colormap.c

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/*
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%                        MagickCore Colormap Methods                          %
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%                              Software Design                                %
%                                   Cristy                                    %
%                                 July 1992                                   %
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%  Copyright 1999-2021 ImageMagick Studio LLC, a non-profit organization      %
%  dedicated to making software imaging solutions freely available.           %
%                                                                             %
%  You may not use this file except in compliance with the License.  You may  %
%  obtain a copy of the License at                                            %
%                                                                             %
%    https://imagemagick.org/script/license.php                               %
%                                                                             %
%  Unless required by applicable law or agreed to in writing, software        %
%  distributed under the License is distributed on an "AS IS" BASIS,          %
%  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   %
%  See the License for the specific language governing permissions and        %
%  limitations under the License.                                             %
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%  We use linked-lists because splay-trees do not currently support duplicate
%  key / value pairs (.e.g X11 green compliance and SVG green compliance).
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*/

/*
  Include declarations.
*/
#include "MagickCore/studio.h"
#include "MagickCore/attribute.h"
#include "MagickCore/blob.h"
#include "MagickCore/cache-view.h"
#include "MagickCore/cache.h"
#include "MagickCore/color.h"
#include "MagickCore/color-private.h"
#include "MagickCore/colormap.h"
#include "MagickCore/colormap-private.h"
#include "MagickCore/client.h"
#include "MagickCore/configure.h"
#include "MagickCore/exception.h"
#include "MagickCore/exception-private.h"
#include "MagickCore/gem.h"
#include "MagickCore/geometry.h"
#include "MagickCore/image-private.h"
#include "MagickCore/memory_.h"
#include "MagickCore/monitor.h"
#include "MagickCore/monitor-private.h"
#include "MagickCore/option.h"
#include "MagickCore/pixel-accessor.h"
#include "MagickCore/quantize.h"
#include "MagickCore/quantum.h"
#include "MagickCore/resource_.h"
#include "MagickCore/semaphore.h"
#include "MagickCore/string_.h"
#include "MagickCore/thread-private.h"
#include "MagickCore/token.h"
#include "MagickCore/utility.h"
#include "MagickCore/xml-tree.h"

/*
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%   A c q u i r e I m a g e C o l o r m a p                                   %
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%  AcquireImageColormap() allocates an image colormap and initializes
%  it to a linear gray colorspace.  If the image already has a colormap,
%  it is replaced.  AcquireImageColormap() returns MagickTrue if successful,
%  otherwise MagickFalse if there is not enough memory.
%
%  The format of the AcquireImageColormap method is:
%
%      MagickBooleanType AcquireImageColormap(Image *image,const size_t colors,
%        ExceptionInfo *exception)
%
%  A description of each parameter follows:
%
%    o image: the image.
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%    o colors: the number of colors in the image colormap.
%
%    o exception: return any errors or warnings in this structure.
%
*/
MagickExport MagickBooleanType AcquireImageColormap(Image *image,
  const size_t colors,ExceptionInfo *exception)
{
  ssize_t
    i;

  /*
    Allocate image colormap.
  */
  assert(image != (Image *) NULL);
  assert(image->signature == MagickCoreSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  if (colors > MaxColormapSize)
    {
      image->colors=0;
      image->storage_class=DirectClass;
      ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
        image->filename);
    }
  image->colors=MagickMax(colors,1);
  if (image->colormap == (PixelInfo *) NULL)
    image->colormap=(PixelInfo *) AcquireQuantumMemory(image->colors+1,
      sizeof(*image->colormap));
  else
    image->colormap=(PixelInfo *) ResizeQuantumMemory(image->colormap,
      image->colors+1,sizeof(*image->colormap));
  if (image->colormap == (PixelInfo *) NULL)
    {
      image->colors=0;
      image->storage_class=DirectClass;
      ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
        image->filename);
    }
  for (i=0; i < (ssize_t) image->colors; i++)
  {
    double
      pixel;

    GetPixelInfo(image,image->colormap+i);
    pixel=(double) (i*(QuantumRange/MagickMax(colors-1,1)));
    image->colormap[i].red=pixel;
    image->colormap[i].green=pixel;
    image->colormap[i].blue=pixel;
    image->colormap[i].alpha=(MagickRealType) OpaqueAlpha;
    image->colormap[i].alpha_trait=BlendPixelTrait;
  }
  return(SetImageStorageClass(image,PseudoClass,exception));
}

