granicus.if.org Git - imagemagick/blob - MagickCore/quantize.c

   1 /*
   2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   3 %                                                                             %
   4 %                                                                             %
   5 %                                                                             %
   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                %
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  11 %                                                                             %
  12 %                                                                             %
  13 %    MagickCore Methods to Reduce the Number of Unique Colors in an Image     %
  14 %                                                                             %
  15 %                           Software Design                                   %
  16 %                             John Cristy                                     %
  17 %                              July 1992                                      %
  18 %                                                                             %
  19 %                                                                             %
  20 %  Copyright 1999-2012 ImageMagick Studio LLC, a non-profit organization      %
  21 %  dedicated to making software imaging solutions freely available.           %
  22 %                                                                             %
  23 %  You may not use this file except in compliance with the License.  You may  %
  24 %  obtain a copy of the License at                                            %
  25 %                                                                             %
  26 %    http://www.imagemagick.org/script/license.php                            %
  27 %                                                                             %
  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.                                             %
  33 %                                                                             %
  34 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  35 %
  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.
  43 %
  44 %  A reduction of colors in an image is also desirable for image
  45 %  transmission and real-time animation.
  46 %
  47 %  QuantizeImage() takes a standard RGB or monochrome images and quantizes
  48 %  them down to some fixed number of colors.
  49 %
  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).
  54 %
  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 =
  60 %  255.
  61 %
  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
  66 %  the origin.
  67 %
  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.
  73 %
  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).
  82 %
  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 +
  91 %  sum(i=1, k, 8k).
  92 %
  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)).
  98 %
  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
 103 %  such node:
 104 %
 105 %    n1: Number of pixels whose color is contained in the RGB cube which
 106 %    this node represents;
 107 %
 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.
 111 %
 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.
 116 %
 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.
 120 %
 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:
 127 %
 128 %    Ep = 0
 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
 132 %
 133 %  This has the effect of minimizing any quantization error when merging
 134 %  two nodes together.
 135 %
 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.
 141 %
 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.
 147 %
 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
 151 %  tree.
 152 %
 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.
 158 %
 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.
 164 %
 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.
 169 %
 170 %  This method is based on a similar algorithm written by Paul Raveling.
 171 %
 172 */
 173 \f
 174 /*
 175   Include declarations.
 176 */
 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"
 204 \f
 205 /*
 206   Define declarations.
 207 */
 208 #if !defined(__APPLE__) && !defined(TARGET_OS_IPHONE)
 209 #define CacheShift  2
 210 #else
 211 #define CacheShift  3
 212 #endif
 213 #define ErrorQueueLength  16
 214 #define MaxNodes  266817
 215 #define MaxTreeDepth  8
 216 #define NodesInAList  1920
 217 \f
 218 /*
 219   Typdef declarations.
 220 */
 221 typedef struct _RealPixelInfo
 222 {
 223   MagickRealType
 224     red,
 225     green,
 226     blue,
 227     alpha;
 228 } RealPixelInfo;
 229
 230 typedef struct _NodeInfo
 231 {
 232   struct _NodeInfo
 233     *parent,
 234     *child[16];
 235
 236   MagickSizeType
 237     number_unique;
 238
 239   RealPixelInfo
 240     total_color;
 241
 242   MagickRealType
 243     quantize_error;
 244
 245   size_t
 246     color_number,
 247     id,
 248     level;
 249 } NodeInfo;
 250
 251 typedef struct _Nodes
 252 {
 253   NodeInfo
 254     *nodes;
 255
 256   struct _Nodes
 257     *next;
 258 } Nodes;
 259
 260 typedef struct _CubeInfo
 261 {
 262   NodeInfo
 263     *root;
 264
 265   size_t
 266     colors,
 267     maximum_colors;
 268
 269   ssize_t
 270     transparent_index;
 271
 272   MagickSizeType
 273     transparent_pixels;
 274
 275   RealPixelInfo
 276     target;
 277
 278   MagickRealType
 279     distance,
 280     pruning_threshold,
 281     next_threshold;
 282
 283   size_t
 284     nodes,
 285     free_nodes,
 286     color_number;
 287
 288   NodeInfo
 289     *next_node;
 290
 291   Nodes
 292     *node_queue;
 293
 294   ssize_t
 295     *cache;
 296
 297   RealPixelInfo
 298     error[ErrorQueueLength];
 299
 300   MagickRealType
 301     weights[ErrorQueueLength];
 302
 303   QuantizeInfo
 304     *quantize_info;
 305
 306   MagickBooleanType
 307     associate_alpha;
 308
 309   ssize_t
 310     x,
 311     y;
 312
 313   size_t
 314     depth;
 315
 316   MagickOffsetType
 317     offset;
 318
 319   MagickSizeType
 320     span;
 321 } CubeInfo;
 322 \f
 323 /*
 324   Method prototypes.
 325 */
 326 static CubeInfo
 327   *GetCubeInfo(const QuantizeInfo *,const size_t,const size_t);
 328
 329 static NodeInfo
 330   *GetNodeInfo(CubeInfo *,const size_t,const size_t,NodeInfo *);
 331
 332 static MagickBooleanType
 333   AssignImageColors(Image *,CubeInfo *,ExceptionInfo *),
 334   ClassifyImageColors(CubeInfo *,const Image *,ExceptionInfo *),
 335   DitherImage(Image *,CubeInfo *,ExceptionInfo *),
 336   SetGrayscaleImage(Image *,ExceptionInfo *);
 337
 338 static size_t
 339   DefineImageColormap(Image *,CubeInfo *,NodeInfo *);
 340
 341 static void
 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 *);
 347 \f
 348 /*
 349 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 350 %                                                                             %
 351 %                                                                             %
 352 %                                                                             %
 353 %   A c q u i r e Q u a n t i z e I n f o                                     %
 354 %                                                                             %
 355 %                                                                             %
 356 %                                                                             %
 357 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 358 %
 359 %  AcquireQuantizeInfo() allocates the QuantizeInfo structure.
 360 %
 361 %  The format of the AcquireQuantizeInfo method is:
 362 %
 363 %      QuantizeInfo *AcquireQuantizeInfo(const ImageInfo *image_info)
 364 %
 365 %  A description of each parameter follows:
 366 %
 367 %    o image_info: the image info.
 368 %
 369 */
 370 MagickExport QuantizeInfo *AcquireQuantizeInfo(const ImageInfo *image_info)
 371 {
 372   QuantizeInfo
 373     *quantize_info;
 374
 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)
 380     {
 381       const char
 382         *option;
 383
 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;
 391     }
 392   return(quantize_info);
 393 }
 394 \f
 395 /*
 396 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 397 %                                                                             %
 398 %                                                                             %
 399 %                                                                             %
 400 +   A s s i g n I m a g e C o l o r s                                         %
 401 %                                                                             %
 402 %                                                                             %
 403 %                                                                             %
 404 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 405 %
 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.
 411 %
 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.
 417 %
 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.
 422 %
 423 %  The format of the AssignImageColors() method is:
 424 %
 425 %      MagickBooleanType AssignImageColors(Image *image,CubeInfo *cube_info)
 426 %
 427 %  A description of each parameter follows.
 428 %
 429 %    o image: the image.
 430 %
 431 %    o cube_info: A pointer to the Cube structure.
 432 %
 433 */
 434
 435 static inline void AssociateAlphaPixel(const Image *image,
 436   const CubeInfo *cube_info,const Quantum *pixel,RealPixelInfo *alpha_pixel)
 437 {
 438   MagickRealType
 439     alpha;
 440
 441   if ((cube_info->associate_alpha == MagickFalse) ||
 442       (GetPixelAlpha(image,pixel)== OpaqueAlpha))
 443     {
 444       alpha_pixel->red=(MagickRealType) GetPixelRed(image,pixel);
 445       alpha_pixel->green=(MagickRealType) GetPixelGreen(image,pixel);
 446       alpha_pixel->blue=(MagickRealType) GetPixelBlue(image,pixel);
 447       alpha_pixel->alpha=(MagickRealType) GetPixelAlpha(image,pixel);
 448       return;
 449     }
 450   alpha=(MagickRealType) (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=(MagickRealType) GetPixelAlpha(image,pixel);
 455 }
 456
 457 static inline void AssociateAlphaPixelInfo(const Image *image,
 458   const CubeInfo *cube_info,const PixelInfo *pixel,
 459   RealPixelInfo *alpha_pixel)
 460 {
 461   MagickRealType
 462     alpha;
 463
 464   if ((cube_info->associate_alpha == MagickFalse) ||
 465       (pixel->alpha == OpaqueAlpha))
 466     {
 467       alpha_pixel->red=(MagickRealType) pixel->red;
 468       alpha_pixel->green=(MagickRealType) pixel->green;
 469       alpha_pixel->blue=(MagickRealType) pixel->blue;
 470       alpha_pixel->alpha=(MagickRealType) pixel->alpha;
 471       return;
 472     }
 473   alpha=(MagickRealType) (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=(MagickRealType) pixel->alpha;
 478 }
 479
 480 static inline Quantum ClampToUnsignedQuantum(const MagickRealType value)
 481 {
 482   if (value <= 0.0)
 483     return((Quantum) 0);
 484   if (value >= QuantumRange)
 485     return(QuantumRange);
 486   return((Quantum) (value+0.5));
 487 }
 488
 489 static inline size_t ColorToNodeId(const CubeInfo *cube_info,
 490   const RealPixelInfo *pixel,size_t index)
 491 {
 492   size_t
 493     id;
 494
 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;
 500   return(id);
 501 }
 502
 503 static MagickBooleanType AssignImageColors(Image *image,CubeInfo *cube_info,
 504   ExceptionInfo *exception)
 505 {
 506 #define AssignImageTag  "Assign/Image"
 507
 508   ssize_t
 509     y;
 510
 511   /*
 512     Allocate image colormap.
 513   */
 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);
 518   else
 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",
 523       image->filename);
 524   image->colors=0;
 525   cube_info->transparent_pixels=0;
 526   cube_info->transparent_index=(-1);
 527   (void) DefineImageColormap(image,cube_info,cube_info->root);
 528   /*
 529     Create a reduced color image.
 530   */
 531   if ((cube_info->quantize_info->dither_method != NoDitherMethod) &&
 532       (cube_info->quantize_info->dither_method != NoDitherMethod))
 533     (void) DitherImage(image,cube_info,exception);
 534   else
 535     {
 536       CacheView
 537         *image_view;
 538
 539       MagickBooleanType
 540         status;
 541
 542       status=MagickTrue;
 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)
 547 #endif
 548       for (y=0; y < (ssize_t) image->rows; y++)
 549       {
 550         CubeInfo
 551           cube;
 552
 553         register Quantum
 554           *restrict q;
 555
 556         register ssize_t
 557           x;
 558
 559         ssize_t
 560           count;
 561
 562         if (status == MagickFalse)
 563           continue;
 564         q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,
 565           exception);
 566         if (q == (Quantum *) NULL)
 567           {
 568             status=MagickFalse;
 569             continue;
 570           }
 571         cube=(*cube_info);
 572         for (x=0; x < (ssize_t) image->columns; x+=count)
 573         {
 574           RealPixelInfo
 575             pixel;
 576
 577           register const NodeInfo
 578             *node_info;
 579
 580           register ssize_t
 581             i;
 582
 583           size_t
 584             id,
 585             index;
