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150
151</div>
152
153<div class="main">
154
cristy16ff93c2010-01-13 23:18:07 +0000[diff] [blame]155<p class="navigation-index">[<a href="#AutoGammaImage">AutoGammaImage</a> &bull; <a href="#AutoLevelImage">AutoLevelImage</a> &bull; <a href="#Use BrightnessContrastImage">Use BrightnessContrastImage</a> &bull; <a href="#ColorDecisionListImage">ColorDecisionListImage</a> &bull; <a href="#ClutImage">ClutImage</a> &bull; <a href="#ContrastImage">ContrastImage</a> &bull; <a href="#The ContrastStretchImage">The ContrastStretchImage</a> &bull; <a href="#EnhanceImage">EnhanceImage</a> &bull; <a href="#EqualizeImage">EqualizeImage</a> &bull; <a href="#GammaImage">GammaImage</a> &bull; <a href="#HaldClutImage">HaldClutImage</a> &bull; <a href="#LevelImage">LevelImage</a> &bull; <a href="#LevelizeImage">LevelizeImage</a> &bull; <a href="#LevelizeImageChannel">LevelizeImageChannel</a> &bull; <a href="#LevelImageColor">LevelImageColor</a> &bull; <a href="#The LinearStretchImage">The LinearStretchImage</a> &bull; <a href="#ModulateImage">ModulateImage</a> &bull; <a href="#NegateImage">NegateImage</a> &bull; <a href="#The NormalizeImage">The NormalizeImage</a> &bull; <a href="#SigmoidalContrastImage">SigmoidalContrastImage</a>]</p>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]156
157<h2><a href="http://www.imagemagick.org/api/MagickCore/enhance
158_8c.html" target="source" name="AutoGammaImage">AutoGammaImage</a></h2>
159<div class="doc-section">
160
161<p>AutoGammaImage() extract the 'mean' from the image and adjust the image to try make set its gamma appropriatally.</p></ol>
162
cristy5cadd612009-09-21 19:33:41 +0000[diff] [blame]163<p>The format of the AutoGammaImage method is:</p>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]164
165<pre class="code">
166 MagickBooleanType AutoGammaImage(Image *image)
167 MagickBooleanType AutoGammaImageChannel(Image *image,
168 const ChannelType channel)
169</pre>
170
171<p>A description of each parameter follows:</p></ol>
172
173<h5>image</h5>
174<ol><p>The image to auto-level</p></ol>
175
176<h5>channel</h5>
177<ol><p>The channels to auto-level. If the special 'SyncChannels' flag is set all given channels is adjusted in the same way using the mean average of those channels.</p></ol>
178
179 </div>
180<h2><a href="http://www.imagemagick.org/api/MagickCore/enhance
181_8c.html" target="source" name="AutoLevelImage">AutoLevelImage</a></h2>
182<div class="doc-section">
183
184<p>AutoLevelImage() adjusts the levels of a particular image channel by scaling the minimum and maximum values to the full quantum range.</p></ol>
185
186<p>The format of the LevelImage method is:</p>
187
188<pre class="code">
189 MagickBooleanType AutoLevelImage(Image *image)
190 MagickBooleanType AutoLevelImageChannel(Image *image,
191 const ChannelType channel)
192</pre>
193
194<p>A description of each parameter follows:</p></ol>
195
196<h5>image</h5>
197<ol><p>The image to auto-level</p></ol>
198
199<h5>channel</h5>
200<ol><p>The channels to auto-level. If the special 'SyncChannels' flag is set the min/max/mean value of all given channels is used for all given channels, to all channels in the same way.</p></ol>
201
202 </div>
203<h2><a href="http://www.imagemagick.org/api/MagickCore/enhance
cristy16ff93c2010-01-13 23:18:07 +0000[diff] [blame]204_8c.html" target="source" name="Use BrightnessContrastImage">Use BrightnessContrastImage</a></h2>
205<div class="doc-section">
206
207<p>Use BrightnessContrastImage() to change the brightness and/or contrast of an image. It converts the brightness and contrast parameters into slope and intercept and calls a polynomical function to apply to the image.</p></ol>
