root/magick/enhance.c

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DEFINITIONS

This source file includes following definitions.
  1. AutoGammaImage
  2. AutoGammaImageChannel
  3. AutoLevelImage
  4. AutoLevelImageChannel
  5. BrightnessContrastImage
  6. BrightnessContrastImageChannel
  7. ColorDecisionListImage
  8. ClutImage
  9. ClutImageChannel
  10. Contrast
  11. ContrastImage
  12. ContrastStretchImage
  13. ContrastStretchImageChannel
  14. EnhanceImage
  15. EqualizeImage
  16. EqualizeImageChannel
  17. GammaImage
  18. GammaImageChannel
  19. MagickMin
  20. HaldClutImage
  21. HaldClutImageChannel
  22. LevelImage
  23. LevelImageChannel
  24. LevelizeImage
  25. LevelizeImageChannel
  26. LevelColorsImage
  27. LevelColorsImageChannel
  28. LinearStretchImage
  29. ModulateHSB
  30. ModulateHSL
  31. ModulateHWB
  32. ModulateImage
  33. NegateImage
  34. NegateImageChannel
  35. NormalizeImage
  36. NormalizeImageChannel
  37. SigmoidalContrastImage
  38. SigmoidalContrastImageChannel

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%              EEEEE  N   N  H   H   AAA   N   N   CCCC  EEEEE                %
%              E      NN  N  H   H  A   A  NN  N  C      E                    %
%              EEE    N N N  HHHHH  AAAAA  N N N  C      EEE                  %
%              E      N  NN  H   H  A   A  N  NN  C      E                    %
%              EEEEE  N   N  H   H  A   A  N   N   CCCC  EEEEE                %
%                                                                             %
%                                                                             %
%                    MagickCore Image Enhancement Methods                     %
%                                                                             %
%                              Software Design                                %
%                                John Cristy                                  %
%                                 July 1992                                   %
%                                                                             %
%                                                                             %
%  Copyright 1999-2011 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                                            %
%                                                                             %
%    http://www.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.                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%
%
*/

/*
  Include declarations.
*/
#include "magick/studio.h"
#include "magick/artifact.h"
#include "magick/cache.h"
#include "magick/cache-view.h"
#include "magick/color.h"
#include "magick/color-private.h"
#include "magick/colorspace.h"
#include "magick/composite-private.h"
#include "magick/enhance.h"
#include "magick/exception.h"
#include "magick/exception-private.h"
#include "magick/fx.h"
#include "magick/gem.h"
#include "magick/geometry.h"
#include "magick/histogram.h"
#include "magick/image.h"
#include "magick/image-private.h"
#include "magick/memory_.h"
#include "magick/monitor.h"
#include "magick/monitor-private.h"
#include "magick/option.h"
#include "magick/pixel-private.h"
#include "magick/quantum.h"
#include "magick/quantum-private.h"
#include "magick/resample.h"
#include "magick/resample-private.h"
#include "magick/statistic.h"
#include "magick/string_.h"
#include "magick/string-private.h"
#include "magick/thread-private.h"
#include "magick/token.h"
#include "magick/xml-tree.h"

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%     A u t o G a m m a I m a g e                                             %
%                                                                             %
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  AutoGammaImage() extract the 'mean' from the image and adjust the image
%  to try make set its gamma appropriatally.
%
%  The format of the AutoGammaImage method is:
%
%      MagickBooleanType AutoGammaImage(Image *image)
%      MagickBooleanType AutoGammaImageChannel(Image *image,
%        const ChannelType channel)
%
%  A description of each parameter follows:
%
%    o image: The image to auto-level
%
%    o channel: The channels to auto-level.  If the special 'SyncChannels'
%      flag is set all given channels is adjusted in the same way using the
%      mean average of those channels.
%
*/

MagickExport MagickBooleanType AutoGammaImage(Image *image)
{
  return(AutoGammaImageChannel(image,DefaultChannels));
}

MagickExport MagickBooleanType AutoGammaImageChannel(Image *image,
  const ChannelType channel)
{
  MagickStatusType
    status;

  double
    mean,sans,gamma,logmean;

  logmean=log(0.5);

  if ((channel & SyncChannels) != 0 )
    {
      /*
        Apply gamma correction equally accross all given channels
      */
      (void) GetImageChannelMean(image,channel,&mean,&sans,&image->exception);
      gamma=log(mean*QuantumScale)/logmean;
      return LevelImageChannel(image, channel,
                               0.0, (double)QuantumRange, gamma);
    }

  /*
    auto-gamma each channel separateally
  */
  status = MagickTrue;
  if ((channel & RedChannel) != 0)
    {
      (void) GetImageChannelMean(image,RedChannel,&mean,&sans,
        &image->exception);
      gamma=log(mean*QuantumScale)/logmean;
      status = status && LevelImageChannel(image, RedChannel,
                               0.0, (double)QuantumRange, gamma);
    }
  if ((channel & GreenChannel) != 0)
    {
      (void) GetImageChannelMean(image,GreenChannel,&mean,&sans,
        &image->exception);
      gamma=log(mean*QuantumScale)/logmean;
      status = status && LevelImageChannel(image, GreenChannel,
                               0.0, (double)QuantumRange, gamma);
    }
  if ((channel & BlueChannel) != 0)
    {
      (void) GetImageChannelMean(image,BlueChannel,&mean,&sans,
        &image->exception);
      gamma=log(mean*QuantumScale)/logmean;
      status = status && LevelImageChannel(image, BlueChannel,
                               0.0, (double)QuantumRange, gamma);
    }
  if (((channel & OpacityChannel) != 0) &&
      (image->matte == MagickTrue))
    {
      (void) GetImageChannelMean(image,OpacityChannel,&mean,&sans,
        &image->exception);
      gamma=log(mean*QuantumScale)/logmean;
      status = status && LevelImageChannel(image, OpacityChannel,
                               0.0, (double)QuantumRange, gamma);
    }
  if (((channel & IndexChannel) != 0) &&
      (image->colorspace == CMYKColorspace))
    {
      (void) GetImageChannelMean(image,IndexChannel,&mean,&sans,
        &image->exception);
      gamma=log(mean*QuantumScale)/logmean;
      status = status && LevelImageChannel(image, IndexChannel,
                               0.0, (double)QuantumRange, gamma);
    }
  return(status != 0 ? MagickTrue : MagickFalse);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%     A u t o L e v e l I m a g e                                             %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  AutoLevelImage() adjusts the levels of a particular image channel by
%  scaling the minimum and maximum values to the full quantum range.
%
%  The format of the LevelImage method is:
%
%      MagickBooleanType AutoLevelImage(Image *image)
%      MagickBooleanType AutoLevelImageChannel(Image *image,
%        const ChannelType channel)
%
%  A description of each parameter follows:
%
%    o image: The image to auto-level
%
%    o channel: The channels to auto-level.  If the special 'SyncChannels'
%      flag is set the min/max/mean value of all given channels is used for
%      all given channels, to all channels in the same way.
%
*/

MagickExport MagickBooleanType AutoLevelImage(Image *image)
{
  return(AutoLevelImageChannel(image,DefaultChannels));
}

MagickExport MagickBooleanType AutoLevelImageChannel(Image *image,
  const ChannelType channel)
{
  /*
    This is simply a convenience function around a Min/Max Histogram Stretch
  */
  return MinMaxStretchImage(image, channel, 0.0, 0.0);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%     B r i g h t n e s s C o n t r a s t I m a g e                           %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  Use BrightnessContrastImage() to change the brightness and/or contrast of
%  an image.  It converts the brightness and contrast parameters into slope
%  and intercept and calls a polynomical function to apply to the image.
%
%  The format of the BrightnessContrastImage method is:
%
%      MagickBooleanType BrightnessContrastImage(Image *image,
%        const double brightness,const double contrast)
%      MagickBooleanType BrightnessContrastImageChannel(Image *image,
%        const ChannelType channel,const double brightness,
%        const double contrast)
%
%  A description of each parameter follows:
%
%    o image: the image.
%
%    o channel: the channel.
%
%    o brightness: the brightness percent (-100 .. 100).
%
%    o contrast: the contrast percent (-100 .. 100).
%
*/

MagickExport MagickBooleanType BrightnessContrastImage(Image *image,
  const double brightness,const double contrast)
{
  MagickBooleanType
    status;

  status=BrightnessContrastImageChannel(image,DefaultChannels,brightness,
    contrast);
  return(status);
}

MagickExport MagickBooleanType BrightnessContrastImageChannel(Image *image,
  const ChannelType channel,const double brightness,const double contrast)
{
#define BrightnessContastImageTag  "BrightnessContast/Image"

  double
    alpha,
    intercept,
    coefficients[2],
    slope;

  MagickBooleanType
    status;

  /*
    Compute slope and intercept.
  */
  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  alpha=contrast;
  slope=tan((double) (MagickPI*(alpha/100.0+1.0)/4.0));
  if (slope < 0.0)
    slope=0.0;
  intercept=brightness/100.0+((100-brightness)/200.0)*(1.0-slope);
  coefficients[0]=slope;
  coefficients[1]=intercept;
  status=FunctionImageChannel(image,channel,PolynomialFunction,2,coefficients,
    &image->exception);
  return(status);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
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%                                                                             %
%     C o l o r D e c i s i o n L i s t I m a g e                             %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  ColorDecisionListImage() accepts a lightweight Color Correction Collection
%  (CCC) file which solely contains one or more color corrections and applies
%  the correction to the image.  Here is a sample CCC file:
%
%    <ColorCorrectionCollection xmlns="urn:ASC:CDL:v1.2">
%          <ColorCorrection id="cc03345">
%                <SOPNode>
%                     <Slope> 0.9 1.2 0.5 </Slope>
%                     <Offset> 0.4 -0.5 0.6 </Offset>
%                     <Power> 1.0 0.8 1.5 </Power>
%                </SOPNode>
%                <SATNode>
%                     <Saturation> 0.85 </Saturation>
%                </SATNode>
%          </ColorCorrection>
%    </ColorCorrectionCollection>
%
%  which includes the slop, offset, and power for each of the RGB channels
%  as well as the saturation.
%
%  The format of the ColorDecisionListImage method is:
%
%      MagickBooleanType ColorDecisionListImage(Image *image,
%        const char *color_correction_collection)
%
%  A description of each parameter follows:
%
%    o image: the image.
%
%    o color_correction_collection: the color correction collection in XML.
%
*/
MagickExport MagickBooleanType ColorDecisionListImage(Image *image,
  const char *color_correction_collection)
{
#define ColorDecisionListCorrectImageTag  "ColorDecisionList/Image"

  typedef struct _Correction
  {
    double
      slope,
      offset,
      power;
  } Correction;

  typedef struct _ColorCorrection
  {
    Correction
      red,
      green,
      blue;

    double
      saturation;
  } ColorCorrection;

  CacheView
    *image_view;

  char
    token[MaxTextExtent];

  ColorCorrection
    color_correction;

  const char
    *content,
    *p;

  ExceptionInfo
    *exception;

  MagickBooleanType
    status;

  MagickOffsetType
    progress;

  PixelPacket
    *cdl_map;

  register ssize_t
    i;

  ssize_t
    y;

  XMLTreeInfo
    *cc,
    *ccc,
    *sat,
    *sop;

  /*
    Allocate and initialize cdl maps.
  */
  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  if (color_correction_collection == (const char *) NULL)
    return(MagickFalse);
  ccc=NewXMLTree((const char *) color_correction_collection,&image->exception);
  if (ccc == (XMLTreeInfo *) NULL)
    return(MagickFalse);
  cc=GetXMLTreeChild(ccc,"ColorCorrection");
  if (cc == (XMLTreeInfo *) NULL)
    {
      ccc=DestroyXMLTree(ccc);
      return(MagickFalse);
    }
  color_correction.red.slope=1.0;
  color_correction.red.offset=0.0;
  color_correction.red.power=1.0;
  color_correction.green.slope=1.0;
  color_correction.green.offset=0.0;
  color_correction.green.power=1.0;
  color_correction.blue.slope=1.0;
  color_correction.blue.offset=0.0;
  color_correction.blue.power=1.0;
  color_correction.saturation=0.0;
  sop=GetXMLTreeChild(cc,"SOPNode");
  if (sop != (XMLTreeInfo *) NULL)
    {
      XMLTreeInfo
        *offset,
        *power,
        *slope;

      slope=GetXMLTreeChild(sop,"Slope");
      if (slope != (XMLTreeInfo *) NULL)
        {
          content=GetXMLTreeContent(slope);
          p=(const char *) content;
          for (i=0; (*p != '\0') && (i < 3); i++)
          {
            GetMagickToken(p,&p,token);
            if (*token == ',')
              GetMagickToken(p,&p,token);
            switch (i)
            {
              case 0: color_correction.red.slope=StringToDouble(token); break;
              case 1: color_correction.green.slope=StringToDouble(token); break;
              case 2: color_correction.blue.slope=StringToDouble(token); break;
            }
          }
        }
      offset=GetXMLTreeChild(sop,"Offset");
      if (offset != (XMLTreeInfo *) NULL)
        {
          content=GetXMLTreeContent(offset);
          p=(const char *) content;
          for (i=0; (*p != '\0') && (i < 3); i++)
          {
            GetMagickToken(p,&p,token);
            if (*token == ',')
              GetMagickToken(p,&p,token);
            switch (i)
            {
              case 0: color_correction.red.offset=StringToDouble(token); break;
              case 1: color_correction.green.offset=StringToDouble(token); break;
              case 2: color_correction.blue.offset=StringToDouble(token); break;
            }
          }
        }
      power=GetXMLTreeChild(sop,"Power");
      if (power != (XMLTreeInfo *) NULL)
        {
          content=GetXMLTreeContent(power);
          p=(const char *) content;
          for (i=0; (*p != '\0') && (i < 3); i++)
          {
            GetMagickToken(p,&p,token);
            if (*token == ',')
              GetMagickToken(p,&p,token);
            switch (i)
            {
              case 0: color_correction.red.power=StringToDouble(token); break;
              case 1: color_correction.green.power=StringToDouble(token); break;
              case 2: color_correction.blue.power=StringToDouble(token); break;
            }
          }
        }
    }
  sat=GetXMLTreeChild(cc,"SATNode");
  if (sat != (XMLTreeInfo *) NULL)
    {
      XMLTreeInfo
        *saturation;

