> 2123 ... 2124 U<sub>n</sub>,V<sub>n</sub> X<sub>n</sub>,Y<sub>n</sub> 2125</em></div> 2126<p>where <em>U,V</em> on the source image is mapped to <em>X,Y</em> on the 2127destination image. </p> 2128 2129<p>For example, to warp an image using '<kbd>perspective</kbd>' distortion, 2130needs a list of at least 4 sets of coordinates, or 16 numbers. Here is the 2131perspective distortion of the built-in "rose:" image. Note how spaces were 2132used to group the 4 sets of coordinate pairs, to make it easier to read and 2133understand.</p> 2134 2135<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'> 2136convert rose: -virtual-pixel black \<br/> 2137 -distort Perspective '0,0,0,0 0,45,0,45 69,0,60,10 69,45,60,35' \<br/> 2138 rose_3d_rotated.gif</span></p> 2139<p>If more that the required number of coordinate pairs are given for 2140a distortion, the distortion method is 'least squares' fitted to produce the 2141best result for all the coordinate pairs given. If less than the ideal number 2142of points are given, the distort will generally fall back to a simpler form of 2143distortion that can handles the smaller number of coordinates (usally a linear 2144'<kbd>Affine</kbd>' distortion). </p> 2145 2146<p>By using more coordinates you can make use of image registration tool to 2147find matching coordinate pairs in overlapping images, so as to improve the 2148'fit' of the distortion. Of course a bad coordinate pair can also make the 2149'fit' worse. Caution is always advised. </p> 2150 2151<p>Colors are acquired from the source image according to the <a 2152href="#interpolate" >-interpolate</a> color lookup setting, when the image is 2153magnified. However if the viewed image is minified (image becomes smaller), 2154a special area resampling function (added ImageMagick v6.3.5-9), is used to 2155produce a higher quality image. For example you can use 2156a '<kbd>perspective</kbd>' distortion to view a infinitely tiled 'plane' all 2157the way to the horizon. </p> 2158 2159<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'> 2160convert -size 90x90 pattern:checkerboard -normalize -virtual-pixel tile \<br/> 2161 -distort perspective '0,0,5,45 89,0,45,46 0,89,0,89 89,89,89,89' \<br/> 2162 checks_tiled.jpg</span></p> 2163<p>Note that a infinitely tiled perspective images involving the horizon can 2164be very slow to generate due to the use of the high quality 'area resampling' 2165function (added ImageMagick v6.3.5-9). You can turn off 'area resampling' 2166using a <a href="#filter" >-filter</a> setting of '<kbd>point</kbd>' 2167(recommended if you plan to use super-sampling instead). </p> 2168 2169<p>If an image generates <i>invalid pixels</i>, such as the 'sky' in the last 2170'<kbd>perspective</kbd>' distortion example, <a href="#distort" >-distort</a> 2171will use the current <a href="#mattecolor" >-mattecolor</a> setting for these 2172pixels. If you do not what these pixels to be visible, set the color to match 2173the rest of the ground. </p> 2174 2175<p>The output image size will by default be the same as the input image. This 2176means that if the part of the distorted image falls outside the viewed area of 2177the 'distorted space', those parts is clipped and lost. However if you use 2178the plus form of the operator (<a href="#distort" >+distort</a>) the operator 2179will attempt (if possible) to show the whole of the distorted image, while 2180retaining a correct 'virtual canvas' offset, for image layering. This offset 2181may need to be removed using <a href="#repage" >+repage</a>, to remove if it 2182is unwanted. </p> 2183 2184<p>You can alternatively specify a special "<kbd><a href="#set" >-set</a> 2185option:distort:viewport {geometry_string}</kbd>" setting which will specify 2186the size and the offset of the generated 'viewport' image of the distorted 2187image space.</p> 2188 2189<p>Adding a "<kbd><a href="#set" >-set</a> option:distort:scale 2190{scale_factor}</kbd>" will scale the output image (viewport or otherwise) by 2191that factor without changing the viewed contents of the distorted image. This 2192can be used either for 'super-sampling' the image for a higher quality result, 2193or for panning and zooming around the image (with appropriate viewport 2194changes, or post-distort cropping and resizing). </p> 2195 2196<p>Setting <a href="#verbose" >-verbose</a> setting, will cause <a 2197href="#distort" >-distort</a> to attempt to output the internal coefficients, 2198and the <a href="#fx" >-fx</a> equivalent to the distortion, for expert study, 2199and debugging purposes. This many not be available for all distorts. </p> 2200 2201<p>Affine rotations and shears (such as '<kbd>SRT</kbd>' distortion), tend to 2202produce a cleaner result that the equivalent <a href="#rotate" >-rotate</a> 2203and/or <a href="#shear" >-shear</a> operation, with more control of due to the 2204above settings. It is algorithmically slower however, though that may not be 2205the case in ImageMagick's implementation. </p> 2206 2207 2208<div style="margin: auto;"> 2209 <h4><a name="dither" id="dither"></a>-dither <em class="arg">method</em></h4> 2210</div> 2211 2212<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> 2213 2214<p>Dithering places two or more colors in neighboring pixels so that to the eye a closer approximation of the images original color is reproduced. This reduces the number of colors needed to reproduce the image but at the cost of a lower level pattern of colors. Error diffusion dithers can use any set of colors (generated or user defined) to an image. </p> 2215 2216<p>Dithering is turned on by default, to turn it off use the plus form of the 2217setting, <a href="#dither">+dither</a>. This will also also render PostScript 2218without text or graphic aliasing. Disabling dithering often (but not always) 2219leads to faster process, a smaller number of colors, but more cartoon like 2220image coloring. Generally resulting in 'color banding' effects in areas with 2221color gradients. </p> 2222 2223<p>The color reduction operators <a href="#colors">-colors</a>, <a 2224href="#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> 2225 2226<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> 2227 2228 2229<div style="margin: auto;"> 2230 <h4><a name="draw" id="draw"></a>-draw <em class="arg">string</em></h4> 2231</div> 2232 2233<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> 2234 2235<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> 2236 2237<p>The shape primitives:</p> 2238 2239<pre class="text"> 2240 point x,y 2241 line x0,y0 x1,y1 2242 rectangle x0,y0 x1,y1 2243 roundRectangle x0,y0 x1,y1 wc,hc 2244 arc x0,y0 x1,y1 a0,a1 2245 ellipse x0,y0 rx,ry a0,a1 2246 circle x0,y0 x1,y1 2247 polyline x0,y0 ... xn,yn 2248 polygon x0,y0 ... xn,yn 2249 bezier x0,y0 ... xn,yn 2250 path path specification 2251 image operator x0,y0 w,h filename 2252</pre> 2253 2254<p>The text primitive:</p> 2255 2256<pre class="text"> 2257 text x0,y0 string 2258</pre> 2259<p>The text gravity primitive:</p> 2260 2261<pre class="text"> 2262 gravity NorthWest, North, NorthEast, West, Center, 2263 East, SouthWest, South, or SouthEast 2264</pre> 2265 2266<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> 2267 2268<p>The transformation primitives:</p> 2269 2270<pre class="text"> 2271 rotate degrees 2272 translate dx,dy 2273 scale sx,sy 2274 skewX degrees 2275 skewY degrees 2276</pre> 2277 2278<p>The pixel operation primitives:</p> 2279 2280<pre class="text"> 2281 color x0,y0 method 2282 matte x0,y0 method 2283</pre> 2284 2285<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> 2286 2287<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> 2288 2289<p>A <kbd>line</kbd> primitive requires a start point and end point.</p> 2290 2291<p>A <kbd>rectangle</kbd> primitive is specified by the pair of points at the upper left and lower right corners.</p> 2292 2293<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> 2294 2295<p>The <kbd>circle</kbd> primitive makes a disk (filled) or circle (unfilled). Give the center and any point on the perimeter (boundary).</p> 2296 2297<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> 2298 2299<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> 2300 2301<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>. 2302</p> 2303 2304<p>A <em>coordinate</em> is a pair of integers separated by a space or optional comma. </p> 2305 2306<p>As an example, to define a circle centered at 100,100 that extends to 150,150 use:</p> 2307 2308<p class="crtsnip"> 2309 -draw 'circle 100,100 150,150' 2310</p> 2311 2312<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 2313draw 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> 2314 2315<p class="crtsnip"> 2316 -draw 'bezier 20,50 45,100 45,0 70,50' 2317</p> 2318<p class="crtsnip"> 2319 -draw 'bezier 70,50 95,100 95,0 120,50' 2320</p> 2321 2322 2323<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> 2324 2325<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> 2326 2327<p class="crtsnip"> 2328 -draw 'image SrcOver 100,100 225,225 image.jpg' 2329</p> 2330 2331<p>You can use 0,0 for the image size, which means to use the actual 2332dimensions found in the image header. Otherwise, it is scaled to the given 2333dimensions. See <a href="/www/compose.html">Alpha Compositing</a> for 2334a detailed discussion of alpha composition methods that are available. </p> 2335 2336<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> 2337 2338<p>For example, the following annotates the image with <kbd>Works like magick!</kbd> for an image titled <kbd>bird.miff</kbd>. </p> 2339 2340<p class="crtsnip"> 2341 -draw 'text 100,100 "Works like magick!"' 2342</p> 2343 2344<p>See the <a href="#annotate">-annotate</a> option for another convenient way to annotate an image with text.</p> 2345 2346<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> 2347 2348<p>The <kbd>translate</kbd> primitive translates subsequent shape and text primitives.</p> 2349 2350<p>The <kbd>scale</kbd> primitive scales them.</p> 2351 2352<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> 2353 2354<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 2355matrix.</p> 2356 2357<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> 2358 2359<pre class="text"> 2360 point 2361 replace 2362 floodfill 2363 filltoborder 2364 reset 2365</pre> 2366 2367<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> 2368 2369<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> 2370 2371<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> 2372 2373<p>Strings that begin with a number must be quoted (e.g. use '1.png' rather than 1.png).</p> 2374 2375<p>Drawing primitives conform to the <a href="/www/magick-vector-graphics.html">Magick Vector Graphics</a> format.</p> 2376 2377 2378<div style="margin: auto;"> 2379 <h4><a name="edge" id="edge"></a>-edge <em class="arg">radius</em></h4> 2380</div> 2381 2382<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> 2383 2384<div style="margin: auto;"> 2385 <h4><a name="emboss" id="emboss"></a>-emboss <em class="arg">radius</em></h4> 2386</div> 2387 2388<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> 2389 2390<div style="margin: auto;"> 2391 <h4><a name="encipher" id="encipher"></a>-encipher <em class="arg">filename</em></h4> 2392</div> 2393 2394<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> 2395 2396<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p> 2397 2398<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p> 2399 2400 2401 2402<div style="margin: auto;"> 2403 <h4><a name="encoding" id="encoding"></a>-encoding <em class="arg">type</em></h4> 2404</div> 2405 2406<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> 2407 2408<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> 2409 2410<div style="margin: auto;"> 2411 <h4><a name="endian" id="endian"></a>-endian <em class="arg">type</em></h4> 2412</div> 2413 2414<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> 2415 2416<p>To print a complete list of endian types, use the <a href="#list">-list endian</a> option.</p> 2417 2418<p>Use <a href="#endian">+endian</a> to revert to unspecified endianness.</p> 2419 2420 2421<div style="margin: auto;"> 2422 <h4><a name="enhance" id="enhance"></a>-enhance</h4> 2423</div> 2424 2425<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> 2426 2427 2428<div style="margin: auto;"> 2429 <h4><a name="equalize" id="equalize"></a>-equalize</h4> 2430</div> 2431 2432<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> 2433 2434<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> 2435 2436<p>For example using HSL, we have: ... <kbd>-colorspace HSL -channel lightness -equalize -colorspace RGB</kbd> ...</p> 2437 2438<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> 2439 2440<div style="margin: auto;"> 2441 <h4><a name="evaluate" id="evaluate"></a>-evaluate <em class="arg">operator value</em></h4> 2442</div> 2443 2444<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> 2445 2446<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> 2447 2448<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> 2449 2450<table class="doc"> 2451 <col width="25%" /> 2452 <col width="75%" /> 2453 <thead> 2454 <tr> 2455 <th><em class="arg">operator</em></th> 2456 <th>Summary (see further below for details)</th> 2457 </tr> 2458 </thead> 2459 <tbody> 2460 2461 <tr><td>Abs </td> <td>Add <em class="arg">value</em> to pixels and return absolute value. </td></tr> 2462 <tr><td>Add </td> <td>Add <em class="arg">value</em> to pixels. </td></tr> 2463 <tr><td>AddModulus </td> <td>Add <em class="arg">value</em> to pixels modulo <em class="QR">QuantumRange</em>.</td></tr> 2464 <tr><td>And </td> <td>Binary AND of pixels with <em class="arg">value</em>.</td></tr> 2465 <tr><td>Cos, Cosine </td> <td>Apply cosine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr> 2466 <tr><td>Divide </td> <td>Divide pixels by <em class="arg">value</em>.</td></tr> 2467 <tr><td>Exp </td> <td>base-e exponential function</td></tr> 2468 <tr><td>Exponential </td> <td>base-e exponential function</td></tr> 2469 <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> 2470 <tr><td>Log </td> <td>Apply scaled logarithm to normalized pixels.</td></tr> 2471 <tr><td>Max </td> <td>Clip pixels at lower bound <em class="arg">value</em>.</td></tr> 2472 <tr><td>Mean </td> <td>Add the <em class="arg">value</em> and divide by 2.</td></tr> 2473 <tr><td>Min </td> <td>Clip pixels at upper bound <em class="arg">value</em>.</td></tr> 2474 <tr><td>Multiply </td> <td>Multiply pixels by <em class="arg">value</em>.</td></tr> 2475 <tr><td>Or </td> <td>Binary OR of pixels with <em class="arg">value</em>.</td></tr> 2476 <tr><td>Pow </td> <td>Raise normalized pixels to the power <em class="arg">value</em>.</td></tr> 2477 <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> 2478 <tr><td>Set </td> <td>Set pixel equal to <em class="arg">value</em>.</td></tr> 2479 <tr><td>Sin, Sine </td> <td>Apply sine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr> 2480 <tr><td>Subtract </td> <td>Subtract <em class="arg">value</em> from pixels.</td></tr> 2481 <tr><td>Xor </td> <td>Binary XOR of pixels with <em class="arg">value.</em></td></tr> 2482 2483 <tr><td> </td></tr> 2484 2485 <tr><td>Gaussian-noise</td></tr> 2486 <tr><td>Impulse-noise</td></tr> 2487 <tr><td>Laplacian-noise</td></tr> 2488 <tr><td>Multiplicative-noise</td> <td>(These are equivalent to the corresponding <a href="#noise" >-noise</a> operators.)</td></tr> 2489 <tr><td>PoissonNoise</td></tr> 2490 <tr><td>Uniform-noise</td></tr> 2491 2492 <tr><td> </td></tr> 2493 2494 <tr><td>Threshold </td> <td>Threshold pixels larger than <em class="arg">value</em>.</td></tr> 2495 <tr><td>ThresholdBlack </td> <td>Threshold pixels to zero values equal to or below <em class="arg">value</em>.</td></tr> 2496 <tr><td>ThresholdWhite </td> <td>Threshold pixels to maximum values above <em class="arg">value</em>. </td></tr> 2497 </tbody> 2498 </table> 2499 2500<p>The specified functions are applied only to each previously set <a 2501href="#channel" >-channel</a> in the image. If necessary, the results of the 2502calculations are truncated (clipped) to fit in the interval [0, <em 2503class="QR">QuantumRange</em>]. The transparency channel of the image is 2504represented as a 'alpha' values (0 = fully transparent), so, for example, a 2505<kbd>Divide</kbd> by 2 of the alpha channel will make the image 2506semi-transparent. Append the percent symbol '<kbd>%</kbd>' to specify a value 2507as a percentage of the <em class="QR">QuantumRange</em>.</p> 2508 2509<p>To print a complete list of <a href="#evaluate">-evaluate</a> operators, use 2510<a href="#list">-list evaluate</a>.</p> 2511 2512<p>The results of the <kbd>Add</kbd>, <kbd>Subtract</kbd> and 2513<kbd>Multiply</kbd> methods can also be achieved using either the <a 2514href="#level" >-level</a> or the <a href="#level" >+level</a> operator, with 2515appropriate argument, to linearly modify the overall range of color values. 2516Please note, however, that <a href="#level" >-level</a> treats transparency as 2517'matte' values (0 = opaque), while <a href="#level" >-evaluate</a> works with 2518'alpha' values.</p> 2519 2520<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> 2521 2522<p><kbd>Exp or Exponential</kbd> has been added as of ImageMagick 6.6.5-1 and works on normalized pixel values. The <em class="arg">value</em> used with <kbd>Exp</kbd> should be negative so as to produce a decaying exponential function. Non-negative values will always produce results larger unity and thus outside the interval [0, <em class="QR">QuantumRange</em>]. The formula is expressed below. </p> 2523 2524 <div style="text-align:center;"> 2525 exp(<em class="arg">value</em> × <b><em>u</em></b>) 2526 </div> 2527 2528<p> If the input image is squared, for example, using <a 2529href="#-function" >-function polynomial "2 0 0"</a>, then a decaying Gaussian function will be the result.</p> 2530 2531<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> 2532 2533 <div style="text-align:center;"> 2534 log(<em class="arg">value</em> × <b><em>u</em></b> + 1) / log(<em class="arg">value</em> + 1) 2535 </div> 2536 2537<p><kbd>Pow</kbd> has been added as of ImageMagick 6.4.1-9, and works on 2538normalized pixel values. Note that <kbd>Pow</kbd> is related to the <a 2539href="#gamma" >-gamma</a> operator. For example, <b>-gamma 2</b> is equivalent 2540to <b>-evaluate pow 0.5</b>, i.e., a 'square root' function. The value used 2541with <a href="#gamma" >-gamma</a> is simply the reciprocal of the value used 2542with <kbd>Pow</kbd>.</p> 2543 2544<p><kbd>Cosine</kbd> and <kbd>Sine</kbd> was added as of IM v6.4.8-8 and 2545converts the image values into a value according to a (co)sine wave function. 2546The synonyms <kbd>Cos</kbd> and <kbd>Sin</kbd> may also be used. The output 2547is biased 50% and normalized by 50% so as to fit in the respective color value 2548range. The <em class="arg">value</em> scaling of the <em>period</em> of the 2549function (its frequency), and thus determines the number of 'waves' that will 2550be generated over the input color range. For example, if the <em 2551class="arg">value</em> is 1, the effective period is simply the <em 2552class="QR">QuantumRange</em>; but if the <em class="arg">value</em> is 2, 2553then the effective period is the <em>half</em> the <em 2554class="QR">QuantumRange</em>. 2555 2556 <div style="text-align:center;"> 2557 0.5 + 0.5 × cos(2 π <b><em>u</em></b> × <em class="arg">value</em>). 