Merge branch 'NewClipping'

13 files changed, 269 insertions, 201 deletions

diff --git a/src/GraphicObjects/Border.cs b/src/GraphicObjects/Border.cs
index 58ccff33..7011690e 100644
--- a/src/GraphicObjects/Border.cs
+++ b/src/GraphicObjects/Border.cs
@@ -62,6 +62,15 @@ namespace Crow
 				CairoHelpers.CairoRectangle(gr, rBack, CornerRadius);
 				gr.Stroke ();
 			}
+
+			gr.Save ();
+			//clip to client zone
+			CairoHelpers.CairoRectangle (gr, ClientRectangle, CornerRadius);
+			gr.Clip ();
+
+			if (child != null)
+				child.Paint (ref gr);
+			gr.Restore ();
 		}		
 		#endregion
 	}
diff --git a/src/GraphicObjects/GraphicObject.cs b/src/GraphicObjects/GraphicObject.cs
index 14516dba..24fd852a 100644
--- a/src/GraphicObjects/GraphicObject.cs
+++ b/src/GraphicObjects/GraphicObject.cs
@@ -31,6 +31,9 @@ namespace Crow
 		internal List<Binding> Bindings = new List<Binding> ();
 		internal int layoutingTries = 0;
 
+		Rectangles clipping = new Rectangles();
+		public Rectangles Clipping { get { return clipping; }}
+
 		#region IValueChange implementation
 		public event EventHandler<ValueChangeEventArgs> ValueChanged;
 		public virtual void NotifyValueChanged(string MemberName, object _value)
@@ -121,15 +124,7 @@ namespace Crow
 		[XmlIgnore]public ILayoutable Parent { 
 			get { return _parent; }
 			set {
-//				if (_parent == value)
-//					return;
-//				if (_parent != null)
-//					ClearBinding ();
-//				
 				_parent = value;
-//
-//				if (DataSource != null)
-//					ResolveBindings ();
 			}
 		}
 
@@ -149,21 +144,19 @@ namespace Crow
 			get { return Parent == null ? null : Parent.HostContainer; }
 		}
 		public virtual Rectangle ContextCoordinates(Rectangle r){
-			return
-				Parent.ContextCoordinates (r);// + ClientRectangle.Position;
+			GraphicObject go = Parent as GraphicObject;
+			if (go == null)
+				return r + Parent.ClientRectangle.Position;
+			return go.CacheEnabled ?
+				r + Parent.ClientRectangle.Position : 
+				Parent.ContextCoordinates (r);
 		}			
 		public virtual Rectangle ScreenCoordinates (Rectangle r){
 			return 
 				Parent.ScreenCoordinates(r) + Parent.getSlot().Position + Parent.ClientRectangle.Position;
 		}
-		public virtual Rectangle getSlot()
-		{
-			return Slot;
-		}
-		public virtual Rectangle getBounds()
-		{
-			return Bounds;
-		}
+		public virtual Rectangle getSlot() => Slot;
+		public virtual Rectangle getBounds() => Bounds;
 		#endregion
 
 		#region EVENT HANDLERS
@@ -478,14 +471,21 @@ namespace Crow
 		public virtual bool Contains(GraphicObject goToFind){
 			return false;
 		}
-
-		public virtual void registerClipRect()
-		{
-			HostContainer.redrawClip.AddRectangle (ScreenCoordinates(Slot));
+		public virtual void RegisterClip(Rectangle clip){			
+			if (CacheEnabled && bmp != null)
+				Clipping.AddRectangle (clip + ClientRectangle.Position);
+			Parent.RegisterClip (clip + Slot.Position + ClientRectangle.Position);
+		}
+//		public virtual void registerClipRect(Rectangle clip)
+//		{
+//			Rectangle tmp = ContextCoordinates (clip);
+//			if (CacheEnabled) {
+//			}
+			//HostContainer.redrawClip.AddRectangle (ScreenCoordinates(Slot));
 			//this clipping should take only last painted slots on each level in ancestor tree which
 			//is not the case for now.
-			HostContainer.redrawClip.AddRectangle (ScreenCoordinates(LastPaintedSlot));
-		}
+			//HostContainer.redrawClip.AddRectangle (ScreenCoordinates(LastPaintedSlot));
+		//}
 		/// <summary>
 		/// Clear chached object and add clipping region in redraw list of interface
 		/// </summary>
@@ -502,12 +502,6 @@ namespace Crow
 		{
 			if (IsQueuedForRedraw)
 				return;
-			//test if this speed up a lot to cancel clipping for an uncached group
-			Group p = Parent as Group;
-			if (p != null) {
-				if (p.bmp == null)
-					return;
-			}
 			if (HostContainer == null)
 				return;
 			HostContainer.gobjsToRedraw.Add (this);
@@ -734,9 +728,9 @@ namespace Crow
 		}
 
