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                %
  10 %           QQQQ   UUU   A   A  N   N    T    IIIII   ZZZZZ  EEEEE            %
  11 %                                                                             %
  12 %                                                                             %
  13 %    MagickCore Methods to Reduce the Number of Unique Colors in an Image     %
  14 %                                                                             %
  15 %                           Software Design                                   %
  16 %                                Cristy                                       %
  17 %                              July 1992                                      %
  18 %                                                                             %
  19 %                                                                             %
  20 %  Copyright 1999-2018 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 %    https://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 (vertex
  65 %  nearest the origin in RGB space and the vertex farthest from the origin).
  66 %
  67 %  The tree's root node represents the entire domain, (0,0,0) through
  68 %  (Cmax,Cmax,Cmax).  Each lower level in the tree is generated by
  69 %  subdividing one node's cube into eight smaller cubes of equal size.
  70 %  This corresponds to bisecting the parent cube with planes passing
  71 %  through the midpoints of each edge.
  72 %
  73 %  The basic algorithm operates in three phases: Classification,
  74 %  Reduction, and Assignment.  Classification builds a color description
  75 %  tree for the image.  Reduction collapses the tree until the number it
  76 %  represents, at most, the number of colors desired in the output image.
  77 %  Assignment defines the output image's color map and sets each pixel's
  78 %  color by restorage_class in the reduced tree.  Our goal is to minimize
  79 %  the numerical discrepancies between the original colors and quantized
  80 %  colors (quantization error).
  81 %
  82 %  Classification begins by initializing a color description tree of
  83 %  sufficient depth to represent each possible input color in a leaf.
  84 %  However, it is impractical to generate a fully-formed color description
  85 %  tree in the storage_class phase for realistic values of Cmax.  If
  86 %  colors components in the input image are quantized to k-bit precision,
  87 %  so that Cmax= 2k-1, the tree would need k levels below the root node to
  88 %  allow representing each possible input color in a leaf.  This becomes
  89 %  prohibitive because the tree's total number of nodes is 1 +
  90 %  sum(i=1, k, 8k).
  91 %
  92 %  A complete tree would require 19,173,961 nodes for k = 8, Cmax = 255.
  93 %  Therefore, to avoid building a fully populated tree, QUANTIZE: (1)
  94 %  Initializes data structures for nodes only as they are needed;  (2)
  95 %  Chooses a maximum depth for the tree as a function of the desired
  96 %  number of colors in the output image (currently log2(colormap size)).
  97 %
  98 %  For each pixel in the input image, storage_class scans downward from
  99 %  the root of the color description tree.  At each level of the tree it
 100 %  identifies the single node which represents a cube in RGB space
 101 %  containing the pixel's color.  It updates the following data for each
 102 %  such node:
 103 %
 104 %    n1: Number of pixels whose color is contained in the RGB cube which
 105 %    this node represents;
 106 %
 107 %    n2: Number of pixels whose color is not represented in a node at
 108 %    lower depth in the tree;  initially,  n2 = 0 for all nodes except
 109 %    leaves of the tree.
 110 %
 111 %    Sr, Sg, Sb: Sums of the red, green, and blue component values for all
 112 %    pixels not classified at a lower depth. The combination of these sums
 113 %    and n2 will ultimately characterize the mean color of a set of pixels
 114 %    represented by this node.
 115 %
 116 %    E: the distance squared in RGB space between each pixel contained
 117 %    within a node and the nodes' center.  This represents the
 118 %    quantization error for a node.
 119 %
 120 %  Reduction repeatedly prunes the tree until the number of nodes with n2
 121 %  > 0 is less than or equal to the maximum number of colors allowed in
 122 %  the output image.  On any given iteration over the tree, it selects
 123 %  those nodes whose E count is minimal for pruning and merges their color
 124 %  statistics upward. It uses a pruning threshold, Ep, to govern node
 125 %  selection as follows:
 126 %
 127 %    Ep = 0
 128 %    while number of nodes with (n2 > 0) > required maximum number of colors
 129 %      prune all nodes such that E <= Ep
 130 %      Set Ep to minimum E in remaining nodes
 131 %
 132 %  This has the effect of minimizing any quantization error when merging
 133 %  two nodes together.
 134 %
 135 %  When a node to be pruned has offspring, the pruning procedure invokes
 136 %  itself recursively in order to prune the tree from the leaves upward.
 137 %  n2,  Sr, Sg,  and  Sb in a node being pruned are always added to the
 138 %  corresponding data in that node's parent.  This retains the pruned
 139 %  node's color characteristics for later averaging.
 140 %
 141 %  For each node, n2 pixels exist for which that node represents the
 142 %  smallest volume in RGB space containing those pixel's colors.  When n2
 143 %  > 0 the node will uniquely define a color in the output image. At the
 144 %  beginning of reduction,  n2 = 0  for all nodes except a the leaves of
 145 %  the tree which represent colors present in the input image.
 146 %
 147 %  The other pixel count, n1, indicates the total number of colors within
 148 %  the cubic volume which the node represents.  This includes n1 - n2
 149 %  pixels whose colors should be defined by nodes at a lower level in the
 150 %  tree.
 151 %
 152 %  Assignment generates the output image from the pruned tree.  The output
 153 %  image consists of two parts: (1)  A color map, which is an array of
 154 %  color descriptions (RGB triples) for each color present in the output
 155 %  image;  (2)  A pixel array, which represents each pixel as an index
 156 %  into the color map array.
 157 %
 158 %  First, the assignment phase makes one pass over the pruned color
 159 %  description tree to establish the image's color map.  For each node
 160 %  with n2  > 0, it divides Sr, Sg, and Sb by n2 .  This produces the mean
 161 %  color of all pixels that classify no lower than this node.  Each of
 162 %  these colors becomes an entry in the color map.
 163 %
 164 %  Finally,  the assignment phase reclassifies each pixel in the pruned
 165 %  tree to identify the deepest node containing the pixel's color.  The
 166 %  pixel's value in the pixel array becomes the index of this node's mean
 167 %  color in the color map.
 168 %
 169 %  This method is based on a similar algorithm written by Paul Raveling.
 170 %
 171 */
 172 \f
 173 /*
 174   Include declarations.
 175 */
 176 #include "MagickCore/studio.h"
 177 #include "MagickCore/attribute.h"
 178 #include "MagickCore/cache-view.h"
 179 #include "MagickCore/color.h"
 180 #include "MagickCore/color-private.h"
 181 #include "MagickCore/colormap.h"
 182 #include "MagickCore/colorspace.h"
 183 #include "MagickCore/colorspace-private.h"
 184 #include "MagickCore/enhance.h"
 185 #include "MagickCore/exception.h"
 186 #include "MagickCore/exception-private.h"
 187 #include "MagickCore/histogram.h"
 188 #include "MagickCore/image.h"
 189 #include "MagickCore/image-private.h"
 190 #include "MagickCore/list.h"
 191 #include "MagickCore/memory_.h"
 192 #include "MagickCore/memory-private.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 _DoublePixelPacket
 222 {
 223   double
 224     red,
 225     green,
 226     blue,
 227     alpha;
 228 } DoublePixelPacket;
 229
 230 typedef struct _NodeInfo
 231 {
 232   struct _NodeInfo
 233     *parent,
 234     *child[16];
 235
 236   MagickSizeType
 237     number_unique;
 238
 239   DoublePixelPacket
 240     total_color;
 241
 242   double
 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   DoublePixelPacket
 276     target;
 277
 278   double
 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   MemoryInfo
 295     *memory_info;
 296
 297   ssize_t
 298     *cache;
 299
 300   DoublePixelPacket
 301     error[ErrorQueueLength];
 302
 303   double
 304     weights[ErrorQueueLength];
 305
 306   QuantizeInfo
 307     *quantize_info;
 308
 309   MagickBooleanType
 310     associate_alpha;
 311
 312   ssize_t
 313     x,
 314     y;
 315
 316   size_t
 317     depth;
 318
 319   MagickOffsetType
 320     offset;
 321
 322   MagickSizeType
 323     span;
 324 } CubeInfo;
 325 \f
 326 /*
 327   Method prototypes.
 328 */
 329 static CubeInfo
 330   *GetCubeInfo(const QuantizeInfo *,const size_t,const size_t);
 331
 332 static NodeInfo
 333   *GetNodeInfo(CubeInfo *,const size_t,const size_t,NodeInfo *);
 334
 335 static MagickBooleanType
 336   AssignImageColors(Image *,CubeInfo *,ExceptionInfo *),
 337   ClassifyImageColors(CubeInfo *,const Image *,ExceptionInfo *),
 338   DitherImage(Image *,CubeInfo *,ExceptionInfo *),
 339   SetGrayscaleImage(Image *,ExceptionInfo *);
 340
 341 static size_t
 342   DefineImageColormap(Image *,CubeInfo *,NodeInfo *);
 343
 344 static void
 345   ClosestColor(const Image *,CubeInfo *,const NodeInfo *),
 346   DestroyCubeInfo(CubeInfo *),
 347   PruneLevel(CubeInfo *,const NodeInfo *),
 348   PruneToCubeDepth(CubeInfo *,const NodeInfo *),
 349   ReduceImageColors(const Image *,CubeInfo *);
 350 \f
 351 /*
 352 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 353 %                                                                             %
 354 %                                                                             %
 355 %                                                                             %
 356 %   A c q u i r e Q u a n t i z e I n f o                                     %
 357 %                                                                             %
 358 %                                                                             %
 359 %                                                                             %
 360 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 361 %
 362 %  AcquireQuantizeInfo() allocates the QuantizeInfo structure.
 363 %
 364 %  The format of the AcquireQuantizeInfo method is:
 365 %
 366 %      QuantizeInfo *AcquireQuantizeInfo(const ImageInfo *image_info)
 367 %
 368 %  A description of each parameter follows:
 369 %
 370 %    o image_info: the image info.
 371 %
 372 */
 373 MagickExport QuantizeInfo *AcquireQuantizeInfo(const ImageInfo *image_info)
 374 {
 375   QuantizeInfo
 376     *quantize_info;
 377
 378   quantize_info=(QuantizeInfo *) AcquireCriticalMemory(sizeof(*quantize_info));
 379   GetQuantizeInfo(quantize_info);
 380   if (image_info != (ImageInfo *) NULL)
 381     {
 382       const char
 383         *option;
 384
 385       quantize_info->dither_method=image_info->dither == MagickFalse ?
 386         NoDitherMethod : RiemersmaDitherMethod;
 387       option=GetImageOption(image_info,"dither");
 388       if (option != (const char *) NULL)
 389         quantize_info->dither_method=(DitherMethod) ParseCommandOption(
 390           MagickDitherOptions,MagickFalse,option);
 391       quantize_info->measure_error=image_info->verbose;
 392     }
 393   return(quantize_info);
 394 }
 395 \f
 396 /*
 397 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 398 %                                                                             %
 399 %                                                                             %
 400 %                                                                             %
 401 +   A s s i g n I m a g e C o l o r s                                         %
 402 %                                                                             %
 403 %                                                                             %
 404 %                                                                             %
 405 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 406 %
 407 %  AssignImageColors() generates the output image from the pruned tree.  The
 408 %  output image consists of two parts: (1)  A color map, which is an array
 409 %  of color descriptions (RGB triples) for each color present in the
 410 %  output image;  (2)  A pixel array, which represents each pixel as an
 411 %  index into the color map array.
 412 %
 413 %  First, the assignment phase makes one pass over the pruned color
 414 %  description tree to establish the image's color map.  For each node
 415 %  with n2  > 0, it divides Sr, Sg, and Sb by n2 .  This produces the mean
 416 %  color of all pixels that classify no lower than this node.  Each of
 417 %  these colors becomes an entry in the color map.
 418 %
 419 %  Finally,  the assignment phase reclassifies each pixel in the pruned
 420 %  tree to identify the deepest node containing the pixel's color.  The
 421 %  pixel's value in the pixel array becomes the index of this node's mean
 422 %  color in the color map.
 423 %
 424 %  The format of the AssignImageColors() method is:
 425 %
 426 %      MagickBooleanType AssignImageColors(Image *image,CubeInfo *cube_info)
 427 %
 428 %  A description of each parameter follows.
 429 %
 430 %    o image: the image.
 431 %
 432 %    o cube_info: A pointer to the Cube structure.
 433 %
 434 */
 435
 436 static inline void AssociateAlphaPixel(const Image *image,
 437   const CubeInfo *cube_info,const Quantum *pixel,DoublePixelPacket *alpha_pixel)
 438 {
 439   double
 440     alpha;
 441
 442   if ((cube_info->associate_alpha == MagickFalse) ||
 443       (GetPixelAlpha(image,pixel) == OpaqueAlpha))
 444     {
 445       alpha_pixel->red=(double) GetPixelRed(image,pixel);
 446       alpha_pixel->green=(double) GetPixelGreen(image,pixel);
 447       alpha_pixel->blue=(double) GetPixelBlue(image,pixel);
 448       alpha_pixel->alpha=(double) GetPixelAlpha(image,pixel);
 449       return;
 450     }
 451   alpha=(double) (QuantumScale*GetPixelAlpha(image,pixel));
 452   alpha_pixel->red=alpha*GetPixelRed(image,pixel);
 453   alpha_pixel->green=alpha*GetPixelGreen(image,pixel);
 454   alpha_pixel->blue=alpha*GetPixelBlue(image,pixel);
 455   alpha_pixel->alpha=(double) GetPixelAlpha(image,pixel);
 456 }
 457
 458 static inline void AssociateAlphaPixelInfo(const CubeInfo *cube_info,
 459   const PixelInfo *pixel,DoublePixelPacket *alpha_pixel)
 460 {
 461   double
 462     alpha;
 463
 464   if ((cube_info->associate_alpha == MagickFalse) ||
 465       (pixel->alpha == OpaqueAlpha))
 466     {
 467       alpha_pixel->red=(double) pixel->red;
 468       alpha_pixel->green=(double) pixel->green;
 469       alpha_pixel->blue=(double) pixel->blue;
 470       alpha_pixel->alpha=(double) pixel->alpha;
 471       return;
 472     }
 473   alpha=(double) (QuantumScale*pixel->alpha);
 474   alpha_pixel->red=alpha*pixel->red;
 475   alpha_pixel->green=alpha*pixel->green;
 476   alpha_pixel->blue=alpha*pixel->blue;
 477   alpha_pixel->alpha=(double) pixel->alpha;
 478 }
 479
 480 static inline size_t ColorToNodeId(const CubeInfo *cube_info,
 481   const DoublePixelPacket *pixel,size_t index)
 482 {
 483   size_t
 484     id;
 485
 486   id=(size_t) (((ScaleQuantumToChar(ClampPixel(pixel->red)) >> index) & 0x01) |
 487     ((ScaleQuantumToChar(ClampPixel(pixel->green)) >> index) & 0x01) << 1 |
 488     ((ScaleQuantumToChar(ClampPixel(pixel->blue)) >> index) & 0x01) << 2);
 489   if (cube_info->associate_alpha != MagickFalse)
 490     id|=((ScaleQuantumToChar(ClampPixel(pixel->alpha)) >> index) & 0x1) << 3;
 491   return(id);
 492 }
 493
 494 static MagickBooleanType AssignImageColors(Image *image,CubeInfo *cube_info,
 495   ExceptionInfo *exception)
 496 {
 497 #define AssignImageTag  "Assign/Image"
 498
 499   ssize_t
 500     y;
