getr8, getg8, getb8, getr15, getg15, getb15, getr16, getg16, getb16, getr24, getg24, getb24, getr32,

       Given  a  color  in  a  display  dependent format, these functions extract one of the red, green, or blue
       components (ranging 0-255). Example:

          int r, g, b, color_value;

          color_value = _getpixel15(screen, 100, 100);
          r = getr15(color_value);
          g = getg15(color_value);
          b = getb15(color_value);

       getr8,  getg8,  getb8,  getr15,  getg15,  getb15, getr16, getg16, getb16, getr24, getg24, getb24, getr32,
       getg32, getb32 - Extract a color component from the specified  pixel  format.  Allegro  game  programming
       library.

geta32(3alleg4), getr(3alleg4), getr_depth(3alleg4), makecol(3alleg4), set_color_depth(3alleg4)

Allegro                                           version 4.4.3                                   getr8(3alleg4)

#include<allegro.h>intgetr8(intc);intgetg8(intc);intgetb8(intc);intgetr15(intc);intgetg15(intc);intgetb15(intc);intgetr16(intc);intgetg16(intc);intgetb16(intc);intgetr24(intc);intgetg24(intc);intgetb24(intc);intgetr32(intc);intgetg32(intc);intgetb32(intc);