 		/// <summary>
-		/// Interfal drawing context creation on a cached surface limited to slot size
+		/// Internal drawing context creation on a cached surface limited to slot size
 		/// this trigger the effective drawing routine </summary>
-		protected virtual void UpdateGraphic ()
+		protected virtual void RecreateCache ()
 		{
 			int stride = 4 * Slot.Width;
 
@@ -752,17 +746,34 @@ namespace Crow
 				draw.Flush ();
 			}
 		}
+		protected virtual void UpdateCache(Context ctx){
+			Rectangle rb = Slot + Parent.ClientRectangle.Position;
+			using (ImageSurface cache = new ImageSurface (bmp, Format.Argb32, Slot.Width, Slot.Height, 4 * Slot.Width)) {
+				//					//TODO:improve equality test for basic color and Fill
+				//					if (this.Background is SolidColor) {
+				//						if ((this.Background as SolidColor).Equals (Color.Clear)) {
+				//							ctx.Save ();
+				//							ctx.Operator = Operator.Clear;
+				//							ctx.Rectangle (rb);
+				//							ctx.Fill ();
+				//							ctx.Restore ();
+				//						}
+				//					}
+				ctx.SetSourceSurface (cache, rb.X, rb.Y);
+				ctx.Paint ();
+			}
+			//Clipping.clearAndClip (ctx);
+			Clipping.Reset();
+		}
 		/// <summary> Chained painting routine on the parent context of the actual cached version
 		/// of the widget </summary>
-		public virtual void Paint (ref Context ctx, Rectangles clip = null)
+		public virtual void Paint (ref Context ctx)
 		{
 			if (!Visible)
 				return;
 
 			LastPaintedSlot = Slot;
 
-			Rectangle rb = Parent.ContextCoordinates (Slot);
-
 			if (cacheEnabled) {
 				if (Slot.Width > Interface.MaxCacheSize || Slot.Height > Interface.MaxCacheSize)
 					cacheEnabled = false;
@@ -770,28 +781,19 @@ namespace Crow
 
 			if (cacheEnabled) {
 				if (bmp == null)
-					UpdateGraphic ();
+					RecreateCache ();
 
-				using (ImageSurface source = new ImageSurface (bmp, Format.Argb32, Slot.Width, Slot.Height, 4 * Slot.Width)) {
-					//TODO:improve equality test for basic color and Fill
-					if (this.Background is SolidColor) {
-						if ((this.Background as SolidColor).Equals (Color.Clear)) {
-							ctx.Save ();
-							ctx.Operator = Operator.Clear;
-							ctx.Rectangle (rb);
-							ctx.Fill ();
-							ctx.Restore ();
-						}
-					}
-					ctx.SetSourceSurface (source, rb.X, rb.Y);
-					ctx.Paint ();
-				}
-				return;
+				UpdateCache (ctx);
+			} else {
+				Rectangle rb = Slot + Parent.ClientRectangle.Position;
+				ctx.Save ();
+
+				ctx.Translate (rb.X, rb.Y);
+
+				onDraw (ctx);
+
+				ctx.Restore ();
 			}
-			ctx.Save ();
-			ctx.Translate (rb.X, rb.Y);
-			onDraw (ctx);
-			ctx.Restore ();
 		}
 		#endregion
 
diff --git a/src/GraphicObjects/Group.cs b/src/GraphicObjects/Group.cs
index 9d9abbc6..e1e95579 100644
--- a/src/GraphicObjects/Group.cs
+++ b/src/GraphicObjects/Group.cs
@@ -204,66 +204,53 @@ namespace Crow
 				break;
 			}
 		}
-		public override Rectangle ContextCoordinates(Rectangle r){
-			return r + ClientRectangle.Position;
-		}	
 
 		protected override void onDraw (Context gr)
 		{
 			base.onDraw (gr);
 
