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13 % MagickCore Methods to Reduce the Number of Unique Colors in an Image %
20 % Copyright 1999-2011 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/enhance.h"
185 #include "MagickCore/exception.h"
186 #include "MagickCore/exception-private.h"
187 #include "MagickCore/histogram.h"
188 #include "MagickCore/image.h"
189 #include "MagickCore/image-private.h"
190 #include "MagickCore/list.h"
191 #include "MagickCore/memory_.h"
192 #include "MagickCore/monitor.h"
193 #include "MagickCore/monitor-private.h"
194 #include "MagickCore/option.h"
195 #include "MagickCore/pixel-accessor.h"
196 #include "MagickCore/quantize.h"
197 #include "MagickCore/quantum.h"
198 #include "MagickCore/quantum-private.h"
199 #include "MagickCore/string_.h"
200 #include "MagickCore/thread-private.h"
205 #if !defined(__APPLE__) && !defined(TARGET_OS_IPHONE)
210 #define ErrorQueueLength 16
211 #define MaxNodes 266817
212 #define MaxTreeDepth 8
213 #define NodesInAList 1920
218 typedef struct _RealPixelPacket
227 typedef struct _NodeInfo
248 typedef struct _Nodes
257 typedef struct _CubeInfo
295 error[ErrorQueueLength];
298 weights[ErrorQueueLength];
324 *GetCubeInfo(const QuantizeInfo *,const size_t,const size_t);
327 *GetNodeInfo(CubeInfo *,const size_t,const size_t,NodeInfo *);
329 static MagickBooleanType
330 AssignImageColors(Image *,CubeInfo *),
331 ClassifyImageColors(CubeInfo *,const Image *,ExceptionInfo *),
332 DitherImage(Image *,CubeInfo *),
333 SetGrayscaleImage(Image *);
336 DefineImageColormap(Image *,CubeInfo *,NodeInfo *);
339 ClosestColor(const Image *,CubeInfo *,const NodeInfo *),
340 DestroyCubeInfo(CubeInfo *),
341 PruneLevel(const Image *,CubeInfo *,const NodeInfo *),
342 PruneToCubeDepth(const Image *,CubeInfo *,const NodeInfo *),
343 ReduceImageColors(const Image *,CubeInfo *);
346 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
350 % A c q u i r e Q u a n t i z e I n f o %
354 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
356 % AcquireQuantizeInfo() allocates the QuantizeInfo structure.
358 % The format of the AcquireQuantizeInfo method is:
360 % QuantizeInfo *AcquireQuantizeInfo(const ImageInfo *image_info)
362 % A description of each parameter follows:
364 % o image_info: the image info.
367 MagickExport QuantizeInfo *AcquireQuantizeInfo(const ImageInfo *image_info)
372 quantize_info=(QuantizeInfo *) AcquireMagickMemory(sizeof(*quantize_info));
373 if (quantize_info == (QuantizeInfo *) NULL)
374 ThrowFatalException(ResourceLimitFatalError,"MemoryAllocationFailed");
375 GetQuantizeInfo(quantize_info);
376 if (image_info != (ImageInfo *) NULL)
381 quantize_info->dither=image_info->dither;
382 option=GetImageOption(image_info,"dither");
383 if (option != (const char *) NULL)
384 quantize_info->dither_method=(DitherMethod) ParseCommandOption(
385 MagickDitherOptions,MagickFalse,option);
386 quantize_info->measure_error=image_info->verbose;
388 return(quantize_info);
392 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
396 + A s s i g n I m a g e C o l o r s %
400 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
402 % AssignImageColors() generates the output image from the pruned tree. The
403 % output image consists of two parts: (1) A color map, which is an array
404 % of color descriptions (RGB triples) for each color present in the
405 % output image; (2) A pixel array, which represents each pixel as an
406 % index into the color map array.
408 % First, the assignment phase makes one pass over the pruned color
409 % description tree to establish the image's color map. For each node
410 % with n2 > 0, it divides Sr, Sg, and Sb by n2 . This produces the mean
411 % color of all pixels that classify no lower than this node. Each of
412 % these colors becomes an entry in the color map.
414 % Finally, the assignment phase reclassifies each pixel in the pruned
415 % tree to identify the deepest node containing the pixel's color. The
416 % pixel's value in the pixel array becomes the index of this node's mean
417 % color in the color map.
419 % The format of the AssignImageColors() method is:
421 % MagickBooleanType AssignImageColors(Image *image,CubeInfo *cube_info)
423 % A description of each parameter follows.
425 % o image: the image.
427 % o cube_info: A pointer to the Cube structure.
431 static inline void AssociateAlphaPixel(const Image *image,
432 const CubeInfo *cube_info,const Quantum *pixel,
433 RealPixelPacket *alpha_pixel)
438 if ((cube_info->associate_alpha == MagickFalse) ||
439 (GetPixelAlpha(image,pixel)== OpaqueAlpha))
441 alpha_pixel->red=(MagickRealType) GetPixelRed(image,pixel);
442 alpha_pixel->green=(MagickRealType) GetPixelGreen(image,pixel);
443 alpha_pixel->blue=(MagickRealType) GetPixelBlue(image,pixel);
444 alpha_pixel->alpha=(MagickRealType) GetPixelAlpha(image,pixel);
447 alpha=(MagickRealType) (QuantumScale*GetPixelAlpha(image,pixel));
448 alpha_pixel->red=alpha*GetPixelRed(image,pixel);
449 alpha_pixel->green=alpha*GetPixelGreen(image,pixel);
450 alpha_pixel->blue=alpha*GetPixelBlue(image,pixel);
451 alpha_pixel->alpha=(MagickRealType) GetPixelAlpha(image,pixel);
454 static inline void AssociateAlphaPixelPacket(const Image *image,
455 const CubeInfo *cube_info,const PixelPacket *pixel,
456 RealPixelPacket *alpha_pixel)
461 if ((cube_info->associate_alpha == MagickFalse) ||
462 (pixel->alpha == OpaqueAlpha))
464 alpha_pixel->red=(MagickRealType) pixel->red;
465 alpha_pixel->green=(MagickRealType) pixel->green;
466 alpha_pixel->blue=(MagickRealType) pixel->blue;
467 alpha_pixel->alpha=(MagickRealType) pixel->alpha;
470 alpha=(MagickRealType) (QuantumScale*pixel->alpha);
471 alpha_pixel->red=alpha*pixel->red;
472 alpha_pixel->green=alpha*pixel->green;
473 alpha_pixel->blue=alpha*pixel->blue;
474 alpha_pixel->alpha=(MagickRealType) pixel->alpha;
477 static inline Quantum ClampToUnsignedQuantum(const MagickRealType value)
481 if (value >= QuantumRange)
482 return((Quantum) QuantumRange);
483 return((Quantum) (value+0.5));
486 static inline size_t ColorToNodeId(const CubeInfo *cube_info,
487 const RealPixelPacket *pixel,size_t index)
492 id=(size_t) (((ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->red)) >> index) & 0x01) |
493 ((ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->green)) >> index) & 0x01) << 1 |
494 ((ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->blue)) >> index) & 0x01) << 2);
495 if (cube_info->associate_alpha != MagickFalse)
496 id|=((ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->alpha)) >> index) & 0x1) << 3;
500 static MagickBooleanType AssignImageColors(Image *image,CubeInfo *cube_info)
502 #define AssignImageTag "Assign/Image"
508 Allocate image colormap.
510 if ((cube_info->quantize_info->colorspace != UndefinedColorspace) &&
511 (cube_info->quantize_info->colorspace != CMYKColorspace))
512 (void) TransformImageColorspace((Image *) image,
513 cube_info->quantize_info->colorspace);
515 if ((image->colorspace != GRAYColorspace) &&
516 (image->colorspace != RGBColorspace) &&
517 (image->colorspace != CMYColorspace))
518 (void) TransformImageColorspace((Image *) image,RGBColorspace);
519 if (AcquireImageColormap(image,cube_info->colors) == MagickFalse)
520 ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
523 cube_info->transparent_pixels=0;
524 cube_info->transparent_index=(-1);
525 (void) DefineImageColormap(image,cube_info,cube_info->root);
527 Create a reduced color image.
529 if ((cube_info->quantize_info->dither != MagickFalse) &&
530 (cube_info->quantize_info->dither_method != NoDitherMethod))
531 (void) DitherImage(image,cube_info);
544 exception=(&image->exception);
545 image_view=AcquireCacheView(image);
546 #if defined(MAGICKCORE_OPENMP_SUPPORT)
547 #pragma omp parallel for schedule(dynamic,4) shared(status)
549 for (y=0; y < (ssize_t) image->rows; y++)
563 if (status == MagickFalse)
565 q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,
567 if (q == (const Quantum *) NULL)
573 for (x=0; x < (ssize_t) image->columns; x+=count)
578 register const NodeInfo
589 Identify the deepest node containing the pixel's color.
591 for (count=1; (x+count) < (ssize_t) image->columns; count++)
596 GetPixelPacket(image,q+count*GetPixelChannels(image),&packet);
597 if (IsPixelEquivalent(image,q,&packet) == MagickFalse)
600 AssociateAlphaPixel(image,&cube,q,&pixel);
602 for (index=MaxTreeDepth-1; (ssize_t) index > 0; index--)
604 id=ColorToNodeId(&cube,&pixel,index);
605 if (node_info->child[id] == (NodeInfo *) NULL)
607 node_info=node_info->child[id];
