Merge SimplerLayoutingQueue

15 files changed, 328 insertions, 272 deletions

diff --git a/src/GraphicObjects/ComboBox.cs b/src/GraphicObjects/ComboBox.cs
index ed979d75..aee7da9b 100644
--- a/src/GraphicObjects/ComboBox.cs
+++ b/src/GraphicObjects/ComboBox.cs
@@ -164,11 +164,7 @@ namespace Crow
 
 			}
 		}
-		public override void UpdateLayout (LayoutingType layoutType)
-		{
-			CheckPendingChildrenAddition ();
-			base.UpdateLayout (layoutType);
-		}
+
 		internal void CheckPendingChildrenAddition()
 		{
 			if (pendingChildrenAddition == null)
@@ -281,7 +277,7 @@ namespace Crow
 		{
 			IsPopped = false;
 		}
-		void _overlay_LayoutChanged (object sender, LayoutChangeEventArgs e)
+		void _overlay_LayoutChanged (object sender, LayoutingEventArgs e)
 		{
 			ILayoutable tc = Overlay.Parent as ILayoutable;
 			if (tc == null)
diff --git a/src/GraphicObjects/GenericStack.cs b/src/GraphicObjects/GenericStack.cs
index 92e944bb..d2338362 100644
--- a/src/GraphicObjects/GenericStack.cs
+++ b/src/GraphicObjects/GenericStack.cs
@@ -31,13 +31,13 @@ namespace Crow
 		public override T addChild<T> (T child)
 		{
 			T tmp = base.addChild (child);
-			this.RegisterForLayouting ((int)LayoutingType.PositionChildren);
+			this.RegisterForLayouting (LayoutingType.PositionChildren);
 			return tmp;
 		}
 		public override void removeChild (GraphicObject child)
 		{
 			base.removeChild (child);
-			this.RegisterForLayouting ((int)LayoutingType.PositionChildren);
+			this.RegisterForLayouting (LayoutingType.PositionChildren);
 		}
 
 		#region Public Properties
@@ -66,14 +66,18 @@ namespace Crow
 			Size tmp = new Size ();
 
 			if (Orientation == Orientation.Horizontal) {
-				foreach (GraphicObject c in Children.Where(ch=>ch.Visible)) {
+				foreach (GraphicObject c in Children) {
+					if (!c.Visible)
+						continue;					
 					tmp.Width += c.Slot.Width + Spacing;
 					tmp.Height = Math.Max (tmp.Height, Math.Max(c.Slot.Bottom, c.Slot.Height));
 				}
 				if (tmp.Width > 0)
 					tmp.Width -= Spacing;
 			} else {
-				foreach (GraphicObject c in Children.Where(ch=>ch.Visible)) {
+				foreach (GraphicObject c in Children) {
+					if (!c.Visible)
+						continue;					
 					tmp.Width = Math.Max (tmp.Width, Math.Max(c.Slot.Right, c.Slot.Width));
 					tmp.Height += c.Slot.Height + Spacing;
 				}
@@ -93,84 +97,147 @@ namespace Crow
 			#endif
 			int d = 0;
 			if (Orientation == Orientation.Horizontal) {
-				foreach (GraphicObject c in Children.Where(ch=>ch.Visible)) {
+				foreach (GraphicObject c in Children) {
+					if (!c.Visible)
+						continue;
 					c.Slot.X = d;
 					d += c.Slot.Width + Spacing;
-					c.RegisterForLayouting ((int)LayoutingType.Y);
+					c.RegisterForLayouting (LayoutingType.Y);
 				}
 			} else {
-				foreach (GraphicObject c in Children.Where(ch=>ch.Visible)) {
+				foreach (GraphicObject c in Children) {
+					if (!c.Visible)
+						continue;					
 					c.Slot.Y = d;
 					d += c.Slot.Height + Spacing;
-					c.RegisterForLayouting ((int)LayoutingType.X);
+					c.RegisterForLayouting (LayoutingType.X);
 				}
 			}
+			bmp = null;
 		}
+			
+		public override bool UpdateLayout (LayoutingType layoutType)
+        {
+			RegisteredLayoutings &= (~layoutType);
 
-		public override void RegisterForLayouting (int layoutType)
-		{			
-			if (Parent == null)
-				return;
+			LayoutingType childSizeToCheck;
+			if (Orientation == Orientation.Horizontal)
+				childSizeToCheck = LayoutingType.Width;
+			else
+				childSizeToCheck = LayoutingType.Height;
 
-			base.RegisterForLayouting (layoutType);
+			foreach (GraphicObject g in Children) {
+				if (!g.Visible)
+					continue;
+				if (g.RegisteredLayoutings.HasFlag (childSizeToCheck))
+					return false;						
+			}
 
