2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
6 % QQQ U U AAA N N TTTTT IIIII ZZZZZ EEEEE %
7 % Q Q U U A A NN N T I ZZ E %
8 % Q Q U U AAAAA N N N T I ZZZ EEEEE %
9 % Q QQ U U A A N NN T I ZZ E %
10 % QQQQ UUU A A N N T IIIII ZZZZZ EEEEE %
13 % MagickCore Methods to Reduce the Number of Unique Colors in an Image %
20 % Copyright 1999-2012 ImageMagick Studio LLC, a non-profit organization %
21 % dedicated to making software imaging solutions freely available. %
23 % You may not use this file except in compliance with the License. You may %
24 % obtain a copy of the License at %
26 % http://www.imagemagick.org/script/license.php %
28 % Unless required by applicable law or agreed to in writing, software %
29 % distributed under the License is distributed on an "AS IS" BASIS, %
30 % WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. %
31 % See the License for the specific language governing permissions and %
32 % limitations under the License. %
34 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
36 % Realism in computer graphics typically requires using 24 bits/pixel to
37 % generate an image. Yet many graphic display devices do not contain the
38 % amount of memory necessary to match the spatial and color resolution of
39 % the human eye. The Quantize methods takes a 24 bit image and reduces
40 % the number of colors so it can be displayed on raster device with less
41 % bits per pixel. In most instances, the quantized image closely
42 % resembles the original reference image.
44 % A reduction of colors in an image is also desirable for image
45 % transmission and real-time animation.
47 % QuantizeImage() takes a standard RGB or monochrome images and quantizes
48 % them down to some fixed number of colors.
50 % For purposes of color allocation, an image is a set of n pixels, where
51 % each pixel is a point in RGB space. RGB space is a 3-dimensional
52 % vector space, and each pixel, Pi, is defined by an ordered triple of
53 % red, green, and blue coordinates, (Ri, Gi, Bi).
55 % Each primary color component (red, green, or blue) represents an
56 % intensity which varies linearly from 0 to a maximum value, Cmax, which
57 % corresponds to full saturation of that color. Color allocation is
58 % defined over a domain consisting of the cube in RGB space with opposite
59 % vertices at (0,0,0) and (Cmax, Cmax, Cmax). QUANTIZE requires Cmax =
62 % The algorithm maps this domain onto a tree in which each node
63 % represents a cube within that domain. In the following discussion
64 % these cubes are defined by the coordinate of two opposite vertices:
65 % The vertex nearest the origin in RGB space and the vertex farthest from
68 % The tree's root node represents the entire domain, (0,0,0) through
69 % (Cmax,Cmax,Cmax). Each lower level in the tree is generated by
70 % subdividing one node's cube into eight smaller cubes of equal size.
71 % This corresponds to bisecting the parent cube with planes passing
72 % through the midpoints of each edge.
74 % The basic algorithm operates in three phases: Classification,
75 % Reduction, and Assignment. Classification builds a color description
76 % tree for the image. Reduction collapses the tree until the number it
77 % represents, at most, the number of colors desired in the output image.
78 % Assignment defines the output image's color map and sets each pixel's
79 % color by restorage_class in the reduced tree. Our goal is to minimize
80 % the numerical discrepancies between the original colors and quantized
81 % colors (quantization error).
83 % Classification begins by initializing a color description tree of
84 % sufficient depth to represent each possible input color in a leaf.
85 % However, it is impractical to generate a fully-formed color description
86 % tree in the storage_class phase for realistic values of Cmax. If
87 % colors components in the input image are quantized to k-bit precision,
88 % so that Cmax= 2k-1, the tree would need k levels below the root node to
89 % allow representing each possible input color in a leaf. This becomes
90 % prohibitive because the tree's total number of nodes is 1 +
93 % A complete tree would require 19,173,961 nodes for k = 8, Cmax = 255.
94 % Therefore, to avoid building a fully populated tree, QUANTIZE: (1)
95 % Initializes data structures for nodes only as they are needed; (2)
96 % Chooses a maximum depth for the tree as a function of the desired
97 % number of colors in the output image (currently log2(colormap size)).
99 % For each pixel in the input image, storage_class scans downward from
100 % the root of the color description tree. At each level of the tree it
101 % identifies the single node which represents a cube in RGB space
102 % containing the pixel's color. It updates the following data for each
105 % n1: Number of pixels whose color is contained in the RGB cube which
106 % this node represents;
108 % n2: Number of pixels whose color is not represented in a node at
109 % lower depth in the tree; initially, n2 = 0 for all nodes except
110 % leaves of the tree.
112 % Sr, Sg, Sb: Sums of the red, green, and blue component values for all
113 % pixels not classified at a lower depth. The combination of these sums
114 % and n2 will ultimately characterize the mean color of a set of
115 % pixels represented by this node.
117 % E: the distance squared in RGB space between each pixel contained
118 % within a node and the nodes' center. This represents the
119 % quantization error for a node.
121 % Reduction repeatedly prunes the tree until the number of nodes with n2
122 % > 0 is less than or equal to the maximum number of colors allowed in
123 % the output image. On any given iteration over the tree, it selects
124 % those nodes whose E count is minimal for pruning and merges their color
125 % statistics upward. It uses a pruning threshold, Ep, to govern node
126 % selection as follows:
129 % while number of nodes with (n2 > 0) > required maximum number of colors
130 % prune all nodes such that E <= Ep
131 % Set Ep to minimum E in remaining nodes
133 % This has the effect of minimizing any quantization error when merging
134 % two nodes together.
136 % When a node to be pruned has offspring, the pruning procedure invokes
137 % itself recursively in order to prune the tree from the leaves upward.
138 % n2, Sr, Sg, and Sb in a node being pruned are always added to the
139 % corresponding data in that node's parent. This retains the pruned
140 % node's color characteristics for later averaging.
142 % For each node, n2 pixels exist for which that node represents the
143 % smallest volume in RGB space containing those pixel's colors. When n2
144 % > 0 the node will uniquely define a color in the output image. At the
145 % beginning of reduction, n2 = 0 for all nodes except a the leaves of
146 % the tree which represent colors present in the input image.
148 % The other pixel count, n1, indicates the total number of colors within
149 % the cubic volume which the node represents. This includes n1 - n2
150 % pixels whose colors should be defined by nodes at a lower level in the
153 % Assignment generates the output image from the pruned tree. The output
154 % image consists of two parts: (1) A color map, which is an array of
155 % color descriptions (RGB triples) for each color present in the output
156 % image; (2) A pixel array, which represents each pixel as an index
157 % into the color map array.
159 % First, the assignment phase makes one pass over the pruned color
160 % description tree to establish the image's color map. For each node
161 % with n2 > 0, it divides Sr, Sg, and Sb by n2 . This produces the mean
162 % color of all pixels that classify no lower than this node. Each of
163 % these colors becomes an entry in the color map.
165 % Finally, the assignment phase reclassifies each pixel in the pruned
166 % tree to identify the deepest node containing the pixel's color. The
167 % pixel's value in the pixel array becomes the index of this node's mean
168 % color in the color map.
170 % This method is based on a similar algorithm written by Paul Raveling.
175 Include declarations.
177 #include "MagickCore/studio.h"
178 #include "MagickCore/attribute.h"
179 #include "MagickCore/cache-view.h"
180 #include "MagickCore/color.h"
181 #include "MagickCore/color-private.h"
182 #include "MagickCore/colormap.h"
183 #include "MagickCore/colorspace.h"
184 #include "MagickCore/colorspace-private.h"
185 #include "MagickCore/enhance.h"
186 #include "MagickCore/exception.h"
187 #include "MagickCore/exception-private.h"
188 #include "MagickCore/histogram.h"
189 #include "MagickCore/image.h"
190 #include "MagickCore/image-private.h"
191 #include "MagickCore/list.h"
192 #include "MagickCore/memory_.h"
193 #include "MagickCore/monitor.h"
194 #include "MagickCore/monitor-private.h"
195 #include "MagickCore/option.h"
196 #include "MagickCore/pixel-accessor.h"
197 #include "MagickCore/pixel-private.h"
198 #include "MagickCore/quantize.h"
199 #include "MagickCore/quantum.h"
200 #include "MagickCore/quantum-private.h"
201 #include "MagickCore/resource_.h"
202 #include "MagickCore/string_.h"
203 #include "MagickCore/thread-private.h"
208 #if !defined(__APPLE__) && !defined(TARGET_OS_IPHONE)
213 #define ErrorQueueLength 16
214 #define MaxNodes 266817
215 #define MaxTreeDepth 8
216 #define NodesInAList 1920
221 typedef struct _RealPixelInfo
230 typedef struct _NodeInfo
251 typedef struct _Nodes
260 typedef struct _CubeInfo
298 error[ErrorQueueLength];
301 weights[ErrorQueueLength];
327 *GetCubeInfo(const QuantizeInfo *,const size_t,const size_t);
330 *GetNodeInfo(CubeInfo *,const size_t,const size_t,NodeInfo *);
332 static MagickBooleanType
333 AssignImageColors(Image *,CubeInfo *,ExceptionInfo *),
334 ClassifyImageColors(CubeInfo *,const Image *,ExceptionInfo *),
335 DitherImage(Image *,CubeInfo *,ExceptionInfo *),
336 SetGrayscaleImage(Image *,ExceptionInfo *);
339 DefineImageColormap(Image *,CubeInfo *,NodeInfo *);
342 ClosestColor(const Image *,CubeInfo *,const NodeInfo *),
343 DestroyCubeInfo(CubeInfo *),
344 PruneLevel(const Image *,CubeInfo *,const NodeInfo *),
345 PruneToCubeDepth(const Image *,CubeInfo *,const NodeInfo *),
346 ReduceImageColors(const Image *,CubeInfo *);
349 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
353 % A c q u i r e Q u a n t i z e I n f o %
357 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
359 % AcquireQuantizeInfo() allocates the QuantizeInfo structure.
361 % The format of the AcquireQuantizeInfo method is:
363 % QuantizeInfo *AcquireQuantizeInfo(const ImageInfo *image_info)
365 % A description of each parameter follows:
367 % o image_info: the image info.
370 MagickExport QuantizeInfo *AcquireQuantizeInfo(const ImageInfo *image_info)
375 quantize_info=(QuantizeInfo *) AcquireMagickMemory(sizeof(*quantize_info));
376 if (quantize_info == (QuantizeInfo *) NULL)
377 ThrowFatalException(ResourceLimitFatalError,"MemoryAllocationFailed");
378 GetQuantizeInfo(quantize_info);
379 if (image_info != (ImageInfo *) NULL)
384 quantize_info->dither_method=image_info->dither == MagickFalse ?
385 NoDitherMethod : RiemersmaDitherMethod;
386 option=GetImageOption(image_info,"dither");
387 if (option != (const char *) NULL)
388 quantize_info->dither_method=(DitherMethod) ParseCommandOption(
389 MagickDitherOptions,MagickFalse,option);
390 quantize_info->measure_error=image_info->verbose;
392 return(quantize_info);
396 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
400 + A s s i g n I m a g e C o l o r s %
404 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
406 % AssignImageColors() generates the output image from the pruned tree. The
407 % output image consists of two parts: (1) A color map, which is an array
408 % of color descriptions (RGB triples) for each color present in the
409 % output image; (2) A pixel array, which represents each pixel as an
410 % index into the color map array.