/*
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%     C y c l e C o l o r m a p I m a g e                                     %
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%  CycleColormap() displaces an image's colormap by a given number of
%  positions.  If you cycle the colormap a number of times you can produce
%  a psychodelic effect.
%
%  WARNING: this assumes an images colormap is in a well know and defined
%  order. Currently Imagemagick has no way of setting that order.
%
%  The format of the CycleColormapImage method is:
%
%      MagickBooleanType CycleColormapImage(Image *image,const ssize_t displace,
%        ExceptionInfo *exception)
%
%  A description of each parameter follows:
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%    o image: the image.
%
%    o displace:  displace the colormap this amount.
%
%    o exception: return any errors or warnings in this structure.
%
*/
MagickExport MagickBooleanType CycleColormapImage(Image *image,
  const ssize_t displace,ExceptionInfo *exception)
{
  CacheView
    *image_view;

  MagickBooleanType
    status;

  ssize_t
    y;

  assert(image != (Image *) NULL);
  assert(image->signature == MagickCoreSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  if (image->storage_class == DirectClass)
    (void) SetImageType(image,PaletteType,exception);
  status=MagickTrue;
  image_view=AcquireAuthenticCacheView(image,exception);
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(static) \
    magick_number_threads(image,image,image->rows,1)
#endif
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    ssize_t
      x;

    Quantum
      *magick_restrict q;

    ssize_t
      index;

    if (status == MagickFalse)
      continue;
    q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
    if (q == (Quantum *) NULL)
      {
        status=MagickFalse;
        continue;
      }
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      index=(ssize_t) (GetPixelIndex(image,q)+displace) % image->colors;
      if (index < 0)
        index+=(ssize_t) image->colors;
      SetPixelIndex(image,(Quantum) index,q);
      SetPixelViaPixelInfo(image,image->colormap+(ssize_t) index,q);
      q+=GetPixelChannels(image);
    }
    if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
      status=MagickFalse;
  }
  image_view=DestroyCacheView(image_view);
  return(status);
}

/*
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+   S o r t C o l o r m a p B y I n t e n s i t y                             %
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%  SortColormapByIntensity() sorts the colormap of a PseudoClass image by
%  decreasing color intensity.
%
%  The format of the SortColormapByIntensity method is:
%
%      MagickBooleanType SortColormapByIntensity(Image *image,
%        ExceptionInfo *exception)
%
%  A description of each parameter follows:
%
%    o image: A pointer to an Image structure.
%
%    o exception: return any errors or warnings in this structure.
%
*/

#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif

static int IntensityCompare(const void *x,const void *y)
{
  const PixelInfo
    *color_1,
    *color_2;

  int
    intensity;

  color_1=(const PixelInfo *) x;
  color_2=(const PixelInfo *) y;
  intensity=(int) GetPixelInfoIntensity((const Image *) NULL,color_2)-(int)
    GetPixelInfoIntensity((const Image *) NULL,color_1);
  return(intensity);
}

#if defined(__cplusplus) || defined(c_plusplus)
}
#endif

MagickExport MagickBooleanType SortColormapByIntensity(Image *image,
  ExceptionInfo *exception)
{
  CacheView
    *image_view;

  MagickBooleanType
    status;

  ssize_t
    i;

  ssize_t
    y;

  unsigned short
    *pixels;

  assert(image != (Image *) NULL);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"...");
  assert(image->signature == MagickCoreSignature);
  if (image->storage_class != PseudoClass)
    return(MagickTrue);
  /*
    Allocate memory for pixel indexes.
  */
  pixels=(unsigned short *) AcquireQuantumMemory((size_t) image->colors,
    sizeof(*pixels));
  if (pixels == (unsigned short *) NULL)
    ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
      image->filename);
  /*
    Assign index values to colormap entries.
  */
  for (i=0; i < (ssize_t) image->colors; i++)
    image->colormap[i].alpha=(double) i;
  /*
    Sort image colormap by decreasing color popularity.
  */
  qsort((void *) image->colormap,(size_t) image->colors,
    sizeof(*image->colormap),IntensityCompare);
  /*
    Update image colormap indexes to sorted colormap order.
  */
  for (i=0; i < (ssize_t) image->colors; i++)
    pixels[(ssize_t) image->colormap[i].alpha]=(unsigned short) i;
  status=MagickTrue;
  image_view=AcquireAuthenticCacheView(image,exception);
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    Quantum
      index;

    ssize_t
      x;

    Quantum
      *magick_restrict q;

    q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
    if (q == (Quantum *) NULL)
      {
        status=MagickFalse;
        break;
      }
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      i=ConstrainColormapIndex(image,GetPixelIndex(image,q),exception);
      index=(Quantum) pixels[i];
      SetPixelIndex(image,index,q);
      SetPixelViaPixelInfo(image,image->colormap+(ssize_t) index,q);
      q+=GetPixelChannels(image);
    }
    if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
      status=MagickFalse;
    if (status == MagickFalse)
      break;
  }
  image_view=DestroyCacheView(image_view);
  pixels=(unsigned short *) RelinquishMagickMemory(pixels);
  return(status);
}