-			if ((layoutType & (int)LayoutingType.PositionChildren) > 0)
-				Interface.LayoutingQueue.Enqueue (LayoutingType.PositionChildren, this);
-			
-		}
-		public override void UpdateLayout (LayoutingType layoutType)
-        {            
 			if (layoutType == LayoutingType.PositionChildren) {
 				//allow 1 child to have size to 0 if stack has fixed or streched size,
 				//this child will occupy remaining space
 				if (Orientation == Orientation.Horizontal) {
 					if (Width >= 0) {
-						GraphicObject[] gobjs = Children.Where (c => c.Width == 0 && c.Visible).ToArray();
-						if (gobjs.Length > 1)
-							throw new Exception ("Only one child in stack may have size to stretched");
-						else if (gobjs.Length == 1) {
-							int sz = Children.Where(ch=>ch.Visible).Except (gobjs).Sum (g => g.Slot.Width);
-							if (sz < Slot.Width) {
-								gobjs [0].Slot.Width = Slot.Width - sz - (Children.Count-1) * Spacing - 2 * Margin;
-								int idx = Children.IndexOf (gobjs [0]);
-								if (idx > 0 && idx < Children.Count - 1)
-									gobjs [0].Slot.Width -= Spacing;
-								if (gobjs [0].LastSlots.Width != gobjs [0].Slot.Width) {
-									gobjs [0].bmp = null;
-									gobjs [0].OnLayoutChanges (LayoutingType.Width);
-									gobjs [0].LastSlots.Width = gobjs [0].Slot.Width;
-								}
+						GraphicObject stretchedGO = null;
+						int tmpWidth = Slot.Width;
+						int cptChildren = 0;
+						for (int i = 0; i < Children.Count; i++) {
+							if (!Children [i].Visible)
+								continue;
+							cptChildren++;
+							if (Children [i].Width == 0) {
+								if (stretchedGO != null)
+									throw new Exception ("Only one child in stack may have size to stretched");
+								stretchedGO = Children [i];
+								if (i < Children.Count - 1)
+									tmpWidth -= Spacing;
+								continue;
+							}
+							tmpWidth -= Children[i].Slot.Width + Spacing;
+						}
+						if (stretchedGO != null) {
+							tmpWidth += (Spacing - 2 * Margin);
+							if (tmpWidth < MinimumSize.Width)
+								tmpWidth = MinimumSize.Width;
+							else if (tmpWidth > MaximumSize.Width && MaximumSize.Width > 0)
+								tmpWidth = MaximumSize.Width;
+							if (stretchedGO.LastSlots.Width != tmpWidth) {
+								stretchedGO.Slot.Width = tmpWidth;
+								stretchedGO.bmp = null;
+								stretchedGO.OnLayoutChanges (LayoutingType.Width);
+								stretchedGO.LastSlots.Width = stretchedGO.Slot.Width;
 							}
 						}
 					}					
 				} else {
 					if (Height >= 0) {
-						GraphicObject[] gobjs = Children.Where(ch=>ch.Visible).Where (c => c.Height == 0).ToArray();
-						if (gobjs.Length > 1)
-							throw new Exception ("Only one child in stack may have size to stretched");
-						else if (gobjs.Length == 1) {
-							int sz = Children.Where(ch=>ch.Visible).Except (gobjs).Sum (g => g.Slot.Height);
-							if (sz < Slot.Height) {
-								gobjs [0].Slot.Height = Slot.Height - sz- (Children.Count-1) * Spacing - 2 * Margin;
-								int idx = Children.IndexOf (gobjs [0]);
-								if (idx > 0 && idx < Children.Count - 1)
-									gobjs [0].Slot.Height -= Spacing;
-								if (gobjs [0].LastSlots.Height != gobjs [0].Slot.Height) {
-									gobjs [0].bmp = null;
-									gobjs [0].OnLayoutChanges (LayoutingType.Height);
-									gobjs [0].LastSlots.Height = gobjs [0].Slot.Height;
-								}
+						GraphicObject stretchedGO = null;
+						int tmpHeight = Slot.Height;
+						int cptChildren = 0;
+						for (int i = 0; i < Children.Count; i++) {
+							if (!Children [i].Visible)
+								continue;
+							cptChildren++;
+							if (Children [i].Height == 0) {
+								if (stretchedGO != null)
+									throw new Exception ("Only one child in stack may have size to stretched");
+								stretchedGO = Children [i];
+								if (i < Children.Count - 1)
+									tmpHeight -= Spacing;
+								continue;
+							}
+							tmpHeight -= Children[i].Slot.Height + Spacing;
+						}
+						if (stretchedGO != null) {
+							tmpHeight += (Spacing - 2 * Margin);
+							if (tmpHeight < MinimumSize.Height)
+								tmpHeight = MinimumSize.Height;
+							else if (tmpHeight > MaximumSize.Height && MaximumSize.Height > 0)
+								tmpHeight = MaximumSize.Height;
+							if (stretchedGO.LastSlots.Height != tmpHeight) {
+								stretchedGO.Slot.Height = tmpHeight;
+								stretchedGO.bmp = null;
+								stretchedGO.OnLayoutChanges (LayoutingType.Height);
+								stretchedGO.LastSlots.Height = stretchedGO.Slot.Height;
 							}
 						}
 					}
-				}				
+				}
+
 				ComputeChildrenPositions ();
+
 				//if no layouting remains in queue for item, registre for redraw
-				if (RegisteredLQINodes.Count () <= 0 && bmp==null)
+				if (RegisteredLayoutings == LayoutingType.None && bmp==null)
 					this.RegisterForRedraw ();
-			}else
-				base.UpdateLayout(layoutType);
+
+				return true;
+			}
+
+			return base.UpdateLayout(layoutType);
         }
+
+		public override void OnChildLayoutChanges (object sender, LayoutingEventArgs arg)
+		{
+			base.OnChildLayoutChanges (sender, arg);
+
+			GraphicObject g = sender as GraphicObject;
+			switch (arg.LayoutType) {
+			case LayoutingType.Width:
+				if (Orientation == Orientation.Horizontal) {
+					if (this.Bounds.Width < 0)
+						this.RegisterForLayouting (LayoutingType.Width);
+					this.RegisterForLayouting (LayoutingType.PositionChildren);
+				}
+				break;
+			case LayoutingType.Height:
+				if (Orientation == Orientation.Vertical) {
+					if (this.Bounds.Height < 0)
+						this.RegisterForLayouting (LayoutingType.Height);
+					this.RegisterForLayouting (LayoutingType.PositionChildren);
+				}
+				break;
+			}
+		}
 		#endregion
 
     
diff --git a/src/GraphicObjects/GraphicObject.cs b/src/GraphicObjects/GraphicObject.cs
index f6963cb5..88af16dd 100644
--- a/src/GraphicObjects/GraphicObject.cs
+++ b/src/GraphicObjects/GraphicObject.cs
@@ -64,6 +64,7 @@ namespace Crow
 		#endregion
 
 		#region private fields
+		LayoutingType registeredLayoutings = LayoutingType.None;
 		ILayoutable _parent;
 		string _name = "unamed";
 		Fill _background = Color.Transparent;
@@ -111,11 +112,7 @@ namespace Crow
 		#endregion
 
