Improve this code to allow layers like 'blur' to work.

git-svn-id: http://svn.voria.com/code@1428 1f10aa63-cdf2-0310-b900-c93c546f37ac

diff --git a/synfig-core/trunk/src/synfig/canvas.cpp b/synfig-core/trunk/src/synfig/canvas.cpp
index 270a71f..605fd26 100644 (file)
--- a/synfig-core/trunk/src/synfig/canvas.cpp
+++ b/synfig-core/trunk/src/synfig/canvas.cpp
@@ -1180,7 +1180,23 @@ synfig::optimize_layers(Time time, Context context, Canvas::Handle op_canvas, bo
 
                        // \todo: this code probably needs modification to work properly with motionblur and duplicate
                        etl::handle<Layer_Composite> composite = etl::handle<Layer_Composite>::cast_dynamic(layer);
-                       if (composite && composite->get_blend_method() == Color::BLEND_STRAIGHT)
+
+                       /* this still isn't right; the problem is that some layers
+                        * (such as circle) don't touch pixels that aren't part of
+                        * the circle, so they don't get blended correctly when using
+                        * a straight blend.  so we encapsulate the circle, and the
+                        * encapsulation layer takes care of the transparent pixels
+                        * for us.  if we do that for all layers, however, then the
+                        * distortion layers no longer work, since they have no
+                        * context to work on.  as an approximation to fixing this,
+                        * let's encapsulate only the layers which don't have the
+                        * full plane as their bounding rect.  that tends to catch
+                        * the layers we want to catch, but still isn't quite right
+                        * (consider the circle layer with 'invert' enabled, for
+                        * instance) 
+                        */
+                        if (composite && composite->get_blend_method() == Color::BLEND_STRAIGHT &&
+                               layer->get_bounding_rect() != Rect::full_plane())
                        {
                                Canvas::Handle sub_canvas(Canvas::create_inline(op_canvas));
                                sub_canvas->push_back(composite = composite->clone());