208
209<p>The format of the BrightnessContrastImage method is:</p>
210
211<pre class="code">
212 MagickBooleanType BrightnessContrastImage(Image *image,
213 const double brightness,const double contrast)
214 MagickBooleanType BrightnessContrastImageChannel(Image *image,
215 const ChannelType channel,const double brightness,
216 const double contrast)
217</pre>
218
219<p>A description of each parameter follows:</p></ol>
220
221<h5>image</h5>
222<ol><p>the image.</p></ol>
223
224<h5>channel</h5>
225<ol><p>the channel.</p></ol>
226
227<h5>brightness</h5>
228<ol><p>the brightness percent (-100 .. 100).</p></ol>
229
230<h5>contrast</h5>
231<ol><p>the contrast percent (-100 .. 100).</p></ol>
232
233 </div>
234<h2><a href="http://www.imagemagick.org/api/MagickCore/enhance
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]235_8c.html" target="source" name="ColorDecisionListImage">ColorDecisionListImage</a></h2>
236<div class="doc-section">
237
238<p>ColorDecisionListImage() accepts a lightweight Color Correction Collection (CCC) file which solely contains one or more color corrections and applies the correction to the image. Here is a sample CCC file:</p>
239
240<pre class="text">
241 <ColorCorrectionCollection xmlns="urn:ASC:CDL:v1.2">
242 <ColorCorrection id="cc03345">
243 <SOPNode>
244 <Slope> 0.9 1.2 0.5 </Slope>
245 <Offset> 0.4 -0.5 0.6 </Offset>
246 <Power> 1.0 0.8 1.5 </Power>
247 </SOPNode>
248 <SATNode>
249 <Saturation> 0.85 </Saturation>
250 </SATNode>
251 </ColorCorrection>
252 </ColorCorrectionCollection>
253</pre>
254
255<p>which includes the slop, offset, and power for each of the RGB channels as well as the saturation.</p></ol>
256
257<p>The format of the ColorDecisionListImage method is:</p>
258
259<pre class="code">
260 MagickBooleanType ColorDecisionListImage(Image *image,
261 const char *color_correction_collection)
262</pre>
263
264<p>A description of each parameter follows:</p></ol>
265
266<h5>image</h5>
267<ol><p>the image.</p></ol>
268
269<h5>color_correction_collection</h5>
270<ol><p>the color correction collection in XML.</p></ol>
271
272 </div>
273<h2><a href="http://www.imagemagick.org/api/MagickCore/enhance
274_8c.html" target="source" name="ClutImage">ClutImage</a></h2>
275<div class="doc-section">
276
cristyeaedf062010-05-29 22:36:02 +0000[diff] [blame]277<p>ClutImage() replaces each color value in the given image, by using it as an index to lookup a replacement color value in a Color Look UP Table in the form of an image. The values are extracted along a diagonal of the CLUT image so either a horizontal or vertial gradient image can be used.</p></ol>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]278
279<p>Typically this is used to either re-color a gray-scale image according to a color gradient in the CLUT image, or to perform a freeform histogram (level) adjustment according to the (typically gray-scale) gradient in the CLUT image.</p></ol>
280
281<p>When the 'channel' mask includes the matte/alpha transparency channel but one image has no such channel it is assumed that that image is a simple gray-scale image that will effect the alpha channel values, either for gray-scale coloring (with transparent or semi-transparent colors), or a histogram adjustment of existing alpha channel values. If both images have matte channels, direct and normal indexing is applied, which is rarely used.</p></ol>
282
283<p>The format of the ClutImage method is:</p>
284
285<pre class="code">
286 MagickBooleanType ClutImage(Image *image,Image *clut_image)
287 MagickBooleanType ClutImageChannel(Image *image,
288 const ChannelType channel,Image *clut_image)