 		#region ILayoutable
-		/// <summary>
-		/// Keep ref's of LQI in queue per GraphicObject, to prevent searching in
-		/// the double linked list which would be very slow.
-		/// </summary>
-		public List<LinkedListNode<LayoutingQueueItem>> RegisteredLQINodes { get; } = new List<LinkedListNode<LayoutingQueueItem>>();
+		[XmlIgnore]public LayoutingType RegisteredLayoutings { get { return registeredLayoutings; } set { registeredLayoutings = value; } }
 		//TODO: it would save the recurent cost of a cast in event bubbling if parent type was GraphicObject
 		//		or we could add to the interface the mouse events
 		/// <summary>
@@ -177,7 +174,7 @@ namespace Crow
 		public event EventHandler<KeyboardKeyEventArgs> KeyUp;
 		public event EventHandler Focused;
 		public event EventHandler Unfocused;
-		public event EventHandler<LayoutChangeEventArgs> LayoutChanged;
+		public event EventHandler<LayoutingEventArgs> LayoutChanged;
 		#endregion
 
 		#region public properties
@@ -222,7 +219,7 @@ namespace Crow
 
 				Bounds.X = value;
 				NotifyValueChanged ("Left", Bounds.X);
-				this.RegisterForLayouting ((int)LayoutingType.X);
+				this.RegisterForLayouting (LayoutingType.X);
 			}
 		}
 		[XmlAttributeAttribute()][DefaultValue(0)]
@@ -234,7 +231,7 @@ namespace Crow
 
 				Bounds.Y = value;
 				NotifyValueChanged ("Top", Bounds.Y);
-				this.RegisterForLayouting ((int)LayoutingType.Y);
+				this.RegisterForLayouting (LayoutingType.Y);
 			}
 		}
 		[XmlAttributeAttribute()][DefaultValue(0)]
@@ -246,7 +243,7 @@ namespace Crow
 
 				Bounds.Width = value;
 				NotifyValueChanged ("Width", Bounds.Width);
-				this.RegisterForLayouting ((int)LayoutingType.Width);
+				this.RegisterForLayouting (LayoutingType.Width);
 			}
 		}
 		[XmlAttributeAttribute()][DefaultValue(0)]
@@ -258,7 +255,7 @@ namespace Crow
 
 				Bounds.Height = value;
 				NotifyValueChanged ("Height", Bounds.Height);
-				this.RegisterForLayouting ((int)LayoutingType.Height);
+				this.RegisterForLayouting (LayoutingType.Height);
 			}
 		}
 		[XmlAttributeAttribute()][DefaultValue(false)]
@@ -374,7 +371,7 @@ namespace Crow
 				if (this.Contains (HostContainer.hoverWidget))
 					HostContainer.hoverWidget = null;
 				if (Parent is GenericStack)
-					Parent.RegisterForLayouting ((int)LayoutingType.Sizing | (int)LayoutingType.PositionChildren);
+					Parent.RegisterForLayouting (LayoutingType.Sizing | LayoutingType.PositionChildren);
 
 				NotifyValueChanged ("Visible", _isVisible);
 			}
@@ -389,7 +386,7 @@ namespace Crow
 			get { return _maximumSize; }
 			set { _maximumSize = value; }
 		}
-		[XmlAttributeAttribute()][DefaultValue("0;0")]
+		[XmlAttributeAttribute()][DefaultValue("1;1")]
 		public virtual Size MinimumSize {
 			get { return _minimumSize; }
 			set { _minimumSize = value; }
@@ -472,7 +469,7 @@ namespace Crow
 		public virtual void registerClipRect()
 		{
 			HostContainer.redrawClip.AddRectangle (ScreenCoordinates(Slot));
-			//this clipping should take only last painted slots in ancestor tree which
+			//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));
 		}
@@ -504,124 +501,83 @@ namespace Crow
 		protected virtual Size measureRawSize () {
 			return Bounds.Size;
 		}
-		/// <summary>
-		/// Delete all ref's to this LQI (local and inQueue)
-		/// </summary>
-		void deleteLQI(int lt){
-			int i = 0;
-			while (i < RegisteredLQINodes.Count) {
-				if (((int)RegisteredLQINodes [i].Value.LayoutType & lt) > 0) {
-					Interface.LayoutingQueue.Remove (RegisteredLQINodes [i]);
-					RegisteredLQINodes.RemoveAt (i);
-				} else
-					i++;
-			}
-		}
-		/// <summary> clear current layoutingQueue items for object and
-		/// trigger a new layouting pass for a layoutType </summary>
-		public virtual void RegisterForLayouting(int layoutType)
-		{
+			
+		public virtual void RegisterForLayouting(LayoutingType layoutType){
 			if (Parent == null)
 				return;
-			#if DEBUG_LAYOUTING
-			Debug.WriteLine ("RegisterForLayouting => {1}->{0}", layoutType, this.ToString());
-			#endif
+			//dont set position for stretched item
+			if (Width == 0)
+				layoutType &= (~LayoutingType.X);
+			if (Height == 0)
+				layoutType &= (~LayoutingType.Y);
 
-			deleteLQI (layoutType);
-			if ((layoutType & (int)LayoutingType.Width) > 0) {
-				if (Bounds.Width == 0) //stretch in parent
-						Interface.LayoutingQueue.EnqueueAfterParentSizing (LayoutingType.Width, this);
-				else if (Bounds.Width < 0) //fit 
-						Interface.LayoutingQueue.EnqueueBeforeParentSizing (LayoutingType.Width, this);
-				else					
-					RegisteredLQINodes.Add(
-						Interface.LayoutingQueue.AddFirst (
-							new LayoutingQueueItem (LayoutingType.Width, this)));				
+			//Prevent child repositionning in a stack
+			//TODO:this should be done inside GenericStack
+			GenericStack gs = Parent as GenericStack;
+			if (gs != null) {
+				if (gs.Orientation == Orientation.Horizontal)
+					layoutType &= (~LayoutingType.X);
+				else
+					layoutType &= (~LayoutingType.Y);
 			}
 