412 % First, the assignment phase makes one pass over the pruned color
413 % description tree to establish the image's color map. For each node
414 % with n2 > 0, it divides Sr, Sg, and Sb by n2 . This produces the mean
415 % color of all pixels that classify no lower than this node. Each of
416 % these colors becomes an entry in the color map.
418 % Finally, the assignment phase reclassifies each pixel in the pruned
419 % tree to identify the deepest node containing the pixel's color. The
420 % pixel's value in the pixel array becomes the index of this node's mean
421 % color in the color map.
423 % The format of the AssignImageColors() method is:
425 % MagickBooleanType AssignImageColors(Image *image,CubeInfo *cube_info)
427 % A description of each parameter follows.
429 % o image: the image.
431 % o cube_info: A pointer to the Cube structure.
435 static inline void AssociateAlphaPixel(const Image *image,
436 const CubeInfo *cube_info,const Quantum *pixel,RealPixelInfo *alpha_pixel)
441 if ((cube_info->associate_alpha == MagickFalse) ||
442 (GetPixelAlpha(image,pixel)== OpaqueAlpha))
444 alpha_pixel->red=(double) GetPixelRed(image,pixel);
445 alpha_pixel->green=(double) GetPixelGreen(image,pixel);
446 alpha_pixel->blue=(double) GetPixelBlue(image,pixel);
447 alpha_pixel->alpha=(double) GetPixelAlpha(image,pixel);
450 alpha=(double) (QuantumScale*GetPixelAlpha(image,pixel));
451 alpha_pixel->red=alpha*GetPixelRed(image,pixel);
452 alpha_pixel->green=alpha*GetPixelGreen(image,pixel);
453 alpha_pixel->blue=alpha*GetPixelBlue(image,pixel);
454 alpha_pixel->alpha=(double) GetPixelAlpha(image,pixel);
457 static inline void AssociateAlphaPixelInfo(const Image *image,
458 const CubeInfo *cube_info,const PixelInfo *pixel,
459 RealPixelInfo *alpha_pixel)
464 if ((cube_info->associate_alpha == MagickFalse) ||
465 (pixel->alpha == OpaqueAlpha))
467 alpha_pixel->red=(double) pixel->red;
468 alpha_pixel->green=(double) pixel->green;
469 alpha_pixel->blue=(double) pixel->blue;
470 alpha_pixel->alpha=(double) pixel->alpha;
473 alpha=(double) (QuantumScale*pixel->alpha);
474 alpha_pixel->red=alpha*pixel->red;
475 alpha_pixel->green=alpha*pixel->green;
476 alpha_pixel->blue=alpha*pixel->blue;
477 alpha_pixel->alpha=(double) pixel->alpha;
480 static inline Quantum ClampToUnsignedQuantum(const double value)
484 if (value >= QuantumRange)
485 return(QuantumRange);
486 return((Quantum) (value+0.5));
489 static inline size_t ColorToNodeId(const CubeInfo *cube_info,
490 const RealPixelInfo *pixel,size_t index)
495 id=(size_t) (((ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->red)) >> index) & 0x01) |
496 ((ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->green)) >> index) & 0x01) << 1 |
497 ((ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->blue)) >> index) & 0x01) << 2);
498 if (cube_info->associate_alpha != MagickFalse)
499 id|=((ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->alpha)) >> index) & 0x1) << 3;
503 static MagickBooleanType AssignImageColors(Image *image,CubeInfo *cube_info,
504 ExceptionInfo *exception)
506 #define AssignImageTag "Assign/Image"
512 Allocate image colormap.
514 if ((cube_info->quantize_info->colorspace != UndefinedColorspace) &&
515 (cube_info->quantize_info->colorspace != CMYKColorspace))
516 (void) TransformImageColorspace((Image *) image,
517 cube_info->quantize_info->colorspace,exception);
519 if (IssRGBCompatibleColorspace(image->colorspace) == MagickFalse)
520 (void) TransformImageColorspace((Image *) image,sRGBColorspace,exception);
521 if (AcquireImageColormap(image,cube_info->colors,exception) == MagickFalse)
522 ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
525 cube_info->transparent_pixels=0;
526 cube_info->transparent_index=(-1);
527 (void) DefineImageColormap(image,cube_info,cube_info->root);
529 Create a reduced color image.
531 if ((cube_info->quantize_info->dither_method != NoDitherMethod) &&
532 (cube_info->quantize_info->dither_method != NoDitherMethod))
533 (void) DitherImage(image,cube_info,exception);
543 image_view=AcquireAuthenticCacheView(image,exception);
544 #if defined(MAGICKCORE_OPENMP_SUPPORT)
545 #pragma omp parallel for schedule(static,4) shared(status) \
546 dynamic_number_threads(image,image->columns,image->rows,1)
548 for (y=0; y < (ssize_t) image->rows; y++)
562 if (status == MagickFalse)
564 q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,
566 if (q == (Quantum *) NULL)
572 for (x=0; x < (ssize_t) image->columns; x+=count)
577 register const NodeInfo
588 Identify the deepest node containing the pixel's color.
590 for (count=1; (x+count) < (ssize_t) image->columns; count++)
595 GetPixelInfoPixel(image,q+count*GetPixelChannels(image),&packet);
596 if (IsPixelEquivalent(image,q,&packet) == MagickFalse)
599 AssociateAlphaPixel(image,&cube,q,&pixel);
601 for (index=MaxTreeDepth-1; (ssize_t) index > 0; index--)
603 id=ColorToNodeId(&cube,&pixel,index);
604 if (node_info->child[id] == (NodeInfo *) NULL)
606 node_info=node_info->child[id];
609 Find closest color among siblings and their children.
612 cube.distance=(double) (4.0*(QuantumRange+1.0)*
613 (QuantumRange+1.0)+1.0);
614 ClosestColor(image,&cube,node_info->parent);
615 index=cube.color_number;
616 for (i=0; i < (ssize_t) count; i++)
618 if (image->storage_class == PseudoClass)
619 SetPixelIndex(image,(Quantum) index,q);
620 if (cube.quantize_info->measure_error == MagickFalse)
622 SetPixelRed(image,ClampToQuantum(
623 image->colormap[index].red),q);
624 SetPixelGreen(image,ClampToQuantum(
625 image->colormap[index].green),q);
626 SetPixelBlue(image,ClampToQuantum(
627 image->colormap[index].blue),q);
628 if (cube.associate_alpha != MagickFalse)
629 SetPixelAlpha(image,ClampToQuantum(
630 image->colormap[index].alpha),q);
632 q+=GetPixelChannels(image);
635 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
637 if (image->progress_monitor != (MagickProgressMonitor) NULL)
642 #if defined(MAGICKCORE_OPENMP_SUPPORT)
643 #pragma omp critical (MagickCore_AssignImageColors)
645 proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) y,
647 if (proceed == MagickFalse)
651 image_view=DestroyCacheView(image_view);
653 if (cube_info->quantize_info->measure_error != MagickFalse)
654 (void) GetImageQuantizeError(image,exception);
655 if ((cube_info->quantize_info->number_colors == 2) &&
656 (cube_info->quantize_info->colorspace == GRAYColorspace))
671 for (i=0; i < (ssize_t) image->colors; i++)
673 intensity=(double) ((double) GetPixelInfoIntensity(q) <
674 ((double) QuantumRange/2.0) ? 0 : QuantumRange);
681 (void) SyncImage(image,exception);
682 if ((cube_info->quantize_info->colorspace != UndefinedColorspace) &&
683 (cube_info->quantize_info->colorspace != CMYKColorspace))
684 (void) TransformImageColorspace((Image *) image,sRGBColorspace,exception);
689 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
693 + C l a s s i f y I m a g e C o l o r s %
697 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
699 % ClassifyImageColors() begins by initializing a color description tree
700 % of sufficient depth to represent each possible input color in a leaf.
701 % However, it is impractical to generate a fully-formed color
702 % description tree in the storage_class phase for realistic values of
703 % Cmax. If colors components in the input image are quantized to k-bit
704 % precision, so that Cmax= 2k-1, the tree would need k levels below the
705 % root node to allow representing each possible input color in a leaf.
706 % This becomes prohibitive because the tree's total number of nodes is
709 % A complete tree would require 19,173,961 nodes for k = 8, Cmax = 255.
710 % Therefore, to avoid building a fully populated tree, QUANTIZE: (1)
711 % Initializes data structures for nodes only as they are needed; (2)
712 % Chooses a maximum depth for the tree as a function of the desired
713 % number of colors in the output image (currently log2(colormap size)).
715 % For each pixel in the input image, storage_class scans downward from
716 % the root of the color description tree. At each level of the tree it
717 % identifies the single node which represents a cube in RGB space
718 % containing It updates the following data for each such node:
720 % n1 : Number of pixels whose color is contained in the RGB cube
721 % which this node represents;
723 % n2 : Number of pixels whose color is not represented in a node at
724 % lower depth in the tree; initially, n2 = 0 for all nodes except
725 % leaves of the tree.
727 % Sr, Sg, Sb : Sums of the red, green, and blue component values for
728 % all pixels not classified at a lower depth. The combination of
729 % these sums and n2 will ultimately characterize the mean color of a
730 % set of pixels represented by this node.
732 % E: the distance squared in RGB space between each pixel contained
733 % within a node and the nodes' center. This represents the quantization
736 % The format of the ClassifyImageColors() method is:
738 % MagickBooleanType ClassifyImageColors(CubeInfo *cube_info,
739 % const Image *image,ExceptionInfo *exception)
741 % A description of each parameter follows.
743 % o cube_info: A pointer to the Cube structure.
745 % o image: the image.
749 static inline void SetAssociatedAlpha(const Image *image,CubeInfo *cube_info)
754 associate_alpha=image->matte;
755 if (cube_info->quantize_info->colorspace == TransparentColorspace)
756 associate_alpha=MagickFalse;
757 if ((cube_info->quantize_info->number_colors == 2) &&
758 (cube_info->quantize_info->colorspace == GRAYColorspace))
759 associate_alpha=MagickFalse;
760 cube_info->associate_alpha=associate_alpha;
763 static MagickBooleanType ClassifyImageColors(CubeInfo *cube_info,
764 const Image *image,ExceptionInfo *exception)
766 #define ClassifyImageTag "Classify/Image"
796 Classify the first cube_info->maximum_colors colors to a tree depth of 8.
798 SetAssociatedAlpha(image,cube_info);
799 if ((cube_info->quantize_info->colorspace != UndefinedColorspace) &&
800 (cube_info->quantize_info->colorspace != CMYKColorspace))
801 (void) TransformImageColorspace((Image *) image,
802 cube_info->quantize_info->colorspace,exception);
804 if (IssRGBCompatibleColorspace(image->colorspace) == MagickFalse)
805 (void) TransformImageColorspace((Image *) image,sRGBColorspace,exception);
806 midpoint.red=(double) QuantumRange/2.0;
807 midpoint.green=(double) QuantumRange/2.0;
808 midpoint.blue=(double) QuantumRange/2.0;
809 midpoint.alpha=(double) QuantumRange/2.0;
811 image_view=AcquireVirtualCacheView(image,exception);
812 for (y=0; y < (ssize_t) image->rows; y++)
814 register const Quantum
820 p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
821 if (p == (const Quantum *) NULL)
823 if (cube_info->nodes > MaxNodes)
826 Prune one level if the color tree is too large.
828 PruneLevel(image,cube_info,cube_info->root);
831 for (x=0; x < (ssize_t) image->columns; x+=(ssize_t) count)