610 Find closest color among siblings and their children.
613 cube.distance=(MagickRealType) (4.0*(QuantumRange+1.0)*
614 (QuantumRange+1.0)+1.0);
615 ClosestColor(image,&cube,node_info->parent);
616 index=cube.color_number;
617 for (i=0; i < (ssize_t) count; i++)
619 if (image->storage_class == PseudoClass)
620 SetPixelIndex(image,(Quantum) index,q);
621 if (cube.quantize_info->measure_error == MagickFalse)
623 SetPixelRed(image,image->colormap[index].red,q);
624 SetPixelGreen(image,image->colormap[index].green,q);
625 SetPixelBlue(image,image->colormap[index].blue,q);
626 if (cube.associate_alpha != MagickFalse)
627 SetPixelAlpha(image,image->colormap[index].alpha,q);
629 q+=GetPixelChannels(image);
632 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
634 if (image->progress_monitor != (MagickProgressMonitor) NULL)
639 #if defined(MAGICKCORE_OPENMP_SUPPORT)
640 #pragma omp critical (MagickCore_AssignImageColors)
642 proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) y,
644 if (proceed == MagickFalse)
648 image_view=DestroyCacheView(image_view);
650 if (cube_info->quantize_info->measure_error != MagickFalse)
651 (void) GetImageQuantizeError(image);
652 if ((cube_info->quantize_info->number_colors == 2) &&
653 (cube_info->quantize_info->colorspace == GRAYColorspace))
668 for (i=0; i < (ssize_t) image->colors; i++)
670 intensity=(Quantum) ((MagickRealType) GetPixelPacketIntensity(q) <
671 ((MagickRealType) QuantumRange/2.0) ? 0 : QuantumRange);
678 (void) SyncImage(image);
679 if ((cube_info->quantize_info->colorspace != UndefinedColorspace) &&
680 (cube_info->quantize_info->colorspace != CMYKColorspace))
681 (void) TransformImageColorspace((Image *) image,RGBColorspace);
686 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
690 + C l a s s i f y I m a g e C o l o r s %
694 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
696 % ClassifyImageColors() begins by initializing a color description tree
697 % of sufficient depth to represent each possible input color in a leaf.
698 % However, it is impractical to generate a fully-formed color
699 % description tree in the storage_class phase for realistic values of
700 % Cmax. If colors components in the input image are quantized to k-bit
701 % precision, so that Cmax= 2k-1, the tree would need k levels below the
702 % root node to allow representing each possible input color in a leaf.
703 % This becomes prohibitive because the tree's total number of nodes is
706 % A complete tree would require 19,173,961 nodes for k = 8, Cmax = 255.
707 % Therefore, to avoid building a fully populated tree, QUANTIZE: (1)
708 % Initializes data structures for nodes only as they are needed; (2)
709 % Chooses a maximum depth for the tree as a function of the desired
710 % number of colors in the output image (currently log2(colormap size)).
712 % For each pixel in the input image, storage_class scans downward from
713 % the root of the color description tree. At each level of the tree it
714 % identifies the single node which represents a cube in RGB space
715 % containing It updates the following data for each such node:
717 % n1 : Number of pixels whose color is contained in the RGB cube
718 % which this node represents;
720 % n2 : Number of pixels whose color is not represented in a node at
721 % lower depth in the tree; initially, n2 = 0 for all nodes except
722 % leaves of the tree.
724 % Sr, Sg, Sb : Sums of the red, green, and blue component values for
725 % all pixels not classified at a lower depth. The combination of
726 % these sums and n2 will ultimately characterize the mean color of a
727 % set of pixels represented by this node.
729 % E: the distance squared in RGB space between each pixel contained
730 % within a node and the nodes' center. This represents the quantization
733 % The format of the ClassifyImageColors() method is:
735 % MagickBooleanType ClassifyImageColors(CubeInfo *cube_info,
736 % const Image *image,ExceptionInfo *exception)
738 % A description of each parameter follows.
740 % o cube_info: A pointer to the Cube structure.
742 % o image: the image.
746 static inline void SetAssociatedAlpha(const Image *image,CubeInfo *cube_info)
751 associate_alpha=image->matte;
752 if (cube_info->quantize_info->colorspace == TransparentColorspace)
753 associate_alpha=MagickFalse;
754 if ((cube_info->quantize_info->number_colors == 2) &&
755 (cube_info->quantize_info->colorspace == GRAYColorspace))
756 associate_alpha=MagickFalse;
757 cube_info->associate_alpha=associate_alpha;
760 static MagickBooleanType ClassifyImageColors(CubeInfo *cube_info,
761 const Image *image,ExceptionInfo *exception)
763 #define ClassifyImageTag "Classify/Image"
793 Classify the first cube_info->maximum_colors colors to a tree depth of 8.
795 SetAssociatedAlpha(image,cube_info);
796 if ((cube_info->quantize_info->colorspace != UndefinedColorspace) &&
797 (cube_info->quantize_info->colorspace != CMYKColorspace))
798 (void) TransformImageColorspace((Image *) image,
799 cube_info->quantize_info->colorspace);
801 if ((image->colorspace != GRAYColorspace) &&
802 (image->colorspace != CMYColorspace) &&
803 (image->colorspace != RGBColorspace))
804 (void) TransformImageColorspace((Image *) image,RGBColorspace);
805 midpoint.red=(MagickRealType) QuantumRange/2.0;
806 midpoint.green=(MagickRealType) QuantumRange/2.0;
807 midpoint.blue=(MagickRealType) QuantumRange/2.0;
808 midpoint.alpha=(MagickRealType) QuantumRange/2.0;
810 image_view=AcquireCacheView(image);
811 for (y=0; y < (ssize_t) image->rows; y++)
813 register const Quantum
819 p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
820 if (p == (const Quantum *) NULL)
822 if (cube_info->nodes > MaxNodes)
825 Prune one level if the color tree is too large.
827 PruneLevel(image,cube_info,cube_info->root);
830 for (x=0; x < (ssize_t) image->columns; x+=(ssize_t) count)
833 Start at the root and descend the color cube tree.
835 for (count=1; (x+(ssize_t) count) < (ssize_t) image->columns; count++)
840 GetPixelPacket(image,p+count*GetPixelChannels(image),&packet);
841 if (IsPixelEquivalent(image,p,&packet) == MagickFalse)
844 AssociateAlphaPixel(image,cube_info,p,&pixel);
845 index=MaxTreeDepth-1;
846 bisect=((MagickRealType) QuantumRange+1.0)/2.0;
848 node_info=cube_info->root;
849 for (level=1; level <= MaxTreeDepth; level++)
852 id=ColorToNodeId(cube_info,&pixel,index);
853 mid.red+=(id & 1) != 0 ? bisect : -bisect;
854 mid.green+=(id & 2) != 0 ? bisect : -bisect;
855 mid.blue+=(id & 4) != 0 ? bisect : -bisect;
856 mid.alpha+=(id & 8) != 0 ? bisect : -bisect;
857 if (node_info->child[id] == (NodeInfo *) NULL)
860 Set colors of new node to contain pixel.
862 node_info->child[id]=GetNodeInfo(cube_info,id,level,node_info);
863 if (node_info->child[id] == (NodeInfo *) NULL)
864 (void) ThrowMagickException(exception,GetMagickModule(),
865 ResourceLimitError,"MemoryAllocationFailed","`%s'",
867 if (level == MaxTreeDepth)
871 Approximate the quantization error represented by this node.
873 node_info=node_info->child[id];
874 error.red=QuantumScale*(pixel.red-mid.red);
875 error.green=QuantumScale*(pixel.green-mid.green);
876 error.blue=QuantumScale*(pixel.blue-mid.blue);
877 if (cube_info->associate_alpha != MagickFalse)
878 error.alpha=QuantumScale*(pixel.alpha-mid.alpha);
879 node_info->quantize_error+=sqrt((double) (count*error.red*error.red+
880 count*error.green*error.green+count*error.blue*error.blue+
881 count*error.alpha*error.alpha));
882 cube_info->root->quantize_error+=node_info->quantize_error;
886 Sum RGB for this leaf for later derivation of the mean cube color.
888 node_info->number_unique+=count;
889 node_info->total_color.red+=count*QuantumScale*pixel.red;
890 node_info->total_color.green+=count*QuantumScale*pixel.green;
891 node_info->total_color.blue+=count*QuantumScale*pixel.blue;
892 if (cube_info->associate_alpha != MagickFalse)
893 node_info->total_color.alpha+=count*QuantumScale*pixel.alpha;
894 p+=count*GetPixelChannels(image);
896 if (cube_info->colors > cube_info->maximum_colors)
898 PruneToCubeDepth(image,cube_info,cube_info->root);
901 proceed=SetImageProgress(image,ClassifyImageTag,(MagickOffsetType) y,
903 if (proceed == MagickFalse)
906 for (y++; y < (ssize_t) image->rows; y++)
908 register const Quantum
914 p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
915 if (p == (const Quantum *) NULL)
917 if (cube_info->nodes > MaxNodes)
920 Prune one level if the color tree is too large.
922 PruneLevel(image,cube_info,cube_info->root);
925 for (x=0; x < (ssize_t) image->columns; x+=(ssize_t) count)
928 Start at the root and descend the color cube tree.
930 for (count=1; (x+(ssize_t) count) < (ssize_t) image->columns; count++)
935 GetPixelPacket(image,p+count*GetPixelChannels(image),&packet);
936 if (IsPixelEquivalent(image,p,&packet) == MagickFalse)
939 AssociateAlphaPixel(image,cube_info,p,&pixel);
940 index=MaxTreeDepth-1;
941 bisect=((MagickRealType) QuantumRange+1.0)/2.0;
943 node_info=cube_info->root;
944 for (level=1; level <= cube_info->depth; level++)
947 id=ColorToNodeId(cube_info,&pixel,index);
948 mid.red+=(id & 1) != 0 ? bisect : -bisect;
949 mid.green+=(id & 2) != 0 ? bisect : -bisect;
950 mid.blue+=(id & 4) != 0 ? bisect : -bisect;
951 mid.alpha+=(id & 8) != 0 ? bisect : -bisect;
952 if (node_info->child[id] == (NodeInfo *) NULL)
955 Set colors of new node to contain pixel.
957 node_info->child[id]=GetNodeInfo(cube_info,id,level,node_info);
958 if (node_info->child[id] == (NodeInfo *) NULL)
959 (void) ThrowMagickException(exception,GetMagickModule(),
960 ResourceLimitError,"MemoryAllocationFailed","%s",
962 if (level == cube_info->depth)