-			if ((layoutType & (int)LayoutingType.Height) > 0) {
-				if (Bounds.Height == 0) //stretch in parent
-						Interface.LayoutingQueue.EnqueueAfterParentSizing (LayoutingType.Height, this);
-				else if (Bounds.Height < 0) //fit 
-						Interface.LayoutingQueue.EnqueueBeforeParentSizing (LayoutingType.Height, this);
-				else{
-					RegisteredLQINodes.Add(
-						Interface.LayoutingQueue.AddFirst (
-							new LayoutingQueueItem (LayoutingType.Height, this)));				
-					
-				}
-			}
+			//prevent queueing same LayoutingType for this
+			layoutType &= (~RegisteredLayoutings);
 
-			if ((layoutType & (int)LayoutingType.X) > 0)
-					//for x positionning, sizing of parent and this have to be done
-					Interface.LayoutingQueue.EnqueueAfterThisAndParentSizing (LayoutingType.X, this);
+			if (layoutType == LayoutingType.None)
+				return;
 
-			if ((layoutType & (int)LayoutingType.Y) > 0)
-					//for x positionning, sizing of parent and this have to be done
-					Interface.LayoutingQueue.EnqueueAfterThisAndParentSizing (LayoutingType.Y, this);
-		}
+			#if DEBUG_LAYOUTING
+			Debug.WriteLine ("RegisterForLayouting => {1}->{0}", layoutType, this.ToString());
+			#endif
 
+			//enqueue LQI LayoutingTypes separately
+			if (layoutType.HasFlag (LayoutingType.Width))
+				Interface.LayoutingQueue.Enqueue (new LayoutingQueueItem (LayoutingType.Width, this));
+			if (layoutType.HasFlag (LayoutingType.Height))
+				Interface.LayoutingQueue.Enqueue (new LayoutingQueueItem (LayoutingType.Height, this));
+			if (layoutType.HasFlag (LayoutingType.X))
+				Interface.LayoutingQueue.Enqueue (new LayoutingQueueItem (LayoutingType.X, this));
+			if (layoutType.HasFlag (LayoutingType.Y))
+				Interface.LayoutingQueue.Enqueue (new LayoutingQueueItem (LayoutingType.Y, this));
+			if (layoutType.HasFlag (LayoutingType.PositionChildren))
+				Interface.LayoutingQueue.Enqueue (new LayoutingQueueItem (LayoutingType.PositionChildren, this));
+		}
 
 		/// <summary> trigger dependant sizing component update </summary>
 		public virtual void OnLayoutChanges(LayoutingType  layoutType)
 		{
-			if (Parent==null)
-				return;
 			#if DEBUG_LAYOUTING
 			Debug.WriteLine ("Layout change: " + this.ToString () + ":" + LastSlots.ToString() + "=>" + Slot.ToString ());
 			#endif
-			
+
 			switch (layoutType) {
-			case LayoutingType.Width:				
-				if (Parent.getBounds ().Width < 0) {
-					Group gw = Parent as Group;
-					if (gw != null) {
-						if (Slot.Width > gw.maxChildrenWidth)
-							gw.maxChildrenWidth = Slot.Width;
-					}
-					this.Parent.RegisterForLayouting ((int)LayoutingType.Width);
-				}else if (Width != 0) //update position in parent
-					this.RegisterForLayouting ((int)LayoutingType.X);
-				GenericStack gsw = Parent as GenericStack;
-				if (gsw == null)
-					break;	
-				if ((Parent as GenericStack).Orientation == Orientation.Horizontal) {
-//					ulong idx = (ulong)gsw.Children.IndexOf (this);
-//					if (idx < gsw.stackingUpdateStartIndex)
-//						gsw.stackingUpdateStartIndex = idx;
-					this.Parent.RegisterForLayouting ((int)LayoutingType.PositionChildren);
-				}
+			case LayoutingType.Width:
+				this.RegisterForLayouting (LayoutingType.X);
 				break;
 			case LayoutingType.Height:
-				if (Parent.getBounds ().Height < 0) {
-					Group gh = Parent as Group;
-					if (gh != null) {
-						if (Slot.Width > gh.maxChildrenHeight)
-							gh.maxChildrenHeight = Slot.Height;
-					}
-					this.Parent.RegisterForLayouting ((int)LayoutingType.Height);
-				}else if (Height != 0) //update position in parent
-					this.RegisterForLayouting ((int)LayoutingType.Y);
-				GenericStack gsh = Parent as GenericStack;
-				if (gsh==null)
-					break;				
-				if (gsh.Orientation == Orientation.Vertical) {
-//					ulong idx = (ulong)gsh.Children.IndexOf (this);
-//					if (idx < gsh.stackingUpdateStartIndex)
-//						gsh.stackingUpdateStartIndex = idx;
-					this.Parent.RegisterForLayouting ((int)LayoutingType.PositionChildren);
-				}
+				this.RegisterForLayouting (LayoutingType.Y);
 				break;
 			}
-			LayoutChanged.Raise (this, new LayoutChangeEventArgs (layoutType));
+			LayoutChanged.Raise (this, new LayoutingEventArgs (layoutType));
 		}
+
 		/// <summary> Update layout component, this is where the computation of alignement
 		/// and size take place </summary>
-		public virtual void UpdateLayout (LayoutingType layoutType)
-		{		
+		/// <returns><c>true</c>, if layouting was possible, <c>false</c> if conditions were not
+		/// met and LQI has to be re-queued</returns>
+		public virtual bool UpdateLayout (LayoutingType layoutType)
+		{
+			//unset bit, it would be reset if LQI is re-queued
+			registeredLayoutings &= (~layoutType);
+
 			switch (layoutType) {
 			case LayoutingType.X:
 				if (Bounds.X == 0) {
+
+					if (Parent.RegisteredLayoutings.HasFlag (LayoutingType.Width))
+						return false;
+					
 					switch (HorizontalAlignment) {
 					case HorizontalAlignment.Left:
 						Slot.X = 0;
@@ -647,8 +603,12 @@ namespace Crow
 				break;
 			case LayoutingType.Y:
 				if (Bounds.Y == 0) {
+
+					if (Parent.RegisteredLayoutings.HasFlag (LayoutingType.Height))
+						return false;
+					
 					switch (VerticalAlignment) {
-					case VerticalAlignment.Top:
+					case VerticalAlignment.Top://this could be processed even if parent Height is not known
 						Slot.Y = 0;
 						break;
 					case VerticalAlignment.Bottom:
@@ -680,6 +640,8 @@ namespace Crow
 					Slot.Width = Width;
 				else if (Width < 0)
 					Slot.Width = measureRawSize ().Width;
+				else if (Parent.RegisteredLayoutings.HasFlag (LayoutingType.Width))
+					return false;
 				else
 					Slot.Width = Parent.ClientRectangle.Width;
 