 586
 587           /*
 588             Identify the deepest node containing the pixel's color.
 589           */
 590           for (count=1; (x+count) < (ssize_t) image->columns; count++)
 591           {
 592             PixelInfo
 593               packet;
 594
 595             GetPixelInfoPixel(image,q+count*GetPixelChannels(image),&packet);
 596             if (IsPixelEquivalent(image,q,&packet) == MagickFalse)
 597               break;
 598           }
 599           AssociateAlphaPixel(image,&cube,q,&pixel);
 600           node_info=cube.root;
 601           for (index=MaxTreeDepth-1; (ssize_t) index > 0; index--)
 602           {
 603             id=ColorToNodeId(&cube,&pixel,index);
 604             if (node_info->child[id] == (NodeInfo *) NULL)
 605               break;
 606             node_info=node_info->child[id];
 607           }
 608           /*
 609             Find closest color among siblings and their children.
 610           */
 611           cube.target=pixel;
 612           cube.distance=(MagickRealType) (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++)
 617           {
 618             if (image->storage_class == PseudoClass)
 619               SetPixelIndex(image,(Quantum) index,q);
 620             if (cube.quantize_info->measure_error == MagickFalse)
 621               {
 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);
 631               }
 632             q+=GetPixelChannels(image);
 633           }
 634         }
 635         if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
 636           status=MagickFalse;
 637         if (image->progress_monitor != (MagickProgressMonitor) NULL)
 638           {
 639             MagickBooleanType
 640               proceed;
 641
 642 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 643             #pragma omp critical (MagickCore_AssignImageColors)
 644 #endif
 645             proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) y,
 646               image->rows);
 647             if (proceed == MagickFalse)
 648               status=MagickFalse;
 649           }
 650       }
 651       image_view=DestroyCacheView(image_view);
 652     }
 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))
 657     {
 658       double
 659         intensity;
 660
 661       register PixelInfo
 662         *restrict q;
 663
 664       register ssize_t
 665         i;
 666
 667       /*
 668         Monochrome image.
 669       */
 670       q=image->colormap;
 671       for (i=0; i < (ssize_t) image->colors; i++)
 672       {
 673         intensity=(double) ((MagickRealType) GetPixelInfoIntensity(q) <
 674           ((MagickRealType) QuantumRange/2.0) ? 0 : QuantumRange);
 675         q->red=intensity;
 676         q->green=intensity;
 677         q->blue=intensity;
 678         q++;
 679       }
 680     }
 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);
 685   return(MagickTrue);
 686 }
 687 \f
 688 /*
 689 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 690 %                                                                             %
 691 %                                                                             %
 692 %                                                                             %
 693 +   C l a s s i f y I m a g e C o l o r s                                     %
 694 %                                                                             %
 695 %                                                                             %
 696 %                                                                             %
 697 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 698 %
 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
 707 %  1 + sum(i=1,k,8k).
 708 %
 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)).
 714 %
 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:
 719 %
 720 %    n1 : Number of pixels whose color is contained in the RGB cube
 721 %    which this node represents;
 722 %
 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.
 726 %
 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.
 731 %
 732 %    E: the distance squared in RGB space between each pixel contained
 733 %    within a node and the nodes' center.  This represents the quantization
 734 %    error for a node.
 735 %
 736 %  The format of the ClassifyImageColors() method is:
 737 %
 738 %      MagickBooleanType ClassifyImageColors(CubeInfo *cube_info,
 739 %        const Image *image,ExceptionInfo *exception)
 740 %
 741 %  A description of each parameter follows.
 742 %
 743 %    o cube_info: A pointer to the Cube structure.
 744 %
 745 %    o image: the image.
 746 %
 747 */
 748
 749 static inline void SetAssociatedAlpha(const Image *image,CubeInfo *cube_info)
 750 {
 751   MagickBooleanType
 752     associate_alpha;
 753
 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;
 761 }
 762
 763 static MagickBooleanType ClassifyImageColors(CubeInfo *cube_info,
 764   const Image *image,ExceptionInfo *exception)
 765 {
 766 #define ClassifyImageTag  "Classify/Image"
 767
 768   CacheView
 769     *image_view;
 770
 771   MagickBooleanType
 772     proceed;
 773
 774   MagickRealType
 775     bisect;
 776
 777   NodeInfo
 778     *node_info;
 779
 780   RealPixelInfo
 781     error,
 782     mid,
 783     midpoint,
 784     pixel;
 785
 786   size_t
 787     count,
 788     id,
 789     index,
 790     level;
 791
 792   ssize_t
 793     y;
 794
 795   /*
 796     Classify the first cube_info->maximum_colors colors to a tree depth of 8.
 797   */
 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);
 803   else
 804     if (IssRGBCompatibleColorspace(image->colorspace) == MagickFalse)
 805       (void) TransformImageColorspace((Image *) image,sRGBColorspace,exception);
 806   midpoint.red=(MagickRealType) QuantumRange/2.0;
 807   midpoint.green=(MagickRealType) QuantumRange/2.0;
 808   midpoint.blue=(MagickRealType) QuantumRange/2.0;
 809   midpoint.alpha=(MagickRealType) QuantumRange/2.0;
 810   error.alpha=0.0;
 811   image_view=AcquireVirtualCacheView(image,exception);
 812   for (y=0; y < (ssize_t) image->rows; y++)
 813   {
 814     register const Quantum
 815       *restrict p;
 816
 817     register ssize_t
 818       x;
 819
 820     p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
 821     if (p == (const Quantum *) NULL)
 822       break;
 823     if (cube_info->nodes > MaxNodes)
 824       {
 825         /*
 826           Prune one level if the color tree is too large.
 827         */
 828         PruneLevel(image,cube_info,cube_info->root);
 829         cube_info->depth--;
 830       }
 831     for (x=0; x < (ssize_t) image->columns; x+=(ssize_t) count)
 832     {
 833       /*
 834         Start at the root and descend the color cube tree.
 835       */
 836       for (count=1; (x+(ssize_t) count) < (ssize_t) image->columns; count++)
 837       {
 838         PixelInfo
 839           packet;
 840
 841         GetPixelInfoPixel(image,p+count*GetPixelChannels(image),&packet);
 842         if (IsPixelEquivalent(image,p,&packet) == MagickFalse)
 843           break;
 844       }
 845       AssociateAlphaPixel(image,cube_info,p,&pixel);
 846       index=MaxTreeDepth-1;
 847       bisect=((MagickRealType) QuantumRange+1.0)/2.0;
 848       mid=midpoint;
 849       node_info=cube_info->root;
 850       for (level=1; level <= MaxTreeDepth; level++)
 851       {
 852         bisect*=0.5;
 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)
 859           {
 860             /*
 861               Set colors of new node to contain pixel.
 862             */
 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'",
 867                 image->filename);
 868             if (level == MaxTreeDepth)
 869               cube_info->colors++;
 870           }
 871         /*
 872           Approximate the quantization error represented by this node.
 873         */
 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;
 884         index--;
 885       }
 886       /*
 887         Sum RGB for this leaf for later derivation of the mean cube color.
 888       */
 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);
 896     }
 897     if (cube_info->colors > cube_info->maximum_colors)
 898       {
 899         PruneToCubeDepth(image,cube_info,cube_info->root);
 900         break;
 901       }
 902     proceed=SetImageProgress(image,ClassifyImageTag,(MagickOffsetType) y,
 903       image->rows);
 904     if (proceed == MagickFalse)
 905       break;
 906   }
 907   for (y++; y < (ssize_t) image->rows; y++)
 908   {
 909     register const Quantum
 910       *restrict p;
 911
 912     register ssize_t
 913       x;
 914
 915     p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
 916     if (p == (const Quantum *) NULL)
 917       break;
 918     if (cube_info->nodes > MaxNodes)
 919       {
 920         /*
 921           Prune one level if the color tree is too large.
 922         */
 923         PruneLevel(image,cube_info,cube_info->root);
 924         cube_info->depth--;
 925       }
 926     for (x=0; x < (ssize_t) image->columns; x+=(ssize_t) count)
 927     {
 928       /*
 929         Start at the root and descend the color cube tree.
 930       */
 931       for (count=1; (x+(ssize_t) count) < (ssize_t) image->columns; count++)
 932       {
 933         PixelInfo
 934           packet;
 935
 936         GetPixelInfoPixel(image,p+count*GetPixelChannels(image),&packet);
 937         if (IsPixelEquivalent(image,p,&packet) == MagickFalse)
 938           break;
 939       }
 940       AssociateAlphaPixel(image,cube_info,p,&pixel);
 941       index=MaxTreeDepth-1;
 942       bisect=((MagickRealType) QuantumRange+1.0)/2.0;
 943       mid=midpoint;
 944       node_info=cube_info->root;
 945       for (level=1; level <= cube_info->depth; level++)
 946       {
 947         bisect*=0.5;
 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)
 954           {
 955             /*
 956               Set colors of new node to contain pixel.
 957             */
 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",
 962                 image->filename);
 963             if (level == cube_info->depth)
 964               cube_info->colors++;
 965           }
 966         /*
 967           Approximate the quantization error represented by this node.
 968         */
 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;
 979         index--;
 980       }
 981       /*
 982         Sum RGB for this leaf for later derivation of the mean cube color.
 983       */
 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);
 991     }
 992     proceed=SetImageProgress(image,ClassifyImageTag,(MagickOffsetType) y,
 993       image->rows);
 994     if (proceed == MagickFalse)
 995       break;
 996   }
 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);
1001   return(MagickTrue);
1002 }
1003 \f
1004 /*
1005 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1006 %                                                                             %
1007 %                                                                             %
1008 %                                                                             %
1009 %   C l o n e Q u a n t i z e I n f o                                         %
1010 %                                                                             %
1011 %                                                                             %
1012 %                                                                             %
1013 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1014 %
1015 %  CloneQuantizeInfo() makes a duplicate of the given quantize info structure,
1016 %  or if quantize info is NULL, a new one.
1017 %
1018 %  The format of the CloneQuantizeInfo method is:
1019 %
1020 %      QuantizeInfo *CloneQuantizeInfo(const QuantizeInfo *quantize_info)
1021 %
1022 %  A description of each parameter follows:
1023 %
1024 %    o clone_info: Method CloneQuantizeInfo returns a duplicate of the given
1025 %      quantize info, or if image info is NULL a new one.
