gegl r2711 - in trunk: . gegl/operation

[ok svn gnome org]

Author: ok
Date: Sun Nov  9 15:58:49 2008
New Revision: 2711
URL: http://svn.gnome.org/viewvc/gegl?rev=2711&view=rev

Log:
* gegl/operation/gegl-operation-context.c: (emptybuf),
(gegl_operation_context_get_target): keep an 0x0 sized buffer around
that is shared by all needs for such a buffer to be passed as a dummy
token between nodes.


Modified:
   trunk/ChangeLog
   trunk/gegl/operation/gegl-operation-context.c

Modified: trunk/gegl/operation/gegl-operation-context.c
==============================================================================
--- trunk/gegl/operation/gegl-operation-context.c	(original)
+++ trunk/gegl/operation/gegl-operation-context.c	Sun Nov  9 15:58:49 2008
@@ -323,6 +323,20 @@
   return input;
 }
 
+static GeglBuffer *emptybuf (void)
+{
+  static GeglBuffer *empty = NULL; /* we leak this single empty buffer,
+                                      avoiding having to create it weighs
+                                      up the penalty.
+                                    */
+  if (!empty)
+    {
+      GeglRectangle rect={0,0,0,0};
+      empty = gegl_buffer_new (&empty, babl_format ("RGBA float"));
+    }
+  return empty;
+}
+
 GeglBuffer *
 gegl_operation_context_get_target (GeglOperationContext *context,
                                    const gchar          *padname)
@@ -350,12 +364,17 @@
 
   result = &context->result_rect;
 
-  if (node->dont_cache == FALSE &&
+  if (result->width == 0 ||
+      result->height == 0)
+    {
+      output = g_object_ref (emptybuf());
+    }
+  else if (node->dont_cache == FALSE &&
       ! GEGL_OPERATION_CLASS (G_OBJECT_GET_CLASS (operation))->no_cache)
     {
-          GeglBuffer    *cache;
-          cache = GEGL_BUFFER (gegl_node_get_cache (node));
-          output = gegl_buffer_create_sub_buffer (cache, result);
+      GeglBuffer    *cache;
+      cache = GEGL_BUFFER (gegl_node_get_cache (node));
+      output = gegl_buffer_create_sub_buffer (cache, result);
     }
   else
     {