Lines Matching refs:foreground_alpha
1120 uint8_t foreground_alpha, background_alpha, output_alpha;
1124 // output_alpha = foreground_alpha + (1 - foreground_alpha) * background_alpha
1125 // output = (foreground_alpha * foreground + (1 - foreground_alpha) * background_alpha * background) / output_alpha
1129 foreground_alpha = foreground[3];
1134 foreground_alpha = foreground[1];
1139 if (foreground_alpha == 255)
1142 if (foreground_alpha == 0) {
1147 output_alpha = foreground_alpha + FAST_DIV255((255 - foreground_alpha) * background_alpha);
1155 output[b] = FAST_DIV255(foreground_alpha * foreground[b] + (255 - foreground_alpha) * background[b]);
1157 output[b] = (255 * foreground_alpha * foreground[b] + (255 - foreground_alpha) * background_alpha * background[b]) / (255 * output_alpha);