289</pre>
290
291<p>A description of each parameter follows:</p></ol>
292
293<h5>image</h5>
294<ol><p>the image, which is replaced by indexed CLUT values</p></ol>
295
296<h5>clut_image</h5>
297<ol><p>the color lookup table image for replacement color values.</p></ol>
298
299<h5>channel</h5>
300<ol><p>the channel.</p></ol>
301
302 </div>
303<h2><a href="http://www.imagemagick.org/api/MagickCore/enhance
304_8c.html" target="source" name="ContrastImage">ContrastImage</a></h2>
305<div class="doc-section">
306
307<p>ContrastImage() enhances the intensity differences between the lighter and darker elements of the image. Set sharpen to a MagickTrue to increase the image contrast otherwise the contrast is reduced.</p></ol>
308
309<p>The format of the ContrastImage method is:</p>
310
311<pre class="code">
312 MagickBooleanType ContrastImage(Image *image,
313 const MagickBooleanType sharpen)
314</pre>
315
316<p>A description of each parameter follows:</p></ol>
317
318<h5>image</h5>
319<ol><p>the image.</p></ol>
320
321<h5>sharpen</h5>
322<ol><p>Increase or decrease image contrast.</p></ol>
323
324 </div>
325<h2><a href="http://www.imagemagick.org/api/MagickCore/enhance
326_8c.html" target="source" name="The ContrastStretchImage">The ContrastStretchImage</a></h2>
327<div class="doc-section">
328
329<p>The ContrastStretchImage() is a simple image enhancement technique that attempts to improve the contrast in an image by `stretching' the range of intensity values it contains to span a desired range of values. It differs from the more sophisticated histogram equalization in that it can only apply a linear scaling function to the image pixel values. As a result the `enhancement' is less harsh.</p></ol>
330
331<p>The format of the ContrastStretchImage method is:</p>
332
333<pre class="code">
334 MagickBooleanType ContrastStretchImage(Image *image,
335 const char *levels)
336 MagickBooleanType ContrastStretchImageChannel(Image *image,
cristybb503372010-05-27 20:51:26 +0000[diff] [blame]337 const size_t channel,const double black_point,
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]338 const double white_point)
339</pre>
340
341<p>A description of each parameter follows:</p></ol>
342
343<h5>image</h5>
344<ol><p>the image.</p></ol>
345
346<h5>channel</h5>
347<ol><p>the channel.</p></ol>
348
349<h5>black_point</h5>
350<ol><p>the black point.</p></ol>
351
352<h5>white_point</h5>
353<ol><p>the white point.</p></ol>
354
355<h5>levels</h5>
356<ol><p>Specify the levels where the black and white points have the range of 0 to number-of-pixels (e.g. 1, 10x90, etc.).</p></ol>
357
358 </div>
359<h2><a href="http://www.imagemagick.org/api/MagickCore/enhance
360_8c.html" target="source" name="EnhanceImage">EnhanceImage</a></h2>
361<div class="doc-section">
362
363<p>EnhanceImage() applies a digital filter that improves the quality of a noisy image.</p></ol>
364
365<p>The format of the EnhanceImage method is:</p>
366
367<pre class="code">
368 Image *EnhanceImage(const Image *image,ExceptionInfo *exception)
369</pre>
370
371<p>A description of each parameter follows:</p></ol>
372
373<h5>image</h5>
374<ol><p>the image.</p></ol>
375
376<h5>exception</h5>
377<ol><p>return any errors or warnings in this structure.</p></ol>
378
379 </div>
380<h2><a href="http://www.imagemagick.org/api/MagickCore/enhance
381_8c.html" target="source" name="EqualizeImage">EqualizeImage</a></h2>
382<div class="doc-section">
383
384<p>EqualizeImage() applies a histogram equalization to the image.</p></ol>
385
386<p>The format of the EqualizeImage method is:</p>
387
388<pre class="code">
389 MagickBooleanType EqualizeImage(Image *image)
