contrib_sum      2481 ext/gd/libgd/gd.c 			double alpha_factor, alpha_sum = 0.0, contrib_sum = 0.0;
contrib_sum      2523 ext/gd/libgd/gd.c 					contrib_sum += pcontribution;
contrib_sum      2542 ext/gd/libgd/gd.c 				if( contrib_sum != 0.0f) {
contrib_sum      2543 ext/gd/libgd/gd.c 					alpha_sum /= contrib_sum;