834 Start at the root and descend the color cube tree.
836 for (count=1; (x+(ssize_t) count) < (ssize_t) image->columns; count++)
841 GetPixelInfoPixel(image,p+count*GetPixelChannels(image),&packet);
842 if (IsPixelEquivalent(image,p,&packet) == MagickFalse)
845 AssociateAlphaPixel(image,cube_info,p,&pixel);
846 index=MaxTreeDepth-1;
847 bisect=((double) QuantumRange+1.0)/2.0;
849 node_info=cube_info->root;
850 for (level=1; level <= MaxTreeDepth; level++)
853 id=ColorToNodeId(cube_info,&pixel,index);
854 mid.red+=(id & 1) != 0 ? bisect : -bisect;
855 mid.green+=(id & 2) != 0 ? bisect : -bisect;
856 mid.blue+=(id & 4) != 0 ? bisect : -bisect;
857 mid.alpha+=(id & 8) != 0 ? bisect : -bisect;
858 if (node_info->child[id] == (NodeInfo *) NULL)
861 Set colors of new node to contain pixel.
863 node_info->child[id]=GetNodeInfo(cube_info,id,level,node_info);
864 if (node_info->child[id] == (NodeInfo *) NULL)
865 (void) ThrowMagickException(exception,GetMagickModule(),
866 ResourceLimitError,"MemoryAllocationFailed","'%s'",
868 if (level == MaxTreeDepth)
872 Approximate the quantization error represented by this node.
874 node_info=node_info->child[id];
875 error.red=QuantumScale*(pixel.red-mid.red);
876 error.green=QuantumScale*(pixel.green-mid.green);
877 error.blue=QuantumScale*(pixel.blue-mid.blue);
878 if (cube_info->associate_alpha != MagickFalse)
879 error.alpha=QuantumScale*(pixel.alpha-mid.alpha);
880 node_info->quantize_error+=sqrt((double) (count*error.red*error.red+
881 count*error.green*error.green+count*error.blue*error.blue+
882 count*error.alpha*error.alpha));
883 cube_info->root->quantize_error+=node_info->quantize_error;
887 Sum RGB for this leaf for later derivation of the mean cube color.
889 node_info->number_unique+=count;
890 node_info->total_color.red+=count*QuantumScale*pixel.red;
891 node_info->total_color.green+=count*QuantumScale*pixel.green;
892 node_info->total_color.blue+=count*QuantumScale*pixel.blue;
893 if (cube_info->associate_alpha != MagickFalse)
894 node_info->total_color.alpha+=count*QuantumScale*pixel.alpha;
895 p+=count*GetPixelChannels(image);
897 if (cube_info->colors > cube_info->maximum_colors)
899 PruneToCubeDepth(image,cube_info,cube_info->root);
902 proceed=SetImageProgress(image,ClassifyImageTag,(MagickOffsetType) y,
904 if (proceed == MagickFalse)
907 for (y++; y < (ssize_t) image->rows; y++)
909 register const Quantum
915 p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
916 if (p == (const Quantum *) NULL)
918 if (cube_info->nodes > MaxNodes)
921 Prune one level if the color tree is too large.
923 PruneLevel(image,cube_info,cube_info->root);
926 for (x=0; x < (ssize_t) image->columns; x+=(ssize_t) count)
929 Start at the root and descend the color cube tree.
931 for (count=1; (x+(ssize_t) count) < (ssize_t) image->columns; count++)
936 GetPixelInfoPixel(image,p+count*GetPixelChannels(image),&packet);
937 if (IsPixelEquivalent(image,p,&packet) == MagickFalse)
940 AssociateAlphaPixel(image,cube_info,p,&pixel);
941 index=MaxTreeDepth-1;
942 bisect=((double) QuantumRange+1.0)/2.0;
944 node_info=cube_info->root;
945 for (level=1; level <= cube_info->depth; level++)
948 id=ColorToNodeId(cube_info,&pixel,index);
949 mid.red+=(id & 1) != 0 ? bisect : -bisect;
950 mid.green+=(id & 2) != 0 ? bisect : -bisect;
951 mid.blue+=(id & 4) != 0 ? bisect : -bisect;
952 mid.alpha+=(id & 8) != 0 ? bisect : -bisect;
953 if (node_info->child[id] == (NodeInfo *) NULL)
956 Set colors of new node to contain pixel.
958 node_info->child[id]=GetNodeInfo(cube_info,id,level,node_info);
959 if (node_info->child[id] == (NodeInfo *) NULL)
960 (void) ThrowMagickException(exception,GetMagickModule(),
961 ResourceLimitError,"MemoryAllocationFailed","%s",
963 if (level == cube_info->depth)
967 Approximate the quantization error represented by this node.
969 node_info=node_info->child[id];
970 error.red=QuantumScale*(pixel.red-mid.red);
971 error.green=QuantumScale*(pixel.green-mid.green);
972 error.blue=QuantumScale*(pixel.blue-mid.blue);
973 if (cube_info->associate_alpha != MagickFalse)
974 error.alpha=QuantumScale*(pixel.alpha-mid.alpha);
975 node_info->quantize_error+=sqrt((double) (count*error.red*error.red+
976 count*error.green*error.green+count*error.blue*error.blue+
977 count*error.alpha*error.alpha));
978 cube_info->root->quantize_error+=node_info->quantize_error;
982 Sum RGB for this leaf for later derivation of the mean cube color.
984 node_info->number_unique+=count;
985 node_info->total_color.red+=count*QuantumScale*pixel.red;
986 node_info->total_color.green+=count*QuantumScale*pixel.green;
987 node_info->total_color.blue+=count*QuantumScale*pixel.blue;
988 if (cube_info->associate_alpha != MagickFalse)
989 node_info->total_color.alpha+=count*QuantumScale*pixel.alpha;
990 p+=count*GetPixelChannels(image);
992 proceed=SetImageProgress(image,ClassifyImageTag,(MagickOffsetType) y,
994 if (proceed == MagickFalse)
997 image_view=DestroyCacheView(image_view);
998 if ((cube_info->quantize_info->colorspace != UndefinedColorspace) &&
999 (cube_info->quantize_info->colorspace != CMYKColorspace))
1000 (void) TransformImageColorspace((Image *) image,sRGBColorspace,exception);
1005 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1009 % C l o n e Q u a n t i z e I n f o %
1013 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1015 % CloneQuantizeInfo() makes a duplicate of the given quantize info structure,
1016 % or if quantize info is NULL, a new one.
1018 % The format of the CloneQuantizeInfo method is:
1020 % QuantizeInfo *CloneQuantizeInfo(const QuantizeInfo *quantize_info)
1022 % A description of each parameter follows:
1024 % o clone_info: Method CloneQuantizeInfo returns a duplicate of the given
1025 % quantize info, or if image info is NULL a new one.
1027 % o quantize_info: a structure of type info.
1030 MagickExport QuantizeInfo *CloneQuantizeInfo(const QuantizeInfo *quantize_info)
1035 clone_info=(QuantizeInfo *) AcquireMagickMemory(sizeof(*clone_info));
1036 if (clone_info == (QuantizeInfo *) NULL)
1037 ThrowFatalException(ResourceLimitFatalError,"MemoryAllocationFailed");
1038 GetQuantizeInfo(clone_info);
1039 if (quantize_info == (QuantizeInfo *) NULL)
1041 clone_info->number_colors=quantize_info->number_colors;
1042 clone_info->tree_depth=quantize_info->tree_depth;
1043 clone_info->dither_method=quantize_info->dither_method;
1044 clone_info->colorspace=quantize_info->colorspace;
1045 clone_info->measure_error=quantize_info->measure_error;
1050 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1054 + C l o s e s t C o l o r %
1058 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1060 % ClosestColor() traverses the color cube tree at a particular node and
1061 % determines which colormap entry best represents the input color.
1063 % The format of the ClosestColor method is:
1065 % void ClosestColor(const Image *image,CubeInfo *cube_info,
1066 % const NodeInfo *node_info)
1068 % A description of each parameter follows.
1070 % o image: the image.
1072 % o cube_info: A pointer to the Cube structure.
1074 % o node_info: the address of a structure of type NodeInfo which points to a
1075 % node in the color cube tree that is to be pruned.
1078 static void ClosestColor(const Image *image,CubeInfo *cube_info,
1079 const NodeInfo *node_info)
1088 Traverse any children.
1090 number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
1091 for (i=0; i < (ssize_t) number_children; i++)
1092 if (node_info->child[i] != (NodeInfo *) NULL)
1093 ClosestColor(image,cube_info,node_info->child[i]);
1094 if (node_info->number_unique != 0)
1107 register RealPixelInfo
1111 Determine if this color is "closest".
1113 p=image->colormap+node_info->color_number;
1114 q=(&cube_info->target);
1117 if (cube_info->associate_alpha != MagickFalse)
1119 alpha=(double) (QuantumScale*p->alpha);
1120 beta=(double) (QuantumScale*q->alpha);
1122 pixel=alpha*p->red-beta*q->red;
1123 distance=pixel*pixel;
1124 if (distance <= cube_info->distance)
1126 pixel=alpha*p->green-beta*q->green;
1127 distance+=pixel*pixel;
1128 if (distance <= cube_info->distance)
1130 pixel=alpha*p->blue-beta*q->blue;
1131 distance+=pixel*pixel;
1132 if (distance <= cube_info->distance)
1135 distance+=pixel*pixel;
1136 if (distance <= cube_info->distance)
1138 cube_info->distance=distance;
1139 cube_info->color_number=node_info->color_number;
1148 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1152 % C o m p r e s s I m a g e C o l o r m a p %
1156 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1158 % CompressImageColormap() compresses an image colormap by removing any
1159 % duplicate or unused color entries.
1161 % The format of the CompressImageColormap method is:
1163 % MagickBooleanType CompressImageColormap(Image *image,
1164 % ExceptionInfo *exception)
1166 % A description of each parameter follows:
1168 % o image: the image.
1170 % o exception: return any errors or warnings in this structure.
1173 MagickExport MagickBooleanType CompressImageColormap(Image *image,
1174 ExceptionInfo *exception)
1179 assert(image != (Image *) NULL);
1180 assert(image->signature == MagickSignature);
1181 if (image->debug != MagickFalse)
1182 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1183 if (IsPaletteImage(image,exception) == MagickFalse)
1184 return(MagickFalse);
1185 GetQuantizeInfo(&quantize_info);
1186 quantize_info.number_colors=image->colors;
1187 quantize_info.tree_depth=MaxTreeDepth;
1188 return(QuantizeImage(&quantize_info,image,exception));
1192 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1196 + D e f i n e I m a g e C o l o r m a p %
1200 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1202 % DefineImageColormap() traverses the color cube tree and notes each colormap
1203 % entry. A colormap entry is any node in the color cube tree where the
1204 % of unique colors is not zero. DefineImageColormap() returns the number of
1205 % colors in the image colormap.
1207 % The format of the DefineImageColormap method is:
1209 % size_t DefineImageColormap(Image *image,CubeInfo *cube_info,
1210 % NodeInfo *node_info)
1212 % A description of each parameter follows.
1214 % o image: the image.
1216 % o cube_info: A pointer to the Cube structure.
1218 % o node_info: the address of a structure of type NodeInfo which points to a
1219 % node in the color cube tree that is to be pruned.