+			gr.Save ();
+			//clip to client zone
+			CairoHelpers.CairoRectangle (gr, ClientRectangle, CornerRadius);
+			gr.Clip ();
+
 			foreach (GraphicObject g in children) {
 				g.Paint (ref gr);
 			}
+			gr.Restore ();
 		}
-
-		public override void Paint(ref Context ctx, Rectangles clip = null)
+		protected override void UpdateCache (Context ctx)
 		{
-			if ( !Visible )
-				return;
-
-			if (bmp == null)
-				UpdateGraphic ();
-			else {
-				if (clip != null)
-					clip.Rebase (this);									
-				else {
-					clip = new Rectangles ();
-					//TODO:added lately slot to empty clip,
-					//should rework this precise case causing expandable not
-					//to show image changes
-					clip.AddRectangle (ContextCoordinates (Slot.Size));
-				}
+			Rectangle rb = Slot + Parent.ClientRectangle.Position;
 
-				if (!DrawingIsValid || clip != null) {//false when 1 child has changed
-					//child having their content changed has to be repainted
-					//and those with slot intersecting clip rectangle have also to be repainted
+			using (ImageSurface cache = new ImageSurface (bmp, Format.Argb32, Slot.Width, Slot.Height, 4 * Slot.Width)) {
+				Context gr = new Context (cache);
 
-					using (ImageSurface cache =
-						      new ImageSurface (bmp, Format.Argb32, Slot.Width, Slot.Height, Slot.Width * 4)) {
-						Context gr = new Context (cache);
-						clip.clearAndClip (gr);
+				if (Clipping.count > 0) {
+					Clipping.clearAndClip (gr);
+					base.onDraw (gr);
 
-						Rectangle rBack = Slot.Size;
-						Background.SetAsSource (gr, rBack);
-						CairoHelpers.CairoRectangle(gr, rBack, CornerRadius);
-						gr.Fill ();
+					//clip to client zone
+					CairoHelpers.CairoRectangle (gr, ClientRectangle, CornerRadius);
+					gr.Clip ();
 
-						#if DEBUG_CLIP_RECTANGLE
-						clip.stroke (gr, Color.Amaranth.AdjustAlpha (0.8));
-						#endif
-						foreach (GraphicObject c in children.Where(ch=>ch.Visible)) {
-							Rectangles childClip = clip.intersectingRects (ContextCoordinates(c.Slot));
-							if (!c.DrawingIsValid || childClip.count > 0)
-								c.Paint (ref gr, childClip);//, localClip);
-						}
-
-						gr.Dispose ();
+					foreach (GraphicObject c in children) {
+						if (!c.Visible)
+							continue;
+						if (Clipping.intersect(c.Slot + ClientRectangle.Position))
+							c.Paint (ref gr);
 					}
+
+					#if DEBUG_CLIP_RECTANGLE
+					Clipping.stroke (gr, Color.Amaranth.AdjustAlpha (0.8));
+					#endif
 				}
+				gr.Dispose ();
+
+				ctx.SetSourceSurface (cache, rb.X, rb.Y);
+				ctx.Paint ();
 			}
-				
-			base.Paint (ref ctx, clip);
+			Clipping.Reset();
 		}
 		#endregion
 
diff --git a/src/GraphicObjects/IGOLibHost.cs b/src/GraphicObjects/IGOLibHost.cs
index 1c50d558..1cf6978c 100644
--- a/src/GraphicObjects/IGOLibHost.cs
+++ b/src/GraphicObjects/IGOLibHost.cs
@@ -5,7 +5,6 @@ namespace Crow
 {
 	public interface IGOLibHost
 	{
-		Rectangles redrawClip { get; set; }
 		List<GraphicObject> gobjsToRedraw { get; }
 		GraphicObject activeWidget { get; set; }
 		GraphicObject hoverWidget { get; set; }
diff --git a/src/GraphicObjects/ILayoutable.cs b/src/GraphicObjects/ILayoutable.cs
index 54e54f03..bbf1b4a6 100644
--- a/src/GraphicObjects/ILayoutable.cs
+++ b/src/GraphicObjects/ILayoutable.cs
@@ -21,6 +21,7 @@ namespace Crow
 