@@ -707,6 +669,8 @@ namespace Crow
 					Slot.Height = Height;
 				else if (Height < 0)
 					Slot.Height = measureRawSize ().Height;
+				else if (Parent.RegisteredLayoutings.HasFlag (LayoutingType.Width))
+					return false;
 				else
 					Slot.Height = Parent.ClientRectangle.Height;
 
@@ -716,7 +680,6 @@ namespace Crow
 				else if (Slot.Height > MaximumSize.Height && MaximumSize.Height > 0)
 					Slot.Height = MaximumSize.Height;
 
-
 				if (LastSlots.Height == Slot.Height)
 					break;
 
@@ -727,9 +690,12 @@ namespace Crow
 				LastSlots.Height = Slot.Height;
 				break;
 			}
+
 			//if no layouting remains in queue for item, registre for redraw
-			if (this.RegisteredLQINodes.Count () <= 0 && bmp == null)
+			if (this.registeredLayoutings == LayoutingType.None && bmp == null)
 				this.RegisterForRedraw ();
+
+			return true;
 		}
 		#endregion
 
@@ -763,7 +729,6 @@ namespace Crow
 					onDraw (gr);
 				}
 				draw.Flush ();
-				//draw.WriteToPng ("/mnt/data/test.png");
 			}
 		}
 		/// <summary> Chained painting routine on the parent context of the actual cached version
@@ -909,8 +874,7 @@ namespace Crow
 			#if DEBUG_BINDING
 			Debug.WriteLine ("ResolveBinding => " + this.ToString ());
 			#endif
-
-			Dictionary<object,List<Binding>> resolved = new Dictionary<object, List<Binding>>();
+			List<Binding> resolved = new List<Binding> ();
 			foreach (Binding b in Bindings) {
 				if (!string.IsNullOrEmpty (b.DynMethodId))
 					continue;
@@ -934,12 +898,7 @@ namespace Crow
 					addHandler.Invoke (this, new object[] { del });
 					continue;
 				}
-				List<Binding> bindings = null;
-				if (!resolved.TryGetValue (b.Target.Instance, out bindings)) {
-					bindings = new List<Binding> ();
-					resolved [b.Target.Instance] = bindings;
-				}
-				bindings.Add (b);
+				resolved.Add (b);				
 			}
 
 			MethodInfo stringEquals = typeof(string).GetMethod
@@ -955,8 +914,8 @@ namespace Crow
 
 			//group;only one dynMethods by target (valuechanged event source)
 			//changed value name tested in switch
-			//IEnumerable<Binding[]> groupedByTarget = resolved.GroupBy (g => g.Target.Instance, g => g, (k, g) => g.ToArray ());
-			foreach (List<Binding> grouped in resolved.Values) {
+			IEnumerable<Binding[]> groupedByTarget = resolved.GroupBy (g => g.Target.Instance, g => g, (k, g) => g.ToArray ());
+			foreach (Binding[] grouped in groupedByTarget) {
 				int i = 0;
 				Type targetType = grouped[0].Target.Instance.GetType();
 
@@ -980,8 +939,8 @@ namespace Crow
 					il = dm.GetILGenerator(256);
 
 					endMethod = il.DefineLabel();
-					jumpTable = new System.Reflection.Emit.Label[grouped.Count];
-					for (i = 0; i < grouped.Count; i++)
+					jumpTable = new System.Reflection.Emit.Label[grouped.Length];
+					for (i = 0; i < grouped.Length; i++)
 						jumpTable [i] = il.DefineLabel ();
 					il.DeclareLocal(typeof(string));
 					il.DeclareLocal(typeof(object));
diff --git a/src/GraphicObjects/Grid.cs b/src/GraphicObjects/Grid.cs
index 1981fc60..fc3d8988 100644
--- a/src/GraphicObjects/Grid.cs
+++ b/src/GraphicObjects/Grid.cs
@@ -32,13 +32,13 @@ namespace Crow
 		public override T addChild<T> (T child)
 		{
 			T tmp = base.addChild (child);
-			this.RegisterForLayouting ((int)LayoutingType.PositionChildren);
+			this.RegisterForLayouting (LayoutingType.PositionChildren);
 			return tmp;
 		}
 		public override void removeChild (GraphicObject child)
 		{
 			base.removeChild (child);
-			this.RegisterForLayouting ((int)LayoutingType.PositionChildren);
+			this.RegisterForLayouting (LayoutingType.PositionChildren);
 		}
 
 		#region Public Properties
@@ -59,7 +59,7 @@ namespace Crow
 				_columnCount = value; 
 
 				NotifyValueChanged ("ColumnCount", ColumnCount);
-				this.RegisterForLayouting ((int)LayoutingType.PositionChildren);
+				this.RegisterForLayouting (LayoutingType.PositionChildren);
 			}
         }
 		[XmlAttributeAttribute()][DefaultValue(1)]
@@ -73,7 +73,7 @@ namespace Crow
 				_rowCount = value; 
 
 				NotifyValueChanged ("RowCount", RowCount);
-				this.RegisterForLayouting ((int)LayoutingType.PositionChildren);
+				this.RegisterForLayouting (LayoutingType.PositionChildren);
 			}
 		}
 		public virtual int CaseWidth {
@@ -125,22 +125,23 @@ namespace Crow
 			}
 		}
 