966 Approximate the quantization error represented by this node.
968 node_info=node_info->child[id];
969 error.red=QuantumScale*(pixel.red-mid.red);
970 error.green=QuantumScale*(pixel.green-mid.green);
971 error.blue=QuantumScale*(pixel.blue-mid.blue);
972 if (cube_info->associate_alpha != MagickFalse)
973 error.alpha=QuantumScale*(pixel.alpha-mid.alpha);
974 node_info->quantize_error+=sqrt((double) (count*error.red*error.red+
975 count*error.green*error.green+count*error.blue*error.blue+
976 count*error.alpha*error.alpha));
977 cube_info->root->quantize_error+=node_info->quantize_error;
981 Sum RGB for this leaf for later derivation of the mean cube color.
983 node_info->number_unique+=count;
984 node_info->total_color.red+=count*QuantumScale*pixel.red;
985 node_info->total_color.green+=count*QuantumScale*pixel.green;
986 node_info->total_color.blue+=count*QuantumScale*pixel.blue;
987 if (cube_info->associate_alpha != MagickFalse)
988 node_info->total_color.alpha+=count*QuantumScale*pixel.alpha;
989 p+=count*GetPixelChannels(image);
991 proceed=SetImageProgress(image,ClassifyImageTag,(MagickOffsetType) y,
993 if (proceed == MagickFalse)
996 image_view=DestroyCacheView(image_view);
997 if ((cube_info->quantize_info->colorspace != UndefinedColorspace) &&
998 (cube_info->quantize_info->colorspace != CMYKColorspace))
999 (void) TransformImageColorspace((Image *) image,RGBColorspace);
1004 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1008 % C l o n e Q u a n t i z e I n f o %
1012 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1014 % CloneQuantizeInfo() makes a duplicate of the given quantize info structure,
1015 % or if quantize info is NULL, a new one.
1017 % The format of the CloneQuantizeInfo method is:
1019 % QuantizeInfo *CloneQuantizeInfo(const QuantizeInfo *quantize_info)
1021 % A description of each parameter follows:
1023 % o clone_info: Method CloneQuantizeInfo returns a duplicate of the given
1024 % quantize info, or if image info is NULL a new one.
1026 % o quantize_info: a structure of type info.
1029 MagickExport QuantizeInfo *CloneQuantizeInfo(const QuantizeInfo *quantize_info)
1034 clone_info=(QuantizeInfo *) AcquireMagickMemory(sizeof(*clone_info));
1035 if (clone_info == (QuantizeInfo *) NULL)
1036 ThrowFatalException(ResourceLimitFatalError,"MemoryAllocationFailed");
1037 GetQuantizeInfo(clone_info);
1038 if (quantize_info == (QuantizeInfo *) NULL)
1040 clone_info->number_colors=quantize_info->number_colors;
1041 clone_info->tree_depth=quantize_info->tree_depth;
1042 clone_info->dither=quantize_info->dither;
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)
1099 register MagickRealType
1104 register PixelPacket
1107 register RealPixelPacket
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=(MagickRealType) (QuantumScale*p->alpha);
1120 beta=(MagickRealType) (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)
1165 % A description of each parameter follows:
1167 % o image: the image.
1170 MagickExport MagickBooleanType CompressImageColormap(Image *image)
1175 assert(image != (Image *) NULL);
1176 assert(image->signature == MagickSignature);
1177 if (image->debug != MagickFalse)
1178 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1179 if (IsPaletteImage(image,&image->exception) == MagickFalse)
1180 return(MagickFalse);
1181 GetQuantizeInfo(&quantize_info);
1182 quantize_info.number_colors=image->colors;
1183 quantize_info.tree_depth=MaxTreeDepth;
1184 return(QuantizeImage(&quantize_info,image));
1188 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1192 + D e f i n e I m a g e C o l o r m a p %
1196 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1198 % DefineImageColormap() traverses the color cube tree and notes each colormap
1199 % entry. A colormap entry is any node in the color cube tree where the
1200 % of unique colors is not zero. DefineImageColormap() returns the number of
1201 % colors in the image colormap.
1203 % The format of the DefineImageColormap method is:
1205 % size_t DefineImageColormap(Image *image,CubeInfo *cube_info,
1206 % NodeInfo *node_info)
1208 % A description of each parameter follows.
1210 % o image: the image.
1212 % o cube_info: A pointer to the Cube structure.
1214 % o node_info: the address of a structure of type NodeInfo which points to a
1215 % node in the color cube tree that is to be pruned.
1218 static size_t DefineImageColormap(Image *image,CubeInfo *cube_info,
1219 NodeInfo *node_info)
1228 Traverse any children.
1230 number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
1231 for (i=0; i < (ssize_t) number_children; i++)
1232 if (node_info->child[i] != (NodeInfo *) NULL)
1233 (void) DefineImageColormap(image,cube_info,node_info->child[i]);
1234 if (node_info->number_unique != 0)
1236 register MagickRealType
1239 register PixelPacket
1243 Colormap entry is defined by the mean color in this cube.
1245 q=image->colormap+image->colors;
1246 alpha=(MagickRealType) ((MagickOffsetType) node_info->number_unique);
1247 alpha=1.0/(fabs(alpha) <= MagickEpsilon ? 1.0 : alpha);
1248 if (cube_info->associate_alpha == MagickFalse)
1250 q->red=ClampToQuantum((MagickRealType)
1251 (alpha*QuantumRange*node_info->total_color.red));
1252 q->green=ClampToQuantum((MagickRealType)
1253 (alpha*QuantumRange*node_info->total_color.green));
1254 q->blue=ClampToQuantum((MagickRealType)
1255 (alpha*QuantumRange*node_info->total_color.blue));
1256 q->alpha=OpaqueAlpha;
1263 opacity=(MagickRealType) (alpha*QuantumRange*
1264 node_info->total_color.alpha);
1265 q->alpha=ClampToQuantum(opacity);
1266 if (q->alpha == OpaqueAlpha)
1268 q->red=ClampToQuantum((MagickRealType)
1269 (alpha*QuantumRange*node_info->total_color.red));
1270 q->green=ClampToQuantum((MagickRealType)
1271 (alpha*QuantumRange*node_info->total_color.green));
1272 q->blue=ClampToQuantum((MagickRealType)
1273 (alpha*QuantumRange*node_info->total_color.blue));
1280 gamma=(MagickRealType) (QuantumScale*q->alpha);
1281 gamma=1.0/(fabs(gamma) <= MagickEpsilon ? 1.0 : gamma);
1282 q->red=ClampToQuantum((MagickRealType)
1283 (alpha*gamma*QuantumRange*node_info->total_color.red));
1284 q->green=ClampToQuantum((MagickRealType)
1285 (alpha*gamma*QuantumRange*node_info->total_color.green));
1286 q->blue=ClampToQuantum((MagickRealType)
1287 (alpha*gamma*QuantumRange*node_info->total_color.blue));
1288 if (node_info->number_unique > cube_info->transparent_pixels)
1290 cube_info->transparent_pixels=node_info->number_unique;
1291 cube_info->transparent_index=(ssize_t) image->colors;
1295 node_info->color_number=image->colors++;
1297 return(image->colors);
1301 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1305 + D e s t r o y C u b e I n f o %
1309 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1311 % DestroyCubeInfo() deallocates memory associated with an image.
1313 % The format of the DestroyCubeInfo method is:
1315 % DestroyCubeInfo(CubeInfo *cube_info)
1317 % A description of each parameter follows:
1319 % o cube_info: the address of a structure of type CubeInfo.
1322 static void DestroyCubeInfo(CubeInfo *cube_info)
1328 Release color cube tree storage.
1332 nodes=cube_info->node_queue->next;
1333 cube_info->node_queue->nodes=(NodeInfo *) RelinquishMagickMemory(
1334 cube_info->node_queue->nodes);
1335 cube_info->node_queue=(Nodes *) RelinquishMagickMemory(
1336 cube_info->node_queue);
1337 cube_info->node_queue=nodes;
1338 } while (cube_info->node_queue != (Nodes *) NULL);
1339 if (cube_info->cache != (ssize_t *) NULL)
1340 cube_info->cache=(ssize_t *) RelinquishMagickMemory(cube_info->cache);
1341 cube_info->quantize_info=DestroyQuantizeInfo(cube_info->quantize_info);
1342 cube_info=(CubeInfo *) RelinquishMagickMemory(cube_info);
1346 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1350 % D e s t r o y Q u a n t i z e I n f o %
1354 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1356 % DestroyQuantizeInfo() deallocates memory associated with an QuantizeInfo
1359 % The format of the DestroyQuantizeInfo method is:
1361 % QuantizeInfo *DestroyQuantizeInfo(QuantizeInfo *quantize_info)
1363 % A description of each parameter follows:
1365 % o quantize_info: Specifies a pointer to an QuantizeInfo structure.
1368 MagickExport QuantizeInfo *DestroyQuantizeInfo(QuantizeInfo *quantize_info)
1370 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"...");
1371 assert(quantize_info != (QuantizeInfo *) NULL);
1372 assert(quantize_info->signature == MagickSignature);
1373 quantize_info->signature=(~MagickSignature);
1374 quantize_info=(QuantizeInfo *) RelinquishMagickMemory(quantize_info);
1375 return(quantize_info);
1379 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1383 + D i t h e r I m a g e %
1387 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1389 % DitherImage() distributes the difference between an original image and
1390 % the corresponding color reduced algorithm to neighboring pixels using
1391 % serpentine-scan Floyd-Steinberg error diffusion. DitherImage returns
1392 % MagickTrue if the image is dithered otherwise MagickFalse.
1394 % The format of the DitherImage method is:
1396 % MagickBooleanType DitherImage(Image *image,CubeInfo *cube_info)
1398 % A description of each parameter follows.
1400 % o image: the image.
1402 % o cube_info: A pointer to the Cube structure.
