This step applies only to RGBA component groups,
and is skipped if ` MAP_COLOR` is ` FALSE`.
First, each component is clamped to the range .
There is a table associated with each of the R, G, B, and A
component elements:
` PIXEL_MAP_R_TO_R` for R,
` PIXEL_MAP_G_TO_G` for G,
` PIXEL_MAP_B_TO_B` for B,
and ` PIXEL_MAP_A_TO_A` for A.
Each element is multiplied by an integer one less than
the size of the corresponding table,
and,
for each element,
an address is found by rounding this value to the nearest integer.
For each element,
the addressed value in the corresponding table replaces the element.

Sat Mar 29 02:23:21 PST 1997