set_color_blender - Enables a color blender mode. Allegro game
programming library.
#include <allegro.h>
void set_color_blender(int r, int g, int b, int a);
Enables a color blender mode for combining translucent or lit truecolor
pixels. Applies only the hue and saturation of the source image to the
destination image. The luminance of the destination image is not
affected.
set_trans_blender(3alleg), drawing_mode(3alleg)