[gtk+/wip/blur-2: 3/5] Add blur to box-shadow

[Andrea Cimitan <acimitan src gnome org>]

commit a66425884de2ca86b4435e103533e22c9a297ce4
Author: Andrea Cimitan <andrea cimitan canonical com>
Date:   Mon Apr 16 12:02:41 2012 +0100

    Add blur to box-shadow

 gtk/gtkshadow.c |   66 ++++++++++++++++++++++++++++++++++++++++++++++++++-----
 1 files changed, 60 insertions(+), 6 deletions(-)
---
diff --git a/gtk/gtkshadow.c b/gtk/gtkshadow.c
index 52804af..dc3ffe2 100644
--- a/gtk/gtkshadow.c
+++ b/gtk/gtkshadow.c
@@ -283,11 +283,13 @@ _gtk_text_shadow_paint_layout (GtkShadow       *shadow,
 
           cairo_get_current_point (cr, &x, &y);
 
+          /* Create a larger surface to center the blur. */
           surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
                                                 ink_rect.width + bradius * 2 + padding * 2,
                                                 ink_rect.height + bradius * 2 + padding * 2);
           cr_surface = cairo_create (surface); 
 
+          /* Center the rendering. */
           cairo_translate (cr_surface,
                            - ink_rect.x + bradius + padding,
                            - ink_rect.y + bradius + padding);
@@ -316,7 +318,7 @@ _gtk_text_shadow_paint_layout (GtkShadow       *shadow,
 
       cairo_rel_move_to (cr, -element->hoffset, -element->voffset);
       cairo_restore (cr);
-  }
+    }
 }
 
 void
@@ -398,12 +400,64 @@ _gtk_box_shadow_render (GtkShadow           *shadow,
                                element->spread, element->spread,
                                element->spread, element->spread);
 
-      _gtk_rounded_box_path (&box, cr);
-      _gtk_rounded_box_clip_path (padding_box, cr);
+      if (element->radius > 0)
+        {
+          cairo_t *cr_surface;
+          cairo_surface_t *surface;
+          gint bradius;
+          gdouble x, y, width, height;
+
+          bradius = element->radius;
 
-      gdk_cairo_set_source_rgba (cr, &element->color);
-      cairo_fill (cr);
-  }
+          cairo_get_current_point (cr, &x, &y);
+
+          /* Take the bigger box to create the surface. */
+          width = MAX (padding_box->box.width, box.box.width);
+          height = MAX (padding_box->box.height, box.box.height);
+
+          /* Create a larger surface to center the blur. */
+          surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
+                                                width + bradius * 2,
+                                                height + bradius * 2);
+          cr_surface = cairo_create (surface); 
+
+          /* Center the rendering. */
+          cairo_translate (cr_surface,
+                           bradius,
+                           bradius);
+
+          /* Create the path on the surface to blur. */
+            _gtk_rounded_box_path (padding_box, cr_surface);
+          cairo_clip (cr_surface);
+
+          _gtk_rounded_box_path (&box, cr_surface);
+          _gtk_rounded_box_clip_path (padding_box, cr_surface);
+
+          cairo_set_fill_rule (cr_surface, CAIRO_FILL_RULE_EVEN_ODD);
+          gdk_cairo_set_source_rgba (cr_surface, &element->color);
+          cairo_fill (cr_surface);
+
+          /* Blur the surface. */
+          _gtk_cairo_blur_surface (surface, bradius);
+
+          /* Paint the blurred surface to cr. */
+          cairo_set_source_surface (cr, surface,
+                                    x - bradius,
+                                    y - bradius); 
+          cairo_paint (cr);
+
+          cairo_destroy (cr_surface);
+          cairo_surface_destroy (surface); 
+        }
+      else
+        {
+          _gtk_rounded_box_path (&box, cr);
+          _gtk_rounded_box_clip_path (padding_box, cr);
+
+          gdk_cairo_set_source_rgba (cr, &element->color);
+          cairo_fill (cr);
+        }
+    }
 
   cairo_restore (cr);
 }