2558 </div> 2559 2560See also the <a href="#function" >-function</a> operator, which is a 2561multi-value version of evaluate. </P> 2562 2563<div style="margin: auto;"> 2564 <h4><a name="evaluate-sequence" id="evaluate-sequence"></a>-evaluate-sequence <em class="arg">operator</em></h4> 2565</div> 2566 2567<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Alter channel pixels by evaluating an arithmetic, relational, or logical expression over a sequence of images.</td><td style='text-align:right;'></td></tr></table> 2568 2569<div style="margin: auto;"> 2570 <h4><a name="extent" id="extent"></a>-extent <em class="arg">geometry</em></h4> 2571</div> 2572 2573<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> 2574 2575<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> 2576 2577<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> 2578 2579<div style="margin: auto;"> 2580 <h4><a name="extract" id="extract"></a>-extract <em class="arg">geometry</em></h4> 2581</div> 2582 2583<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> 2584 2585<p>This option is most useful for extracting a subregion of a very large raw image. Note that these two commands are equivalent:</p> 2586 2587<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 -extract 640x480+1280+960 \ <br/> image.rgb image.png</span><span class='crtout'></span><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 'image.rgb[640x480+1280+960]' \ <br/> image.rgb image.png</span></p><p>If you omit the offsets, as in</p> 2588 2589<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 -extract 640x480 \ <br/> image.rgb image.png</span></p> 2590<p>the image is <em>resized</em> to the specified dimensions instead, 2591equivalent to:</p> 2592 2593<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 -resize 640x480 image.rgb image.png</span></p> 2594<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> 2595 2596<div style="margin: auto;"> 2597 <h4><a name="family" id="family"></a>-family <em class="arg">fontFamily</em></h4> 2598</div> 2599 2600<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> 2601 2602<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). 2603</p> 2604 2605<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>. 2606</p> 2607 2608<div style="margin: auto;"> 2609 <h4><a name="features" id="features"></a>-features <em class="arg">distance</em></h4> 2610</div> 2611 2612<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> 2613 2614<div style="margin: auto;"> 2615 <h4><a name="fft" id="fft"></a>-fft</h4> 2616</div> 2617 2618<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> 2619 2620<p>This option is new as of ImageMagick 6.5.4-3 (and now working for Windows users in ImageMagick 6.6.0-9). It transforms an image from the normal (spatial) domain to the frequency domain. In the frequency domain, an image is represented as a superposition of complex sinusoidal waves of varying amplitudes. The image x and y coordinates are the possible frequencies along the x and y directions, respectively, and the pixel intensity values are complex numbers that correspond to the sinusoidal wave amplitudes. See for example, <a href="http://en.wikipedia.org/wiki/Fourier_transform" target="_blank">Fourier Transform</a>, <a href="http://en.wikipedia.org/wiki/DFT" target="_blank">Discrete Fourier Transform</a> and <a href="http://en.wikipedia.org/wiki/FFT" target="_blank">Fast Fourier Transform</a>.</p> 2621 2622<p>A single image name is provided as output for this option. However, the output result will have two components. It is either a two-frame image or two separate images, depending upon whether the image format specified supports multi-frame images. The reason that we get a dual output result is because the frequency domain represents an image using complex numbers, which cannot be visualized directly. Therefore, the complex values are automagically separated into a two-component image representation. The first component is the magnitude of the complex number and the second is the phase of the complex number. See for example, <a href="http://en.wikipedia.org/wiki/Complex_numbers" target="_blank">Complex Numbers</a>.<p> 2623 2624<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> 2625 2626<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -fft fft_image.miff</span></p> 2627<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> 2628 2629<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -fft fft_image.png</span></p> 2630<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> 2631 2632<p>The input image can be any size, but if not square and even-dimensioned, it is padded automagically to the larger of the width or height of the input image and to an even number of pixels. The padding will occur at the bottom and/or right sides of the input image. The resulting output magnitude and phase images is square at this size. The kind of padding relies on the <a href="#virtual-pixel">-virtual-pixel</a> setting.</p> 2633 2634<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> 2635 2636<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert fft_image.miff[0] -contrast-stretch 0 \ <br /> 2637 -evaluate log 1000 fft_image_spectrum.png</span></p> 2638<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> 2639 2640<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#fft">-fft</a>. 2641 2642<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> 2643 2644<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> 2645 2646<p>The real and imaginary component images resulting from <a href="#fft">+fft</a> is also square, even dimensioned images due to the same padding that was discussed above for the magnitude and phase component images.</a> 2647 2648<p>See the discussion on HDRI implementations of ImageMagick on the page 2649<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. 2650</p> 2651 2652 2653<div style="margin: auto;"> 2654 <h4><a name="fill" id="fill"></a>-fill <em class="arg">color</em></h4> 2655</div> 2656 2657<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> 2658 2659<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> 2660 2661<p>Enclose the color specification in quotation marks to prevent the "#" or the parentheses from being interpreted by your shell.</p> 2662 2663<p>For example,</p> 2664 2665<p class="crtsnip"> 2666 -fill blue 2667</p> 2668<p class="crtsnip"> 2669 -fill "#ddddff" 2670</p> 2671<p class="crtsnip"> 2672 -fill "rgb(255,255,255)" 2673</p> 2674 2675<p>See <a href="#draw">-draw</a> for further details.</p> 2676 2677<p>To print a complete list of color names, use the <a href="#list">-list color</a> option.</p> 2678 2679<div style="margin: auto;"> 2680 <h4><a name="filter" id="filter"></a>-filter <em class="arg">type</em></h4> 2681</div> 2682 2683<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Use this <em class="arg">type</em> of filter when resizing or 2684distorting an image.</td><td style='text-align:right;'></td></tr></table> 2685 2686<p>Use this option to affect the resizing operation of an image during 2687operations such as <a href="#resize">-resize</a> and <a href="#distort" 2688>-distort</a>. For example you can use a simple resize filter such as:</p> 2689 2690<pre class="text"> 2691 Point Hermite Cubic 2692 Box Gaussian Catrom 2693 Triangle Quadratic Mitchell 2694</pre> 2695 2696<p>The <kbd>Bessel</kbd> and <kbd>Sinc</kbd> filter is also provided (as well 2697as a faster <kbd>SincFast</kbd> equivalent form). However these filters are 2698generally useless on their own as they are infinite filters that are being 2699clipped to the filters support size. Their direct use is not recommended 2700except via expert settings (see below). </p> 2701 2702Instead these special filter functions are typically windowed by a windowing 2703function that the <a href="#filter" >-filter</a> setting defines. That is 2704using these functions will define a 'Windowed' filter, appropriate to the 2705operator involved. Windowed filters include: </p> 2706 2707<pre class="text"> 2708 Lanczos Hamming Parzen 2709 Blackman Kaiser Welsh 2710 Hanning Bartlett Bohman 2711</pre> 2712 2713<p>Also one special self-windowing filter is also provided 2714<kbd>Lagrange</kbd>, which will automagically re-adjust its function depending 2715on the current 'support' or 'lobes' expert settings (see below).</p> 2716 2717<p>If you do not select a filter with this option, the filter defaults to 2718<kbd>Mitchell</kbd> for a colormapped image, a image with a matte channel, or 2719if the image is enlarged. Otherwise the filter default to 2720<kbd>Lanczos</kbd>.</p> 2721 2722<p>To print a complete list of resize filters, use the <a href="#list">-list 2723filter</a> option.</p> 2724 2725<p>You can modify how the filter behaves as it scales your image through the 2726use of these expert settings (see also <a href="#define" >-define</a> and <a 2727href="#set" >-set</a>):-</p> 2728 2729<dl class="doc"> 2730<dt>-define filter:blur=<em>factor</em></dt> 2731<dd>Scale the X axis of the filter (and its window). Use > 1.0 for 2732 blurry or < 1.0 for sharp. This should only be used with Gaussian and 2733 Gaussian-like filters simple filters, or you may not get the expected 2734 results. </dd> 2735 2736<dt>-define filter:support=<em>radius</em></dt> 2737<dd>Set the filter support radius. Defines how large the filter should be and 2738 thus directly defines how slow the filtered resampling process is. All 2739 filters have a default 'prefered' support size. Some filters like 2740 <kbd>Lagrange</kbd> and windowed filters adjust themselves depending on 2741 this value. With simple filters this value either does nothing (but slow 2742 the resampling), or will clip the filter function in a detrimental way. 2743 </dd> 2744 2745<dt>-define filter:lobes=<em>count</em></dt> 2746<dd>Set the number of lobes to use for the Sinc/Bessel filter. This an 2747 alternative way of specifying the 'support' range of the filter, that is 2748 designed to be more suited to windowed filters, especially when used for 2749 image distorts.</dd> 2750 2751<dt>-define filter:b=<em>b-spline_factor</em></dt> 2752<dt>-define filter:c=<em>keys_alpha_factor</em></dt> 2753<dd>Redefine the values used for cubic filters such as <kbd>Cubic</kbd>, 2754 <kbd>Catrom</kbd>, <kbd>Mitchel</kbd>, and <kbd>Hermite</kbd>, as well as 2755 the <kbd>Parzen</kbd> Sinc windowing function. If only one of the values 2756 are defined, the other is set so as to generate a 'Keys' type cubic 2757 filter. Values meaning was defined by a research paper by 2758 Mitchell-Netravali. 2759 2760<dt>-define filter:filter=<em>filter_function</em></dt> 2761<dd>Use this function directly as the scaling filter. This will allow 2762 you to directly use a windowing filter such as <kbd>Blackman</kbd>, 2763 rather than as its normal usage as a windowing function for 'Sinc' or 2764 'Bessel' functions. If defined, no windowing function is used, unless the 2765 following expert setting is also defined.</dd> 2766 2767<dt>-define filter:window=<em>filter_function</em></dt> 2768<dd>The IIR (infinite impulse response) filters <kbd>Bessel</kbd> and 2769 <kbd>Sinc</kbd> are windowed (brought down to zero over the defined 2770 support range) with the given filter. This allows you to specify a filter 2771 function that is not normally used as a windowing function, such as 2772 <kbd>Box</kbd>, (which effectively turns off the windowing function), 2773 to window a <kbd>Sinc</kbd>, or the function the previous setting defined. 2774 </dd> 2775 2776<dt>-define filter:verbose=<em>1</em></dt> 2777<dd>This causes IM to print information on the final internal filter 2778 selection to standard output. This includes a commented header on the 2779 filter settings being used, and data allowing the filter weights to be 2780 easily graphed. </dd> 2781 2782<dd>Note however that some filters are internally defined in terms of other 2783 filters. The <kbd>Lanczos</kbd> filter for example is defined in terms of 2784 a <kbd>SincFast</kbd> windowed <kbd>SincFast</kbd> filter, while 2785 <kbd>Mitchell</kbd> is defined as a <kbd>Cubic</kbd> filter with specific 2786 'B' and 'C' settings. </dd> 2787 2788</dl> 2789 2790<p>For example, to get a 8 lobe Bessel windowed Bessel filter:</p> 2791 2792<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -filter bessel \ <br/> 2793 -set filter:window=bessel -set filter:lobes=8 \ <br/> 2794 -resize 150% image.jpg</span></p> 2795<p>Or a raw un-windowed Sinc filter with 4 lobes:</p> 2796 2797<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -set filter:filter=sinc -set filter:lobes=4 \ <br/> 2798 -resize 150% image.jpg</span></p> 2799<p>Note that the use of expert options (except for 'blur' with simple resize 2800filters, and 'verbose' for viewing the internal filter selection), are 2801provided for image processing experts who have studied and understood how 2802resize filters work. Without this knowledge, and an understanding of the 2803definition of the actual filters involved, using expert settings are more 2804likely to be detrimental to your image resizing.</p> 2805 2806 2807<div style="margin: auto;"> 2808 <h4><a name="flatten" id="flatten"></a>-flatten</h4> 2809</div> 2810 2811<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> 2812 2813 2814<div style="margin: auto;"> 2815 <h4><a name="flip" id="flip"></a>-flip</h4> 2816</div> 2817 2818<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> 2819 2820<p>reflect the scanlines in the vertical direction.</p> 2821 2822<div style="margin: auto;"> 2823 <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> 2824</div> 2825 2826<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> 2827 2828<div style="margin: auto;"> 2829 <h4><a name="flop" id="flop"></a>-flop</h4> 2830</div> 2831 2832<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> 2833 2834<p>reflect the scanlines in the horizontal direction.</p> 2835 2836 2837<div style="margin: auto;"> 2838 <h4><a name="font" id="font"></a>-font <em class="arg">name</em></h4> 2839</div> 2840 2841<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> 2842 2843<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> 2844 2845<p>In addition to the fonts specified by the above pre-defined list, you can 2846also specify a font from a specific source. For example <kbd>Arial.ttf</kbd> 2847is a TrueType font file, <kbd>ps:helvetica</kbd> is PostScript font, and 2848<kbd>x:fixed</kbd> is X11 font.</p> 2849 2850<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> 2851 2852 2853<div style="margin: auto;"> 2854 <h4><a name="foreground" id="foreground"></a>-foreground <em class="arg">color</em></h4> 2855</div> 2856 2857<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> 2858 2859<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 2860 2861<p>The default foreground color is black.</p> 2862 2863<div style="margin: auto;"> 2864 <h4><a name="format" id="format"></a>-format <em class="arg">type</em></h4> 2865</div> 2866 2867<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> 2868 2869<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> 2870 2871<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> 2872 2873<div style="margin: auto;"> 2874 <h4><a name="format_identify_" id="format_identify_"></a>-format <em class="arg">string</em></h4> 2875</div> 2876 2877<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> 2878 2879<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> 2880 2881<div style="margin: auto;"> 2882 <h4><a name="frame" id="frame"></a>-frame <em class="arg">geometry</em></h4> 2883</div> 2884 2885<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> 2886 2887<p>The color of the border is specified with the <a href="#mattecolor" 2888>-mattecolor</a> command line option. </p> 2889 2890<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 2891class="arg">geometry</em> argument indicates the amount of extra width and 2892height that is added to the dimensions of the image. If no offsets are given 2893in the <em class="arg">geometry</em> argument, then the border added is 2894a solid color. Offsets <em>x</em> and <em>y</em>, if present, specify that 2895the width and height of the border is partitioned to form an outer bevel of 2896thickness <em>x</em> pixels and an inner bevel of thickness 2897<em>y</em> pixels. Negative offsets make no sense as frame arguments. 2898</p> 2899 2900<p>The <a href="#frame">-frame</a> option is affected by the current <a 2901href="#compose">-compose</a> setting and assumes that this is using the default 2902'<kbd>Over</kbd>' composition method. It generates a image of the appropriate 2903size with the current <a href="#bordercolor">-bordercolor</a> setting, and then 2904draws the frame of four distinct colors close to the current <a 2905href="#mattecolor">-mattecolor</a>. The original image is then overlaid onto 2906center of this image. This means that with the default compose method of 2907'<kbd>Over</kbd>' any transparent parts may be replaced by the current <a 2908href="#bordercolor">-bordercolor</a> setting.</p> 2909 2910<p>The image composition is not 2911affected by the <a href="#gravity">-gravity</a> option.</p> 2912 2913 2914<div style="margin: auto;"> 2915 <h4><a name="frame_import_" id="frame_import_"></a>-frame</h4> 2916</div> 2917 2918<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> 2919 2920<div style="margin: auto;"> 2921 <h4><a name="function" id="function"></a>-function <em class="arg">function</em> <em class="arg">parameters</em></h4> 2922</div> 2923 2924<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> 2925 2926<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> 2927 2928<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> 2929 2930<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> 2931 2932<pre class="text"> 2933 Polynomial 2934 Sinusoid 2935 Arcsin 2936 Arctan 2937</pre> 2938 2939<p>To print a complete list of <a href="#function">-function</a> operators, use <a href="#list">-list function</a>. Descriptions follow.</p> 2940 2941<dl class="doc"> 2942<dt><kbd>Polynomial</kbd></dt> 2943<dd> 2944<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> 2945 2946<div style="text-align: center"> 2947 -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> 2948</div> 2949 2950<p>will invoke a polynomial function given by</p> 2951 2952<div style="text-align: center"> 2953 <em>a</em><sub><em>n</em></sub> <b><em>u</em></b><sup><em>n</em></sup> + 2954 <em>a</em><sub><em>n</em>-1</sub> <b><em>u</em></b><sup><em>n</em>-1</sup> + 2955 ··· <em>a</em><sub>1</sub> <b><em>u</em></b> + <em>a</em><sub>0</sub>, 2956</div> 2957 2958<p>where <b><em>u</em></b> is pixel's original normalized channel value.</p> 2959 2960<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> 2961 2962<table class="doc"> 2963 <col width="35%" /> 2964 <col width="35%" /> 2965 <col width="30%" /> 2966 <tr> 2967 <td>-evaluate Set <em class="arg">value</em> </td> 2968 <td>-function Polynomial <em class="arg">value</em></td> 2969 <td>(Constant functions; set <em class="arg">value</em>×100% gray when channels are RGB.)</td> 2970 </tr> 2971 <tr> 2972 <td>-evaluate Add <em class="arg">value</em> </td> 2973 <td>-function Polynomial 1,<em class="arg">value</em></td> 2974 </tr> 2975 <tr> 2976 <td>-evaluate Subtract <em class="arg">value</em> </td> 2977 <td>-function Polynomial 1,−<em class="arg">value</em></td> 2978 </tr> 2979 <tr> 2980 <td>-evaluate Multiply <em class="arg">value</em> </td> 2981 <td>-function Polynomial <em class="arg">value</em>,0</td> 2982 </tr> 2983 <tr> 2984 <td>+level black% x white%</td> 2985 <td>-function Polynomial A,B</td> 2986 <td>(Reduce contrast. Here, A=(white-black)/100 and B=black/100.)