      saturation=GetXMLTreeChild(sat,"Saturation");
      if (saturation != (XMLTreeInfo *) NULL)
        {
          content=GetXMLTreeContent(saturation);
          p=(const char *) content;
          GetMagickToken(p,&p,token);
          color_correction.saturation=StringToDouble(token);
        }
    }
  ccc=DestroyXMLTree(ccc);
  if (image->debug != MagickFalse)
    {
      (void) LogMagickEvent(TransformEvent,GetMagickModule(),
        "  Color Correction Collection:");
      (void) LogMagickEvent(TransformEvent,GetMagickModule(),
        "  color_correction.red.slope: %g",color_correction.red.slope);
      (void) LogMagickEvent(TransformEvent,GetMagickModule(),
        "  color_correction.red.offset: %g",color_correction.red.offset);
      (void) LogMagickEvent(TransformEvent,GetMagickModule(),
        "  color_correction.red.power: %g",color_correction.red.power);
      (void) LogMagickEvent(TransformEvent,GetMagickModule(),
        "  color_correction.green.slope: %g",color_correction.green.slope);
      (void) LogMagickEvent(TransformEvent,GetMagickModule(),
        "  color_correction.green.offset: %g",color_correction.green.offset);
      (void) LogMagickEvent(TransformEvent,GetMagickModule(),
        "  color_correction.green.power: %g",color_correction.green.power);
      (void) LogMagickEvent(TransformEvent,GetMagickModule(),
        "  color_correction.blue.slope: %g",color_correction.blue.slope);
      (void) LogMagickEvent(TransformEvent,GetMagickModule(),
        "  color_correction.blue.offset: %g",color_correction.blue.offset);
      (void) LogMagickEvent(TransformEvent,GetMagickModule(),
        "  color_correction.blue.power: %g",color_correction.blue.power);
      (void) LogMagickEvent(TransformEvent,GetMagickModule(),
        "  color_correction.saturation: %g",color_correction.saturation);
    }
  cdl_map=(PixelPacket *) AcquireQuantumMemory(MaxMap+1UL,sizeof(*cdl_map));
  if (cdl_map == (PixelPacket *) NULL)
    ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
      image->filename);
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4)
#endif
  for (i=0; i <= (ssize_t) MaxMap; i++)
  {
    cdl_map[i].red=ClampToQuantum((MagickRealType) ScaleMapToQuantum((
      MagickRealType) (MaxMap*(pow(color_correction.red.slope*i/MaxMap+
      color_correction.red.offset,color_correction.red.power)))));
    cdl_map[i].green=ClampToQuantum((MagickRealType) ScaleMapToQuantum((
      MagickRealType) (MaxMap*(pow(color_correction.green.slope*i/MaxMap+
      color_correction.green.offset,color_correction.green.power)))));
    cdl_map[i].blue=ClampToQuantum((MagickRealType) ScaleMapToQuantum((
      MagickRealType) (MaxMap*(pow(color_correction.blue.slope*i/MaxMap+
      color_correction.blue.offset,color_correction.blue.power)))));
  }
  if (image->storage_class == PseudoClass)
    {
      /*
        Apply transfer function to colormap.
      */
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
      for (i=0; i < (ssize_t) image->colors; i++)
      {
        double
          luma;

        luma=0.2126*image->colormap[i].red+0.7152*image->colormap[i].green+
          0.0722*image->colormap[i].blue;
        image->colormap[i].red=ClampToQuantum(luma+color_correction.saturation*
          cdl_map[ScaleQuantumToMap(image->colormap[i].red)].red-luma);
        image->colormap[i].green=ClampToQuantum(luma+
          color_correction.saturation*cdl_map[ScaleQuantumToMap(
          image->colormap[i].green)].green-luma);
        image->colormap[i].blue=ClampToQuantum(luma+color_correction.saturation*
          cdl_map[ScaleQuantumToMap(image->colormap[i].blue)].blue-luma);
      }
    }
  /*
    Apply transfer function to image.
  */
  status=MagickTrue;
  progress=0;
  exception=(&image->exception);
  image_view=AcquireCacheView(image);
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    double
      luma;

    register PixelPacket
      *restrict q;

    register ssize_t
      x;

    if (status == MagickFalse)
      continue;
    q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
    if (q == (PixelPacket *) NULL)
      {
        status=MagickFalse;
        continue;
      }
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      luma=0.2126*q->red+0.7152*q->green+0.0722*q->blue;
      q->red=ClampToQuantum(luma+color_correction.saturation*
        (cdl_map[ScaleQuantumToMap(q->red)].red-luma));
      q->green=ClampToQuantum(luma+color_correction.saturation*
        (cdl_map[ScaleQuantumToMap(q->green)].green-luma));
      q->blue=ClampToQuantum(luma+color_correction.saturation*
        (cdl_map[ScaleQuantumToMap(q->blue)].blue-luma));
      q++;
    }
    if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
      status=MagickFalse;
    if (image->progress_monitor != (MagickProgressMonitor) NULL)
      {
        MagickBooleanType
          proceed;

#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp critical (MagickCore_ColorDecisionListImageChannel)
#endif
        proceed=SetImageProgress(image,ColorDecisionListCorrectImageTag,
          progress++,image->rows);
        if (proceed == MagickFalse)
          status=MagickFalse;
      }
  }
  image_view=DestroyCacheView(image_view);
  cdl_map=(PixelPacket *) RelinquishMagickMemory(cdl_map);
  return(status);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%     C l u t I m a g e                                                       %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  ClutImage() replaces each color value in the given image, by using it as an
%  index to lookup a replacement color value in a Color Look UP Table in the
%  form of an image.  The values are extracted along a diagonal of the CLUT
%  image so either a horizontal or vertial gradient image can be used.
%
%  Typically this is used to either re-color a gray-scale image according to a
%  color gradient in the CLUT image, or to perform a freeform histogram
%  (level) adjustment according to the (typically gray-scale) gradient in the
%  CLUT image.
%
%  When the 'channel' mask includes the matte/alpha transparency channel but
%  one image has no such channel it is assumed that that image is a simple
%  gray-scale image that will effect the alpha channel values, either for
%  gray-scale coloring (with transparent or semi-transparent colors), or
%  a histogram adjustment of existing alpha channel values.   If both images
%  have matte channels, direct and normal indexing is applied, which is rarely
%  used.
%
%  The format of the ClutImage method is:
%
%      MagickBooleanType ClutImage(Image *image,Image *clut_image)
%      MagickBooleanType ClutImageChannel(Image *image,
%        const ChannelType channel,Image *clut_image)
%
%  A description of each parameter follows:
%
%    o image: the image, which is replaced by indexed CLUT values
%
%    o clut_image: the color lookup table image for replacement color values.
%
%    o channel: the channel.
%
*/

MagickExport MagickBooleanType ClutImage(Image *image,const Image *clut_image)
{
  return(ClutImageChannel(image,DefaultChannels,clut_image));
}

MagickExport MagickBooleanType ClutImageChannel(Image *image,
  const ChannelType channel,const Image *clut_image)
{
#define ClutImageTag  "Clut/Image"

  CacheView
    *clut_view,
    *image_view;

  ExceptionInfo
    *exception;

  MagickBooleanType
    status;

  MagickOffsetType
    progress;

  MagickPixelPacket
    *clut_map;

  register ssize_t
    i;

  ssize_t
    adjust,
    y;

  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  assert(clut_image != (Image *) NULL);
  assert(clut_image->signature == MagickSignature);
  if (SetImageStorageClass(image,DirectClass) == MagickFalse)
    return(MagickFalse);
  clut_map=(MagickPixelPacket *) AcquireQuantumMemory(MaxMap+1UL,
    sizeof(*clut_map));
  if (clut_map == (MagickPixelPacket *) NULL)
    ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
      image->filename);
  /*
    Clut image.
  */
  status=MagickTrue;
  progress=0;
  adjust=(ssize_t) (clut_image->interpolate == IntegerInterpolatePixel ? 0 : 1);
  exception=(&image->exception);
  clut_view=AcquireCacheView(clut_image);
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4)
#endif
  for (i=0; i <= (ssize_t) MaxMap; i++)
  {
    GetMagickPixelPacket(clut_image,clut_map+i);
    (void) InterpolateMagickPixelPacket(clut_image,clut_view,
      UndefinedInterpolatePixel,QuantumScale*i*(clut_image->columns-adjust),
      QuantumScale*i*(clut_image->rows-adjust),clut_map+i,exception);
  }
  clut_view=DestroyCacheView(clut_view);
  image_view=AcquireCacheView(image);
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    MagickPixelPacket
      pixel;

    register IndexPacket
      *restrict indexes;

    register PixelPacket
      *restrict q;

    register ssize_t
      x;

    if (status == MagickFalse)
      continue;
    q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
    if (q == (PixelPacket *) NULL)
      {
        status=MagickFalse;
        continue;
      }
    indexes=GetCacheViewAuthenticIndexQueue(image_view);
    GetMagickPixelPacket(image,&pixel);
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      SetMagickPixelPacket(image,q,indexes+x,&pixel);
      if ((channel & RedChannel) != 0)
        SetRedPixelComponent(q,ClampRedPixelComponent(clut_map+
          ScaleQuantumToMap(q->red)));
      if ((channel & GreenChannel) != 0)
        SetGreenPixelComponent(q,ClampGreenPixelComponent(clut_map+
          ScaleQuantumToMap(q->green)));
      if ((channel & BlueChannel) != 0)
        SetBluePixelComponent(q,ClampBluePixelComponent(clut_map+
          ScaleQuantumToMap(q->blue)));
      if ((channel & OpacityChannel) != 0)
        {
          if (clut_image->matte == MagickFalse)
            q->opacity=(Quantum) (QuantumRange-MagickPixelIntensityToQuantum(
              clut_map+ScaleQuantumToMap((Quantum) GetAlphaPixelComponent(q))));
          else
            if (image->matte == MagickFalse)
              SetOpacityPixelComponent(q,ClampOpacityPixelComponent(clut_map+
                ScaleQuantumToMap((Quantum) MagickPixelIntensity(&pixel))));
            else
              SetOpacityPixelComponent(q,ClampOpacityPixelComponent(
                clut_map+ScaleQuantumToMap(q->opacity)));
        }
      if (((channel & IndexChannel) != 0) &&
          (image->colorspace == CMYKColorspace))
        indexes[x]=ClampToQuantum((clut_map+(ssize_t) indexes[x])->index);
      q++;
    }
    if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
      status=MagickFalse;
    if (image->progress_monitor != (MagickProgressMonitor) NULL)
      {
        MagickBooleanType
          proceed;

#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp critical (MagickCore_ClutImageChannel)
#endif
        proceed=SetImageProgress(image,ClutImageTag,progress++,image->rows);
        if (proceed == MagickFalse)
          status=MagickFalse;
      }
  }
  image_view=DestroyCacheView(image_view);
  clut_map=(MagickPixelPacket *) RelinquishMagickMemory(clut_map);
  if ((clut_image->matte != MagickFalse) && ((channel & OpacityChannel) != 0))
    (void) SetImageAlphaChannel(image,ActivateAlphaChannel);
  return(status);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%     C o n t r a s t I m a g e                                               %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  ContrastImage() enhances the intensity differences between the lighter and
%  darker elements of the image.  Set sharpen to a MagickTrue to increase the
%  image contrast otherwise the contrast is reduced.
%
%  The format of the ContrastImage method is:
%
%      MagickBooleanType ContrastImage(Image *image,
%        const MagickBooleanType sharpen)
%
%  A description of each parameter follows:
%
%    o image: the image.
%
%    o sharpen: Increase or decrease image contrast.
%
*/

static void Contrast(const int sign,Quantum *red,Quantum *green,Quantum *blue)
{
  double
    brightness,
    hue,
    saturation;

  /*
    Enhance contrast: dark color become darker, light color become lighter.
  */
  assert(red != (Quantum *) NULL);
  assert(green != (Quantum *) NULL);
  assert(blue != (Quantum *) NULL);
  hue=0.0;
  saturation=0.0;
  brightness=0.0;
  ConvertRGBToHSB(*red,*green,*blue,&hue,&saturation,&brightness);
  brightness+=0.5*sign*(0.5*(sin((double) (MagickPI*(brightness-0.5)))+1.0)-
    brightness);
  if (brightness > 1.0)
    brightness=1.0;
  else
    if (brightness < 0.0)
      brightness=0.0;
  ConvertHSBToRGB(hue,saturation,brightness,red,green,blue);
}

MagickExport MagickBooleanType ContrastImage(Image *image,
  const MagickBooleanType sharpen)
{
#define ContrastImageTag  "Contrast/Image"