 		LayoutingType RegisteredLayoutings { get; set; }
 		void RegisterForLayouting(LayoutingType layoutType);
+		void RegisterClip(Rectangle clip);
 		bool UpdateLayout(LayoutingType layoutType);
 
 
diff --git a/src/GraphicObjects/Label.cs b/src/GraphicObjects/Label.cs
index 1ce9409b..4c7e7006 100644
--- a/src/GraphicObjects/Label.cs
+++ b/src/GraphicObjects/Label.cs
@@ -597,12 +597,11 @@ namespace Crow
 				SelBegin = -1;
 				SelRelease = -1;
 				SelectionInProgress = true;
+				registerForGraphicUpdate();//TODO:should put it in properties
 			}          
 
 			//done at the end to set 'hasFocus' value after testing it
 			base.onMouseDown (sender, e);
-
-			registerForGraphicUpdate();
 		}
 		public override void onMouseUp (object sender, MouseButtonEventArgs e)
 		{
diff --git a/src/GraphicObjects/PrivateContainer.cs b/src/GraphicObjects/PrivateContainer.cs
index 9f787eac..77bf655f 100644
--- a/src/GraphicObjects/PrivateContainer.cs
+++ b/src/GraphicObjects/PrivateContainer.cs
@@ -133,33 +133,77 @@ namespace Crow
 				break;
 			}
 		}
-
-		public override Rectangle ContextCoordinates (Rectangle r)
+		protected override void onDraw (Context gr)
 		{
-			return
-				Parent.ContextCoordinates(r) + Slot.Position + ClientRectangle.Position;
+			base.onDraw (gr);
+
+			gr.Save ();
+			//clip to client zone
+			CairoHelpers.CairoRectangle (gr, ClientRectangle, CornerRadius);
+			gr.Clip ();
+
+			if (child != null)
+				child.Paint (ref gr);
+			gr.Restore ();
 		}
-		public override void Paint(ref Cairo.Context ctx, Rectangles clip = null)
+		protected override void UpdateCache (Context ctx)
 		{
-			if (!Visible)//check if necessary??
-				return;
+			//ctx.Save ();
 
-			ctx.Save();
+			Rectangle rb = Slot + Parent.ClientRectangle.Position;
 
-			if (clip != null)
-				clip.clip(ctx);
+			using (ImageSurface cache = new ImageSurface (bmp, Format.Argb32, Slot.Width, Slot.Height, 4 * Slot.Width)) {
+				Context gr = new Context (cache);
 
-			base.Paint(ref ctx, clip);
+				//clip to client zone
+				CairoHelpers.CairoRectangle (gr, ClientRectangle, CornerRadius);
+				gr.Clip ();
 
-			//clip to client zone
-			CairoHelpers.CairoRectangle (ctx, Parent.ContextCoordinates(ClientRectangle + Slot.Position), CornerRadius);
-			ctx.Clip();
+				if (Clipping.count > 0) {
+
+					Clipping.clearAndClip (gr);
+
+					if (child != null) {
+						
+						base.onDraw (gr);
 
-			if (child != null)
-				child.Paint(ref ctx, clip);
 
-			ctx.Restore();            
+						child.Paint (ref gr);
+					}
+				}
+					
+				gr.Dispose ();
+
+				ctx.SetSourceSurface (cache, rb.X, rb.Y);
+				ctx.Paint ();
+			}
+			Clipping.Reset();
+
+			//ctx.Restore ();
 		}
+//		public override Rectangle ContextCoordinates (Rectangle r)
+//		{
+//			return
+//				Parent.ContextCoordinates(r) + Slot.Position + ClientRectangle.Position;
+//		}
+//		public override void Paint(ref Cairo.Context ctx)
+//		{
+//			if (!Visible)//check if necessary??
+//				return;
+//
+//			ctx.Save();
+//
+//			base.Paint(ref ctx);
+//
+//			//clip to client zone
+//			CairoHelpers.CairoRectangle (ctx, Parent.ContextCoordinates(ClientRectangle + Slot.Position), CornerRadius);
+//			ctx.Clip();
+//
+//			if (child != null)
+//				child.Paint(ref ctx);
+//
+//			ctx.Restore();            
+//		}
 