1222 static size_t DefineImageColormap(Image *image,CubeInfo *cube_info,
1223 NodeInfo *node_info)
1232 Traverse any children.
1234 number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
1235 for (i=0; i < (ssize_t) number_children; i++)
1236 if (node_info->child[i] != (NodeInfo *) NULL)
1237 (void) DefineImageColormap(image,cube_info,node_info->child[i]);
1238 if (node_info->number_unique != 0)
1247 Colormap entry is defined by the mean color in this cube.
1249 q=image->colormap+image->colors;
1250 alpha=(double) ((MagickOffsetType) node_info->number_unique);
1251 alpha=MagickEpsilonReciprocal(alpha);
1252 if (cube_info->associate_alpha == MagickFalse)
1254 q->red=(double) ClampToQuantum(alpha*QuantumRange*
1255 node_info->total_color.red);
1256 q->green=(double) ClampToQuantum(alpha*QuantumRange*
1257 node_info->total_color.green);
1258 q->blue=(double) ClampToQuantum(alpha*(double) QuantumRange*
1259 node_info->total_color.blue);
1260 q->alpha=OpaqueAlpha;
1267 opacity=(double) (alpha*QuantumRange*
1268 node_info->total_color.alpha);
1269 q->alpha=(double) ClampToQuantum(opacity);
1270 if (q->alpha == OpaqueAlpha)
1272 q->red=(double) ClampToQuantum(alpha*QuantumRange*
1273 node_info->total_color.red);
1274 q->green=(double) ClampToQuantum(alpha*QuantumRange*
1275 node_info->total_color.green);
1276 q->blue=(double) ClampToQuantum(alpha*QuantumRange*
1277 node_info->total_color.blue);
1284 gamma=(double) (QuantumScale*q->alpha);
1285 gamma=MagickEpsilonReciprocal(gamma);
1286 q->red=(double) ClampToQuantum(alpha*gamma*QuantumRange*
1287 node_info->total_color.red);
1288 q->green=(double) ClampToQuantum(alpha*gamma*QuantumRange*
1289 node_info->total_color.green);
1290 q->blue=(double) ClampToQuantum(alpha*gamma*QuantumRange*
1291 node_info->total_color.blue);
1292 if (node_info->number_unique > cube_info->transparent_pixels)
1294 cube_info->transparent_pixels=node_info->number_unique;
1295 cube_info->transparent_index=(ssize_t) image->colors;
1299 node_info->color_number=image->colors++;
1301 return(image->colors);
1305 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1309 + D e s t r o y C u b e I n f o %
1313 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1315 % DestroyCubeInfo() deallocates memory associated with an image.
1317 % The format of the DestroyCubeInfo method is:
1319 % DestroyCubeInfo(CubeInfo *cube_info)
1321 % A description of each parameter follows:
1323 % o cube_info: the address of a structure of type CubeInfo.
1326 static void DestroyCubeInfo(CubeInfo *cube_info)
1332 Release color cube tree storage.
1336 nodes=cube_info->node_queue->next;
1337 cube_info->node_queue->nodes=(NodeInfo *) RelinquishMagickMemory(
1338 cube_info->node_queue->nodes);
1339 cube_info->node_queue=(Nodes *) RelinquishMagickMemory(
1340 cube_info->node_queue);
1341 cube_info->node_queue=nodes;
1342 } while (cube_info->node_queue != (Nodes *) NULL);
1343 if (cube_info->cache != (ssize_t *) NULL)
1344 cube_info->cache=(ssize_t *) RelinquishMagickMemory(cube_info->cache);
1345 cube_info->quantize_info=DestroyQuantizeInfo(cube_info->quantize_info);
1346 cube_info=(CubeInfo *) RelinquishMagickMemory(cube_info);
1350 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1354 % D e s t r o y Q u a n t i z e I n f o %
1358 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1360 % DestroyQuantizeInfo() deallocates memory associated with an QuantizeInfo
1363 % The format of the DestroyQuantizeInfo method is:
1365 % QuantizeInfo *DestroyQuantizeInfo(QuantizeInfo *quantize_info)
1367 % A description of each parameter follows:
1369 % o quantize_info: Specifies a pointer to an QuantizeInfo structure.
1372 MagickExport QuantizeInfo *DestroyQuantizeInfo(QuantizeInfo *quantize_info)
1374 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"...");
1375 assert(quantize_info != (QuantizeInfo *) NULL);
1376 assert(quantize_info->signature == MagickSignature);
1377 quantize_info->signature=(~MagickSignature);
1378 quantize_info=(QuantizeInfo *) RelinquishMagickMemory(quantize_info);
1379 return(quantize_info);
1383 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1387 + D i t h e r I m a g e %
1391 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1393 % DitherImage() distributes the difference between an original image and
1394 % the corresponding color reduced algorithm to neighboring pixels using
1395 % serpentine-scan Floyd-Steinberg error diffusion. DitherImage returns
1396 % MagickTrue if the image is dithered otherwise MagickFalse.
1398 % The format of the DitherImage method is:
1400 % MagickBooleanType DitherImage(Image *image,CubeInfo *cube_info,
1401 % ExceptionInfo *exception)
1403 % A description of each parameter follows.
1405 % o image: the image.
1407 % o cube_info: A pointer to the Cube structure.
1409 % o exception: return any errors or warnings in this structure.
1413 static RealPixelInfo **DestroyPixelThreadSet(RealPixelInfo **pixels)
1418 assert(pixels != (RealPixelInfo **) NULL);
1419 for (i=0; i < (ssize_t) GetMagickResourceLimit(ThreadResource); i++)
1420 if (pixels[i] != (RealPixelInfo *) NULL)
1421 pixels[i]=(RealPixelInfo *) RelinquishMagickMemory(pixels[i]);
1422 pixels=(RealPixelInfo **) RelinquishMagickMemory(pixels);
1426 static RealPixelInfo **AcquirePixelThreadSet(const size_t count)
1437 number_threads=(size_t) GetMagickResourceLimit(ThreadResource);
1438 pixels=(RealPixelInfo **) AcquireQuantumMemory(number_threads,
1440 if (pixels == (RealPixelInfo **) NULL)
1441 return((RealPixelInfo **) NULL);
1442 (void) ResetMagickMemory(pixels,0,number_threads*sizeof(*pixels));
1443 for (i=0; i < (ssize_t) number_threads; i++)
1445 pixels[i]=(RealPixelInfo *) AcquireQuantumMemory(count,
1446 2*sizeof(**pixels));
1447 if (pixels[i] == (RealPixelInfo *) NULL)
1448 return(DestroyPixelThreadSet(pixels));
1453 static inline ssize_t CacheOffset(CubeInfo *cube_info,
1454 const RealPixelInfo *pixel)
1456 #define RedShift(pixel) (((pixel) >> CacheShift) << (0*(8-CacheShift)))
1457 #define GreenShift(pixel) (((pixel) >> CacheShift) << (1*(8-CacheShift)))
1458 #define BlueShift(pixel) (((pixel) >> CacheShift) << (2*(8-CacheShift)))
1459 #define AlphaShift(pixel) (((pixel) >> CacheShift) << (3*(8-CacheShift)))
1465 (RedShift(ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->red))) |
1466 GreenShift(ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->green))) |
1467 BlueShift(ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->blue))));
1468 if (cube_info->associate_alpha != MagickFalse)
1469 offset|=AlphaShift(ScaleQuantumToChar(ClampToUnsignedQuantum(
1474 static MagickBooleanType FloydSteinbergDither(Image *image,CubeInfo *cube_info,
1475 ExceptionInfo *exception)
1477 #define DitherImageTag "Dither/Image"
1492 Distribute quantization error using Floyd-Steinberg.
1494 pixels=AcquirePixelThreadSet(image->columns);
1495 if (pixels == (RealPixelInfo **) NULL)
1496 return(MagickFalse);
1498 image_view=AcquireAuthenticCacheView(image,exception);
1499 for (y=0; y < (ssize_t) image->rows; y++)
1502 id = GetOpenMPThreadId();
1523 if (status == MagickFalse)
1525 q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
1526 if (q == (Quantum *) NULL)
1531 q+=(y & 0x01)*image->columns*GetPixelChannels(image);
1533 current=pixels[id]+(y & 0x01)*image->columns;
1534 previous=pixels[id]+((y+1) & 0x01)*image->columns;
1535 v=(ssize_t) ((y & 0x01) != 0 ? -1 : 1);
1536 for (x=0; x < (ssize_t) image->columns; x++)
1548 q-=(y & 0x01)*GetPixelChannels(image);
1549 u=(y & 0x01) != 0 ? (ssize_t) image->columns-1-x : x;
1550 AssociateAlphaPixel(image,&cube,q,&pixel);
1553 pixel.red+=7*current[u-v].red/16;
1554 pixel.green+=7*current[u-v].green/16;
1555 pixel.blue+=7*current[u-v].blue/16;
1556 if (cube.associate_alpha != MagickFalse)
1557 pixel.alpha+=7*current[u-v].alpha/16;
1561 if (x < (ssize_t) (image->columns-1))
1563 pixel.red+=previous[u+v].red/16;
1564 pixel.green+=previous[u+v].green/16;
1565 pixel.blue+=previous[u+v].blue/16;
1566 if (cube.associate_alpha != MagickFalse)
1567 pixel.alpha+=previous[u+v].alpha/16;
1569 pixel.red+=5*previous[u].red/16;
1570 pixel.green+=5*previous[u].green/16;
1571 pixel.blue+=5*previous[u].blue/16;
1572 if (cube.associate_alpha != MagickFalse)
1573 pixel.alpha+=5*previous[u].alpha/16;
1576 pixel.red+=3*previous[u-v].red/16;
1577 pixel.green+=3*previous[u-v].green/16;
1578 pixel.blue+=3*previous[u-v].blue/16;
1579 if (cube.associate_alpha != MagickFalse)
1580 pixel.alpha+=3*previous[u-v].alpha/16;
1583 pixel.red=(double) ClampToUnsignedQuantum(pixel.red);
1584 pixel.green=(double) ClampToUnsignedQuantum(pixel.green);
1585 pixel.blue=(double) ClampToUnsignedQuantum(pixel.blue);
1586 if (cube.associate_alpha != MagickFalse)
1587 pixel.alpha=(double) ClampToUnsignedQuantum(pixel.alpha);
1588 i=CacheOffset(&cube,&pixel);
1589 if (cube.cache[i] < 0)
1598 Identify the deepest node containing the pixel's color.
1600 node_info=cube.root;
1601 for (index=MaxTreeDepth-1; (ssize_t) index > 0; index--)
1603 id=ColorToNodeId(&cube,&pixel,index);
1604 if (node_info->child[id] == (NodeInfo *) NULL)
1606 node_info=node_info->child[id];
1609 Find closest color among siblings and their children.
1612 cube.distance=(double) (4.0*(QuantumRange+1.0)*(QuantumRange+
1614 ClosestColor(image,&cube,node_info->parent);
1615 cube.cache[i]=(ssize_t) cube.color_number;