1026 %
1027 %    o quantize_info: a structure of type info.
1028 %
1029 */
1030 MagickExport QuantizeInfo *CloneQuantizeInfo(const QuantizeInfo *quantize_info)
1031 {
1032   QuantizeInfo
1033     *clone_info;
1034
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)
1040     return(clone_info);
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;
1046   return(clone_info);
1047 }
1048 \f
1049 /*
1050 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1051 %                                                                             %
1052 %                                                                             %
1053 %                                                                             %
1054 +   C l o s e s t C o l o r                                                   %
1055 %                                                                             %
1056 %                                                                             %
1057 %                                                                             %
1058 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1059 %
1060 %  ClosestColor() traverses the color cube tree at a particular node and
1061 %  determines which colormap entry best represents the input color.
1062 %
1063 %  The format of the ClosestColor method is:
1064 %
1065 %      void ClosestColor(const Image *image,CubeInfo *cube_info,
1066 %        const NodeInfo *node_info)
1067 %
1068 %  A description of each parameter follows.
1069 %
1070 %    o image: the image.
1071 %
1072 %    o cube_info: A pointer to the Cube structure.
1073 %
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.
1076 %
1077 */
1078 static void ClosestColor(const Image *image,CubeInfo *cube_info,
1079   const NodeInfo *node_info)
1080 {
1081   register ssize_t
1082     i;
1083
1084   size_t
1085     number_children;
1086
1087   /*
1088     Traverse any children.
1089   */
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)
1095     {
1096       MagickRealType
1097         pixel;
1098
1099       register MagickRealType
1100         alpha,
1101         beta,
1102         distance;
1103
1104       register PixelInfo
1105         *restrict p;
1106
1107       register RealPixelInfo
1108         *restrict q;
1109
1110       /*
1111         Determine if this color is "closest".
1112       */
1113       p=image->colormap+node_info->color_number;
1114       q=(&cube_info->target);
1115       alpha=1.0;
1116       beta=1.0;
1117       if (cube_info->associate_alpha != MagickFalse)
1118         {
1119           alpha=(MagickRealType) (QuantumScale*p->alpha);
1120           beta=(MagickRealType) (QuantumScale*q->alpha);
1121         }
1122       pixel=alpha*p->red-beta*q->red;
1123       distance=pixel*pixel;
1124       if (distance <= cube_info->distance)
1125         {
1126           pixel=alpha*p->green-beta*q->green;
1127           distance+=pixel*pixel;
1128           if (distance <= cube_info->distance)
1129             {
1130               pixel=alpha*p->blue-beta*q->blue;
1131               distance+=pixel*pixel;
1132               if (distance <= cube_info->distance)
1133                 {
1134                   pixel=alpha-beta;
1135                   distance+=pixel*pixel;
1136                   if (distance <= cube_info->distance)
1137                     {
1138                       cube_info->distance=distance;
1139                       cube_info->color_number=node_info->color_number;
1140                     }
1141                 }
1142             }
1143         }
1144     }
1145 }
1146 \f
1147 /*
1148 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1149 %                                                                             %
1150 %                                                                             %
1151 %                                                                             %
1152 %   C o m p r e s s I m a g e C o l o r m a p                                 %
1153 %                                                                             %
1154 %                                                                             %
1155 %                                                                             %
1156 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1157 %
1158 %  CompressImageColormap() compresses an image colormap by removing any
1159 %  duplicate or unused color entries.
1160 %
1161 %  The format of the CompressImageColormap method is:
1162 %
1163 %      MagickBooleanType CompressImageColormap(Image *image,
1164 %        ExceptionInfo *exception)
1165 %
1166 %  A description of each parameter follows:
1167 %
1168 %    o image: the image.
1169 %
1170 %    o exception: return any errors or warnings in this structure.
1171 %
1172 */
1173 MagickExport MagickBooleanType CompressImageColormap(Image *image,
1174   ExceptionInfo *exception)
1175 {
1176   QuantizeInfo
1177     quantize_info;
1178
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));
1189 }
1190 \f
1191 /*
1192 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1193 %                                                                             %
1194 %                                                                             %
1195 %                                                                             %
1196 +   D e f i n e I m a g e C o l o r m a p                                     %
1197 %                                                                             %
1198 %                                                                             %
1199 %                                                                             %
1200 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1201 %
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.
1206 %
1207 %  The format of the DefineImageColormap method is:
1208 %
1209 %      size_t DefineImageColormap(Image *image,CubeInfo *cube_info,
1210 %        NodeInfo *node_info)
1211 %
1212 %  A description of each parameter follows.
1213 %
1214 %    o image: the image.
1215 %
1216 %    o cube_info: A pointer to the Cube structure.
1217 %
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.
1220 %
1221 */
1222 static size_t DefineImageColormap(Image *image,CubeInfo *cube_info,
1223   NodeInfo *node_info)
1224 {
1225   register ssize_t
1226     i;
1227
1228   size_t
1229     number_children;
1230
1231   /*
1232     Traverse any children.
1233   */
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)
1239     {
1240       register MagickRealType
1241         alpha;
1242
1243       register PixelInfo
1244         *restrict q;
1245
1246       /*
1247         Colormap entry is defined by the mean color in this cube.
1248       */
1249       q=image->colormap+image->colors;
1250       alpha=(MagickRealType) ((MagickOffsetType) node_info->number_unique);
1251       alpha=MagickEpsilonReciprocal(alpha);
1252       if (cube_info->associate_alpha == MagickFalse)
1253         {
1254           q->red=(double) ClampToQuantum((MagickRealType)
1255             (alpha*QuantumRange*node_info->total_color.red));
1256           q->green=(double) ClampToQuantum((MagickRealType)
1257             (alpha*QuantumRange*node_info->total_color.green));
1258           q->blue=(double) ClampToQuantum((MagickRealType)
1259             (alpha*(double) QuantumRange*node_info->total_color.blue));
1260           q->alpha=OpaqueAlpha;
1261         }
1262       else
1263         {
1264           MagickRealType
1265             opacity;
1266
1267           opacity=(MagickRealType) (alpha*QuantumRange*
1268             node_info->total_color.alpha);
1269           q->alpha=(double) ClampToQuantum(opacity);
1270           if (q->alpha == OpaqueAlpha)
1271             {
1272               q->red=(double) ClampToQuantum((MagickRealType)
1273                 (alpha*QuantumRange*node_info->total_color.red));
1274               q->green=(double) ClampToQuantum((MagickRealType)
1275                 (alpha*QuantumRange*node_info->total_color.green));
1276               q->blue=(double) ClampToQuantum((MagickRealType)
1277                 (alpha*QuantumRange*node_info->total_color.blue));
1278             }
1279           else
1280             {
1281               MagickRealType
1282                 gamma;
1283
1284               gamma=(MagickRealType) (QuantumScale*q->alpha);
1285               gamma=MagickEpsilonReciprocal(gamma);
1286               q->red=(double) ClampToQuantum((MagickRealType)
1287                 (alpha*gamma*QuantumRange*node_info->total_color.red));
1288               q->green=(double) ClampToQuantum((MagickRealType)
1289                 (alpha*gamma*QuantumRange*node_info->total_color.green));
1290               q->blue=(double) ClampToQuantum((MagickRealType)
1291                 (alpha*gamma*QuantumRange*node_info->total_color.blue));
1292               if (node_info->number_unique > cube_info->transparent_pixels)
1293                 {
1294                   cube_info->transparent_pixels=node_info->number_unique;
1295                   cube_info->transparent_index=(ssize_t) image->colors;
1296                 }
1297             }
1298         }
1299       node_info->color_number=image->colors++;
1300     }
1301   return(image->colors);
1302 }
1303 \f
1304 /*
1305 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1306 %                                                                             %
1307 %                                                                             %
1308 %                                                                             %
1309 +   D e s t r o y C u b e I n f o                                             %
1310 %                                                                             %
1311 %                                                                             %
1312 %                                                                             %
1313 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1314 %
1315 %  DestroyCubeInfo() deallocates memory associated with an image.
1316 %
1317 %  The format of the DestroyCubeInfo method is:
1318 %
1319 %      DestroyCubeInfo(CubeInfo *cube_info)
1320 %
1321 %  A description of each parameter follows:
1322 %
1323 %    o cube_info: the address of a structure of type CubeInfo.
1324 %
1325 */
1326 static void DestroyCubeInfo(CubeInfo *cube_info)
1327 {
1328   register Nodes
1329     *nodes;
1330
1331   /*
1332     Release color cube tree storage.
1333   */
1334   do
1335   {
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);
1347 }
1348 \f
1349 /*
1350 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1351 %                                                                             %
1352 %                                                                             %
1353 %                                                                             %
1354 %   D e s t r o y Q u a n t i z e I n f o                                     %
1355 %                                                                             %
1356 %                                                                             %
1357 %                                                                             %
1358 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1359 %
1360 %  DestroyQuantizeInfo() deallocates memory associated with an QuantizeInfo
1361 %  structure.
1362 %
1363 %  The format of the DestroyQuantizeInfo method is:
1364 %
1365 %      QuantizeInfo *DestroyQuantizeInfo(QuantizeInfo *quantize_info)
1366 %
1367 %  A description of each parameter follows:
1368 %
1369 %    o quantize_info: Specifies a pointer to an QuantizeInfo structure.
1370 %
1371 */
1372 MagickExport QuantizeInfo *DestroyQuantizeInfo(QuantizeInfo *quantize_info)
1373 {
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);
1380 }
1381 \f
1382 /*
1383 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1384 %                                                                             %
1385 %                                                                             %
1386 %                                                                             %
1387 +   D i t h e r I m a g e                                                     %
1388 %                                                                             %
1389 %                                                                             %
1390 %                                                                             %
1391 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1392 %
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.
1397 %
1398 %  The format of the DitherImage method is:
1399 %
1400 %      MagickBooleanType DitherImage(Image *image,CubeInfo *cube_info,
1401 %        ExceptionInfo *exception)
1402 %
1403 %  A description of each parameter follows.
1404 %
1405 %    o image: the image.
1406 %
1407 %    o cube_info: A pointer to the Cube structure.
1408 %
1409 %    o exception: return any errors or warnings in this structure.
