[dia] Bug #591911 - clipping problems when rendering with alpha

[Hans Breuer <hans src gnome org>]

commit cf021c3b0c722210f2096ac14433192959ff2aa7
Author: Hans Breuer <hans breuer org>
Date:   Fri Aug 21 13:35:25 2009 +0200

    Bug #591911 - clipping problems when rendering with alpha
    
    The alpha rendering from bug #591525 made the lack of proper
    clipping very visible, before the lack of it did not show because
    drawing the same object multiple times had no accumulating effect.

 plug-ins/cairo/diacairo-interactive.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)
---
diff --git a/plug-ins/cairo/diacairo-interactive.c b/plug-ins/cairo/diacairo-interactive.c
index c83ab92..a9880a5 100644
--- a/plug-ins/cairo/diacairo-interactive.c
+++ b/plug-ins/cairo/diacairo-interactive.c
@@ -208,6 +208,11 @@ begin_render(DiaRenderer *self)
   g_return_if_fail (base_renderer->cr == NULL);
   base_renderer->cr = gdk_cairo_create(renderer->pixmap);
 
+  /* Setup clipping for this sequence of render operations */
+  /* Must be done before the scaling because the clip is in pixel coords */
+  gdk_cairo_region (base_renderer->cr, renderer->clip_region);
+  cairo_clip(base_renderer->cr); 
+
   cairo_scale (base_renderer->cr, *renderer->zoom_factor, *renderer->zoom_factor);
   cairo_translate (base_renderer->cr, -renderer->visible->left, -renderer->visible->top);
 
@@ -359,6 +364,7 @@ static void
 clip_region_clear(DiaRenderer *object)
 {
   DiaCairoInteractiveRenderer *renderer = DIA_CAIRO_INTERACTIVE_RENDERER (object);
+  DiaCairoRenderer *base_renderer = DIA_CAIRO_RENDERER (object);
 
   if (renderer->clip_region != NULL)
     gdk_region_destroy(renderer->clip_region);
@@ -373,6 +379,7 @@ clip_region_add_rect(DiaRenderer *object,
 		 Rectangle *rect)
 {
   DiaCairoInteractiveRenderer *renderer = DIA_CAIRO_INTERACTIVE_RENDERER (object);
+  DiaCairoRenderer *base_renderer = DIA_CAIRO_RENDERER (object);
   GdkRectangle clip_rect;
   int x1,y1;
   int x2,y2;