 		#endregion
 
diff --git a/src/GraphicObjects/RadioButton.cs b/src/GraphicObjects/RadioButton.cs
index 141a9887..297b4c2b 100644
--- a/src/GraphicObjects/RadioButton.cs
+++ b/src/GraphicObjects/RadioButton.cs
@@ -71,6 +71,9 @@ namespace Crow
 			get { return isChecked; }
             set
             {
+				if (isChecked == value)
+					return;
+				
 				isChecked = value;
 
 				NotifyValueChanged ("IsChecked", value);
diff --git a/src/GraphicObjects/Scroller.cs b/src/GraphicObjects/Scroller.cs
index 3ac8d66c..1924aac0 100644
--- a/src/GraphicObjects/Scroller.cs
+++ b/src/GraphicObjects/Scroller.cs
@@ -100,6 +100,11 @@ namespace Crow
             : base(){}
 
 		#region GraphicObject Overrides
+		[XmlAttributeAttribute()][DefaultValue(false)]
+		public override bool CacheEnabled {
+			get { return base.CacheEnabled; }
+			set { base.CacheEnabled = value; }
+		}
 		void OnChildLayoutChanges (object sender, LayoutingEventArgs arg)
 		{
 			int maxScroll = MaximumScroll;
@@ -177,22 +182,56 @@ namespace Crow
 			savedMousePos.Y += e.YDelta;
 			base.onMouseMove (sender, new MouseMoveEventArgs(savedMousePos.X,savedMousePos.Y,e.XDelta,e.YDelta));
 		}
-		#endregion
-
-		public override Rectangle ContextCoordinates (Rectangle r)
+		public override void RegisterClip (Rectangle clip)
 		{
-			return base.ContextCoordinates (r) - new Point((int)ScrollX,(int)ScrollY);
+			base.RegisterClip (clip - new Point((int)ScrollX,(int)ScrollY));
 		}
+		#endregion
+
 		public override Rectangle ScreenCoordinates (Rectangle r)
 		{
 			return base.ScreenCoordinates (r) - new Point((int)ScrollX,(int)ScrollY);
 		}
-
-		public override void registerClipRect ()
+//		protected override void onDraw (Context gr)
+//		{
+//			gr.Save ();
+//			//gr.ResetClip ();
+//
+//			base.onDraw (gr);
+//			gr.Restore ();
+//		}
+		protected override void onDraw (Context gr)
 		{
-			HostContainer.redrawClip.AddRectangle (base.ScreenCoordinates(Slot));
+			Rectangle rBack = new Rectangle (Slot.Size);
+
+			Background.SetAsSource (gr, rBack);
+			CairoHelpers.CairoRectangle(gr,rBack, CornerRadius);
+			gr.Fill ();
+
+			gr.Save ();
+			//clip to scrolled client zone
+			CairoHelpers.CairoRectangle (gr, ClientRectangle, CornerRadius);//+ new Point((int)ScrollX,(int)ScrollY)
+			gr.Clip ();
+
+			gr.Translate (-ScrollX, -ScrollY);
+			if (child != null)
+				child.Paint (ref gr);
+			gr.Restore ();
 		}
 
+//		public override void Paint (ref Context ctx)
+//		{
+//			ctx.Save ();
+//			//ctx.ResetClip ();
+//			ctx.Translate (-ScrollX, -ScrollY);
+//			base.Paint (ref ctx);
+//			ctx.Restore ();
+//		}
+//		public override void registerClipRect ()
+//		{
+//			HostContainer.redrawClip.AddRectangle (base.ScreenCoordinates(Slot));
+//		}
+
 
     }
 }
diff --git a/src/GraphicObjects/TemplatedControl.cs b/src/GraphicObjects/TemplatedControl.cs
index 9dacd466..50199f7a 100644
--- a/src/GraphicObjects/TemplatedControl.cs
+++ b/src/GraphicObjects/TemplatedControl.cs
@@ -93,11 +93,6 @@ namespace Crow
 					NotifyValueChanged ("TemplatedHeight", 0);
 			}
 		}
-
-		protected override void loadDefaultValues ()
-		{			
-			base.loadDefaultValues ();
-		}
 		public override GraphicObject FindByName (string nameToFind)
 		{
 			//prevent name searching in template
diff --git a/src/GraphicObjects/Window.cs b/src/GraphicObjects/Window.cs
index d98d296c..726f858a 100644
--- a/src/GraphicObjects/Window.cs
+++ b/src/GraphicObjects/Window.cs
@@ -89,7 +89,7 @@ namespace Crow
 				if (!HasFocus)
 					return;
 				
