cmap, remap - map colors
fb/cmap colormap [ input ]
fb/remap colormap [ input ]
Cmap looks up the rgb channels of the input picture file (default stan-
dard input), in the colormap, writing the resulting rgb image to stan-
dard output. That is, cmap writes on its output the result of applying
the colormap to the pixels of the input image.
Remap is approximately the inverse of cmap. Pixel values in the input
image are replaced by those that, when mapped through the input col-
ormap, come closest to reproducing the input image. The output picture
includes a copy of the colormap.
Both commands work only if the input image contains rgb channels.