</td> 2987 </tr> 2988</table> 2989 2990<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> 2991</dd> 2992 2993<dt><kbd>Sinusoid</kbd></dt> 2994<dd> 2995<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> 2996 2997<div style="text-align: center"> 2998 -function <kbd>Sinusoid</kbd> <em class="arg">freq</em>,[<em class="arg">phase</em>,[<em class="arg">amp</em>,[<em class="arg">bias</em>]]] 2999</div> 3000 3001<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> 3002 3003<div style="text-align: center"> 3004<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> 3005</div> 3006 3007<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> 3008 3009<p class="crtsnip"> 3010 -function Sinusoid 3,-90,.2,.7 3011</p> 3012 3013<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> 3014 3015<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> 3016 3017<table class="doc"> 3018 <tr> 3019 <td>-evaluate Sin <em class="arg">freq</em> </td> 3020 <td>-function Sinusoid <em class="arg">freq</em>,0 </td> 3021 </tr> 3022 <tr> 3023 <td>-evaluate Cos <em class="arg">freq</em> </td> 3024 <td>-function Sinusoid <em class="arg">freq</em>,90 </td> 3025 </tr> 3026</table> 3027</dd> 3028 3029<dt><kbd>ArcSin</kbd></dt> 3030<dd> 3031<p>The <kbd>ArcSin</kbd> function generates the inverse curve of a Sinusoid, 3032and can be used to generate cylindrical distortion and displacement maps. 3033The curve can be adjusted relative to both the input values and output range 3034of values. 3035 3036<div style="text-align: center"> 3037 -function <kbd>ArcSin</kbd> <em class="arg">width</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]] 3038</div> 3039 3040<p>with all values given in terms of noramlize color values (0.0 for black, 30411.0 for white). Defaulting to values covering the full range from 0.0 to 1.0 3042for bout input (<em class="arg">width</em>), and output (<em 3043class="arg">width</em>) values. '<code>1.0,0.5,1.0,0.5</code>' </p> 3044 3045<div style="text-align: center"> 3046<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> 3047</div> 3048 3049</dd> 3050 3051<dt><kbd>ArcTan</kbd></dt> 3052<dd> 3053<p>The <kbd>ArcTan</kbd> function generates a curve that smooth crosses from 3054limit values at infinities, though a center using the given slope value. 3055All these values can be adjusted via the arguments. 3056 3057<div style="text-align: center"> 3058 -function <kbd>ArcTan</kbd> <em class="arg">slope</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]] 3059</div> 3060 3061<p>Defaulting to '<code>1.0,0.5,1.0,0.5</code>'. 3062</p> 3063 3064<div style="text-align: center"> 3065<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> 3066</div> 3067 3068</dd> 3069 3070</dl> 3071 3072 3073<div style="margin: auto;"> 3074 <h4><a name="fuzz" id="fuzz"></a>-fuzz <em class="arg">distance</em>{<em class="arg">%</em>}</h4> 3075</div> 3076 3077<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> 3078 3079<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> 3080 3081<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> 3082 3083 3084<div style="margin: auto;"> 3085 <h4><a name="fx" id="fx"></a>-fx <em class="arg">expression</em></h4> 3086</div> 3087 3088<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> 3089 3090<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> 3091 3092<p>See <a href="/www/fx.html">FX, The Special Effects Image Operator</a> for a detailed discussion of this option.</p> 3093 3094 3095<div style="margin: auto;"> 3096 <h4><a name="gamma" id="gamma"></a>-gamma <em class="arg">value</em></h4> 3097</div> 3098 3099<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> 3100 3101<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> 3102 3103<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> 3104 3105<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> 3106 3107<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> 3108 3109<p>Note that gamma adjustments are also available via the <a href="#level">-level</a> operator.</p> 3110 3111<div style="margin: auto;"> 3112 <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> 3113</div> 3114 3115<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> 3116 3117<p>Convolve the image with a Gaussian or normal distribution using the given 3118<em class="arg" >Sigma</em> value. The formula is:</p> 3119 3120<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="/images/gaussian-blur.png"/> 3121</div> 3122 3123<p>The <em class="arg" >Sigma</em> value is the important argument, and 3124determines the actual amount of bluring that will take place. </p> 3125 3126<p>The <em class="arg" >Radius</em> is only used to determine the size of the 3127array which will hold the calculated gaussian distribution. It should be an 3128integer. If not given, or set to zero, IM will calculate the largest possible 3129radius that will provide meaningful results for the Gaussian distribution. 3130</p> 3131 3132<p>The larger the <em class="arg" >Radius</em> the radius the slower the 3133operation is. However too small a <em class="arg" >Radius</em>, and sever 3134aliasing effects may result. As a guideline, <em class="arg" >Radius</em> 3135should be at least twice the <em class="arg" >Sigma</em> value, though three 3136times will produce a more accurite result. </p> 3137 3138<p>This differs from the faster <a href="#blur">-blur</a> operator in that a 3139full 2-dimensional convolution is used to generate the weighted average of the 3140neighboring pixels. </p> 3141 3142<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 3143pixels which are outside the image proper are blurred into the final result. 3144</p> 3145 3146 3147<div style="margin: auto;"> 3148 <h4><a name="geometry" id="geometry"></a>-geometry <em class="arg">geometry</em></h4> 3149</div> 3150 3151<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> 3152 3153<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> 3154 3155<div style="margin: auto;"> 3156 <h4><a name="gravity" id="gravity"></a>-gravity <em class="arg">type</em></h4> 3157</div> 3158 3159<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> 3160 3161<p>Choices include: <kbd>NorthWest</kbd>, <kbd>North</kbd>, <kbd>NorthEast</kbd>, 3162<kbd>West</kbd>, <kbd>Center</kbd>, <kbd>East</kbd>, <kbd>SouthWest</kbd>, 3163<kbd>South</kbd>, <kbd>SouthEast</kbd>. Use <a href="#list">-list gravity</a> to get a complete 3164list of <a href="#gravity">-gravity</a> settings available in your ImageMagick 3165installation.</p> 3166 3167<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> 3168 3169<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> 3170 3171<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> 3172 3173<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -gravity Center -region 10x10-40+20 \ <br/> -negate output.png</span></p> 3174<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> 3175 3176<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> 3177 3178 3179<div style="margin: auto;"> 3180 <h4><a name="green-primary" id="green-primary"></a>-green-primary <em class="arg">x,y</em></h4> 3181</div> 3182 3183<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> 3184 3185 3186<div style="margin: auto;"> 3187 <h4><a name="hald-clut" id="hald-clut"></a>-hald-clut</h4> 3188</div> 3189 3190<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> 3191 3192<p>A Hald color lookup table is a 3-dimensional color cube mapped to 2 3193dimensions. Create it with the <kbd>HALD:</kbd> prefix (e.g. HALD:8). You 3194can apply any color transformation to the Hald image and then use this option 3195to apply the transform to the image. </p> 3196 3197<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png hald.png -hald-clut transform.png</span></p> 3198<p>This option provides a convenient method for you to use Gimp or Photoshop 3199to make color corrections to the Hald CLUT image and subsequently apply them 3200to multiple images using an ImageMagick script. </p> 3201 3202<p>Note that the representation is only of the normal RGB color space and that 3203the whole color value triplet is used for the interpolated lookup of the 3204represented Hald color cube image. Because of this the operation is not <a 3205href="#channel" >-channel</a> setting effected, nor can it adjust or modify an 3206images transparency or alpha/matte channel.</p> 3207 3208<p>See also <a href="#clut" >-clut</a> which provides color value replacement 3209of the individual color channels, usally involving a simplier gray-scale 3210image. E.g: gray-scale to color replacement, or modification by a histogram 3211mapping. </p> 3212 3213 3214<div style="margin: auto;"> 3215 <h4><a name="help" id="help"></a>-help</h4> 3216</div> 3217 3218<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> 3219 3220<div style="margin: auto;"> 3221 <h4><a name="highlight-color" id="highlight-color"></a>-highlight-color <em class="arg">color</em></h4> 3222</div> 3223 3224<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> 3225 3226<div style="margin: auto;"> 3227 <h4><a name="iconGeometry" id="iconGeometry"></a>-iconGeometry <em class="arg">geometry</em></h4> 3228</div> 3229 3230<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> 3231 3232<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> 3233 3234<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> 3235 3236<div style="margin: auto;"> 3237 <h4><a name="iconic" id="iconic"></a>-iconic</h4> 3238</div> 3239 3240<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> 3241 3242<div style="margin: auto;"> 3243 <h4><a name="identify" id="identify"></a>-identify</h4> 3244</div> 3245 3246<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> 3247 3248<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> 3249 3250<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> 3251 3252<p>If <a href="#verbose">-verbose</a> precedes this option, copious 3253amounts of image properties are displayed including image statistics, profiles, 3254image histogram, and others.</p> 3255 3256<div style="margin: auto;"> 3257 <h4><a name="ift" id="ift"></a>-ift</h4> 3258</div> 3259 3260<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> 3261 3262<p>This option is new as of ImageMagick 6.5.4-3 (and now working for Windows users in ImageMagick 6.6.0-9). It transforms a pair of magnitude and phase images from the frequency domain to a single image in the normal or spatial domain. See for example, <a href="http://en.wikipedia.org/wiki/Fourier_transform" target="_blank">Fourier Transform</a>, <a href="http://en.wikipedia.org/wiki/DFT" target="_blank">Discrete Fourier Transform</a> and <a href="http://en.wikipedia.org/wiki/FFT" target="_blank">Fast Fourier Transform</a>.</p> 3263 3264<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> 3265 3266<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert fft_image.miff -ift fft_image_ift.png</span></p> 3267<p>or</p> 3268 3269<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> 3270 3271<p>The resulting image may need to be cropped due to padding introduced when the original image, prior to the <a href="#fft">-fft</a> or <a href="#fft">+fft</a>, was not square or even dimensioned. Any padding is at the right and/or bottom sides of the image. 3272 3273<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#ift">-ift</a>. 3274 3275<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. 3276 3277<div style="margin: auto;"> 3278 <h4><a name="immutable" id="immutable"></a>-immutable</h4> 3279</div> 3280 3281<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> 3282 3283<div style="margin: auto;"> 3284 <h4><a name="implode" id="implode"></a>-implode <em class="arg">factor</em></h4> 3285</div> 3286 3287<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> 3288 3289<div style="margin: auto;"> 3290 <h4><a name="insert" id="insert"></a>-insert <em class="arg">index</em></h4> 3291</div> 3292 3293<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> 3294 3295<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> 3296 3297<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> 3298 3299<div style="margin: auto;"> 3300 <h4><a name="intent" id="intent"></a>-intent <em class="arg">type</em></h4> 3301</div> 3302 3303<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> 3304 3305<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> 3306 3307<p>The default intent is undefined.</p> 3308 3309<p>To print a complete list of rendering intents, use <a href="#list">-list intent</a>.</p> 3310 3311<div style="margin: auto;"> 3312 <h4><a name="interlace" id="interlace"></a>-interlace <em class="arg">type</em></h4> 3313</div> 3314 3315<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> 3316 3317<p>Choose from:</p> 3318 3319<pre class="text"> 3320 none 3321 line 3322 plane 3323 partition 3324 JPEG 3325 GIF 3326 PNG 3327</pre> 3328 3329<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> 3330 3331<p><kbd>None</kbd> means do not interlace (RGBRGBRGBRGBRGBRGB...),</p> 3332 3333<p><kbd>Line</kbd> uses scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...), and.</p> 3334 3335<p><kbd>Plane</kbd> uses plane interlacing (RRRRRR...GGGGGG...BBBBBB...).</p> 3336 3337<p><kbd>Partition</kbd> is like plane except the different planes are saved to individual files (e.g. image.R, 3338image.G, and image.B).</p> 3339 3340<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> 3341image.</p> 3342 3343<p>To print a complete list of interlacing schemes, use <a href="#list">-list interlace</a>.</p> 3344 3345<div style="margin: auto;"> 3346 <h4><a name="interpolate" id="interpolate"></a>-interpolate <em class="arg">type</em></h4> 3347</div> 3348 3349<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> 3350 3351<p>When looking up the color of a pixel using a non-integer floating point 3352value, you typically fall in between the pixel colors defined by the source 3353image. This setting determines how the color is determined from the colors of 3354the pixels surrounding that point. That is how to determine the color of a 3355point that falls between two, or even four different colored pixels. </p> 3356 3357<pre class="text"> 3358 integer: The color of the top-left pixel (floor function) 3359 nearest-neighbor: The nearest pixel to the lookup point (rounded function) 3360 average: The average color of the surrounding four pixels 3361 bilinear A double linear interpolation of pixels (the default) 3362 mesh Divide area into two flat triangular interpolations 3363 bicubic Fitted bicubic-spines of surrounding 16 pixels 3364 spline Direct spline curves (colors are blurred) 3365 filter Use resize <a href="#filter">-filter</a> settings 3366</pre> 3367 3368<p>This most important for distortion operators such as <a href="#distort" 3369>-distort</a>, <a href="#implode" >-implode</a>, <a href="#transform" 3370>-transform</a> and <a href="#fx" >-fx</a>. </p> 3371 3372<p>To print a complete list of interpolation methods, use <a href="#list">-list interpolate</a>.</p> 3373 3374<p>See also <a href="#virtual-pixel" >-virtual-pixel</a>, for control of the 3375lookup for positions outside the boundaries of the image. </p> 3376 3377 3378<div style="margin: auto;"> 3379 <h4><a name="interline-spacing" id="interline-spacing"></a>-interline-spacing <em class="arg">value</em></h4> 3380</div> 3381 3382<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> 3383 3384<div style="margin: auto;"> 3385 <h4><a name="interword-spacing" id="interword-spacing"></a>-interword-spacing <em class="arg">value</em></h4> 3386</div> 3387 3388<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> 3389 3390<div style="margin: auto;"> 3391 <h4><a name="kerning" id="kerning"></a>-kerning <em class="arg">value</em></h4> 3392</div> 3393 3394<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> 3395 3396<div style="margin: auto;"> 3397 <h4><a name="label" id="label"></a>-label <em class="arg">name</em></h4> 3398</div> 3399 3400<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> 3401 3402<p>Use this option to assign a specific label to the image, as it is read in 3403or created. You can use the <a href="#set" >-set</a> operation to re-assign 3404a the labels of images already read in. Image formats such as TIFF, PNG, 3405MIFF, supports saving the label information with the image.</p> 3406 3407<p>When saving an image to a <em class="arg">PostScript</em> file, any label 3408assigned to an image is used as a header string to print above the postscript 3409image. </p> 3410 3411<p>You can include the image filename, type, width, height, or other image 3412attribute by embedding special format character. See <a href="/www/escape.html">Format and Print Image 3413Properties</a> for details of the percent escape codes.</p> 3414 3415<p>For example,</p> 3416 3417<p class="crtsnip"> 3418 -label "%m:%f %wx%h" bird.miff 3419</p> 3420 3421<p>assigns an image label of <kbd>MIFF:bird.miff 512x480</kbd> to the 3422"<kbd>bird.miff</kbd>" image and whose width is 512 and height is 480, as it 3423is read in. If a <a href="#label">+label</a> option was used instead, any 3424existing label present in the image would be used. You can remove all labels 3425from an image by assigning the empty string. </p> 3426 3427<p>A label is not drawn on the image, but is embedded in the image datastream 3428via <em>Label</em> tag or similar mechanism. If you want the label to be 3429visible on the image itself, use the <a href="#draw">-draw</a> option, or 3430during the final processing in the creation of a image montage.</p> 3431 3432<p>If the first character of <em class="arg">string</em> is <em 3433class="arg">@</em>, the image label is read from a file titled by the 3434remaining characters in the string. Labels in a file are literal, no embedded 3435formatting characters are recognized.</p> 3436 3437 3438<div style="margin: auto;"> 3439 <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> 3440</div> 3441 3442<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> 3443 3444<p>Adaptively threshold each pixel based on the value of pixels in a 3445surrounding window. If the current pixel is lighter than this average plus 3446the optional <kbd>offset</kbd>, then it is made white, otherwise it is made 3447black. Small variations in pixel values such as found in scanned documents 3448can be ignored if offset is positive. A negative offset will make it more 3449sensitive to those small variations. </p> 3450 3451<p>This is commonly used to threshold images with an uneven background. It is 3452based on the assumption that average color of the small window is the 3453the local background color, from which to separate the forground color. </p> 3454 3455 3456<div style="margin: auto;"> 3457 <h4><a name="layers" id="layers"></a>-layers <em class="arg">method</em></h4> 3458</div> 3459 3460<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> 3461 3462<p>Perform various image operation methods to a ordered sequence of images 3463which may represent either a set of overlaid 'image layers', a GIF disposal 3464animation, or a fully-'coalesced' animation sequence. </p> 3465 3466<table class="doc"> 3467 <tbody> 3468 <tr valign="top"> 3469 <th align="left" style="width: 8%">Method</th> 3470 <th align="left">Description</th> 3471 </tr> 3472 3473 <tr valign="top"> 3474 <td valign="top">compare-any</td> 3475 <td valign="top">Crop the second and later frames to the smallest rectangle 3476 that contains all the differences between the two images. No GIF <a 3477 href="#dispose" >-dispose</a> methods are taken into account. </td> 3478 </tr> 3479 3480 <tr><td></td><td>This exactly the same as the <a href="#deconstruct" 3481 >-deconstruct</a> operator, and does not preserve animations normal 3482 working, especially when animation used layer disposal methods such as 3483 '<kbd>Previous</kbd>' or '<kbd>Background</kbd>'. </td> 3484 </tr> 3485 3486 <tr valign="top"> 3487 <td valign="top">compare-clear</td> 3488 <td valign="top">As '<kbd>compare-any</kbd>' but crop to the bounds of any 3489 opaque pixels which become transparent in the second frame. That is the 3490 smallest image needed to mask or erase pixels for the next frame. </td> 3491 </tr> 3492 3493 <tr valign="top"> 3494 <td valign="top">compare-overlay</td> 3495 <td valign="top">As '<kbd>compare-any</kbd>' but crop to pixels that add 3496 extra color to the next image, as a result of overlaying color pixels. 