rendernodes: Fix unconditionally impossible diffs

Some of the _diff implementations did a whole bunch of work just to
throw it away afterwards and invalidate the entire union of the two
render nodes, most notably the two clip nodes. Fix this to only call
gsk_render_node_diff_impossible if the previous if-condition is FALSE
and not always.

diff --git a/gsk/gskrendernodeimpl.c b/gsk/gskrendernodeimpl.c
index 2777c4ca741cd7ab0c552bed2ad1c8ad0e0b6863..8b704aeddaf668b24c121c6abe7283266e40fb37 100644 (file)
--- a/gsk/gskrendernodeimpl.c
+++ b/gsk/gskrendernodeimpl.c
@@ -3565,7 +3565,7 @@ gsk_clip_node_diff (GskRenderNode  *node1,
     {
       cairo_region_t *sub;
       cairo_rectangle_int_t clip_rect;
-      
+
       sub = cairo_region_create();
       gsk_render_node_diff (self1->child, self2->child, sub);
       rectangle_init_from_graphene (&clip_rect, &self1->clip);
@@ -3573,8 +3573,10 @@ gsk_clip_node_diff (GskRenderNode  *node1,
       cairo_region_union (region, sub);
       cairo_region_destroy (sub);
     }
-
-  gsk_render_node_diff_impossible (node1, node2, region);
+  else
+    {
+      gsk_render_node_diff_impossible (node1, node2, region);
+    }
 }
 
 #define GSK_CLIP_NODE_VARIANT_TYPE "(dddduv)"
@@ -3737,7 +3739,7 @@ gsk_rounded_clip_node_diff (GskRenderNode  *node1,
     {
       cairo_region_t *sub;
       cairo_rectangle_int_t clip_rect;
-      
+
       sub = cairo_region_create();
       gsk_render_node_diff (self1->child, self2->child, sub);
       rectangle_init_from_graphene (&clip_rect, &self1->clip.bounds);
@@ -3745,8 +3747,10 @@ gsk_rounded_clip_node_diff (GskRenderNode  *node1,
       cairo_region_union (region, sub);
       cairo_region_destroy (sub);
     }
-
-  gsk_render_node_diff_impossible (node1, node2, region);
+  else
+    {
+      gsk_render_node_diff_impossible (node1, node2, region);
+    }
 }
 
 #define GSK_ROUNDED_CLIP_NODE_VARIANT_TYPE "(dddddddddddduv)"
@@ -4262,8 +4266,10 @@ gsk_blend_node_diff (GskRenderNode  *node1,
       gsk_render_node_diff (self1->top, self2->top, region);
       gsk_render_node_diff (self1->bottom, self2->bottom, region);
     }
-
-  gsk_render_node_diff_impossible (node1, node2, region);
+  else
+    {
+      gsk_render_node_diff_impossible (node1, node2, region);
+    }
 }
 
 #define GSK_BLEND_NODE_VARIANT_TYPE "(uvuvu)"