  CacheView
    *image_view;

  ExceptionInfo
    *exception;

  int
    sign;

  MagickBooleanType
    status;

  MagickOffsetType
    progress;

  register ssize_t
    i;

  ssize_t
    y;

  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  sign=sharpen != MagickFalse ? 1 : -1;
  if (image->storage_class == PseudoClass)
    {
      /*
        Contrast enhance colormap.
      */
      for (i=0; i < (ssize_t) image->colors; i++)
        Contrast(sign,&image->colormap[i].red,&image->colormap[i].green,
          &image->colormap[i].blue);
    }
  /*
    Contrast enhance image.
  */
  status=MagickTrue;
  progress=0;
  exception=(&image->exception);
  image_view=AcquireCacheView(image);
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    register PixelPacket
      *restrict q;

    register ssize_t
      x;

    if (status == MagickFalse)
      continue;
    q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
    if (q == (PixelPacket *) NULL)
      {
        status=MagickFalse;
        continue;
      }
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      Contrast(sign,&q->red,&q->green,&q->blue);
      q++;
    }
    if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
      status=MagickFalse;
    if (image->progress_monitor != (MagickProgressMonitor) NULL)
      {
        MagickBooleanType
          proceed;

#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp critical (MagickCore_ContrastImage)
#endif
        proceed=SetImageProgress(image,ContrastImageTag,progress++,image->rows);
        if (proceed == MagickFalse)
          status=MagickFalse;
      }
  }
  image_view=DestroyCacheView(image_view);
  return(status);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%     C o n t r a s t S t r e t c h I m a g e                                 %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  The ContrastStretchImage() is a simple image enhancement technique that
%  attempts to improve the contrast in an image by `stretching' the range of
%  intensity values it contains to span a desired range of values. It differs
%  from the more sophisticated histogram equalization in that it can only
%  apply %  a linear scaling function to the image pixel values.  As a result
%  the `enhancement' is less harsh.
%
%  The format of the ContrastStretchImage method is:
%
%      MagickBooleanType ContrastStretchImage(Image *image,
%        const char *levels)
%      MagickBooleanType ContrastStretchImageChannel(Image *image,
%        const size_t channel,const double black_point,
%        const double white_point)
%
%  A description of each parameter follows:
%
%    o image: the image.
%
%    o channel: the channel.
%
%    o black_point: the black point.
%
%    o white_point: the white point.
%
%    o levels: Specify the levels where the black and white points have the
%      range of 0 to number-of-pixels (e.g. 1%, 10x90%, etc.).
%
*/

MagickExport MagickBooleanType ContrastStretchImage(Image *image,
  const char *levels)
{
  double
    black_point,
    white_point;

  GeometryInfo
    geometry_info;

  MagickBooleanType
    status;

  MagickStatusType
    flags;

  /*
    Parse levels.
  */
  if (levels == (char *) NULL)
    return(MagickFalse);
  flags=ParseGeometry(levels,&geometry_info);
  black_point=geometry_info.rho;
  white_point=(double) image->columns*image->rows;
  if ((flags & SigmaValue) != 0)
    white_point=geometry_info.sigma;
  if ((flags & PercentValue) != 0)
    {
      black_point*=(double) QuantumRange/100.0;
      white_point*=(double) QuantumRange/100.0;
    }
  if ((flags & SigmaValue) == 0)
    white_point=(double) image->columns*image->rows-black_point;
  status=ContrastStretchImageChannel(image,DefaultChannels,black_point,
    white_point);
  return(status);
}

MagickExport MagickBooleanType ContrastStretchImageChannel(Image *image,
  const ChannelType channel,const double black_point,const double white_point)
{
#define MaxRange(color)  ((MagickRealType) ScaleQuantumToMap((Quantum) (color)))
#define ContrastStretchImageTag  "ContrastStretch/Image"

  CacheView
    *image_view;

  double
    intensity;

  ExceptionInfo
    *exception;

  MagickBooleanType
    status;

  MagickOffsetType
    progress;

  MagickPixelPacket
    black,
    *histogram,
    *stretch_map,
    white;

  register ssize_t
    i;

  ssize_t
    y;

  /*
    Allocate histogram and stretch map.
  */
  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  histogram=(MagickPixelPacket *) AcquireQuantumMemory(MaxMap+1UL,
    sizeof(*histogram));
  stretch_map=(MagickPixelPacket *) AcquireQuantumMemory(MaxMap+1UL,
    sizeof(*stretch_map));
  if ((histogram == (MagickPixelPacket *) NULL) ||
      (stretch_map == (MagickPixelPacket *) NULL))
    ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
      image->filename);
  /*
    Form histogram.
  */
  status=MagickTrue;
  exception=(&image->exception);
  (void) ResetMagickMemory(histogram,0,(MaxMap+1)*sizeof(*histogram));
  image_view=AcquireCacheView(image);
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    register const PixelPacket
      *restrict p;

    register IndexPacket
      *restrict indexes;

    register ssize_t
      x;

    if (status == MagickFalse)
      continue;
    p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
    if (p == (const PixelPacket *) NULL)
      {
        status=MagickFalse;
        continue;
      }
    indexes=GetCacheViewAuthenticIndexQueue(image_view);
    if (channel == DefaultChannels)
      for (x=0; x < (ssize_t) image->columns; x++)
      {
        Quantum
          intensity;

        intensity=PixelIntensityToQuantum(p);
        histogram[ScaleQuantumToMap(intensity)].red++;
        histogram[ScaleQuantumToMap(intensity)].green++;
        histogram[ScaleQuantumToMap(intensity)].blue++;
        histogram[ScaleQuantumToMap(intensity)].index++;
        p++;
      }
    else
      for (x=0; x < (ssize_t) image->columns; x++)
      {
        if ((channel & RedChannel) != 0)
          histogram[ScaleQuantumToMap(GetRedPixelComponent(p))].red++;
        if ((channel & GreenChannel) != 0)
          histogram[ScaleQuantumToMap(GetGreenPixelComponent(p))].green++;
        if ((channel & BlueChannel) != 0)
          histogram[ScaleQuantumToMap(GetBluePixelComponent(p))].blue++;
        if ((channel & OpacityChannel) != 0)
          histogram[ScaleQuantumToMap(GetOpacityPixelComponent(p))].opacity++;
        if (((channel & IndexChannel) != 0) &&
            (image->colorspace == CMYKColorspace))
          histogram[ScaleQuantumToMap(indexes[x])].index++;
        p++;
      }
  }
  /*
    Find the histogram boundaries by locating the black/white levels.
  */
  black.red=0.0;
  white.red=MaxRange(QuantumRange);
  if ((channel & RedChannel) != 0)
    {
      intensity=0.0;
      for (i=0; i <= (ssize_t) MaxMap; i++)
      {
        intensity+=histogram[i].red;
        if (intensity > black_point)
          break;
      }
      black.red=(MagickRealType) i;
      intensity=0.0;
      for (i=(ssize_t) MaxMap; i != 0; i--)
      {
        intensity+=histogram[i].red;
        if (intensity > ((double) image->columns*image->rows-white_point))
          break;
      }
      white.red=(MagickRealType) i;
    }
  black.green=0.0;
  white.green=MaxRange(QuantumRange);
  if ((channel & GreenChannel) != 0)
    {
      intensity=0.0;
      for (i=0; i <= (ssize_t) MaxMap; i++)
      {
        intensity+=histogram[i].green;
        if (intensity > black_point)
          break;
      }
      black.green=(MagickRealType) i;
      intensity=0.0;
      for (i=(ssize_t) MaxMap; i != 0; i--)
      {
        intensity+=histogram[i].green;
        if (intensity > ((double) image->columns*image->rows-white_point))
          break;
      }
      white.green=(MagickRealType) i;
    }
  black.blue=0.0;
  white.blue=MaxRange(QuantumRange);
  if ((channel & BlueChannel) != 0)
    {
      intensity=0.0;
      for (i=0; i <= (ssize_t) MaxMap; i++)
      {
        intensity+=histogram[i].blue;
        if (intensity > black_point)
          break;
      }
      black.blue=(MagickRealType) i;
      intensity=0.0;
      for (i=(ssize_t) MaxMap; i != 0; i--)
      {
        intensity+=histogram[i].blue;
        if (intensity > ((double) image->columns*image->rows-white_point))
          break;
      }
      white.blue=(MagickRealType) i;
    }
  black.opacity=0.0;
  white.opacity=MaxRange(QuantumRange);
  if ((channel & OpacityChannel) != 0)
    {
      intensity=0.0;
      for (i=0; i <= (ssize_t) MaxMap; i++)
      {
        intensity+=histogram[i].opacity;
        if (intensity > black_point)
          break;
      }
      black.opacity=(MagickRealType) i;
      intensity=0.0;
      for (i=(ssize_t) MaxMap; i != 0; i--)
      {
        intensity+=histogram[i].opacity;
        if (intensity > ((double) image->columns*image->rows-white_point))
          break;
      }
      white.opacity=(MagickRealType) i;
    }
  black.index=0.0;
  white.index=MaxRange(QuantumRange);
  if (((channel & IndexChannel) != 0) && (image->colorspace == CMYKColorspace))
    {
      intensity=0.0;
      for (i=0; i <= (ssize_t) MaxMap; i++)
      {
        intensity+=histogram[i].index;
        if (intensity > black_point)
          break;
      }
      black.index=(MagickRealType) i;
      intensity=0.0;
      for (i=(ssize_t) MaxMap; i != 0; i--)
      {
        intensity+=histogram[i].index;
        if (intensity > ((double) image->columns*image->rows-white_point))
          break;
      }
      white.index=(MagickRealType) i;
    }
  histogram=(MagickPixelPacket *) RelinquishMagickMemory(histogram);
  /*
    Stretch the histogram to create the stretched image mapping.
  */
  (void) ResetMagickMemory(stretch_map,0,(MaxMap+1)*sizeof(*stretch_map));
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
  for (i=0; i <= (ssize_t) MaxMap; i++)
  {
    if ((channel & RedChannel) != 0)
      {
        if (i < (ssize_t) black.red)
          stretch_map[i].red=0.0;
        else
          if (i > (ssize_t) white.red)
            stretch_map[i].red=(MagickRealType) QuantumRange;
          else
            if (black.red != white.red)
              stretch_map[i].red=(MagickRealType) ScaleMapToQuantum(
                (MagickRealType) (MaxMap*(i-black.red)/(white.red-black.red)));
      }
    if ((channel & GreenChannel) != 0)
      {
        if (i < (ssize_t) black.green)
          stretch_map[i].green=0.0;
        else
          if (i > (ssize_t) white.green)
            stretch_map[i].green=(MagickRealType) QuantumRange;
          else
            if (black.green != white.green)
              stretch_map[i].green=(MagickRealType) ScaleMapToQuantum(
                (MagickRealType) (MaxMap*(i-black.green)/(white.green-
                black.green)));
      }
    if ((channel & BlueChannel) != 0)
      {
        if (i < (ssize_t) black.blue)
          stretch_map[i].blue=0.0;
        else
          if (i > (ssize_t) white.blue)
            stretch_map[i].blue=(MagickRealType) QuantumRange;
          else
            if (black.blue != white.blue)
              stretch_map[i].blue=(MagickRealType) ScaleMapToQuantum(
                (MagickRealType) (MaxMap*(i-black.blue)/(white.blue-
                black.blue)));
      }
    if ((channel & OpacityChannel) != 0)
      {
        if (i < (ssize_t) black.opacity)
          stretch_map[i].opacity=0.0;
        else
          if (i > (ssize_t) white.opacity)
            stretch_map[i].opacity=(MagickRealType) QuantumRange;
          else
            if (black.opacity != white.opacity)
              stretch_map[i].opacity=(MagickRealType) ScaleMapToQuantum(
                (MagickRealType) (MaxMap*(i-black.opacity)/(white.opacity-
                black.opacity)));
      }
    if (((channel & IndexChannel) != 0) &&
        (image->colorspace == CMYKColorspace))
      {
        if (i < (ssize_t) black.index)
          stretch_map[i].index=0.0;
        else
          if (i > (ssize_t) white.index)
            stretch_map[i].index=(MagickRealType) QuantumRange;
          else
            if (black.index != white.index)
              stretch_map[i].index=(MagickRealType) ScaleMapToQuantum(
                (MagickRealType) (MaxMap*(i-black.index)/(white.index-
                black.index)));
      }
  }
  /*
    Stretch the image.
  */
  if (((channel & OpacityChannel) != 0) || (((channel & IndexChannel) != 0) &&
      (image->colorspace == CMYKColorspace)))
    image->storage_class=DirectClass;
  if (image->storage_class == PseudoClass)
    {
      /*
        Stretch colormap.
      */
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
      for (i=0; i < (ssize_t) image->colors; i++)
      {
        if ((channel & RedChannel) != 0)
          {
            if (black.red != white.red)
              image->colormap[i].red=ClampToQuantum(stretch_map[
                ScaleQuantumToMap(image->colormap[i].red)].red);
          }
        if ((channel & GreenChannel) != 0)
          {
            if (black.green != white.green)
              image->colormap[i].green=ClampToQuantum(stretch_map[
                ScaleQuantumToMap(image->colormap[i].green)].green);
          }
        if ((channel & BlueChannel) != 0)
          {
            if (black.blue != white.blue)
              image->colormap[i].blue=ClampToQuantum(stretch_map[
                ScaleQuantumToMap(image->colormap[i].blue)].blue);
          }
        if ((channel & OpacityChannel) != 0)
          {
            if (black.opacity != white.opacity)
              image->colormap[i].opacity=ClampToQuantum(stretch_map[
                ScaleQuantumToMap(image->colormap[i].opacity)].opacity);
          }
      }
    }
  /*
    Stretch image.
  */
  status=MagickTrue;
  progress=0;
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    register IndexPacket
      *restrict indexes;

    register PixelPacket
      *restrict q;

    register ssize_t
      x;

    if (status == MagickFalse)
      continue;
    q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
    if (q == (PixelPacket *) NULL)
      {
        status=MagickFalse;
        continue;
      }
    indexes=GetCacheViewAuthenticIndexQueue(image_view);
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      if ((channel & RedChannel) != 0)
        {
          if (black.red != white.red)
            q->red=ClampToQuantum(stretch_map[ScaleQuantumToMap(q->red)].red);
        }
      if ((channel & GreenChannel) != 0)
        {
          if (black.green != white.green)
            q->green=ClampToQuantum(stretch_map[ScaleQuantumToMap(
              q->green)].green);
        }
      if ((channel & BlueChannel) != 0)
        {
          if (black.blue != white.blue)
            q->blue=ClampToQuantum(stretch_map[ScaleQuantumToMap(
              q->blue)].blue);
        }
      if ((channel & OpacityChannel) != 0)
        {
          if (black.opacity != white.opacity)
            q->opacity=ClampToQuantum(stretch_map[ScaleQuantumToMap(
              q->opacity)].opacity);
        }
      if (((channel & IndexChannel) != 0) &&
          (image->colorspace == CMYKColorspace))
        {
          if (black.index != white.index)
            indexes[x]=(IndexPacket) ClampToQuantum(stretch_map[
              ScaleQuantumToMap(indexes[x])].index);
        }
      q++;
    }
    if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
      status=MagickFalse;
    if (image->progress_monitor != (MagickProgressMonitor) NULL)
      {
        MagickBooleanType
          proceed;