390 MagickBooleanType EqualizeImageChannel(Image *image,
391 const ChannelType channel)
392</pre>
393
394<p>A description of each parameter follows:</p></ol>
395
396<h5>image</h5>
397<ol><p>the image.</p></ol>
398
399<h5>channel</h5>
400<ol><p>the channel.</p></ol>
401
402 </div>
403<h2><a href="http://www.imagemagick.org/api/MagickCore/enhance
404_8c.html" target="source" name="GammaImage">GammaImage</a></h2>
405<div class="doc-section">
406
407<p>GammaImage() gamma-corrects a particular image channel. The same image viewed on different devices will have perceptual differences in the way the image's intensities are represented on the screen. Specify individual gamma levels for the red, green, and blue channels, or adjust all three with the gamma parameter. Values typically range from 0.8 to 2.3.</p></ol>
408
409<p>You can also reduce the influence of a particular channel with a gamma value of 0.</p></ol>
410
411<p>The format of the GammaImage method is:</p>
412
413<pre class="code">
414 MagickBooleanType GammaImage(Image *image,const double gamma)
415 MagickBooleanType GammaImageChannel(Image *image,
416 const ChannelType channel,const double gamma)
417</pre>
418
419<p>A description of each parameter follows:</p></ol>
420
421<h5>image</h5>
422<ol><p>the image.</p></ol>
423
424<h5>channel</h5>
425<ol><p>the channel.</p></ol>
426
427<h5>gamma</h5>
428<ol><p>the image gamma.</p></ol>
429
430 </div>
431<h2><a href="http://www.imagemagick.org/api/MagickCore/enhance
432_8c.html" target="source" name="HaldClutImage">HaldClutImage</a></h2>
433<div class="doc-section">
434
435<p>HaldClutImage() applies a Hald color lookup table to the image. A Hald color lookup table is a 3-dimensional color cube mapped to 2 dimensions. Create it with the HALD coder. You can apply any color transformation to the Hald image and then use this method to apply the transform to the image.</p></ol>
436
437<p>The format of the HaldClutImage method is:</p>
438
439<pre class="code">
440 MagickBooleanType HaldClutImage(Image *image,Image *hald_image)
441 MagickBooleanType HaldClutImageChannel(Image *image,
442 const ChannelType channel,Image *hald_image)
443</pre>
444
445<p>A description of each parameter follows:</p></ol>
446
447<h5>image</h5>
448<ol><p>the image, which is replaced by indexed CLUT values</p></ol>
449
450<h5>hald_image</h5>
451<ol><p>the color lookup table image for replacement color values.</p></ol>
452
453<h5>channel</h5>
454<ol><p>the channel.</p></ol>
455
456 </div>
457<h2><a href="http://www.imagemagick.org/api/MagickCore/enhance
458_8c.html" target="source" name="LevelImage">LevelImage</a></h2>
459<div class="doc-section">
460
461<p>LevelImage() adjusts the levels of a particular image channel by scaling the colors falling between specified white and black points to the full available quantum range.</p></ol>
462
463<p>The parameters provided represent the black, and white points. The black point specifies the darkest color in the image. Colors darker than the black point are set to zero. White point specifies the lightest color in the image. Colors brighter than the white point are set to the maximum quantum value.</p></ol>
464
465<p>If a '!' flag is given, map black and white colors to the given levels rather than mapping those levels to black and white. See LevelizeImageChannel() and LevelizeImageChannel(), below.</p></ol>
466
467<p>Gamma specifies a gamma correction to apply to the image.</p></ol>
468
469<p>The format of the LevelImage method is:</p>
470
471<pre class="code">
472 MagickBooleanType LevelImage(Image *image,const char *levels)
473</pre>
474
475<p>A description of each parameter follows:</p></ol>
476
477<h5>image</h5>