1410 %
1411 */
1412
1413 static RealPixelInfo **DestroyPixelThreadSet(RealPixelInfo **pixels)
1414 {
1415   register ssize_t
1416     i;
1417
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);
1423   return(pixels);
1424 }
1425
1426 static RealPixelInfo **AcquirePixelThreadSet(const size_t count)
1427 {
1428   RealPixelInfo
1429     **pixels;
1430
1431   register ssize_t
1432     i;
1433
1434   size_t
1435     number_threads;
1436
1437   number_threads=GetOpenMPMaximumThreads();
1438   pixels=(RealPixelInfo **) AcquireQuantumMemory(number_threads,
1439     sizeof(*pixels));
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++)
1444   {
1445     pixels[i]=(RealPixelInfo *) AcquireQuantumMemory(count,
1446       2*sizeof(**pixels));
1447     if (pixels[i] == (RealPixelInfo *) NULL)
1448       return(DestroyPixelThreadSet(pixels));
1449   }
1450   return(pixels);
1451 }
1452
1453 static inline ssize_t CacheOffset(CubeInfo *cube_info,
1454   const RealPixelInfo *pixel)
1455 {
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)))
1460
1461   ssize_t
1462     offset;
1463
1464   offset=(ssize_t)
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(
1470       pixel->alpha)));
1471   return(offset);
1472 }
1473
1474 static MagickBooleanType FloydSteinbergDither(Image *image,CubeInfo *cube_info,
1475   ExceptionInfo *exception)
1476 {
1477 #define DitherImageTag  "Dither/Image"
1478
1479   CacheView
1480     *image_view;
1481
1482   MagickBooleanType
1483     status;
1484
1485   RealPixelInfo
1486     **pixels;
1487
1488   ssize_t
1489     y;
1490
1491   /*
1492     Distribute quantization error using Floyd-Steinberg.
1493   */
1494   pixels=AcquirePixelThreadSet(image->columns);
1495   if (pixels == (RealPixelInfo **) NULL)
1496     return(MagickFalse);
1497   status=MagickTrue;
1498   image_view=AcquireAuthenticCacheView(image,exception);
1499   for (y=0; y < (ssize_t) image->rows; y++)
1500   {
1501     const int
1502       id = GetOpenMPThreadId();
1503
1504     CubeInfo
1505       cube;
1506
1507     RealPixelInfo
1508       *current,
1509       *previous;
1510
1511     register Quantum
1512       *restrict q;
1513
1514     register ssize_t
1515       x;
1516
1517     size_t
1518       index;
1519
1520     ssize_t
1521       v;
1522
1523     if (status == MagickFalse)
1524       continue;
1525     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
1526     if (q == (Quantum *) NULL)
1527       {
1528         status=MagickFalse;
1529         continue;
1530       }
1531     q+=(y & 0x01)*image->columns*GetPixelChannels(image);
1532     cube=(*cube_info);
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++)
1537     {
1538       RealPixelInfo
1539         color,
1540         pixel;
1541
1542       register ssize_t
1543         i;
1544
1545       ssize_t
1546         u;
1547
1548       q-=(y & 0x01)*GetPixelChannels(image);
1549       u=(y & 0x01) != 0 ? (ssize_t) image->columns-1-x : x;
1550       AssociateAlphaPixel(image,&cube,q,&pixel);
1551       if (x > 0)
1552         {
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;
1558         }
1559       if (y > 0)
1560         {
1561           if (x < (ssize_t) (image->columns-1))
1562             {
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;
1568             }
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;
1574           if (x > 0)
1575             {
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;
1581             }
1582         }
1583       pixel.red=(MagickRealType) ClampToUnsignedQuantum(pixel.red);
1584       pixel.green=(MagickRealType) ClampToUnsignedQuantum(pixel.green);
1585       pixel.blue=(MagickRealType) ClampToUnsignedQuantum(pixel.blue);
1586       if (cube.associate_alpha != MagickFalse)
1587         pixel.alpha=(MagickRealType) ClampToUnsignedQuantum(pixel.alpha);
1588       i=CacheOffset(&cube,&pixel);
1589       if (cube.cache[i] < 0)
1590         {
1591           register NodeInfo
1592             *node_info;
1593
1594           register size_t
1595             id;
1596
1597           /*
1598             Identify the deepest node containing the pixel's color.
1599           */
1600           node_info=cube.root;
1601           for (index=MaxTreeDepth-1; (ssize_t) index > 0; index--)
1602           {
1603             id=ColorToNodeId(&cube,&pixel,index);
1604             if (node_info->child[id] == (NodeInfo *) NULL)
1605               break;
1606             node_info=node_info->child[id];
1607           }
1608           /*
1609             Find closest color among siblings and their children.
1610           */
1611           cube.target=pixel;
1612           cube.distance=(MagickRealType) (4.0*(QuantumRange+1.0)*(QuantumRange+
1613             1.0)+1.0);
1614           ClosestColor(image,&cube,node_info->parent);
1615           cube.cache[i]=(ssize_t) cube.color_number;
1616         }
1617       /*
1618         Assign pixel to closest colormap entry.
1619       */
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)
1624         {
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);
1630         }
1631       if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1632         status=MagickFalse;
1633       /*
1634         Store the error.
1635       */
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)
1643         {
1644           MagickBooleanType
1645             proceed;
1646
1647 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1648           #pragma omp critical (MagickCore_FloydSteinbergDither)
1649 #endif
1650           proceed=SetImageProgress(image,DitherImageTag,(MagickOffsetType) y,
1651             image->rows);
1652           if (proceed == MagickFalse)
1653             status=MagickFalse;
1654         }
1655       q+=((y+1) & 0x01)*GetPixelChannels(image);
1656     }
1657   }
1658   image_view=DestroyCacheView(image_view);
1659   pixels=DestroyPixelThreadSet(pixels);
1660   return(MagickTrue);
1661 }
1662
1663 static MagickBooleanType
1664   RiemersmaDither(Image *,CacheView *,CubeInfo *,const unsigned int,
1665     ExceptionInfo *exception);
1666
1667 static void Riemersma(Image *image,CacheView *image_view,CubeInfo *cube_info,
1668   const size_t level,const unsigned int direction,ExceptionInfo *exception)
1669 {
1670   if (level == 1)
1671     switch (direction)
1672     {
1673       case WestGravity:
1674       {
1675         (void) RiemersmaDither(image,image_view,cube_info,EastGravity,
1676           exception);
1677         (void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
1678           exception);
1679         (void) RiemersmaDither(image,image_view,cube_info,WestGravity,
1680           exception);
1681         break;
1682       }
1683       case EastGravity:
1684       {
1685         (void) RiemersmaDither(image,image_view,cube_info,WestGravity,
1686           exception);
1687         (void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
1688           exception);
1689         (void) RiemersmaDither(image,image_view,cube_info,EastGravity,
1690           exception);
1691         break;
1692       }
1693       case NorthGravity:
1694       {
1695         (void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
1696           exception);
1697         (void) RiemersmaDither(image,image_view,cube_info,EastGravity,
1698           exception);
1699         (void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
1700           exception);
1701         break;
1702       }
1703       case SouthGravity:
1704       {
1705         (void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
1706           exception);
1707         (void) RiemersmaDither(image,image_view,cube_info,WestGravity,
1708           exception);
1709         (void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
1710           exception);
1711         break;
1712       }
1713       default:
1714         break;
1715     }
1716   else
1717     switch (direction)
1718     {
1719       case WestGravity:
1720       {
1721         Riemersma(image,image_view,cube_info,level-1,NorthGravity,
1722           exception);
1723         (void) RiemersmaDither(image,image_view,cube_info,EastGravity,
1724           exception);
1725         Riemersma(image,image_view,cube_info,level-1,WestGravity,
1726           exception);
1727         (void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
1728           exception);
1729         Riemersma(image,image_view,cube_info,level-1,WestGravity,
1730           exception);
1731         (void) RiemersmaDither(image,image_view,cube_info,WestGravity,
1732           exception);
1733         Riemersma(image,image_view,cube_info,level-1,SouthGravity,
1734           exception);
1735         break;
1736       }
1737       case EastGravity:
1738       {
1739         Riemersma(image,image_view,cube_info,level-1,SouthGravity,
1740           exception);
1741         (void) RiemersmaDither(image,image_view,cube_info,WestGravity,
1742           exception);
1743         Riemersma(image,image_view,cube_info,level-1,EastGravity,
1744           exception);
1745         (void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
1746           exception);
1747         Riemersma(image,image_view,cube_info,level-1,EastGravity,
1748           exception);
1749         (void) RiemersmaDither(image,image_view,cube_info,EastGravity,
1750           exception);
1751         Riemersma(image,image_view,cube_info,level-1,NorthGravity,
1752           exception);
1753         break;
1754       }
1755       case NorthGravity:
1756       {
1757         Riemersma(image,image_view,cube_info,level-1,WestGravity,
1758           exception);
1759         (void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
1760           exception);
1761         Riemersma(image,image_view,cube_info,level-1,NorthGravity,
1762           exception);
1763         (void) RiemersmaDither(image,image_view,cube_info,EastGravity,
1764           exception);
1765         Riemersma(image,image_view,cube_info,level-1,NorthGravity,
1766           exception);
1767         (void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
1768           exception);
1769         Riemersma(image,image_view,cube_info,level-1,EastGravity,
1770           exception);
1771         break;
1772       }
1773       case SouthGravity:
1774       {
1775         Riemersma(image,image_view,cube_info,level-1,EastGravity,
1776           exception);
1777         (void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
1778           exception);
1779         Riemersma(image,image_view,cube_info,level-1,SouthGravity,
1780           exception);
1781         (void) RiemersmaDither(image,image_view,cube_info,WestGravity,
1782           exception);
1783         Riemersma(image,image_view,cube_info,level-1,SouthGravity,
1784           exception);
1785         (void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
1786           exception);
1787         Riemersma(image,image_view,cube_info,level-1,WestGravity,
1788           exception);
1789         break;
1790       }
1791       default:
1792         break;
1793     }
1794 }
1795
1796 static MagickBooleanType RiemersmaDither(Image *image,CacheView *image_view,
1797   CubeInfo *cube_info,const unsigned int direction,ExceptionInfo *exception)
1798 {
1799 #define DitherImageTag  "Dither/Image"
1800
1801   MagickBooleanType
1802     proceed;
1803
1804   RealPixelInfo
1805     color,
1806     pixel;
1807
1808   register CubeInfo
1809     *p;
1810
1811   size_t
1812     index;
1813
1814   p=cube_info;
1815   if ((p->x >= 0) && (p->x < (ssize_t) image->columns) &&
1816       (p->y >= 0) && (p->y < (ssize_t) image->rows))
1817     {
1818       register Quantum
1819         *restrict q;
1820
1821       register ssize_t
1822         i;
1823
1824       /*
1825         Distribute error.
1826       */
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++)
1832       {
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;
1838       }
1839       pixel.red=(MagickRealType) ClampToUnsignedQuantum(pixel.red);
1840       pixel.green=(MagickRealType) ClampToUnsignedQuantum(pixel.green);
1841       pixel.blue=(MagickRealType) ClampToUnsignedQuantum(pixel.blue);
1842       if (cube_info->associate_alpha != MagickFalse)
1843         pixel.alpha=(MagickRealType) ClampToUnsignedQuantum(pixel.alpha);
1844       i=CacheOffset(cube_info,&pixel);
1845       if (p->cache[i] < 0)
1846         {
1847           register NodeInfo
1848             *node_info;
1849
1850           register size_t
1851             id;
