set_saturation_blender - Man Page

#include <allegro.h>

void set_saturation_blender(int r, int g, int b, int a);

Enables a saturation blender mode for combining translucent or lit  truecolor pixels. Applies the saturation of the source to the destination  image.

set_trans_blender(3), drawing_mode(3)

set_trans_blender(3).