478<ol><p>the image.</p></ol>
479
480<h5>levels</h5>
481<ol><p>Specify the levels where the black and white points have the range of 0-QuantumRange, and gamma has the range 0-10 (e.g. 10x90+2). A '!' flag inverts the re-mapping.</p></ol>
482
483 </div>
484<h2><a href="http://www.imagemagick.org/api/MagickCore/enhance
cristy5cadd612009-09-21 19:33:41 +0000[diff] [blame]485_8c.html" target="source" name="LevelizeImage">LevelizeImage</a></h2>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]486<div class="doc-section">
487
cristy5cadd612009-09-21 19:33:41 +0000[diff] [blame]488<p>LevelizeImage() applies the normal level operation to the image, spreading out the values between the black and white points over the entire range of values. Gamma correction is also applied after the values has been mapped.</p></ol>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]489
490<p>It is typically used to improve image contrast, or to provide a controlled linear threshold for the image. If the black and white points are set to the minimum and maximum values found in the image, the image can be normalized. or by swapping black and white values, negate the image.</p></ol>
491
cristy5cadd612009-09-21 19:33:41 +0000[diff] [blame]492<p>The format of the LevelizeImage method is:</p>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]493
494<pre class="code">
cristy5cadd612009-09-21 19:33:41 +0000[diff] [blame]495 MagickBooleanType LevelizeImage(Image *image,const double black_point,
496 const double white_point,const double gamma)
497 MagickBooleanType LevelizeImageChannel(Image *image,
498 const ChannelType channel,const double black_point,
499 const double white_point,const double gamma)
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]500</pre>
501
502<p>A description of each parameter follows:</p></ol>
503
504<h5>image</h5>
505<ol><p>the image.</p></ol>
506
507<h5>channel</h5>
508<ol><p>the channel.</p></ol>
509
510<h5>black_point</h5>
511<ol><p>The level which is to be mapped to zero (black)</p></ol>
512
513<h5>white_point</h5>
514<ol><p>The level which is to be mapped to QuantiumRange (white)</p></ol>
515
516<h5>gamma</h5>
517<ol><p>adjust gamma by this factor before mapping values. use 1.0 for purely linear stretching of image color values</p></ol>
518
519 </div>
520<h2><a href="http://www.imagemagick.org/api/MagickCore/enhance
521_8c.html" target="source" name="LevelizeImageChannel">LevelizeImageChannel</a></h2>
522<div class="doc-section">
523
524<p>LevelizeImageChannel() applies the reversed LevelImage() operation to just the specific channels specified. It compresses the full range of color values, so that they lie between the given black and white points. Gamma is applied before the values are mapped.</p></ol>
525
526<p>LevelizeImageChannel() can be called with by using a +level command line API option, or using a '!' on a -level or LevelImage() geometry string.</p></ol>
527
528<p>It can be used for example de-contrast a greyscale image to the exact levels specified. Or by using specific levels for each channel of an image you can convert a gray-scale image to any linear color gradient, according to those levels.</p></ol>
529
530<p>The format of the LevelizeImageChannel method is:</p>
531
532<pre class="code">
533 MagickBooleanType LevelizeImageChannel(Image *image,
534 const ChannelType channel,const char *levels)
535</pre>
536
537<p>A description of each parameter follows:</p></ol>
538
539<h5>image</h5>
540<ol><p>the image.</p></ol>
541
542<h5>channel</h5>
543<ol><p>the channel.</p></ol>
544
545<h5>black_point</h5>
546<ol><p>The level to map zero (black) to.</p></ol>
547
548<h5>white_point</h5>