-				otkgw.redrawClip.AddRectangle (this.ScreenCoordinates(this.Slot));
+				//otkgw.redrawClip.AddRectangle (this.ScreenCoordinates(this.Slot));
 
 				int currentLeft = this.Left;
 				int currentTop = this.Top;
diff --git a/src/OpenTKGameWindow.cs b/src/OpenTKGameWindow.cs
index 16362c6c..00035390 100644
--- a/src/OpenTKGameWindow.cs
+++ b/src/OpenTKGameWindow.cs
@@ -54,7 +54,7 @@ namespace Crow
 		List<GraphicObject> _gobjsToRedraw = new List<GraphicObject>();
 
 		#region IGOLibHost implementation
-		public Rectangles redrawClip {
+		public Rectangles clipping {
 			get {
 				return _redrawClip;
 			}
@@ -90,7 +90,7 @@ namespace Crow
 			{
 				GraphicObjects.Remove(g);
 				GraphicObjects.Insert(0, g);
-				g.registerClipRect ();
+				//g.registerClipRect ();
 			}
 		}
 		public void Quit ()
@@ -181,7 +181,7 @@ namespace Crow
 			shader.ProjectionMatrix = Matrix4.CreateOrthographicOffCenter 
 				(0, ClientRectangle.Width, ClientRectangle.Height, 0, 0, 1);			
 
-			redrawClip.AddRectangle (ClientRectangle);
+			clipping.AddRectangle (ClientRectangle);
 		}
 		void createOpenGLSurface()
 		{
@@ -253,71 +253,67 @@ namespace Crow
 			updateTime.Restart ();			
 			#endif
 
-			using (surf = new ImageSurface (bmp, Format.Argb32, ClientRectangle.Width, ClientRectangle.Height, ClientRectangle.Width * 4)) {
-				using (ctx = new Context (surf)){
+			GraphicObject[] invGOList = new GraphicObject[GraphicObjects.Count];
+			GraphicObjects.CopyTo (invGOList, 0);
+			invGOList = invGOList.Reverse ().ToArray ();
 
-					GraphicObject[] invGOList = new GraphicObject[GraphicObjects.Count];
-					GraphicObjects.CopyTo (invGOList, 0);
-					invGOList = invGOList.Reverse ().ToArray ();
+			#if MEASURE_TIME
+			layoutTime.Start ();
+			#endif
+			//Debug.WriteLine ("======= Layouting queue start =======");
 
-					#if MEASURE_TIME
-					layoutTime.Start ();
-					#endif
-					//Debug.WriteLine ("======= Layouting queue start =======");
+			while (Interface.LayoutingQueue.Count > 0) {
+				LayoutingQueueItem lqi = Interface.LayoutingQueue.Dequeue ();
+				lqi.ProcessLayouting ();
+			}
 
-					while (Interface.LayoutingQueue.Count > 0) {
-						LayoutingQueueItem lqi = Interface.LayoutingQueue.Dequeue ();
-						lqi.ProcessLayouting ();
-					}
+			#if MEASURE_TIME
+			layoutTime.Stop ();
+			#endif
 
-					#if MEASURE_TIME
-					layoutTime.Stop ();
-					#endif
+			//Debug.WriteLine ("otd:" + gobjsToRedraw.Count.ToString () + "-");
+			//final redraw clips should be added only when layout is completed among parents,
+			//that's why it take place in a second pass
+			GraphicObject[] gotr = new GraphicObject[gobjsToRedraw.Count];
+			gobjsToRedraw.CopyTo (gotr);
+			gobjsToRedraw.Clear ();
+			foreach (GraphicObject p in gotr) {
+				p.IsQueuedForRedraw = false;
+				p.Parent.RegisterClip (p.LastPaintedSlot);
+				p.Parent.RegisterClip (p.getSlot());
+			}
 
