contrib_sum      2479 ext/gd/libgd/gd.c 			double alpha_factor, alpha_sum = 0.0, contrib_sum = 0.0;
contrib_sum      2521 ext/gd/libgd/gd.c 					contrib_sum += pcontribution;
contrib_sum      2540 ext/gd/libgd/gd.c 				if( contrib_sum != 0.0f) {
contrib_sum      2541 ext/gd/libgd/gd.c 					alpha_sum /= contrib_sum;