-		public override void RegisterForLayouting (int layoutType)
-		{			
-			base.RegisterForLayouting (layoutType);
 
-			if ((layoutType & (int)LayoutingType.PositionChildren) > 0)
-				Interface.LayoutingQueue.Enqueue (LayoutingType.PositionChildren, this);			
-		}
-		public override void UpdateLayout (LayoutingType layoutType)
-		{            
+		public override bool UpdateLayout (LayoutingType layoutType)
+		{
+			RegisteredLayoutings &= (~layoutType);
+
 			if (layoutType == LayoutingType.PositionChildren) {				
+
 				ComputeChildrenPositions ();
+
 				//if no layouting remains in queue for item, registre for redraw
-				if (RegisteredLQINodes.Count () <= 0 && bmp==null)
+				if (RegisteredLayoutings == LayoutingType.None && bmp==null)
 					this.RegisterForRedraw ();
-			}else
-				base.UpdateLayout(layoutType);
+				
+				return true;
+			}
+
+			return base.UpdateLayout(layoutType);
 		}
 		#endregion
 
diff --git a/src/GraphicObjects/Group.cs b/src/GraphicObjects/Group.cs
index 7f952ac1..8737b866 100644
--- a/src/GraphicObjects/Group.cs
+++ b/src/GraphicObjects/Group.cs
@@ -14,9 +14,7 @@ namespace Crow
     {
 		#region CTOR
 		public Group()
-			: base()
-		{            
-		}
+			: base(){}
 		#endregion
 
 		#region EVENT HANDLERS
@@ -25,6 +23,8 @@ namespace Crow
 
 		internal int maxChildrenWidth = 0;
 		internal int maxChildrenHeight = 0;
+		internal GraphicObject largestChild = null;
+		internal GraphicObject tallestChild = null;
 
         bool _multiSelect = false;
 		List<GraphicObject> children = new List<GraphicObject>();
@@ -33,7 +33,6 @@ namespace Crow
 
         public virtual List<GraphicObject> Children {
 			get { return children; }
-			set { children = value; }
 		}
 		[XmlAttributeAttribute()][DefaultValue(false)]
         public bool MultiSelect
@@ -48,26 +47,28 @@ namespace Crow
 			GraphicObject g = child as GraphicObject;
             Children.Add(g);
             g.Parent = this as GraphicObject;            
-			g.RegisterForLayouting ((int)LayoutingType.Sizing);
+			g.RegisterForLayouting (LayoutingType.Sizing);
+			g.LayoutChanged += OnChildLayoutChanges;
             return (T)child;
         }
         public virtual void removeChild(GraphicObject child)        
-		{			
+		{
+			child.LayoutChanged -= OnChildLayoutChanges;
 			child.ClearBinding ();
 			child.Parent = null;
             Children.Remove(child);
-			this.RegisterForLayouting ((int)LayoutingType.Sizing);
+			this.RegisterForLayouting (LayoutingType.Sizing);
         }
 		public virtual void ClearChildren()
 		{
-			int lim = children.Count;
-			for (int i = 0; i < lim; i++) {
-				GraphicObject g = Children [0];
+			while(children.Count > 0){
+				GraphicObject g = children[children.Count-1];
+				g.LayoutChanged -= OnChildLayoutChanges;
 				g.ClearBinding ();
 				g.Parent = null;
-				Children.Remove(g);				
+				Children.RemoveAt(children.Count-1);
 			}
-			this.RegisterForLayouting ((int)LayoutingType.Sizing);
+			this.RegisterForLayouting (LayoutingType.Sizing);
 			ChildrenCleared.Raise (this, new EventArgs ());
 		}
 		public void putWidgetOnTop(GraphicObject w)
@@ -86,7 +87,7 @@ namespace Crow
 				Children.Insert(0, w);
 			}
 		}
-			
+
 		#region GraphicObject overrides
 		[XmlIgnore]public override bool DrawingIsValid {
 			get {
@@ -136,40 +137,73 @@ namespace Crow
 		{
 			base.OnLayoutChanges (layoutType);
 
-			GenericStack gs = this as GenericStack;
 			//position smaller objects in group when group size is fit
 			switch (layoutType) {
 			case LayoutingType.Width:
-				if (gs != null) {
-					if (gs.Orientation == Orientation.Horizontal) {
-						this.RegisterForLayouting ((int)LayoutingType.PositionChildren);
-						break;
-					}
-				}	
-				foreach (GraphicObject c in Children.Where(ch => ch.Visible)) {
-					if (c.getBounds ().Width == 0)
-						c.RegisterForLayouting ((int)LayoutingType.Width);
-					else
-						c.RegisterForLayouting ((int)LayoutingType.X);					
+				foreach (GraphicObject c in Children) {
+					if (!c.Visible)
+						continue;					
+					c.RegisterForLayouting (LayoutingType.X | LayoutingType.Width);
 				}
 				break;
 			case LayoutingType.Height:
-				if (gs != null) {
-					if (gs.Orientation == Orientation.Vertical) {
-						this.RegisterForLayouting ((int)LayoutingType.PositionChildren);
-						break;
+				foreach (GraphicObject c in Children) {
+					if (!c.Visible)
+						continue;
+					c.RegisterForLayouting (LayoutingType.Y | LayoutingType.Height);				}
+				break;
+			}
+		}
+		public virtual void OnChildLayoutChanges (object sender, LayoutingEventArgs arg)
+		{
+			GraphicObject g = sender as GraphicObject;
+			switch (arg.LayoutType) {
+			case LayoutingType.X:
+				break;
+			case LayoutingType.Y:
+				break;
+			case LayoutingType.Width:
+				if (g.Slot.Width > maxChildrenWidth) {
+					maxChildrenWidth = g.Slot.Width;
+					largestChild = g;
+					if (this.Bounds.Width < 0)
+						this.RegisterForLayouting (LayoutingType.Width);
+				} else if (g == largestChild) {
+					//search for the new largest child
+					largestChild = null;
+					maxChildrenWidth = 0;
+					for (int i = 0; i < children.Count; i++) {
+						if (children [i].Slot.Width > maxChildrenWidth) {
+							maxChildrenWidth = children [i].Slot.Width;
+							largestChild = children [i];
+						}
 					}
+					if (this.Bounds.Width < 0)
+						this.RegisterForLayouting (LayoutingType.Width);
 				}
-				foreach (GraphicObject c in Children.Where(ch => ch.Visible)) {
-					if (c.getBounds ().Height == 0)
-						c.RegisterForLayouting ((int)LayoutingType.Height);
-					else
-						c.RegisterForLayouting ((int)LayoutingType.Y);
+				break;
+			case LayoutingType.Height:
+				if (g.Slot.Height > maxChildrenHeight) {
+					maxChildrenHeight = g.Slot.Height;
+					tallestChild = g;
+					if (this.Bounds.Height < 0)
+						this.RegisterForLayouting (LayoutingType.Height);
+				} else if (g == tallestChild) {
+					//search for the new tallest child
+					tallestChild = null;
+					maxChildrenHeight = 0;
+					for (int i = 0; i < children.Count; i++) {
+						if (children [i].Slot.Height > maxChildrenHeight) {
+							maxChildrenHeight = children [i].Slot.Height;
+							tallestChild = children [i];
+						}
+					}
+					if (this.Bounds.Height < 0)
+						this.RegisterForLayouting (LayoutingType.Height);
 				}
 				break;
 			}
 		}
-
 		public override Rectangle ContextCoordinates(Rectangle r){
 			return r + ClientRectangle.Position;
 		}	
diff --git a/src/GraphicObjects/ILayoutable.cs b/src/GraphicObjects/ILayoutable.cs
index 7bb30bce..b9a97b0e 100644
--- a/src/GraphicObjects/ILayoutable.cs
+++ b/src/GraphicObjects/ILayoutable.cs
@@ -13,9 +13,9 @@ namespace Crow
 