1406 static RealPixelPacket **DestroyPixelThreadSet(RealPixelPacket **pixels)
1411 assert(pixels != (RealPixelPacket **) NULL);
1412 for (i=0; i < (ssize_t) GetOpenMPMaximumThreads(); i++)
1413 if (pixels[i] != (RealPixelPacket *) NULL)
1414 pixels[i]=(RealPixelPacket *) RelinquishMagickMemory(pixels[i]);
1415 pixels=(RealPixelPacket **) RelinquishMagickMemory(pixels);
1419 static RealPixelPacket **AcquirePixelThreadSet(const size_t count)
1430 number_threads=GetOpenMPMaximumThreads();
1431 pixels=(RealPixelPacket **) AcquireQuantumMemory(number_threads,
1433 if (pixels == (RealPixelPacket **) NULL)
1434 return((RealPixelPacket **) NULL);
1435 (void) ResetMagickMemory(pixels,0,number_threads*sizeof(*pixels));
1436 for (i=0; i < (ssize_t) number_threads; i++)
1438 pixels[i]=(RealPixelPacket *) AcquireQuantumMemory(count,
1439 2*sizeof(**pixels));
1440 if (pixels[i] == (RealPixelPacket *) NULL)
1441 return(DestroyPixelThreadSet(pixels));
1446 static inline ssize_t CacheOffset(CubeInfo *cube_info,
1447 const RealPixelPacket *pixel)
1449 #define RedShift(pixel) (((pixel) >> CacheShift) << (0*(8-CacheShift)))
1450 #define GreenShift(pixel) (((pixel) >> CacheShift) << (1*(8-CacheShift)))
1451 #define BlueShift(pixel) (((pixel) >> CacheShift) << (2*(8-CacheShift)))
1452 #define AlphaShift(pixel) (((pixel) >> CacheShift) << (3*(8-CacheShift)))
1458 (RedShift(ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->red))) |
1459 GreenShift(ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->green))) |
1460 BlueShift(ScaleQuantumToChar(ClampToUnsignedQuantum(pixel->blue))));
1461 if (cube_info->associate_alpha != MagickFalse)
1462 offset|=AlphaShift(ScaleQuantumToChar(ClampToUnsignedQuantum(
1467 static MagickBooleanType FloydSteinbergDither(Image *image,CubeInfo *cube_info)
1469 #define DitherImageTag "Dither/Image"
1487 Distribute quantization error using Floyd-Steinberg.
1489 pixels=AcquirePixelThreadSet(image->columns);
1490 if (pixels == (RealPixelPacket **) NULL)
1491 return(MagickFalse);
1492 exception=(&image->exception);
1494 image_view=AcquireCacheView(image);
1495 for (y=0; y < (ssize_t) image->rows; y++)
1498 id = GetOpenMPThreadId();
1519 if (status == MagickFalse)
1521 q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
1522 if (q == (const Quantum *) NULL)
1527 q+=(y & 0x01)*image->columns*GetPixelChannels(image);
1529 current=pixels[id]+(y & 0x01)*image->columns;
1530 previous=pixels[id]+((y+1) & 0x01)*image->columns;
1531 v=(ssize_t) ((y & 0x01) != 0 ? -1 : 1);
1532 for (x=0; x < (ssize_t) image->columns; x++)
1544 q-=(y & 0x01)*GetPixelChannels(image);
1545 u=(y & 0x01) != 0 ? (ssize_t) image->columns-1-x : x;
1546 AssociateAlphaPixel(image,&cube,q,&pixel);
1549 pixel.red+=7*current[u-v].red/16;
1550 pixel.green+=7*current[u-v].green/16;
1551 pixel.blue+=7*current[u-v].blue/16;
1552 if (cube.associate_alpha != MagickFalse)
1553 pixel.alpha+=7*current[u-v].alpha/16;
1557 if (x < (ssize_t) (image->columns-1))
1559 pixel.red+=previous[u+v].red/16;
1560 pixel.green+=previous[u+v].green/16;
1561 pixel.blue+=previous[u+v].blue/16;
1562 if (cube.associate_alpha != MagickFalse)
1563 pixel.alpha+=previous[u+v].alpha/16;
1565 pixel.red+=5*previous[u].red/16;
1566 pixel.green+=5*previous[u].green/16;
1567 pixel.blue+=5*previous[u].blue/16;
1568 if (cube.associate_alpha != MagickFalse)
1569 pixel.alpha+=5*previous[u].alpha/16;
1572 pixel.red+=3*previous[u-v].red/16;
1573 pixel.green+=3*previous[u-v].green/16;
1574 pixel.blue+=3*previous[u-v].blue/16;
1575 if (cube.associate_alpha != MagickFalse)
1576 pixel.alpha+=3*previous[u-v].alpha/16;
1579 pixel.red=(MagickRealType) ClampToUnsignedQuantum(pixel.red);
1580 pixel.green=(MagickRealType) ClampToUnsignedQuantum(pixel.green);
1581 pixel.blue=(MagickRealType) ClampToUnsignedQuantum(pixel.blue);
1582 if (cube.associate_alpha != MagickFalse)
1583 pixel.alpha=(MagickRealType) ClampToUnsignedQuantum(pixel.alpha);
1584 i=CacheOffset(&cube,&pixel);
1585 if (cube.cache[i] < 0)
1594 Identify the deepest node containing the pixel's color.
1596 node_info=cube.root;
1597 for (index=MaxTreeDepth-1; (ssize_t) index > 0; index--)
1599 id=ColorToNodeId(&cube,&pixel,index);
1600 if (node_info->child[id] == (NodeInfo *) NULL)
1602 node_info=node_info->child[id];
1605 Find closest color among siblings and their children.
1608 cube.distance=(MagickRealType) (4.0*(QuantumRange+1.0)*(QuantumRange+
1610 ClosestColor(image,&cube,node_info->parent);
1611 cube.cache[i]=(ssize_t) cube.color_number;
1614 Assign pixel to closest colormap entry.
1616 index=(size_t) cube.cache[i];
1617 if (image->storage_class == PseudoClass)
1618 SetPixelIndex(image,(Quantum) index,q);
1619 if (cube.quantize_info->measure_error == MagickFalse)
1621 SetPixelRed(image,image->colormap[index].red,q);
1622 SetPixelGreen(image,image->colormap[index].green,q);
1623 SetPixelBlue(image,image->colormap[index].blue,q);
1624 if (cube.associate_alpha != MagickFalse)
1625 SetPixelAlpha(image,image->colormap[index].alpha,q);
1627 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1632 AssociateAlphaPixelPacket(image,&cube,image->colormap+index,&color);
1633 current[u].red=pixel.red-color.red;
1634 current[u].green=pixel.green-color.green;
1635 current[u].blue=pixel.blue-color.blue;
1636 if (cube.associate_alpha != MagickFalse)
1637 current[u].alpha=pixel.alpha-color.alpha;
1638 if (image->progress_monitor != (MagickProgressMonitor) NULL)
1643 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1644 #pragma omp critical (MagickCore_FloydSteinbergDither)
1646 proceed=SetImageProgress(image,DitherImageTag,(MagickOffsetType) y,
1648 if (proceed == MagickFalse)
1651 q+=((y+1) & 0x01)*GetPixelChannels(image);
1654 image_view=DestroyCacheView(image_view);
1655 pixels=DestroyPixelThreadSet(pixels);
1659 static MagickBooleanType
1660 RiemersmaDither(Image *,CacheView *,CubeInfo *,const unsigned int);
1662 static void Riemersma(Image *image,CacheView *image_view,CubeInfo *cube_info,
1663 const size_t level,const unsigned int direction)
1670 (void) RiemersmaDither(image,image_view,cube_info,EastGravity);
1671 (void) RiemersmaDither(image,image_view,cube_info,SouthGravity);
1672 (void) RiemersmaDither(image,image_view,cube_info,WestGravity);
1677 (void) RiemersmaDither(image,image_view,cube_info,WestGravity);
1678 (void) RiemersmaDither(image,image_view,cube_info,NorthGravity);
1679 (void) RiemersmaDither(image,image_view,cube_info,EastGravity);
1684 (void) RiemersmaDither(image,image_view,cube_info,SouthGravity);
1685 (void) RiemersmaDither(image,image_view,cube_info,EastGravity);
1686 (void) RiemersmaDither(image,image_view,cube_info,NorthGravity);
1691 (void) RiemersmaDither(image,image_view,cube_info,NorthGravity);
1692 (void) RiemersmaDither(image,image_view,cube_info,WestGravity);
1693 (void) RiemersmaDither(image,image_view,cube_info,SouthGravity);
1704 Riemersma(image,image_view,cube_info,level-1,NorthGravity);
1705 (void) RiemersmaDither(image,image_view,cube_info,EastGravity);
1706 Riemersma(image,image_view,cube_info,level-1,WestGravity);
1707 (void) RiemersmaDither(image,image_view,cube_info,SouthGravity);
1708 Riemersma(image,image_view,cube_info,level-1,WestGravity);
1709 (void) RiemersmaDither(image,image_view,cube_info,WestGravity);
1710 Riemersma(image,image_view,cube_info,level-1,SouthGravity);
1715 Riemersma(image,image_view,cube_info,level-1,SouthGravity);
1716 (void) RiemersmaDither(image,image_view,cube_info,WestGravity);
1717 Riemersma(image,image_view,cube_info,level-1,EastGravity);
1718 (void) RiemersmaDither(image,image_view,cube_info,NorthGravity);
1719 Riemersma(image,image_view,cube_info,level-1,EastGravity);
1720 (void) RiemersmaDither(image,image_view,cube_info,EastGravity);
1721 Riemersma(image,image_view,cube_info,level-1,NorthGravity);
1726 Riemersma(image,image_view,cube_info,level-1,WestGravity);
1727 (void) RiemersmaDither(image,image_view,cube_info,SouthGravity);
1728 Riemersma(image,image_view,cube_info,level-1,NorthGravity);
1729 (void) RiemersmaDither(image,image_view,cube_info,EastGravity);
1730 Riemersma(image,image_view,cube_info,level-1,NorthGravity);
1731 (void) RiemersmaDither(image,image_view,cube_info,NorthGravity);
1732 Riemersma(image,image_view,cube_info,level-1,EastGravity);
1737 Riemersma(image,image_view,cube_info,level-1,EastGravity);
1738 (void) RiemersmaDither(image,image_view,cube_info,NorthGravity);
1739 Riemersma(image,image_view,cube_info,level-1,SouthGravity);
1740 (void) RiemersmaDither(image,image_view,cube_info,WestGravity);
1741 Riemersma(image,image_view,cube_info,level-1,SouthGravity);
1742 (void) RiemersmaDither(image,image_view,cube_info,SouthGravity);
1743 Riemersma(image,image_view,cube_info,level-1,WestGravity);
1751 static MagickBooleanType RiemersmaDither(Image *image,CacheView *image_view,
1752 CubeInfo *cube_info,const unsigned int direction)
1754 #define DitherImageTag "Dither/Image"
1770 if ((p->x >= 0) && (p->x < (ssize_t) image->columns) &&
1771 (p->y >= 0) && (p->y < (ssize_t) image->rows))
1785 exception=(&image->exception);
1786 q=GetCacheViewAuthenticPixels(image_view,p->x,p->y,1,1,exception);
1787 if (q == (const Quantum *) NULL)
1788 return(MagickFalse);
1789 AssociateAlphaPixel(image,cube_info,q,&pixel);
1790 for (i=0; i < ErrorQueueLength; i++)
1792 pixel.red+=p->weights[i]*p->error[i].red;
1793 pixel.green+=p->weights[i]*p->error[i].green;
1794 pixel.blue+=p->weights[i]*p->error[i].blue;
1795 if (cube_info->associate_alpha != MagickFalse)
1796 pixel.alpha+=p->weights[i]*p->error[i].alpha;
1798 pixel.red=(MagickRealType) ClampToUnsignedQuantum(pixel.red);
1799 pixel.green=(MagickRealType) ClampToUnsignedQuantum(pixel.green);
1800 pixel.blue=(MagickRealType) ClampToUnsignedQuantum(pixel.blue);
1801 if (cube_info->associate_alpha != MagickFalse)
1802 pixel.alpha=(MagickRealType) ClampToUnsignedQuantum(pixel.alpha);
1803 i=CacheOffset(cube_info,&pixel);
1804 if (p->cache[i] < 0)