3497 That is the smallest single overlaid image to add or change colors. </td> 3498 </tr> 3499 3500 <tr><td></td><td>This can be used with the <a href="#compose" >-compose</a> alpha 3501 composition method '<kbd>change-mask</kbd>', to reduce the image to 3502 just the pixels that need to be overlaid. </td> 3503 </tr> 3504 3505 <tr valign="top"> 3506 <td valign="top">coalesce</td> 3507 <td valign="top">Equivalent to a call to the <a href="#coalesce" 3508 >-coalesce</a> operator. Apply the layer disposal methods set in the 3509 current image sequence to form a fully defined animation sequence, as 3510 it should be displayed. Effectively converting a GIF animation into a 3511 'film strip'-like animation. </td> 3512 </tr> 3513 3514 <tr valign="top"> 3515 <td valign="top">composite</td> 3516 <td valign="top">Alpha Composition of two image lists, separated by a 3517 "<kbd>null:</kbd>" image, with the destination image list first, and 3518 the source images last. An image from each list are composited 3519 together until one list is finished. The separator image and source 3520 image lists are removed. </td> 3521 </tr> 3522 3523 3524 <tr><td></td> 3525 <td>The <a href="#geometry" >-geometry</a> offset is adjusted according 3526 to <a href="#gravity" >-gravity</a> in accordance of the virtual 3527 canvas size of the first image in each list. Unlike a normal <a 3528 href="#composite" >-composite</a> operation, the canvas offset is also 3529 added to the final composite positioning of each image. </td> </tr> 3530 3531 <tr><td></td> 3532 <td>If one of the image lists only contains one image, that image is 3533 applied to all the images in the other image list, regardless of which 3534 list it is. In this case it is the image meta-data of the list which 3535 preserved. </td> 3536 </tr> 3537 3538 3539 <tr valign="top"> 3540 <td valign="top">dispose</td> 3541 <td valign="top">This like '<kbd>coalesce</kbd>' but shows the look of 3542 the animation after the layer disposal method has been applied, before 3543 the next sub-frame image is overlaid. That is the 'dispose' image that 3544 results from the application of the GIF <a href="#dispose" 3545 >-dispose</a> method. This allows you to check what 3546 is going wrong with a particular animation you may be developing. 3547 </td> 3548 </tr> 3549 3550 <tr valign="top"> 3551 <td valign="top">flatten</td> 3552 <td valign="top">Create a canvas the size of the first images virtual 3553 canvas using the current <a href="#background" >-background</a> color, 3554 and <a href="#compose" >-compose</a> each image in turn onto that 3555 canvas. Images falling outside that canvas is clipped. Final 3556 image will have a zero virtual canvas offset. </td> 3557 </tr> 3558 3559 <tr><td></td> 3560 <td>This usally used as one of the final 'image layering' operations 3561 overlaying all the prepared image layers into a final image. </td> 3562 </tr> 3563 3564 <tr><td></td> 3565 <td>For a single image this method can also be used to fillout a virtual 3566 canvas with real pixels, or to underlay a opaque color to remove 3567 transparency from an image.</td> 3568 </tr> 3569 3570 3571 <tr valign="top"> 3572 <td valign="top">merge</td> 3573 <td valign="top">As 'flatten' method but merging all the given image 3574 layers into a new layer image just large enough to hold all the image 3575 without clipping or extra space. The new images virtual offset will 3576 prevere the position of the new layer, even if this offset is 3577 negative. the virtual canvas size of the first image is preserved. 3578 </td> 3579 </tr> 3580 3581 <tr><td></td><td>Caution is advised when handling image layers with negative offsets 3582 as few image file formats handle them correctly. </td> 3583 </tr> 3584 3585 <tr valign="top"> 3586 <td valign="top">mosaic</td> 3587 <td valign="top">As 'flatten' method but expanding the initial canvas size 3588 of the first image so as to hold all the image layers. However as a 3589 virtual canvas is 'locked' to the origin, by definition, image layers 3590 with a negative offsets will still be clipped by the top and left 3591 edges.</td> 3592 </tr> 3593 3594 <tr><td></td><td>This method is commonly used to layout individual image using various 3595 offset but without knowing the final canvas size. The resulting image 3596 will, like 'flatten' not have any virtual offset, so can be saved to 3597 any image file format. </td> 3598 </tr> 3599 3600 3601 <tr valign="top"> 3602 <td valign="top">optimize</td> 3603 <td valign="top">Optimize a coalesced animation, into GIF animation using 3604 a number of general techniques. This currently a short cut to 3605 apply both the '<kbd>optimize-frame</kbd>', and 3606 '<kbd>optimize-transparency</kbd>' methods but may be expanded to 3607 include other optimization methods as they are developed. </td> 3608 </tr> 3609 3610 <tr valign="top"> 3611 <td valign="top">optimize-frame</td> 3612 <td valign="top">Optimize a coalesced animation, into GIF animation by 3613 reducing the number of pixels per frame as much as possible by 3614 attempting to pick the best layer disposal method to use, while ensuring 3615 the result will continue to animate properly. </td> 3616 </tr> 3617 3618 <tr><td></td><td> There is no guarantee that the best optimization is found. But 3619 then no reasonably fast GIF optimization algorithm can do this. 3620 However this does seem to do better than most other GIF frame 3621 optimizers seen. </td> 3622 </tr> 3623 3624 <tr valign="top"> 3625 <td valign="top">optimize-plus</td> 3626 <td valign="top">As '<kbd>optimize-frame</kbd>' but attempt to improve the 3627 overall optimization by adding extra frames to the animation, without 3628 changing the final look or timing of the animation. The frames are 3629 added to attempt to separate the clearing of pixels from the 3630 overlaying of new additional pixels from one animation frame to the 3631 next. If this does not improve the optimization (for the next frame 3632 only), it will fall back to the results of the previous normal 3633 '<kbd>optimize-frame</kbd>' technique. </td> 3634 </tr> 3635 3636 <tr><td></td><td>There is the possibility that the change in the disposal style will 3637 result in a worsening in the optimization of later frames, though this 3638 is unlikely. In other words there no guarantee that it is better than 3639 the normal '<kbd>optimize-frame</kbd>' technique. For some animations 3640 however you can get a vast improvement in the final animation size. </td> 3641 </tr> 3642 3643 <tr valign="top"> 3644 <td valign="top">optimize-transparency</td> 3645 <td valign="top">Given a GIF animation, replace any pixel in the sub-frame 3646 overlay images with transparency, if it does not change the resulting 3647 animation by more than the current <a href="#fuzz" >-fuzz</a> factor. 3648 </td> 3649 </tr> 3650 3651 <tr><td></td><td>This should allow a existing frame optimized GIF animation to compress 3652 into a smaller file size due to larger areas of one (transparent) 3653 color rather than a pattern of multiple colors repeating the current 3654 disposed image of the last frame. </td> 3655 </tr> 3656 3657 <tr valign="top"> 3658 <td valign="top">remove-dups</td> 3659 <td valign="top">Remove (and merge time delays) of duplicate consecutive 3660 images, so as to simplify layer overlays of coalesced animations. 3661 </td> 3662 </tr> 3663 3664 <tr><td></td><td>Usually this a result of using a constant time delay across the 3665 whole animation, or after a larger animation was split into smaller 3666 sub-animations. The duplicate frames could also have been used as 3667 part of some frame optimization methods. </td> 3668 </tr> 3669 3670 <tr valign="top"> 3671 <td valign="top">remove-zero</td> 3672 <td valign="top">Remove any image with a zero time delay, unless ALL the 3673 images have a zero time delay (and is not a proper timed animation, a 3674 warning is then issued). </td> 3675 </tr> 3676 3677 <tr><td></td><td>In a GIF animation, such images are usually frames which provide 3678 partial intermediary updates between the frames that are actually 3679 displayed to users. These frames are usally added for improved frame 3680 optimization in GIF animations. </td> 3681 </tr> 3682 3683 <tr valign="top"> 3684 <td valign="top">trim-bounds</td> 3685 <td valign="top">Find the bounds of all the images in the current 3686 image sequence, then adjust the offsets so all images are contained on 3687 a minimal positive canvas. None of the image data is modified, only 3688 there virtual canvas size and offset. The all the image is given 3689 the same canvas size, and and will have a positive offset, but will 3690 remain in the same position relative to each other. As a result of the 3691 minimal canvas size at least one image will touch every edge of that 3692 canvas. The image data however may be transparent. 3693 </td> 3694 </tr> 3695 3696 </tbody> 3697</table> 3698 3699<p>To print a complete list of layer types, use <a href="#list">-list layers</a>.</p> 3700 3701<p>The operators <a href="#coalesce" >-coalesce</a>, <a href="#deconstruct" 3702>-deconstruct</a>, <a href="#flatten" >-flatten</a>, and <a href="#mosaic" 3703>-mosaic</a> are only aliases for the above methods. Also see <a 3704href="#page" >-page</a>, <a href="#repage" >-repage</a> operators, the <a 3705href="#compose" >-compose</a> setting, and the GIF <a href="#dispose" 3706>-dispose</a> and <a href="#delay" >-delay</a> settings. </p> 3707 3708 3709<div style="margin: auto;"> 3710 <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> 3711</div> 3712 3713<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> 3714 3715<p>Given one, two or three values delimited with commas: black-point, 3716white-point, gamma (for example: 10,250,1.0 or 2%,98%,0.5). The black and 3717white points range from 0 to <em class="QR">QuantumRange</em>, or from 0 to 100%; if the white 3718point is omitted it is set to (<em class="QR">QuantumRange</em> - black_point), so as to center 3719contrast changes. If a <kbd>%</kbd> sign is present anywhere in the string, 3720both black and white points are percentages of the full color range. Gamma 3721will do a <a href="#gamma">-gamma</a> adjustment of the values. If it is 3722omitted, the default of 1.0 (no gamma correction) is assumed.</p> 3723 3724<p>In normal usage (<kbd>-level</kbd>) the image values are stretched so that 3725the given '<kbd>black_point</kbd>' value in the original image is set to 3726zero (or black), while the given '<kbd>white_point</kbd>' value is set to 3727<em class="QR">QuantumRange</em> (or white). This provides you with direct contrast adjustments 3728to the image. The '<kbd>gamma</kbd>' of the resulting image will then be 3729adjusted. </p> 3730 3731<p>From ImageMagick v6.4.1-9 using the plus form of the operator (<kbd>+level</kbd>) or 3732adding the special '!' flag anywhere in the argument list, will cause the 3733operator to do the reverse of the level adjustment. That is a zero, or 3734<em class="QR">QuantumRange</em> value (black, and white, resp.) in the original image, is 3735adjusted to the given level values, allowing you to de-contrast, or compress 3736the channel values within the image. The '<kbd>gamma</kbd>' is adjusted before the level adjustment to de-contrast the image is made. </p> 3737 3738<p>Only the channels defined by the current <a href="#channel">-channel</a> 3739setting are adjusted (defaults to RGB color channels only), allowing you to 3740limit the effect of this operator. </p> 3741 3742<p>Please note that the transparency channel is treated as 'matte' 3743values (0 is opaque) and not as 'alpha' values (0 is transparent).</p> 3744 3745 3746<div style="margin: auto;"> 3747 <h4><a name="level-colors" id="level-colors"></a>-level-colors {<em 3748 class="arg">black_color</em>}{,}{<em class="arg">white_color</em>}</h4> 3749</div> 3750 3751<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>adjust the level of an image using the provided dash separated colors.</td><td style='text-align:right;'></td></tr></table> 3752 3753<p>This function is exactly like <a href="#level">-level</a>, except that the 3754value value for each color channel is determined by the 3755'<kbd>black_color</kbd>' and '<kbd>white_color</kbd>' colors given (as 3756described under the <a href="#fill">-fill</a> option). </p> 3757 3758<p>This effectually means the colors provided to <kbd>-level-colors</kbd> 3759is mapped to become 'black' and 'white' respectively, with all the other 3760colors linearly adjusted (or clipped) to match that change. Each channel is 3761adjusted separately using the channel values of the colors specified. </p> 3762 3763<p>On the other hand the plus form of the operator (<kbd>+level-colors</kbd>) 3764will map the image color 'black' and 'white' to the given colors 3765respectively, resulting in a gradient (de-contrasting) tint of the image to 3766those colors. This can also be used to convert a plain gray-scale image into a 3767one using the gradient of colors specified. </p> 3768 3769<p>By supplying a single color with a comma separator either before or after 3770that color, will just replace the respective 'black' or 'white' point 3771respectively. But if no comma separator is provided, the given color is 3772used for both the black and white color points, making the operator either 3773threshold the images around that color (- form) or set all colors to that 3774color (+ form). </p> 3775 3776 3777<div style="margin: auto;"> 3778 <h4><a name="limit" id="limit"></a>-limit <em class="arg">type value</em></h4> 3779</div> 3780 3781<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> 3782 3783<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> 3784 3785<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> 3786 3787<p class="crtsnip"> 3788 -limit memory 32MiB -limit map 64MiB 3789</p> 3790 3791<p>Use <a href="#list">-list resource</a> to list the current limits. For example, our system shows these limits:</p> 3792 3793<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 3794------------------------------------------------------------------------------ 3795 768 12.404GB 8.6642GiB 23.104GiB 18.446744EB 8 unlimited</pre> 3796</span></p> 3797<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> 3798 3799<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> 3800 3801<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> 3802 3803<p class="crtsnip"> 3804-limit area 10mb 3805</p> 3806 3807<p>Now whenever a large image is processed, the pixels are automagically cached to disk instead of memory. This of course implies that large images typically process very slowly, simply because pixel processing in memory can be an order of magnitude faster than on disk. Because your web site users might inadvertently upload a huge image to process, you should set a disk limit as well:</p> 3808 3809<p class="crtsnip"> 3810-limit area 10mb -limit disk 500mb 3811</p> 3812 3813<p>Here ImageMagick stops processing if an image requires more than 500MB of disk storage.</p> 3814 3815<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> 3816 3817<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. 3818</p> 3819 3820<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. 3821</p> 3822 3823<div style="margin: auto;"> 3824 <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> 3825</div> 3826 3827<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> 3828 3829<p>This is very similar to <a href="#contrast-stretch" >-contrast-stretch</a>, 3830and uses a 'histogram bin' to determine the range of color values that needs to 3831be stretched. However it then stretchs those colors using the <a 3832href="#level" >-level</a> operator.</p> 3833 3834<p>As such while the initial determination may have 'binning' round off 3835effects, the image colors are stretched mathematically, rather than using the 3836histogram bins. This makes the operator more accurate. </p> 3837 3838<p>note however that a <a href="#linear-stretch" >-linear-stretch</a> of 3839'<kbd>0</kbd>' does nothing, while a value of '<kbd>1</kbd>' does a near 3840perfect stretch of the color range. </p> 3841 3842<p>See also <a href="#auto-level" >-auto-level</a> for a 'perfect' 3843normalization of mathematical images. </p> 3844 3845<p>This operator is under review for re-development. </p> 3846 3847 3848<div style="margin: auto;"> 3849 <h4><a name="linewidth" id="linewidth"></a>-linewidth</h4> 3850</div> 3851 3852<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> 3853 3854<div style="margin: auto;"> 3855 <h4><a name="liquid-rescale" id="liquid-rescale"></a>-liquid-rescale <em class="arg">geometry</em></h4> 3856</div> 3857 3858<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> 3859 3860<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> 3861 3862<div style="margin: auto;"> 3863 <h4><a name="list" id="list"></a>-list <em class="arg">type</em></h4> 3864</div> 3865 3866<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> 3867 3868<pre class="text"> 3869 Align 3870 Alpha 3871 Boolean 3872 Channel 3873 Class 3874 ClipPath 3875 Coder 3876 Color 3877 Colorspace 3878 Command 3879 Compose 3880 Compress 3881 Configure 3882 DataType 3883 Debug 3884 Decoration 3885 Delegate 3886 Direction 3887 Dispose 3888 Distort 3889 Dither 3890 Endian 3891 Evaluate 3892 FillRule 3893 Filter 3894 Font 3895 Format 3896 Function 3897 Gravity 3898 ImageList 3899 Intent 3900 Interlace 3901 Interpolate 3902 Kernel 3903 Layers 3904 LineCap 3905 LineJoin 3906 List 3907 Locale 3908 LogEvent 3909 Log 3910 Magic 3911 Method 3912 Metric 3913 Mime 3914 Mode 3915 Morphology 3916 Module 3917 Noise 3918 Orientation 3919 Policy 3920 PolicyDomain 3921 PolicyRights 3922 Preview 3923 Primitive 3924 QuantumFormat 3925 Resource 3926 SparseColor 3927 Storage 3928 Stretch 3929 Style 3930 Threshold 3931 Type 3932 Units 3933 Validate 3934 VirtualPixel 3935</pre> 3936 3937<p>These lists vary depending on your version of ImageMagick. Use "<kbd>-list 3938list</kbd>" to get a complete listing of all the "<kbd>-list</kbd>" arguments 3939available:</p> 3940 3941<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>identify -list list</span></p> 3942<div style="margin: auto;"> 3943 <h4><a name="log" id="log"></a>-log <em class="arg">string</em></h4> 3944</div> 3945 3946<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> 3947 3948<p>This option specifies the format for the log printed when the <a 3949href="#debug">-debug</a> option is active.