-					//Debug.WriteLine ("otd:" + gobjsToRedraw.Count.ToString () + "-");
-					//final redraw clips should be added only when layout is completed among parents,
-					//that's why it take place in a second pass
-					GraphicObject[] gotr = new GraphicObject[gobjsToRedraw.Count];
-					gobjsToRedraw.CopyTo (gotr);
-					gobjsToRedraw.Clear ();
-					foreach (GraphicObject p in gotr) {
-						p.IsQueuedForRedraw = false;
-						p.registerClipRect ();
-					}
+			#if MEASURE_TIME
+			updateTime.Stop ();
+			drawingTime.Start ();
+			#endif
 
-					#if MEASURE_TIME
-					updateTime.Stop ();
-					drawingTime.Start ();
-					#endif
+			using (surf = new ImageSurface (bmp, Format.Argb32, ClientRectangle.Width, ClientRectangle.Height, ClientRectangle.Width * 4)) {
+				using (ctx = new Context (surf)){
 
-					lock (redrawClip) {
-						if (redrawClip.count > 0) {
-							#if DEBUG_CLIP_RECTANGLE
-						redrawClip.stroke (ctx, new Color(1.0,0,0,0.3));
-							#endif
-							redrawClip.clearAndClip (ctx);
 
-							//Link.draw (ctx);
-							foreach (GraphicObject p in invGOList) {
-								if (p.Visible) {
+					if (clipping.count > 0) {
+						//Link.draw (ctx);
+						clipping.clearAndClip(ctx);
 
-									ctx.Save ();
-									if (redrawClip.count > 0) {
-										Rectangles clip = redrawClip.intersectingRects (p.Slot);
+						foreach (GraphicObject p in invGOList) {
+							if (!p.Visible)
+								continue;
 
-										if (clip.count > 0)
-											p.Paint (ref ctx, clip);
-									}
-									ctx.Restore ();
-								}
-							}
-							ctx.ResetClip ();
-							#if DEBUG_CLIP_RECTANGLE
-						redrawClip.stroke (ctx, Color.Red.AdjustAlpha(0.1));
-							#endif
-							redrawClip.Reset ();
+							ctx.Save ();
+
+							p.Paint (ref ctx);
+						
+							ctx.Restore ();
 						}
+
+						#if DEBUG_CLIP_RECTANGLE
+						clipping.stroke (ctx, Color.Red.AdjustAlpha(0.5));
+						#endif
+
+						clipping.Reset ();
 					}
+
 					#if MEASURE_TIME
 					drawingTime.Stop ();
 					#endif
@@ -549,6 +545,9 @@ namespace Crow
         #endregion
 
 		#region ILayoutable implementation
+		public void RegisterClip(Rectangle r){
+			clipping.AddRectangle (r);
+		}
 		public int LayoutingTries {
 			get { throw new NotImplementedException (); }
 			set { throw new NotImplementedException (); }
@@ -559,17 +558,13 @@ namespace Crow
 		}
 		public void RegisterForLayouting (LayoutingType layoutType) { throw new NotImplementedException (); }
 		public bool UpdateLayout (LayoutingType layoutType) { throw new NotImplementedException (); }
-		public Rectangle ContextCoordinates (Rectangle r)
-		{
-			return r;
-		}
+		public Rectangle ContextCoordinates (Rectangle r) => r;
 		public Rectangle ScreenCoordinates (Rectangle r) => r;
 
 		public ILayoutable Parent {
 			get { return null; }
 			set { throw new NotImplementedException (); }
 		}
-
 		public ILayoutable LogicalParent {
 			get { return null; }
 			set { throw new NotImplementedException (); }
@@ -581,15 +576,8 @@ namespace Crow
 		public IGOLibHost HostContainer {
 			get { return this; }
 		}
-
-		public Rectangle getSlot ()
-		{
-			return ClientRectangle;
-		}
-		public Rectangle getBounds ()//redundant but fill ILayoutable implementation
-		{
-			return ClientRectangle;
-		}			
+		public Rectangle getSlot () => ClientRectangle;
+		public Rectangle getBounds () => ClientRectangle;
 		#endregion
     }
 }
\ No newline at end of file
diff --git a/src/Rectangles.cs b/src/Rectangles.cs
index dbb4118b..c507b2ba 100644
--- a/src/Rectangles.cs
+++ b/src/Rectangles.cs
@@ -147,6 +147,8 @@ namespace Crow
 		}
         public void clearAndClip(Context ctx)
         {
+			if (list.Count == 0)
+				return;
             foreach (Rectangle r in list)
                 ctx.Rectangle(r);