 		IGOLibHost HostContainer { get; }
 
-		List<LinkedListNode<LayoutingQueueItem>> RegisteredLQINodes { get; }
-		void RegisterForLayouting(int layoutType);
-		void UpdateLayout(LayoutingType layoutType);
+		LayoutingType RegisteredLayoutings { get; set; }
+		void RegisterForLayouting(LayoutingType layoutType);
+		bool UpdateLayout(LayoutingType layoutType);
 
 
 		Rectangle ContextCoordinates(Rectangle r);
diff --git a/src/GraphicObjects/Label.cs b/src/GraphicObjects/Label.cs
index d8d214c7..08e7211a 100644
--- a/src/GraphicObjects/Label.cs
+++ b/src/GraphicObjects/Label.cs
@@ -105,7 +105,7 @@ namespace Crow
 				lines = getLines;
 
 				this.registerForGraphicUpdate ();
-				this.RegisterForLayouting ((int)LayoutingType.Sizing);
+				this.RegisterForLayouting (LayoutingType.Sizing);
 				NotifyValueChanged ("Text", _text);
             }
         }
diff --git a/src/GraphicObjects/ListBox.cs b/src/GraphicObjects/ListBox.cs
index 788d835f..dfa248cf 100644
--- a/src/GraphicObjects/ListBox.cs
+++ b/src/GraphicObjects/ListBox.cs
@@ -100,9 +100,9 @@ namespace Crow
 				foreach (var item in data) {
 					ms.Seek(0,SeekOrigin.Begin);
 					GraphicObject g = Interface.Load (ms, t);
-					g.DataSource = item;
 					g.MouseClick += itemClick;
 					_list.addChild (g);
+					g.DataSource = item;
 				}
 
 				ms.Dispose ();			
diff --git a/src/GraphicObjects/Popper.cs b/src/GraphicObjects/Popper.cs
index a7e1290c..528022e7 100644
--- a/src/GraphicObjects/Popper.cs
+++ b/src/GraphicObjects/Popper.cs
@@ -60,13 +60,13 @@ namespace Crow
 			IsPopped = false;
 		}
 
-		void _content_LayoutChanged (object sender, LayoutChangeEventArgs e)
+		void _content_LayoutChanged (object sender, LayoutingEventArgs e)
 		{
 			ILayoutable tc = Content.Parent as ILayoutable;
 			if (tc == null)
 				return;
 			Rectangle r = this.ScreenCoordinates (this.Slot);
-			if (((int)e.LayoutType & (int)LayoutingType.Width) > 0) {
+			if (e.LayoutType.HasFlag(LayoutingType.Width)) {
 				if (Content.Slot.Width < tc.ClientRectangle.Width) {
 					if (r.Left + Content.Slot.Width > tc.ClientRectangle.Right)
 						Content.Left = tc.ClientRectangle.Right - Content.Slot.Width;
@@ -75,7 +75,7 @@ namespace Crow
 				} else
 					Content.Left = 0;
 			}
-			if (((int)e.LayoutType & (int)LayoutingType.Height) > 0) {
+			if (e.LayoutType.HasFlag(LayoutingType.Height)) {
 				if (Content.Slot.Height < tc.ClientRectangle.Height) {
 					if (r.Bottom + Content.Slot.Height > tc.ClientRectangle.Bottom)
 						Content.Top = r.Top - Content.Slot.Height;
@@ -166,7 +166,7 @@ namespace Crow
 				if (Content.Parent == null)
 					tc.AddWidget (Content);
 				tc.PutOnTop (Content);
-				_content_LayoutChanged (this, new LayoutChangeEventArgs (LayoutingType.Sizing));
+				_content_LayoutChanged (this, new LayoutingEventArgs (LayoutingType.Sizing));
 			}
 			Pop.Raise (this, e);
 		}
diff --git a/src/GraphicObjects/PrivateContainer.cs b/src/GraphicObjects/PrivateContainer.cs
index f4190f9b..9f787eac 100644
--- a/src/GraphicObjects/PrivateContainer.cs
+++ b/src/GraphicObjects/PrivateContainer.cs
@@ -52,7 +52,8 @@ namespace Crow
 		{
 
 			if (child != null) {
-				this.RegisterForLayouting ((int)LayoutingType.Sizing);
+				child.LayoutChanged -= OnChildLayoutChanges;
+				this.RegisterForLayouting (LayoutingType.Sizing);
 				child.Parent = null;
 			}
 
