Fix bugs with alpha maps

The alpha channel from the alpha map must be inserted as the new alpha
channel when a scanline is fetched from an image. Previously the alpha
map would overwrite the buffer instead. This wasn't caught be the
alpha map test because it would only verify that the resulting alpha
channel was correct, and not pay attention to incorrect color
channels.

1 files changed, 42 insertions, 11 deletions

diff --git a/pixman/pixman-bits-image.c b/pixman/pixman-bits-image.c
index 99c0dfe6..2f56de31 100644
--- a/pixman/pixman-bits-image.c
+++ b/pixman/pixman-bits-image.c
@@ -1294,12 +1294,27 @@ dest_get_scanline_narrow (pixman_iter_t *iter, const uint32_t *mask)
     image->bits.fetch_scanline_32 (image, x, y, width, buffer, mask);
     if (image->common.alpha_map)
     {
-	x -= image->common.alpha_origin_x;
-	y -= image->common.alpha_origin_y;
+	uint32_t *alpha;
+
+	if ((alpha = malloc (width * sizeof (uint32_t))))
+	{
+	    int i;
+
+	    x -= image->common.alpha_origin_x;
+	    y -= image->common.alpha_origin_y;
+
+	    image->common.alpha_map->fetch_scanline_32 (
+		(pixman_image_t *)image->common.alpha_map,
+		x, y, width, alpha, mask);
 
-	image->common.alpha_map->fetch_scanline_32 (
-	    (pixman_image_t *)image->common.alpha_map,
-	    x, y, width, buffer, mask);
+	    for (i = 0; i < width; ++i)
+	    {
+		buffer[i] &= ~0xff000000;
+		buffer[i] |= (alpha[i] & 0xff000000);
+	    }
+
+	    free (alpha);
+	}
     }
 
     return iter->buffer;
@@ -1312,17 +1327,33 @@ dest_get_scanline_wide (pixman_iter_t *iter, const uint32_t *mask)
     int             x      = iter->x;
     int             y      = iter->y;
     int             width  = iter->width;
-    uint32_t *	    buffer = iter->buffer;
+    uint64_t *	    buffer = (uint64_t *)iter->buffer;
 
     image->fetch_scanline_64 (
-	(pixman_image_t *)image, x, y, width, buffer, mask);
+	(pixman_image_t *)image, x, y, width, (uint32_t *)buffer, mask);
     if (image->common.alpha_map)
     {
-	x -= image->common.alpha_origin_x;
-	y -= image->common.alpha_origin_y;
+	uint64_t *alpha;
+
+	if ((alpha = malloc (width * sizeof (uint64_t))))
+	{
+	    int i;
+
+	    x -= image->common.alpha_origin_x;
+	    y -= image->common.alpha_origin_y;
 
-	image->common.alpha_map->fetch_scanline_64 (
-	    (pixman_image_t *)image->common.alpha_map, x, y, width, buffer, mask);
+	    image->common.alpha_map->fetch_scanline_64 (
+		(pixman_image_t *)image->common.alpha_map,
+		x, y, width, (uint32_t *)alpha, mask);
+
+	    for (i = 0; i < width; ++i)
+	    {
+		buffer[i] &= ~0xffff000000000000ULL;
+		buffer[i] |= (alpha[i] & 0xffff000000000000ULL);
+	    }
+
+	    free (alpha);
+	}
     }
 
     return iter->buffer;