1618 Assign pixel to closest colormap entry.
1620 index=(size_t) cube.cache[i];
1621 if (image->storage_class == PseudoClass)
1622 SetPixelIndex(image,(Quantum) index,q);
1623 if (cube.quantize_info->measure_error == MagickFalse)
1625 SetPixelRed(image,ClampToQuantum(image->colormap[index].red),q);
1626 SetPixelGreen(image,ClampToQuantum(image->colormap[index].green),q);
1627 SetPixelBlue(image,ClampToQuantum(image->colormap[index].blue),q);
1628 if (cube.associate_alpha != MagickFalse)
1629 SetPixelAlpha(image,ClampToQuantum(image->colormap[index].alpha),q);
1631 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1636 AssociateAlphaPixelInfo(image,&cube,image->colormap+index,&color);
1637 current[u].red=pixel.red-color.red;
1638 current[u].green=pixel.green-color.green;
1639 current[u].blue=pixel.blue-color.blue;
1640 if (cube.associate_alpha != MagickFalse)
1641 current[u].alpha=pixel.alpha-color.alpha;
1642 if (image->progress_monitor != (MagickProgressMonitor) NULL)
1647 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1648 #pragma omp critical (MagickCore_FloydSteinbergDither)
1650 proceed=SetImageProgress(image,DitherImageTag,(MagickOffsetType) y,
1652 if (proceed == MagickFalse)
1655 q+=((y+1) & 0x01)*GetPixelChannels(image);
1658 image_view=DestroyCacheView(image_view);
1659 pixels=DestroyPixelThreadSet(pixels);
1663 static MagickBooleanType
1664 RiemersmaDither(Image *,CacheView *,CubeInfo *,const unsigned int,
1665 ExceptionInfo *exception);
1667 static void Riemersma(Image *image,CacheView *image_view,CubeInfo *cube_info,
1668 const size_t level,const unsigned int direction,ExceptionInfo *exception)
1675 (void) RiemersmaDither(image,image_view,cube_info,EastGravity,
1677 (void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
1679 (void) RiemersmaDither(image,image_view,cube_info,WestGravity,
1685 (void) RiemersmaDither(image,image_view,cube_info,WestGravity,
1687 (void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
1689 (void) RiemersmaDither(image,image_view,cube_info,EastGravity,
1695 (void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
1697 (void) RiemersmaDither(image,image_view,cube_info,EastGravity,
1699 (void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
1705 (void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
1707 (void) RiemersmaDither(image,image_view,cube_info,WestGravity,
1709 (void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
1721 Riemersma(image,image_view,cube_info,level-1,NorthGravity,
1723 (void) RiemersmaDither(image,image_view,cube_info,EastGravity,
1725 Riemersma(image,image_view,cube_info,level-1,WestGravity,
1727 (void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
1729 Riemersma(image,image_view,cube_info,level-1,WestGravity,
1731 (void) RiemersmaDither(image,image_view,cube_info,WestGravity,
1733 Riemersma(image,image_view,cube_info,level-1,SouthGravity,
1739 Riemersma(image,image_view,cube_info,level-1,SouthGravity,
1741 (void) RiemersmaDither(image,image_view,cube_info,WestGravity,
1743 Riemersma(image,image_view,cube_info,level-1,EastGravity,
1745 (void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
1747 Riemersma(image,image_view,cube_info,level-1,EastGravity,
1749 (void) RiemersmaDither(image,image_view,cube_info,EastGravity,
1751 Riemersma(image,image_view,cube_info,level-1,NorthGravity,
1757 Riemersma(image,image_view,cube_info,level-1,WestGravity,
1759 (void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
1761 Riemersma(image,image_view,cube_info,level-1,NorthGravity,
1763 (void) RiemersmaDither(image,image_view,cube_info,EastGravity,
1765 Riemersma(image,image_view,cube_info,level-1,NorthGravity,
1767 (void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
1769 Riemersma(image,image_view,cube_info,level-1,EastGravity,
1775 Riemersma(image,image_view,cube_info,level-1,EastGravity,
1777 (void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
1779 Riemersma(image,image_view,cube_info,level-1,SouthGravity,
1781 (void) RiemersmaDither(image,image_view,cube_info,WestGravity,
1783 Riemersma(image,image_view,cube_info,level-1,SouthGravity,
1785 (void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
1787 Riemersma(image,image_view,cube_info,level-1,WestGravity,
1796 static MagickBooleanType RiemersmaDither(Image *image,CacheView *image_view,
1797 CubeInfo *cube_info,const unsigned int direction,ExceptionInfo *exception)
1799 #define DitherImageTag "Dither/Image"
1815 if ((p->x >= 0) && (p->x < (ssize_t) image->columns) &&
1816 (p->y >= 0) && (p->y < (ssize_t) image->rows))
1827 q=GetCacheViewAuthenticPixels(image_view,p->x,p->y,1,1,exception);
1828 if (q == (Quantum *) NULL)
1829 return(MagickFalse);
1830 AssociateAlphaPixel(image,cube_info,q,&pixel);
1831 for (i=0; i < ErrorQueueLength; i++)
1833 pixel.red+=p->weights[i]*p->error[i].red;
1834 pixel.green+=p->weights[i]*p->error[i].green;
1835 pixel.blue+=p->weights[i]*p->error[i].blue;
1836 if (cube_info->associate_alpha != MagickFalse)
1837 pixel.alpha+=p->weights[i]*p->error[i].alpha;
1839 pixel.red=(double) ClampToUnsignedQuantum(pixel.red);
1840 pixel.green=(double) ClampToUnsignedQuantum(pixel.green);
1841 pixel.blue=(double) ClampToUnsignedQuantum(pixel.blue);
1842 if (cube_info->associate_alpha != MagickFalse)
1843 pixel.alpha=(double) ClampToUnsignedQuantum(pixel.alpha);
1844 i=CacheOffset(cube_info,&pixel);
1845 if (p->cache[i] < 0)
1854 Identify the deepest node containing the pixel's color.
1857 for (index=MaxTreeDepth-1; (ssize_t) index > 0; index--)
1859 id=ColorToNodeId(cube_info,&pixel,index);
1860 if (node_info->child[id] == (NodeInfo *) NULL)
1862 node_info=node_info->child[id];
1864 node_info=node_info->parent;
1866 Find closest color among siblings and their children.
1869 p->distance=(double) (4.0*(QuantumRange+1.0)*((double)
1870 QuantumRange+1.0)+1.0);
1871 ClosestColor(image,p,node_info->parent);
1872 p->cache[i]=(ssize_t) p->color_number;
1875 Assign pixel to closest colormap entry.
1877 index=(size_t) p->cache[i];
1878 if (image->storage_class == PseudoClass)
1879 SetPixelIndex(image,(Quantum) index,q);
1880 if (cube_info->quantize_info->measure_error == MagickFalse)
1882 SetPixelRed(image,ClampToQuantum(image->colormap[index].red),q);
1883 SetPixelGreen(image,ClampToQuantum(image->colormap[index].green),q);
1884 SetPixelBlue(image,ClampToQuantum(image->colormap[index].blue),q);
1885 if (cube_info->associate_alpha != MagickFalse)
1886 SetPixelAlpha(image,ClampToQuantum(image->colormap[index].alpha),q);
1888 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1889 return(MagickFalse);
1891 Propagate the error as the last entry of the error queue.
1893 (void) CopyMagickMemory(p->error,p->error+1,(ErrorQueueLength-1)*
1894 sizeof(p->error[0]));
1895 AssociateAlphaPixelInfo(image,cube_info,image->colormap+index,&color);
1896 p->error[ErrorQueueLength-1].red=pixel.red-color.red;
1897 p->error[ErrorQueueLength-1].green=pixel.green-color.green;
1898 p->error[ErrorQueueLength-1].blue=pixel.blue-color.blue;
1899 if (cube_info->associate_alpha != MagickFalse)
1900 p->error[ErrorQueueLength-1].alpha=pixel.alpha-color.alpha;
1901 proceed=SetImageProgress(image,DitherImageTag,p->offset,p->span);
1902 if (proceed == MagickFalse)
1903 return(MagickFalse);
1908 case WestGravity: p->x--; break;
1909 case EastGravity: p->x++; break;
1910 case NorthGravity: p->y--; break;
1911 case SouthGravity: p->y++; break;
1916 static inline ssize_t MagickMax(const ssize_t x,const ssize_t y)
1923 static inline ssize_t MagickMin(const ssize_t x,const ssize_t y)
1930 static MagickBooleanType DitherImage(Image *image,CubeInfo *cube_info,
1931 ExceptionInfo *exception)
1945 if (cube_info->quantize_info->dither_method != RiemersmaDitherMethod)
1946 return(FloydSteinbergDither(image,cube_info,exception));
1948 Distribute quantization error along a Hilbert curve.
1950 (void) ResetMagickMemory(cube_info->error,0,ErrorQueueLength*
1951 sizeof(*cube_info->error));
1954 i=MagickMax((ssize_t) image->columns,(ssize_t) image->rows);
1955 for (depth=1; i != 0; depth++)
1957 if ((ssize_t) (1L << depth) < MagickMax((ssize_t) image->columns,(ssize_t) image->rows))
1959 cube_info->offset=0;
1960 cube_info->span=(MagickSizeType) image->columns*image->rows;
1961 image_view=AcquireAuthenticCacheView(image,exception);
1963 Riemersma(image,image_view,cube_info,depth-1,NorthGravity,exception);
1964 status=RiemersmaDither(image,image_view,cube_info,ForgetGravity,exception);
1965 image_view=DestroyCacheView(image_view);
1970 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1974 + G e t C u b e I n f o %
1978 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1980 % GetCubeInfo() initialize the Cube data structure.
1982 % The format of the GetCubeInfo method is:
1984 % CubeInfo GetCubeInfo(const QuantizeInfo *quantize_info,
1985 % const size_t depth,const size_t maximum_colors)
1987 % A description of each parameter follows.
1989 % o quantize_info: Specifies a pointer to an QuantizeInfo structure.
1991 % o depth: Normally, this integer value is zero or one. A zero or
1992 % one tells Quantize to choose a optimal tree depth of Log4(number_colors).
1993 % A tree of this depth generally allows the best representation of the
1994 % reference image with the least amount of memory and the fastest
1995 % computational speed. In some cases, such as an image with low color
1996 % dispersion (a few number of colors), a value other than
1997 % Log4(number_colors) is required. To expand the color tree completely,
2000 % o maximum_colors: maximum colors.
2003 static CubeInfo *GetCubeInfo(const QuantizeInfo *quantize_info,
2004 const size_t depth,const size_t maximum_colors)
2020 Initialize tree to describe color cube_info.
2022 cube_info=(CubeInfo *) AcquireMagickMemory(sizeof(*cube_info));
2023 if (cube_info == (CubeInfo *) NULL)
2024 return((CubeInfo *) NULL);
2025 (void) ResetMagickMemory(cube_info,0,sizeof(*cube_info));
2026 cube_info->depth=depth;
2027 if (cube_info->depth > MaxTreeDepth)
2028 cube_info->depth=MaxTreeDepth;
2029 if (cube_info->depth < 2)
2031 cube_info->maximum_colors=maximum_colors;
2033 Initialize root node.
2035 cube_info->root=GetNodeInfo(cube_info,0,0,(NodeInfo *) NULL);
2036 if (cube_info->root == (NodeInfo *) NULL)
2037 return((CubeInfo *) NULL);
2038 cube_info->root->parent=cube_info->root;
2039 cube_info->quantize_info=CloneQuantizeInfo(quantize_info);
2040 if (cube_info->quantize_info->dither_method == NoDitherMethod)
2043 Initialize dither resources.
2045 length=(size_t) (1UL << (4*(8-CacheShift)));
2046 cube_info->cache=(ssize_t *) AcquireQuantumMemory(length,
2047 sizeof(*cube_info->cache));
2048 if (cube_info->cache == (ssize_t *) NULL)
2049 return((CubeInfo *) NULL);
2051 Initialize color cache.
2053 for (i=0; i < (ssize_t) length; i++)
2054 cube_info->cache[i]=(-1);
2056 Distribute weights along a curve of exponential decay.
2059 for (i=0; i < ErrorQueueLength; i++)
2061 cube_info->weights[ErrorQueueLength-i-1]=MagickEpsilonReciprocal(weight);
2062 weight*=exp(log(((double) QuantumRange+1.0))/(ErrorQueueLength-1.0));
2065 Normalize the weighting factors.
2068 for (i=0; i < ErrorQueueLength; i++)
2069 weight+=cube_info->weights[i];
2071 for (i=0; i < ErrorQueueLength; i++)
2073 cube_info->weights[i]/=weight;
2074 sum+=cube_info->weights[i];
2076 cube_info->weights[0]+=1.0-sum;
2081 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2085 + G e t N o d e I n f o %
2089 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2091 % GetNodeInfo() allocates memory for a new node in the color cube tree and
2092 % presets all fields to zero.
