Fl_Color fl_gray_ramp(int i)
Returs a gray color. Returns black for zero, returns white for
FL_NUM_GRAY (which is 24) minus 1. To get the closest to an
8-bit gray value 'I' use
fl_gray_ramp(I*FL_NUM_GRAY/256)
Fl_Color fl_color_cube(int r, int g, int b)
Returns a color out of the color cube.
r must be in the range 0 to FL_NUM_RED (5) minus 1.
g must be in the range 0 to FL_NUM_GREEN (8) minus 1.
b must be in the range 0 to FL_NUM_BLUE (5) minus 1.
To get the closest color to a 8-bit set of R,G,B values use
fl_color_cube(R*FL_NUM_RED/256, G*FL_NUM_GREEN/256,
B*FL_NUM_BLUE/256);