549<ol><p>The level to map QuantiumRange (white) to.</p></ol>
550
551<h5>gamma</h5>
552<ol><p>adjust gamma by this factor before mapping values.</p></ol>
553
554 </div>
555<h2><a href="http://www.imagemagick.org/api/MagickCore/enhance
556_8c.html" target="source" name="LevelImageColor">LevelImageColor</a></h2>
557<div class="doc-section">
558
cristye7f8fdd2009-09-20 14:43:12 +0000[diff] [blame]559<p>LevelImageColor() maps the given color to "black" and "white" values, linearly spreading out the colors, and level values on a channel by channel bases, as per LevelImage(). The given colors allows you to specify different level ranges for each of the color channels seperatally.</p></ol>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]560
561<p>If the boolean 'invert' is set true the image values will modifyed in the reverse direction. That is any existing "black" and "white" colors in the image will become the color values given, with all other values compressed appropriatally. This effectivally maps a greyscale gradient into the given color gradient.</p></ol>
562
cristy5cadd612009-09-21 19:33:41 +0000[diff] [blame]563<p>The format of the LevelColorsImageChannel method is:</p>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]564
565<pre class="code">
cristy5cadd612009-09-21 19:33:41 +0000[diff] [blame]566 MagickBooleanType LevelColorsImage(Image *image,
cristye7f8fdd2009-09-20 14:43:12 +0000[diff] [blame]567 const MagickPixelPacket *black_color,
568 const MagickPixelPacket *white_color,const MagickBooleanType invert)
cristy5cadd612009-09-21 19:33:41 +0000[diff] [blame]569 MagickBooleanType LevelColorsImageChannel(Image *image,
570 const ChannelType channel,const MagickPixelPacket *black_color,
571 const MagickPixelPacket *white_color,const MagickBooleanType invert)
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]572</pre>
573
574<p>A description of each parameter follows:</p></ol>
575
576<h5>image</h5>
577<ol><p>the image.</p></ol>
578
579<h5>channel</h5>
580<ol><p>the channel.</p></ol>
581
582<h5>black_color</h5>
583<ol><p>The color to map black to/from</p></ol>
584
585<h5>white_point</h5>
586<ol><p>The color to map white to/from</p></ol>
587
588<h5>invert</h5>
589<ol><p>if true map the colors (levelize), rather than from (level)</p></ol>
590
591 </div>
592<h2><a href="http://www.imagemagick.org/api/MagickCore/enhance
593_8c.html" target="source" name="The LinearStretchImage">The LinearStretchImage</a></h2>
594<div class="doc-section">
595
596<p>The LinearStretchImage() discards any pixels below the black point and above the white point and levels the remaining pixels.</p></ol>
597
598<p>The format of the LinearStretchImage method is:</p>
599
600<pre class="code">
601 MagickBooleanType LinearStretchImage(Image *image,
602 const double black_point,const double white_point)
603</pre>
604
605<p>A description of each parameter follows:</p></ol>
606
607<h5>image</h5>
608<ol><p>the image.</p></ol>
609
610<h5>black_point</h5>
611<ol><p>the black point.</p></ol>
612
613<h5>white_point</h5>
614<ol><p>the white point.</p></ol>
615
616 </div>
617<h2><a href="http://www.imagemagick.org/api/MagickCore/enhance
618_8c.html" target="source" name="ModulateImage">ModulateImage</a></h2>
619<div class="doc-section">
620
621<p>ModulateImage() lets you control the brightness, saturation, and hue of an image. Modulate represents the brightness, saturation, and hue as one parameter (e.g. 90,150,100). If the image colorspace is HSL, the modulation is lightness, saturation, and hue. And if the colorspace is HWB, use blackness, whiteness, and hue.</p></ol>
622
623<p>The format of the ModulateImage method is:</p>
624
625<pre class="code">
