Colormapped images

CI based image has the type of ci_t having CMAPBITS and its maximum value is MAXCML. The colormap itself has the type of C_MAP, which is a structure containing some control parameters and the primary color arrays pc_t ct[3][MAXCML], where index 0 is red, 1 is green and 2 is blue.

Grayscale images can be represened by colormap based image and in that case, the image type should be mapg_t. B&W images are just sepcial cases of grayscale images with 2 entries in the colormap.