Use the following code in your script to load the library:

  LOADLIB "wh::graphics/filters.whlib";

Public Functions and Macros

GfxBlurCanvas		Blur canvas.
GfxGrayscaleCanvas		Convert a canvas to grayscale
GfxInvertCanvas		Invert the colors of the canvast
GfxMultiplyCanvas		Multiply a canvas with another canvas
GfxResizeImageBlob		Reprocess and resize an image
GfxUpdateCanvasAlpha		Update the alpha channel on a canvas