626 MagickBooleanType ModulateImage(Image *image,const char *modulate)
627</pre>
628
629<p>A description of each parameter follows:</p></ol>
630
631<h5>image</h5>
632<ol><p>the image.</p></ol>
633
634<h5>modulate</h5>
635<ol><p>Define the percent change in brightness, saturation, and hue.</p></ol>
636
637 </div>
638<h2><a href="http://www.imagemagick.org/api/MagickCore/enhance
639_8c.html" target="source" name="NegateImage">NegateImage</a></h2>
640<div class="doc-section">
641
642<p>NegateImage() negates the colors in the reference image. The grayscale option means that only grayscale values within the image are negated.</p></ol>
643
644<p>The format of the NegateImageChannel method is:</p>
645
646<pre class="code">
647 MagickBooleanType NegateImage(Image *image,
648 const MagickBooleanType grayscale)
649 MagickBooleanType NegateImageChannel(Image *image,
650 const ChannelType channel,const MagickBooleanType grayscale)
651</pre>
652
653<p>A description of each parameter follows:</p></ol>
654
655<h5>image</h5>
656<ol><p>the image.</p></ol>
657
658<h5>channel</h5>
659<ol><p>the channel.</p></ol>
660
661<h5>grayscale</h5>
662<ol><p>If MagickTrue, only negate grayscale pixels within the image.</p></ol>
663
664 </div>
665<h2><a href="http://www.imagemagick.org/api/MagickCore/enhance
666_8c.html" target="source" name="The NormalizeImage">The NormalizeImage</a></h2>
667<div class="doc-section">
668
669<p>The NormalizeImage() method enhances the contrast of a color image by mapping the darkest 2 percent of all pixel to black and the brightest 1 percent to white.</p></ol>
670
671<p>The format of the NormalizeImage method is:</p>
672
673<pre class="code">
674 MagickBooleanType NormalizeImage(Image *image)
675 MagickBooleanType NormalizeImageChannel(Image *image,
676 const ChannelType channel)
677</pre>
678
679<p>A description of each parameter follows:</p></ol>
680
681<h5>image</h5>
682<ol><p>the image.</p></ol>
683
684<h5>channel</h5>
685<ol><p>the channel.</p></ol>
686
687 </div>
688<h2><a href="http://www.imagemagick.org/api/MagickCore/enhance
689_8c.html" target="source" name="SigmoidalContrastImage">SigmoidalContrastImage</a></h2>
690<div class="doc-section">
691
692<p>SigmoidalContrastImage() adjusts the contrast of an image with a non-linear sigmoidal contrast algorithm. Increase the contrast of the image using a sigmoidal transfer function without saturating highlights or shadows. Contrast indicates how much to increase the contrast (0 is none; 3 is typical; 20 is pushing it); mid-point indicates where midtones fall in the resultant image (0 is white; 50 is middle-gray; 100 is black). Set sharpen to MagickTrue to increase the image contrast otherwise the contrast is reduced.</p></ol>
693
694<p>The format of the SigmoidalContrastImage method is:</p>
695
696<pre class="code">
697 MagickBooleanType SigmoidalContrastImage(Image *image,
698 const MagickBooleanType sharpen,const char *levels)
699 MagickBooleanType SigmoidalContrastImageChannel(Image *image,
700 const ChannelType channel,const MagickBooleanType sharpen,
701 const double contrast,const double midpoint)
702</pre>
703
704<p>A description of each parameter follows:</p></ol>
705
706<h5>image</h5>
707<ol><p>the image.</p></ol>
708
709<h5>channel</h5>
710<ol><p>the channel.</p></ol>
711
712<h5>sharpen</h5>
713<ol><p>Increase or decrease image contrast.</p></ol>
714
715<h5>contrast</h5>
716<ol><p>control the "shoulder" of the contast curve.</p></ol>
717
718<h5>midpoint</h5>
719<ol><p>control the "toe" of the contast curve.</p></ol>
720
721 </div>
cristy3eaa0ef2010-03-06 20:35:26 +0000[diff] [blame]722
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