Simplify pixman_compute_composite_region32()

- It is not necessary to initialize the region before the call.

- Move all the pixman_region32_fini() calls to one place.

- Factor out the source clipping code.

1 files changed, 47 insertions, 53 deletions

diff --git a/pixman/pixman.c b/pixman/pixman.c
index 10e25d81..27eefbb0 100644
--- a/pixman/pixman.c
+++ b/pixman/pixman.c
@@ -241,10 +241,10 @@ clip_general_image (pixman_region32_t * region,
 }
 
 static inline pixman_bool_t
-clip_source_image (pixman_region32_t * region,
-                   pixman_image_t *    image,
-                   int                 dx,
-                   int                 dy)
+do_clip_source_image (pixman_region32_t * region,
+		      pixman_image_t *    image,
+		      int                 dx,
+		      int                 dy)
 {
     /* Source clips are ignored, unless they are explicitly turned on
      * and the clip in question was set by an X client. (Because if
@@ -259,6 +259,32 @@ clip_source_image (pixman_region32_t * region,
                                dx, dy);
 }
 
+static pixman_bool_t
+clip_source_image (pixman_region32_t *region,
+		   pixman_image_t    *image,
+		   int                dx,
+		   int                dy)
+{
+    if (!image->common.clip_sources)
+	return TRUE;
+
+    if (image->common.have_clip_region)
+    {
+	if (!do_clip_source_image (region, image, dx, dy))
+	    return FALSE;
+    }
+    if (image->common.alpha_map && image->common.alpha_map->common.have_clip_region)
+    {
+	if (!do_clip_source_image (region, (pixman_image_t *)image->common.alpha_map,
+				   dx + image->common.alpha_origin_x,
+				   dy + image->common.alpha_origin_y))
+	{
+	    return FALSE;
+	}
+    }
+    return TRUE;
+}
+
 /*
  * returns FALSE if the final region is empty.  Indistinguishable from
  * an allocation failure, but rendering ignores those anyways.
@@ -293,17 +319,22 @@ pixman_compute_composite_region32 (pixman_region32_t * region,
     if (region->extents.x1 >= region->extents.x2 ||
         region->extents.y1 >= region->extents.y2)
     {
-	pixman_region32_init (region);
-	return FALSE;
+	goto out_fini;
     }
 
+    /* clip against src */
+    if (!clip_source_image (region, src_image, src_x - dest_x, src_y - dest_y))
+	goto out_fini;
+
+    /* clip against mask */
+    if (mask_image && !clip_source_image (region, mask_image, mask_x - dest_x, mask_y - dest_y))
+	goto out_fini;
+
+    /* clip against dest */
     if (dst_image->common.have_clip_region)
     {
 	if (!clip_general_image (region, &dst_image->common.clip_region, 0, 0))
-	{
-	    pixman_region32_fini (region);
-	    return FALSE;
-	}
+	    goto out_fini;
     }
 
     if (dst_image->common.alpha_map && dst_image->common.alpha_map->common.have_clip_region)
@@ -312,51 +343,15 @@ pixman_compute_composite_region32 (pixman_region32_t * region,
 	                         -dst_image->common.alpha_origin_x,
 	                         -dst_image->common.alpha_origin_y))
 	{
-	    pixman_region32_fini (region);
-	    return FALSE;
-	}
-    }
-
-    /* clip against src */
-    if (src_image->common.have_clip_region)
-    {
-	if (!clip_source_image (region, src_image, dest_x - src_x, dest_y - src_y))
-	{
-	    pixman_region32_fini (region);
-	    return FALSE;
-	}
-    }
-    if (src_image->common.alpha_map && src_image->common.alpha_map->common.have_clip_region)
-    {
-	if (!clip_source_image (region, (pixman_image_t *)src_image->common.alpha_map,
-	                        dest_x - (src_x - src_image->common.alpha_origin_x),
-	                        dest_y - (src_y - src_image->common.alpha_origin_y)))
-	{
-	    pixman_region32_fini (region);
-	    return FALSE;
-	}
-    }
-    /* clip against mask */
-    if (mask_image && mask_image->common.have_clip_region)
-    {
-	if (!clip_source_image (region, mask_image, dest_x - mask_x, dest_y - mask_y))
-	{
-	    pixman_region32_fini (region);
-	    return FALSE;
-	}
-	if (mask_image->common.alpha_map && mask_image->common.alpha_map->common.have_clip_region)
-	{
-	    if (!clip_source_image (region, (pixman_image_t *)mask_image->common.alpha_map,
-	                            dest_x - (mask_x - mask_image->common.alpha_origin_x),
-	                            dest_y - (mask_y - mask_image->common.alpha_origin_y)))
-	    {
-		pixman_region32_fini (region);
-		return FALSE;
-	    }
+	    goto out_fini;
 	}
     }
 
     return TRUE;
+
+out_fini:
+    pixman_region32_fini (region);
+    return FALSE;
 }
 
 static void
@@ -570,8 +565,7 @@ do_composite (pixman_implementation_t *imp,
 	apply_workaround (dest, &dest_x, &dest_y, &dest_bits, &dest_dx, &dest_dy);
     }
 
-    pixman_region32_init (&region);
-    
+    /* Compute composite region */
     if (!pixman_compute_composite_region32 (
 	    &region, src, mask, dest,
 	    src_x, src_y, mask_x, mask_y, dest_x, dest_y, width, height))