#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp critical (MagickCore_ContrastStretchImageChannel)
#endif
        proceed=SetImageProgress(image,ContrastStretchImageTag,progress++,
          image->rows);
        if (proceed == MagickFalse)
          status=MagickFalse;
      }
  }
  image_view=DestroyCacheView(image_view);
  stretch_map=(MagickPixelPacket *) RelinquishMagickMemory(stretch_map);
  return(status);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%     E n h a n c e I m a g e                                                 %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  EnhanceImage() applies a digital filter that improves the quality of a
%  noisy image.
%
%  The format of the EnhanceImage method is:
%
%      Image *EnhanceImage(const Image *image,ExceptionInfo *exception)
%
%  A description of each parameter follows:
%
%    o image: the image.
%
%    o exception: return any errors or warnings in this structure.
%
*/
MagickExport Image *EnhanceImage(const Image *image,ExceptionInfo *exception)
{
#define Enhance(weight) \
  mean=((MagickRealType) r->red+pixel.red)/2; \
  distance=(MagickRealType) r->red-(MagickRealType) pixel.red; \
  distance_squared=QuantumScale*(2.0*((MagickRealType) QuantumRange+1.0)+ \
     mean)*distance*distance; \
  mean=((MagickRealType) r->green+pixel.green)/2; \
  distance=(MagickRealType) r->green-(MagickRealType) pixel.green; \
  distance_squared+=4.0*distance*distance; \
  mean=((MagickRealType) r->blue+pixel.blue)/2; \
  distance=(MagickRealType) r->blue-(MagickRealType) pixel.blue; \
  distance_squared+=QuantumScale*(3.0*((MagickRealType) \
    QuantumRange+1.0)-1.0-mean)*distance*distance; \
  mean=((MagickRealType) r->opacity+pixel.opacity)/2; \
  distance=(MagickRealType) r->opacity-(MagickRealType) pixel.opacity; \
  distance_squared+=QuantumScale*(3.0*((MagickRealType) \
    QuantumRange+1.0)-1.0-mean)*distance*distance; \
  if (distance_squared < ((MagickRealType) QuantumRange*(MagickRealType) \
      QuantumRange/25.0f)) \
    { \
      aggregate.red+=(weight)*r->red; \
      aggregate.green+=(weight)*r->green; \
      aggregate.blue+=(weight)*r->blue; \
      aggregate.opacity+=(weight)*r->opacity; \
      total_weight+=(weight); \
    } \
  r++;
#define EnhanceImageTag  "Enhance/Image"

  CacheView
    *enhance_view,
    *image_view;

  Image
    *enhance_image;

  MagickBooleanType
    status;

  MagickOffsetType
    progress;

  MagickPixelPacket
    zero;

  ssize_t
    y;

  /*
    Initialize enhanced image attributes.
  */
  assert(image != (const Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  assert(exception != (ExceptionInfo *) NULL);
  assert(exception->signature == MagickSignature);
  if ((image->columns < 5) || (image->rows < 5))
    return((Image *) NULL);
  enhance_image=CloneImage(image,image->columns,image->rows,MagickTrue,
    exception);
  if (enhance_image == (Image *) NULL)
    return((Image *) NULL);
  if (SetImageStorageClass(enhance_image,DirectClass) == MagickFalse)
    {
      InheritException(exception,&enhance_image->exception);
      enhance_image=DestroyImage(enhance_image);
      return((Image *) NULL);
    }
  /*
    Enhance image.
  */
  status=MagickTrue;
  progress=0;
  (void) ResetMagickMemory(&zero,0,sizeof(zero));
  image_view=AcquireCacheView(image);
  enhance_view=AcquireCacheView(enhance_image);
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    register const PixelPacket
      *restrict p;

    register PixelPacket
      *restrict q;

    register ssize_t
      x;

    /*
      Read another scan line.
    */
    if (status == MagickFalse)
      continue;
    p=GetCacheViewVirtualPixels(image_view,-2,y-2,image->columns+4,5,exception);
    q=QueueCacheViewAuthenticPixels(enhance_view,0,y,enhance_image->columns,1,
      exception);
    if ((p == (const PixelPacket *) NULL) || (q == (PixelPacket *) NULL))
      {
        status=MagickFalse;
        continue;
      }
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      MagickPixelPacket
        aggregate;

      MagickRealType
        distance,
        distance_squared,
        mean,
        total_weight;

      PixelPacket
        pixel;

      register const PixelPacket
        *restrict r;

      /*
        Compute weighted average of target pixel color components.
      */
      aggregate=zero;
      total_weight=0.0;
      r=p+2*(image->columns+4)+2;
      pixel=(*r);
      r=p;
      Enhance(5.0); Enhance(8.0); Enhance(10.0); Enhance(8.0); Enhance(5.0);
      r=p+(image->columns+4);
      Enhance(8.0); Enhance(20.0); Enhance(40.0); Enhance(20.0); Enhance(8.0);
      r=p+2*(image->columns+4);
      Enhance(10.0); Enhance(40.0); Enhance(80.0); Enhance(40.0); Enhance(10.0);
      r=p+3*(image->columns+4);
      Enhance(8.0); Enhance(20.0); Enhance(40.0); Enhance(20.0); Enhance(8.0);
      r=p+4*(image->columns+4);
      Enhance(5.0); Enhance(8.0); Enhance(10.0); Enhance(8.0); Enhance(5.0);
      q->red=(Quantum) ((aggregate.red+(total_weight/2)-1)/total_weight);
      q->green=(Quantum) ((aggregate.green+(total_weight/2)-1)/total_weight);
      q->blue=(Quantum) ((aggregate.blue+(total_weight/2)-1)/total_weight);
      q->opacity=(Quantum) ((aggregate.opacity+(total_weight/2)-1)/
        total_weight);
      p++;
      q++;
    }
    if (SyncCacheViewAuthenticPixels(enhance_view,exception) == MagickFalse)
      status=MagickFalse;
    if (image->progress_monitor != (MagickProgressMonitor) NULL)
      {
        MagickBooleanType
          proceed;

#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp critical (MagickCore_EnhanceImage)
#endif
        proceed=SetImageProgress(image,EnhanceImageTag,progress++,image->rows);
        if (proceed == MagickFalse)
          status=MagickFalse;
      }
  }
  enhance_view=DestroyCacheView(enhance_view);
  image_view=DestroyCacheView(image_view);
  return(enhance_image);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%     E q u a l i z e I m a g e                                               %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  EqualizeImage() applies a histogram equalization to the image.
%
%  The format of the EqualizeImage method is:
%
%      MagickBooleanType EqualizeImage(Image *image)
%      MagickBooleanType EqualizeImageChannel(Image *image,
%        const ChannelType channel)
%
%  A description of each parameter follows:
%
%    o image: the image.
%
%    o channel: the channel.
%
*/

MagickExport MagickBooleanType EqualizeImage(Image *image)
{
  return(EqualizeImageChannel(image,DefaultChannels));
}

MagickExport MagickBooleanType EqualizeImageChannel(Image *image,
  const ChannelType channel)
{
#define EqualizeImageTag  "Equalize/Image"

  CacheView
    *image_view;

  ExceptionInfo
    *exception;

  MagickBooleanType
    status;

  MagickOffsetType
    progress;

  MagickPixelPacket
    black,
    *equalize_map,
    *histogram,
    intensity,
    *map,
    white;

  register ssize_t
    i;

  ssize_t
    y;

  /*
    Allocate and initialize histogram arrays.
  */
  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  equalize_map=(MagickPixelPacket *) AcquireQuantumMemory(MaxMap+1UL,
    sizeof(*equalize_map));
  histogram=(MagickPixelPacket *) AcquireQuantumMemory(MaxMap+1UL,
    sizeof(*histogram));
  map=(MagickPixelPacket *) AcquireQuantumMemory(MaxMap+1UL,sizeof(*map));
  if ((equalize_map == (MagickPixelPacket *) NULL) ||
      (histogram == (MagickPixelPacket *) NULL) ||
      (map == (MagickPixelPacket *) NULL))
    {
      if (map != (MagickPixelPacket *) NULL)
        map=(MagickPixelPacket *) RelinquishMagickMemory(map);
      if (histogram != (MagickPixelPacket *) NULL)
        histogram=(MagickPixelPacket *) RelinquishMagickMemory(histogram);
      if (equalize_map != (MagickPixelPacket *) NULL)
        equalize_map=(MagickPixelPacket *) RelinquishMagickMemory(equalize_map);
      ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
        image->filename);
    }
  /*
    Form histogram.
  */
  (void) ResetMagickMemory(histogram,0,(MaxMap+1)*sizeof(*histogram));
  exception=(&image->exception);
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    register const IndexPacket
      *restrict indexes;

    register const PixelPacket
      *restrict p;

    register ssize_t
      x;

    p=GetVirtualPixels(image,0,y,image->columns,1,exception);
    if (p == (const PixelPacket *) NULL)
      break;
    indexes=GetVirtualIndexQueue(image);
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      if ((channel & RedChannel) != 0)
        histogram[ScaleQuantumToMap(GetRedPixelComponent(p))].red++;
      if ((channel & GreenChannel) != 0)
        histogram[ScaleQuantumToMap(GetGreenPixelComponent(p))].green++;
      if ((channel & BlueChannel) != 0)
        histogram[ScaleQuantumToMap(GetBluePixelComponent(p))].blue++;
      if ((channel & OpacityChannel) != 0)
        histogram[ScaleQuantumToMap(GetOpacityPixelComponent(p))].opacity++;
      if (((channel & IndexChannel) != 0) &&
          (image->colorspace == CMYKColorspace))
        histogram[ScaleQuantumToMap(indexes[x])].index++;
      p++;
    }
  }
  /*
    Integrate the histogram to get the equalization map.
  */
  (void) ResetMagickMemory(&intensity,0,sizeof(intensity));
  for (i=0; i <= (ssize_t) MaxMap; i++)
  {
    if ((channel & RedChannel) != 0)
      intensity.red+=histogram[i].red;
    if ((channel & GreenChannel) != 0)
      intensity.green+=histogram[i].green;
    if ((channel & BlueChannel) != 0)
      intensity.blue+=histogram[i].blue;
    if ((channel & OpacityChannel) != 0)
      intensity.opacity+=histogram[i].opacity;
    if (((channel & IndexChannel) != 0) &&
        (image->colorspace == CMYKColorspace))
      intensity.index+=histogram[i].index;
    map[i]=intensity;
  }
  black=map[0];
  white=map[(int) MaxMap];
  (void) ResetMagickMemory(equalize_map,0,(MaxMap+1)*sizeof(*equalize_map));
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
  for (i=0; i <= (ssize_t) MaxMap; i++)
  {
    if (((channel & RedChannel) != 0) && (white.red != black.red))
      equalize_map[i].red=(MagickRealType) ScaleMapToQuantum((MagickRealType)
        ((MaxMap*(map[i].red-black.red))/(white.red-black.red)));
    if (((channel & GreenChannel) != 0) && (white.green != black.green))
      equalize_map[i].green=(MagickRealType) ScaleMapToQuantum((MagickRealType)
        ((MaxMap*(map[i].green-black.green))/(white.green-black.green)));
    if (((channel & BlueChannel) != 0) && (white.blue != black.blue))
      equalize_map[i].blue=(MagickRealType) ScaleMapToQuantum((MagickRealType)
        ((MaxMap*(map[i].blue-black.blue))/(white.blue-black.blue)));
    if (((channel & OpacityChannel) != 0) && (white.opacity != black.opacity))
      equalize_map[i].opacity=(MagickRealType) ScaleMapToQuantum(
        (MagickRealType) ((MaxMap*(map[i].opacity-black.opacity))/
        (white.opacity-black.opacity)));
    if ((((channel & IndexChannel) != 0) &&
        (image->colorspace == CMYKColorspace)) &&
        (white.index != black.index))
      equalize_map[i].index=(MagickRealType) ScaleMapToQuantum((MagickRealType)
        ((MaxMap*(map[i].index-black.index))/(white.index-black.index)));
  }
  histogram=(MagickPixelPacket *) RelinquishMagickMemory(histogram);
  map=(MagickPixelPacket *) RelinquishMagickMemory(map);
  if (image->storage_class == PseudoClass)
    {
      /*
        Equalize colormap.
      */
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
      for (i=0; i < (ssize_t) image->colors; i++)
      {
        if (((channel & RedChannel) != 0) && (white.red != black.red))
          image->colormap[i].red=ClampToQuantum(equalize_map[
            ScaleQuantumToMap(image->colormap[i].red)].red);
        if (((channel & GreenChannel) != 0) && (white.green != black.green))
          image->colormap[i].green=ClampToQuantum(equalize_map[
            ScaleQuantumToMap(image->colormap[i].green)].green);
        if (((channel & BlueChannel) != 0) && (white.blue != black.blue))
          image->colormap[i].blue=ClampToQuantum(equalize_map[
            ScaleQuantumToMap(image->colormap[i].blue)].blue);
        if (((channel & OpacityChannel) != 0) &&
            (white.opacity != black.opacity))
          image->colormap[i].opacity=ClampToQuantum(equalize_map[
            ScaleQuantumToMap(image->colormap[i].opacity)].opacity);
      }
    }
  /*
    Equalize image.
  */
  status=MagickTrue;
  progress=0;
  exception=(&image->exception);
  image_view=AcquireCacheView(image);
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    register IndexPacket
      *restrict indexes;