</p> 3950 3951<p>You can display the following components by embedding special format 3952characters:</p> 3953 3954<pre class="text"> 3955 %d domain 3956 %e event 3957 %f function 3958 %l line 3959 %m module 3960 %p process ID 3961 %r real CPU time 3962 %t wall clock time 3963 %u user CPU time 3964 %% percent sign 3965 \n newline 3966 \r carriage return 3967</pre> 3968 3969<p>For example:</p> 3970 3971<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> 3972<p>The default behavior is to print all of the components.</p> 3973 3974<div style="margin: auto;"> 3975 <h4><a name="loop" id="loop"></a>-loop <em class="arg">iterations</em></h4> 3976</div> 3977 3978<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> 3979 3980<p>Set iterations to zero to repeat the animation an infinite number of times, 3981otherwise the animation repeats itself up to <em class="arg">iterations</em> 3982times.</p> 3983 3984<div style="margin: auto;"> 3985 <h4><a name="lowlight-color" id="lowlight-color"></a>-lowlight-color <em class="arg">color</em></h4> 3986</div> 3987 3988<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> 3989 3990<div style="margin: auto;"> 3991 <h4><a name="magnify" id="magnify"></a>-magnify <em class="arg">factor</em></h4> 3992</div> 3993 3994<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> 3995 3996 3997<div style="margin: auto;"> 3998 <h4><a name="map" id="map"></a>-map <em class="arg">type</em></h4> 3999</div> 4000 4001<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> 4002 4003<p>Choose from these <em class="arg">Standard Colormap</em> types:</p> 4004 4005<pre class="text"> 4006 best 4007 default 4008 gray 4009 red 4010 green 4011 blue 4012</pre> 4013 4014<p>The <em class="arg">X server</em> must support the <em class="arg">Standard 4015Colormap</em> you choose, otherwise an error occurs. Use <kbd>list</kbd> as 4016the type and <kbd>display</kbd> searches the list of colormap types in 4017<kbd>top-to-bottom</kbd> order until one is located. See <em 4018class="arg">xstdcmap(1)</em> for one way of creating Standard Colormaps.</p> 4019 4020 4021<div style="margin: auto;"> 4022 <h4><a name="map_stream_" id="map_stream_"></a>-map <em class="arg">components</em></h4> 4023</div> 4024 4025<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> 4026 4027<p>Here are the valid components of a map:</p> 4028 4029<pre class="text"> 4030 r red pixel component 4031 g green pixel component 4032 b blue pixel component 4033 a alpha pixel component (0 is transparent) 4034 o opacity pixel component (0 is opaque) 4035 i grayscale intensity pixel component 4036 c cyan pixel component 4037 m magenta pixel component 4038 y yellow pixel component 4039 k black pixel component 4040 p pad component (always 0) 4041</pre> 4042 4043<p>You can specify as many of these components as needed in any order (e.g. 4044bgr). The components can repeat as well (e.g. rgbr).</p> 4045 4046 4047<div style="margin: auto;"> 4048 <h4><a name="mask" id="mask"></a>-mask 4049<em class="arg">filename</em></h4> 4050</div> 4051 4052<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> 4053 4054<p>Use <a href="#mask">+mask</a> to remove the image mask.</p> 4055 4056<div style="margin: auto;"> 4057 <h4><a name="mattecolor" id="mattecolor"></a>-mattecolor <em class="arg">color</em></h4> 4058</div> 4059 4060<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> 4061 4062<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 4063 4064<p>The default matte color is <kbd>#BDBDBD</kbd>, <span 4065style="background-color: #bdbdbd;">this shade of gray</span>.</p> 4066 4067<div style="margin: auto;"> 4068 <h4><a name="maximum" id="maximum"></a>-maximum</h4> 4069</div> 4070 4071<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>return the maximum intensity of an image sequence.</td><td style='text-align:right;'></td></tr></table> 4072 4073<div style="margin: auto;"> 4074 <h4><a name="median" id="median"></a>-median <em class="arg">radius</em></h4> 4075</div> 4076 4077<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> 4078 4079<div style="margin: auto;"> 4080 <h4><a name="metric" id="metric"></a>-metric <em class="arg">type</em></h4> 4081</div> 4082 4083<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> 4084 4085<p>Choose from:</p> 4086 4087<pre class="text"> 4088 AE absolute error count, number of different pixels (-fuzz effected) 4089 MAE mean absolute error (normalized), average channel error distance 4090 MEPP mean error per pixel (normalized mean error, normalized peak error) 4091 MSE mean error squared, average of the channel error squared 4092 PAE peak absolute (normalize peak absolute) 4093 PSNR peak signal to noise ratio 4094 RMSE root mean squared (normalized root mean squared) 4095</pre> 4096 4097<p>The '<kbd>AE</kbd>' or absolute count of pixels that are different, can be 4098controlled using a <a href="#fuzz" >-fuzz</a> factor to ignore pixels which 4099only changed by a small amount. The '<kbd>PAE</kbd>' can be used to find the 4100size of the <a href="#fuzz" >-fuzz</a> factor needed to make all pixels 4101'similar', while '<kbd>MAE</kbd>' can be used to find out the factor needed 4102for about half the pixels to be similar. </p> 4103 4104<p>The '<kbd>MEPP</kbd>' metric returns three different metrics 4105('<kbd>MAE</kbd>', '<kbd>MAE</kbd>' normalized, and '<kbd>PAE</kbd>' 4106normalized) from a single comparison run. </p> 4107 4108<p>To print a complete list of metrics, use the <a href="#list">-list 4109metrics</a> option.</p> 4110 4111 4112<div style="margin: auto;"> 4113 <h4><a name="minimum" id="minimum"></a>-minimum</h4> 4114</div> 4115 4116<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>return the minimum intensity of an image sequence.</td><td style='text-align:right;'></td></tr></table> 4117 4118 4119<div style="margin: auto;"> 4120 <h4><a name="mode" id="mode"></a>-mode <em class="arg">value</em></h4> 4121</div> 4122 4123<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> 4124 4125<p>Choose the <em class="arg">value</em> from these styles: <kbd>Frame, 4126Unframe, or Concatenate</kbd></p> 4127 4128<p>Use the <a href="#list" >-list</a> option with a '<kbd>Mode</kbd>' argument 4129for a list of <a href="#mode" >-mode</a> arguments available in your 4130ImageMagick installation.</p> 4131 4132 4133<div style="margin: auto;"> 4134 <h4><a name="modulate" id="modulate"></a>-modulate <em class="arg">brightness</em>[,<em class="arg">saturation</em>,<em class="arg">hue</em>]</h4> 4135</div> 4136 4137<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 4138class="arg">saturation</em>, and <em class="arg">hue</em> of an image.</td><td style='text-align:right;'></td></tr></table> 4139 4140<p>The arguments are given as a percentages of variation. A value of 100 means 4141no change, and any missing values are taken to mean 100.</p> 4142 4143<p>The <em class="arg">brightness</em> is a multiplier of the overall 4144brightness of the image, so 0 means pure black, 50 is half as bright, 200 is 4145twice as bright. To invert its meaning <a href="#negate">-negate</a> the image 4146before and after. </p> 4147 4148<p>The <em class="arg">saturation</em> controls the amount of color in an 4149image. For example, 0 produce a grayscale image, while a large value such as 4150200 produce a very colorful, 'cartoonish' color.</p> 4151 4152<p>The <em class="arg">hue</em> argument causes a "rotation" of the colors 4153within the image by the amount specified. For example, 50 results in 4154a counter-clockwise rotation of 90, mapping red shades to purple, and so on. 4155A value of either 0 or 200 results in a complete 180 degree rotation of the 4156image. Using a value of 300 is a 360 degree rotation resulting in no change to 4157the original image. </p> 4158 4159<p>For example, to increase the color brightness by 20% and decrease the color 4160saturation by 10% and leave the hue unchanged, use <a 4161href="#modulate">-modulate 120,90</a>.</p> 4162 4163<p>Use <a href="#set">-set</a> attribute of '<kbd 4164class="arg">option:modulate:colorspace</kbd>' to specify which colorspace to 4165modulate. Choose from <kbd>HSB</kbd>, <kbd>HSL</kbd> (the default), or 4166<kbd>HWB</kbd>. For example,</p> 4167 4168<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> 4169 4170<div style="margin: auto;"> 4171 <h4><a name="monitor" id="monitor"></a>-monitor</h4> 4172</div> 4173 4174<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> 4175 4176 4177<div style="margin: auto;"> 4178 <h4><a name="monochrome" id="monochrome"></a>-monochrome</h4> 4179</div> 4180 4181<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> 4182 4183 4184<div style="margin: auto;"> 4185 <h4><a name="morph" id="morph"></a>-morph <em class="arg">frames</em></h4> 4186</div> 4187 4188<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> 4189 4190<p>Both the image pixels and size are linearly interpolated to give the 4191appearance of a meta-morphosis from one image to the next, over all the images 4192in the current image list. The added images are the equivalent of a <a 4193href="#blend">-blend</a> composition. The <em class="arg">frames</em> 4194argument determine how many images to interpolate between each image. </p> 4195 4196 4197<div style="margin: auto;"> 4198 <h4><a name="morphology" id="morphology"></a>-morphology</h4> 4199 <h4><a name="morphology" id="morphology"></a>-morphology <em class="arg">method</em> <em class="arg">kernel</em></h4> 4200</div> 4201 4202<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> 4203 4204Until I get around to writing a option summary for this, see <A 4205HREF="http://www.imagemagick.org/Usage/morphology/" >IM Usage Examples, 4206Morphology</A>. </P> 4207 4208 4209<div style="margin: auto;"> 4210 <h4><a name="mosaic" id="mosaic"></a>-mosaic</h4> 4211</div> 4212 4213<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> 4214 4215 4216<div style="margin: auto;"> 4217 <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> 4218</div> 4219 4220<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> 4221 4222<p>Blur with the given radius, standard deviation (sigma), and angle. The 4223angle given is the angle toward which the image is blurred. That is the 4224direction people would consider the object is coming from. </p> 4225 4226<p>Note that the blur is not uniform distribution, giving the motion a 4227definite sense of direction of movement. </p> 4228 4229<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 4230pixels which are outside the image proper are blurred into the final result. 4231</p> 4232 4233<div style="margin: auto;"> 4234 <h4><a name="name" id="name"></a>-name</h4> 4235</div> 4236 4237<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> 4238<div style="margin: auto;"> 4239 <h4><a name="negate" id="negate"></a>-negate</h4> 4240</div> 4241 4242<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> 4243 4244<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> 4245 4246<div style="margin: auto;"> 4247 <h4><a name="noise" id="noise"></a>-noise <em class="arg">radius</em><br/> 4248 +noise <em class="arg">type</em></h4> 4249</div> 4250 4251<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> 4252 4253<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> 4254 4255<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> 4256 4257<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> 4258 4259<pre class="text"> 4260Gaussian 4261Impulse 4262Laplacian 4263Multiplicative 4264Poisson 4265Random 4266Uniform 4267</pre> 4268 4269<p>To print a complete list of noises, use the <a href="#list">-list noise</a> option.</p> 4270 4271<p>Also see the <a href="#evaluate">-evaluate</a> noise functions that allos 4272the use of a controlling value to specify teh amount of noise that should be 4273added to an image. </p> 4274 4275 4276<div style="margin: auto;"> 4277 <h4><a name="normalize" id="normalize"></a>-normalize</h4> 4278</div> 4279 4280<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> 4281 4282<p>The intensity values are stretched to cover the entire range of possible 4283values. While doing so, black-out at most <em>2%</em> of the pixels and 4284white-out at most <em>1%</em> of the pixels.</p> 4285 4286<p>Note that as of ImageMagick 6.4.7-0, <a href="#normalize" >-normalize</a> 4287is equivalent to <a href="#contrast-stretch" >-contrast-stretch 2%x1%</a>. 4288(Before this version, it was equivalent to <a href="#contrast-stretch" 4289>-contrast-stretch 2%x99%</a>).</p> 4290 4291<p>All the channels are normalized in concert by the came amount so as to 4292preserve color integrity, when the default <a href="#channel" >+channel</a> 4293setting is in use. Specifying any other <a href="#channel" >-channel</a> 4294setting will normalize the RGB channels independently.</p> 4295 4296<p>See <a href="#contrast-stretch" >-contrast-stretch</A> for more details. 4297Also see <a href="#auto-level" >-auto-level</a> for a 'perfect' normalization 4298that is better suited to mathematically generated images. </p> 4299 4300<p>This operator is under review for re-development. </p> 4301 4302 4303<div style="margin: auto;"> 4304 <h4><a name="ordered-dither" id="ordered-dither"></a>-ordered-dither <em class="arg">threshold_map</em>{,<em class="arg">level</em>...}</h4> 4305</div> 4306 4307<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 4308class="arg">threshold map</em> specified, and a uniform color map with the 4309given number of <em class="arg">levels</em> per color channel . </td><td style='text-align:right;'></td></tr></table> 4310 4311<p>You can choose from these standard threshold maps:</p> 4312 4313<pre class="text"> 4314 threshold 4315 checks 4316 o2x2 4317 o3x3 4318 o4x4 4319 o8x8 4320 h4x4a 4321 h6x6a 4322 h8x8a 4323 h4x4o 4324 h6x6o 4325 h8x8o 4326 h16x16o 4327</pre> 4328 4329<p>The '<kbd>o</kbd>' maps are ordered diffused pixel threshold maps, while the 4330'<kbd>h</kbd>' maps are halftone threshold maps which are either 'a' angled, or 4331'o' orthogonal. The '<kbd>checks</kbd>' produce a 3 level checkerbord dither 4332pattern. Or you can define your own <em class="arg" >threshold map</em> in a 4333personal or system "<kbd>thresholds.xml</kbd>" XML file. </p> 4334 4335<p>To print a complete list of threshold, use the <a href="#list" >-list 4336threshold</a> option.</p> 4337 4338<p>It is recommended that the <a href="#map" >+map</a> operator be used after 4339applying <a href="#ordered-dither" >-ordered-dither</a> to reduce the number of 4340colors an animated image sequence, to less that 256 colors. This ensures that 4341a common or global color table is used when saving the result to a color 4342limited file format such as GIF. </p> 4343 4344<p>Note that at this time the exact same threshold dithering map is used for 4345all color channels, no attempt is made to offset or rotate the map for 4346different channels is made, to create an offset printing effect. (possible 4347future expansion) </p> 4348 4349 4350<div style="margin: auto;"> 4351 <h4><a name="opaque" id="opaque"></a>-opaque <em class="arg">color</em></h4> 4352</div> 4353 4354<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> 4355 4356<p>The <em class="arg">color</em> argument is defined using the format 4357described under the <a href="#fill" >-fill</a> option. The <a href="#fuzz" 4358>-fuzz</a> setting can be used to match and replace colors similar to the one 4359given.</p> 4360 4361<p>Use <a href="#opaque">+opaque</a> to paint any pixel that does not match 4362the target color. </p> 4363 4364<p>The <a href="#transparent">-transparent</a> operator is exactly the same 4365as <a href="#opaque" >-opaque</a> but replaces the matching color with 4366transparency rather than the current <a href="#fill">-fill</a> color setting. 4367To ensure that it can do this it also ensures that the image has an alpha 4368channel enabled, as per "<kbd><a href="#alpha" >-alpha</a> set</kbd>", for 4369the new transparent colors, and does not require you to modify the <a 4370href="#channel">-channel</a> to enable alpha channel handling. </p> 4371 4372 4373<div style="margin: auto;"> 4374 <h4><a name="orient" id="orient"></a>-orient <em class="arg">image orientation</em></h4> 4375</div> 4376 4377<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> 4378 4379<p>Choose from these orientations:</p> 4380 4381<pre class="text"> 4382 bottom-left 4383 bottom-right 4384 left-bottom 4385 left-top 4386 right-bottom 4387 right-top 4388 top-left 4389 top-right 4390 undefined 4391</pre> 4392 4393<p>To print a complete list of orientations, use the <a href="#list" >-list 4394orientation</a> option.</p> 4395 4396 4397<div style="margin: auto;"> 4398 <h4><a name="page" id="page"></a>-page <em class="arg">geometry</em><br/> 4399 -page <em class="arg">media</em>[<em class="arg">offset</em>][{<em class="arg">^!<></em>}]<br/> 4400 +page 4401 </h4> 4402</div> 4403 4404<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> 4405 4406<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> 4407 4408<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> 4409 4410<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> 4411<table id="geometryTable" cellpadding="2" cellspacing="0" border="1" width="50%" style="margin-left: auto; margin-right: auto;"> 4412<thead> 4413 <tr valign="top"> 4414 <th align="center"><em class="arg">media</em></th> 4415 <th align="center"><em class="arg">width</em></th> 4416 <th align="center"><em class="arg">height</em></th> 4417 </tr> 4418</thead> 4419<tbody> 4420<tr><td align="left"> 11x17 </td> <td align="right"> 792</td> <td align="right"> 1224</td> </tr> 4421<tr><td align="left"> Ledger </td> <td align="right"> 1224</td> <td align="right"> 792</td> </tr> 4422<tr><td align="left"> Legal </td> <td align="right"> 612</td> <td align="right"> 1008</td> </tr> 4423<tr><td align="left"> Letter </td> <td align="right"> 612</td> <td align="right"> 792</td> </tr> 4424<tr><td align="left"> LetterSmall</td> <td align="right"> 612</td> <td align="right"> 792</td> </tr> 4425<tr><td align="left"> ArchE </td> <td align="right"> 2592</td> <td align="right"> 3456</td> </tr> 4426<tr><td align="left"> ArchD </td> <td align="right"> 1728</td> <td align="right"> 2592</td> </tr> 4427<tr><td align="left"> ArchC </td> <td align="right"> 1296</td> <td align="right"> 1728</td> </tr> 4428<tr><td align="left"> ArchB </td> <td align="right"> 864</td> <td align="right"> 1296</td> </tr> 4429<tr><td align="left"> ArchA </td> <td align="right"> 648</td> <td align="right"> 864</td> </tr> 4430<tr><td align="left"> A0 </td> <td align="right"> 2380</td> <td align="right"> 3368</td> </tr> 4431<tr><td align="left"> A1 </td> <td align="right"> 1684</td> <td align="right"> 2380</td> </tr> 4432<tr><td align="left"> A2 </td> <td align="right"> 1190</td> <td align="right"> 1684</td> </tr> 4433<tr><td align="left"> A3 </td> <td align="right"> 842</td> <td align="right"> 1190</td> </tr> 4434<tr><td align="left"> A4 </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr> 4435<tr><td align="left"> A4Small </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr> 4436<tr><td align="left"> A5 </td> <td align="right"> 421</td> <td align="right"> 595</td> </tr> 4437<tr><td align="left"> A6 </td> <td align="right"> 297</td> <td align="right"> 421</td> </tr> 4438<tr><td align="left"> A7 </td> <td align="right"> 210</td> <td align="right"> 297</td> </tr> 4439<tr><td align="left"> A8 </td> <td align="right"> 148</td> <td align="right"> 210</td> </tr> 4440<tr><td align="left"> A9 </td> <td align="right"> 105</td> <td align="right"> 148</td> </tr> 4441<tr><td align="left"> A10 </td> <td align="right"> 74</td> <td align="right"> 105</td> </tr> 4442<tr><td align="left"> B0 </td> <td align="right"> 2836</td> <td align="right"> 4008</td> </tr> 4443<tr><td align="left"> B1 </td> <td align="right"> 2004</td> <td align="right"> 2836</td> </tr> 4444<tr><td align="left"> B2 </td> <td align="right"> 1418</td> <td align="right"> 2004</td> </tr> 4445<tr><td align="left"> B3 </td> <td align="right"> 1002</td> <td align="right"> 1418</td> </tr> 4446<tr><td align="left"> B4 </td> <td align="right"> 709</td> <td align="right"> 1002</td> </tr> 4447<tr><td align="left"> B5 </td> <td align="right"> 501</td> <td align="right"> 709</td> </tr> 4448<tr><td align="left"> C0 </td> <td align="right"> 2600</td> <td align="right"> 3677</td> </tr> 4449<tr><td align="left"> C1 </td> <td align="right"> 1837</td> <td align="right"> 2600</td> </tr> 4450<tr><td align="left"> C2 </td> <td align="right"> 1298</td> <td align="right"> 1837</td> </tr> 4451<tr><td align="left"> C3 </td> <td align="right"> 918</td> <td align="right"> 1298</td> </tr> 4452<tr><td align="left"> C4 </td> <td align="right"> 649</td> <td align="right"> 918</td> </tr> 4453<tr><td align="left"> C5 </td> <td align="right"> 459</td> <td align="right"> 649</td> </tr> 4454<tr><td align="left"> C6 </td> <td align="right"> 323</td> <td align="right"> 459</td> </tr> 4455<tr><td align="left"> Flsa </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr> 4456<tr><td align="left"> Flse </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr> 4457<tr><td align="left"> HalfLetter </td> <td align="right"> 396</td> <td align="right"> 612</td> </tr> 4458</tbody> 4459</table> 4460 4461 4462 4463 4464<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> 4465 4466<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> 4467 4468<p>The default page dimensions for a TEXT image is 612x792.