2094 % The format of the GetNodeInfo method is:
2096 % NodeInfo *GetNodeInfo(CubeInfo *cube_info,const size_t id,
2097 % const size_t level,NodeInfo *parent)
2099 % A description of each parameter follows.
2101 % o node: The GetNodeInfo method returns a pointer to a queue of nodes.
2103 % o id: Specifies the child number of the node.
2105 % o level: Specifies the level in the storage_class the node resides.
2108 static NodeInfo *GetNodeInfo(CubeInfo *cube_info,const size_t id,
2109 const size_t level,NodeInfo *parent)
2114 if (cube_info->free_nodes == 0)
2120 Allocate a new queue of nodes.
2122 nodes=(Nodes *) AcquireMagickMemory(sizeof(*nodes));
2123 if (nodes == (Nodes *) NULL)
2124 return((NodeInfo *) NULL);
2125 nodes->nodes=(NodeInfo *) AcquireQuantumMemory(NodesInAList,
2126 sizeof(*nodes->nodes));
2127 if (nodes->nodes == (NodeInfo *) NULL)
2128 return((NodeInfo *) NULL);
2129 nodes->next=cube_info->node_queue;
2130 cube_info->node_queue=nodes;
2131 cube_info->next_node=nodes->nodes;
2132 cube_info->free_nodes=NodesInAList;
2135 cube_info->free_nodes--;
2136 node_info=cube_info->next_node++;
2137 (void) ResetMagickMemory(node_info,0,sizeof(*node_info));
2138 node_info->parent=parent;
2140 node_info->level=level;
2145 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2149 % G e t I m a g e Q u a n t i z e E r r o r %
2153 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2155 % GetImageQuantizeError() measures the difference between the original
2156 % and quantized images. This difference is the total quantization error.
2157 % The error is computed by summing over all pixels in an image the distance
2158 % squared in RGB space between each reference pixel value and its quantized
2159 % value. These values are computed:
2161 % o mean_error_per_pixel: This value is the mean error for any single
2162 % pixel in the image.
2164 % o normalized_mean_square_error: This value is the normalized mean
2165 % quantization error for any single pixel in the image. This distance
2166 % measure is normalized to a range between 0 and 1. It is independent
2167 % of the range of red, green, and blue values in the image.
2169 % o normalized_maximum_square_error: Thsi value is the normalized
2170 % maximum quantization error for any single pixel in the image. This
2171 % distance measure is normalized to a range between 0 and 1. It is
2172 % independent of the range of red, green, and blue values in your image.
2174 % The format of the GetImageQuantizeError method is:
2176 % MagickBooleanType GetImageQuantizeError(Image *image,
2177 % ExceptionInfo *exception)
2179 % A description of each parameter follows.
2181 % o image: the image.
2183 % o exception: return any errors or warnings in this structure.
2186 MagickExport MagickBooleanType GetImageQuantizeError(Image *image,
2187 ExceptionInfo *exception)
2199 mean_error_per_pixel;
2207 assert(image != (Image *) NULL);
2208 assert(image->signature == MagickSignature);
2209 if (image->debug != MagickFalse)
2210 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
2211 image->total_colors=GetNumberColors(image,(FILE *) NULL,exception);
2212 (void) ResetMagickMemory(&image->error,0,sizeof(image->error));
2213 if (image->storage_class == DirectClass)
2217 area=3.0*image->columns*image->rows;
2219 mean_error_per_pixel=0.0;
2221 image_view=AcquireVirtualCacheView(image,exception);
2222 for (y=0; y < (ssize_t) image->rows; y++)
2224 register const Quantum
2230 p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
2231 if (p == (const Quantum *) NULL)
2233 for (x=0; x < (ssize_t) image->columns; x++)
2235 index=1UL*GetPixelIndex(image,p);
2236 if (image->matte != MagickFalse)
2238 alpha=(double) (QuantumScale*GetPixelAlpha(image,p));
2239 beta=(double) (QuantumScale*image->colormap[index].alpha);
2241 distance=fabs(alpha*GetPixelRed(image,p)-beta*
2242 image->colormap[index].red);
2243 mean_error_per_pixel+=distance;
2244 mean_error+=distance*distance;
2245 if (distance > maximum_error)
2246 maximum_error=distance;
2247 distance=fabs(alpha*GetPixelGreen(image,p)-beta*
2248 image->colormap[index].green);
2249 mean_error_per_pixel+=distance;
2250 mean_error+=distance*distance;
2251 if (distance > maximum_error)
2252 maximum_error=distance;
2253 distance=fabs(alpha*GetPixelBlue(image,p)-beta*
2254 image->colormap[index].blue);
2255 mean_error_per_pixel+=distance;
2256 mean_error+=distance*distance;
2257 if (distance > maximum_error)
2258 maximum_error=distance;
2259 p+=GetPixelChannels(image);
2262 image_view=DestroyCacheView(image_view);
2263 image->error.mean_error_per_pixel=(double) mean_error_per_pixel/area;
2264 image->error.normalized_mean_error=(double) QuantumScale*QuantumScale*
2266 image->error.normalized_maximum_error=(double) QuantumScale*maximum_error;
2271 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2275 % G e t Q u a n t i z e I n f o %
2279 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2281 % GetQuantizeInfo() initializes the QuantizeInfo structure.
2283 % The format of the GetQuantizeInfo method is:
2285 % GetQuantizeInfo(QuantizeInfo *quantize_info)
2287 % A description of each parameter follows:
2289 % o quantize_info: Specifies a pointer to a QuantizeInfo structure.
2292 MagickExport void GetQuantizeInfo(QuantizeInfo *quantize_info)
2294 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"...");
2295 assert(quantize_info != (QuantizeInfo *) NULL);
2296 (void) ResetMagickMemory(quantize_info,0,sizeof(*quantize_info));
2297 quantize_info->number_colors=256;
2298 quantize_info->dither_method=RiemersmaDitherMethod;
2299 quantize_info->colorspace=UndefinedColorspace;
2300 quantize_info->measure_error=MagickFalse;
2301 quantize_info->signature=MagickSignature;
2305 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2309 % P o s t e r i z e I m a g e %
2313 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2315 % PosterizeImage() reduces the image to a limited number of colors for a
2318 % The format of the PosterizeImage method is:
2320 % MagickBooleanType PosterizeImage(Image *image,const size_t levels,
2321 % const DitherMethod dither_method,ExceptionInfo *exception)
2323 % A description of each parameter follows:
2325 % o image: Specifies a pointer to an Image structure.
2327 % o levels: Number of color levels allowed in each channel. Very low values
2328 % (2, 3, or 4) have the most visible effect.
2330 % o dither_method: choose from UndefinedDitherMethod, NoDitherMethod,
2331 % RiemersmaDitherMethod, FloydSteinbergDitherMethod.
2333 % o exception: return any errors or warnings in this structure.
2337 static inline ssize_t MagickRound(double x)
2340 Round the fraction to nearest integer.
2343 return((ssize_t) (x+0.5));
2344 return((ssize_t) (x-0.5));
2347 MagickExport MagickBooleanType PosterizeImage(Image *image,const size_t levels,
2348 const DitherMethod dither_method,ExceptionInfo *exception)
2350 #define PosterizeImageTag "Posterize/Image"
2351 #define PosterizePixel(pixel) (Quantum) (QuantumRange*(MagickRound( \
2352 QuantumScale*pixel*(levels-1)))/MagickMax((ssize_t) levels-1,1))
2372 assert(image != (Image *) NULL);
2373 assert(image->signature == MagickSignature);
2374 if (image->debug != MagickFalse)
2375 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
2376 if (image->storage_class == PseudoClass)
2377 #if defined(MAGICKCORE_OPENMP_SUPPORT)
2378 #pragma omp parallel for schedule(static,4) shared(progress,status) \
2379 dynamic_number_threads(image,image->columns,1,1)
2381 for (i=0; i < (ssize_t) image->colors; i++)
2386 if ((GetPixelRedTraits(image) & UpdatePixelTrait) != 0)
2387 image->colormap[i].red=(double)
2388 PosterizePixel(image->colormap[i].red);
2389 if ((GetPixelGreenTraits(image) & UpdatePixelTrait) != 0)
2390 image->colormap[i].green=(double)
2391 PosterizePixel(image->colormap[i].green);
2392 if ((GetPixelBlueTraits(image) & UpdatePixelTrait) != 0)
2393 image->colormap[i].blue=(double)
2394 PosterizePixel(image->colormap[i].blue);
2395 if ((GetPixelAlphaTraits(image) & UpdatePixelTrait) != 0)
2396 image->colormap[i].alpha=(double)
2397 PosterizePixel(image->colormap[i].alpha);
2404 image_view=AcquireAuthenticCacheView(image,exception);
2405 #if defined(MAGICKCORE_OPENMP_SUPPORT)
2406 #pragma omp parallel for schedule(static,4) shared(progress,status) \
2407 dynamic_number_threads(image,image->columns,image->rows,1)
2409 for (y=0; y < (ssize_t) image->rows; y++)
2417 if (status == MagickFalse)
2419 q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
2420 if (q == (Quantum *) NULL)
2425 for (x=0; x < (ssize_t) image->columns; x++)
2427 if ((GetPixelRedTraits(image) & UpdatePixelTrait) != 0)
2428 SetPixelRed(image,PosterizePixel(GetPixelRed(image,q)),q);
2429 if ((GetPixelGreenTraits(image) & UpdatePixelTrait) != 0)
2430 SetPixelGreen(image,PosterizePixel(GetPixelGreen(image,q)),q);
2431 if ((GetPixelBlueTraits(image) & UpdatePixelTrait) != 0)
2432 SetPixelBlue(image,PosterizePixel(GetPixelBlue(image,q)),q);
2433 if (((GetPixelBlackTraits(image) & UpdatePixelTrait) != 0) &&
2434 (image->colorspace == CMYKColorspace))
2435 SetPixelBlack(image,PosterizePixel(GetPixelBlack(image,q)),q);
2436 if (((GetPixelAlphaTraits(image) & UpdatePixelTrait) != 0) &&
2437 (image->matte == MagickTrue))
2438 SetPixelAlpha(image,PosterizePixel(GetPixelAlpha(image,q)),q);
2439 q+=GetPixelChannels(image);
2441 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
2443 if (image->progress_monitor != (MagickProgressMonitor) NULL)
2448 #if defined(MAGICKCORE_OPENMP_SUPPORT)
2449 #pragma omp critical (MagickCore_PosterizeImage)
2451 proceed=SetImageProgress(image,PosterizeImageTag,progress++,
2453 if (proceed == MagickFalse)
2457 image_view=DestroyCacheView(image_view);
2458 quantize_info=AcquireQuantizeInfo((ImageInfo *) NULL);
2459 quantize_info->number_colors=(size_t) MagickMin((ssize_t) levels*levels*
2460 levels,MaxColormapSize+1);
2461 quantize_info->dither_method=dither_method;
2462 quantize_info->tree_depth=MaxTreeDepth;
2463 status=QuantizeImage(quantize_info,image,exception);
2464 quantize_info=DestroyQuantizeInfo(quantize_info);
2469 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2473 + P r u n e C h i l d %
2477 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2479 % PruneChild() deletes the given node and merges its statistics into its
2482 % The format of the PruneSubtree method is:
2484 % PruneChild(const Image *image,CubeInfo *cube_info,
2485 % const NodeInfo *node_info)
2487 % A description of each parameter follows.
