diff options
Diffstat (limited to 'gdk-pixbuf/pixops/pixops.c')
| -rw-r--r-- | gdk-pixbuf/pixops/pixops.c | 66 |
1 files changed, 52 insertions, 14 deletions
diff --git a/gdk-pixbuf/pixops/pixops.c b/gdk-pixbuf/pixops/pixops.c index 00652d5c6..ae0ff5ee7 100644 --- a/gdk-pixbuf/pixops/pixops.c +++ b/gdk-pixbuf/pixops/pixops.c @@ -177,10 +177,24 @@ pixops_composite_nearest (guchar *dest_buf, if (dest_has_alpha) { - dest[0] = (a0 * src[0] + (0xff - a0) * dest[0]) / 0xff; - dest[1] = (a0 * src[1] + (0xff - a0) * dest[1]) / 0xff; - dest[2] = (a0 * src[2] + (0xff - a0) * dest[2]) / 0xff; - dest[3] = (0xff * a0 + (0xff - a0) * dest[3]) / 0xff; + unsigned int w0 = 0xff * a0; + unsigned int w1 = (0xff - a0) * dest[3]; + unsigned int w = w0 + w1; + + if (w != 0) + { + dest[0] = (w0 * src[0] + w1 * dest[0]) / w; + dest[1] = (w0 * src[1] + w1 * dest[1]) / w; + dest[2] = (w0 * src[2] + w1 * dest[2]) / w; + dest[3] = w / 0xff; + } + else + { + dest[0] = 0; + dest[1] = 0; + dest[2] = 0; + dest[3] = 0; + } } else { @@ -296,12 +310,24 @@ composite_pixel (guchar *dest, int dest_x, int dest_channels, int dest_has_alpha { if (dest_has_alpha) { - unsigned int w = (0xff0000 - a) * dest[3]; + unsigned int w0 = a - (a >> 8); + unsigned int w1 = ((0xff0000 - a) >> 8) * dest[3]; + unsigned int w = w0 + w1; - dest[0] = (r + (0xff0000 - a) * dest[0]) / 0xff0000; - dest[1] = (g + (0xff0000 - a) * dest[1]) / 0xff0000; - dest[2] = (b + (0xff0000 - a) * dest[2]) / 0xff0000; - dest[3] = (0xff * a + (0xff0000 - a) * dest[3]) / 0xff0000; + if (w != 0) + { + dest[0] = (r - (r >> 8) + w1 * dest[0]) / w; + dest[1] = (g - (g >> 8) + w1 * dest[1]) / w; + dest[2] = (b - (b >> 8) + w1 * dest[2]) / w; + dest[3] = w / 0xff00; + } + else + { + dest[0] = 0; + dest[1] = 0; + dest[2] = 0; + dest[3] = 0; + } } else { @@ -354,12 +380,24 @@ composite_line (int *weights, int n_x, int n_y, if (dest_has_alpha) { - unsigned int w = (0xff0000 - a) * dest[3]; + unsigned int w0 = a - (a >> 8); + unsigned int w1 = ((0xff0000 - a) >> 8) * dest[3]; + unsigned int w = w0 + w1; - dest[0] = (r + (0xff0000 - a) * dest[0]) / 0xff0000; - dest[1] = (g + (0xff0000 - a) * dest[1]) / 0xff0000; - dest[2] = (b + (0xff0000 - a) * dest[2]) / 0xff0000; - dest[3] = (0xff * a + (0xff0000 - a) * dest[3]) / 0xff0000; + if (w != 0) + { + dest[0] = (r - (r >> 8) + w1 * dest[0]) / w; + dest[1] = (g - (g >> 8) + w1 * dest[1]) / w; + dest[2] = (b - (b >> 8) + w1 * dest[2]) / w; + dest[3] = w / 0xff00; + } + else + { + dest[0] = 0; + dest[1] = 0; + dest[2] = 0; + dest[3] = 0; + } } else { |