</p> 4469 4470<p>This option is used in concert with <a href="#density">-density</a>.</p> 4471 4472<p>Use <a href="#page">+page</a> to remove the page settings for an image.</p> 4473 4474<div style="margin: auto;"> 4475 <h4><a name="paint" id="paint"></a>-paint <em class="arg">radius</em></h4> 4476</div> 4477 4478<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> 4479 4480<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> 4481 4482<div style="margin: auto;"> 4483 <h4><a name="path" id="path"></a>-path <em class="arg">path</em></h4></div> 4484 4485<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> 4486 4487<div style="margin: auto;"> 4488 <h4><a name="pause_animate_" id="pause_animate_"></a>-pause <em class="arg">seconds</em></h4> 4489</div> 4490 4491<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> 4492 4493<p>Pause for the specified number of seconds before repeating the animation.</p> 4494 4495<div style="margin: auto;"> 4496 <h4><a name="pause_import_" id="pause_import_"></a>-pause <em class="arg">seconds</em></h4> 4497</div> 4498 4499<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> 4500 4501<p>Pause for the specified number of seconds before taking the next snapshot.</p> 4502 4503<div style="margin: auto;"> 4504 <h4><a name="ping" id="ping"></a>-ping</h4> 4505</div> 4506 4507<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> 4508 4509<div style="margin: auto;"> 4510 <h4><a name="pointsize" id="pointsize"></a>-pointsize <em class="arg">value</em></h4> 4511</div> 4512 4513<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> 4514 4515<div style="margin: auto;"> 4516 <h4><a name="polaroid" id="polaroid"></a>-polaroid <em class="arg">angle</em></h4> 4517</div> 4518 4519<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> 4520 4521<p>Use <kbd>+polaroid</kbd> to rotate the image at a random angle between -15 and +15 degrees.</p> 4522 4523<div style="margin: auto;"> 4524 <h4><a name="posterize" id="posterize"></a>-posterize <em class="arg">levels</em></h4> 4525</div> 4526 4527<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> 4528 4529<div style="margin: auto;"> 4530 <h4><a name="precision" id="precision"></a>-precision <em class="arg">value</em></h4> 4531</div> 4532 4533<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> 4534 4535<div style="margin: auto;"> 4536 <h4><a name="preview" id="preview"></a>-preview <em class="arg">type</em></h4> 4537</div> 4538 4539<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> 4540 4541<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> 4542 4543<pre class="text"> 4544 Rotate 4545 Shear 4546 Roll 4547 Hue 4548 Saturation 4549 Brightness 4550 Gamma 4551 Spiff 4552 Dull 4553 Grayscale 4554 Quantize 4555 Despeckle 4556 ReduceNoise 4557 Add Noise 4558 Sharpen 4559 Blur 4560 Threshold 4561 EdgeDetect 4562 Spread 4563 Shade 4564 Raise 4565 Segment 4566 Solarize 4567 Swirl 4568 Implode 4569 Wave 4570 OilPaint 4571 CharcoalDrawing 4572 JPEG 4573</pre> 4574 4575<p>To print a complete list of previews, use the <a href="#list">-list preview</a> option.</p> 4576 4577<p>The default preview is <kbd>JPEG</kbd>.</p> 4578 4579<div style="margin: auto;"> 4580 <h4><a name="print" id="print"></a>-print <em class="arg">string</em></h4> 4581</div> 4582 4583<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> 4584 4585<div style="margin: auto;"> 4586 <h4><a name="process" id="process"></a>-process <em class="arg">command</em></h4> 4587</div> 4588 4589<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> 4590 4591<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> 4592 4593<div style="margin: auto;"> 4594 <h4><a name="profile" id="profile"></a>-profile <em class="arg">filename</em><br/> 4595 +profile <em class="arg">profile_name</em></h4> 4596</div> 4597 4598<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> 4599 4600<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> 4601 4602<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> 4603 4604<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> 4605 4606<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> 4607 4608<p>For example, to extract the Exif data (which is stored in JPEG files in the <em class="arg">APP1</em> profile), use.</p> 4609 4610<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert cockatoo.jpg profile.exif</span></p> 4611<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> 4612 4613<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert CMYK.tif -profile "CMYK.icc" -profile "RGB.icc" RGB.tiff</span></p> 4614<p>Furthermore, since ICC profiles are not necessarily symmetric, extra conversion steps can yield unwanted results. 4615CMYK profiles are often very asymmetric since they involve 3−>4 and 4−>3 channel mapping. 4616</p> 4617 4618<div style="margin: auto;"> 4619 <h4><a name="quality" id="quality"></a>-quality <em class="arg">value</em></h4> 4620</div> 4621 4622<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> 4623 4624<p>For the JPEG and MPEG image formats, quality is 1 (lowest image quality and highest compression) to 100 (best quality but least effective compression). The default is to use the estimate quality of your input image otherwise 92. Use the <a href="#sampling-factor">-sampling-factor</a> option to specify the factors for chroma downsampling.</p> 4625 4626<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> 4627 4628<p>For the JPEG-2000 image format, quality is mapped using a non-linear equation to the compression ratio required by the Jasper library. This non-linear equation is intended to loosely approximate the quality provided by the JPEG v1 format. The default quality value 100, a request for non-lossy compression. A quality of 75 results in a request for 16:1 compression.</p> 4629 4630<p>For the MNG and PNG image formats, the quality value sets the zlib compression level (quality / 10) and filter-type (quality % 10). For compression level 0, the Huffman-only strategy is used, which is fastest but not necessarily the worst compression. The default PNG compression is 75.</p> 4631 4632<p>If filter-type is 4 or less, the specified filter-type is used for all scanlines:</p> 4633 4634<pre class="text"> 4635 0: none 4636 1: sub 4637 2: up 4638 3: average 4639 4: Paeth 4640</pre> 4641 4642<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> 4643 4644<p>If filter-type is 6, adaptive filtering with <em class="arg">minimum-sum-of-absolute-values</em> is used.</p> 4645 4646<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> 4647 4648<p>The quality setting has no effect on the appearance of PNG and MNG images, since the compression is always lossless.</p> 4649 4650<p>For further information, see the <a href="http://www.w3.org/pub/WWW/TR">PNG</a> specification.</p> 4651 4652<div style="margin: auto;"> 4653 <h4><a name="quantize" id="quantize"></a>-quantize <em class="arg">colorspace</em></h4> 4654</div> 4655 4656<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>reduce colors using this colorspace.</td><td style='text-align:right;'></td></tr></table> 4657 4658<p>This setting defines the colorspace used to sort out and reduce the number 4659of colors needed by an image (for later dithering) by operators such as <a 4660href="#colors" >-colors</a>, Note that color reducion also happens 4661automatically when saving images to color-limited image file formats, such as 4662GIF, and PNG8.</p> 4663 4664 4665<div style="margin: auto;"> 4666 <h4><a name="quiet" id="quiet"></a>-quiet</h4> 4667</div> 4668 4669<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> 4670 4671<div style="margin: auto;"> 4672 <h4><a name="radial-blur" id="radial-blur"></a>-radial-blur <em class="arg">angle</em></h4> 4673</div> 4674 4675<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> 4676 4677<p>Note that this is actually a rotational blur rather than a radial and as 4678such actually mis-named. </p> 4679 4680<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 4681pixels which are outside the image proper are blurred into the final result. 4682</p> 4683 4684 4685<div style="margin: auto;"> 4686 <h4><a name="raise" id="raise"></a>-raise <em class="arg">thickness</em></h4> 4687</div> 4688 4689<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> 4690 4691<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>. 4692</p> 4693 4694<p>Unlike the similar <a href="#frame">-frame</a> option, <a href="#raise">-raise</a> does not alter the dimensions of the image.</p> 4695 4696<div style="margin: auto;"> 4697 <h4><a name="random-threshold" id="random-threshold"></a>-random-threshold <em class="arg">low</em>x<em class="arg">high</em></h4> 4698</div> 4699 4700<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> 4701 4702<div style="margin: auto;"> 4703 <h4><a name="red-primary" id="red-primary"></a>-red-primary <em class="arg">x,y</em></h4> 4704</div> 4705 4706<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> 4707 4708<div style="margin: auto;"> 4709 <h4><a name="regard-warnings" id="regard-warnings"></a>-regard-warnings</h4> 4710</div> 4711 4712<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> 4713 4714<div style="margin: auto;"> 4715 <h4><a name="remap" id="remap"></a>-remap <em class="arg">filename</em></h4> 4716</div> 4717 4718<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> 4719 4720<p>If the <a href="#dither">-dither</a> setting is enabled (the default) then 4721the given colors are dithered over the image as necessary, otherwise the closest 4722color (in RGB colorspace) is selected to replace that pixel in the image. </p> 4723 4724<p>As a side effect of applying a <a href="#remap">-remap</a> of colors across all 4725images in the current image sequence, all the images will have the same color 4726table. That means that when saved to a file format such as GIF, it will use 4727that color table as a single common or global color table, for all the images, 4728without requiring extra local color tables. </p> 4729 4730<p>Use <a href="#remap">+remap</a> to reduce all images in the current image 4731sequence to use a common color map over all the images. This equivalent to 4732appending all the images together (without extra background colors) and color 4733reducing those images using <a href="#colors">-colors</a> with a 256 color 4734limit, then <a href="#remap">-remap</a> those colors over the original list of 4735images. This ensures all the images follow a single color map. </p> 4736 4737<p>If the number of colors over all the images is less than 256, then <a 4738href="#remap">+remap</a> should not perform any color reduction or dithering, as 4739no color changes are needed. In that case, its only effect is to force the use 4740of a global color table. This recommended after using either <a 4741href="#colors">-colors</a> or <a href="#ordered-dither">-ordered-dither</a> to 4742reduce the number of colors in an animated image sequence. </p> 4743 4744<div style="margin: auto;"> 4745 <h4><a name="region" id="region"></a>-region <em class="arg">geometry</em></h4> 4746</div> 4747 4748<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> 4749 4750<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> 4751 4752<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> 4753 4754<div style="margin: auto;"> 4755 <h4><a name="remote" id="remote"></a>-remote</h4> 4756</div> 4757 4758<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> 4759 4760<p>The only command recognized is the name of an image file to load.</p> 4761 4762<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> 4763 4764<div style="margin: auto;"> 4765 <h4><a name="render" id="render"></a>-render</h4> 4766</div> 4767 4768<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> 4769 4770<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> 4771 4772<div style="margin: auto;"> 4773<h4><a name="repage" id="repage"></a>-repage <em class="arg">geometry</em></h4> 4774</div> 4775 4776<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> 4777 4778<p>This option is like <a href="#page">-page</a> but acts as an image operator 4779rather than a setting. You can separately set the canvas size or the offset 4780of the image on that canvas by only providing those components. </p> 4781 4782<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> 4783 4784<p>If a <kbd>!</kbd> flag is given the offset given is added to the existing 4785offset to move the image relative to its previous position. This useful for 4786animation sequences. </p> 4787 4788<p>A given a canvas size of zero such as '<kbd>0x0</kbd>' forces it to 4789recalculate the canvas size so the image (at its current offset) will appear 4790completely on that canvas (unless it has a negative offset).</p> 4791 4792<p>Use <a href="#repage">+repage</a> to completely remove/reset the virtual 4793canvas meta-data from the images. </p> 4794 4795<p>The <a href="#set">-set</a> '<kbd>page</kbd>' option can be used to 4796directly assign virtual canvas meta-data. </p> 4797 4798 4799<div style="margin: auto;"> 4800 <h4><a name="resample" id="resample"></a>-resample <em class="arg">horizontal</em>x<em class="arg">vertical</em></h4> 4801</div> 4802 4803<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> 4804 4805<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> 4806 4807<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> 4808 4809<div style="margin: auto;"> 4810 <h4><a name="resize" id="resize"></a>-resize <em class="arg">geometry</em></h4> 4811</div> 4812 4813<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> 4814 4815<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> 4816 4817<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> 4818 4819<p>Many image processing algorithms assume your image is in a linear-light coding. If your image is gamma-corrected, you can remove the nonlinear gamma correction, apply the transform, then restore it like this:</p> 4820 4821<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert portrait.jpg -gamma .45455 -resize 25% -gamma 2.2 \ <br/> -quality 92 passport.jpg</span></p> 4822<div style="margin: auto;"> 4823 <h4><a name="respect-parentheses" id="respect-parentheses"></a>-respect-parentheses</h4> 4824</div> 4825 4826<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> 4827 4828<div style="margin: auto;"> 4829 <h4><a name="reverse" id="reverse"></a>-reverse</h4> 4830</div> 4831 4832<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> 4833 4834 4835<div style="margin: auto;"> 4836 <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> 4837</div> 4838 4839<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> 4840 4841<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> 4842 4843 4844<div style="margin: auto;"> 4845 <h4><a name="rotate" id="rotate"></a>-rotate <em class="arg">degrees</em>{<em class="arg"><</em>}{<em class="arg">></em>}</h4> 4846</div> 4847 4848<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> 4849 4850<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> 4851 4852<p>Empty triangles in the corners, left over from rotating the image, are 4853filled with the <kbd>background</kbd> color. </p> 4854 4855<p>See also the <a href="#distort">-distort</a> operator and specifically the 4856'<kbd>ScaleRotateTranslate</kbd>' distort method. </p> 4857 4858 4859<div style="margin: auto;"> 4860 <h4><a name="sample" id="sample"></a>-sample <em class="arg">geometry</em></h4> 4861</div> 4862 4863<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>minify/magnify the image using pixel subsampling and pixel replication, respectively.</td><td style='text-align:right;'></td></tr></table> 4864 4865<p>Change the image size simply by directly sampling the pixels original 4866image. When magnifying, pixels are replicated in blocks. When minifying, 4867pixels are sub-sampled (i.e., some rows and columns are skipped over). </p> 4868 4869<p>The results are thus equivalent to using <a href="#resize">-resize</a> with 4870a <a href="#filter">-filter</a> setting of <kbd>point</kbd> (nearest 4871neighbour), though <a href="#sample">-sample</a> is a lot faster, as it 4872avoids all the filter processing of the image. As such it completely ignores 4873the current <a href="#filter">-filter</a> setting. </p> 4874 4875<p>The key feature of the <a href="#sample">-sample</a> is that no new colors 4876will be added to the resulting image, though some colors may disappear. </p> 4877 4878<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 4879ignored, unlike <a href="#resize">-resize</a>. </p> 4880 4881 4882<div style="margin: auto;"> 4883 <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> 4884</div> 4885 4886<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> 4887 4888<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> 4889 4890<div style="margin: auto;"> 4891 <h4><a name="scale" id="scale"></a>-scale <em class="arg">geometry</em></h4> 4892</div> 4893 4894<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>minify/magnify the image using pixel block averaging and pixel replication, respectively.