 501
 502   /*
 503     Allocate image colormap.
 504   */
 505   if ((cube_info->quantize_info->colorspace != UndefinedColorspace) &&
 506       (cube_info->quantize_info->colorspace != CMYKColorspace))
 507     (void) TransformImageColorspace(image,cube_info->quantize_info->colorspace,
 508       exception);
 509   else
 510     if (IssRGBCompatibleColorspace(image->colorspace) == MagickFalse)
 511       (void) TransformImageColorspace(image,sRGBColorspace,exception);
 512   if (AcquireImageColormap(image,cube_info->colors,exception) == MagickFalse)
 513     ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
 514       image->filename);
 515   image->colors=0;
 516   cube_info->transparent_pixels=0;
 517   cube_info->transparent_index=(-1);
 518   (void) DefineImageColormap(image,cube_info,cube_info->root);
 519   /*
 520     Create a reduced color image.
 521   */
 522   if (cube_info->quantize_info->dither_method != NoDitherMethod)
 523     (void) DitherImage(image,cube_info,exception);
 524   else
 525     {
 526       CacheView
 527         *image_view;
 528
 529       MagickBooleanType
 530         status;
 531
 532       status=MagickTrue;
 533       image_view=AcquireAuthenticCacheView(image,exception);
 534 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 535       #pragma omp parallel for schedule(static,4) shared(status) \
 536         magick_number_threads(image,image,image->rows,1)
 537 #endif
 538       for (y=0; y < (ssize_t) image->rows; y++)
 539       {
 540         CubeInfo
 541           cube;
 542
 543         register Quantum
 544           *magick_restrict q;
 545
 546         register ssize_t
 547           x;
 548
 549         ssize_t
 550           count;
 551
 552         if (status == MagickFalse)
 553           continue;
 554         q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,
 555           exception);
 556         if (q == (Quantum *) NULL)
 557           {
 558             status=MagickFalse;
 559             continue;
 560           }
 561         cube=(*cube_info);
 562         for (x=0; x < (ssize_t) image->columns; x+=count)
 563         {
 564           DoublePixelPacket
 565             pixel;
 566
 567           register const NodeInfo
 568             *node_info;
 569
 570           register ssize_t
 571             i;
 572
 573           size_t
 574             id,
 575             index;
 576
 577           /*
 578             Identify the deepest node containing the pixel's color.
 579           */
 580           for (count=1; (x+count) < (ssize_t) image->columns; count++)
 581           {
 582             PixelInfo
 583               packet;
 584
 585             GetPixelInfoPixel(image,q+count*GetPixelChannels(image),&packet);
 586             if (IsPixelEquivalent(image,q,&packet) == MagickFalse)
 587               break;
 588           }
 589           AssociateAlphaPixel(image,&cube,q,&pixel);
 590           node_info=cube.root;
 591           for (index=MaxTreeDepth-1; (ssize_t) index > 0; index--)
 592           {
 593             id=ColorToNodeId(&cube,&pixel,index);
 594             if (node_info->child[id] == (NodeInfo *) NULL)
 595               break;
 596             node_info=node_info->child[id];
 597           }
 598           /*
 599             Find closest color among siblings and their children.
 600           */
 601           cube.target=pixel;
 602           cube.distance=(double) (4.0*(QuantumRange+1.0)*(QuantumRange+1.0)+
 603             1.0);
 604           ClosestColor(image,&cube,node_info->parent);
 605           index=cube.color_number;
 606           for (i=0; i < (ssize_t) count; i++)
 607           {
 608             if (image->storage_class == PseudoClass)
 609               SetPixelIndex(image,(Quantum) index,q);
 610             if (cube.quantize_info->measure_error == MagickFalse)
 611               {
 612                 SetPixelRed(image,ClampToQuantum(
 613                   image->colormap[index].red),q);
 614                 SetPixelGreen(image,ClampToQuantum(
 615                   image->colormap[index].green),q);
 616                 SetPixelBlue(image,ClampToQuantum(
 617                   image->colormap[index].blue),q);
 618                 if (cube.associate_alpha != MagickFalse)
 619                   SetPixelAlpha(image,ClampToQuantum(
 620                     image->colormap[index].alpha),q);
 621               }
 622             q+=GetPixelChannels(image);
 623           }
 624         }
 625         if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
 626           status=MagickFalse;
 627         if (image->progress_monitor != (MagickProgressMonitor) NULL)
 628           {
 629             MagickBooleanType
 630               proceed;
 631
 632 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 633             #pragma omp critical (MagickCore_AssignImageColors)
 634 #endif
 635             proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) y,
 636               image->rows);
 637             if (proceed == MagickFalse)
 638               status=MagickFalse;
 639           }
 640       }
 641       image_view=DestroyCacheView(image_view);
 642     }
 643   if (cube_info->quantize_info->measure_error != MagickFalse)
 644     (void) GetImageQuantizeError(image,exception);
 645   if ((cube_info->quantize_info->number_colors == 2) &&
 646       ((cube_info->quantize_info->colorspace == LinearGRAYColorspace) ||
 647        (cube_info->quantize_info->colorspace == GRAYColorspace)))
 648     {
 649       double
 650         intensity;
 651
 652       /*
 653         Monochrome image.
 654       */
 655       intensity=0.0;
 656       if ((image->colors > 1) &&
 657           (GetPixelInfoLuma(image->colormap+0) >
 658            GetPixelInfoLuma(image->colormap+1)))
 659         intensity=(double) QuantumRange;
 660       image->colormap[0].red=intensity;
 661       image->colormap[0].green=intensity;
 662       image->colormap[0].blue=intensity;
 663       if (image->colors > 1)
 664         {
 665           image->colormap[1].red=(double) QuantumRange-intensity;
 666           image->colormap[1].green=(double) QuantumRange-intensity;
 667           image->colormap[1].blue=(double) QuantumRange-intensity;
 668         }
 669     }
 670   (void) SyncImage(image,exception);
 671   if ((cube_info->quantize_info->colorspace != UndefinedColorspace) &&
 672       (cube_info->quantize_info->colorspace != CMYKColorspace))
 673     (void) TransformImageColorspace((Image *) image,sRGBColorspace,exception);
 674   return(MagickTrue);
 675 }
 676 \f
 677 /*
 678 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 679 %                                                                             %
 680 %                                                                             %
 681 %                                                                             %
 682 +   C l a s s i f y I m a g e C o l o r s                                     %
 683 %                                                                             %
 684 %                                                                             %
 685 %                                                                             %
 686 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 687 %
 688 %  ClassifyImageColors() begins by initializing a color description tree
 689 %  of sufficient depth to represent each possible input color in a leaf.
 690 %  However, it is impractical to generate a fully-formed color
 691 %  description tree in the storage_class phase for realistic values of
 692 %  Cmax.  If colors components in the input image are quantized to k-bit
 693 %  precision, so that Cmax= 2k-1, the tree would need k levels below the
 694 %  root node to allow representing each possible input color in a leaf.
 695 %  This becomes prohibitive because the tree's total number of nodes is
 696 %  1 + sum(i=1,k,8k).
 697 %
 698 %  A complete tree would require 19,173,961 nodes for k = 8, Cmax = 255.
 699 %  Therefore, to avoid building a fully populated tree, QUANTIZE: (1)
 700 %  Initializes data structures for nodes only as they are needed;  (2)
 701 %  Chooses a maximum depth for the tree as a function of the desired
 702 %  number of colors in the output image (currently log2(colormap size)).
 703 %
 704 %  For each pixel in the input image, storage_class scans downward from
 705 %  the root of the color description tree.  At each level of the tree it
 706 %  identifies the single node which represents a cube in RGB space
 707 %  containing It updates the following data for each such node:
 708 %
 709 %    n1 : Number of pixels whose color is contained in the RGB cube
 710 %    which this node represents;
 711 %
 712 %    n2 : Number of pixels whose color is not represented in a node at
 713 %    lower depth in the tree;  initially,  n2 = 0 for all nodes except
 714 %    leaves of the tree.
 715 %
 716 %    Sr, Sg, Sb : Sums of the red, green, and blue component values for
 717 %    all pixels not classified at a lower depth. The combination of
 718 %    these sums and n2 will ultimately characterize the mean color of a
 719 %    set of pixels represented by this node.
 720 %
 721 %    E: the distance squared in RGB space between each pixel contained
 722 %    within a node and the nodes' center.  This represents the quantization
 723 %    error for a node.
 724 %
 725 %  The format of the ClassifyImageColors() method is:
 726 %
 727 %      MagickBooleanType ClassifyImageColors(CubeInfo *cube_info,
 728 %        const Image *image,ExceptionInfo *exception)
 729 %
 730 %  A description of each parameter follows.
 731 %
 732 %    o cube_info: A pointer to the Cube structure.
 733 %
 734 %    o image: the image.
 735 %
 736 */
 737
 738 static inline void SetAssociatedAlpha(const Image *image,CubeInfo *cube_info)
 739 {
 740   MagickBooleanType
 741     associate_alpha;
 742
 743   associate_alpha=image->alpha_trait == BlendPixelTrait ? MagickTrue :
 744     MagickFalse;
 745   if ((cube_info->quantize_info->number_colors == 2) &&
 746       ((cube_info->quantize_info->colorspace == LinearGRAYColorspace) ||
 747        (cube_info->quantize_info->colorspace == GRAYColorspace)))
 748     associate_alpha=MagickFalse;
 749   cube_info->associate_alpha=associate_alpha;
 750 }
 751
 752 static MagickBooleanType ClassifyImageColors(CubeInfo *cube_info,
 753   const Image *image,ExceptionInfo *exception)
 754 {
 755 #define ClassifyImageTag  "Classify/Image"
 756
 757   CacheView
 758     *image_view;
 759
 760   DoublePixelPacket
 761     error,
 762     mid,
 763     midpoint,
 764     pixel;
 765
 766   MagickBooleanType
 767     proceed;
 768
 769   double
 770     bisect;
 771
 772   NodeInfo
 773     *node_info;
 774
 775   size_t
 776     count,
 777     id,
 778     index,
 779     level;
 780
 781   ssize_t
 782     y;
 783
 784   /*
 785     Classify the first cube_info->maximum_colors colors to a tree depth of 8.
 786   */
 787   SetAssociatedAlpha(image,cube_info);
 788   if ((cube_info->quantize_info->colorspace != UndefinedColorspace) &&
 789       (cube_info->quantize_info->colorspace != CMYKColorspace))
 790     (void) TransformImageColorspace((Image *) image,
 791       cube_info->quantize_info->colorspace,exception);
 792   else
 793     if (IssRGBCompatibleColorspace(image->colorspace) == MagickFalse)
 794       (void) TransformImageColorspace((Image *) image,sRGBColorspace,exception);
 795   midpoint.red=(double) QuantumRange/2.0;
 796   midpoint.green=(double) QuantumRange/2.0;
 797   midpoint.blue=(double) QuantumRange/2.0;
 798   midpoint.alpha=(double) QuantumRange/2.0;
 799   error.alpha=0.0;
 800   image_view=AcquireVirtualCacheView(image,exception);
 801   for (y=0; y < (ssize_t) image->rows; y++)
 802   {
 803     register const Quantum
 804       *magick_restrict p;
 805
 806     register ssize_t
 807       x;
 808
 809     p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
 810     if (p == (const Quantum *) NULL)
 811       break;
 812     if (cube_info->nodes > MaxNodes)
 813       {
 814         /*
 815           Prune one level if the color tree is too large.
 816         */
 817         PruneLevel(cube_info,cube_info->root);
 818         cube_info->depth--;
 819       }
 820     for (x=0; x < (ssize_t) image->columns; x+=(ssize_t) count)
 821     {
 822       /*
 823         Start at the root and descend the color cube tree.
 824       */
 825       for (count=1; (x+(ssize_t) count) < (ssize_t) image->columns; count++)
 826       {
 827         PixelInfo
 828           packet;
 829
 830         GetPixelInfoPixel(image,p+count*GetPixelChannels(image),&packet);
 831         if (IsPixelEquivalent(image,p,&packet) == MagickFalse)
 832           break;
 833       }
 834       AssociateAlphaPixel(image,cube_info,p,&pixel);
 835       index=MaxTreeDepth-1;
 836       bisect=((double) QuantumRange+1.0)/2.0;
 837       mid=midpoint;
 838       node_info=cube_info->root;
 839       for (level=1; level <= MaxTreeDepth; level++)
 840       {
 841         double
 842           distance;
 843
 844         bisect*=0.5;
 845         id=ColorToNodeId(cube_info,&pixel,index);
 846         mid.red+=(id & 1) != 0 ? bisect : -bisect;
 847         mid.green+=(id & 2) != 0 ? bisect : -bisect;
 848         mid.blue+=(id & 4) != 0 ? bisect : -bisect;
 849         mid.alpha+=(id & 8) != 0 ? bisect : -bisect;
 850         if (node_info->child[id] == (NodeInfo *) NULL)
 851           {
 852             /*
 853               Set colors of new node to contain pixel.
 854             */
 855             node_info->child[id]=GetNodeInfo(cube_info,id,level,node_info);
 856             if (node_info->child[id] == (NodeInfo *) NULL)
 857               {
 858                 (void) ThrowMagickException(exception,GetMagickModule(),
 859                   ResourceLimitError,"MemoryAllocationFailed","`%s'",
 860                   image->filename);
 861                 continue;
 862               }
 863             if (level == MaxTreeDepth)
 864               cube_info->colors++;
 865           }
 866         /*
 867           Approximate the quantization error represented by this node.
 868         */
 869         node_info=node_info->child[id];
 870         error.red=QuantumScale*(pixel.red-mid.red);
 871         error.green=QuantumScale*(pixel.green-mid.green);
 872         error.blue=QuantumScale*(pixel.blue-mid.blue);
 873         if (cube_info->associate_alpha != MagickFalse)
 874           error.alpha=QuantumScale*(pixel.alpha-mid.alpha);
 875         distance=(double) (error.red*error.red+error.green*error.green+
 876           error.blue*error.blue+error.alpha*error.alpha);
 877         if (IsNaN(distance))
 878           distance=0.0;
 879         node_info->quantize_error+=count*sqrt(distance);
 880         cube_info->root->quantize_error+=node_info->quantize_error;
 881         index--;
 882       }
 883       /*
 884         Sum RGB for this leaf for later derivation of the mean cube color.
 885       */
 886       node_info->number_unique+=count;
 887       node_info->total_color.red+=count*QuantumScale*ClampPixel(pixel.red);
 888       node_info->total_color.green+=count*QuantumScale*ClampPixel(pixel.green);
 889       node_info->total_color.blue+=count*QuantumScale*ClampPixel(pixel.blue);
 890       if (cube_info->associate_alpha != MagickFalse)
 891         node_info->total_color.alpha+=count*QuantumScale*
 892           ClampPixel(pixel.alpha);
 893       else
 894         node_info->total_color.alpha+=count*QuantumScale*
 895           ClampPixel(OpaqueAlpha);
 896       p+=count*GetPixelChannels(image);
 897     }
 898     if (cube_info->colors > cube_info->maximum_colors)
 899       {
 900         PruneToCubeDepth(cube_info,cube_info->root);
 901         break;
 902       }
 903     proceed=SetImageProgress(image,ClassifyImageTag,(MagickOffsetType) y,
 904       image->rows);
 905     if (proceed == MagickFalse)
 906       break;
 907   }
 908   for (y++; y < (ssize_t) image->rows; y++)
 909   {
 910     register const Quantum
 911       *magick_restrict p;
 912
 913     register ssize_t
 914       x;
 915
 916     p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
 917     if (p == (const Quantum *) NULL)
 918       break;
 919     if (cube_info->nodes > MaxNodes)