@@ -60,7 +61,8 @@ namespace Crow
 
 			if (child != null) {
 				child.Parent = this;
-				child.RegisterForLayouting ((int)LayoutingType.Sizing);
+				child.LayoutChanged += OnChildLayoutChanges;
+				child.RegisterForLayouting (LayoutingType.Sizing);
 			}
 
 			return (T)_child;
@@ -101,22 +103,36 @@ namespace Crow
 			switch (layoutType) {
 			case LayoutingType.Width:								
 				if (child != null) {
-					if (child.getBounds ().Width == 0)
-						child.RegisterForLayouting ((int)LayoutingType.Width);
-					else
-						child.RegisterForLayouting ((int)LayoutingType.X);
+					if (child.Visible)
+						child.RegisterForLayouting (LayoutingType.X | LayoutingType.Width);
 				}
 				break;
 			case LayoutingType.Height:
 				if (child != null) {
-					if (child.getBounds ().Height == 0)
-						child.RegisterForLayouting ((int)LayoutingType.Height);
-					else
-						child.RegisterForLayouting ((int)LayoutingType.Y);
+					if (child.Visible)
+						child.RegisterForLayouting (LayoutingType.Y | LayoutingType.Height);
 				}
 				break;
 			}							
 		}
+		public virtual void OnChildLayoutChanges (object sender, LayoutingEventArgs arg)
+		{
+			GraphicObject g = sender as GraphicObject;
+			switch (arg.LayoutType) {
+			case LayoutingType.X:
+				break;
+			case LayoutingType.Y:
+				break;
+			case LayoutingType.Width:
+				if (this.Bounds.Width < 0)
+					this.RegisterForLayouting (LayoutingType.Width);
+				break;
+			case LayoutingType.Height:
+				if (this.Bounds.Height < 0)
+					this.RegisterForLayouting (LayoutingType.Height);
+				break;
+			}
+		}
 
 		public override Rectangle ContextCoordinates (Rectangle r)
 		{
diff --git a/src/GraphicObjects/Scroller.cs b/src/GraphicObjects/Scroller.cs
index b2a09db5..5188baf8 100644
--- a/src/GraphicObjects/Scroller.cs
+++ b/src/GraphicObjects/Scroller.cs
@@ -100,7 +100,7 @@ namespace Crow
             : base(){}
 
 		#region GraphicObject Overrides
-		void OnChildLayoutChanges (object sender, LayoutChangeEventArgs arg)
+		void OnChildLayoutChanges (object sender, LayoutingEventArgs arg)
 		{
 			int maxScroll = MaximumScroll;
 			if (_verticalScrolling) {
diff --git a/src/GraphicObjects/Slider.cs b/src/GraphicObjects/Slider.cs
index 495683d2..a9bb5b8e 100644
--- a/src/GraphicObjects/Slider.cs
+++ b/src/GraphicObjects/Slider.cs
@@ -58,7 +58,7 @@ namespace Crow
 				if (_cursorSize == value)
 					return;
 				_cursorSize = value;
-				RegisterForLayouting ((int)LayoutingType.Sizing);
+				RegisterForLayouting (LayoutingType.Sizing);
 				registerForGraphicUpdate ();
 				NotifyValueChanged ("CursorSize", _cursorSize);
 			}
@@ -72,7 +72,7 @@ namespace Crow
 					return;
 				_orientation = value; 
 
-				RegisterForLayouting ((int)LayoutingType.All);
+				RegisterForLayouting (LayoutingType.All);
 				NotifyValueChanged ("Orientation", _orientation);
 			}
 		}
diff --git a/src/GraphicObjects/Spinner.cs b/src/GraphicObjects/Spinner.cs
index a44abb13..49d323e0 100644
--- a/src/GraphicObjects/Spinner.cs
+++ b/src/GraphicObjects/Spinner.cs
@@ -35,29 +35,12 @@ namespace Crow
 		{
 		}
 
-		#region implemented abstract members of TemplatedControl
-
-		protected override void loadTemplate (GraphicObject template = null)
-		{
-			base.loadTemplate (template);			
-		}
-
-		#endregion
-
 		void onUp (object sender, MouseButtonEventArgs e)
 		{
-//			decimal tmp = 0;
-//			if (!decimal.TryParse (labCpt.Text, out tmp))
-//				return;
-
 			Value += this.SmallIncrement;
 		}
 		void onDown (object sender, MouseButtonEventArgs e)
 		{
-//			decimal tmp = 0;
-//			if (!decimal.TryParse (labCpt.Text, out tmp))
-//				return;
-
 			Value -= this.SmallIncrement;
 		}
 
diff --git a/src/GraphicObjects/TextBox.cs b/src/GraphicObjects/TextBox.cs
index 143d148f..91122523 100644
--- a/src/GraphicObjects/TextBox.cs
+++ b/src/GraphicObjects/TextBox.cs
@@ -199,9 +199,9 @@ namespace Crow
 				break;
 			}
 			if (Width < 0)
-				RegisterForLayouting ((int)LayoutingType.Width);
+				RegisterForLayouting (LayoutingType.Width);
 			if (Height < 0)
-				RegisterForLayouting ((int)LayoutingType.Height);
+				RegisterForLayouting (LayoutingType.Height);
 			registerForGraphicUpdate();
 		}
         #endregion
diff --git a/src/GraphicObjects/TextRun.cs b/src/GraphicObjects/TextRun.cs
index bee580b3..76dde9a8 100644
--- a/src/GraphicObjects/TextRun.cs
+++ b/src/GraphicObjects/TextRun.cs
@@ -60,7 +60,7 @@ namespace Crow
                     return;
 					                
                 registerForGraphicUpdate();
-				this.RegisterForLayouting ((int)LayoutingType.Sizing);
+				this.RegisterForLayouting (LayoutingType.Sizing);
 
 
                 _text = value;