</td><td style='text-align:right;'></td></tr></table> 4895 4896<p>Change the image size simply by replacing pixels by averaging pixels 4897together when minifying, or replacing pixels when magnifing. </p> 4898 4899<p>The results are thus equivalent to using <a href="#resize">-resize</a> with 4900a <a href="#filter">-filter</a> setting of <kbd>box</kbd>. Though it is a lot 4901faster, as it avoids all the filter processing of the image. As such it 4902completely ignores the current <a href="#filter">-filter</a> setting. </p> 4903 4904<p>If when shrinking (minifying) images the original image is some integer 4905multiple of the new image size, the number of pixels avergaed together to 4906produce the new pixel color is the same across the whole image. This is 4907a special case known as 'binning' and is often used as a method of reducing 4908noise in image such as those generated by digital cameras, especially in low 4909light conditions. </p> 4910 4911 4912<div style="margin: auto;"> 4913 <h4><a name="scene" id="scene"></a>-scene <em class="arg">value</em></h4> 4914</div> 4915 4916<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> 4917 4918<p>This option sets the scene number of an image or the first image in an image sequence.</p> 4919 4920<div style="margin: auto;"> 4921 <h4><a name="screen" id="screen"></a>-screen</h4> 4922</div> 4923 4924<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> 4925 4926<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> 4927 4928<div style="margin: auto;"> 4929 <h4><a name="seed" id="seed"></a>-seed</h4> 4930</div> 4931 4932<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> 4933 4934<div style="margin: auto;"> 4935 <h4><a name="segment" id="segment"></a>-segment <em class="arg">cluster-threshold</em>x<em class="arg">smoothing-threshold</em></h4> 4936</div> 4937 4938<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> 4939 4940<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> 4941 4942<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> 4943 4944<p>If the <a href="#verbose">-verbose</a> setting is defined, a detailed report 4945of the color clusters is returned.</p> 4946 4947 4948<div style="margin: auto;"> 4949 <h4><a name="selective-blur" id="selective-blur"></a>-selective-blur <em class="arg">geometry</em></h4> 4950</div> 4951 4952<div style="margin: auto;"> 4953 <h4><a name="selective-blur" id="selective-blur"></a>-selective-blur <em class="arg">radius</em><br />-unsharp <em class="arg">radius</em>x<em class="arg">sigma</em>{<em class="arg">+threshold</em>}</h4> 4954</div> 4955 4956<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> 4957 4958<p>Blurs those pixels that are less than or equal to the threshold in contrast. The threshold may be expressed as a fraction of <em class="QR">QuantumRange</em> or as a percentage.</p> 4959 4960<div style="margin: auto;"> 4961 <h4><a name="separate" id="separate"></a>-separate</h4> 4962</div> 4963 4964<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> 4965 4966<div style="margin: auto;"> 4967 <h4><a name="sepia-tone" id="sepia-tone"></a>-sepia-tone <em class="arg">threshold</em></h4> 4968</div> 4969 4970<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> 4971 4972<p>Specify <em class="arg">threshold</em> as the percent threshold of the intensity (0 - 99.9%).</p> 4973 4974<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> 4975 4976 4977 4978<div style="margin: auto;"> 4979 <h4><a name="set" id="set"></a>-set <em class="arg">key value</em></h4> 4980 <h4><a name="set" id="set"></a>+set <em class="arg">key</em></h4> 4981</div> 4982 4983<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>sets image attributes and properties for images in the current 4984image sequence.</td><td style='text-align:right;'></td></tr></table> 4985 4986<p>This will assign (or modify) specific settings attached to all the images 4987in the current image sequence. Using the <a href="#set">+set</a> form of the 4988option will either remove, or reset that setting to a default state, as 4989appropriate. </p> 4990 4991<p>For example, it will modify specific well known image meta-data 4992'attributes' such as those normally overridden by: the options <a 4993href="#delay" >-delay</a>, <a href="#dispose" >-dispose</a>, and <a 4994href="#page" >-page</a>, <a href="#colorspace" >-colorspace</a>; generally 4995assigned before the image is read in, by using a <em class="arg">key</em> of 4996the same name. </p> 4997 4998<p>If the given <em class="arg">key</em> does not match a specific known 4999'attribute ', such as shown above, the setting is stored as a a free form 5000'properity' string. Such settings are listed in <a href="#verbose" 5001>-verbose</a> information ("<kbd>info:</kbd>" output format) as "Properties". 5002</p> 5003 5004<p>This includes string 'properities' that are set by and assigned to images 5005using the options <a href="#comment" >-comment</a>, <a href="#label" 5006>-label</a>, <a href="#caption" >-caption</a>. These options actually assign 5007a global 'artifact' which are automatically assigned (and any <a href="/www/escape.html" >Format Percent 5008Escapes</a> expanded) to images as they are read in. For example:</p> 5009 5010<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -set comment 'Rose is a rose is a rose is a rose' rose.png</span><span class='crtout'>identify -format %c rose.png</span><span class="crtprompt"> $magick> </span><span class='crtin'>Rose is a rose is a rose is a rose</span></p> 5011<p>The set value can also make use of <a href="/www/escape.html" >Format and Print Image 5012Properties</a> in the defined value. For example:</p> 5013 5014<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -set origsize '%wx%h' -resize 50% \</span><span class='crtout'> -format 'Old size = %[origsize] New size = %wx%h' info:</span><span class="crtprompt"> $magick> </span><span class='crtin'>Old size = 70x46 New size = 35x23</span></p> 5015<p>Other well known 'properities' that can be include: 5016'<kbd>date:create</kbd>' and '<kbd>date:modify</kbd>' and 5017'<kbd>signature</kbd>'. </p> 5018 5019<p>The <a href="#repage">-repage</a> operator will also allow you to modify 5020the '<kbd>page</kbd>' attribute of an image for images already in memory (also 5021see <a href="#repage">-page</a>). However it is designed to provide a finer 5022control of the sub-parts of this 'attribute'. The <a href="#set">-set page</a> 5023option will only provide a direct, unmodified assignment of '<kbd>page</kbd>' 5024attribute. </p> 5025 5026<p>This option can also associate a colorspace or profile with your image. 5027For example,</p> 5028 5029<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.psd -set profile ISOcoated_v2_eci.icc image-icc.psd</span></p> 5030<p>Some 'properties' must be defined in a specific way to be used. For 5031example only 'properties' prefixed with "<kbd>filename:</kbd>" can be used to 5032modify the output filename of an image. For example</p> 5033 5034<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -set filename:mysize '%wx%h' 'rose_%[filename:mysize].png'</span></p> 5035<p>If the setting value is prefixed with "<kbd>option:</kbd>" the setting will 5036be saved as a global "Artifact" exactly as if it was set using the <a 5037href="#define" >-define</a> option. As such settings are globel in scope, they 5038can be used to pass 'attributes' and 'properities' of one specific image, 5039in a way that allows you to use them in a completely different image, even if 5040the original image has long since been modified or destroyed. For example: </p> 5041 5042<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -set option:rosesize '%wx%h' -delete 0 \</span><span class='crtout'> label:'%[rosesize]' label_size_of_rose.gif</span></p> 5043<p>Note that <a href="/www/escape.html" >Format Percent Escapes</a> will only match 5044a 'artifact' if the given <em class="arg">key</em> does not match an existing 5045'attribute' or 'properity'. </p> 5046 5047<p>You can set the attributes of the image registry by prefixing the value 5048with <kbd>registry:</kbd>.</p> 5049 5050 5051 5052<div style="margin: auto;"> 5053 <h4><a name="shade" id="shade"></a>-shade <em class="arg">azimuth</em>x<em class="arg">elevation</em></h4> 5054</div> 5055 5056<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> 5057 5058<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> 5059 5060<div style="margin: auto;"> 5061 <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> 5062</div> 5063 5064<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> 5065 5066<div style="margin: auto;"> 5067 <h4><a name="shared-memory" 5068id="shared-memory"></a>-shared-memory</h4> 5069</div> 5070 5071<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> 5072 5073<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> 5074 5075<div style="margin: auto;"> 5076 <h4><a name="sharpen" id="sharpen"></a>-sharpen <em class="arg">radius</em>{x<em class="arg">sigma</em>}</h4> 5077</div> 5078 5079<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> 5080 5081<p>Use a Gaussian operator of the given radius and standard deviation (sigma).</p> 5082 5083<div style="margin: auto;"> 5084 <h4><a name="shave" id="shave"></a>-shave <em class="arg">geometry</em></h4> 5085</div> 5086 5087<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> 5088 5089<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> 5090 5091<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> 5092 5093<div style="margin: auto;"> 5094 <h4><a name="shear" id="shear"></a>-shear <em class="arg">Xdegrees</em>[x<em class="arg">Ydegrees</em>]</h4> 5095</div> 5096 5097<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> 5098 5099<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> 5100 5101<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> 5102 5103<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> 5104 5105<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> 5106 5107<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> 5108<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> 5109 5110<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert logo: -shear 20x60 logo-sheared.png</span></p> 5111<div style="margin: auto;"> 5112 <h4><a name="sigmoidal" id="sigmoidal-contrast"></a>-sigmoidal-contrast <em class="arg">contrast</em>x<em class="arg">mid-point</em></h4> 5113</div> 5114 5115<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> 5116 5117<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> 5118 5119<div style="margin: auto;"> 5120 <h4><a name="silent" id="silent"></a>-silent</h4> 5121</div> 5122 5123<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> 5124 5125<div style="margin: auto;"> 5126 <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> 5127</div> 5128 5129<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> 5130 5131<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> 5132 5133<p>For Photo CD images, choose from these sizes:</p> 5134 5135<pre class="text"> 5136 192x128 5137 384x256 5138 768x512 5139 1536x1024 5140 3072x2048 5141</pre> 5142 5143<div style="margin: auto;"> 5144 <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> 5145</div> 5146 5147<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> 5148 5149<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> 5150 5151<div style="margin: auto;"> 5152 <h4><a name="snaps" id="snaps"></a>-snaps <em class="arg">value</em></h4> 5153</div> 5154 5155<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> 5156 5157<p>Use this option to grab more than one image from the X server screen, to create an animation sequence.</p> 5158 5159<div style="margin: auto;"> 5160 <h4><a name="solarize" id="solarize"></a>-solarize <em class="arg">threshold</em></h4> 5161</div> 5162 5163<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> 5164 5165<p>Specify <em class="arg">factor</em> as the percent threshold of the intensity (0 - 99.9%).</p> 5166 5167<p>This option produces a <em class="arg">solarization</em> effect seen when exposing a photographic film to light during the development process.</p> 5168 5169<div style="margin: auto;"> 5170 <h4><a name="sparse-color" id="sparse-color"></a>-sparse-color <em 5171 class="arg">method</em> '<em class="arg">x</em>,<em class="arg">y</em> <em class="arg">color</em> ...'</h4> 5172</div> 5173 5174<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> 5175 5176 5177<table class="doc"> 5178 <tbody> 5179 <tr valign="top"> 5180 <th align="left" style="width: 8%">Method</th> 5181 <th align="left">Description</th> 5182 </tr> 5183 5184 <tr valign="top"> 5185 <td valign="top">voronoi</td> 5186 <td valign="top">Simply map each pixel to the to nearest color point 5187 given. The result are polygonal 'cells' of solid color. </td> 5188 </tr> 5189 5190 <tr valign="top"> 5191 <td valign="top">shepards</td> 5192 <td valign="top">Colors points biased on the ratio of inverse distance 5193 squared. Generating spots of color in a sea of the average of 5194 colors. </td> 5195 </tr> 5196 5197 <tr valign="top"> 5198 <td valign="top">barycentric</td> 5199 <td valign="top">three point triangle of color given 3 points. 5200 Giving only 2 points will form a linear gradient between those points. 5201 Gradient is however not restricted to just the triangle or line. </td> 5202 </tr> 5203 5204 <tr valign="top"> 5205 <td valign="top">bilinear</td> 5206 <td valign="top">Like barycentric but for 4 points. Less than 4 points 5207 fall back to barycentric. </td> 5208 </tr> 5209 5210 </tbody> 5211</table> 5212 5213<p>The points are placed according to the images location on the virtual 5214canvas (<a href="#page" >-page</a> or <a href="#repage" >-repage</a> 5215offset), and do not actually have to exist on the given image, but may be 5216some point beyond the edge of the image. All points are floating point values. 5217</p> 5218 5219<p>Only the color channels defined by the <a href="#channel" >-channel</a> are 5220modified, whcih means the matte/alpha transparency channel is not effected by 5221default. If enabled, the image also needs a the matte/alpha channel to be 5222enabled for this operator to effect an images transparency. This is typical 5223transparency handling for images. </p> 5224 5225<p>All the above methods when given a single point of color will replace all 5226the colors in the image with the color given, regardless of the point. This is 5227logical, and provides an alternative technique to recolor a image to some 5228default value. </p> 5229 5230 5231<div style="margin: auto;"> 5232 <h4><a name="splice" id="splice"></a>-splice <em class="arg">geometry</em></h4> 5233</div> 5234 5235<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> 5236 5237<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> 5238 5239<div style="margin: auto;"> 5240 <h4><a name="spread" id="spread"></a>-spread <em class="arg">amount</em></h4> 5241</div> 5242 5243<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> 5244 5245<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> 5246 5247<div style="margin: auto;"> 5248 <h4><a name="stegano" id="stegano"></a>-stegano <em class="arg">offset</em></h4> 5249</div> 5250 5251<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> 5252 5253<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> 5254 5255<div style="margin: auto;"> 5256 <h4><a name="stereo" id="stereo"></a>-stereo <em class="arg">+x</em>{<em class="arg">+y</em>}</h4> 5257</div> 5258 5259<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> 5260 5261<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> 5262 5263<div style="margin: auto;"> 5264 <h4><a name="storage-type" id="storage-type"></a>-storage-type <em class="arg">type</em></h4> 5265</div> 5266 5267<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> 5268 5269<pre class="text"> 5270 char store pixels as unsigned characters 5271 double store pixels as doubles 5272 float store pixels as floats 5273 integer store pixels as integers 5274 long store pixels as longs 5275 quantum store pixels in the native depth of your ImageMagick distribution 5276 short store pixels as unsigned shorts 5277</pre> 5278 5279<p>Float and double types are normalized from 0.0 to 1.0 otherwise the pixels 5280values range from 0 to the maximum value the storage type can support.</p> 5281 5282<div style="margin: auto;"> 5283 <h4><a name="stretch" id="stretch"></a>-stretch <em class="arg">fontStretch</em></h4> 5284</div> 5285 5286<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> 5287 5288<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> 5289 5290<pre class="text"> 5291 Any 5292 Condensed 5293 Expanded 5294 ExtraCondensed 5295 ExtraExpanded 5296 Normal 5297 SemiCondensed 5298 SemiExpanded 5299 UltraCondensed 5300 UltraExpanded 5301</pre> 5302 5303<p>To print a complete list of stretch types, use <a href="#list">-list stretch</a>.</p> 5304 5305<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> 5306 5307<div style="margin: auto;"> 5308 <h4><a name="strip" id="strip"></a>-strip</h4> 5309</div> 5310 5311<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> 5312 5313<div style="margin: auto;"> 5314 <h4><a name="stroke" id="stroke"></a>-stroke <em class="arg">color</em></h4> 5315</div> 5316 5317<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> 5318 5319<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 5320 5321<p>See <a href="#draw">-draw</a> for further details.</p> 5322 5323<div style="margin: auto;"> 5324 <h4><a name="strokewidth" id="strokewidth"></a>-strokewidth <em class="arg">value</em></h4> 5325</div> 5326 5327<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> 5328 5329<p>See <a href="#draw">-draw</a> for further details.</p> 5330 5331<div style="margin: auto;"> 5332 <h4><a name="style" id="style"></a>-style <em class="arg">fontStyle</em></h4> 5333</div> 5334 5335<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> 5336 5337<p>This setting suggests a font style that ImageMagick should try to apply to 5338the currently selected font family. Select <em class="arg">fontStyle</em> from 5339the following.</p> 5340 5341<pre class="text"> 5342 Any 5343 Italic 5344 Normal 5345 Oblique 5346</pre> 5347 5348<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> 5349 5350<div style="margin: auto;"> 5351 <h4><a name="subimage-search" id="subimage-search"></a>-subimage-search</h4> 5352</div> 5353 5354<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>search for subimage.</td><td style='text-align:right;'>[<a href="/www/compare.html">compare</a>]</td></tr></table> 5355 5356<p>This option is required to have compare search for the best match location 5357of a small image within a larger image. This search will produce two images 5358(or two frames). The first is the "difference" image and the second will 5359be the "match score" image.</p> 5360 5361<p>The "match-score" image is smaller containing a pixel for ever possible 5362position of the top-left corner of the given sub-image. that is its size will 5363be the size of the larger_image - sub_image + 1. The brightest location in 5364this image is the location s the locate on the best match that is also 5365reported. Note that this may or may nor be a perfect match, and the actual 5366brightness will reflect this. Other bright 'peaks' can be used to locate other 5367possible matching loctions. </p> 5368 5369<p>Note that the search will try to compare teh sub-image at every possible 5370location in the larger image, as such it can be very slow. The smaller the 5371sub-image the faster this search is. </p> 5372 5373 5374<div style="margin: auto;"> 5375 <h4><a name="swap" id="swap"></a>-swap <em class="arg">index,index</em></h4> 5376</div> 5377 5378<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> 5379 5380<p>For example, <a href="#swap">-swap 0,2</a> swaps the first and the third 5381images in the current image sequence. Use <a href="#swap">+swap</a> to switch 5382the last two images in the sequence.