1813 Identify the deepest node containing the pixel's color.
1816 for (index=MaxTreeDepth-1; (ssize_t) index > 0; index--)
1818 id=ColorToNodeId(cube_info,&pixel,index);
1819 if (node_info->child[id] == (NodeInfo *) NULL)
1821 node_info=node_info->child[id];
1823 node_info=node_info->parent;
1825 Find closest color among siblings and their children.
1828 p->distance=(MagickRealType) (4.0*(QuantumRange+1.0)*((MagickRealType)
1829 QuantumRange+1.0)+1.0);
1830 ClosestColor(image,p,node_info->parent);
1831 p->cache[i]=(ssize_t) p->color_number;
1834 Assign pixel to closest colormap entry.
1836 index=(size_t) p->cache[i];
1837 if (image->storage_class == PseudoClass)
1838 SetPixelIndex(image,(Quantum) index,q);
1839 if (cube_info->quantize_info->measure_error == MagickFalse)
1841 SetPixelRed(image,image->colormap[index].red,q);
1842 SetPixelGreen(image,image->colormap[index].green,q);
1843 SetPixelBlue(image,image->colormap[index].blue,q);
1844 if (cube_info->associate_alpha != MagickFalse)
1845 SetPixelAlpha(image,image->colormap[index].alpha,q);
1847 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1848 return(MagickFalse);
1850 Propagate the error as the last entry of the error queue.
1852 (void) CopyMagickMemory(p->error,p->error+1,(ErrorQueueLength-1)*
1853 sizeof(p->error[0]));
1854 AssociateAlphaPixelPacket(image,cube_info,image->colormap+index,&color);
1855 p->error[ErrorQueueLength-1].red=pixel.red-color.red;
1856 p->error[ErrorQueueLength-1].green=pixel.green-color.green;
1857 p->error[ErrorQueueLength-1].blue=pixel.blue-color.blue;
1858 if (cube_info->associate_alpha != MagickFalse)
1859 p->error[ErrorQueueLength-1].alpha=pixel.alpha-color.alpha;
1860 proceed=SetImageProgress(image,DitherImageTag,p->offset,p->span);
1861 if (proceed == MagickFalse)
1862 return(MagickFalse);
1867 case WestGravity: p->x--; break;
1868 case EastGravity: p->x++; break;
1869 case NorthGravity: p->y--; break;
1870 case SouthGravity: p->y++; break;
1875 static inline ssize_t MagickMax(const ssize_t x,const ssize_t y)
1882 static inline ssize_t MagickMin(const ssize_t x,const ssize_t y)
1889 static MagickBooleanType DitherImage(Image *image,CubeInfo *cube_info)
1903 if (cube_info->quantize_info->dither_method != RiemersmaDitherMethod)
1904 return(FloydSteinbergDither(image,cube_info));
1906 Distribute quantization error along a Hilbert curve.
1908 (void) ResetMagickMemory(cube_info->error,0,ErrorQueueLength*
1909 sizeof(*cube_info->error));
1912 i=MagickMax((ssize_t) image->columns,(ssize_t) image->rows);
1913 for (depth=1; i != 0; depth++)
1915 if ((ssize_t) (1L << depth) < MagickMax((ssize_t) image->columns,(ssize_t) image->rows))
1917 cube_info->offset=0;
1918 cube_info->span=(MagickSizeType) image->columns*image->rows;
1919 image_view=AcquireCacheView(image);
1921 Riemersma(image,image_view,cube_info,depth-1,NorthGravity);
1922 status=RiemersmaDither(image,image_view,cube_info,ForgetGravity);
1923 image_view=DestroyCacheView(image_view);
1928 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1932 + G e t C u b e I n f o %
1936 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1938 % GetCubeInfo() initialize the Cube data structure.
1940 % The format of the GetCubeInfo method is:
1942 % CubeInfo GetCubeInfo(const QuantizeInfo *quantize_info,
1943 % const size_t depth,const size_t maximum_colors)
1945 % A description of each parameter follows.
1947 % o quantize_info: Specifies a pointer to an QuantizeInfo structure.
1949 % o depth: Normally, this integer value is zero or one. A zero or
1950 % one tells Quantize to choose a optimal tree depth of Log4(number_colors).
1951 % A tree of this depth generally allows the best representation of the
1952 % reference image with the least amount of memory and the fastest
1953 % computational speed. In some cases, such as an image with low color
1954 % dispersion (a few number of colors), a value other than
1955 % Log4(number_colors) is required. To expand the color tree completely,
1958 % o maximum_colors: maximum colors.
1961 static CubeInfo *GetCubeInfo(const QuantizeInfo *quantize_info,
1962 const size_t depth,const size_t maximum_colors)
1978 Initialize tree to describe color cube_info.
1980 cube_info=(CubeInfo *) AcquireMagickMemory(sizeof(*cube_info));
1981 if (cube_info == (CubeInfo *) NULL)
1982 return((CubeInfo *) NULL);
1983 (void) ResetMagickMemory(cube_info,0,sizeof(*cube_info));
1984 cube_info->depth=depth;
1985 if (cube_info->depth > MaxTreeDepth)
1986 cube_info->depth=MaxTreeDepth;
1987 if (cube_info->depth < 2)
1989 cube_info->maximum_colors=maximum_colors;
1991 Initialize root node.
1993 cube_info->root=GetNodeInfo(cube_info,0,0,(NodeInfo *) NULL);
1994 if (cube_info->root == (NodeInfo *) NULL)
1995 return((CubeInfo *) NULL);
1996 cube_info->root->parent=cube_info->root;
1997 cube_info->quantize_info=CloneQuantizeInfo(quantize_info);
1998 if (cube_info->quantize_info->dither == MagickFalse)
2001 Initialize dither resources.
2003 length=(size_t) (1UL << (4*(8-CacheShift)));
2004 cube_info->cache=(ssize_t *) AcquireQuantumMemory(length,
2005 sizeof(*cube_info->cache));
2006 if (cube_info->cache == (ssize_t *) NULL)
2007 return((CubeInfo *) NULL);
2009 Initialize color cache.
2011 for (i=0; i < (ssize_t) length; i++)
2012 cube_info->cache[i]=(-1);
2014 Distribute weights along a curve of exponential decay.
2017 for (i=0; i < ErrorQueueLength; i++)
2019 cube_info->weights[ErrorQueueLength-i-1]=1.0/weight;
2020 weight*=exp(log(((double) QuantumRange+1.0))/(ErrorQueueLength-1.0));
2023 Normalize the weighting factors.
2026 for (i=0; i < ErrorQueueLength; i++)
2027 weight+=cube_info->weights[i];
2029 for (i=0; i < ErrorQueueLength; i++)
2031 cube_info->weights[i]/=weight;
2032 sum+=cube_info->weights[i];
2034 cube_info->weights[0]+=1.0-sum;
2039 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2043 + G e t N o d e I n f o %
2047 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2049 % GetNodeInfo() allocates memory for a new node in the color cube tree and
2050 % presets all fields to zero.
2052 % The format of the GetNodeInfo method is:
2054 % NodeInfo *GetNodeInfo(CubeInfo *cube_info,const size_t id,
2055 % const size_t level,NodeInfo *parent)
2057 % A description of each parameter follows.
2059 % o node: The GetNodeInfo method returns a pointer to a queue of nodes.
2061 % o id: Specifies the child number of the node.
2063 % o level: Specifies the level in the storage_class the node resides.