 920       {
 921         /*
 922           Prune one level if the color tree is too large.
 923         */
 924         PruneLevel(cube_info,cube_info->root);
 925         cube_info->depth--;
 926       }
 927     for (x=0; x < (ssize_t) image->columns; x+=(ssize_t) count)
 928     {
 929       /*
 930         Start at the root and descend the color cube tree.
 931       */
 932       for (count=1; (x+(ssize_t) count) < (ssize_t) image->columns; count++)
 933       {
 934         PixelInfo
 935           packet;
 936
 937         GetPixelInfoPixel(image,p+count*GetPixelChannels(image),&packet);
 938         if (IsPixelEquivalent(image,p,&packet) == MagickFalse)
 939           break;
 940       }
 941       AssociateAlphaPixel(image,cube_info,p,&pixel);
 942       index=MaxTreeDepth-1;
 943       bisect=((double) QuantumRange+1.0)/2.0;
 944       mid=midpoint;
 945       node_info=cube_info->root;
 946       for (level=1; level <= cube_info->depth; level++)
 947       {
 948         double
 949           distance;
 950
 951         bisect*=0.5;
 952         id=ColorToNodeId(cube_info,&pixel,index);
 953         mid.red+=(id & 1) != 0 ? bisect : -bisect;
 954         mid.green+=(id & 2) != 0 ? bisect : -bisect;
 955         mid.blue+=(id & 4) != 0 ? bisect : -bisect;
 956         mid.alpha+=(id & 8) != 0 ? bisect : -bisect;
 957         if (node_info->child[id] == (NodeInfo *) NULL)
 958           {
 959             /*
 960               Set colors of new node to contain pixel.
 961             */
 962             node_info->child[id]=GetNodeInfo(cube_info,id,level,node_info);
 963             if (node_info->child[id] == (NodeInfo *) NULL)
 964               {
 965                 (void) ThrowMagickException(exception,GetMagickModule(),
 966                   ResourceLimitError,"MemoryAllocationFailed","%s",
 967                   image->filename);
 968                 continue;
 969               }
 970             if (level == cube_info->depth)
 971               cube_info->colors++;
 972           }
 973         /*
 974           Approximate the quantization error represented by this node.
 975         */
 976         node_info=node_info->child[id];
 977         error.red=QuantumScale*(pixel.red-mid.red);
 978         error.green=QuantumScale*(pixel.green-mid.green);
 979         error.blue=QuantumScale*(pixel.blue-mid.blue);
 980         if (cube_info->associate_alpha != MagickFalse)
 981           error.alpha=QuantumScale*(pixel.alpha-mid.alpha);
 982         distance=(double) (error.red*error.red+error.green*error.green+
 983           error.blue*error.blue+error.alpha*error.alpha);
 984         if (IsNaN(distance) != MagickFalse)
 985           distance=0.0;
 986         node_info->quantize_error+=count*sqrt(distance);
 987         cube_info->root->quantize_error+=node_info->quantize_error;
 988         index--;
 989       }
 990       /*
 991         Sum RGB for this leaf for later derivation of the mean cube color.
 992       */
 993       node_info->number_unique+=count;
 994       node_info->total_color.red+=count*QuantumScale*ClampPixel(pixel.red);
 995       node_info->total_color.green+=count*QuantumScale*ClampPixel(pixel.green);
 996       node_info->total_color.blue+=count*QuantumScale*ClampPixel(pixel.blue);
 997       if (cube_info->associate_alpha != MagickFalse)
 998         node_info->total_color.alpha+=count*QuantumScale*
 999           ClampPixel(pixel.alpha);
1000       else
1001         node_info->total_color.alpha+=count*QuantumScale*
1002           ClampPixel(OpaqueAlpha);
1003       p+=count*GetPixelChannels(image);
1004     }
1005     proceed=SetImageProgress(image,ClassifyImageTag,(MagickOffsetType) y,
1006       image->rows);
1007     if (proceed == MagickFalse)
1008       break;
1009   }
1010   image_view=DestroyCacheView(image_view);
1011   if ((cube_info->quantize_info->colorspace != UndefinedColorspace) &&
1012       (cube_info->quantize_info->colorspace != CMYKColorspace))
1013     (void) TransformImageColorspace((Image *) image,sRGBColorspace,exception);
1014   return(y < (ssize_t) image->rows ? MagickFalse : MagickTrue);
1015 }
1016 \f
1017 /*
1018 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1019 %                                                                             %
1020 %                                                                             %
1021 %                                                                             %
1022 %   C l o n e Q u a n t i z e I n f o                                         %
1023 %                                                                             %
1024 %                                                                             %
1025 %                                                                             %
1026 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1027 %
1028 %  CloneQuantizeInfo() makes a duplicate of the given quantize info structure,
1029 %  or if quantize info is NULL, a new one.
1030 %
1031 %  The format of the CloneQuantizeInfo method is:
1032 %
1033 %      QuantizeInfo *CloneQuantizeInfo(const QuantizeInfo *quantize_info)
1034 %
1035 %  A description of each parameter follows:
1036 %
1037 %    o clone_info: Method CloneQuantizeInfo returns a duplicate of the given
1038 %      quantize info, or if image info is NULL a new one.
1039 %
1040 %    o quantize_info: a structure of type info.
1041 %
1042 */
1043 MagickExport QuantizeInfo *CloneQuantizeInfo(const QuantizeInfo *quantize_info)
1044 {
1045   QuantizeInfo
1046     *clone_info;
1047
1048   clone_info=(QuantizeInfo *) AcquireCriticalMemory(sizeof(*clone_info));
1049   GetQuantizeInfo(clone_info);
1050   if (quantize_info == (QuantizeInfo *) NULL)
1051     return(clone_info);
1052   clone_info->number_colors=quantize_info->number_colors;
1053   clone_info->tree_depth=quantize_info->tree_depth;
1054   clone_info->dither_method=quantize_info->dither_method;
1055   clone_info->colorspace=quantize_info->colorspace;
1056   clone_info->measure_error=quantize_info->measure_error;
1057   return(clone_info);
1058 }
1059 \f
1060 /*
1061 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1062 %                                                                             %
1063 %                                                                             %
1064 %                                                                             %
1065 +   C l o s e s t C o l o r                                                   %
1066 %                                                                             %
1067 %                                                                             %
1068 %                                                                             %
1069 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1070 %
1071 %  ClosestColor() traverses the color cube tree at a particular node and
1072 %  determines which colormap entry best represents the input color.
1073 %
1074 %  The format of the ClosestColor method is:
1075 %
1076 %      void ClosestColor(const Image *image,CubeInfo *cube_info,
1077 %        const NodeInfo *node_info)
1078 %
1079 %  A description of each parameter follows.
1080 %
1081 %    o image: the image.
1082 %
1083 %    o cube_info: A pointer to the Cube structure.
1084 %
1085 %    o node_info: the address of a structure of type NodeInfo which points to a
1086 %      node in the color cube tree that is to be pruned.
1087 %
1088 */
1089 static void ClosestColor(const Image *image,CubeInfo *cube_info,
1090   const NodeInfo *node_info)
1091 {
1092   register ssize_t
1093     i;
1094
1095   size_t
1096     number_children;
1097
1098   /*
1099     Traverse any children.
1100   */
1101   number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
1102   for (i=0; i < (ssize_t) number_children; i++)
1103     if (node_info->child[i] != (NodeInfo *) NULL)
1104       ClosestColor(image,cube_info,node_info->child[i]);
1105   if (node_info->number_unique != 0)
1106     {
1107       double
1108         pixel;
1109
1110       register double
1111         alpha,
1112         beta,
1113         distance;
1114
1115       register DoublePixelPacket
1116         *magick_restrict q;
1117
1118       register PixelInfo
1119         *magick_restrict p;
1120
1121       /*
1122         Determine if this color is "closest".
1123       */
1124       p=image->colormap+node_info->color_number;
1125       q=(&cube_info->target);
1126       alpha=1.0;
1127       beta=1.0;
1128       if (cube_info->associate_alpha != MagickFalse)
1129         {
1130           alpha=(double) (QuantumScale*p->alpha);
1131           beta=(double) (QuantumScale*q->alpha);
1132         }
1133       pixel=alpha*p->red-beta*q->red;
1134       distance=pixel*pixel;
1135       if (distance <= cube_info->distance)
1136         {
1137           pixel=alpha*p->green-beta*q->green;
1138           distance+=pixel*pixel;
1139           if (distance <= cube_info->distance)
1140             {
1141               pixel=alpha*p->blue-beta*q->blue;
1142               distance+=pixel*pixel;
1143               if (distance <= cube_info->distance)
1144                 {
1145                   if (cube_info->associate_alpha != MagickFalse)
1146                     {
1147                       pixel=p->alpha-q->alpha;
1148                       distance+=pixel*pixel;
1149                     }
1150                   if (distance <= cube_info->distance)
1151                     {
1152                       cube_info->distance=distance;
1153                       cube_info->color_number=node_info->color_number;
1154                     }
1155                 }
1156             }
1157         }
1158     }
1159 }
1160 \f
1161 /*
1162 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1163 %                                                                             %
1164 %                                                                             %
1165 %                                                                             %
1166 %   C o m p r e s s I m a g e C o l o r m a p                                 %
1167 %                                                                             %
1168 %                                                                             %
1169 %                                                                             %
1170 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1171 %
1172 %  CompressImageColormap() compresses an image colormap by removing any
1173 %  duplicate or unused color entries.
1174 %
1175 %  The format of the CompressImageColormap method is:
1176 %
1177 %      MagickBooleanType CompressImageColormap(Image *image,
1178 %        ExceptionInfo *exception)
1179 %
1180 %  A description of each parameter follows:
1181 %
1182 %    o image: the image.
1183 %
1184 %    o exception: return any errors or warnings in this structure.
1185 %
1186 */
1187 MagickExport MagickBooleanType CompressImageColormap(Image *image,
1188   ExceptionInfo *exception)
1189 {
1190   QuantizeInfo
1191     quantize_info;
1192
1193   assert(image != (Image *) NULL);
1194   assert(image->signature == MagickCoreSignature);
1195   if (image->debug != MagickFalse)
1196     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1197   if (IsPaletteImage(image) == MagickFalse)
1198     return(MagickFalse);
1199   GetQuantizeInfo(&quantize_info);
1200   quantize_info.number_colors=image->colors;
1201   quantize_info.tree_depth=MaxTreeDepth;
1202   return(QuantizeImage(&quantize_info,image,exception));
1203 }
1204 \f
1205 /*
1206 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1207 %                                                                             %
1208 %                                                                             %
1209 %                                                                             %
1210 +   D e f i n e I m a g e C o l o r m a p                                     %
1211 %                                                                             %
1212 %                                                                             %
1213 %                                                                             %
1214 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1215 %
1216 %  DefineImageColormap() traverses the color cube tree and notes each colormap
1217 %  entry.  A colormap entry is any node in the color cube tree where the
1218 %  of unique colors is not zero.  DefineImageColormap() returns the number of
1219 %  colors in the image colormap.
1220 %
1221 %  The format of the DefineImageColormap method is:
1222 %
1223 %      size_t DefineImageColormap(Image *image,CubeInfo *cube_info,
1224 %        NodeInfo *node_info)
1225 %
1226 %  A description of each parameter follows.
1227 %
1228 %    o image: the image.
1229 %
1230 %    o cube_info: A pointer to the Cube structure.
1231 %
1232 %    o node_info: the address of a structure of type NodeInfo which points to a
1233 %      node in the color cube tree that is to be pruned.
1234 %
1235 */
1236 static size_t DefineImageColormap(Image *image,CubeInfo *cube_info,
1237   NodeInfo *node_info)
1238 {
1239   register ssize_t
1240     i;
1241
1242   size_t
1243     number_children;
1244
1245   /*
1246     Traverse any children.
1247   */
1248   number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
1249   for (i=0; i < (ssize_t) number_children; i++)
1250     if (node_info->child[i] != (NodeInfo *) NULL)
1251       (void) DefineImageColormap(image,cube_info,node_info->child[i]);
1252   if (node_info->number_unique != 0)
1253     {
1254       register double
1255         alpha;
1256
1257       register PixelInfo
1258         *magick_restrict q;
1259
1260       /*
1261         Colormap entry is defined by the mean color in this cube.
1262       */
1263       q=image->colormap+image->colors;
1264       alpha=(double) ((MagickOffsetType) node_info->number_unique);
1265       alpha=PerceptibleReciprocal(alpha);
1266       if (cube_info->associate_alpha == MagickFalse)
1267         {
1268           q->red=(double) ClampToQuantum(alpha*QuantumRange*
1269             node_info->total_color.red);
1270           q->green=(double) ClampToQuantum(alpha*QuantumRange*
1271             node_info->total_color.green);
1272           q->blue=(double) ClampToQuantum(alpha*QuantumRange*
1273             node_info->total_color.blue);
1274           q->alpha=(double) OpaqueAlpha;
1275         }
1276       else
1277         {
1278           double
1279             opacity;
1280
1281           opacity=(double) (alpha*QuantumRange*node_info->total_color.alpha);
1282           q->alpha=(double) ClampToQuantum(opacity);
1283           if (q->alpha == OpaqueAlpha)
1284             {
1285               q->red=(double) ClampToQuantum(alpha*QuantumRange*
1286                 node_info->total_color.red);
1287               q->green=(double) ClampToQuantum(alpha*QuantumRange*
1288                 node_info->total_color.green);
1289               q->blue=(double) ClampToQuantum(alpha*QuantumRange*
1290                 node_info->total_color.blue);
1291             }
1292           else
1293             {
1294               double
1295                 gamma;
1296
1297               gamma=(double) (QuantumScale*q->alpha);
1298               gamma=PerceptibleReciprocal(gamma);
1299               q->red=(double) ClampToQuantum(alpha*gamma*QuantumRange*
1300                 node_info->total_color.red);
1301               q->green=(double) ClampToQuantum(alpha*gamma*QuantumRange*
1302                 node_info->total_color.green);
1303               q->blue=(double) ClampToQuantum(alpha*gamma*QuantumRange*
1304                 node_info->total_color.blue);
1305               if (node_info->number_unique > cube_info->transparent_pixels)
1306                 {
1307                   cube_info->transparent_pixels=node_info->number_unique;
1308                   cube_info->transparent_index=(ssize_t) image->colors;
1309                 }
1310             }
1311         }
1312       node_info->color_number=image->colors++;
1313     }
1314   return(image->colors);
1315 }
1316 \f
1317 /*
1318 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1319 %                                                                             %
1320 %                                                                             %
1321 %                                                                             %
1322 +   D e s t r o y C u b e I n f o                                             %
1323 %                                                                             %
1324 %                                                                             %
1325 %                                                                             %
1326 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1327 %
1328 %  DestroyCubeInfo() deallocates memory associated with an image.
1329 %
1330 %  The format of the DestroyCubeInfo method is:
1331 %
1332 %      DestroyCubeInfo(CubeInfo *cube_info)
1333 %
1334 %  A description of each parameter follows:
1335 %
1336 %    o cube_info: the address of a structure of type CubeInfo.
