Colormap
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.