2489 % o image: the image.
2491 % o cube_info: A pointer to the Cube structure.
2493 % o node_info: pointer to node in color cube tree that is to be pruned.
2496 static void PruneChild(const Image *image,CubeInfo *cube_info,
2497 const NodeInfo *node_info)
2509 Traverse any children.
2511 number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2512 for (i=0; i < (ssize_t) number_children; i++)
2513 if (node_info->child[i] != (NodeInfo *) NULL)
2514 PruneChild(image,cube_info,node_info->child[i]);
2516 Merge color statistics into parent.
2518 parent=node_info->parent;
2519 parent->number_unique+=node_info->number_unique;
2520 parent->total_color.red+=node_info->total_color.red;
2521 parent->total_color.green+=node_info->total_color.green;
2522 parent->total_color.blue+=node_info->total_color.blue;
2523 parent->total_color.alpha+=node_info->total_color.alpha;
2524 parent->child[node_info->id]=(NodeInfo *) NULL;
2529 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2533 + P r u n e L e v e l %
2537 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2539 % PruneLevel() deletes all nodes at the bottom level of the color tree merging
2540 % their color statistics into their parent node.
2542 % The format of the PruneLevel method is:
2544 % PruneLevel(const Image *image,CubeInfo *cube_info,
2545 % const NodeInfo *node_info)
2547 % A description of each parameter follows.
2549 % o image: the image.
2551 % o cube_info: A pointer to the Cube structure.
2553 % o node_info: pointer to node in color cube tree that is to be pruned.
2556 static void PruneLevel(const Image *image,CubeInfo *cube_info,
2557 const NodeInfo *node_info)
2566 Traverse any children.
2568 number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2569 for (i=0; i < (ssize_t) number_children; i++)
2570 if (node_info->child[i] != (NodeInfo *) NULL)
2571 PruneLevel(image,cube_info,node_info->child[i]);
2572 if (node_info->level == cube_info->depth)
2573 PruneChild(image,cube_info,node_info);
2577 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2581 + P r u n e T o C u b e D e p t h %
2585 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2587 % PruneToCubeDepth() deletes any nodes at a depth greater than
2588 % cube_info->depth while merging their color statistics into their parent
2591 % The format of the PruneToCubeDepth method is:
2593 % PruneToCubeDepth(const Image *image,CubeInfo *cube_info,
2594 % const NodeInfo *node_info)
2596 % A description of each parameter follows.
2598 % o cube_info: A pointer to the Cube structure.
2600 % o node_info: pointer to node in color cube tree that is to be pruned.
2603 static void PruneToCubeDepth(const Image *image,CubeInfo *cube_info,
2604 const NodeInfo *node_info)
2613 Traverse any children.
2615 number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2616 for (i=0; i < (ssize_t) number_children; i++)
2617 if (node_info->child[i] != (NodeInfo *) NULL)
2618 PruneToCubeDepth(image,cube_info,node_info->child[i]);
2619 if (node_info->level > cube_info->depth)
2620 PruneChild(image,cube_info,node_info);
2624 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2628 % Q u a n t i z e I m a g e %
2632 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2634 % QuantizeImage() analyzes the colors within a reference image and chooses a
2635 % fixed number of colors to represent the image. The goal of the algorithm
2636 % is to minimize the color difference between the input and output image while
2637 % minimizing the processing time.
2639 % The format of the QuantizeImage method is:
2641 % MagickBooleanType QuantizeImage(const QuantizeInfo *quantize_info,
2642 % Image *image,ExceptionInfo *exception)
2644 % A description of each parameter follows:
2646 % o quantize_info: Specifies a pointer to an QuantizeInfo structure.
2648 % o image: the image.
2650 % o exception: return any errors or warnings in this structure.
2654 static MagickBooleanType DirectToColormapImage(Image *image,
2655 ExceptionInfo *exception)
2673 number_colors=(size_t) (image->columns*image->rows);
2674 if (AcquireImageColormap(image,number_colors,exception) == MagickFalse)
2675 ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
2677 if (image->colors != number_colors)
2678 return(MagickFalse);
2680 image_view=AcquireAuthenticCacheView(image,exception);
2681 for (y=0; y < (ssize_t) image->rows; y++)
2692 q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
2693 if (q == (Quantum *) NULL)
2695 for (x=0; x < (ssize_t) image->columns; x++)
2697 image->colormap[i].red=(double) GetPixelRed(image,q);
2698 image->colormap[i].green=(double) GetPixelGreen(image,q);
2699 image->colormap[i].blue=(double) GetPixelBlue(image,q);
2700 image->colormap[i].alpha=(double) GetPixelAlpha(image,q);
2701 SetPixelIndex(image,(Quantum) i,q);
2703 q+=GetPixelChannels(image);
2705 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
2707 proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) y,
2709 if (proceed == MagickFalse)
2712 image_view=DestroyCacheView(image_view);
2716 MagickExport MagickBooleanType QuantizeImage(const QuantizeInfo *quantize_info,
2717 Image *image,ExceptionInfo *exception)
2729 assert(quantize_info != (const QuantizeInfo *) NULL);
2730 assert(quantize_info->signature == MagickSignature);
2731 assert(image != (Image *) NULL);
2732 assert(image->signature == MagickSignature);
2733 if (image->debug != MagickFalse)
2734 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
2735 maximum_colors=quantize_info->number_colors;
2736 if (maximum_colors == 0)
2737 maximum_colors=MaxColormapSize;
2738 if (maximum_colors > MaxColormapSize)
2739 maximum_colors=MaxColormapSize;
2740 if (image->matte == MagickFalse)
2742 if ((image->columns*image->rows) <= maximum_colors)
2743 (void) DirectToColormapImage(image,exception);
2744 if (IsImageGray(image,exception) != MagickFalse)
2745 (void) SetGrayscaleImage(image,exception);
2747 if ((image->storage_class == PseudoClass) &&
2748 (image->colors <= maximum_colors))
2750 depth=quantize_info->tree_depth;
2757 Depth of color tree is: Log4(colormap size)+2.
2759 colors=maximum_colors;
2760 for (depth=1; colors != 0; depth++)
2762 if ((quantize_info->dither_method != NoDitherMethod) && (depth > 2))
2764 if ((image->matte != MagickFalse) && (depth > 5))
2768 Initialize color cube.
2770 cube_info=GetCubeInfo(quantize_info,depth,maximum_colors);
2771 if (cube_info == (CubeInfo *) NULL)
2772 ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
2774 status=ClassifyImageColors(cube_info,image,exception);
2775 if (status != MagickFalse)
2778 Reduce the number of colors in the image.
2780 ReduceImageColors(image,cube_info);
2781 status=AssignImageColors(image,cube_info,exception);
2783 DestroyCubeInfo(cube_info);
2788 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2792 % Q u a n t i z e I m a g e s %
2796 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2798 % QuantizeImages() analyzes the colors within a set of reference images and
2799 % chooses a fixed number of colors to represent the set. The goal of the
2800 % algorithm is to minimize the color difference between the input and output
2801 % images while minimizing the processing time.
2803 % The format of the QuantizeImages method is:
2805 % MagickBooleanType QuantizeImages(const QuantizeInfo *quantize_info,
2806 % Image *images,ExceptionInfo *exception)
2808 % A description of each parameter follows:
2810 % o quantize_info: Specifies a pointer to an QuantizeInfo structure.
2812 % o images: Specifies a pointer to a list of Image structures.
2814 % o exception: return any errors or warnings in this structure.
2817 MagickExport MagickBooleanType QuantizeImages(const QuantizeInfo *quantize_info,
2818 Image *images,ExceptionInfo *exception)
2830 MagickProgressMonitor
2841 assert(quantize_info != (const QuantizeInfo *) NULL);
2842 assert(quantize_info->signature == MagickSignature);
2843 assert(images != (Image *) NULL);
2844 assert(images->signature == MagickSignature);
2845 if (images->debug != MagickFalse)
2846 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",images->filename);
2847 if (GetNextImageInList(images) == (Image *) NULL)
2850 Handle a single image with QuantizeImage.
2852 status=QuantizeImage(quantize_info,images,exception);
2856 maximum_colors=quantize_info->number_colors;
2857 if (maximum_colors == 0)
2858 maximum_colors=MaxColormapSize;
2859 if (maximum_colors > MaxColormapSize)
2860 maximum_colors=MaxColormapSize;
2861 depth=quantize_info->tree_depth;
2868 Depth of color tree is: Log4(colormap size)+2.
2870 colors=maximum_colors;
2871 for (depth=1; colors != 0; depth++)
2873 if (quantize_info->dither_method != NoDitherMethod)
2877 Initialize color cube.
2879 cube_info=GetCubeInfo(quantize_info,depth,maximum_colors);
2880 if (cube_info == (CubeInfo *) NULL)
2882 (void) ThrowMagickException(exception,GetMagickModule(),
2883 ResourceLimitError,"MemoryAllocationFailed","'%s'",images->filename);
2884 return(MagickFalse);
2886 number_images=GetImageListLength(images);
2888 for (i=0; image != (Image *) NULL; i++)
2890 progress_monitor=SetImageProgressMonitor(image,(MagickProgressMonitor) NULL,
2891 image->client_data);
2892 status=ClassifyImageColors(cube_info,image,exception);
2893 if (status == MagickFalse)
2895 (void) SetImageProgressMonitor(image,progress_monitor,image->client_data);
2896 proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) i,
2898 if (proceed == MagickFalse)
2900 image=GetNextImageInList(image);
2902 if (status != MagickFalse)
2905 Reduce the number of colors in an image sequence.
2907 ReduceImageColors(images,cube_info);
2909 for (i=0; image != (Image *) NULL; i++)
2911 progress_monitor=SetImageProgressMonitor(image,(MagickProgressMonitor)
2912 NULL,image->client_data);
2913 status=AssignImageColors(image,cube_info,exception);
2914 if (status == MagickFalse)
2916 (void) SetImageProgressMonitor(image,progress_monitor,
2917 image->client_data);
2918 proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) i,
2920 if (proceed == MagickFalse)
2922 image=GetNextImageInList(image);
2925 DestroyCubeInfo(cube_info);
2930 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2938 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2940 % Reduce() traverses the color cube tree and prunes any node whose
2941 % quantization error falls below a particular threshold.
2943 % The format of the Reduce method is:
2945 % Reduce(const Image *image,CubeInfo *cube_info,const NodeInfo *node_info)
2947 % A description of each parameter follows.
2949 % o image: the image.
2951 % o cube_info: A pointer to the Cube structure.
2953 % o node_info: pointer to node in color cube tree that is to be pruned.