1337 %
1338 */
1339 static void DestroyCubeInfo(CubeInfo *cube_info)
1340 {
1341   register Nodes
1342     *nodes;
1343
1344   /*
1345     Release color cube tree storage.
1346   */
1347   do
1348   {
1349     nodes=cube_info->node_queue->next;
1350     cube_info->node_queue->nodes=(NodeInfo *) RelinquishMagickMemory(
1351       cube_info->node_queue->nodes);
1352     cube_info->node_queue=(Nodes *) RelinquishMagickMemory(
1353       cube_info->node_queue);
1354     cube_info->node_queue=nodes;
1355   } while (cube_info->node_queue != (Nodes *) NULL);
1356   if (cube_info->memory_info != (MemoryInfo *) NULL)
1357     cube_info->memory_info=RelinquishVirtualMemory(cube_info->memory_info);
1358   cube_info->quantize_info=DestroyQuantizeInfo(cube_info->quantize_info);
1359   cube_info=(CubeInfo *) RelinquishMagickMemory(cube_info);
1360 }
1361 \f
1362 /*
1363 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1364 %                                                                             %
1365 %                                                                             %
1366 %                                                                             %
1367 %   D e s t r o y Q u a n t i z e I n f o                                     %
1368 %                                                                             %
1369 %                                                                             %
1370 %                                                                             %
1371 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1372 %
1373 %  DestroyQuantizeInfo() deallocates memory associated with an QuantizeInfo
1374 %  structure.
1375 %
1376 %  The format of the DestroyQuantizeInfo method is:
1377 %
1378 %      QuantizeInfo *DestroyQuantizeInfo(QuantizeInfo *quantize_info)
1379 %
1380 %  A description of each parameter follows:
1381 %
1382 %    o quantize_info: Specifies a pointer to an QuantizeInfo structure.
1383 %
1384 */
1385 MagickExport QuantizeInfo *DestroyQuantizeInfo(QuantizeInfo *quantize_info)
1386 {
1387   (void) LogMagickEvent(TraceEvent,GetMagickModule(),"...");
1388   assert(quantize_info != (QuantizeInfo *) NULL);
1389   assert(quantize_info->signature == MagickCoreSignature);
1390   quantize_info->signature=(~MagickCoreSignature);
1391   quantize_info=(QuantizeInfo *) RelinquishMagickMemory(quantize_info);
1392   return(quantize_info);
1393 }
1394 \f
1395 /*
1396 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1397 %                                                                             %
1398 %                                                                             %
1399 %                                                                             %
1400 +   D i t h e r I m a g e                                                     %
1401 %                                                                             %
1402 %                                                                             %
1403 %                                                                             %
1404 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1405 %
1406 %  DitherImage() distributes the difference between an original image and
1407 %  the corresponding color reduced algorithm to neighboring pixels using
1408 %  serpentine-scan Floyd-Steinberg error diffusion. DitherImage returns
1409 %  MagickTrue if the image is dithered otherwise MagickFalse.
1410 %
1411 %  The format of the DitherImage method is:
1412 %
1413 %      MagickBooleanType DitherImage(Image *image,CubeInfo *cube_info,
1414 %        ExceptionInfo *exception)
1415 %
1416 %  A description of each parameter follows.
1417 %
1418 %    o image: the image.
1419 %
1420 %    o cube_info: A pointer to the Cube structure.
1421 %
1422 %    o exception: return any errors or warnings in this structure.
1423 %
1424 */
1425
1426 static DoublePixelPacket **DestroyPixelThreadSet(DoublePixelPacket **pixels)
1427 {
1428   register ssize_t
1429     i;
1430
1431   assert(pixels != (DoublePixelPacket **) NULL);
1432   for (i=0; i < (ssize_t) GetMagickResourceLimit(ThreadResource); i++)
1433     if (pixels[i] != (DoublePixelPacket *) NULL)
1434       pixels[i]=(DoublePixelPacket *) RelinquishMagickMemory(pixels[i]);
1435   pixels=(DoublePixelPacket **) RelinquishMagickMemory(pixels);
1436   return(pixels);
1437 }
1438
1439 static DoublePixelPacket **AcquirePixelThreadSet(const size_t count)
1440 {
1441   DoublePixelPacket
1442     **pixels;
1443
1444   register ssize_t
1445     i;
1446
1447   size_t
1448     number_threads;
1449
1450   number_threads=(size_t) GetMagickResourceLimit(ThreadResource);
1451   pixels=(DoublePixelPacket **) AcquireQuantumMemory(number_threads,
1452     sizeof(*pixels));
1453   if (pixels == (DoublePixelPacket **) NULL)
1454     return((DoublePixelPacket **) NULL);
1455   (void) ResetMagickMemory(pixels,0,number_threads*sizeof(*pixels));
1456   for (i=0; i < (ssize_t) number_threads; i++)
1457   {
1458     pixels[i]=(DoublePixelPacket *) AcquireQuantumMemory(count,2*
1459       sizeof(**pixels));
1460     if (pixels[i] == (DoublePixelPacket *) NULL)
1461       return(DestroyPixelThreadSet(pixels));
1462   }
1463   return(pixels);
1464 }
1465
1466 static inline ssize_t CacheOffset(CubeInfo *cube_info,
1467   const DoublePixelPacket *pixel)
1468 {
1469 #define RedShift(pixel) (((pixel) >> CacheShift) << (0*(8-CacheShift)))
1470 #define GreenShift(pixel) (((pixel) >> CacheShift) << (1*(8-CacheShift)))
1471 #define BlueShift(pixel) (((pixel) >> CacheShift) << (2*(8-CacheShift)))
1472 #define AlphaShift(pixel) (((pixel) >> CacheShift) << (3*(8-CacheShift)))
1473
1474   ssize_t
1475     offset;
1476
1477   offset=(ssize_t) (RedShift(ScaleQuantumToChar(ClampPixel(pixel->red))) |
1478     GreenShift(ScaleQuantumToChar(ClampPixel(pixel->green))) |
1479     BlueShift(ScaleQuantumToChar(ClampPixel(pixel->blue))));
1480   if (cube_info->associate_alpha != MagickFalse)
1481     offset|=AlphaShift(ScaleQuantumToChar(ClampPixel(pixel->alpha)));
1482   return(offset);
1483 }
1484
1485 static MagickBooleanType FloydSteinbergDither(Image *image,CubeInfo *cube_info,
1486   ExceptionInfo *exception)
1487 {
1488 #define DitherImageTag  "Dither/Image"
1489
1490   CacheView
1491     *image_view;
1492
1493   DoublePixelPacket
1494     **pixels;
1495
1496   MagickBooleanType
1497     status;
1498
1499   ssize_t
1500     y;
1501
1502   /*
1503     Distribute quantization error using Floyd-Steinberg.
1504   */
1505   pixels=AcquirePixelThreadSet(image->columns);
1506   if (pixels == (DoublePixelPacket **) NULL)
1507     return(MagickFalse);
1508   status=MagickTrue;
1509   image_view=AcquireAuthenticCacheView(image,exception);
1510   for (y=0; y < (ssize_t) image->rows; y++)
1511   {
1512     const int
1513       id = GetOpenMPThreadId();
1514
1515     CubeInfo
1516       cube;
1517
1518     DoublePixelPacket
1519       *current,
1520       *previous;
1521
1522     register Quantum
1523       *magick_restrict q;
1524
1525     register ssize_t
1526       x;
1527
1528     size_t
1529       index;
1530
1531     ssize_t
1532       v;
1533
1534     if (status == MagickFalse)
1535       continue;
1536     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
1537     if (q == (Quantum *) NULL)
1538       {
1539         status=MagickFalse;
1540         continue;
1541       }
1542     cube=(*cube_info);
1543     current=pixels[id]+(y & 0x01)*image->columns;
1544     previous=pixels[id]+((y+1) & 0x01)*image->columns;
1545     v=(ssize_t) ((y & 0x01) != 0 ? -1 : 1);
1546     for (x=0; x < (ssize_t) image->columns; x++)
1547     {
1548       DoublePixelPacket
1549         color,
1550         pixel;
1551
1552       register ssize_t
1553         i;
1554
1555       ssize_t
1556         u;
1557
1558       u=(y & 0x01) != 0 ? (ssize_t) image->columns-1-x : x;
1559       AssociateAlphaPixel(image,&cube,q+u*GetPixelChannels(image),&pixel);
1560       if (x > 0)
1561         {
1562           pixel.red+=7*current[u-v].red/16;
1563           pixel.green+=7*current[u-v].green/16;
1564           pixel.blue+=7*current[u-v].blue/16;
1565           if (cube.associate_alpha != MagickFalse)
1566             pixel.alpha+=7*current[u-v].alpha/16;
1567         }
1568       if (y > 0)
1569         {
1570           if (x < (ssize_t) (image->columns-1))
1571             {
1572               pixel.red+=previous[u+v].red/16;
1573               pixel.green+=previous[u+v].green/16;
1574               pixel.blue+=previous[u+v].blue/16;
1575               if (cube.associate_alpha != MagickFalse)
1576                 pixel.alpha+=previous[u+v].alpha/16;
1577             }
1578           pixel.red+=5*previous[u].red/16;
1579           pixel.green+=5*previous[u].green/16;
1580           pixel.blue+=5*previous[u].blue/16;
1581           if (cube.associate_alpha != MagickFalse)
1582             pixel.alpha+=5*previous[u].alpha/16;
1583           if (x > 0)
1584             {
1585               pixel.red+=3*previous[u-v].red/16;
1586               pixel.green+=3*previous[u-v].green/16;
1587               pixel.blue+=3*previous[u-v].blue/16;
1588               if (cube.associate_alpha != MagickFalse)
1589                 pixel.alpha+=3*previous[u-v].alpha/16;
1590             }
1591         }
1592       pixel.red=(double) ClampPixel(pixel.red);
1593       pixel.green=(double) ClampPixel(pixel.green);
1594       pixel.blue=(double) ClampPixel(pixel.blue);
1595       if (cube.associate_alpha != MagickFalse)
1596         pixel.alpha=(double) ClampPixel(pixel.alpha);
1597       i=CacheOffset(&cube,&pixel);
1598       if (cube.cache[i] < 0)
1599         {
1600           register NodeInfo
1601             *node_info;
1602
1603           register size_t
1604             node_id;
1605
1606           /*
1607             Identify the deepest node containing the pixel's color.
1608           */
1609           node_info=cube.root;
1610           for (index=MaxTreeDepth-1; (ssize_t) index > 0; index--)
1611           {
1612             node_id=ColorToNodeId(&cube,&pixel,index);
1613             if (node_info->child[node_id] == (NodeInfo *) NULL)
1614               break;
1615             node_info=node_info->child[node_id];
1616           }
1617           /*
1618             Find closest color among siblings and their children.
1619           */
1620           cube.target=pixel;
1621           cube.distance=(double) (4.0*(QuantumRange+1.0)*(QuantumRange+1.0)+
1622             1.0);
1623           ClosestColor(image,&cube,node_info->parent);
1624           cube.cache[i]=(ssize_t) cube.color_number;
1625         }
1626       /*
1627         Assign pixel to closest colormap entry.
1628       */
1629       index=(size_t) cube.cache[i];
1630       if (image->storage_class == PseudoClass)
1631         SetPixelIndex(image,(Quantum) index,q+u*GetPixelChannels(image));
1632       if (cube.quantize_info->measure_error == MagickFalse)
1633         {
1634           SetPixelRed(image,ClampToQuantum(image->colormap[index].red),
1635             q+u*GetPixelChannels(image));
1636           SetPixelGreen(image,ClampToQuantum(image->colormap[index].green),
1637             q+u*GetPixelChannels(image));
1638           SetPixelBlue(image,ClampToQuantum(image->colormap[index].blue),
1639             q+u*GetPixelChannels(image));
1640           if (cube.associate_alpha != MagickFalse)
1641             SetPixelAlpha(image,ClampToQuantum(image->colormap[index].alpha),
1642               q+u*GetPixelChannels(image));
1643         }
1644       if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1645         status=MagickFalse;
1646       /*
1647         Store the error.
1648       */
1649       AssociateAlphaPixelInfo(&cube,image->colormap+index,&color);
1650       current[u].red=pixel.red-color.red;
1651       current[u].green=pixel.green-color.green;
1652       current[u].blue=pixel.blue-color.blue;
1653       if (cube.associate_alpha != MagickFalse)
1654         current[u].alpha=pixel.alpha-color.alpha;
1655       if (image->progress_monitor != (MagickProgressMonitor) NULL)
1656         {
1657           MagickBooleanType
1658             proceed;
1659
1660           proceed=SetImageProgress(image,DitherImageTag,(MagickOffsetType) y,
1661             image->rows);
1662           if (proceed == MagickFalse)
1663             status=MagickFalse;
1664         }
1665     }
1666   }
1667   image_view=DestroyCacheView(image_view);
1668   pixels=DestroyPixelThreadSet(pixels);
1669   return(MagickTrue);
1670 }
1671
1672 static MagickBooleanType
1673   RiemersmaDither(Image *,CacheView *,CubeInfo *,const unsigned int,
1674     ExceptionInfo *);
1675
1676 static void Riemersma(Image *image,CacheView *image_view,CubeInfo *cube_info,
1677   const size_t level,const unsigned int direction,ExceptionInfo *exception)
1678 {
1679   if (level == 1)
1680     switch (direction)
1681     {
1682       case WestGravity:
1683       {
1684         (void) RiemersmaDither(image,image_view,cube_info,EastGravity,
1685           exception);
1686         (void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
1687           exception);
1688         (void) RiemersmaDither(image,image_view,cube_info,WestGravity,
1689           exception);
1690         break;
1691       }
1692       case EastGravity:
1693       {
1694         (void) RiemersmaDither(image,image_view,cube_info,WestGravity,
1695           exception);
1696         (void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
1697           exception);
1698         (void) RiemersmaDither(image,image_view,cube_info,EastGravity,
1699           exception);
1700         break;
1701       }
1702       case NorthGravity:
1703       {
1704         (void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
1705           exception);
1706         (void) RiemersmaDither(image,image_view,cube_info,EastGravity,
1707           exception);
1708         (void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
1709           exception);
1710         break;
1711       }
1712       case SouthGravity:
1713       {
1714         (void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
1715           exception);
1716         (void) RiemersmaDither(image,image_view,cube_info,WestGravity,
1717           exception);
1718         (void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
1719           exception);
1720         break;
1721       }
1722       default:
1723         break;
1724     }
1725   else
1726     switch (direction)
1727     {
1728       case WestGravity:
1729       {
1730         Riemersma(image,image_view,cube_info,level-1,NorthGravity,
1731           exception);
1732         (void) RiemersmaDither(image,image_view,cube_info,EastGravity,
1733           exception);
1734         Riemersma(image,image_view,cube_info,level-1,WestGravity,
1735           exception);
1736         (void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
1737           exception);
1738         Riemersma(image,image_view,cube_info,level-1,WestGravity,
1739           exception);
1740         (void) RiemersmaDither(image,image_view,cube_info,WestGravity,
1741           exception);
1742         Riemersma(image,image_view,cube_info,level-1,SouthGravity,
1743           exception);
1744         break;
1745       }
1746       case EastGravity:
1747       {
1748         Riemersma(image,image_view,cube_info,level-1,SouthGravity,
1749           exception);
1750         (void) RiemersmaDither(image,image_view,cube_info,WestGravity,
1751           exception);
1752         Riemersma(image,image_view,cube_info,level-1,EastGravity,
1753           exception);
1754         (void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
1755           exception);
1756         Riemersma(image,image_view,cube_info,level-1,EastGravity,
1757           exception);
1758         (void) RiemersmaDither(image,image_view,cube_info,EastGravity,
1759           exception);
1760         Riemersma(image,image_view,cube_info,level-1,NorthGravity,
1761           exception);
1762         break;
1763       }
1764       case NorthGravity:
1765       {
1766         Riemersma(image,image_view,cube_info,level-1,WestGravity,
1767           exception);
1768         (void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
1769           exception);
1770         Riemersma(image,image_view,cube_info,level-1,NorthGravity,
1771           exception);
1772         (void) RiemersmaDither(image,image_view,cube_info,EastGravity,
1773           exception);
1774         Riemersma(image,image_view,cube_info,level-1,NorthGravity,
1775           exception);
1776         (void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
1777           exception);
1778         Riemersma(image,image_view,cube_info,level-1,EastGravity,
1779           exception);
1780         break;
1781       }
1782       case SouthGravity:
1783       {
1784         Riemersma(image,image_view,cube_info,level-1,EastGravity,
1785           exception);
1786         (void) RiemersmaDither(image,image_view,cube_info,NorthGravity,
1787           exception);
1788         Riemersma(image,image_view,cube_info,level-1,SouthGravity,
1789           exception);
1790         (void) RiemersmaDither(image,image_view,cube_info,WestGravity,
1791           exception);
1792         Riemersma(image,image_view,cube_info,level-1,SouthGravity,
1793           exception);
1794         (void) RiemersmaDither(image,image_view,cube_info,SouthGravity,
1795           exception);
1796         Riemersma(image,image_view,cube_info,level-1,WestGravity,
1797           exception);
1798         break;
1799       }
1800       default:
1801         break;
1802     }
1803 }
1804
1805 static MagickBooleanType RiemersmaDither(Image *image,CacheView *image_view,
1806   CubeInfo *cube_info,const unsigned int direction,ExceptionInfo *exception)
1807 {
1808 #define DitherImageTag  "Dither/Image"
1809
1810   DoublePixelPacket
1811     color,
1812     pixel;
1813
1814   MagickBooleanType
1815     proceed;
1816
1817   register CubeInfo
1818     *p;
1819
1820   size_t
1821     index;
1822
1823   p=cube_info;
1824   if ((p->x >= 0) && (p->x < (ssize_t) image->columns) &&
1825       (p->y >= 0) && (p->y < (ssize_t) image->rows))
1826     {
1827       register Quantum
1828         *magick_restrict q;
1829
1830       register ssize_t
1831         i;