1852
1853           /*
1854             Identify the deepest node containing the pixel's color.
1855           */
1856           node_info=p->root;
1857           for (index=MaxTreeDepth-1; (ssize_t) index > 0; index--)
1858           {
1859             id=ColorToNodeId(cube_info,&pixel,index);
1860             if (node_info->child[id] == (NodeInfo *) NULL)
1861               break;
1862             node_info=node_info->child[id];
1863           }
1864           node_info=node_info->parent;
1865           /*
1866             Find closest color among siblings and their children.
1867           */
1868           p->target=pixel;
1869           p->distance=(MagickRealType) (4.0*(QuantumRange+1.0)*((MagickRealType)
1870             QuantumRange+1.0)+1.0);
1871           ClosestColor(image,p,node_info->parent);
1872           p->cache[i]=(ssize_t) p->color_number;
1873         }
1874       /*
1875         Assign pixel to closest colormap entry.
1876       */
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)
1881         {
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);
1887         }
1888       if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1889         return(MagickFalse);
1890       /*
1891         Propagate the error as the last entry of the error queue.
1892       */
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);
1904       p->offset++;
1905     }
1906   switch (direction)
1907   {
1908     case WestGravity: p->x--; break;
1909     case EastGravity: p->x++; break;
1910     case NorthGravity: p->y--; break;
1911     case SouthGravity: p->y++; break;
1912   }
1913   return(MagickTrue);
1914 }
1915
1916 static inline ssize_t MagickMax(const ssize_t x,const ssize_t y)
1917 {
1918   if (x > y)
1919     return(x);
1920   return(y);
1921 }
1922
1923 static inline ssize_t MagickMin(const ssize_t x,const ssize_t y)
1924 {
1925   if (x < y)
1926     return(x);
1927   return(y);
1928 }
1929
1930 static MagickBooleanType DitherImage(Image *image,CubeInfo *cube_info,
1931   ExceptionInfo *exception)
1932 {
1933   CacheView
1934     *image_view;
1935
1936   MagickBooleanType
1937     status;
1938
1939   register ssize_t
1940     i;
1941
1942   size_t
1943     depth;
1944
1945   if (cube_info->quantize_info->dither_method != RiemersmaDitherMethod)
1946     return(FloydSteinbergDither(image,cube_info,exception));
1947   /*
1948     Distribute quantization error along a Hilbert curve.
1949   */
1950   (void) ResetMagickMemory(cube_info->error,0,ErrorQueueLength*
1951     sizeof(*cube_info->error));
1952   cube_info->x=0;
1953   cube_info->y=0;
1954   i=MagickMax((ssize_t) image->columns,(ssize_t) image->rows);
1955   for (depth=1; i != 0; depth++)
1956     i>>=1;
1957   if ((ssize_t) (1L << depth) < MagickMax((ssize_t) image->columns,(ssize_t) image->rows))
1958     depth++;
1959   cube_info->offset=0;
1960   cube_info->span=(MagickSizeType) image->columns*image->rows;
1961   image_view=AcquireAuthenticCacheView(image,exception);
1962   if (depth > 1)
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);
1966   return(status);
1967 }
1968 \f
1969 /*
1970 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1971 %                                                                             %
1972 %                                                                             %
1973 %                                                                             %
1974 +   G e t C u b e I n f o                                                     %
1975 %                                                                             %
1976 %                                                                             %
1977 %                                                                             %
1978 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1979 %
1980 %  GetCubeInfo() initialize the Cube data structure.
1981 %
1982 %  The format of the GetCubeInfo method is:
1983 %
1984 %      CubeInfo GetCubeInfo(const QuantizeInfo *quantize_info,
1985 %        const size_t depth,const size_t maximum_colors)
1986 %
1987 %  A description of each parameter follows.
1988 %
1989 %    o quantize_info: Specifies a pointer to an QuantizeInfo structure.
1990 %
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,
1998 %      use a value of 8.
1999 %
2000 %    o maximum_colors: maximum colors.
2001 %
2002 */
2003 static CubeInfo *GetCubeInfo(const QuantizeInfo *quantize_info,
2004   const size_t depth,const size_t maximum_colors)
2005 {
2006   CubeInfo
2007     *cube_info;
2008
2009   MagickRealType
2010     sum,
2011     weight;
2012
2013   register ssize_t
2014     i;
2015
2016   size_t
2017     length;
2018
2019   /*
2020     Initialize tree to describe color cube_info.
2021   */
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)
2030     cube_info->depth=2;
2031   cube_info->maximum_colors=maximum_colors;
2032   /*
2033     Initialize root node.
2034   */
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)
2041     return(cube_info);
2042   /*
2043     Initialize dither resources.
2044   */
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);
2050   /*
2051     Initialize color cache.
2052   */
2053   for (i=0; i < (ssize_t) length; i++)
2054     cube_info->cache[i]=(-1);
2055   /*
2056     Distribute weights along a curve of exponential decay.
2057   */
2058   weight=1.0;
2059   for (i=0; i < ErrorQueueLength; i++)
2060   {
2061     cube_info->weights[ErrorQueueLength-i-1]=MagickEpsilonReciprocal(weight);
2062     weight*=exp(log(((double) QuantumRange+1.0))/(ErrorQueueLength-1.0));
2063   }
2064   /*
2065     Normalize the weighting factors.
2066   */
2067   weight=0.0;
2068   for (i=0; i < ErrorQueueLength; i++)
2069     weight+=cube_info->weights[i];
2070   sum=0.0;
2071   for (i=0; i < ErrorQueueLength; i++)
2072   {
2073     cube_info->weights[i]/=weight;
2074     sum+=cube_info->weights[i];
2075   }
2076   cube_info->weights[0]+=1.0-sum;
2077   return(cube_info);
2078 }
2079 \f
2080 /*
2081 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2082 %                                                                             %
2083 %                                                                             %
2084 %                                                                             %
2085 +   G e t N o d e I n f o                                                     %
2086 %                                                                             %
2087 %                                                                             %
2088 %                                                                             %
2089 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2090 %
2091 %  GetNodeInfo() allocates memory for a new node in the color cube tree and
2092 %  presets all fields to zero.
2093 %
2094 %  The format of the GetNodeInfo method is:
2095 %
2096 %      NodeInfo *GetNodeInfo(CubeInfo *cube_info,const size_t id,
2097 %        const size_t level,NodeInfo *parent)
2098 %
2099 %  A description of each parameter follows.
2100 %
2101 %    o node: The GetNodeInfo method returns a pointer to a queue of nodes.
2102 %
2103 %    o id: Specifies the child number of the node.
2104 %
2105 %    o level: Specifies the level in the storage_class the node resides.
2106 %
2107 */
2108 static NodeInfo *GetNodeInfo(CubeInfo *cube_info,const size_t id,
2109   const size_t level,NodeInfo *parent)
2110 {
2111   NodeInfo
2112     *node_info;
2113
2114   if (cube_info->free_nodes == 0)
2115     {
2116       Nodes
2117         *nodes;
2118
2119       /*
2120         Allocate a new queue of nodes.
2121       */
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;
2133     }
2134   cube_info->nodes++;
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;
2139   node_info->id=id;
2140   node_info->level=level;
2141   return(node_info);
2142 }
2143 \f
2144 /*
2145 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2146 %                                                                             %
2147 %                                                                             %
2148 %                                                                             %
2149 %  G e t I m a g e Q u a n t i z e E r r o r                                  %
2150 %                                                                             %
2151 %                                                                             %
2152 %                                                                             %
2153 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2154 %
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:
2160 %
2161 %    o mean_error_per_pixel:  This value is the mean error for any single
2162 %      pixel in the image.
2163 %
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.
2168 %
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.
2173 %
2174 %  The format of the GetImageQuantizeError method is:
2175 %
2176 %      MagickBooleanType GetImageQuantizeError(Image *image,
2177 %        ExceptionInfo *exception)
2178 %
2179 %  A description of each parameter follows.
2180 %
2181 %    o image: the image.
2182 %
2183 %    o exception: return any errors or warnings in this structure.
2184 %
2185 */
2186 MagickExport MagickBooleanType GetImageQuantizeError(Image *image,
2187   ExceptionInfo *exception)
2188 {
2189   CacheView
2190     *image_view;
2191
2192   MagickRealType
2193     alpha,
2194     area,
2195     beta,
2196     distance,
2197     maximum_error,
2198     mean_error,
2199     mean_error_per_pixel;
2200
2201   size_t
2202     index;
2203
2204   ssize_t
2205     y;
2206
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)
2214     return(MagickTrue);
2215   alpha=1.0;
2216   beta=1.0;
2217   area=3.0*image->columns*image->rows;
2218   maximum_error=0.0;
2219   mean_error_per_pixel=0.0;
2220   mean_error=0.0;
2221   image_view=AcquireVirtualCacheView(image,exception);
2222   for (y=0; y < (ssize_t) image->rows; y++)
2223   {
2224     register const Quantum
2225       *restrict p;
2226
2227     register ssize_t
2228       x;
2229
2230     p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
2231     if (p == (const Quantum *) NULL)
2232       break;
2233     for (x=0; x < (ssize_t) image->columns; x++)
2234     {
2235       index=1UL*GetPixelIndex(image,p);
2236       if (image->matte != MagickFalse)
2237         {
2238           alpha=(MagickRealType) (QuantumScale*GetPixelAlpha(image,p));
2239           beta=(MagickRealType) (QuantumScale*image->colormap[index].alpha);
2240         }
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);
2260     }
2261   }
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*
2265     mean_error/area;
2266   image->error.normalized_maximum_error=(double) QuantumScale*maximum_error;
2267   return(MagickTrue);
2268 }
2269 \f
2270 /*
2271 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2272 %                                                                             %
2273 %                                                                             %
2274 %                                                                             %
2275 %   G e t Q u a n t i z e I n f o                                             %
2276 %                                                                             %
2277 %                                                                             %
2278 %                                                                             %
2279 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2280 %
2281 %  GetQuantizeInfo() initializes the QuantizeInfo structure.
2282 %
2283 %  The format of the GetQuantizeInfo method is:
2284 %
2285 %      GetQuantizeInfo(QuantizeInfo *quantize_info)
2286 %
2287 %  A description of each parameter follows:
2288 %
2289 %    o quantize_info: Specifies a pointer to a QuantizeInfo structure.
2290 %
2291 */
2292 MagickExport void GetQuantizeInfo(QuantizeInfo *quantize_info)
2293 {
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;
2302 }
2303 \f
2304 /*
2305 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2306 %                                                                             %
2307 %                                                                             %
2308 %                                                                             %
2309 %     P o s t e r i z e I m a g e                                             %
2310 %                                                                             %
2311 %                                                                             %
2312 %                                                                             %
2313 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2314 %
2315 %  PosterizeImage() reduces the image to a limited number of colors for a
2316 %  "poster" effect.
