virtual Fill:: and Outline:: methods so that Canvas::Items that cache image renderings of themselves can invalidate those caches when colors etc. change; add Item::{begin,end}_visual_change() so that we can notify the canvas more efficiently when *only* visual properties have changed and not the bounding box (probably needs to be used more widely)

libs/canvas/canvas/fill.h

@@ -30,14 +30,16 @@ class Fill : virtual public Item
 public:
 	Fill (Group *);
 
+	virtual void set_fill_color (Color);
+	virtual void set_fill (bool);
+
 	Color fill_color () const {
 		return _fill_color;
 	}
-	void set_fill_color (Color);
+
 	bool fill () const {
 		return _fill;
 	}
-	void set_fill (bool);
 	
 protected:
 	void setup_fill_context (Cairo::RefPtr<Cairo::Context>) const;

libs/canvas/canvas/item.h

@@ -168,8 +168,22 @@ public:
 
 protected:
 
+        /** To be called at the beginning of any property change that
+	 *  may alter the bounding box of this item
+	 */
 	void begin_change ();
+        /** To be called at the endof any property change that
+	 *  may alter the bounding box of this item
+	 */
 	void end_change ();
+        /** To be called at the beginning of any property change that
+	 *  does NOT alter the bounding box of this item
+	 */
+	void begin_visual_change ();
+        /** To be called at the endof any property change that
+	 *  does NOT alter the bounding box of this item
+	 */
+	void end_visual_change ();
 
 	Canvas* _canvas;
 	/** parent group; may be 0 if we are the root group or if we have been unparent()ed */

libs/canvas/canvas/outline.h

@@ -48,7 +48,7 @@ public:
 		return _outline;
 	}
 
-	void set_outline (bool);
+	virtual void set_outline (bool);
 
 #ifdef CANVAS_COMPATIBILITY
 	int& property_first_arrowhead () {

libs/canvas/canvas/wave_view.h

@@ -60,6 +60,9 @@ public:
 	void set_height (Distance);
 	void set_channel (int);
 	void set_region_start (ARDOUR::frameoffset_t);
+
+        void set_fill_color (Color);
+        void set_outline_color (Color);
 	
 	void region_resized ();
 

libs/canvas/fill.cc

@@ -39,21 +39,21 @@ Fill::Fill (Group* parent)
 void
 Fill::set_fill_color (Color color)
 {
-	begin_change ();
+	begin_visual_change ();
 	
 	_fill_color = color;
 
-	end_change ();
+	end_visual_change ();
 }
 
 void
 Fill::set_fill (bool fill)
 {
-	begin_change ();
+	begin_visual_change ();
 	
 	_fill = fill;
 
-	end_change ();
+	end_visual_change ();
 }
 
 void

libs/canvas/item.cc

@@ -295,7 +295,6 @@ Item::width () const
 	return 0;
 }
 
-/* XXX may be called even if bbox is not changing ... bit grotty */
 void
 Item::begin_change ()
 {
@@ -312,6 +311,17 @@ Item::end_change ()
 	}
 }
 
+void
+Item::begin_visual_change ()
+{
+}
+
+void
+Item::end_visual_change ()
+{
+	_canvas->item_visual_property_changed (this);
+}
+
 void
 Item::move (Duple movement)
 {

libs/canvas/outline.cc

@@ -41,11 +41,11 @@ Outline::Outline (Group* parent)
 void
 Outline::set_outline_color (Color color)
 {
-	begin_change ();
+	begin_visual_change ();
 	
 	_outline_color = color;
 
-	end_change ();
+	end_visual_change ();
 }
 
 void

libs/canvas/wave_view.cc

@@ -88,6 +88,20 @@ WaveView::handle_visual_property_change ()
 	}
 }
 
+void
+WaveView::set_fill_color (Color c)
+{
+	invalidate_image_cache ();
+	Fill::set_fill_color (c);
+}
+
+void
+WaveView::set_outline_color (Color c)
+{
+	invalidate_image_cache ();
+	Outline::set_outline_color (c);
+}
+
 void
 WaveView::set_samples_per_pixel (double samples_per_pixel)
 {
@@ -475,7 +489,7 @@ WaveView::CacheEntry::image ()
 			double stops[3];
 			
 			double r, g, b, a;
-			
+
 			if (_wave_view->_shape == Rectified) {
 				stops[0] = 0.1;
 				stops[0] = 0.3;