2956 static void Reduce(const Image *image,CubeInfo *cube_info,
2957 const NodeInfo *node_info)
2966 Traverse any children.
2968 number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2969 for (i=0; i < (ssize_t) number_children; i++)
2970 if (node_info->child[i] != (NodeInfo *) NULL)
2971 Reduce(image,cube_info,node_info->child[i]);
2972 if (node_info->quantize_error <= cube_info->pruning_threshold)
2973 PruneChild(image,cube_info,node_info);
2977 Find minimum pruning threshold.
2979 if (node_info->number_unique > 0)
2980 cube_info->colors++;
2981 if (node_info->quantize_error < cube_info->next_threshold)
2982 cube_info->next_threshold=node_info->quantize_error;
2987 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2991 + R e d u c e I m a g e C o l o r s %
2995 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2997 % ReduceImageColors() repeatedly prunes the tree until the number of nodes
2998 % with n2 > 0 is less than or equal to the maximum number of colors allowed
2999 % in the output image. On any given iteration over the tree, it selects
3000 % those nodes whose E value is minimal for pruning and merges their
3001 % color statistics upward. It uses a pruning threshold, Ep, to govern
3002 % node selection as follows:
3005 % while number of nodes with (n2 > 0) > required maximum number of colors
3006 % prune all nodes such that E <= Ep
3007 % Set Ep to minimum E in remaining nodes
3009 % This has the effect of minimizing any quantization error when merging
3010 % two nodes together.
3012 % When a node to be pruned has offspring, the pruning procedure invokes
3013 % itself recursively in order to prune the tree from the leaves upward.
3014 % n2, Sr, Sg, and Sb in a node being pruned are always added to the
3015 % corresponding data in that node's parent. This retains the pruned
3016 % node's color characteristics for later averaging.
3018 % For each node, n2 pixels exist for which that node represents the
3019 % smallest volume in RGB space containing those pixel's colors. When n2
3020 % > 0 the node will uniquely define a color in the output image. At the
3021 % beginning of reduction, n2 = 0 for all nodes except a the leaves of
3022 % the tree which represent colors present in the input image.
3024 % The other pixel count, n1, indicates the total number of colors
3025 % within the cubic volume which the node represents. This includes n1 -
3026 % n2 pixels whose colors should be defined by nodes at a lower level in
3029 % The format of the ReduceImageColors method is:
3031 % ReduceImageColors(const Image *image,CubeInfo *cube_info)
3033 % A description of each parameter follows.
3035 % o image: the image.
3037 % o cube_info: A pointer to the Cube structure.
3040 static void ReduceImageColors(const Image *image,CubeInfo *cube_info)
3042 #define ReduceImageTag "Reduce/Image"
3053 cube_info->next_threshold=0.0;
3054 for (span=cube_info->colors; cube_info->colors > cube_info->maximum_colors; )
3056 cube_info->pruning_threshold=cube_info->next_threshold;
3057 cube_info->next_threshold=cube_info->root->quantize_error-1;
3058 cube_info->colors=0;
3059 Reduce(image,cube_info,cube_info->root);
3060 offset=(MagickOffsetType) span-cube_info->colors;
3061 proceed=SetImageProgress(image,ReduceImageTag,offset,span-
3062 cube_info->maximum_colors+1);
3063 if (proceed == MagickFalse)
3069 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3073 % R e m a p I m a g e %
3077 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3079 % RemapImage() replaces the colors of an image with a dither of the colors
3082 % The format of the RemapImage method is:
3084 % MagickBooleanType RemapImage(const QuantizeInfo *quantize_info,
3085 % Image *image,const Image *remap_image,ExceptionInfo *exception)
3087 % A description of each parameter follows:
3089 % o quantize_info: Specifies a pointer to an QuantizeInfo structure.
3091 % o image: the image.
3093 % o remap_image: the reference image.
3095 % o exception: return any errors or warnings in this structure.
3098 MagickExport MagickBooleanType RemapImage(const QuantizeInfo *quantize_info,
3099 Image *image,const Image *remap_image,ExceptionInfo *exception)
3108 Initialize color cube.
3110 assert(image != (Image *) NULL);
3111 assert(image->signature == MagickSignature);
3112 if (image->debug != MagickFalse)
3113 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
3114 assert(remap_image != (Image *) NULL);
3115 assert(remap_image->signature == MagickSignature);
3116 cube_info=GetCubeInfo(quantize_info,MaxTreeDepth,
3117 quantize_info->number_colors);
3118 if (cube_info == (CubeInfo *) NULL)
3119 ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3121 status=ClassifyImageColors(cube_info,remap_image,exception);
3122 if (status != MagickFalse)
3125 Classify image colors from the reference image.
3127 cube_info->quantize_info->number_colors=cube_info->colors;
3128 status=AssignImageColors(image,cube_info,exception);
3130 DestroyCubeInfo(cube_info);
3135 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3139 % R e m a p I m a g e s %
3143 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3145 % RemapImages() replaces the colors of a sequence of images with the
3146 % closest color from a reference image.
3148 % The format of the RemapImage method is:
3150 % MagickBooleanType RemapImages(const QuantizeInfo *quantize_info,
3151 % Image *images,Image *remap_image,ExceptionInfo *exception)
3153 % A description of each parameter follows:
3155 % o quantize_info: Specifies a pointer to an QuantizeInfo structure.
3157 % o images: the image sequence.
3159 % o remap_image: the reference image.
3161 % o exception: return any errors or warnings in this structure.
3164 MagickExport MagickBooleanType RemapImages(const QuantizeInfo *quantize_info,
3165 Image *images,const Image *remap_image,ExceptionInfo *exception)
3176 assert(images != (Image *) NULL);
3177 assert(images->signature == MagickSignature);
3178 if (images->debug != MagickFalse)
3179 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",images->filename);
3181 if (remap_image == (Image *) NULL)
3184 Create a global colormap for an image sequence.
3186 status=QuantizeImages(quantize_info,images,exception);
3190 Classify image colors from the reference image.
3192 cube_info=GetCubeInfo(quantize_info,MaxTreeDepth,
3193 quantize_info->number_colors);
3194 if (cube_info == (CubeInfo *) NULL)
3195 ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3197 status=ClassifyImageColors(cube_info,remap_image,exception);
3198 if (status != MagickFalse)
3201 Classify image colors from the reference image.
3203 cube_info->quantize_info->number_colors=cube_info->colors;
3205 for ( ; image != (Image *) NULL; image=GetNextImageInList(image))
3207 status=AssignImageColors(image,cube_info,exception);
3208 if (status == MagickFalse)
3212 DestroyCubeInfo(cube_info);
3217 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3221 % S e t G r a y s c a l e I m a g e %
3225 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3227 % SetGrayscaleImage() converts an image to a PseudoClass grayscale image.
3229 % The format of the SetGrayscaleImage method is:
3231 % MagickBooleanType SetGrayscaleImage(Image *image,ExceptionInfo *exeption)
3233 % A description of each parameter follows:
3235 % o image: The image.
3237 % o exception: return any errors or warnings in this structure.
3241 #if defined(__cplusplus) || defined(c_plusplus)
3245 static int IntensityCompare(const void *x,const void *y)
3254 color_1=(PixelInfo *) x;
3255 color_2=(PixelInfo *) y;
3256 intensity=(ssize_t) (GetPixelInfoIntensity(color_1)-(ssize_t)
3257 GetPixelInfoIntensity(color_2));
3258 return((int) intensity);
3261 #if defined(__cplusplus) || defined(c_plusplus)
3265 static MagickBooleanType SetGrayscaleImage(Image *image,
3266 ExceptionInfo *exception)
3285 assert(image != (Image *) NULL);
3286 assert(image->signature == MagickSignature);
3287 if (image->type != GrayscaleType)
3288 (void) TransformImageColorspace(image,GRAYColorspace,exception);
3289 colormap_index=(ssize_t *) AcquireQuantumMemory(MaxMap+1,
3290 sizeof(*colormap_index));
3291 if (colormap_index == (ssize_t *) NULL)
3292 ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3294 if (image->storage_class != PseudoClass)
3296 for (i=0; i <= (ssize_t) MaxMap; i++)
3297 colormap_index[i]=(-1);
3298 if (AcquireImageColormap(image,MaxMap+1,exception) == MagickFalse)
3299 ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3303 image_view=AcquireAuthenticCacheView(image,exception);
3304 #if defined(MAGICKCORE_OPENMP_SUPPORT)
3305 #pragma omp parallel for schedule(static,4) shared(status) \
3306 dynamic_number_threads(image,image->columns,image->rows,1)
3308 for (y=0; y < (ssize_t) image->rows; y++)
3316 if (status == MagickFalse)
3318 q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,
3320 if (q == (Quantum *) NULL)
3325 for (x=0; x < (ssize_t) image->columns; x++)
3330 intensity=ScaleQuantumToMap(GetPixelRed(image,q));
3331 if (colormap_index[intensity] < 0)
3333 #if defined(MAGICKCORE_OPENMP_SUPPORT)
3334 #pragma omp critical (MagickCore_SetGrayscaleImage)
3336 if (colormap_index[intensity] < 0)
3338 colormap_index[intensity]=(ssize_t) image->colors;
3339 image->colormap[image->colors].red=(double)
3340 GetPixelRed(image,q);
3341 image->colormap[image->colors].green=(double)
3342 GetPixelGreen(image,q);
3343 image->colormap[image->colors].blue=(double)
3344 GetPixelBlue(image,q);
3348 SetPixelIndex(image,(Quantum)
3349 colormap_index[intensity],q);
3350 q+=GetPixelChannels(image);
3352 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
3355 image_view=DestroyCacheView(image_view);
3357 for (i=0; i < (ssize_t) image->colors; i++)
3358 image->colormap[i].alpha=(double) i;
3359 qsort((void *) image->colormap,image->colors,sizeof(PixelInfo),
3361 colormap=(PixelInfo *) AcquireQuantumMemory(image->colors,
3363 if (colormap == (PixelInfo *) NULL)
3364 ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3367 colormap[j]=image->colormap[0];
3368 for (i=0; i < (ssize_t) image->colors; i++)
3370 if (IsPixelInfoEquivalent(&colormap[j],&image->colormap[i]) == MagickFalse)
3373 colormap[j]=image->colormap[i];
3375 colormap_index[(ssize_t) image->colormap[i].alpha]=j;
3377 image->colors=(size_t) (j+1);
3378 image->colormap=(PixelInfo *) RelinquishMagickMemory(image->colormap);
3379 image->colormap=colormap;
3381 image_view=AcquireAuthenticCacheView(image,exception);
3382 #if defined(MAGICKCORE_OPENMP_SUPPORT)
3383 #pragma omp parallel for schedule(static,4) shared(status) \
3384 dynamic_number_threads(image,image->columns,image->rows,1)
3386 for (y=0; y < (ssize_t) image->rows; y++)
3394 if (status == MagickFalse)
3396 q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
3397 if (q == (Quantum *) NULL)
3402 for (x=0; x < (ssize_t) image->columns; x++)
3404 SetPixelIndex(image,(Quantum) colormap_index[ScaleQuantumToMap(
3405 GetPixelIndex(image,q))],q);
3406 q+=GetPixelChannels(image);
3408 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
3411 image_view=DestroyCacheView(image_view);
3412 colormap_index=(ssize_t *) RelinquishMagickMemory(colormap_index);
3413 image->type=GrayscaleType;
3414 if (IsImageMonochrome(image,exception) != MagickFalse)
3415 image->type=BilevelType;