1832
1833       /*
1834         Distribute error.
1835       */
1836       q=GetCacheViewAuthenticPixels(image_view,p->x,p->y,1,1,exception);
1837       if (q == (Quantum *) NULL)
1838         return(MagickFalse);
1839       AssociateAlphaPixel(image,cube_info,q,&pixel);
1840       for (i=0; i < ErrorQueueLength; i++)
1841       {
1842         pixel.red+=p->weights[i]*p->error[i].red;
1843         pixel.green+=p->weights[i]*p->error[i].green;
1844         pixel.blue+=p->weights[i]*p->error[i].blue;
1845         if (cube_info->associate_alpha != MagickFalse)
1846           pixel.alpha+=p->weights[i]*p->error[i].alpha;
1847       }
1848       pixel.red=(double) ClampPixel(pixel.red);
1849       pixel.green=(double) ClampPixel(pixel.green);
1850       pixel.blue=(double) ClampPixel(pixel.blue);
1851       if (cube_info->associate_alpha != MagickFalse)
1852         pixel.alpha=(double) ClampPixel(pixel.alpha);
1853       i=CacheOffset(cube_info,&pixel);
1854       if (p->cache[i] < 0)
1855         {
1856           register NodeInfo
1857             *node_info;
1858
1859           register size_t
1860             id;
1861
1862           /*
1863             Identify the deepest node containing the pixel's color.
1864           */
1865           node_info=p->root;
1866           for (index=MaxTreeDepth-1; (ssize_t) index > 0; index--)
1867           {
1868             id=ColorToNodeId(cube_info,&pixel,index);
1869             if (node_info->child[id] == (NodeInfo *) NULL)
1870               break;
1871             node_info=node_info->child[id];
1872           }
1873           /*
1874             Find closest color among siblings and their children.
1875           */
1876           p->target=pixel;
1877           p->distance=(double) (4.0*(QuantumRange+1.0)*((double)
1878             QuantumRange+1.0)+1.0);
1879           ClosestColor(image,p,node_info->parent);
1880           p->cache[i]=(ssize_t) p->color_number;
1881         }
1882       /*
1883         Assign pixel to closest colormap entry.
1884       */
1885       index=(size_t) p->cache[i];
1886       if (image->storage_class == PseudoClass)
1887         SetPixelIndex(image,(Quantum) index,q);
1888       if (cube_info->quantize_info->measure_error == MagickFalse)
1889         {
1890           SetPixelRed(image,ClampToQuantum(image->colormap[index].red),q);
1891           SetPixelGreen(image,ClampToQuantum(image->colormap[index].green),q);
1892           SetPixelBlue(image,ClampToQuantum(image->colormap[index].blue),q);
1893           if (cube_info->associate_alpha != MagickFalse)
1894             SetPixelAlpha(image,ClampToQuantum(image->colormap[index].alpha),q);
1895         }
1896       if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1897         return(MagickFalse);
1898       /*
1899         Propagate the error as the last entry of the error queue.
1900       */
1901       (void) CopyMagickMemory(p->error,p->error+1,(ErrorQueueLength-1)*
1902         sizeof(p->error[0]));
1903       AssociateAlphaPixelInfo(cube_info,image->colormap+index,&color);
1904       p->error[ErrorQueueLength-1].red=pixel.red-color.red;
1905       p->error[ErrorQueueLength-1].green=pixel.green-color.green;
1906       p->error[ErrorQueueLength-1].blue=pixel.blue-color.blue;
1907       if (cube_info->associate_alpha != MagickFalse)
1908         p->error[ErrorQueueLength-1].alpha=pixel.alpha-color.alpha;
1909       proceed=SetImageProgress(image,DitherImageTag,p->offset,p->span);
1910       if (proceed == MagickFalse)
1911         return(MagickFalse);
1912       p->offset++;
1913     }
1914   switch (direction)
1915   {
1916     case WestGravity: p->x--; break;
1917     case EastGravity: p->x++; break;
1918     case NorthGravity: p->y--; break;
1919     case SouthGravity: p->y++; break;
1920   }
1921   return(MagickTrue);
1922 }
1923
1924 static MagickBooleanType DitherImage(Image *image,CubeInfo *cube_info,
1925   ExceptionInfo *exception)
1926 {
1927   CacheView
1928     *image_view;
1929
1930   MagickBooleanType
1931     status;
1932
1933   register ssize_t
1934     i;
1935
1936   size_t
1937     depth;
1938
1939   if (cube_info->quantize_info->dither_method != RiemersmaDitherMethod)
1940     return(FloydSteinbergDither(image,cube_info,exception));
1941   /*
1942     Distribute quantization error along a Hilbert curve.
1943   */
1944   (void) ResetMagickMemory(cube_info->error,0,ErrorQueueLength*
1945     sizeof(*cube_info->error));
1946   cube_info->x=0;
1947   cube_info->y=0;
1948   i=MagickMax((ssize_t) image->columns,(ssize_t) image->rows);
1949   for (depth=1; i != 0; depth++)
1950     i>>=1;
1951   if ((ssize_t) (1L << depth) < MagickMax((ssize_t) image->columns,(ssize_t) image->rows))
1952     depth++;
1953   cube_info->offset=0;
1954   cube_info->span=(MagickSizeType) image->columns*image->rows;
1955   image_view=AcquireAuthenticCacheView(image,exception);
1956   if (depth > 1)
1957     Riemersma(image,image_view,cube_info,depth-1,NorthGravity,exception);
1958   status=RiemersmaDither(image,image_view,cube_info,ForgetGravity,exception);
1959   image_view=DestroyCacheView(image_view);
1960   return(status);
1961 }
1962 \f
1963 /*
1964 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1965 %                                                                             %
1966 %                                                                             %
1967 %                                                                             %
1968 +   G e t C u b e I n f o                                                     %
1969 %                                                                             %
1970 %                                                                             %
1971 %                                                                             %
1972 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1973 %
1974 %  GetCubeInfo() initialize the Cube data structure.
1975 %
1976 %  The format of the GetCubeInfo method is:
1977 %
1978 %      CubeInfo GetCubeInfo(const QuantizeInfo *quantize_info,
1979 %        const size_t depth,const size_t maximum_colors)
1980 %
1981 %  A description of each parameter follows.
1982 %
1983 %    o quantize_info: Specifies a pointer to an QuantizeInfo structure.
1984 %
1985 %    o depth: Normally, this integer value is zero or one.  A zero or
1986 %      one tells Quantize to choose a optimal tree depth of Log4(number_colors).
1987 %      A tree of this depth generally allows the best representation of the
1988 %      reference image with the least amount of memory and the fastest
1989 %      computational speed.  In some cases, such as an image with low color
1990 %      dispersion (a few number of colors), a value other than
1991 %      Log4(number_colors) is required.  To expand the color tree completely,
1992 %      use a value of 8.
1993 %
1994 %    o maximum_colors: maximum colors.
1995 %
1996 */
1997 static CubeInfo *GetCubeInfo(const QuantizeInfo *quantize_info,
1998   const size_t depth,const size_t maximum_colors)
1999 {
2000   CubeInfo
2001     *cube_info;
2002
2003   double
2004     sum,
2005     weight;
2006
2007   register ssize_t
2008     i;
2009
2010   size_t
2011     length;
2012
2013   /*
2014     Initialize tree to describe color cube_info.
2015   */
2016   cube_info=(CubeInfo *) AcquireMagickMemory(sizeof(*cube_info));
2017   if (cube_info == (CubeInfo *) NULL)
2018     return((CubeInfo *) NULL);
2019   (void) ResetMagickMemory(cube_info,0,sizeof(*cube_info));
2020   cube_info->depth=depth;
2021   if (cube_info->depth > MaxTreeDepth)
2022     cube_info->depth=MaxTreeDepth;
2023   if (cube_info->depth < 2)
2024     cube_info->depth=2;
2025   cube_info->maximum_colors=maximum_colors;
2026   /*
2027     Initialize root node.
2028   */
2029   cube_info->root=GetNodeInfo(cube_info,0,0,(NodeInfo *) NULL);
2030   if (cube_info->root == (NodeInfo *) NULL)
2031     return((CubeInfo *) NULL);
2032   cube_info->root->parent=cube_info->root;
2033   cube_info->quantize_info=CloneQuantizeInfo(quantize_info);
2034   if (cube_info->quantize_info->dither_method == NoDitherMethod)
2035     return(cube_info);
2036   /*
2037     Initialize dither resources.
2038   */
2039   length=(size_t) (1UL << (4*(8-CacheShift)));
2040   cube_info->memory_info=AcquireVirtualMemory(length,sizeof(*cube_info->cache));
2041   if (cube_info->memory_info == (MemoryInfo *) NULL)
2042     return((CubeInfo *) NULL);
2043   cube_info->cache=(ssize_t *) GetVirtualMemoryBlob(cube_info->memory_info);
2044   /*
2045     Initialize color cache.
2046   */
2047   (void) ResetMagickMemory(cube_info->cache,(-1),sizeof(*cube_info->cache)*
2048     length);
2049   /*
2050     Distribute weights along a curve of exponential decay.
2051   */
2052   weight=1.0;
2053   for (i=0; i < ErrorQueueLength; i++)
2054   {
2055     cube_info->weights[ErrorQueueLength-i-1]=PerceptibleReciprocal(weight);
2056     weight*=exp(log(((double) QuantumRange+1.0))/(ErrorQueueLength-1.0));
2057   }
2058   /*
2059     Normalize the weighting factors.
2060   */
2061   weight=0.0;
2062   for (i=0; i < ErrorQueueLength; i++)
2063     weight+=cube_info->weights[i];
2064   sum=0.0;
2065   for (i=0; i < ErrorQueueLength; i++)
2066   {
2067     cube_info->weights[i]/=weight;
2068     sum+=cube_info->weights[i];
2069   }
2070   cube_info->weights[0]+=1.0-sum;
2071   return(cube_info);
2072 }
2073 \f
2074 /*
2075 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2076 %                                                                             %
2077 %                                                                             %
2078 %                                                                             %
2079 +   G e t N o d e I n f o                                                     %
2080 %                                                                             %
2081 %                                                                             %
2082 %                                                                             %
2083 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2084 %
2085 %  GetNodeInfo() allocates memory for a new node in the color cube tree and
2086 %  presets all fields to zero.
2087 %
2088 %  The format of the GetNodeInfo method is:
2089 %
2090 %      NodeInfo *GetNodeInfo(CubeInfo *cube_info,const size_t id,
2091 %        const size_t level,NodeInfo *parent)
2092 %
2093 %  A description of each parameter follows.
2094 %
2095 %    o node: The GetNodeInfo method returns a pointer to a queue of nodes.
2096 %
2097 %    o id: Specifies the child number of the node.
2098 %
2099 %    o level: Specifies the level in the storage_class the node resides.
2100 %
2101 */
2102 static NodeInfo *GetNodeInfo(CubeInfo *cube_info,const size_t id,
2103   const size_t level,NodeInfo *parent)
2104 {
2105   NodeInfo
2106     *node_info;
2107
2108   if (cube_info->free_nodes == 0)
2109     {
2110       Nodes
2111         *nodes;
2112
2113       /*
2114         Allocate a new queue of nodes.
2115       */
2116       nodes=(Nodes *) AcquireMagickMemory(sizeof(*nodes));
2117       if (nodes == (Nodes *) NULL)
2118         return((NodeInfo *) NULL);
2119       nodes->nodes=(NodeInfo *) AcquireQuantumMemory(NodesInAList,
2120         sizeof(*nodes->nodes));
2121       if (nodes->nodes == (NodeInfo *) NULL)
2122         return((NodeInfo *) NULL);
2123       nodes->next=cube_info->node_queue;
2124       cube_info->node_queue=nodes;
2125       cube_info->next_node=nodes->nodes;
2126       cube_info->free_nodes=NodesInAList;
2127     }
2128   cube_info->nodes++;
2129   cube_info->free_nodes--;
2130   node_info=cube_info->next_node++;
2131   (void) ResetMagickMemory(node_info,0,sizeof(*node_info));
2132   node_info->parent=parent;
2133   node_info->id=id;
2134   node_info->level=level;
2135   return(node_info);
2136 }
2137 \f
2138 /*
2139 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2140 %                                                                             %
2141 %                                                                             %
2142 %                                                                             %
2143 %  G e t I m a g e Q u a n t i z e E r r o r                                  %
2144 %                                                                             %
2145 %                                                                             %
2146 %                                                                             %
2147 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2148 %
2149 %  GetImageQuantizeError() measures the difference between the original
2150 %  and quantized images.  This difference is the total quantization error.
