generate_optimized_palette - Generates an optimized palette for a bitmap.
Allegro game programming library.
int generate_optimized_palette(BITMAP *bmp, PALETTE pal,
const char rsvd[PAL_SIZE]);
Generates a 256-color palette suitable for making a reduced color version of the
specified truecolor image. The rsvd parameter points to a table indicating
which colors it is allowed to modify: zero for free colors which may be set to
whatever the optimiser likes, negative values for reserved colors which cannot
be used, and positive values for fixed palette entries that must not be
changed, but can be used in the optimisation.
Returns the number of different colors recognised in the provided bitmap, zero
if the bitmap is not a truecolor image or there wasn't enough memory to
perform the operation, and negative if there was any internal error in the
color reduction code.