2066 static NodeInfo *GetNodeInfo(CubeInfo *cube_info,const size_t id,
2067 const size_t level,NodeInfo *parent)
2072 if (cube_info->free_nodes == 0)
2078 Allocate a new queue of nodes.
2080 nodes=(Nodes *) AcquireMagickMemory(sizeof(*nodes));
2081 if (nodes == (Nodes *) NULL)
2082 return((NodeInfo *) NULL);
2083 nodes->nodes=(NodeInfo *) AcquireQuantumMemory(NodesInAList,
2084 sizeof(*nodes->nodes));
2085 if (nodes->nodes == (NodeInfo *) NULL)
2086 return((NodeInfo *) NULL);
2087 nodes->next=cube_info->node_queue;
2088 cube_info->node_queue=nodes;
2089 cube_info->next_node=nodes->nodes;
2090 cube_info->free_nodes=NodesInAList;
2093 cube_info->free_nodes--;
2094 node_info=cube_info->next_node++;
2095 (void) ResetMagickMemory(node_info,0,sizeof(*node_info));
2096 node_info->parent=parent;
2098 node_info->level=level;
2103 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2107 % G e t I m a g e Q u a n t i z e E r r o r %
2111 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2113 % GetImageQuantizeError() measures the difference between the original
2114 % and quantized images. This difference is the total quantization error.
2115 % The error is computed by summing over all pixels in an image the distance
2116 % squared in RGB space between each reference pixel value and its quantized
2117 % value. These values are computed:
2119 % o mean_error_per_pixel: This value is the mean error for any single
2120 % pixel in the image.
2122 % o normalized_mean_square_error: This value is the normalized mean
2123 % quantization error for any single pixel in the image. This distance
2124 % measure is normalized to a range between 0 and 1. It is independent
2125 % of the range of red, green, and blue values in the image.
2127 % o normalized_maximum_square_error: Thsi value is the normalized
2128 % maximum quantization error for any single pixel in the image. This
2129 % distance measure is normalized to a range between 0 and 1. It is
2130 % independent of the range of red, green, and blue values in your image.
2132 % The format of the GetImageQuantizeError method is:
2134 % MagickBooleanType GetImageQuantizeError(Image *image)
2136 % A description of each parameter follows.
2138 % o image: the image.
2141 MagickExport MagickBooleanType GetImageQuantizeError(Image *image)
2156 mean_error_per_pixel;
2164 assert(image != (Image *) NULL);
2165 assert(image->signature == MagickSignature);
2166 if (image->debug != MagickFalse)
2167 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
2168 image->total_colors=GetNumberColors(image,(FILE *) NULL,&image->exception);
2169 (void) ResetMagickMemory(&image->error,0,sizeof(image->error));
2170 if (image->storage_class == DirectClass)
2174 area=3.0*image->columns*image->rows;
2176 mean_error_per_pixel=0.0;
2178 exception=(&image->exception);
2179 image_view=AcquireCacheView(image);
2180 for (y=0; y < (ssize_t) image->rows; y++)
2182 register const Quantum
2188 p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
2189 if (p == (const Quantum *) NULL)
2191 for (x=0; x < (ssize_t) image->columns; x++)
2193 index=1UL*GetPixelIndex(image,p);
2194 if (image->matte != MagickFalse)
2196 alpha=(MagickRealType) (QuantumScale*GetPixelAlpha(image,p));
2197 beta=(MagickRealType) (QuantumScale*image->colormap[index].alpha);
2199 distance=fabs(alpha*GetPixelRed(image,p)-beta*
2200 image->colormap[index].red);
2201 mean_error_per_pixel+=distance;
2202 mean_error+=distance*distance;
2203 if (distance > maximum_error)
2204 maximum_error=distance;
2205 distance=fabs(alpha*GetPixelGreen(image,p)-beta*
2206 image->colormap[index].green);
2207 mean_error_per_pixel+=distance;
2208 mean_error+=distance*distance;
2209 if (distance > maximum_error)
2210 maximum_error=distance;
2211 distance=fabs(alpha*GetPixelBlue(image,p)-beta*
2212 image->colormap[index].blue);
2213 mean_error_per_pixel+=distance;
2214 mean_error+=distance*distance;
2215 if (distance > maximum_error)
2216 maximum_error=distance;
2217 p+=GetPixelChannels(image);
2220 image_view=DestroyCacheView(image_view);
2221 image->error.mean_error_per_pixel=(double) mean_error_per_pixel/area;
2222 image->error.normalized_mean_error=(double) QuantumScale*QuantumScale*
2224 image->error.normalized_maximum_error=(double) QuantumScale*maximum_error;
2229 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2233 % G e t Q u a n t i z e I n f o %
2237 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2239 % GetQuantizeInfo() initializes the QuantizeInfo structure.
2241 % The format of the GetQuantizeInfo method is:
2243 % GetQuantizeInfo(QuantizeInfo *quantize_info)
2245 % A description of each parameter follows:
2247 % o quantize_info: Specifies a pointer to a QuantizeInfo structure.
2250 MagickExport void GetQuantizeInfo(QuantizeInfo *quantize_info)
2252 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"...");
2253 assert(quantize_info != (QuantizeInfo *) NULL);
2254 (void) ResetMagickMemory(quantize_info,0,sizeof(*quantize_info));
2255 quantize_info->number_colors=256;
2256 quantize_info->dither=MagickTrue;
2257 quantize_info->dither_method=RiemersmaDitherMethod;
2258 quantize_info->colorspace=UndefinedColorspace;
2259 quantize_info->measure_error=MagickFalse;
2260 quantize_info->signature=MagickSignature;
2264 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2268 % P o s t e r i z e I m a g e C h a n n e l %
2272 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2274 % PosterizeImage() reduces the image to a limited number of colors for a
2277 % The format of the PosterizeImage method is:
2279 % MagickBooleanType PosterizeImage(Image *image,const size_t levels,
2280 % const MagickBooleanType dither)
2281 % MagickBooleanType PosterizeImageChannel(Image *image,
2282 % const ChannelType channel,const size_t levels,
2283 % const MagickBooleanType dither)
2285 % A description of each parameter follows:
2287 % o image: Specifies a pointer to an Image structure.
2289 % o levels: Number of color levels allowed in each channel. Very low values
2290 % (2, 3, or 4) have the most visible effect.
2292 % o dither: Set this integer value to something other than zero to dither
2297 static inline ssize_t MagickRound(MagickRealType x)
2300 Round the fraction to nearest integer.
2303 return((ssize_t) (x+0.5));
2304 return((ssize_t) (x-0.5));
2307 MagickExport MagickBooleanType PosterizeImage(Image *image,const size_t levels,
2308 const MagickBooleanType dither)
2313 status=PosterizeImageChannel(image,DefaultChannels,levels,dither);
2317 MagickExport MagickBooleanType PosterizeImageChannel(Image *image,
2318 const ChannelType channel,const size_t levels,const MagickBooleanType dither)
2320 #define PosterizeImageTag "Posterize/Image"
2321 #define PosterizePixel(pixel) (Quantum) (QuantumRange*(MagickRound( \
2322 QuantumScale*pixel*(levels-1)))/MagickMax((ssize_t) levels-1,1))
2345 assert(image != (Image *) NULL);
2346 assert(image->signature == MagickSignature);
2347 if (image->debug != MagickFalse)
2348 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
2349 if (image->storage_class == PseudoClass)
2350 #if defined(MAGICKCORE_OPENMP_SUPPORT)
2351 #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
2353 for (i=0; i < (ssize_t) image->colors; i++)
2358 if ((channel & RedChannel) != 0)
2359 image->colormap[i].red=PosterizePixel(image->colormap[i].red);
2360 if ((channel & GreenChannel) != 0)
2361 image->colormap[i].green=PosterizePixel(image->colormap[i].green);
2362 if ((channel & BlueChannel) != 0)
2363 image->colormap[i].blue=PosterizePixel(image->colormap[i].blue);
2364 if ((channel & OpacityChannel) != 0)
2365 image->colormap[i].alpha=PosterizePixel(image->colormap[i].alpha);
2372 exception=(&image->exception);
2373 image_view=AcquireCacheView(image);
2374 #if defined(MAGICKCORE_OPENMP_SUPPORT)
2375 #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
2377 for (y=0; y < (ssize_t) image->rows; y++)
2385 if (status == MagickFalse)
2387 q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
2388 if (q == (const Quantum *) NULL)
2393 for (x=0; x < (ssize_t) image->columns; x++)
2395 if ((channel & RedChannel) != 0)
2396 SetPixelRed(image,PosterizePixel(GetPixelRed(image,q)),q);
2397 if ((channel & GreenChannel) != 0)
2398 SetPixelGreen(image,PosterizePixel(GetPixelGreen(image,q)),q);
2399 if ((channel & BlueChannel) != 0)
2400 SetPixelBlue(image,PosterizePixel(GetPixelBlue(image,q)),q);
2401 if (((channel & BlackChannel) != 0) &&
2402 (image->colorspace == CMYKColorspace))
2403 SetPixelBlack(image,PosterizePixel(GetPixelBlack(image,q)),q);
2404 if (((channel & OpacityChannel) != 0) &&
2405 (image->matte == MagickTrue))
2406 SetPixelAlpha(image,PosterizePixel(GetPixelAlpha(image,q)),q);
2407 q+=GetPixelChannels(image);
2409 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
2411 if (image->progress_monitor != (MagickProgressMonitor) NULL)
2416 #if defined(MAGICKCORE_OPENMP_SUPPORT)
2417 #pragma omp critical (MagickCore_PosterizeImageChannel)
2419 proceed=SetImageProgress(image,PosterizeImageTag,progress++,
2421 if (proceed == MagickFalse)
2425 image_view=DestroyCacheView(image_view);
2426 quantize_info=AcquireQuantizeInfo((ImageInfo *) NULL);
2427 quantize_info->number_colors=(size_t) MagickMin((ssize_t) levels*levels*
2428 levels,MaxColormapSize+1);
2429 quantize_info->dither=dither;
2430 quantize_info->tree_depth=MaxTreeDepth;
2431 status=QuantizeImage(quantize_info,image);
2432 quantize_info=DestroyQuantizeInfo(quantize_info);
2437 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2441 + P r u n e C h i l d %
2445 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2447 % PruneChild() deletes the given node and merges its statistics into its
2450 % The format of the PruneSubtree method is:
2452 % PruneChild(const Image *image,CubeInfo *cube_info,
2453 % const NodeInfo *node_info)
2455 % A description of each parameter follows.