2151 %  The error is computed by summing over all pixels in an image the distance
2152 %  squared in RGB space between each reference pixel value and its quantized
2153 %  value.  These values are computed:
2154 %
2155 %    o mean_error_per_pixel:  This value is the mean error for any single
2156 %      pixel in the image.
2157 %
2158 %    o normalized_mean_square_error:  This value is the normalized mean
2159 %      quantization error for any single pixel in the image.  This distance
2160 %      measure is normalized to a range between 0 and 1.  It is independent
2161 %      of the range of red, green, and blue values in the image.
2162 %
2163 %    o normalized_maximum_square_error:  Thsi value is the normalized
2164 %      maximum quantization error for any single pixel in the image.  This
2165 %      distance measure is normalized to a range between 0 and 1.  It is
2166 %      independent of the range of red, green, and blue values in your image.
2167 %
2168 %  The format of the GetImageQuantizeError method is:
2169 %
2170 %      MagickBooleanType GetImageQuantizeError(Image *image,
2171 %        ExceptionInfo *exception)
2172 %
2173 %  A description of each parameter follows.
2174 %
2175 %    o image: the image.
2176 %
2177 %    o exception: return any errors or warnings in this structure.
2178 %
2179 */
2180 MagickExport MagickBooleanType GetImageQuantizeError(Image *image,
2181   ExceptionInfo *exception)
2182 {
2183   CacheView
2184     *image_view;
2185
2186   double
2187     alpha,
2188     area,
2189     beta,
2190     distance,
2191     maximum_error,
2192     mean_error,
2193     mean_error_per_pixel;
2194
2195   size_t
2196     index;
2197
2198   ssize_t
2199     y;
2200
2201   assert(image != (Image *) NULL);
2202   assert(image->signature == MagickCoreSignature);
2203   if (image->debug != MagickFalse)
2204     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
2205   image->total_colors=GetNumberColors(image,(FILE *) NULL,exception);
2206   (void) ResetMagickMemory(&image->error,0,sizeof(image->error));
2207   if (image->storage_class == DirectClass)
2208     return(MagickTrue);
2209   alpha=1.0;
2210   beta=1.0;
2211   area=3.0*image->columns*image->rows;
2212   maximum_error=0.0;
2213   mean_error_per_pixel=0.0;
2214   mean_error=0.0;
2215   image_view=AcquireVirtualCacheView(image,exception);
2216   for (y=0; y < (ssize_t) image->rows; y++)
2217   {
2218     register const Quantum
2219       *magick_restrict p;
2220
2221     register ssize_t
2222       x;
2223
2224     p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
2225     if (p == (const Quantum *) NULL)
2226       break;
2227     for (x=0; x < (ssize_t) image->columns; x++)
2228     {
2229       index=GetPixelIndex(image,p);
2230       if (image->alpha_trait == BlendPixelTrait)
2231         {
2232           alpha=(double) (QuantumScale*GetPixelAlpha(image,p));
2233           beta=(double) (QuantumScale*image->colormap[index].alpha);
2234         }
2235       distance=fabs((double) (alpha*GetPixelRed(image,p)-beta*
2236         image->colormap[index].red));
2237       mean_error_per_pixel+=distance;
2238       mean_error+=distance*distance;
2239       if (distance > maximum_error)
2240         maximum_error=distance;
2241       distance=fabs((double) (alpha*GetPixelGreen(image,p)-beta*
2242         image->colormap[index].green));
2243       mean_error_per_pixel+=distance;
2244       mean_error+=distance*distance;
2245       if (distance > maximum_error)
2246         maximum_error=distance;
2247       distance=fabs((double) (alpha*GetPixelBlue(image,p)-beta*
2248         image->colormap[index].blue));
2249       mean_error_per_pixel+=distance;
2250       mean_error+=distance*distance;
2251       if (distance > maximum_error)
2252         maximum_error=distance;
2253       p+=GetPixelChannels(image);
2254     }
2255   }
2256   image_view=DestroyCacheView(image_view);
2257   image->error.mean_error_per_pixel=(double) mean_error_per_pixel/area;
2258   image->error.normalized_mean_error=(double) QuantumScale*QuantumScale*
2259     mean_error/area;
2260   image->error.normalized_maximum_error=(double) QuantumScale*maximum_error;
2261   return(MagickTrue);
2262 }
2263 \f
2264 /*
2265 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2266 %                                                                             %
2267 %                                                                             %
2268 %                                                                             %
2269 %   G e t Q u a n t i z e I n f o                                             %
2270 %                                                                             %
2271 %                                                                             %
2272 %                                                                             %
2273 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2274 %
2275 %  GetQuantizeInfo() initializes the QuantizeInfo structure.
2276 %
2277 %  The format of the GetQuantizeInfo method is:
2278 %
2279 %      GetQuantizeInfo(QuantizeInfo *quantize_info)
2280 %
2281 %  A description of each parameter follows:
2282 %
2283 %    o quantize_info: Specifies a pointer to a QuantizeInfo structure.
2284 %
2285 */
2286 MagickExport void GetQuantizeInfo(QuantizeInfo *quantize_info)
2287 {
2288   (void) LogMagickEvent(TraceEvent,GetMagickModule(),"...");
2289   assert(quantize_info != (QuantizeInfo *) NULL);
2290   (void) ResetMagickMemory(quantize_info,0,sizeof(*quantize_info));
2291   quantize_info->number_colors=256;
2292   quantize_info->dither_method=RiemersmaDitherMethod;
2293   quantize_info->colorspace=UndefinedColorspace;
2294   quantize_info->measure_error=MagickFalse;
2295   quantize_info->signature=MagickCoreSignature;
2296 }
2297 \f
2298 /*
2299 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2300 %                                                                             %
2301 %                                                                             %
2302 %                                                                             %
2303 %     P o s t e r i z e I m a g e                                             %
2304 %                                                                             %
2305 %                                                                             %
2306 %                                                                             %
2307 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2308 %
2309 %  PosterizeImage() reduces the image to a limited number of colors for a
2310 %  "poster" effect.
2311 %
2312 %  The format of the PosterizeImage method is:
2313 %
2314 %      MagickBooleanType PosterizeImage(Image *image,const size_t levels,
2315 %        const DitherMethod dither_method,ExceptionInfo *exception)
2316 %
2317 %  A description of each parameter follows:
2318 %
2319 %    o image: Specifies a pointer to an Image structure.
2320 %
2321 %    o levels: Number of color levels allowed in each channel.  Very low values
2322 %      (2, 3, or 4) have the most visible effect.
2323 %
2324 %    o dither_method: choose from UndefinedDitherMethod, NoDitherMethod,
2325 %      RiemersmaDitherMethod, FloydSteinbergDitherMethod.
2326 %
2327 %    o exception: return any errors or warnings in this structure.
2328 %
2329 */
2330
2331 static inline double MagickRound(double x)
2332 {
2333   /*
2334     Round the fraction to nearest integer.
2335   */
2336   if ((x-floor(x)) < (ceil(x)-x))
2337     return(floor(x));
2338   return(ceil(x));
2339 }
2340
2341 MagickExport MagickBooleanType PosterizeImage(Image *image,const size_t levels,
2342   const DitherMethod dither_method,ExceptionInfo *exception)
2343 {
2344 #define PosterizeImageTag  "Posterize/Image"
2345 #define PosterizePixel(pixel) (Quantum) (QuantumRange*(MagickRound( \
2346   QuantumScale*pixel*(levels-1)))/MagickMax((ssize_t) levels-1,1))
2347
2348   CacheView
2349     *image_view;
2350
2351   MagickBooleanType
2352     status;
2353
2354   MagickOffsetType
2355     progress;
2356
2357   QuantizeInfo
2358     *quantize_info;
2359
2360   register ssize_t
2361     i;
2362
2363   ssize_t
2364     y;
2365
2366   assert(image != (Image *) NULL);
2367   assert(image->signature == MagickCoreSignature);
2368   if (image->debug != MagickFalse)
2369     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
2370   assert(exception != (ExceptionInfo *) NULL);
2371   assert(exception->signature == MagickCoreSignature);
2372   if (image->storage_class == PseudoClass)
2373 #if defined(MAGICKCORE_OPENMP_SUPPORT)
2374     #pragma omp parallel for schedule(static,4) shared(progress,status) \
2375       magick_number_threads(image,image,image->colors,1)
2376 #endif
2377     for (i=0; i < (ssize_t) image->colors; i++)
2378     {
2379       /*
2380         Posterize colormap.
2381       */
2382       if ((GetPixelRedTraits(image) & UpdatePixelTrait) != 0)
2383         image->colormap[i].red=(double)
2384           PosterizePixel(image->colormap[i].red);
2385       if ((GetPixelGreenTraits(image) & UpdatePixelTrait) != 0)
2386         image->colormap[i].green=(double)
2387           PosterizePixel(image->colormap[i].green);
2388       if ((GetPixelBlueTraits(image) & UpdatePixelTrait) != 0)
2389         image->colormap[i].blue=(double)
2390           PosterizePixel(image->colormap[i].blue);
2391       if ((GetPixelAlphaTraits(image) & UpdatePixelTrait) != 0)
2392         image->colormap[i].alpha=(double)
2393           PosterizePixel(image->colormap[i].alpha);
2394     }
2395   /*
2396     Posterize image.
2397   */
2398   status=MagickTrue;
2399   progress=0;
2400   image_view=AcquireAuthenticCacheView(image,exception);
2401 #if defined(MAGICKCORE_OPENMP_SUPPORT)
2402   #pragma omp parallel for schedule(static,4) shared(progress,status) \
2403     magick_number_threads(image,image,image->rows,1)
2404 #endif
2405   for (y=0; y < (ssize_t) image->rows; y++)
2406   {
2407     register Quantum
2408       *magick_restrict q;
2409
2410     register ssize_t
2411       x;
2412
2413     if (status == MagickFalse)
2414       continue;
2415     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
2416     if (q == (Quantum *) NULL)
2417       {
2418         status=MagickFalse;
2419         continue;
2420       }
2421     for (x=0; x < (ssize_t) image->columns; x++)
2422     {
2423       if ((GetPixelRedTraits(image) & UpdatePixelTrait) != 0)
2424         SetPixelRed(image,PosterizePixel(GetPixelRed(image,q)),q);
2425       if ((GetPixelGreenTraits(image) & UpdatePixelTrait) != 0)
2426         SetPixelGreen(image,PosterizePixel(GetPixelGreen(image,q)),q);
2427       if ((GetPixelBlueTraits(image) & UpdatePixelTrait) != 0)
2428         SetPixelBlue(image,PosterizePixel(GetPixelBlue(image,q)),q);
2429       if (((GetPixelBlackTraits(image) & UpdatePixelTrait) != 0) &&
2430           (image->colorspace == CMYKColorspace))
2431         SetPixelBlack(image,PosterizePixel(GetPixelBlack(image,q)),q);
2432       if (((GetPixelAlphaTraits(image) & UpdatePixelTrait) != 0) &&
2433           (image->alpha_trait == BlendPixelTrait))
2434         SetPixelAlpha(image,PosterizePixel(GetPixelAlpha(image,q)),q);
2435       q+=GetPixelChannels(image);
2436     }
2437     if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
2438       status=MagickFalse;
2439     if (image->progress_monitor != (MagickProgressMonitor) NULL)
2440       {
2441         MagickBooleanType
2442           proceed;
2443
2444 #if defined(MAGICKCORE_OPENMP_SUPPORT)
2445         #pragma omp critical (MagickCore_PosterizeImage)
2446 #endif
2447         proceed=SetImageProgress(image,PosterizeImageTag,progress++,
2448           image->rows);
2449         if (proceed == MagickFalse)
2450           status=MagickFalse;
2451       }
2452   }
2453   image_view=DestroyCacheView(image_view);
2454   quantize_info=AcquireQuantizeInfo((ImageInfo *) NULL);
2455   quantize_info->number_colors=(size_t) MagickMin((ssize_t) levels*levels*
2456     levels,MaxColormapSize+1);
2457   quantize_info->dither_method=dither_method;
2458   quantize_info->tree_depth=MaxTreeDepth;
2459   status=QuantizeImage(quantize_info,image,exception);
2460   quantize_info=DestroyQuantizeInfo(quantize_info);
2461   return(status);
2462 }
2463 \f
2464 /*
2465 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2466 %                                                                             %
2467 %                                                                             %
2468 %                                                                             %
2469 +   P r u n e C h i l d                                                       %
2470 %                                                                             %
2471 %                                                                             %
2472 %                                                                             %
2473 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2474 %
2475 %  PruneChild() deletes the given node and merges its statistics into its
2476 %  parent.
2477 %
2478 %  The format of the PruneSubtree method is:
2479 %
2480 %      PruneChild(CubeInfo *cube_info,const NodeInfo *node_info)
2481 %
2482 %  A description of each parameter follows.
2483 %
2484 %    o cube_info: A pointer to the Cube structure.
2485 %
2486 %    o node_info: pointer to node in color cube tree that is to be pruned.
2487 %
2488 */
2489 static void PruneChild(CubeInfo *cube_info,const NodeInfo *node_info)
2490 {
2491   NodeInfo
2492     *parent;
2493
2494   register ssize_t
2495     i;
2496
2497   size_t
2498     number_children;
2499
2500   /*
2501     Traverse any children.
2502   */
2503   number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2504   for (i=0; i < (ssize_t) number_children; i++)
2505     if (node_info->child[i] != (NodeInfo *) NULL)
2506       PruneChild(cube_info,node_info->child[i]);
2507   /*
2508     Merge color statistics into parent.
2509   */
2510   parent=node_info->parent;
2511   parent->number_unique+=node_info->number_unique;
2512   parent->total_color.red+=node_info->total_color.red;
2513   parent->total_color.green+=node_info->total_color.green;
2514   parent->total_color.blue+=node_info->total_color.blue;
2515   parent->total_color.alpha+=node_info->total_color.alpha;
2516   parent->child[node_info->id]=(NodeInfo *) NULL;
2517   cube_info->nodes--;
2518 }
2519 \f
2520 /*
2521 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2522 %                                                                             %
2523 %                                                                             %
2524 %                                                                             %
2525 +  P r u n e L e v e l                                                        %
2526 %                                                                             %
2527 %                                                                             %
2528 %                                                                             %
2529 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2530 %
2531 %  PruneLevel() deletes all nodes at the bottom level of the color tree merging
2532 %  their color statistics into their parent node.
2533 %
2534 %  The format of the PruneLevel method is:
2535 %
2536 %      PruneLevel(CubeInfo *cube_info,const NodeInfo *node_info)
2537 %
2538 %  A description of each parameter follows.
2539 %
2540 %    o cube_info: A pointer to the Cube structure.
2541 %
2542 %    o node_info: pointer to node in color cube tree that is to be pruned.
2543 %
2544 */
2545 static void PruneLevel(CubeInfo *cube_info,const NodeInfo *node_info)
2546 {
2547   register ssize_t
2548     i;
2549
2550   size_t
2551     number_children;
2552
2553   /*
2554     Traverse any children.
2555   */
2556   number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2557   for (i=0; i < (ssize_t) number_children; i++)
2558     if (node_info->child[i] != (NodeInfo *) NULL)
2559       PruneLevel(cube_info,node_info->child[i]);
2560   if (node_info->level == cube_info->depth)
2561     PruneChild(cube_info,node_info);
2562 }
2563 \f
2564 /*
2565 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2566 %                                                                             %
2567 %                                                                             %
2568 %                                                                             %
2569 +  P r u n e T o C u b e D e p t h                                            %
2570 %                                                                             %
2571 %                                                                             %
2572 %                                                                             %
2573 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2574 %
2575 %  PruneToCubeDepth() deletes any nodes at a depth greater than
2576 %  cube_info->depth while merging their color statistics into their parent
2577 %  node.