2317 %
2318 %  The format of the PosterizeImage method is:
2319 %
2320 %      MagickBooleanType PosterizeImage(Image *image,const size_t levels,
2321 %        const DitherMethod dither_method,ExceptionInfo *exception)
2322 %
2323 %  A description of each parameter follows:
2324 %
2325 %    o image: Specifies a pointer to an Image structure.
2326 %
2327 %    o levels: Number of color levels allowed in each channel.  Very low values
2328 %      (2, 3, or 4) have the most visible effect.
2329 %
2330 %    o dither_method: choose from UndefinedDitherMethod, NoDitherMethod,
2331 %      RiemersmaDitherMethod, FloydSteinbergDitherMethod.
2332 %
2333 %    o exception: return any errors or warnings in this structure.
2334 %
2335 */
2336
2337 static inline ssize_t MagickRound(MagickRealType x)
2338 {
2339   /*
2340     Round the fraction to nearest integer.
2341   */
2342   if (x >= 0.0)
2343     return((ssize_t) (x+0.5));
2344   return((ssize_t) (x-0.5));
2345 }
2346
2347 MagickExport MagickBooleanType PosterizeImage(Image *image,const size_t levels,
2348   const DitherMethod dither_method,ExceptionInfo *exception)
2349 {
2350 #define PosterizeImageTag  "Posterize/Image"
2351 #define PosterizePixel(pixel) (Quantum) (QuantumRange*(MagickRound( \
2352   QuantumScale*pixel*(levels-1)))/MagickMax((ssize_t) levels-1,1))
2353
2354   CacheView
2355     *image_view;
2356
2357   MagickBooleanType
2358     status;
2359
2360   MagickOffsetType
2361     progress;
2362
2363   QuantizeInfo
2364     *quantize_info;
2365
2366   register ssize_t
2367     i;
2368
2369   ssize_t
2370     y;
2371
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)
2380 #endif
2381     for (i=0; i < (ssize_t) image->colors; i++)
2382     {
2383       /*
2384         Posterize colormap.
2385       */
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);
2398     }
2399   /*
2400     Posterize image.
2401   */
2402   status=MagickTrue;
2403   progress=0;
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)
2408 #endif
2409   for (y=0; y < (ssize_t) image->rows; y++)
2410   {
2411     register Quantum
2412       *restrict q;
2413
2414     register ssize_t
2415       x;
2416
2417     if (status == MagickFalse)
2418       continue;
2419     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
2420     if (q == (Quantum *) NULL)
2421       {
2422         status=MagickFalse;
2423         continue;
2424       }
2425     for (x=0; x < (ssize_t) image->columns; x++)
2426     {
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);
2440     }
2441     if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
2442       status=MagickFalse;
2443     if (image->progress_monitor != (MagickProgressMonitor) NULL)
2444       {
2445         MagickBooleanType
2446           proceed;
2447
2448 #if defined(MAGICKCORE_OPENMP_SUPPORT)
2449         #pragma omp critical (MagickCore_PosterizeImage)
2450 #endif
2451         proceed=SetImageProgress(image,PosterizeImageTag,progress++,
2452           image->rows);
2453         if (proceed == MagickFalse)
2454           status=MagickFalse;
2455       }
2456   }
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);
2465   return(status);
2466 }
2467 \f
2468 /*
2469 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2470 %                                                                             %
2471 %                                                                             %
2472 %                                                                             %
2473 +   P r u n e C h i l d                                                       %
2474 %                                                                             %
2475 %                                                                             %
2476 %                                                                             %
2477 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2478 %
2479 %  PruneChild() deletes the given node and merges its statistics into its
2480 %  parent.
2481 %
2482 %  The format of the PruneSubtree method is:
2483 %
2484 %      PruneChild(const Image *image,CubeInfo *cube_info,
2485 %        const NodeInfo *node_info)
2486 %
2487 %  A description of each parameter follows.
2488 %
2489 %    o image: the image.
2490 %
2491 %    o cube_info: A pointer to the Cube structure.
2492 %
2493 %    o node_info: pointer to node in color cube tree that is to be pruned.
2494 %
2495 */
2496 static void PruneChild(const Image *image,CubeInfo *cube_info,
2497   const NodeInfo *node_info)
2498 {
2499   NodeInfo
2500     *parent;
2501
2502   register ssize_t
2503     i;
2504
2505   size_t
2506     number_children;
2507
2508   /*
2509     Traverse any children.
2510   */
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]);
2515   /*
2516     Merge color statistics into parent.
2517   */
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;
2525   cube_info->nodes--;
2526 }
2527 \f
2528 /*
2529 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2530 %                                                                             %
2531 %                                                                             %
2532 %                                                                             %
2533 +  P r u n e L e v e l                                                        %
2534 %                                                                             %
2535 %                                                                             %
2536 %                                                                             %
2537 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2538 %
2539 %  PruneLevel() deletes all nodes at the bottom level of the color tree merging
2540 %  their color statistics into their parent node.
2541 %
2542 %  The format of the PruneLevel method is:
2543 %
2544 %      PruneLevel(const Image *image,CubeInfo *cube_info,
2545 %        const NodeInfo *node_info)
2546 %
2547 %  A description of each parameter follows.
2548 %
2549 %    o image: the image.
2550 %
2551 %    o cube_info: A pointer to the Cube structure.
2552 %
2553 %    o node_info: pointer to node in color cube tree that is to be pruned.
2554 %
2555 */
2556 static void PruneLevel(const Image *image,CubeInfo *cube_info,
2557   const NodeInfo *node_info)
2558 {
2559   register ssize_t
2560     i;
2561
2562   size_t
2563     number_children;
2564
2565   /*
2566     Traverse any children.
2567   */
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);
2574 }
2575 \f
2576 /*
2577 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2578 %                                                                             %
2579 %                                                                             %
2580 %                                                                             %
2581 +  P r u n e T o C u b e D e p t h                                            %
2582 %                                                                             %
2583 %                                                                             %
2584 %                                                                             %
2585 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2586 %
2587 %  PruneToCubeDepth() deletes any nodes at a depth greater than
2588 %  cube_info->depth while merging their color statistics into their parent
2589 %  node.
2590 %
2591 %  The format of the PruneToCubeDepth method is:
2592 %
2593 %      PruneToCubeDepth(const Image *image,CubeInfo *cube_info,
2594 %        const NodeInfo *node_info)
2595 %
2596 %  A description of each parameter follows.
2597 %
2598 %    o cube_info: A pointer to the Cube structure.
2599 %
2600 %    o node_info: pointer to node in color cube tree that is to be pruned.
2601 %
2602 */
2603 static void PruneToCubeDepth(const Image *image,CubeInfo *cube_info,
2604   const NodeInfo *node_info)
2605 {
2606   register ssize_t
2607     i;
2608
2609   size_t
2610     number_children;
2611
2612   /*
2613     Traverse any children.
2614   */
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);
2621 }
2622 \f
2623 /*
2624 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2625 %                                                                             %
2626 %                                                                             %
2627 %                                                                             %
2628 %  Q u a n t i z e I m a g e                                                  %
2629 %                                                                             %
2630 %                                                                             %
2631 %                                                                             %
2632 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2633 %
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.
2638 %
2639 %  The format of the QuantizeImage method is:
2640 %
2641 %      MagickBooleanType QuantizeImage(const QuantizeInfo *quantize_info,
2642 %        Image *image,ExceptionInfo *exception)
2643 %
2644 %  A description of each parameter follows:
2645 %
2646 %    o quantize_info: Specifies a pointer to an QuantizeInfo structure.
2647 %
2648 %    o image: the image.
2649 %
2650 %    o exception: return any errors or warnings in this structure.
2651 %
2652 */
2653
2654 static MagickBooleanType DirectToColormapImage(Image *image,
2655   ExceptionInfo *exception)
2656 {
2657   CacheView
2658     *image_view;
2659
2660   MagickBooleanType
2661     status;
2662
2663   register ssize_t
2664     i;
2665
2666   size_t
2667     number_colors;
2668
2669   ssize_t
2670     y;
2671
2672   status=MagickTrue;
2673   number_colors=(size_t) (image->columns*image->rows);
2674   if (AcquireImageColormap(image,number_colors,exception) == MagickFalse)
2675     ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
2676       image->filename);
2677   if (image->colors != number_colors)
2678     return(MagickFalse);
2679   i=0;
2680   image_view=AcquireAuthenticCacheView(image,exception);
2681   for (y=0; y < (ssize_t) image->rows; y++)
2682   {
2683     MagickBooleanType
2684       proceed;
2685
2686     register Quantum
2687       *restrict q;
2688
2689     register ssize_t
2690       x;
2691
2692     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
2693     if (q == (Quantum *) NULL)
2694       break;
2695     for (x=0; x < (ssize_t) image->columns; x++)
2696     {
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);
2702       i++;
2703       q+=GetPixelChannels(image);
2704     }
2705     if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
2706       break;
2707     proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) y,
2708       image->rows);
2709     if (proceed == MagickFalse)
2710       status=MagickFalse;
2711   }
2712   image_view=DestroyCacheView(image_view);
2713   return(status);
2714 }
2715
2716 MagickExport MagickBooleanType QuantizeImage(const QuantizeInfo *quantize_info,
2717   Image *image,ExceptionInfo *exception)
2718 {
2719   CubeInfo
2720     *cube_info;
2721
2722   MagickBooleanType
2723     status;
2724
2725   size_t
2726     depth,
2727     maximum_colors;
2728
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->columns*image->rows) <= maximum_colors)
2741     (void) DirectToColormapImage(image,exception);
2742   if ((IsImageGray(image,exception) != MagickFalse) &&
2743       (image->matte == MagickFalse))
2744     (void) SetGrayscaleImage(image,exception);
2745   if ((image->storage_class == PseudoClass) &&
2746       (image->colors <= maximum_colors))
2747     return(MagickTrue);
2748   depth=quantize_info->tree_depth;
2749   if (depth == 0)
2750     {
2751       size_t
2752         colors;
2753
2754       /*
2755         Depth of color tree is: Log4(colormap size)+2.
2756       */
2757       colors=maximum_colors;
2758       for (depth=1; colors != 0; depth++)
2759         colors>>=2;
2760       if ((quantize_info->dither_method != NoDitherMethod) && (depth > 2))
2761         depth--;
2762       if ((image->matte != MagickFalse) && (depth > 5))
2763         depth--;
2764     }
2765   /*
2766     Initialize color cube.
2767   */
2768   cube_info=GetCubeInfo(quantize_info,depth,maximum_colors);
2769   if (cube_info == (CubeInfo *) NULL)
2770     ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
2771       image->filename);
2772   status=ClassifyImageColors(cube_info,image,exception);
2773   if (status != MagickFalse)
2774     {
2775       /*
2776         Reduce the number of colors in the image.
2777       */
2778       ReduceImageColors(image,cube_info);
2779       status=AssignImageColors(image,cube_info,exception);
2780     }
2781   DestroyCubeInfo(cube_info);
2782   return(status);
2783 }
2784 \f
2785 /*
2786 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2787 %                                                                             %
2788 %                                                                             %
2789 %                                                                             %
2790 %   Q u a n t i z e I m a g e s                                               %
2791 %                                                                             %
2792 %                                                                             %
2793 %                                                                             %
2794 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2795 %
2796 %  QuantizeImages() analyzes the colors within a set of reference images and
2797 %  chooses a fixed number of colors to represent the set.  The goal of the
2798 %  algorithm is to minimize the color difference between the input and output
2799 %  images while minimizing the processing time.