2457 % o image: the image.
2459 % o cube_info: A pointer to the Cube structure.
2461 % o node_info: pointer to node in color cube tree that is to be pruned.
2464 static void PruneChild(const Image *image,CubeInfo *cube_info,
2465 const NodeInfo *node_info)
2477 Traverse any children.
2479 number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2480 for (i=0; i < (ssize_t) number_children; i++)
2481 if (node_info->child[i] != (NodeInfo *) NULL)
2482 PruneChild(image,cube_info,node_info->child[i]);
2484 Merge color statistics into parent.
2486 parent=node_info->parent;
2487 parent->number_unique+=node_info->number_unique;
2488 parent->total_color.red+=node_info->total_color.red;
2489 parent->total_color.green+=node_info->total_color.green;
2490 parent->total_color.blue+=node_info->total_color.blue;
2491 parent->total_color.alpha+=node_info->total_color.alpha;
2492 parent->child[node_info->id]=(NodeInfo *) NULL;
2497 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2501 + P r u n e L e v e l %
2505 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2507 % PruneLevel() deletes all nodes at the bottom level of the color tree merging
2508 % their color statistics into their parent node.
2510 % The format of the PruneLevel method is:
2512 % PruneLevel(const Image *image,CubeInfo *cube_info,
2513 % const NodeInfo *node_info)
2515 % A description of each parameter follows.
2517 % o image: the image.
2519 % o cube_info: A pointer to the Cube structure.
2521 % o node_info: pointer to node in color cube tree that is to be pruned.
2524 static void PruneLevel(const Image *image,CubeInfo *cube_info,
2525 const NodeInfo *node_info)
2534 Traverse any children.
2536 number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2537 for (i=0; i < (ssize_t) number_children; i++)
2538 if (node_info->child[i] != (NodeInfo *) NULL)
2539 PruneLevel(image,cube_info,node_info->child[i]);
2540 if (node_info->level == cube_info->depth)
2541 PruneChild(image,cube_info,node_info);
2545 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2549 + P r u n e T o C u b e D e p t h %
2553 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2555 % PruneToCubeDepth() deletes any nodes at a depth greater than
2556 % cube_info->depth while merging their color statistics into their parent
2559 % The format of the PruneToCubeDepth method is:
2561 % PruneToCubeDepth(const Image *image,CubeInfo *cube_info,
2562 % const NodeInfo *node_info)
2564 % A description of each parameter follows.
2566 % o cube_info: A pointer to the Cube structure.
2568 % o node_info: pointer to node in color cube tree that is to be pruned.
2571 static void PruneToCubeDepth(const Image *image,CubeInfo *cube_info,
2572 const NodeInfo *node_info)
2581 Traverse any children.
2583 number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2584 for (i=0; i < (ssize_t) number_children; i++)
2585 if (node_info->child[i] != (NodeInfo *) NULL)
2586 PruneToCubeDepth(image,cube_info,node_info->child[i]);
2587 if (node_info->level > cube_info->depth)
2588 PruneChild(image,cube_info,node_info);
2592 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2596 % Q u a n t i z e I m a g e %
2600 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2602 % QuantizeImage() analyzes the colors within a reference image and chooses a
2603 % fixed number of colors to represent the image. The goal of the algorithm
2604 % is to minimize the color difference between the input and output image while
2605 % minimizing the processing time.
2607 % The format of the QuantizeImage method is:
2609 % MagickBooleanType QuantizeImage(const QuantizeInfo *quantize_info,
2612 % A description of each parameter follows:
2614 % o quantize_info: Specifies a pointer to an QuantizeInfo structure.
2616 % o image: the image.
2619 MagickExport MagickBooleanType QuantizeImage(const QuantizeInfo *quantize_info,
2632 assert(quantize_info != (const QuantizeInfo *) NULL);
2633 assert(quantize_info->signature == MagickSignature);
2634 assert(image != (Image *) NULL);
2635 assert(image->signature == MagickSignature);
2636 if (image->debug != MagickFalse)
2637 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
2638 maximum_colors=quantize_info->number_colors;
2639 if (maximum_colors == 0)
2640 maximum_colors=MaxColormapSize;
2641 if (maximum_colors > MaxColormapSize)
2642 maximum_colors=MaxColormapSize;
2643 if ((IsImageGray(image,&image->exception) != MagickFalse) &&
2644 (image->matte == MagickFalse))
2645 (void) SetGrayscaleImage(image);
2646 if ((image->storage_class == PseudoClass) &&
2647 (image->colors <= maximum_colors))
2649 depth=quantize_info->tree_depth;
2656 Depth of color tree is: Log4(colormap size)+2.
2658 colors=maximum_colors;
2659 for (depth=1; colors != 0; depth++)
2661 if ((quantize_info->dither != MagickFalse) && (depth > 2))
2663 if ((image->matte != MagickFalse) && (depth > 5))
2667 Initialize color cube.
2669 cube_info=GetCubeInfo(quantize_info,depth,maximum_colors);
2670 if (cube_info == (CubeInfo *) NULL)
2671 ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
2673 status=ClassifyImageColors(cube_info,image,&image->exception);
2674 if (status != MagickFalse)
2677 Reduce the number of colors in the image.
2679 ReduceImageColors(image,cube_info);
2680 status=AssignImageColors(image,cube_info);
2682 DestroyCubeInfo(cube_info);
2687 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2691 % Q u a n t i z e I m a g e s %
2695 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2697 % QuantizeImages() analyzes the colors within a set of reference images and
2698 % chooses a fixed number of colors to represent the set. The goal of the
2699 % algorithm is to minimize the color difference between the input and output
2700 % images while minimizing the processing time.
2702 % The format of the QuantizeImages method is:
2704 % MagickBooleanType QuantizeImages(const QuantizeInfo *quantize_info,
2707 % A description of each parameter follows:
2709 % o quantize_info: Specifies a pointer to an QuantizeInfo structure.
2711 % o images: Specifies a pointer to a list of Image structures.
2714 MagickExport MagickBooleanType QuantizeImages(const QuantizeInfo *quantize_info,
2727 MagickProgressMonitor
2738 assert(quantize_info != (const QuantizeInfo *) NULL);
2739 assert(quantize_info->signature == MagickSignature);
2740 assert(images != (Image *) NULL);
2741 assert(images->signature == MagickSignature);
2742 if (images->debug != MagickFalse)
2743 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",images->filename);
2744 if (GetNextImageInList(images) == (Image *) NULL)
2747 Handle a single image with QuantizeImage.
2749 status=QuantizeImage(quantize_info,images);
2753 maximum_colors=quantize_info->number_colors;
2754 if (maximum_colors == 0)
2755 maximum_colors=MaxColormapSize;
2756 if (maximum_colors > MaxColormapSize)
2757 maximum_colors=MaxColormapSize;
2758 depth=quantize_info->tree_depth;
2765 Depth of color tree is: Log4(colormap size)+2.
2767 colors=maximum_colors;
2768 for (depth=1; colors != 0; depth++)
2770 if (quantize_info->dither != MagickFalse)
2774 Initialize color cube.
2776 cube_info=GetCubeInfo(quantize_info,depth,maximum_colors);
2777 if (cube_info == (CubeInfo *) NULL)
2779 (void) ThrowMagickException(&images->exception,GetMagickModule(),
2780 ResourceLimitError,"MemoryAllocationFailed","`%s'",images->filename);
2781 return(MagickFalse);
2783 number_images=GetImageListLength(images);
2785 for (i=0; image != (Image *) NULL; i++)
2787 progress_monitor=SetImageProgressMonitor(image,(MagickProgressMonitor) NULL,
2788 image->client_data);
2789 status=ClassifyImageColors(cube_info,image,&image->exception);
2790 if (status == MagickFalse)
2792 (void) SetImageProgressMonitor(image,progress_monitor,image->client_data);
2793 proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) i,
2795 if (proceed == MagickFalse)
2797 image=GetNextImageInList(image);
2799 if (status != MagickFalse)
2802 Reduce the number of colors in an image sequence.
2804 ReduceImageColors(images,cube_info);
2806 for (i=0; image != (Image *) NULL; i++)
2808 progress_monitor=SetImageProgressMonitor(image,(MagickProgressMonitor)
2809 NULL,image->client_data);
2810 status=AssignImageColors(image,cube_info);
2811 if (status == MagickFalse)
2813 (void) SetImageProgressMonitor(image,progress_monitor,
2814 image->client_data);
2815 proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) i,
2817 if (proceed == MagickFalse)
2819 image=GetNextImageInList(image);
2822 DestroyCubeInfo(cube_info);
2827 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2835 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2837 % Reduce() traverses the color cube tree and prunes any node whose
2838 % quantization error falls below a particular threshold.
2840 % The format of the Reduce method is:
2842 % Reduce(const Image *image,CubeInfo *cube_info,const NodeInfo *node_info)
2844 % A description of each parameter follows.
2846 % o image: the image.
2848 % o cube_info: A pointer to the Cube structure.
2850 % o node_info: pointer to node in color cube tree that is to be pruned.
2853 static void Reduce(const Image *image,CubeInfo *cube_info,
2854 const NodeInfo *node_info)
2863 Traverse any children.
2865 number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2866 for (i=0; i < (ssize_t) number_children; i++)
2867 if (node_info->child[i] != (NodeInfo *) NULL)
2868 Reduce(image,cube_info,node_info->child[i]);
2869 if (node_info->quantize_error <= cube_info->pruning_threshold)
2870 PruneChild(image,cube_info,node_info);
2874 Find minimum pruning threshold.
2876 if (node_info->number_unique > 0)
2877 cube_info->colors++;
2878 if (node_info->quantize_error < cube_info->next_threshold)
2879 cube_info->next_threshold=node_info->quantize_error;
2884 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2888 + R e d u c e I m a g e C o l o r s %
2892 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2894 % ReduceImageColors() repeatedly prunes the tree until the number of nodes
2895 % with n2 > 0 is less than or equal to the maximum number of colors allowed
2896 % in the output image. On any given iteration over the tree, it selects
2897 % those nodes whose E value is minimal for pruning and merges their
2898 % color statistics upward. It uses a pruning threshold, Ep, to govern
2899 % node selection as follows:
2902 % while number of nodes with (n2 > 0) > required maximum number of colors
2903 % prune all nodes such that E <= Ep
2904 % Set Ep to minimum E in remaining nodes
2906 % This has the effect of minimizing any quantization error when merging
2907 % two nodes together.
