The IlvMorphologyFilter class lets you perform "fattening" or "thinning" of artwork. It is particularly useful for fattening or thinning an alpha channel.

The dilation (or erosion) kernel is a rectangle with a width of 2*x-radius+1 and a height of 2*y-radius+1 where radius is a user-specified value. In dilation, the output pixel is the individual component-wise maximum of the corresponding R,G,B,A values in the input image kernel rectangle. In erosion, the output pixel is the individual component-wise minimum of the corresponding R,G, B, A values in the input image kernel rectangle.