</p> 5383 5384<div style="margin: auto;"> 5385 <h4><a name="swirl" id="swirl"></a>-swirl <em class="arg">degrees</em></h4> 5386</div> 5387 5388<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> 5389 5390<p><em class="arg">Degrees</em> defines the tightness of the swirl.</p> 5391 5392<div style="margin: auto;"> 5393 <h4><a name="synchronize" id="synchronize"></a>-synchronize</h4> 5394</div> 5395 5396<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>synchronize image to storage device.</td><td style='text-align:right;'></td></tr></table> 5397 5398<div style="margin: auto;"> 5399 <h4><a name="taint" id="taint"></a>-taint</h4> 5400</div> 5401 5402<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Mark the image as modified.</td><td style='text-align:right;'></td></tr></table> 5403 5404<div style="margin: auto;"> 5405 <h4><a name="text-font" id="text-font"></a>-text-font <em class="arg">name</em></h4> 5406</div> 5407 5408<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> 5409 5410<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> 5411 5412<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> 5413 5414<div style="margin: auto;"> 5415 <h4><a name="texture" id="texture"></a>-texture <em class="arg">filename</em></h4> 5416</div> 5417 5418<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> 5419 5420<div style="margin: auto;"> 5421 <h4><a name="threshold" id="threshold"></a>-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 5422</div> 5423 5424<!-- {<em class="arg">green,blue,opacity</em>} 5425<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> 5426--> 5427 5428<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> 5429 5430<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> 5431 5432<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. 5433</p> 5434 5435<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> 5436 5437<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert in.png -channel red -threshold 50% out.png</span></p> 5438<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> 5439 5440 5441<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> 5442<p>Note that the values of the transparency channel is treated as 'matte' 5443values (0 is opaque) and not as 'alpha' values (0 is transparent).</p> 5444 5445<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>. 5446</p> 5447 5448<div style="margin: auto;"> 5449 <h4><a name="thumbnail" id="thumbnail"></a>-thumbnail <em class="arg">geometry</em></h4> 5450</div> 5451 5452<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> 5453 5454<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> 5455 5456<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> 5457 5458<div style="margin: auto;"> 5459 <h4><a name="tile" id="tile"></a>-tile <em class="arg">filename</em></h4> 5460</div> 5461 5462<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> 5463 5464<div style="margin: auto;"> 5465 <h4>-tile <em class="arg">geometry</em></h4> 5466</div> 5467 5468<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> 5469 5470<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> 5471 5472<div style="margin: auto;"> 5473 <h4>-tile</h4> 5474</div> 5475 5476<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> 5477 5478<div style="margin: auto;"> 5479 <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> 5480</div> 5481 5482<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> 5483 5484<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> 5485 5486<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> 5487 5488<div style="margin: auto;"> 5489 <h4><a name="tint" id="tint"></a>-tint <em class="arg">value</em></h4> 5490</div> 5491 5492<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> 5493 5494<p>Tint the image with the fill color.</p> 5495 5496<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> 5497 5498<div style="margin: auto;"> 5499 <h4><a name="title" id="title"></a>-title <em class="arg">string</em></h4> 5500</div> 5501 5502<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> 5503 5504<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> 5505 5506<p>For example,</p> 5507 5508<p class="crtsnip"> 5509 -title "%m:%f %wx%h" 5510</p> 5511 5512<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> 5513 5514 5515<div style="margin: auto;"> 5516 <h4><a name="transform" id="transform"></a>-transform</h4> 5517</div> 5518 5519<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> 5520 5521<p>This option applies the transformation matrix from a previous <a href="#affine">-affine</a> option.</p> 5522 5523<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> 5524 5525<p>This operator has been now been superseded by the <a 5526href="#distort">-distort</a> '<kbd>AffineProjection</kbd>' method. </p> 5527 5528 5529<div style="margin: auto;"> 5530 <h4><a name="transparent" id="transparent"></a>-transparent <em class="arg">color</em></h4> 5531</div> 5532 5533<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> 5534 5535<p>The <em class="arg">color</em> argument is defined using the format 5536described under the <a href="#fill">-fill</a> option. The <a href="#fuzz" 5537>-fuzz</a> setting can be used to match and replace colors similar to the one 5538given. </p> 5539 5540<p>Use <a href="#transparent" >+transparent</a> to invert the pixels matched. 5541that is make all non-matching colors transparent. </p> 5542 5543<p>The <a href="#opaque">-opaque</a> operator is exactly the same as <a 5544href="#transparent" >-transparent</a> but replaces the matching color with the 5545current <a href="#fill">-fill</a> color setting, rather than transparent. 5546However the <a href="#transparent" >-transparent</a> operator also ensures 5547that the image has an alpha channel enabled, as per "<kbd><a href="#alpha" 5548>-alpha</a> set</kbd>", and does not require you to modify the <a 5549href="#channel">-channel</a> to enable alpha channel handling. </p> 5550 5551<p>Note that this does not define the color as being the 'transparency color' 5552used for color-mapped image formats, such as GIF. For that use <a 5553href="#transparent-color" >-transparent-color</a> </p> 5554 5555 5556<div style="margin: auto;"> 5557 <h4><a name="transparent-color" id="transparent-color"></a>-transparent-color <em class="arg">color</em></h4> 5558</div> 5559 5560<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> 5561 5562<p>Sometimes this is used for saving to image formats such as 5563GIF and PNG8 which uses this color to represent boolean transparency. This 5564does not make a color transparent, it only defines what color the transparent 5565color is in the color palette of the saved image. Use <a 5566href="#transparent">-transparent</a> to make an opaque color transparent.</p> 5567 5568<p>This option allows you to have both an opaque visible color, as well as a 5569transparent color of the same color value without conflict. That is, you can 5570use the same color for both the transparent and opaque color areas within an 5571image. This, in turn, frees to you to select a transparent color that is 5572appropriate when an image is displayed by an application that does not handle a 5573transparent color index, while allowing ImageMagick to correctly handle images of this 5574type. </p> 5575 5576<p>The default transparent color is <kbd>#00000000</kbd>, which is fully transparent black.</p> 5577 5578<div style="margin: auto;"> 5579 <h4><a name="transpose" id="transpose"></a>-transpose</h4> 5580</div> 5581 5582<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> 5583 5584<p> This option mathematically transposes the pixel array. It is equivalent to the sequence <kbd>-flip -rotate 90</kbd>. 5585</p> 5586 5587<div style="margin: auto;"> 5588 <h4><a name="transverse" id="transverse"></a>-transverse</h4> 5589</div> 5590 5591<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Mirror the image along the images bottom-left top-right diagonal. Equivalent to the operations <kbd>-flop -rotate 90</kbd>.</td><td style='text-align:right;'></td></tr></table> 5592 5593 5594<div style="margin: auto;"> 5595 <h4><a name="treedepth" id="treedepth"></a>-treedepth <em class="arg">value</em></h4> 5596</div> 5597 5598<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> 5599 5600<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> 5601 5602<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> 5603 5604<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> 5605 5606<div style="margin: auto;"> 5607 <h4><a name="trim" id="trim"></a>-trim</h4> 5608</div> 5609 5610<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> 5611 5612<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> 5613 5614<p>The page or virtual canvas information of the image is preserved allowing 5615you to extract the result of the <a href="#trim">-trim</a> operation from the 5616image. Use a <a href="#repage">+repage</a> to remove the virtual canvas page 5617information if it is unwanted.</p> 5618 5619<p>If the trimmed image 'disappears' an warning is produced, and a special 5620single pixel transparent 'missed' image is returned, in the same way as when a 5621<a href="#crop">-crop</a> operation 'misses' the image proper. </p> 5622 5623 5624<div style="margin: auto;"> 5625 <h4><a name="type" id="type"></a>-type <em class="arg">type</em></h4> 5626</div> 5627 5628<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> 5629 <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> 5630 5631<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> 5632 5633<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert bird.png -type TrueColor bird.jpg</span></p> 5634<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> 5635 5636<p>Use <a href="#type">-type optimize</a> to ensure the image is written in the smallest possible file size.</p> 5637 5638<div style="margin: auto;"> 5639 <h4><a name="undercolor" id="undercolor"></a>-undercolor <em class="arg">color</em></h4> 5640</div> 5641 5642<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> 5643 5644<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 5645 5646<p>See <a href="#draw">-draw</a> for further details.</p> 5647 5648 5649<div style="margin: auto;"> 5650 <h4><a name="update" id="update"></a>-update <em class="arg">seconds</em></h4> 5651</div> 5652 5653<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> 5654 5655<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> 5656 5657 5658<div style="margin: auto;"> 5659 <h4><a name="unique-colors" id="unique-colors"></a>-unique-colors</h4> 5660</div> 5661 5662<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> 5663 5664 5665<div style="margin: auto;"> 5666 <h4><a name="units" id="units"></a>-units <em class="arg">type</em></h4> 5667</div> 5668 5669<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> 5670 5671<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> 5672 5673 5674<div style="margin: auto;"> 5675 <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> 5676</div> 5677 5678<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> 5679 5680<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> 5681 5682<p>The parameters are:</p> 5683 5684<pre class="text"> 5685 radius: The radius of the Gaussian, in pixels, not counting the center 5686 pixel (default 0). 5687 sigma: The standard deviation of the Gaussian, in pixels (default 1.0). 5688 amount: The fraction of the difference between the original and the blur 5689 image that is added back into the original (default 1.0). 5690 threshold: The threshold, as a fraction of <em class="QR">QuantumRange</em>, needed to apply the 5691 difference amount (default 0.05). 5692</pre> 5693 5694 5695<div style="margin: auto;"> 5696 <h4><a name="verbose" id="verbose"></a>-verbose</h4> 5697</div> 5698 5699<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>print detailed information about the image when this option precedes the <a href="#identify">-identify</a> option or <kbd>info:</kbd>.</td><td style='text-align:right;'></td></tr></table> 5700 5701 5702<div style="margin: auto;"> 5703 <h4><a name="version" id="version"></a>-version</h4> 5704</div> 5705 5706<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> 5707 5708 5709<div style="margin: auto;"> 5710 <h4><a name="view" id="view"></a>-view <em class="arg">string</em></h4> 5711</div> 5712 5713<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> 5714 5715 5716<div style="margin: auto;"> 5717 <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> 5718</div> 5719 5720<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> 5721 5722 5723<div style="margin: auto;"> 5724 <h4><a name="virtual-pixel" id="virtual-pixel"></a>-virtual-pixel <em class="arg">method</em></h4> 5725</div> 5726 5727<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> 5728 5729<p>This option defines what color source should be used if and when a color 5730lookup completely 'misses' the source image. The color(s) that appear to 5731surround the source image. Generally this color is derived from the source 5732image, but could also be set to a specify background color. </p> 5733 5734<p>Choose from these methods:</p> 5735 5736<pre class="text"> 5737 background: the area surrounding the image is the background color 5738 black: the area surrounding the image is black 5739 checker-tile: alternate squares with image and background color 5740 dither: non-random 32x32 dithered pattern 5741 edge: extend the edge pixel toward infinity 5742 gray: the area surrounding the image is gray 5743 horizontal-tile: horizontally tile the image, background color above/below 5744 horizontal-tile-edge: horizontally tile the image and replicate the side edge pixels 5745 mirror: mirror tile the image 5746 random: choose a random pixel from the image 5747 tile: tile the image (default) 5748 transparent: the area surrounding the image is transparent blackness 5749 vertical-tile: vertically tile the image, sides are background color 5750 vertical-tile-edge: vertically tile the image and replicate the side edge pixels 5751 white: the area surrounding the image is white 5752</pre> 5753 5754<p>The default value is "edge".</p> 5755 5756<p>This most important for distortion operators such as <a href="#distort" 5757>-distort</a>, <a href="#implode" >-implode</a>, and <a href="#fx" >-fx</a>. 5758However it also effects operations that may access pixels just outside the 5759image proper, such as <a href="#convolve">-convolve</a>, <a 5760href="#blur">-blur</a>, and <a href="#sharpen">-sharpen</a>. </p> 5761 5762<p>To print a complete list of virtual pixel types, use the <a href="#list">-list virtual-pixel</a> option.</p> 5763 5764 5765<div style="margin: auto;"> 5766 <h4><a name="visual" id="visual"></a>-visual <em class="arg">type</em></h4> 5767</div> 5768 5769<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> 5770 5771<p>Choose from these visual classes:</p> 5772 5773<pre class="text"> 5774 StaticGray 5775 GrayScale 5776 StaticColor 5777 PseudoColor 5778 TrueColor 5779 DirectColor 5780 default 5781 visual id 5782</pre> 5783 5784<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> 5785 5786 5787<div style="margin: auto;"> 5788 <h4><a name="watermark" id="watermark"></a>-watermark <em 5789 class="arg">brightness</em>x<em class="arg">saturation</em></h4> 5790</div> 5791 5792<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 5793saturation.</td><td style='text-align:right;'>[<a href="/www/composite.html">composite</a>]</td></tr></table> 5794 5795<p>Take a grayscale image (with alpha mask) and modify the destination image's 5796brightness according to watermark image's grayscale value and the <em 5797class="arg">brightness</em> percentage. The destinations color saturation 5798attribute is just direct modified by the <em class="arg">saturation</em> 5799percentage, which defaults to 100 percent (no color change). </p> 5800 5801 5802<div style="margin: auto;"> 5803 <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> 5804</div> 5805 5806<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> 5807 5808<p>Specify <em class="arg">amplitude</em> and <em class="arg">wavelength</em> of the wave.</p> 5809 5810<div style="margin: auto;"> 5811 <h4><a name="weight" id="weight"></a>-weight <em class="arg">fontWeight</em></h4> 5812</div> 5813 5814<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> 5815 5816<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> 5817 5818<table class="doc"> 5819 <col width="25%" /> 5820 <col width="75%" /> 5821 <thead> 5822 <tr> 5823 <th><em class="arg">fontWeight</em></th> 5824 <th>Description</th> 5825 </tr> 5826 </thead> 5827 <tbody> 5828 <tr><td>All </td> <td>No effect. </td></tr> 5829 <tr><td>Bold </td> <td>Same as <em class="arg">fontWeight</em> = 700.</td></tr> 5830 <tr><td>Bolder </td> <td>Add 100 to font weight if currently ≤ 800.</td></tr> 5831 <tr><td>Lighter </td> <td>Subtract 100 to font weight if currently ≤ 100.</td></tr> 5832 <tr><td>Normal </td> <td>Same as <em class="arg">fontWeight</em> = 400.</td></tr> 5833 </tbody> 5834 </table> 5835 5836<p>To print a complete list of weight types, use <a href="#list">-list weight</a>.</p> 5837 5838<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> 5839 5840<div style="margin: auto;"> 5841 <h4><a name="white-point" id="white-point"></a>-white-point <em class="arg">x,y</em></h4> 5842</div> 5843 5844<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> 5845 5846<div style="margin: auto;"> 5847 <h4><a name="white-threshold" id="white-threshold"></a>-white-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 5848</div> 5849 5850<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> 5851 5852<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. 5853</p> 5854 5855<div style="margin: auto;"> 5856 <h4><a name="window" id="window"></a>-window <em class="arg">id</em></h4> 5857</div> 5858 5859<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> 5860 5861<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> 5862 5863<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> 5864 5865<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> 5866 5867<div style="margin: auto;"> 5868 <h4><a name="window-group" id="window-group"></a>-window-group</h4> 5869</div> 5870 5871<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> 5872 5873<div style="margin: auto;"> 5874 <h4><a name="write" id="write"></a>-write <em class="arg">filename</em></h4> 5875</div> 5876 5877<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> 5878 <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> 5879 5880<p>Use <a href="#compress">-compress</a> to specify the type of image compression.</p> 5881 5882 5883</div> 5884 5885<div id="linkbar"> 5886 <span id="linkbar-west"> </span> 5887 <span id="linkbar-center"> 5888 <a href="http://www.imagemagick.org/discourse-server/">Discourse Server</a> • 5889 <a href="http://www.imagemagick.org/MagickStudio/scripts/MagickStudio.cgi">Studio</a> 5890 </span> 5891 <span id="linkbar-east"> </span> 5892 </div> 5893 <div class="footer"> 5894 <span id="footer-west">© 1999-2010 ImageMagick Studio LLC</span> 5895 <span id="footer-east"> <a href="http://www.imagemagick.org/script/contact.php">Contact the Wizards</a></span> 5896 </div> 5897 <div style="clear: both; margin: 0; width: 100%; "></div> 5898 <script type="text/javascript"> 5899 var _gaq = _gaq || []; 5900 _gaq.push(['_setAccount', 'UA-17690367-1']); 5901 _gaq.push(['_trackPageview']); 5902 5903 (function() { 5904 var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; 5905 ga.src = ('https:' == document.location.protocol ? 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