2909 % When a node to be pruned has offspring, the pruning procedure invokes
2910 % itself recursively in order to prune the tree from the leaves upward.
2911 % n2, Sr, Sg, and Sb in a node being pruned are always added to the
2912 % corresponding data in that node's parent. This retains the pruned
2913 % node's color characteristics for later averaging.
2915 % For each node, n2 pixels exist for which that node represents the
2916 % smallest volume in RGB space containing those pixel's colors. When n2
2917 % > 0 the node will uniquely define a color in the output image. At the
2918 % beginning of reduction, n2 = 0 for all nodes except a the leaves of
2919 % the tree which represent colors present in the input image.
2921 % The other pixel count, n1, indicates the total number of colors
2922 % within the cubic volume which the node represents. This includes n1 -
2923 % n2 pixels whose colors should be defined by nodes at a lower level in
2926 % The format of the ReduceImageColors method is:
2928 % ReduceImageColors(const Image *image,CubeInfo *cube_info)
2930 % A description of each parameter follows.
2932 % o image: the image.
2934 % o cube_info: A pointer to the Cube structure.
2937 static void ReduceImageColors(const Image *image,CubeInfo *cube_info)
2939 #define ReduceImageTag "Reduce/Image"
2950 cube_info->next_threshold=0.0;
2951 for (span=cube_info->colors; cube_info->colors > cube_info->maximum_colors; )
2953 cube_info->pruning_threshold=cube_info->next_threshold;
2954 cube_info->next_threshold=cube_info->root->quantize_error-1;
2955 cube_info->colors=0;
2956 Reduce(image,cube_info,cube_info->root);
2957 offset=(MagickOffsetType) span-cube_info->colors;
2958 proceed=SetImageProgress(image,ReduceImageTag,offset,span-
2959 cube_info->maximum_colors+1);
2960 if (proceed == MagickFalse)
2966 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2970 % R e m a p I m a g e %
2974 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2976 % RemapImage() replaces the colors of an image with the closest color from
2977 % a reference image.
2979 % The format of the RemapImage method is:
2981 % MagickBooleanType RemapImage(const QuantizeInfo *quantize_info,
2982 % Image *image,const Image *remap_image)
2984 % A description of each parameter follows:
2986 % o quantize_info: Specifies a pointer to an QuantizeInfo structure.
2988 % o image: the image.
2990 % o remap_image: the reference image.
2993 MagickExport MagickBooleanType RemapImage(const QuantizeInfo *quantize_info,
2994 Image *image,const Image *remap_image)
3003 Initialize color cube.
3005 assert(image != (Image *) NULL);
3006 assert(image->signature == MagickSignature);
3007 if (image->debug != MagickFalse)
3008 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
3009 assert(remap_image != (Image *) NULL);
3010 assert(remap_image->signature == MagickSignature);
3011 cube_info=GetCubeInfo(quantize_info,MaxTreeDepth,
3012 quantize_info->number_colors);
3013 if (cube_info == (CubeInfo *) NULL)
3014 ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3016 status=ClassifyImageColors(cube_info,remap_image,&image->exception);
3017 if (status != MagickFalse)
3020 Classify image colors from the reference image.
3022 cube_info->quantize_info->number_colors=cube_info->colors;
3023 status=AssignImageColors(image,cube_info);
3025 DestroyCubeInfo(cube_info);
3030 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3034 % R e m a p I m a g e s %
3038 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3040 % RemapImages() replaces the colors of a sequence of images with the
3041 % closest color from a reference image.
3043 % The format of the RemapImage method is:
3045 % MagickBooleanType RemapImages(const QuantizeInfo *quantize_info,
3046 % Image *images,Image *remap_image)
3048 % A description of each parameter follows:
3050 % o quantize_info: Specifies a pointer to an QuantizeInfo structure.
3052 % o images: the image sequence.
3054 % o remap_image: the reference image.
3057 MagickExport MagickBooleanType RemapImages(const QuantizeInfo *quantize_info,
3058 Image *images,const Image *remap_image)
3069 assert(images != (Image *) NULL);
3070 assert(images->signature == MagickSignature);
3071 if (images->debug != MagickFalse)
3072 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",images->filename);
3074 if (remap_image == (Image *) NULL)
3077 Create a global colormap for an image sequence.
3079 status=QuantizeImages(quantize_info,images);
3083 Classify image colors from the reference image.
3085 cube_info=GetCubeInfo(quantize_info,MaxTreeDepth,
3086 quantize_info->number_colors);
3087 if (cube_info == (CubeInfo *) NULL)
3088 ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3090 status=ClassifyImageColors(cube_info,remap_image,&image->exception);
3091 if (status != MagickFalse)
3094 Classify image colors from the reference image.
3096 cube_info->quantize_info->number_colors=cube_info->colors;
3098 for ( ; image != (Image *) NULL; image=GetNextImageInList(image))
3100 status=AssignImageColors(image,cube_info);
3101 if (status == MagickFalse)
3105 DestroyCubeInfo(cube_info);
3110 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3114 % S e t G r a y s c a l e I m a g e %
3118 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3120 % SetGrayscaleImage() converts an image to a PseudoClass grayscale image.
3122 % The format of the SetGrayscaleImage method is:
3124 % MagickBooleanType SetGrayscaleImage(Image *image)
3126 % A description of each parameter follows:
3128 % o image: The image.
3132 #if defined(__cplusplus) || defined(c_plusplus)
3136 static int IntensityCompare(const void *x,const void *y)
3145 color_1=(PixelPacket *) x;
3146 color_2=(PixelPacket *) y;
3147 intensity=GetPixelPacketIntensity(color_1)-(ssize_t)
3148 GetPixelPacketIntensity(color_2);
3149 return((int) intensity);
3152 #if defined(__cplusplus) || defined(c_plusplus)
3156 static MagickBooleanType SetGrayscaleImage(Image *image)
3178 assert(image != (Image *) NULL);
3179 assert(image->signature == MagickSignature);
3180 if (image->type != GrayscaleType)
3181 (void) TransformImageColorspace(image,GRAYColorspace);
3182 colormap_index=(ssize_t *) AcquireQuantumMemory(MaxMap+1,
3183 sizeof(*colormap_index));
3184 if (colormap_index == (ssize_t *) NULL)
3185 ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3187 if (image->storage_class != PseudoClass)
3192 for (i=0; i <= (ssize_t) MaxMap; i++)
3193 colormap_index[i]=(-1);
3194 if (AcquireImageColormap(image,MaxMap+1) == MagickFalse)
3195 ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3199 exception=(&image->exception);
3200 image_view=AcquireCacheView(image);
3201 #if defined(MAGICKCORE_OPENMP_SUPPORT)
3202 #pragma omp parallel for schedule(dynamic,4) shared(status)
3204 for (y=0; y < (ssize_t) image->rows; y++)
3212 if (status == MagickFalse)
3214 q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,
3216 if (q == (const Quantum *) NULL)
3221 for (x=0; x < (ssize_t) image->columns; x++)
3226 intensity=ScaleQuantumToMap(GetPixelRed(image,q));
3227 if (colormap_index[intensity] < 0)
3229 #if defined(MAGICKCORE_OPENMP_SUPPORT)
3230 #pragma omp critical (MagickCore_SetGrayscaleImage)
3232 if (colormap_index[intensity] < 0)
3234 colormap_index[intensity]=(ssize_t) image->colors;
3235 image->colormap[image->colors].red=GetPixelRed(image,q);
3236 image->colormap[image->colors].green=GetPixelGreen(image,q);
3237 image->colormap[image->colors].blue=GetPixelBlue(image,q);
3241 SetPixelIndex(image,(Quantum)
3242 colormap_index[intensity],q);
3243 q+=GetPixelChannels(image);
3245 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
3248 image_view=DestroyCacheView(image_view);
3250 for (i=0; i < (ssize_t) image->colors; i++)
3251 image->colormap[i].alpha=(unsigned short) i;
3252 qsort((void *) image->colormap,image->colors,sizeof(PixelPacket),
3254 colormap=(PixelPacket *) AcquireQuantumMemory(image->colors,
3256 if (colormap == (PixelPacket *) NULL)
3257 ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3260 colormap[j]=image->colormap[0];
3261 for (i=0; i < (ssize_t) image->colors; i++)
3263 if (IsPixelPacketEquivalent(&colormap[j],&image->colormap[i]) == MagickFalse)
3266 colormap[j]=image->colormap[i];
3268 colormap_index[(ssize_t) image->colormap[i].alpha]=j;
3270 image->colors=(size_t) (j+1);
3271 image->colormap=(PixelPacket *) RelinquishMagickMemory(image->colormap);
3272 image->colormap=colormap;
3274 exception=(&image->exception);
3275 image_view=AcquireCacheView(image);
3276 #if defined(MAGICKCORE_OPENMP_SUPPORT)
3277 #pragma omp parallel for schedule(dynamic,4) shared(status)
3279 for (y=0; y < (ssize_t) image->rows; y++)
3287 if (status == MagickFalse)
3289 q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
3290 if (q == (const Quantum *) NULL)
3295 for (x=0; x < (ssize_t) image->columns; x++)
3297 SetPixelIndex(image,(Quantum) colormap_index[ScaleQuantumToMap(
3298 GetPixelIndex(image,q))],q);
3299 q+=GetPixelChannels(image);
3301 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
3304 image_view=DestroyCacheView(image_view);
3305 colormap_index=(ssize_t *) RelinquishMagickMemory(colormap_index);
3306 image->type=GrayscaleType;
3307 if (IsImageMonochrome(image,&image->exception) != MagickFalse)
3308 image->type=BilevelType;