2800 %
2801 %  The format of the QuantizeImages method is:
2802 %
2803 %      MagickBooleanType QuantizeImages(const QuantizeInfo *quantize_info,
2804 %        Image *images,ExceptionInfo *exception)
2805 %
2806 %  A description of each parameter follows:
2807 %
2808 %    o quantize_info: Specifies a pointer to an QuantizeInfo structure.
2809 %
2810 %    o images: Specifies a pointer to a list of Image structures.
2811 %
2812 %    o exception: return any errors or warnings in this structure.
2813 %
2814 */
2815 MagickExport MagickBooleanType QuantizeImages(const QuantizeInfo *quantize_info,
2816   Image *images,ExceptionInfo *exception)
2817 {
2818   CubeInfo
2819     *cube_info;
2820
2821   Image
2822     *image;
2823
2824   MagickBooleanType
2825     proceed,
2826     status;
2827
2828   MagickProgressMonitor
2829     progress_monitor;
2830
2831   register ssize_t
2832     i;
2833
2834   size_t
2835     depth,
2836     maximum_colors,
2837     number_images;
2838
2839   assert(quantize_info != (const QuantizeInfo *) NULL);
2840   assert(quantize_info->signature == MagickSignature);
2841   assert(images != (Image *) NULL);
2842   assert(images->signature == MagickSignature);
2843   if (images->debug != MagickFalse)
2844     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",images->filename);
2845   if (GetNextImageInList(images) == (Image *) NULL)
2846     {
2847       /*
2848         Handle a single image with QuantizeImage.
2849       */
2850       status=QuantizeImage(quantize_info,images,exception);
2851       return(status);
2852     }
2853   status=MagickFalse;
2854   maximum_colors=quantize_info->number_colors;
2855   if (maximum_colors == 0)
2856     maximum_colors=MaxColormapSize;
2857   if (maximum_colors > MaxColormapSize)
2858     maximum_colors=MaxColormapSize;
2859   depth=quantize_info->tree_depth;
2860   if (depth == 0)
2861     {
2862       size_t
2863         colors;
2864
2865       /*
2866         Depth of color tree is: Log4(colormap size)+2.
2867       */
2868       colors=maximum_colors;
2869       for (depth=1; colors != 0; depth++)
2870         colors>>=2;
2871       if (quantize_info->dither_method != NoDitherMethod)
2872         depth--;
2873     }
2874   /*
2875     Initialize color cube.
2876   */
2877   cube_info=GetCubeInfo(quantize_info,depth,maximum_colors);
2878   if (cube_info == (CubeInfo *) NULL)
2879     {
2880       (void) ThrowMagickException(exception,GetMagickModule(),
2881         ResourceLimitError,"MemoryAllocationFailed","'%s'",images->filename);
2882       return(MagickFalse);
2883     }
2884   number_images=GetImageListLength(images);
2885   image=images;
2886   for (i=0; image != (Image *) NULL; i++)
2887   {
2888     progress_monitor=SetImageProgressMonitor(image,(MagickProgressMonitor) NULL,
2889       image->client_data);
2890     status=ClassifyImageColors(cube_info,image,exception);
2891     if (status == MagickFalse)
2892       break;
2893     (void) SetImageProgressMonitor(image,progress_monitor,image->client_data);
2894     proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) i,
2895       number_images);
2896     if (proceed == MagickFalse)
2897       break;
2898     image=GetNextImageInList(image);
2899   }
2900   if (status != MagickFalse)
2901     {
2902       /*
2903         Reduce the number of colors in an image sequence.
2904       */
2905       ReduceImageColors(images,cube_info);
2906       image=images;
2907       for (i=0; image != (Image *) NULL; i++)
2908       {
2909         progress_monitor=SetImageProgressMonitor(image,(MagickProgressMonitor)
2910           NULL,image->client_data);
2911         status=AssignImageColors(image,cube_info,exception);
2912         if (status == MagickFalse)
2913           break;
2914         (void) SetImageProgressMonitor(image,progress_monitor,
2915           image->client_data);
2916         proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) i,
2917           number_images);
2918         if (proceed == MagickFalse)
2919           break;
2920         image=GetNextImageInList(image);
2921       }
2922     }
2923   DestroyCubeInfo(cube_info);
2924   return(status);
2925 }
2926 \f
2927 /*
2928 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2929 %                                                                             %
2930 %                                                                             %
2931 %                                                                             %
2932 +   R e d u c e                                                               %
2933 %                                                                             %
2934 %                                                                             %
2935 %                                                                             %
2936 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2937 %
2938 %  Reduce() traverses the color cube tree and prunes any node whose
2939 %  quantization error falls below a particular threshold.
2940 %
2941 %  The format of the Reduce method is:
2942 %
2943 %      Reduce(const Image *image,CubeInfo *cube_info,const NodeInfo *node_info)
2944 %
2945 %  A description of each parameter follows.
2946 %
2947 %    o image: the image.
2948 %
2949 %    o cube_info: A pointer to the Cube structure.
2950 %
2951 %    o node_info: pointer to node in color cube tree that is to be pruned.
2952 %
2953 */
2954 static void Reduce(const Image *image,CubeInfo *cube_info,
2955   const NodeInfo *node_info)
2956 {
2957   register ssize_t
2958     i;
2959
2960   size_t
2961     number_children;
2962
2963   /*
2964     Traverse any children.
2965   */
2966   number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2967   for (i=0; i < (ssize_t) number_children; i++)
2968     if (node_info->child[i] != (NodeInfo *) NULL)
2969       Reduce(image,cube_info,node_info->child[i]);
2970   if (node_info->quantize_error <= cube_info->pruning_threshold)
2971     PruneChild(image,cube_info,node_info);
2972   else
2973     {
2974       /*
2975         Find minimum pruning threshold.
2976       */
2977       if (node_info->number_unique > 0)
2978         cube_info->colors++;
2979       if (node_info->quantize_error < cube_info->next_threshold)
2980         cube_info->next_threshold=node_info->quantize_error;
2981     }
2982 }
2983 \f
2984 /*
2985 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2986 %                                                                             %
2987 %                                                                             %
2988 %                                                                             %
2989 +   R e d u c e I m a g e C o l o r s                                         %
2990 %                                                                             %
2991 %                                                                             %
2992 %                                                                             %
2993 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2994 %
2995 %  ReduceImageColors() repeatedly prunes the tree until the number of nodes
2996 %  with n2 > 0 is less than or equal to the maximum number of colors allowed
2997 %  in the output image.  On any given iteration over the tree, it selects
2998 %  those nodes whose E value is minimal for pruning and merges their
2999 %  color statistics upward. It uses a pruning threshold, Ep, to govern
3000 %  node selection as follows:
3001 %
3002 %    Ep = 0
3003 %    while number of nodes with (n2 > 0) > required maximum number of colors
3004 %      prune all nodes such that E <= Ep
3005 %      Set Ep to minimum E in remaining nodes
3006 %
3007 %  This has the effect of minimizing any quantization error when merging
3008 %  two nodes together.
3009 %
3010 %  When a node to be pruned has offspring, the pruning procedure invokes
3011 %  itself recursively in order to prune the tree from the leaves upward.
3012 %  n2,  Sr, Sg,  and  Sb in a node being pruned are always added to the
3013 %  corresponding data in that node's parent.  This retains the pruned
3014 %  node's color characteristics for later averaging.
3015 %
3016 %  For each node, n2 pixels exist for which that node represents the
3017 %  smallest volume in RGB space containing those pixel's colors.  When n2
3018 %  > 0 the node will uniquely define a color in the output image. At the
3019 %  beginning of reduction,  n2 = 0  for all nodes except a the leaves of
3020 %  the tree which represent colors present in the input image.
3021 %
3022 %  The other pixel count, n1, indicates the total number of colors
3023 %  within the cubic volume which the node represents.  This includes n1 -
3024 %  n2  pixels whose colors should be defined by nodes at a lower level in
3025 %  the tree.
3026 %
3027 %  The format of the ReduceImageColors method is:
3028 %
3029 %      ReduceImageColors(const Image *image,CubeInfo *cube_info)
3030 %
3031 %  A description of each parameter follows.
3032 %
3033 %    o image: the image.
3034 %
3035 %    o cube_info: A pointer to the Cube structure.
3036 %
3037 */
3038 static void ReduceImageColors(const Image *image,CubeInfo *cube_info)
3039 {
3040 #define ReduceImageTag  "Reduce/Image"
3041
3042   MagickBooleanType
3043     proceed;
3044
3045   MagickOffsetType
3046     offset;
3047
3048   size_t
3049     span;
3050
3051   cube_info->next_threshold=0.0;
3052   for (span=cube_info->colors; cube_info->colors > cube_info->maximum_colors; )
3053   {
3054     cube_info->pruning_threshold=cube_info->next_threshold;
3055     cube_info->next_threshold=cube_info->root->quantize_error-1;
3056     cube_info->colors=0;
3057     Reduce(image,cube_info,cube_info->root);
3058     offset=(MagickOffsetType) span-cube_info->colors;
3059     proceed=SetImageProgress(image,ReduceImageTag,offset,span-
3060       cube_info->maximum_colors+1);
3061     if (proceed == MagickFalse)
3062       break;
3063   }
3064 }
3065 \f
3066 /*
3067 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3068 %                                                                             %
3069 %                                                                             %
3070 %                                                                             %
3071 %   R e m a p I m a g e                                                       %
3072 %                                                                             %
3073 %                                                                             %
3074 %                                                                             %
3075 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3076 %
3077 %  RemapImage() replaces the colors of an image with a dither of the colors
3078 %  provided.
3079 %
3080 %  The format of the RemapImage method is:
3081 %
3082 %      MagickBooleanType RemapImage(const QuantizeInfo *quantize_info,
3083 %        Image *image,const Image *remap_image,ExceptionInfo *exception)
3084 %
3085 %  A description of each parameter follows:
3086 %
3087 %    o quantize_info: Specifies a pointer to an QuantizeInfo structure.
3088 %
3089 %    o image: the image.
3090 %
3091 %    o remap_image: the reference image.