    register PixelPacket
      *restrict q;

    register ssize_t
      x;

    if (status == MagickFalse)
      continue;
    q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
    if (q == (PixelPacket *) NULL)
      {
        status=MagickFalse;
        continue;
      }
    indexes=GetCacheViewAuthenticIndexQueue(image_view);
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      if (((channel & RedChannel) != 0) && (white.red != black.red))
        q->red=ClampToQuantum(equalize_map[ScaleQuantumToMap(q->red)].red);
      if (((channel & GreenChannel) != 0) && (white.green != black.green))
        q->green=ClampToQuantum(equalize_map[ScaleQuantumToMap(
          q->green)].green);
      if (((channel & BlueChannel) != 0) && (white.blue != black.blue))
        q->blue=ClampToQuantum(equalize_map[ScaleQuantumToMap(q->blue)].blue);
      if (((channel & OpacityChannel) != 0) && (white.opacity != black.opacity))
        q->opacity=ClampToQuantum(equalize_map[ScaleQuantumToMap(
          q->opacity)].opacity);
      if ((((channel & IndexChannel) != 0) &&
          (image->colorspace == CMYKColorspace)) &&
          (white.index != black.index))
        indexes[x]=ClampToQuantum(equalize_map[ScaleQuantumToMap(
          indexes[x])].index);
      q++;
    }
    if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
      status=MagickFalse;
    if (image->progress_monitor != (MagickProgressMonitor) NULL)
      {
        MagickBooleanType
          proceed;

#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp critical (MagickCore_EqualizeImageChannel)
#endif
        proceed=SetImageProgress(image,EqualizeImageTag,progress++,image->rows);
        if (proceed == MagickFalse)
          status=MagickFalse;
      }
  }
  image_view=DestroyCacheView(image_view);
  equalize_map=(MagickPixelPacket *) RelinquishMagickMemory(equalize_map);
  return(status);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%     G a m m a I m a g e                                                     %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  GammaImage() gamma-corrects a particular image channel.  The same
%  image viewed on different devices will have perceptual differences in the
%  way the image's intensities are represented on the screen.  Specify
%  individual gamma levels for the red, green, and blue channels, or adjust
%  all three with the gamma parameter.  Values typically range from 0.8 to 2.3.
%
%  You can also reduce the influence of a particular channel with a gamma
%  value of 0.
%
%  The format of the GammaImage method is:
%
%      MagickBooleanType GammaImage(Image *image,const char *level)
%      MagickBooleanType GammaImageChannel(Image *image,
%        const ChannelType channel,const double gamma)
%
%  A description of each parameter follows:
%
%    o image: the image.
%
%    o channel: the channel.
%
%    o level: the image gamma as a string (e.g. 1.6,1.2,1.0).
%
%    o gamma: the image gamma.
%
*/
MagickExport MagickBooleanType GammaImage(Image *image,const char *level)
{
  GeometryInfo
    geometry_info;

  MagickPixelPacket
    gamma;

  MagickStatusType
    flags,
    status;

  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  if (level == (char *) NULL)
    return(MagickFalse);
  flags=ParseGeometry(level,&geometry_info);
  gamma.red=geometry_info.rho;
  gamma.green=geometry_info.sigma;
  if ((flags & SigmaValue) == 0)
    gamma.green=gamma.red;
  gamma.blue=geometry_info.xi;
  if ((flags & XiValue) == 0)
    gamma.blue=gamma.red;
  if ((gamma.red == 1.0) && (gamma.green == 1.0) && (gamma.blue == 1.0))
    return(MagickTrue);
  if ((gamma.red == gamma.green) && (gamma.green == gamma.blue))
    status=GammaImageChannel(image,(const ChannelType) (RedChannel |
      GreenChannel | BlueChannel),(double) gamma.red);
  else
    {
      status=GammaImageChannel(image,RedChannel,(double) gamma.red);
      status|=GammaImageChannel(image,GreenChannel,(double) gamma.green);
      status|=GammaImageChannel(image,BlueChannel,(double) gamma.blue);
    }
  return(status != 0 ? MagickTrue : MagickFalse);
}

MagickExport MagickBooleanType GammaImageChannel(Image *image,
  const ChannelType channel,const double gamma)
{
#define GammaCorrectImageTag  "GammaCorrect/Image"

  CacheView
    *image_view;

  ExceptionInfo
    *exception;

  MagickBooleanType
    status;

  MagickOffsetType
    progress;

  Quantum
    *gamma_map;

  register ssize_t
    i;

  ssize_t
    y;

  /*
    Allocate and initialize gamma maps.
  */
  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  if (gamma == 1.0)
    return(MagickTrue);
  gamma_map=(Quantum *) AcquireQuantumMemory(MaxMap+1UL,sizeof(*gamma_map));
  if (gamma_map == (Quantum *) NULL)
    ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
      image->filename);
  (void) ResetMagickMemory(gamma_map,0,(MaxMap+1)*sizeof(*gamma_map));
  if (gamma != 0.0)
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4)
#endif
    for (i=0; i <= (ssize_t) MaxMap; i++)
      gamma_map[i]=ClampToQuantum((MagickRealType) ScaleMapToQuantum((
        MagickRealType) (MaxMap*pow((double) i/MaxMap,1.0/gamma))));
  if (image->storage_class == PseudoClass)
    {
      /*
        Gamma-correct colormap.
      */
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
      for (i=0; i < (ssize_t) image->colors; i++)
      {
        if ((channel & RedChannel) != 0)
          image->colormap[i].red=gamma_map[
            ScaleQuantumToMap(image->colormap[i].red)];
        if ((channel & GreenChannel) != 0)
          image->colormap[i].green=gamma_map[
            ScaleQuantumToMap(image->colormap[i].green)];
        if ((channel & BlueChannel) != 0)
          image->colormap[i].blue=gamma_map[
            ScaleQuantumToMap(image->colormap[i].blue)];
        if ((channel & OpacityChannel) != 0)
          {
            if (image->matte == MagickFalse)
              image->colormap[i].opacity=gamma_map[
                ScaleQuantumToMap(image->colormap[i].opacity)];
            else
              image->colormap[i].opacity=(Quantum) QuantumRange-
                gamma_map[ScaleQuantumToMap((Quantum) (QuantumRange-
                image->colormap[i].opacity))];
          }
      }
    }
  /*
    Gamma-correct image.
  */
  status=MagickTrue;
  progress=0;
  exception=(&image->exception);
  image_view=AcquireCacheView(image);
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    register IndexPacket
      *restrict indexes;

    register PixelPacket
      *restrict q;

    register ssize_t
      x;

    if (status == MagickFalse)
      continue;
    q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
    if (q == (PixelPacket *) NULL)
      {
        status=MagickFalse;
        continue;
      }
    indexes=GetCacheViewAuthenticIndexQueue(image_view);
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      if (channel == DefaultChannels)
        {
          q->red=gamma_map[ScaleQuantumToMap(q->red)];
          q->green=gamma_map[ScaleQuantumToMap(q->green)];
          q->blue=gamma_map[ScaleQuantumToMap(q->blue)];
        }
      else
        {
          if ((channel & RedChannel) != 0)
            q->red=gamma_map[ScaleQuantumToMap(q->red)];
          if ((channel & GreenChannel) != 0)
            q->green=gamma_map[ScaleQuantumToMap(q->green)];
          if ((channel & BlueChannel) != 0)
            q->blue=gamma_map[ScaleQuantumToMap(q->blue)];
          if ((channel & OpacityChannel) != 0)
            {
              if (image->matte == MagickFalse)
                q->opacity=gamma_map[ScaleQuantumToMap(q->opacity)];
              else
                q->opacity=(Quantum) QuantumRange-gamma_map[
                  ScaleQuantumToMap((Quantum) GetAlphaPixelComponent(q))];
            }
        }
      q++;
    }
    if (((channel & IndexChannel) != 0) &&
        (image->colorspace == CMYKColorspace))
      for (x=0; x < (ssize_t) image->columns; x++)
        indexes[x]=gamma_map[ScaleQuantumToMap(indexes[x])];
    if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
      status=MagickFalse;
    if (image->progress_monitor != (MagickProgressMonitor) NULL)
      {
        MagickBooleanType
          proceed;

#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp critical (MagickCore_GammaImageChannel)
#endif
        proceed=SetImageProgress(image,GammaCorrectImageTag,progress++,
          image->rows);
        if (proceed == MagickFalse)
          status=MagickFalse;
      }
  }
  image_view=DestroyCacheView(image_view);
  gamma_map=(Quantum *) RelinquishMagickMemory(gamma_map);
  if (image->gamma != 0.0)
    image->gamma*=gamma;
  return(status);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%     H a l d C l u t I m a g e                                               %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  HaldClutImage() applies a Hald color lookup table to the image.  A Hald
%  color lookup table is a 3-dimensional color cube mapped to 2 dimensions.
%  Create it with the HALD coder.  You can apply any color transformation to
%  the Hald image and then use this method to apply the transform to the
%  image.
%
%  The format of the HaldClutImage method is:
%
%      MagickBooleanType HaldClutImage(Image *image,Image *hald_image)
%      MagickBooleanType HaldClutImageChannel(Image *image,
%        const ChannelType channel,Image *hald_image)
%
%  A description of each parameter follows:
%
%    o image: the image, which is replaced by indexed CLUT values
%
%    o hald_image: the color lookup table image for replacement color values.
%
%    o channel: the channel.
%
*/

static inline size_t MagickMin(const size_t x,const size_t y)
{
  if (x < y)
    return(x);
  return(y);
}

MagickExport MagickBooleanType HaldClutImage(Image *image,
  const Image *hald_image)
{
  return(HaldClutImageChannel(image,DefaultChannels,hald_image));
}

MagickExport MagickBooleanType HaldClutImageChannel(Image *image,
  const ChannelType channel,const Image *hald_image)
{
#define HaldClutImageTag  "Clut/Image"

  typedef struct _HaldInfo
  {
    MagickRealType
      x,
      y,
      z;
  } HaldInfo;

  CacheView
    *hald_view,
    *image_view;

  double
    width;

  ExceptionInfo
    *exception;

  MagickBooleanType
    status;

  MagickOffsetType
    progress;

  MagickPixelPacket
    zero;

  size_t
    cube_size,
    length,
    level;

  ssize_t
    y;

  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  assert(hald_image != (Image *) NULL);
  assert(hald_image->signature == MagickSignature);
  if (SetImageStorageClass(image,DirectClass) == MagickFalse)
    return(MagickFalse);
  if (image->matte == MagickFalse)
    (void) SetImageAlphaChannel(image,OpaqueAlphaChannel);
  /*
    Hald clut image.
  */
  status=MagickTrue;
  progress=0;
  length=MagickMin(hald_image->columns,hald_image->rows);
  for (level=2; (level*level*level) < length; level++) ;
  level*=level;
  cube_size=level*level;
  width=(double) hald_image->columns;
  GetMagickPixelPacket(hald_image,&zero);
  exception=(&image->exception);
  image_view=AcquireCacheView(image);
  hald_view=AcquireCacheView(hald_image);
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    double
      offset;

    HaldInfo
      point;

