ImageMagick: MagickCore, C API for ImageMagick: Colormap Methods

AcquireImageColormap

AcquireImageColormap() allocates an image colormap and initializes it to a linear gray colorspace. If the image already has a colormap, it is replaced. AcquireImageColormap() returns MagickTrue if successful, otherwise MagickFalse if there is not enough memory.

The format of the AcquireImageColormap method is:

MagickBooleanType AcquireImageColormap(Image *image,const size_t colors,
  ExceptionInfo *exception)

A description of each parameter follows:

image: the image.
colors: the number of colors in the image colormap.
exception: return any errors or warnings in this structure.

CycleColormap

CycleColormap() displaces an image's colormap by a given number of positions. If you cycle the colormap a number of times you can produce a psychodelic effect.

WARNING: this assumes an images colormap is in a well know and defined order. Currently Imagemagick has no way of setting that order.

The format of the CycleColormapImage method is:

MagickBooleanType CycleColormapImage(Image *image,const ssize_t displace,
  ExceptionInfo *exception)

A description of each parameter follows:

image: the image.
displace: displace the colormap this amount.
exception: return any errors or warnings in this structure.