3092 %
3093 %    o exception: return any errors or warnings in this structure.
3094 %
3095 */
3096 MagickExport MagickBooleanType RemapImage(const QuantizeInfo *quantize_info,
3097   Image *image,const Image *remap_image,ExceptionInfo *exception)
3098 {
3099   CubeInfo
3100     *cube_info;
3101
3102   MagickBooleanType
3103     status;
3104
3105   /*
3106     Initialize color cube.
3107   */
3108   assert(image != (Image *) NULL);
3109   assert(image->signature == MagickSignature);
3110   if (image->debug != MagickFalse)
3111     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
3112   assert(remap_image != (Image *) NULL);
3113   assert(remap_image->signature == MagickSignature);
3114   cube_info=GetCubeInfo(quantize_info,MaxTreeDepth,
3115     quantize_info->number_colors);
3116   if (cube_info == (CubeInfo *) NULL)
3117     ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3118       image->filename);
3119   status=ClassifyImageColors(cube_info,remap_image,exception);
3120   if (status != MagickFalse)
3121     {
3122       /*
3123         Classify image colors from the reference image.
3124       */
3125       cube_info->quantize_info->number_colors=cube_info->colors;
3126       status=AssignImageColors(image,cube_info,exception);
3127     }
3128   DestroyCubeInfo(cube_info);
3129   return(status);
3130 }
3131 \f
3132 /*
3133 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3134 %                                                                             %
3135 %                                                                             %
3136 %                                                                             %
3137 %   R e m a p I m a g e s                                                     %
3138 %                                                                             %
3139 %                                                                             %
3140 %                                                                             %
3141 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3142 %
3143 %  RemapImages() replaces the colors of a sequence of images with the
3144 %  closest color from a reference image.
3145 %
3146 %  The format of the RemapImage method is:
3147 %
3148 %      MagickBooleanType RemapImages(const QuantizeInfo *quantize_info,
3149 %        Image *images,Image *remap_image,ExceptionInfo *exception)
3150 %
3151 %  A description of each parameter follows:
3152 %
3153 %    o quantize_info: Specifies a pointer to an QuantizeInfo structure.
3154 %
3155 %    o images: the image sequence.
3156 %
3157 %    o remap_image: the reference image.
3158 %
3159 %    o exception: return any errors or warnings in this structure.
3160 %
3161 */
3162 MagickExport MagickBooleanType RemapImages(const QuantizeInfo *quantize_info,
3163   Image *images,const Image *remap_image,ExceptionInfo *exception)
3164 {
3165   CubeInfo
3166     *cube_info;
3167
3168   Image
3169     *image;
3170
3171   MagickBooleanType
3172     status;
3173
3174   assert(images != (Image *) NULL);
3175   assert(images->signature == MagickSignature);
3176   if (images->debug != MagickFalse)
3177     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",images->filename);
3178   image=images;
3179   if (remap_image == (Image *) NULL)
3180     {
3181       /*
3182         Create a global colormap for an image sequence.
3183       */
3184       status=QuantizeImages(quantize_info,images,exception);
3185       return(status);
3186     }
3187   /*
3188     Classify image colors from the reference image.
3189   */
3190   cube_info=GetCubeInfo(quantize_info,MaxTreeDepth,
3191     quantize_info->number_colors);
3192   if (cube_info == (CubeInfo *) NULL)
3193     ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3194       image->filename);
3195   status=ClassifyImageColors(cube_info,remap_image,exception);
3196   if (status != MagickFalse)
3197     {
3198       /*
3199         Classify image colors from the reference image.
3200       */
3201       cube_info->quantize_info->number_colors=cube_info->colors;
3202       image=images;
3203       for ( ; image != (Image *) NULL; image=GetNextImageInList(image))
3204       {
3205         status=AssignImageColors(image,cube_info,exception);
3206         if (status == MagickFalse)
3207           break;
3208       }
3209     }
3210   DestroyCubeInfo(cube_info);
3211   return(status);
3212 }
3213 \f
3214 /*
3215 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3216 %                                                                             %
3217 %                                                                             %
3218 %                                                                             %
3219 %   S e t G r a y s c a l e I m a g e                                         %
3220 %                                                                             %
3221 %                                                                             %
3222 %                                                                             %
3223 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3224 %
3225 %  SetGrayscaleImage() converts an image to a PseudoClass grayscale image.
3226 %
3227 %  The format of the SetGrayscaleImage method is:
3228 %
3229 %      MagickBooleanType SetGrayscaleImage(Image *image,ExceptionInfo *exeption)
3230 %
3231 %  A description of each parameter follows:
3232 %
3233 %    o image: The image.
3234 %
3235 %    o exception: return any errors or warnings in this structure.
3236 %
3237 */
3238
3239 #if defined(__cplusplus) || defined(c_plusplus)
3240 extern "C" {
3241 #endif
3242
3243 static int IntensityCompare(const void *x,const void *y)
3244 {
3245   PixelInfo
3246     *color_1,
3247     *color_2;
3248
3249   ssize_t
3250     intensity;
3251
3252   color_1=(PixelInfo *) x;
3253   color_2=(PixelInfo *) y;
3254   intensity=GetPixelInfoIntensity(color_1)-(ssize_t)
3255     GetPixelInfoIntensity(color_2);
3256   return((int) intensity);
3257 }
3258
3259 #if defined(__cplusplus) || defined(c_plusplus)
3260 }
3261 #endif
3262
3263 static MagickBooleanType SetGrayscaleImage(Image *image,
3264   ExceptionInfo *exception)
3265 {
3266   CacheView
3267     *image_view;
3268
3269   MagickBooleanType
3270     status;
3271
3272   PixelInfo
3273     *colormap;
3274
3275   register ssize_t
3276     i;
3277
3278   ssize_t
3279     *colormap_index,
3280     j,
3281     y;
3282
3283   assert(image != (Image *) NULL);
3284   assert(image->signature == MagickSignature);
3285   if (image->type != GrayscaleType)
3286     (void) TransformImageColorspace(image,GRAYColorspace,exception);
3287   colormap_index=(ssize_t *) AcquireQuantumMemory(MaxMap+1,
3288     sizeof(*colormap_index));
3289   if (colormap_index == (ssize_t *) NULL)
3290     ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3291       image->filename);
3292   if (image->storage_class != PseudoClass)
3293     {
3294       for (i=0; i <= (ssize_t) MaxMap; i++)
3295         colormap_index[i]=(-1);
3296       if (AcquireImageColormap(image,MaxMap+1,exception) == MagickFalse)
3297         ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3298           image->filename);
3299       image->colors=0;
3300       status=MagickTrue;
3301       image_view=AcquireAuthenticCacheView(image,exception);
3302 #if defined(MAGICKCORE_OPENMP_SUPPORT)
3303       #pragma omp parallel for schedule(static,4) shared(status) \
3304         dynamic_number_threads(image,image->columns,image->rows,1)
3305 #endif
3306       for (y=0; y < (ssize_t) image->rows; y++)
3307       {
3308         register Quantum
3309           *restrict q;
3310
3311         register ssize_t
3312           x;
3313
3314         if (status == MagickFalse)
3315           continue;
3316         q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,
3317           exception);
3318         if (q == (Quantum *) NULL)
3319           {
3320             status=MagickFalse;
3321             continue;
3322           }
3323         for (x=0; x < (ssize_t) image->columns; x++)
3324         {
3325           register size_t
3326             intensity;
3327
3328           intensity=ScaleQuantumToMap(GetPixelRed(image,q));
3329           if (colormap_index[intensity] < 0)
3330             {
3331 #if defined(MAGICKCORE_OPENMP_SUPPORT)
3332               #pragma omp critical (MagickCore_SetGrayscaleImage)
3333 #endif
3334               if (colormap_index[intensity] < 0)
3335                 {
3336                   colormap_index[intensity]=(ssize_t) image->colors;
3337                   image->colormap[image->colors].red=(double)
3338                     GetPixelRed(image,q);
3339                   image->colormap[image->colors].green=(double)
3340                     GetPixelGreen(image,q);
3341                   image->colormap[image->colors].blue=(double)
3342                     GetPixelBlue(image,q);
3343                   image->colors++;
3344                }
3345             }
3346           SetPixelIndex(image,(Quantum)
3347             colormap_index[intensity],q);
3348           q+=GetPixelChannels(image);
3349         }
3350         if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
3351           status=MagickFalse;
3352       }
3353       image_view=DestroyCacheView(image_view);
3354     }
3355   for (i=0; i < (ssize_t) image->colors; i++)
3356     image->colormap[i].alpha=(double) i;
3357   qsort((void *) image->colormap,image->colors,sizeof(PixelInfo),
3358     IntensityCompare);
3359   colormap=(PixelInfo *) AcquireQuantumMemory(image->colors,
3360     sizeof(*colormap));
3361   if (colormap == (PixelInfo *) NULL)
3362     ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3363       image->filename);
3364   j=0;
3365   colormap[j]=image->colormap[0];
3366   for (i=0; i < (ssize_t) image->colors; i++)
3367   {
3368     if (IsPixelInfoEquivalent(&colormap[j],&image->colormap[i]) == MagickFalse)
3369       {
3370         j++;
3371         colormap[j]=image->colormap[i];
3372       }
3373     colormap_index[(ssize_t) image->colormap[i].alpha]=j;
3374   }
3375   image->colors=(size_t) (j+1);
3376   image->colormap=(PixelInfo *) RelinquishMagickMemory(image->colormap);
3377   image->colormap=colormap;
3378   status=MagickTrue;
3379   image_view=AcquireAuthenticCacheView(image,exception);
3380 #if defined(MAGICKCORE_OPENMP_SUPPORT)
3381   #pragma omp parallel for schedule(static,4) shared(status) \
3382     dynamic_number_threads(image,image->columns,image->rows,1)
3383 #endif
3384   for (y=0; y < (ssize_t) image->rows; y++)
3385   {
3386     register Quantum
3387       *restrict q;
3388
3389     register ssize_t
3390       x;
3391
3392     if (status == MagickFalse)
3393       continue;
3394     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
3395     if (q == (Quantum *) NULL)
3396       {
3397         status=MagickFalse;
3398         continue;
3399       }
3400     for (x=0; x < (ssize_t) image->columns; x++)
3401     {
3402       SetPixelIndex(image,(Quantum) colormap_index[ScaleQuantumToMap(
3403         GetPixelIndex(image,q))],q);
3404       q+=GetPixelChannels(image);
3405     }
3406     if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
3407       status=MagickFalse;
3408   }
3409   image_view=DestroyCacheView(image_view);
3410   colormap_index=(ssize_t *) RelinquishMagickMemory(colormap_index);
3411   image->type=GrayscaleType;
3412   if (IsImageMonochrome(image,exception) != MagickFalse)
3413     image->type=BilevelType;
3414   return(status);
3415 }