    MagickPixelPacket
      pixel,
      pixel1,
      pixel2,
      pixel3,
      pixel4;

    register IndexPacket
      *restrict indexes;

    register PixelPacket
      *restrict q;

    register ssize_t
      x;

    if (status == MagickFalse)
      continue;
    q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
    if (q == (PixelPacket *) NULL)
      {
        status=MagickFalse;
        continue;
      }
    indexes=GetCacheViewAuthenticIndexQueue(hald_view);
    pixel=zero;
    pixel1=zero;
    pixel2=zero;
    pixel3=zero;
    pixel4=zero;
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      point.x=QuantumScale*(level-1.0)*q->red;
      point.y=QuantumScale*(level-1.0)*q->green;
      point.z=QuantumScale*(level-1.0)*q->blue;
      offset=point.x+level*floor(point.y)+cube_size*floor(point.z);
      point.x-=floor(point.x);
      point.y-=floor(point.y);
      point.z-=floor(point.z);
      (void) InterpolateMagickPixelPacket(image,hald_view,
        UndefinedInterpolatePixel,fmod(offset,width),floor(offset/width),
        &pixel1,exception);
      (void) InterpolateMagickPixelPacket(image,hald_view,
        UndefinedInterpolatePixel,fmod(offset+level,width),floor((offset+level)/
        width),&pixel2,exception);
      MagickPixelCompositeAreaBlend(&pixel1,pixel1.opacity,&pixel2,
        pixel2.opacity,point.y,&pixel3);
      offset+=cube_size;
      (void) InterpolateMagickPixelPacket(image,hald_view,
        UndefinedInterpolatePixel,fmod(offset,width),floor(offset/width),
        &pixel1,exception);
      (void) InterpolateMagickPixelPacket(image,hald_view,
        UndefinedInterpolatePixel,fmod(offset+level,width),floor((offset+level)/
        width),&pixel2,exception);
      MagickPixelCompositeAreaBlend(&pixel1,pixel1.opacity,&pixel2,
        pixel2.opacity,point.y,&pixel4);
      MagickPixelCompositeAreaBlend(&pixel3,pixel3.opacity,&pixel4,
        pixel4.opacity,point.z,&pixel);
      if ((channel & RedChannel) != 0)
        SetRedPixelComponent(q,ClampRedPixelComponent(&pixel));
      if ((channel & GreenChannel) != 0)
        SetGreenPixelComponent(q,ClampGreenPixelComponent(&pixel));
      if ((channel & BlueChannel) != 0)
        SetBluePixelComponent(q,ClampBluePixelComponent(&pixel));
      if (((channel & OpacityChannel) != 0) && (image->matte != MagickFalse))
        SetOpacityPixelComponent(q,ClampOpacityPixelComponent(&pixel));
      if (((channel & IndexChannel) != 0) &&
          (image->colorspace == CMYKColorspace))
        indexes[x]=ClampToQuantum(pixel.index);
      q++;
    }
    if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
      status=MagickFalse;
    if (image->progress_monitor != (MagickProgressMonitor) NULL)
      {
        MagickBooleanType
          proceed;

#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp critical (MagickCore_HaldClutImageChannel)
#endif
        proceed=SetImageProgress(image,HaldClutImageTag,progress++,image->rows);
        if (proceed == MagickFalse)
          status=MagickFalse;
      }
  }
  hald_view=DestroyCacheView(hald_view);
  image_view=DestroyCacheView(image_view);
  return(status);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%     L e v e l I m a g e                                                     %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  LevelImage() adjusts the levels of a particular image channel by
%  scaling the colors falling between specified white and black points to
%  the full available quantum range.
%
%  The parameters provided represent the black, and white points.  The black
%  point specifies the darkest color in the image. Colors darker than the
%  black point are set to zero.  White point specifies the lightest color in
%  the image.  Colors brighter than the white point are set to the maximum
%  quantum value.
%
%  If a '!' flag is given, map black and white colors to the given levels
%  rather than mapping those levels to black and white.  See
%  LevelizeImageChannel() and LevelizeImageChannel(), below.
%
%  Gamma specifies a gamma correction to apply to the image.
%
%  The format of the LevelImage method is:
%
%      MagickBooleanType LevelImage(Image *image,const char *levels)
%
%  A description of each parameter follows:
%
%    o image: the image.
%
%    o levels: Specify the levels where the black and white points have the
%      range of 0-QuantumRange, and gamma has the range 0-10 (e.g. 10x90%+2).
%      A '!' flag inverts the re-mapping.
%
*/

MagickExport MagickBooleanType LevelImage(Image *image,const char *levels)
{
  double
    black_point,
    gamma,
    white_point;

  GeometryInfo
    geometry_info;

  MagickBooleanType
    status;

  MagickStatusType
    flags;

  /*
    Parse levels.
  */
  if (levels == (char *) NULL)
    return(MagickFalse);
  flags=ParseGeometry(levels,&geometry_info);
  black_point=geometry_info.rho;
  white_point=(double) QuantumRange;
  if ((flags & SigmaValue) != 0)
    white_point=geometry_info.sigma;
  gamma=1.0;
  if ((flags & XiValue) != 0)
    gamma=geometry_info.xi;
  if ((flags & PercentValue) != 0)
    {
      black_point*=(double) image->columns*image->rows/100.0;
      white_point*=(double) image->columns*image->rows/100.0;
    }
  if ((flags & SigmaValue) == 0)
    white_point=(double) QuantumRange-black_point;
  if ((flags & AspectValue ) == 0)
    status=LevelImageChannel(image,DefaultChannels,black_point,white_point,
      gamma);
  else
    status=LevelizeImage(image,black_point,white_point,gamma);
  return(status);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%     L e v e l i z e I m a g e                                               %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  LevelizeImage() applies the normal level operation to the image, spreading
%  out the values between the black and white points over the entire range of
%  values.  Gamma correction is also applied after the values has been mapped.
%
%  It is typically used to improve image contrast, or to provide a controlled
%  linear threshold for the image. If the black and white points are set to
%  the minimum and maximum values found in the image, the image can be
%  normalized.  or by swapping black and white values, negate the image.
%
%  The format of the LevelizeImage method is:
%
%      MagickBooleanType LevelizeImage(Image *image,const double black_point,
%        const double white_point,const double gamma)
%      MagickBooleanType LevelizeImageChannel(Image *image,
%        const ChannelType channel,const double black_point,
%        const double white_point,const double gamma)
%
%  A description of each parameter follows:
%
%    o image: the image.
%
%    o channel: the channel.
%
%    o black_point: The level which is to be mapped to zero (black)
%
%    o white_point: The level which is to be mapped to QuantiumRange (white)
%
%    o gamma: adjust gamma by this factor before mapping values.
%             use 1.0 for purely linear stretching of image color values
%
*/
MagickExport MagickBooleanType LevelImageChannel(Image *image,
  const ChannelType channel,const double black_point,const double white_point,
  const double gamma)
{
#define LevelImageTag  "Level/Image"
#define LevelQuantum(x) (ClampToQuantum((MagickRealType) QuantumRange* \
  pow(scale*((double) (x)-black_point),1.0/gamma)))

  CacheView
    *image_view;

  ExceptionInfo
    *exception;

  MagickBooleanType
    status;

  MagickOffsetType
    progress;

  register double
    scale;

  register ssize_t
    i;

  ssize_t
    y;

  /*
    Allocate and initialize levels map.
  */
  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  scale=(white_point != black_point) ? 1.0/(white_point-black_point) : 1.0;
  if (image->storage_class == PseudoClass)
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
    for (i=0; i < (ssize_t) image->colors; i++)
    {
      /*
        Level colormap.
      */
      if ((channel & RedChannel) != 0)
        image->colormap[i].red=LevelQuantum(image->colormap[i].red);
      if ((channel & GreenChannel) != 0)
        image->colormap[i].green=LevelQuantum(image->colormap[i].green);
      if ((channel & BlueChannel) != 0)
        image->colormap[i].blue=LevelQuantum(image->colormap[i].blue);
      if ((channel & OpacityChannel) != 0)
        image->colormap[i].opacity=LevelQuantum(image->colormap[i].opacity);
      }
  /*
    Level image.
  */
  status=MagickTrue;
  progress=0;
  exception=(&image->exception);
  image_view=AcquireCacheView(image);
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    register IndexPacket
      *restrict indexes;

    register PixelPacket
      *restrict q;

    register ssize_t
      x;

    if (status == MagickFalse)
      continue;
    q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
    if (q == (PixelPacket *) NULL)
      {
        status=MagickFalse;
        continue;
      }
    indexes=GetCacheViewAuthenticIndexQueue(image_view);
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      if ((channel & RedChannel) != 0)
        q->red=LevelQuantum(q->red);
      if ((channel & GreenChannel) != 0)
        q->green=LevelQuantum(q->green);
      if ((channel & BlueChannel) != 0)
        q->blue=LevelQuantum(q->blue);
      if (((channel & OpacityChannel) != 0) &&
          (image->matte == MagickTrue))
        q->opacity=(Quantum) (QuantumRange-LevelQuantum(QuantumRange-
          q->opacity));
      if (((channel & IndexChannel) != 0) &&
          (image->colorspace == CMYKColorspace))
        indexes[x]=LevelQuantum(indexes[x]);
      q++;
    }
    if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
      status=MagickFalse;
    if (image->progress_monitor != (MagickProgressMonitor) NULL)
      {
        MagickBooleanType
          proceed;

#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp critical (MagickCore_LevelImageChannel)
#endif
        proceed=SetImageProgress(image,LevelImageTag,progress++,image->rows);
        if (proceed == MagickFalse)
          status=MagickFalse;
      }
  }
  image_view=DestroyCacheView(image_view);
  return(status);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%     L e v e l i z e I m a g e C h a n n e l                                 %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  LevelizeImageChannel() applies the reversed LevelImage() operation to just
%  the specific channels specified.  It compresses the full range of color
%  values, so that they lie between the given black and white points. Gamma is
%  applied before the values are mapped.
%
%  LevelizeImageChannel() can be called with by using a +level command line
%  API option, or using a '!' on a -level or LevelImage() geometry string.
%
%  It can be used for example de-contrast a greyscale image to the exact
%  levels specified.  Or by using specific levels for each channel of an image
%  you can convert a gray-scale image to any linear color gradient, according
%  to those levels.
%
%  The format of the LevelizeImageChannel method is:
%
%      MagickBooleanType LevelizeImageChannel(Image *image,
%        const ChannelType channel,const char *levels)
%
%  A description of each parameter follows:
%
%    o image: the image.
%
%    o channel: the channel.
%
%    o black_point: The level to map zero (black) to.
%
%    o white_point: The level to map QuantiumRange (white) to.
%
%    o gamma: adjust gamma by this factor before mapping values.
%
*/

MagickExport MagickBooleanType LevelizeImage(Image *image,
  const double black_point,const double white_point,const double gamma)
{
  MagickBooleanType
    status;

  status=LevelizeImageChannel(image,DefaultChannels,black_point,white_point,
    gamma);
  return(status);
}

MagickExport MagickBooleanType LevelizeImageChannel(Image *image,
  const ChannelType channel,const double black_point,const double white_point,
  const double gamma)
{
#define LevelizeImageTag  "Levelize/Image"
#define LevelizeValue(x) (ClampToQuantum(((MagickRealType) \
  pow((double)(QuantumScale*(x)),1.0/gamma))*(white_point-black_point)+ \
  black_point))

  CacheView
    *image_view;

  ExceptionInfo
    *exception;

  MagickBooleanType
    status;

  MagickOffsetType
    progress;

  register ssize_t
    i;

  ssize_t
    y;

  /*
    Allocate and initialize levels map.
  */
  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  if (image->storage_class == PseudoClass)
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
    for (i=0; i < (ssize_t) image->colors; i++)
    {
      /*
        Level colormap.
      */
      if ((channel & RedChannel) != 0)
        image->colormap[i].red=LevelizeValue(image->colormap[i].red);
      if ((channel & GreenChannel) != 0)
        image->colormap[i].green=LevelizeValue(image->colormap[i].green);
      if ((channel & BlueChannel) != 0)
        image->colormap[i].blue=LevelizeValue(image->colormap[i].blue);
      if ((channel & OpacityChannel) != 0)
        image->colormap[i].opacity=LevelizeValue(image->colormap[i].opacity);
    }
  /*
    Level image.
  */
  status=MagickTrue;
  progress=0;
  exception=(&image->exception);
  image_view=AcquireCacheView(image);
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    register IndexPacket
      *restrict indexes;

    register PixelPacket
      *restrict q;

    register ssize_t
      x;

    if (status == MagickFalse)
      continue;
    q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
    if (q == (PixelPacket *) NULL)
      {
        status=MagickFalse;
        continue;
      }
    indexes=GetCacheViewAuthenticIndexQueue(image_view);
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      if ((channel & RedChannel) != 0)
        q->red=LevelizeValue(q->red);
      if ((channel & GreenChannel) != 0)
        q->green=LevelizeValue(q->green);
      if ((channel & BlueChannel) != 0)
        q->blue=LevelizeValue(q->blue);
      if (((channel & OpacityChannel) != 0) &&
          (image->matte == MagickTrue))
        q->opacity=LevelizeValue(q->opacity);
      if (((channel & IndexChannel) != 0) &&
          (image->colorspace == CMYKColorspace))
        indexes[x]=LevelizeValue(indexes[x]);
      q++;
    }
    if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
      status=MagickFalse;
    if (image->progress_monitor != (MagickProgressMonitor) NULL)
      {
        MagickBooleanType
          proceed;