2578 %
2579 %  The format of the PruneToCubeDepth method is:
2580 %
2581 %      PruneToCubeDepth(CubeInfo *cube_info,const NodeInfo *node_info)
2582 %
2583 %  A description of each parameter follows.
2584 %
2585 %    o cube_info: A pointer to the Cube structure.
2586 %
2587 %    o node_info: pointer to node in color cube tree that is to be pruned.
2588 %
2589 */
2590 static void PruneToCubeDepth(CubeInfo *cube_info,const NodeInfo *node_info)
2591 {
2592   register ssize_t
2593     i;
2594
2595   size_t
2596     number_children;
2597
2598   /*
2599     Traverse any children.
2600   */
2601   number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2602   for (i=0; i < (ssize_t) number_children; i++)
2603     if (node_info->child[i] != (NodeInfo *) NULL)
2604       PruneToCubeDepth(cube_info,node_info->child[i]);
2605   if (node_info->level > cube_info->depth)
2606     PruneChild(cube_info,node_info);
2607 }
2608 \f
2609 /*
2610 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2611 %                                                                             %
2612 %                                                                             %
2613 %                                                                             %
2614 %  Q u a n t i z e I m a g e                                                  %
2615 %                                                                             %
2616 %                                                                             %
2617 %                                                                             %
2618 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2619 %
2620 %  QuantizeImage() analyzes the colors within a reference image and chooses a
2621 %  fixed number of colors to represent the image.  The goal of the algorithm
2622 %  is to minimize the color difference between the input and output image while
2623 %  minimizing the processing time.
2624 %
2625 %  The format of the QuantizeImage method is:
2626 %
2627 %      MagickBooleanType QuantizeImage(const QuantizeInfo *quantize_info,
2628 %        Image *image,ExceptionInfo *exception)
2629 %
2630 %  A description of each parameter follows:
2631 %
2632 %    o quantize_info: Specifies a pointer to an QuantizeInfo structure.
2633 %
2634 %    o image: the image.
2635 %
2636 %    o exception: return any errors or warnings in this structure.
2637 %
2638 */
2639 MagickExport MagickBooleanType QuantizeImage(const QuantizeInfo *quantize_info,
2640   Image *image,ExceptionInfo *exception)
2641 {
2642   CubeInfo
2643     *cube_info;
2644
2645   MagickBooleanType
2646     status;
2647
2648   size_t
2649     depth,
2650     maximum_colors;
2651
2652   assert(quantize_info != (const QuantizeInfo *) NULL);
2653   assert(quantize_info->signature == MagickCoreSignature);
2654   assert(image != (Image *) NULL);
2655   assert(image->signature == MagickCoreSignature);
2656   if (image->debug != MagickFalse)
2657     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
2658   assert(exception != (ExceptionInfo *) NULL);
2659   assert(exception->signature == MagickCoreSignature);
2660   maximum_colors=quantize_info->number_colors;
2661   if (maximum_colors == 0)
2662     maximum_colors=MaxColormapSize;
2663   if (maximum_colors > MaxColormapSize)
2664     maximum_colors=MaxColormapSize;
2665   if (image->alpha_trait != BlendPixelTrait)
2666     {
2667       if (SetImageGray(image,exception) != MagickFalse)
2668         (void) SetGrayscaleImage(image,exception);
2669     }
2670   if ((image->storage_class == PseudoClass) &&
2671       (image->colors <= maximum_colors))
2672     {
2673       if ((quantize_info->colorspace != UndefinedColorspace) &&
2674           (quantize_info->colorspace != CMYKColorspace))
2675         (void) TransformImageColorspace(image,quantize_info->colorspace,
2676           exception);
2677       return(MagickTrue);
2678     }
2679   depth=quantize_info->tree_depth;
2680   if (depth == 0)
2681     {
2682       size_t
2683         colors;
2684
2685       /*
2686         Depth of color tree is: Log4(colormap size)+2.
2687       */
2688       colors=maximum_colors;
2689       for (depth=1; colors != 0; depth++)
2690         colors>>=2;
2691       if ((quantize_info->dither_method != NoDitherMethod) && (depth > 2))
2692         depth--;
2693       if ((image->alpha_trait == BlendPixelTrait) && (depth > 5))
2694         depth--;
2695       if (SetImageGray(image,exception) != MagickFalse)
2696         depth=MaxTreeDepth;
2697     }
2698   /*
2699     Initialize color cube.
2700   */
2701   cube_info=GetCubeInfo(quantize_info,depth,maximum_colors);
2702   if (cube_info == (CubeInfo *) NULL)
2703     ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
2704       image->filename);
2705   status=ClassifyImageColors(cube_info,image,exception);
2706   if (status != MagickFalse)
2707     {
2708       /*
2709         Reduce the number of colors in the image if it contains more than the
2710         maximum, otherwise we can disable dithering to improve the performance.
2711       */
2712       if (cube_info->colors > cube_info->maximum_colors)
2713         ReduceImageColors(image,cube_info);
2714       else
2715         cube_info->quantize_info->dither_method=NoDitherMethod;
2716       status=AssignImageColors(image,cube_info,exception);
2717     }
2718   DestroyCubeInfo(cube_info);
2719   return(status);
2720 }
2721 \f
2722 /*
2723 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2724 %                                                                             %
2725 %                                                                             %
2726 %                                                                             %
2727 %   Q u a n t i z e I m a g e s                                               %
2728 %                                                                             %
2729 %                                                                             %
2730 %                                                                             %
2731 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2732 %
2733 %  QuantizeImages() analyzes the colors within a set of reference images and
2734 %  chooses a fixed number of colors to represent the set.  The goal of the
2735 %  algorithm is to minimize the color difference between the input and output
2736 %  images while minimizing the processing time.
2737 %
2738 %  The format of the QuantizeImages method is:
2739 %
2740 %      MagickBooleanType QuantizeImages(const QuantizeInfo *quantize_info,
2741 %        Image *images,ExceptionInfo *exception)
2742 %
2743 %  A description of each parameter follows:
2744 %
2745 %    o quantize_info: Specifies a pointer to an QuantizeInfo structure.
2746 %
2747 %    o images: Specifies a pointer to a list of Image structures.
2748 %
2749 %    o exception: return any errors or warnings in this structure.
2750 %
2751 */
2752 MagickExport MagickBooleanType QuantizeImages(const QuantizeInfo *quantize_info,
2753   Image *images,ExceptionInfo *exception)
2754 {
2755   CubeInfo
2756     *cube_info;
2757
2758   Image
2759     *image;
2760
2761   MagickBooleanType
2762     proceed,
2763     status;
2764
2765   MagickProgressMonitor
2766     progress_monitor;
2767
2768   register ssize_t
2769     i;
2770
2771   size_t
2772     depth,
2773     maximum_colors,
2774     number_images;
2775
2776   assert(quantize_info != (const QuantizeInfo *) NULL);
2777   assert(quantize_info->signature == MagickCoreSignature);
2778   assert(images != (Image *) NULL);
2779   assert(images->signature == MagickCoreSignature);
2780   if (images->debug != MagickFalse)
2781     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",images->filename);
2782   assert(exception != (ExceptionInfo *) NULL);
2783   assert(exception->signature == MagickCoreSignature);
2784   if (GetNextImageInList(images) == (Image *) NULL)
2785     {
2786       /*
2787         Handle a single image with QuantizeImage.
2788       */
2789       status=QuantizeImage(quantize_info,images,exception);
2790       return(status);
2791     }
2792   status=MagickFalse;
2793   maximum_colors=quantize_info->number_colors;
2794   if (maximum_colors == 0)
2795     maximum_colors=MaxColormapSize;
2796   if (maximum_colors > MaxColormapSize)
2797     maximum_colors=MaxColormapSize;
2798   depth=quantize_info->tree_depth;
2799   if (depth == 0)
2800     {
2801       size_t
2802         colors;
2803
2804       /*
2805         Depth of color tree is: Log4(colormap size)+2.
2806       */
2807       colors=maximum_colors;
2808       for (depth=1; colors != 0; depth++)
2809         colors>>=2;
2810       if (quantize_info->dither_method != NoDitherMethod)
2811         depth--;
2812     }
2813   /*
2814     Initialize color cube.
2815   */
2816   cube_info=GetCubeInfo(quantize_info,depth,maximum_colors);
2817   if (cube_info == (CubeInfo *) NULL)
2818     {
2819       (void) ThrowMagickException(exception,GetMagickModule(),
2820         ResourceLimitError,"MemoryAllocationFailed","`%s'",images->filename);
2821       return(MagickFalse);
2822     }
2823   number_images=GetImageListLength(images);
2824   image=images;
2825   for (i=0; image != (Image *) NULL; i++)
2826   {
2827     progress_monitor=SetImageProgressMonitor(image,(MagickProgressMonitor) NULL,
2828       image->client_data);
2829     status=ClassifyImageColors(cube_info,image,exception);
2830     if (status == MagickFalse)
2831       break;
2832     (void) SetImageProgressMonitor(image,progress_monitor,image->client_data);
2833     proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) i,
2834       number_images);
2835     if (proceed == MagickFalse)
2836       break;
2837     image=GetNextImageInList(image);
2838   }
2839   if (status != MagickFalse)
2840     {
2841       /*
2842         Reduce the number of colors in an image sequence.
2843       */
2844       ReduceImageColors(images,cube_info);
2845       image=images;
2846       for (i=0; image != (Image *) NULL; i++)
2847       {
2848         progress_monitor=SetImageProgressMonitor(image,(MagickProgressMonitor)
2849           NULL,image->client_data);
2850         status=AssignImageColors(image,cube_info,exception);
2851         if (status == MagickFalse)
2852           break;
2853         (void) SetImageProgressMonitor(image,progress_monitor,
2854           image->client_data);
2855         proceed=SetImageProgress(image,AssignImageTag,(MagickOffsetType) i,
2856           number_images);
2857         if (proceed == MagickFalse)
2858           break;
2859         image=GetNextImageInList(image);
2860       }
2861     }
2862   DestroyCubeInfo(cube_info);
2863   return(status);
2864 }
2865 \f
2866 /*
2867 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2868 %                                                                             %
2869 %                                                                             %
2870 %                                                                             %
2871 +   Q u a n t i z e E r r o r F l a t t e n                                   %
2872 %                                                                             %
2873 %                                                                             %
2874 %                                                                             %
2875 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2876 %
2877 %  QuantizeErrorFlatten() traverses the color cube and flattens the quantization
2878 %  error into a sorted 1D array.  This accelerates the color reduction process.
2879 %
2880 %  Contributed by Yoya.
2881 %
2882 %  The format of the QuantizeErrorFlatten method is:
2883 %
2884 %      size_t QuantizeErrorFlatten(const CubeInfo *cube_info,
2885 %        const NodeInfo *node_info,const ssize_t offset,
2886 %        double *quantize_error)
2887 %
2888 %  A description of each parameter follows.
2889 %
2890 %    o cube_info: A pointer to the Cube structure.
2891 %
2892 %    o node_info: pointer to node in color cube tree that is current pointer.
2893 %
2894 %    o offset: quantize error offset.
2895 %
2896 %    o quantize_error: the quantization error vector.
2897 %
2898 */
2899 static size_t QuantizeErrorFlatten(const CubeInfo *cube_info,
2900   const NodeInfo *node_info,const ssize_t offset,double *quantize_error)
2901 {
2902   register ssize_t
2903     i;
2904
2905   size_t
2906     n,
2907     number_children;
2908
2909   if (offset >= (ssize_t) cube_info->nodes)
2910     return(0);
2911   quantize_error[offset]=node_info->quantize_error;
2912   n=1;
2913   number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2914   for (i=0; i < (ssize_t) number_children ; i++)
2915     if (node_info->child[i] != (NodeInfo *) NULL)
2916       n+=QuantizeErrorFlatten(cube_info,node_info->child[i],offset+n,
2917         quantize_error);
2918   return(n);
2919 }
2920 \f
2921 /*
2922 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2923 %                                                                             %
2924 %                                                                             %
2925 %                                                                             %
2926 +   R e d u c e                                                               %
2927 %                                                                             %
2928 %                                                                             %
2929 %                                                                             %
2930 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2931 %
2932 %  Reduce() traverses the color cube tree and prunes any node whose
2933 %  quantization error falls below a particular threshold.
2934 %
2935 %  The format of the Reduce method is:
2936 %
2937 %      Reduce(CubeInfo *cube_info,const NodeInfo *node_info)
2938 %
2939 %  A description of each parameter follows.
2940 %
2941 %    o cube_info: A pointer to the Cube structure.
2942 %
2943 %    o node_info: pointer to node in color cube tree that is to be pruned.
2944 %
2945 */
2946 static void Reduce(CubeInfo *cube_info,const NodeInfo *node_info)
2947 {
2948   register ssize_t
2949     i;
2950
2951   size_t
2952     number_children;
2953
2954   /*
2955     Traverse any children.
2956   */
2957   number_children=cube_info->associate_alpha == MagickFalse ? 8UL : 16UL;
2958   for (i=0; i < (ssize_t) number_children; i++)
2959     if (node_info->child[i] != (NodeInfo *) NULL)
2960       Reduce(cube_info,node_info->child[i]);
2961   if (node_info->quantize_error <= cube_info->pruning_threshold)
2962     PruneChild(cube_info,node_info);
2963   else
2964     {
2965       /*
2966         Find minimum pruning threshold.
2967       */
2968       if (node_info->number_unique > 0)
2969         cube_info->colors++;
2970       if (node_info->quantize_error < cube_info->next_threshold)
2971         cube_info->next_threshold=node_info->quantize_error;
2972     }
2973 }
2974 \f
2975 /*
2976 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2977 %                                                                             %
2978 %                                                                             %
2979 %                                                                             %
2980 +   R e d u c e I m a g e C o l o r s                                         %
2981 %                                                                             %
2982 %                                                                             %
2983 %                                                                             %
2984 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2985 %
2986 %  ReduceImageColors() repeatedly prunes the tree until the number of nodes
2987 %  with n2 > 0 is less than or equal to the maximum number of colors allowed
2988 %  in the output image.  On any given iteration over the tree, it selects
2989 %  those nodes whose E value is minimal for pruning and merges their
2990 %  color statistics upward. It uses a pruning threshold, Ep, to govern
2991 %  node selection as follows:
2992 %
2993 %    Ep = 0
2994 %    while number of nodes with (n2 > 0) > required maximum number of colors
2995 %      prune all nodes such that E <= Ep
2996 %      Set Ep to minimum E in remaining nodes
2997 %
2998 %  This has the effect of minimizing any quantization error when merging
2999 %  two nodes together.
3000 %
3001 %  When a node to be pruned has offspring, the pruning procedure invokes
3002 %  itself recursively in order to prune the tree from the leaves upward.
3003 %  n2,  Sr, Sg,  and  Sb in a node being pruned are always added to the
3004 %  corresponding data in that node's parent.  This retains the pruned
3005 %  node's color characteristics for later averaging.