#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp critical (MagickCore_LevelizeImageChannel)
#endif
        proceed=SetImageProgress(image,LevelizeImageTag,progress++,image->rows);
        if (proceed == MagickFalse)
          status=MagickFalse;
      }
  }
  image_view=DestroyCacheView(image_view);
  return(status);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%     L e v e l I m a g e C o l o r s                                         %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  LevelImageColor() maps the given color to "black" and "white" values,
%  linearly spreading out the colors, and level values on a channel by channel
%  bases, as per LevelImage().  The given colors allows you to specify
%  different level ranges for each of the color channels separately.
%
%  If the boolean 'invert' is set true the image values will modifyed in the
%  reverse direction. That is any existing "black" and "white" colors in the
%  image will become the color values given, with all other values compressed
%  appropriatally.  This effectivally maps a greyscale gradient into the given
%  color gradient.
%
%  The format of the LevelColorsImageChannel method is:
%
%    MagickBooleanType LevelColorsImage(Image *image,
%      const MagickPixelPacket *black_color,
%      const MagickPixelPacket *white_color,const MagickBooleanType invert)
%    MagickBooleanType LevelColorsImageChannel(Image *image,
%      const ChannelType channel,const MagickPixelPacket *black_color,
%      const MagickPixelPacket *white_color,const MagickBooleanType invert)
%
%  A description of each parameter follows:
%
%    o image: the image.
%
%    o channel: the channel.
%
%    o black_color: The color to map black to/from
%
%    o white_point: The color to map white to/from
%
%    o invert: if true map the colors (levelize), rather than from (level)
%
*/

MagickExport MagickBooleanType LevelColorsImage(Image *image,
  const MagickPixelPacket *black_color,const MagickPixelPacket *white_color,
  const MagickBooleanType invert)
{
  MagickBooleanType
    status;

  status=LevelColorsImageChannel(image,DefaultChannels,black_color,white_color,
    invert);
  return(status);
}

MagickExport MagickBooleanType LevelColorsImageChannel(Image *image,
  const ChannelType channel,const MagickPixelPacket *black_color,
  const MagickPixelPacket *white_color,const MagickBooleanType invert)
{
  MagickStatusType
    status;

  /*
    Allocate and initialize levels map.
  */
  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  status=MagickFalse;
  if (invert == MagickFalse)
    {
      if ((channel & RedChannel) != 0)
        status|=LevelImageChannel(image,RedChannel,
          black_color->red,white_color->red,(double) 1.0);
      if ((channel & GreenChannel) != 0)
        status|=LevelImageChannel(image,GreenChannel,
          black_color->green,white_color->green,(double) 1.0);
      if ((channel & BlueChannel) != 0)
        status|=LevelImageChannel(image,BlueChannel,
          black_color->blue,white_color->blue,(double) 1.0);
      if (((channel & OpacityChannel) != 0) &&
          (image->matte == MagickTrue))
        status|=LevelImageChannel(image,OpacityChannel,
          black_color->opacity,white_color->opacity,(double) 1.0);
      if (((channel & IndexChannel) != 0) &&
          (image->colorspace == CMYKColorspace))
        status|=LevelImageChannel(image,IndexChannel,
          black_color->index,white_color->index,(double) 1.0);
    }
  else
    {
      if ((channel & RedChannel) != 0)
        status|=LevelizeImageChannel(image,RedChannel,
          black_color->red,white_color->red,(double) 1.0);
      if ((channel & GreenChannel) != 0)
        status|=LevelizeImageChannel(image,GreenChannel,
          black_color->green,white_color->green,(double) 1.0);
      if ((channel & BlueChannel) != 0)
        status|=LevelizeImageChannel(image,BlueChannel,
          black_color->blue,white_color->blue,(double) 1.0);
      if (((channel & OpacityChannel) != 0) &&
          (image->matte == MagickTrue))
        status|=LevelizeImageChannel(image,OpacityChannel,
          black_color->opacity,white_color->opacity,(double) 1.0);
      if (((channel & IndexChannel) != 0) &&
          (image->colorspace == CMYKColorspace))
        status|=LevelizeImageChannel(image,IndexChannel,
          black_color->index,white_color->index,(double) 1.0);
    }
  return(status == 0 ? MagickFalse : MagickTrue);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%     L i n e a r S t r e t c h I m a g e                                     %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  The LinearStretchImage() discards any pixels below the black point and
%  above the white point and levels the remaining pixels.
%
%  The format of the LinearStretchImage method is:
%
%      MagickBooleanType LinearStretchImage(Image *image,
%        const double black_point,const double white_point)
%
%  A description of each parameter follows:
%
%    o image: the image.
%
%    o black_point: the black point.
%
%    o white_point: the white point.
%
*/
MagickExport MagickBooleanType LinearStretchImage(Image *image,
  const double black_point,const double white_point)
{
#define LinearStretchImageTag  "LinearStretch/Image"

  ExceptionInfo
    *exception;

  MagickBooleanType
    status;

  MagickRealType
    *histogram,
    intensity;

  ssize_t
    black,
    white,
    y;

  /*
    Allocate histogram and linear map.
  */
  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  histogram=(MagickRealType *) AcquireQuantumMemory(MaxMap+1UL,
    sizeof(*histogram));
  if (histogram == (MagickRealType *) NULL)
    ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
      image->filename);
  /*
    Form histogram.
  */
  (void) ResetMagickMemory(histogram,0,(MaxMap+1)*sizeof(*histogram));
  exception=(&image->exception);
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    register const PixelPacket
      *restrict p;

    register ssize_t
      x;

    p=GetVirtualPixels(image,0,y,image->columns,1,exception);
    if (p == (const PixelPacket *) NULL)
      break;
    for (x=(ssize_t) image->columns-1; x >= 0; x--)
    {
      histogram[ScaleQuantumToMap(PixelIntensityToQuantum(p))]++;
      p++;
    }
  }
  /*
    Find the histogram boundaries by locating the black and white point levels.
  */
  intensity=0.0;
  for (black=0; black < (ssize_t) MaxMap; black++)
  {
    intensity+=histogram[black];
    if (intensity >= black_point)
      break;
  }
  intensity=0.0;
  for (white=(ssize_t) MaxMap; white != 0; white--)
  {
    intensity+=histogram[white];
    if (intensity >= white_point)
      break;
  }
  histogram=(MagickRealType *) RelinquishMagickMemory(histogram);
  status=LevelImageChannel(image,DefaultChannels,(double) black,(double) white,
    1.0);
  return(status);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%     M o d u l a t e I m a g e                                               %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  ModulateImage() lets you control the brightness, saturation, and hue
%  of an image.  Modulate represents the brightness, saturation, and hue
%  as one parameter (e.g. 90,150,100).  If the image colorspace is HSL, the
%  modulation is lightness, saturation, and hue.  And if the colorspace is
%  HWB, use blackness, whiteness, and hue.
%
%  The format of the ModulateImage method is:
%
%      MagickBooleanType ModulateImage(Image *image,const char *modulate)
%
%  A description of each parameter follows:
%
%    o image: the image.
%
%    o modulate: Define the percent change in brightness, saturation, and
%      hue.
%
*/

static void ModulateHSB(const double percent_hue,
  const double percent_saturation,const double percent_brightness,
  Quantum *red,Quantum *green,Quantum *blue)
{
  double
    brightness,
    hue,
    saturation;

  /*
    Increase or decrease color brightness, saturation, or hue.
  */
  assert(red != (Quantum *) NULL);
  assert(green != (Quantum *) NULL);
  assert(blue != (Quantum *) NULL);
  ConvertRGBToHSB(*red,*green,*blue,&hue,&saturation,&brightness);
  hue+=0.5*(0.01*percent_hue-1.0);
  while (hue < 0.0)
    hue+=1.0;
  while (hue > 1.0)
    hue-=1.0;
  saturation*=0.01*percent_saturation;
  brightness*=0.01*percent_brightness;
  ConvertHSBToRGB(hue,saturation,brightness,red,green,blue);
}

static void ModulateHSL(const double percent_hue,
  const double percent_saturation,const double percent_lightness,
  Quantum *red,Quantum *green,Quantum *blue)
{
  double
    hue,
    lightness,
    saturation;

  /*
    Increase or decrease color lightness, saturation, or hue.
  */
  assert(red != (Quantum *) NULL);
  assert(green != (Quantum *) NULL);
  assert(blue != (Quantum *) NULL);
  ConvertRGBToHSL(*red,*green,*blue,&hue,&saturation,&lightness);
  hue+=0.5*(0.01*percent_hue-1.0);
  while (hue < 0.0)
    hue+=1.0;
  while (hue > 1.0)
    hue-=1.0;
  saturation*=0.01*percent_saturation;
  lightness*=0.01*percent_lightness;
  ConvertHSLToRGB(hue,saturation,lightness,red,green,blue);
}

static void ModulateHWB(const double percent_hue,const double percent_whiteness,  const double percent_blackness,Quantum *red,Quantum *green,Quantum *blue)
{
  double
    blackness,
    hue,
    whiteness;

  /*
    Increase or decrease color blackness, whiteness, or hue.
  */
  assert(red != (Quantum *) NULL);
  assert(green != (Quantum *) NULL);
  assert(blue != (Quantum *) NULL);
  ConvertRGBToHWB(*red,*green,*blue,&hue,&whiteness,&blackness);
  hue+=0.5*(0.01*percent_hue-1.0);
  while (hue < 0.0)
    hue+=1.0;
  while (hue > 1.0)
    hue-=1.0;
  blackness*=0.01*percent_blackness;
  whiteness*=0.01*percent_whiteness;
  ConvertHWBToRGB(hue,whiteness,blackness,red,green,blue);
}

MagickExport MagickBooleanType ModulateImage(Image *image,const char *modulate)
{
#define ModulateImageTag  "Modulate/Image"

  CacheView
    *image_view;

  ColorspaceType
    colorspace;

  const char
    *artifact;

  double
    percent_brightness,
    percent_hue,
    percent_saturation;

  ExceptionInfo
    *exception;

  GeometryInfo
    geometry_info;

  MagickBooleanType
    status;

  MagickOffsetType
    progress;

  MagickStatusType
    flags;

  register ssize_t
    i;

  ssize_t
    y;

  /*
    Initialize modulate table.
  */
  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  if (modulate == (char *) NULL)
    return(MagickFalse);
  flags=ParseGeometry(modulate,&geometry_info);
  percent_brightness=geometry_info.rho;
  percent_saturation=geometry_info.sigma;
  if ((flags & SigmaValue) == 0)
    percent_saturation=100.0;
  percent_hue=geometry_info.xi;
  if ((flags & XiValue) == 0)
    percent_hue=100.0;
  colorspace=UndefinedColorspace;
  artifact=GetImageArtifact(image,"modulate:colorspace");
  if (artifact != (const char *) NULL)
    colorspace=(ColorspaceType) ParseMagickOption(MagickColorspaceOptions,
      MagickFalse,artifact);
  if (image->storage_class == PseudoClass)
    {
      /*
        Modulate colormap.
      */
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
      for (i=0; i < (ssize_t) image->colors; i++)
        switch (colorspace)
        {
          case HSBColorspace:
          {
            ModulateHSB(percent_hue,percent_saturation,percent_brightness,
              &image->colormap[i].red,&image->colormap[i].green,
              &image->colormap[i].blue);
            break;
          }
          case HSLColorspace:
          default:
          {
            ModulateHSL(percent_hue,percent_saturation,percent_brightness,
              &image->colormap[i].red,&image->colormap[i].green,
              &image->colormap[i].blue);
            break;
          }
          case HWBColorspace:
          {
            ModulateHWB(percent_hue,percent_saturation,percent_brightness,
              &image->colormap[i].red,&image->colormap[i].green,
              &image->colormap[i].blue);
            break;
          }
        }
    }
  /*
    Modulate image.
  */
  status=MagickTrue;
  progress=0;
  exception=(&image->exception);
  image_view=AcquireCacheView(image);
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    register PixelPacket
      *restrict q;

    register ssize_t
      x;

    if (status == MagickFalse)
      continue;
    q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
    if (q == (PixelPacket *) NULL)
      {
        status=MagickFalse;
        continue;
      }
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      switch (colorspace)
      {
        case HSBColorspace:
        {
          ModulateHSB(percent_hue,percent_saturation,percent_brightness,
            &q->red,&q->green,&q->blue);
          break;
        }
        case HSLColorspace:
        default:
        {
          ModulateHSL(percent_hue,percent_saturation,percent_brightness,
            &q->red,&q->green,&q->blue);
          break;
        }
        case HWBColorspace:
        {
          ModulateHWB(percent_hue,percent_saturation,percent_brightness,
            &q->red,&q->green,&q->blue);
          break;
        }
      }
      q++;
    }
    if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
      status=MagickFalse;
    if (image->progress_monitor != (MagickProgressMonitor) NULL)
      {
        MagickBooleanType
          proceed;

#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp critical (MagickCore_ModulateImage)
#endif
        proceed=SetImageProgress(image,ModulateImageTag,progress++,image->rows);
        if (proceed == MagickFalse)
          status=MagickFalse;
      }
  }
  image_view=DestroyCacheView(image_view);
  return(status);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%     N e g a t e I m a g e                                                   %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  NegateImage() negates the colors in the reference image.  The grayscale
%  option means that only grayscale values within the image are negated.
%
%  The format of the NegateImageChannel method is:
%
%      MagickBooleanType NegateImage(Image *image,
%        const MagickBooleanType grayscale)
%      MagickBooleanType NegateImageChannel(Image *image,
%        const ChannelType channel,const MagickBooleanType grayscale)
%
%  A description of each parameter follows:
%
%    o image: the image.
%
%    o channel: the channel.
%
%    o grayscale: If MagickTrue, only negate grayscale pixels within the image.
%
*/

MagickExport MagickBooleanType NegateImage(Image *image,
  const MagickBooleanType grayscale)
{
  MagickBooleanType
    status;

  status=NegateImageChannel(image,DefaultChannels,grayscale);
  return(status);
}

MagickExport MagickBooleanType NegateImageChannel(Image *image,
  const ChannelType channel,const MagickBooleanType grayscale)
{
#define NegateImageTag  "Negate/Image"

  CacheView
    *image_view;

  ExceptionInfo
    *exception;

  MagickBooleanType
    status;

  MagickOffsetType
    progress;

  register ssize_t
    i;

  ssize_t
    y;

  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  if (image->storage_class == PseudoClass)
    {
      /*
        Negate colormap.
      */
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
      for (i=0; i < (ssize_t) image->colors; i++)
      {
        if (grayscale != MagickFalse)
          if ((image->colormap[i].red != image->colormap[i].green) ||
              (image->colormap[i].green != image->colormap[i].blue))
            continue;
        if ((channel & RedChannel) != 0)
          image->colormap[i].red=(Quantum) QuantumRange-
            image->colormap[i].red;
        if ((channel & GreenChannel) != 0)
          image->colormap[i].green=(Quantum) QuantumRange-
            image->colormap[i].green;
        if ((channel & BlueChannel) != 0)
          image->colormap[i].blue=(Quantum) QuantumRange-
            image->colormap[i].blue;
      }
    }
  /*
    Negate image.
  */
  status=MagickTrue;
  progress=0;
  exception=(&image->exception);
  image_view=AcquireCacheView(image);
  if (grayscale != MagickFalse)
    {
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
      for (y=0; y < (ssize_t) image->rows; y++)
      {
        MagickBooleanType
          sync;

        register IndexPacket
          *restrict indexes;

        register PixelPacket
          *restrict q;

        register ssize_t
          x;

        if (status == MagickFalse)
          continue;
        q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,
          exception);
        if (q == (PixelPacket *) NULL)
          {
            status=MagickFalse;
            continue;
          }
        indexes=GetCacheViewAuthenticIndexQueue(image_view);
        for (x=0; x < (ssize_t) image->columns; x++)
        {
          if ((q->red != q->green) || (q->green != q->blue))
            {
              q++;
              continue;
            }
          if ((channel & RedChannel) != 0)
            q->red=(Quantum) QuantumRange-q->red;
          if ((channel & GreenChannel) != 0)
            q->green=(Quantum) QuantumRange-q->green;
          if ((channel & BlueChannel) != 0)
            q->blue=(Quantum) QuantumRange-q->blue;
          if ((channel & OpacityChannel) != 0)
            q->opacity=(Quantum) QuantumRange-q->opacity;
          if (((channel & IndexChannel) != 0) &&
              (image->colorspace == CMYKColorspace))
            indexes[x]=(IndexPacket) QuantumRange-indexes[x];
          q++;
        }
        sync=SyncCacheViewAuthenticPixels(image_view,exception);
        if (sync == MagickFalse)
          status=MagickFalse;
        if (image->progress_monitor != (MagickProgressMonitor) NULL)
          {
            MagickBooleanType
              proceed;

#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp critical (MagickCore_NegateImageChannel)
#endif
            proceed=SetImageProgress(image,NegateImageTag,progress++,
              image->rows);
            if (proceed == MagickFalse)
              status=MagickFalse;
          }
      }
      image_view=DestroyCacheView(image_view);
      return(MagickTrue);
    }
  /*
    Negate image.
  */
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    register IndexPacket
      *restrict indexes;

    register PixelPacket
      *restrict q;

    register ssize_t
      x;

    if (status == MagickFalse)
      continue;
    q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
    if (q == (PixelPacket *) NULL)
      {
        status=MagickFalse;
        continue;
      }
    indexes=GetCacheViewAuthenticIndexQueue(image_view);
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      if ((channel & RedChannel) != 0)
        q->red=(Quantum) QuantumRange-q->red;
      if ((channel & GreenChannel) != 0)
        q->green=(Quantum) QuantumRange-q->green;
      if ((channel & BlueChannel) != 0)
        q->blue=(Quantum) QuantumRange-q->blue;
      if ((channel & OpacityChannel) != 0)
        q->opacity=(Quantum) QuantumRange-q->opacity;
      if (((channel & IndexChannel) != 0) &&
          (image->colorspace == CMYKColorspace))
        indexes[x]=(IndexPacket) QuantumRange-indexes[x];
      q++;
    }
    if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
      status=MagickFalse;
    if (image->progress_monitor != (MagickProgressMonitor) NULL)
      {
        MagickBooleanType
          proceed;

#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp critical (MagickCore_NegateImageChannel)
#endif
        proceed=SetImageProgress(image,NegateImageTag,progress++,image->rows);
        if (proceed == MagickFalse)
          status=MagickFalse;
      }
  }
  image_view=DestroyCacheView(image_view);
  return(status);
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%     N o r m a l i z e I m a g e                                             %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  The NormalizeImage() method enhances the contrast of a color image by
%  mapping the darkest 2 percent of all pixel to black and the brightest
%  1 percent to white.
%
%  The format of the NormalizeImage method is:
%
%      MagickBooleanType NormalizeImage(Image *image)
%      MagickBooleanType NormalizeImageChannel(Image *image,
%        const ChannelType channel)
%
%  A description of each parameter follows:
%
%    o image: the image.
%
%    o channel: the channel.
%
*/

MagickExport MagickBooleanType NormalizeImage(Image *image)
{
  MagickBooleanType
    status;

  status=NormalizeImageChannel(image,DefaultChannels);
  return(status);
}

MagickExport MagickBooleanType NormalizeImageChannel(Image *image,
  const ChannelType channel)
{
  double
    black_point,
    white_point;

  black_point=(double) image->columns*image->rows*0.0015;
  white_point=(double) image->columns*image->rows*0.9995;
  return(ContrastStretchImageChannel(image,channel,black_point,white_point));
}

/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                             %
%                                                                             %
%                                                                             %
%     S i g m o i d a l C o n t r a s t I m a g e                             %
%                                                                             %
%                                                                             %
%                                                                             %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  SigmoidalContrastImage() adjusts the contrast of an image with a non-linear
%  sigmoidal contrast algorithm.  Increase the contrast of the image using a
%  sigmoidal transfer function without saturating highlights or shadows.
%  Contrast indicates how much to increase the contrast (0 is none; 3 is
%  typical; 20 is pushing it); mid-point indicates where midtones fall in the
%  resultant image (0 is white; 50% is middle-gray; 100% is black).  Set
%  sharpen to MagickTrue to increase the image contrast otherwise the contrast
%  is reduced.
%
%  The format of the SigmoidalContrastImage method is:
%
%      MagickBooleanType SigmoidalContrastImage(Image *image,
%        const MagickBooleanType sharpen,const char *levels)
%      MagickBooleanType SigmoidalContrastImageChannel(Image *image,
%        const ChannelType channel,const MagickBooleanType sharpen,
%        const double contrast,const double midpoint)
%
%  A description of each parameter follows:
%
%    o image: the image.
%
%    o channel: the channel.
%
%    o sharpen: Increase or decrease image contrast.
%
%    o alpha: strength of the contrast, the larger the number the more
%      'threshold-like' it becomes.
%
%    o beta: midpoint of the function as a color value 0 to QuantumRange.
%
*/

MagickExport MagickBooleanType SigmoidalContrastImage(Image *image,
  const MagickBooleanType sharpen,const char *levels)
{
  GeometryInfo
    geometry_info;

  MagickBooleanType
    status;

  MagickStatusType
    flags;

  flags=ParseGeometry(levels,&geometry_info);
  if ((flags & SigmaValue) == 0)
    geometry_info.sigma=1.0*QuantumRange/2.0;
  if ((flags & PercentValue) != 0)
    geometry_info.sigma=1.0*QuantumRange*geometry_info.sigma/100.0;
  status=SigmoidalContrastImageChannel(image,DefaultChannels,sharpen,
    geometry_info.rho,geometry_info.sigma);
  return(status);
}

MagickExport MagickBooleanType SigmoidalContrastImageChannel(Image *image,
  const ChannelType channel,const MagickBooleanType sharpen,
  const double contrast,const double midpoint)
{
#define SigmoidalContrastImageTag  "SigmoidalContrast/Image"

  CacheView
    *image_view;

  ExceptionInfo
    *exception;

  MagickBooleanType
    status;

  MagickOffsetType
    progress;

  MagickRealType
    *sigmoidal_map;

  register ssize_t
    i;

  ssize_t
    y;

  /*
    Allocate and initialize sigmoidal maps.
  */
  assert(image != (Image *) NULL);
  assert(image->signature == MagickSignature);
  if (image->debug != MagickFalse)
    (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
  sigmoidal_map=(MagickRealType *) AcquireQuantumMemory(MaxMap+1UL,
    sizeof(*sigmoidal_map));
  if (sigmoidal_map == (MagickRealType *) NULL)
    ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
      image->filename);
  (void) ResetMagickMemory(sigmoidal_map,0,(MaxMap+1)*sizeof(*sigmoidal_map));
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
  for (i=0; i <= (ssize_t) MaxMap; i++)
  {
    if (sharpen != MagickFalse)
      {
        sigmoidal_map[i]=(MagickRealType) ScaleMapToQuantum((MagickRealType)
          (MaxMap*((1.0/(1.0+exp(contrast*(midpoint/(double) QuantumRange-
          (double) i/MaxMap))))-(1.0/(1.0+exp(contrast*(midpoint/
          (double) QuantumRange)))))/((1.0/(1.0+exp(contrast*(midpoint/
          (double) QuantumRange-1.0))))-(1.0/(1.0+exp(contrast*(midpoint/
          (double) QuantumRange)))))+0.5));
        continue;
      }
    sigmoidal_map[i]=(MagickRealType) ScaleMapToQuantum((MagickRealType)
      (MaxMap*(QuantumScale*midpoint-log((1.0-(1.0/(1.0+exp(midpoint/
      (double) QuantumRange*contrast))+((double) i/MaxMap)*((1.0/
      (1.0+exp(contrast*(midpoint/(double) QuantumRange-1.0))))-(1.0/
      (1.0+exp(midpoint/(double) QuantumRange*contrast))))))/
      (1.0/(1.0+exp(midpoint/(double) QuantumRange*contrast))+
      ((double) i/MaxMap)*((1.0/(1.0+exp(contrast*(midpoint/
      (double) QuantumRange-1.0))))-(1.0/(1.0+exp(midpoint/
      (double) QuantumRange*contrast))))))/contrast)));
  }
  if (image->storage_class == PseudoClass)
    {
      /*
        Sigmoidal-contrast enhance colormap.
      */
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
      for (i=0; i < (ssize_t) image->colors; i++)
      {
        if ((channel & RedChannel) != 0)
          image->colormap[i].red=ClampToQuantum(sigmoidal_map[
            ScaleQuantumToMap(image->colormap[i].red)]);
        if ((channel & GreenChannel) != 0)
          image->colormap[i].green=ClampToQuantum(sigmoidal_map[
            ScaleQuantumToMap(image->colormap[i].green)]);
        if ((channel & BlueChannel) != 0)
          image->colormap[i].blue=ClampToQuantum(sigmoidal_map[
            ScaleQuantumToMap(image->colormap[i].blue)]);
        if ((channel & OpacityChannel) != 0)
          image->colormap[i].opacity=ClampToQuantum(sigmoidal_map[
            ScaleQuantumToMap(image->colormap[i].opacity)]);
      }
    }
  /*
    Sigmoidal-contrast enhance image.
  */
  status=MagickTrue;
  progress=0;
  exception=(&image->exception);
  image_view=AcquireCacheView(image);
#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp parallel for schedule(dynamic,4) shared(progress,status)
#endif
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    register IndexPacket
      *restrict indexes;

    register PixelPacket
      *restrict q;

    register ssize_t
      x;

    if (status == MagickFalse)
      continue;
    q=GetCacheViewAuthenticPixels(image_view,0,y,image->columns,1,exception);
    if (q == (PixelPacket *) NULL)
      {
        status=MagickFalse;
        continue;
      }
    indexes=GetCacheViewAuthenticIndexQueue(image_view);
    for (x=0; x < (ssize_t) image->columns; x++)
    {
      if ((channel & RedChannel) != 0)
        q->red=ClampToQuantum(sigmoidal_map[ScaleQuantumToMap(q->red)]);
      if ((channel & GreenChannel) != 0)
        q->green=ClampToQuantum(sigmoidal_map[ScaleQuantumToMap(q->green)]);
      if ((channel & BlueChannel) != 0)
        q->blue=ClampToQuantum(sigmoidal_map[ScaleQuantumToMap(q->blue)]);
      if ((channel & OpacityChannel) != 0)
        q->opacity=ClampToQuantum(sigmoidal_map[ScaleQuantumToMap(q->opacity)]);
      if (((channel & IndexChannel) != 0) &&
          (image->colorspace == CMYKColorspace))
        indexes[x]=(IndexPacket) ClampToQuantum(sigmoidal_map[
          ScaleQuantumToMap(indexes[x])]);
      q++;
    }
    if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
      status=MagickFalse;
    if (image->progress_monitor != (MagickProgressMonitor) NULL)
      {
        MagickBooleanType
          proceed;

#if defined(MAGICKCORE_OPENMP_SUPPORT)
  #pragma omp critical (MagickCore_SigmoidalContrastImageChannel)
#endif
        proceed=SetImageProgress(image,SigmoidalContrastImageTag,progress++,
          image->rows);
        if (proceed == MagickFalse)
          status=MagickFalse;
      }
  }
  image_view=DestroyCacheView(image_view);
  sigmoidal_map=(MagickRealType *) RelinquishMagickMemory(sigmoidal_map);
  return(status);
}

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