3006 %
3007 %  For each node, n2 pixels exist for which that node represents the
3008 %  smallest volume in RGB space containing those pixel's colors.  When n2
3009 %  > 0 the node will uniquely define a color in the output image. At the
3010 %  beginning of reduction,  n2 = 0  for all nodes except a the leaves of
3011 %  the tree which represent colors present in the input image.
3012 %
3013 %  The other pixel count, n1, indicates the total number of colors
3014 %  within the cubic volume which the node represents.  This includes n1 -
3015 %  n2  pixels whose colors should be defined by nodes at a lower level in
3016 %  the tree.
3017 %
3018 %  The format of the ReduceImageColors method is:
3019 %
3020 %      ReduceImageColors(const Image *image,CubeInfo *cube_info)
3021 %
3022 %  A description of each parameter follows.
3023 %
3024 %    o image: the image.
3025 %
3026 %    o cube_info: A pointer to the Cube structure.
3027 %
3028 */
3029
3030 static int QuantizeErrorCompare(const void *error_p,const void *error_q)
3031 {
3032   double
3033     *p,
3034     *q;
3035
3036   p=(double *) error_p;
3037   q=(double *) error_q;
3038   if (*p > *q)
3039     return(1);
3040   if (fabs(*q-*p) <= MagickEpsilon)
3041     return(0);
3042   return(-1);
3043 }
3044
3045 static void ReduceImageColors(const Image *image,CubeInfo *cube_info)
3046 {
3047 #define ReduceImageTag  "Reduce/Image"
3048
3049   MagickBooleanType
3050     proceed;
3051
3052   MagickOffsetType
3053     offset;
3054
3055   size_t
3056     span;
3057
3058   cube_info->next_threshold=0.0;
3059   if (cube_info->colors > cube_info->maximum_colors)
3060     {
3061       double
3062         *quantize_error;
3063
3064       /*
3065         Enable rapid reduction of the number of unique colors.
3066       */
3067       quantize_error=(double *) AcquireQuantumMemory(cube_info->nodes,
3068         sizeof(*quantize_error));
3069       if (quantize_error != (double *) NULL)
3070         {
3071           (void) QuantizeErrorFlatten(cube_info,cube_info->root,0,
3072             quantize_error);
3073           qsort(quantize_error,cube_info->nodes,sizeof(double),
3074             QuantizeErrorCompare);
3075           if (cube_info->nodes > (110*(cube_info->maximum_colors+1)/100))
3076             cube_info->next_threshold=quantize_error[cube_info->nodes-110*
3077               (cube_info->maximum_colors+1)/100];
3078           quantize_error=(double *) RelinquishMagickMemory(quantize_error);
3079         }
3080   }
3081   for (span=cube_info->colors; cube_info->colors > cube_info->maximum_colors; )
3082   {
3083     cube_info->pruning_threshold=cube_info->next_threshold;
3084     cube_info->next_threshold=cube_info->root->quantize_error-1;
3085     cube_info->colors=0;
3086     Reduce(cube_info,cube_info->root);
3087     offset=(MagickOffsetType) span-cube_info->colors;
3088     proceed=SetImageProgress(image,ReduceImageTag,offset,span-
3089       cube_info->maximum_colors+1);
3090     if (proceed == MagickFalse)
3091       break;
3092   }
3093 }
3094 \f
3095 /*
3096 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3097 %                                                                             %
3098 %                                                                             %
3099 %                                                                             %
3100 %   R e m a p I m a g e                                                       %
3101 %                                                                             %
3102 %                                                                             %
3103 %                                                                             %
3104 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3105 %
3106 %  RemapImage() replaces the colors of an image with the closest of the colors
3107 %  from the reference image.
3108 %
3109 %  The format of the RemapImage method is:
3110 %
3111 %      MagickBooleanType RemapImage(const QuantizeInfo *quantize_info,
3112 %        Image *image,const Image *remap_image,ExceptionInfo *exception)
3113 %
3114 %  A description of each parameter follows:
3115 %
3116 %    o quantize_info: Specifies a pointer to an QuantizeInfo structure.
3117 %
3118 %    o image: the image.
3119 %
3120 %    o remap_image: the reference image.
3121 %
3122 %    o exception: return any errors or warnings in this structure.
3123 %
3124 */
3125 MagickExport MagickBooleanType RemapImage(const QuantizeInfo *quantize_info,
3126   Image *image,const Image *remap_image,ExceptionInfo *exception)
3127 {
3128   CubeInfo
3129     *cube_info;
3130
3131   MagickBooleanType
3132     status;
3133
3134   /*
3135     Initialize color cube.
3136   */
3137   assert(image != (Image *) NULL);
3138   assert(image->signature == MagickCoreSignature);
3139   if (image->debug != MagickFalse)
3140     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
3141   assert(remap_image != (Image *) NULL);
3142   assert(remap_image->signature == MagickCoreSignature);
3143   assert(exception != (ExceptionInfo *) NULL);
3144   assert(exception->signature == MagickCoreSignature);
3145   cube_info=GetCubeInfo(quantize_info,MaxTreeDepth,
3146     quantize_info->number_colors);
3147   if (cube_info == (CubeInfo *) NULL)
3148     ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3149       image->filename);
3150   status=ClassifyImageColors(cube_info,remap_image,exception);
3151   if (status != MagickFalse)
3152     {
3153       /*
3154         Classify image colors from the reference image.
3155       */
3156       cube_info->quantize_info->number_colors=cube_info->colors;
3157       status=AssignImageColors(image,cube_info,exception);
3158     }
3159   DestroyCubeInfo(cube_info);
3160   return(status);
3161 }
3162 \f
3163 /*
3164 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3165 %                                                                             %
3166 %                                                                             %
3167 %                                                                             %
3168 %   R e m a p I m a g e s                                                     %
3169 %                                                                             %
3170 %                                                                             %
3171 %                                                                             %
3172 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3173 %
3174 %  RemapImages() replaces the colors of a sequence of images with the
3175 %  closest color from a reference image.
3176 %
3177 %  The format of the RemapImage method is:
3178 %
3179 %      MagickBooleanType RemapImages(const QuantizeInfo *quantize_info,
3180 %        Image *images,Image *remap_image,ExceptionInfo *exception)
3181 %
3182 %  A description of each parameter follows:
3183 %
3184 %    o quantize_info: Specifies a pointer to an QuantizeInfo structure.
3185 %
3186 %    o images: the image sequence.
3187 %
3188 %    o remap_image: the reference image.
3189 %
3190 %    o exception: return any errors or warnings in this structure.
3191 %
3192 */
3193 MagickExport MagickBooleanType RemapImages(const QuantizeInfo *quantize_info,
3194   Image *images,const Image *remap_image,ExceptionInfo *exception)
3195 {
3196   CubeInfo
3197     *cube_info;
3198
3199   Image
3200     *image;
3201
3202   MagickBooleanType
3203     status;
3204
3205   assert(images != (Image *) NULL);
3206   assert(images->signature == MagickCoreSignature);
3207   if (images->debug != MagickFalse)
3208     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",images->filename);
3209   assert(exception != (ExceptionInfo *) NULL);
3210   assert(exception->signature == MagickCoreSignature);
3211   image=images;
3212   if (remap_image == (Image *) NULL)
3213     {
3214       /*
3215         Create a global colormap for an image sequence.
3216       */
3217       status=QuantizeImages(quantize_info,images,exception);
3218       return(status);
3219     }
3220   /*
3221     Classify image colors from the reference image.
3222   */
3223   cube_info=GetCubeInfo(quantize_info,MaxTreeDepth,
3224     quantize_info->number_colors);
3225   if (cube_info == (CubeInfo *) NULL)
3226     ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3227       image->filename);
3228   status=ClassifyImageColors(cube_info,remap_image,exception);
3229   if (status != MagickFalse)
3230     {
3231       /*
3232         Classify image colors from the reference image.
3233       */
3234       cube_info->quantize_info->number_colors=cube_info->colors;
3235       image=images;
3236       for ( ; image != (Image *) NULL; image=GetNextImageInList(image))
3237       {
3238         status=AssignImageColors(image,cube_info,exception);
3239         if (status == MagickFalse)
3240           break;
3241       }
3242     }
3243   DestroyCubeInfo(cube_info);
3244   return(status);
3245 }
3246 \f
3247 /*
3248 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3249 %                                                                             %
3250 %                                                                             %
3251 %                                                                             %
3252 %   S e t G r a y s c a l e I m a g e                                         %
3253 %                                                                             %
3254 %                                                                             %
3255 %                                                                             %
3256 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3257 %
3258 %  SetGrayscaleImage() converts an image to a PseudoClass grayscale image.
3259 %
3260 %  The format of the SetGrayscaleImage method is:
3261 %
3262 %      MagickBooleanType SetGrayscaleImage(Image *image,
3263 %        ExceptionInfo *exception)
3264 %
3265 %  A description of each parameter follows:
3266 %
3267 %    o image: The image.
3268 %
3269 %    o exception: return any errors or warnings in this structure.
3270 %
3271 */
3272
3273 #if defined(__cplusplus) || defined(c_plusplus)
3274 extern "C" {
3275 #endif
3276
3277 static int IntensityCompare(const void *x,const void *y)
3278 {
3279   double
3280     intensity;
3281
3282   PixelInfo
3283     *color_1,
3284     *color_2;
3285
3286   color_1=(PixelInfo *) x;
3287   color_2=(PixelInfo *) y;
3288   intensity=GetPixelInfoIntensity((const Image *) NULL,color_1)-
3289     GetPixelInfoIntensity((const Image *) NULL,color_2);
3290   return((int) intensity);
3291 }
3292
3293 #if defined(__cplusplus) || defined(c_plusplus)
3294 }
3295 #endif
3296
3297 static MagickBooleanType SetGrayscaleImage(Image *image,
3298   ExceptionInfo *exception)
3299 {
3300   CacheView
3301     *image_view;
3302
3303   MagickBooleanType
3304     status;
3305
3306   PixelInfo
3307     *colormap;
3308
3309   register ssize_t
3310     i;
3311
3312   ssize_t
3313     *colormap_index,
3314     j,
3315     y;
3316
3317   assert(image != (Image *) NULL);
3318   assert(image->signature == MagickCoreSignature);
3319   if (image->type != GrayscaleType)
3320     (void) TransformImageColorspace(image,GRAYColorspace,exception);
3321   colormap_index=(ssize_t *) AcquireQuantumMemory(MaxColormapSize,
3322     sizeof(*colormap_index));
3323   if (colormap_index == (ssize_t *) NULL)
3324     ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3325       image->filename);
3326   if (image->storage_class != PseudoClass)
3327     {
3328       (void) ResetMagickMemory(colormap_index,(-1),MaxColormapSize*
3329         sizeof(*colormap_index));
3330       if (AcquireImageColormap(image,MaxColormapSize,exception) == MagickFalse)
3331         {
3332           colormap_index=(ssize_t *) RelinquishMagickMemory(colormap_index);
3333           ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3334             image->filename);
3335         }
3336       image->colors=0;
3337       status=MagickTrue;
3338       image_view=AcquireAuthenticCacheView(image,exception);
3339 #if defined(MAGICKCORE_OPENMP_SUPPORT)
3340       #pragma omp parallel for schedule(static,4) shared(status) \
3341         magick_number_threads(image,image,image->rows,1)
3342 #endif
3343       for (y=0; y < (ssize_t) image->rows; y++)
3344       {
3345         register Quantum
3346           *magick_restrict q;
3347
3348         register ssize_t
3349           x;
3350
3351         if (status == MagickFalse)
3352           continue;
3353         q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,
3354           exception);
3355         if (q == (Quantum *) NULL)
3356           {
3357             status=MagickFalse;
3358             continue;
3359           }
3360         for (x=0; x < (ssize_t) image->columns; x++)
3361         {
3362           register size_t
3363             intensity;
3364
3365           intensity=ScaleQuantumToMap(GetPixelRed(image,q));
3366           if (colormap_index[intensity] < 0)
3367             {
3368 #if defined(MAGICKCORE_OPENMP_SUPPORT)
3369               #pragma omp critical (MagickCore_SetGrayscaleImage)
3370 #endif
3371               if (colormap_index[intensity] < 0)
3372                 {
3373                   colormap_index[intensity]=(ssize_t) image->colors;
3374                   image->colormap[image->colors].red=(double)
3375                     GetPixelRed(image,q);
3376                   image->colormap[image->colors].green=(double)
3377                     GetPixelGreen(image,q);
3378                   image->colormap[image->colors].blue=(double)
3379                     GetPixelBlue(image,q);
3380                   image->colors++;
3381                }
3382             }
3383           SetPixelIndex(image,(Quantum) colormap_index[intensity],q);
3384           q+=GetPixelChannels(image);
3385         }
3386         if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
3387           status=MagickFalse;
3388       }
3389       image_view=DestroyCacheView(image_view);
3390     }
3391   for (i=0; i < (ssize_t) image->colors; i++)
3392     image->colormap[i].alpha=(double) i;
3393   qsort((void *) image->colormap,image->colors,sizeof(PixelInfo),
3394     IntensityCompare);
3395   colormap=(PixelInfo *) AcquireQuantumMemory(image->colors,sizeof(*colormap));
3396   if (colormap == (PixelInfo *) NULL)
3397     {
3398       colormap_index=(ssize_t *) RelinquishMagickMemory(colormap_index);
3399       ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
3400         image->filename);
3401     }
3402   j=0;
3403   colormap[j]=image->colormap[0];
3404   for (i=0; i < (ssize_t) image->colors; i++)
3405   {
3406     if (IsPixelInfoEquivalent(&colormap[j],&image->colormap[i]) == MagickFalse)
3407       {
3408         j++;
3409         colormap[j]=image->colormap[i];
3410       }
3411     colormap_index[(ssize_t) image->colormap[i].alpha]=j;
3412   }
3413   image->colors=(size_t) (j+1);
3414   image->colormap=(PixelInfo *) RelinquishMagickMemory(image->colormap);
3415   image->colormap=colormap;
3416   status=MagickTrue;
3417   image_view=AcquireAuthenticCacheView(image,exception);
3418 #if defined(MAGICKCORE_OPENMP_SUPPORT)
3419   #pragma omp parallel for schedule(static,4) shared(status) \
3420     magick_number_threads(image,image,image->rows,1)
3421 #endif
3422   for (y=0; y < (ssize_t) image->rows; y++)
3423   {
3424     register Quantum
3425       *magick_restrict q;
3426
3427     register ssize_t
3428       x;
3429
3430     if (status == MagickFalse)
3431       continue;
3432     q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
3433     if (q == (Quantum *) NULL)
3434       {
3435         status=MagickFalse;
3436         continue;
3437       }
3438     for (x=0; x < (ssize_t) image->columns; x++)
3439     {
3440       SetPixelIndex(image,(Quantum) colormap_index[ScaleQuantumToMap(
3441         GetPixelIndex(image,q))],q);
3442       q+=GetPixelChannels(image);
3443     }
3444     if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
3445       status=MagickFalse;
3446   }
3447   image_view=DestroyCacheView(image_view);
3448   colormap_index=(ssize_t *) RelinquishMagickMemory(colormap_index);
3449   image->type=GrayscaleType;
3450   if (SetImageMonochrome(image,exception) != MagickFalse)
3451     image->type=BilevelType;
3452   return(status);
3453 }