From 709e0b82e0f5445082b7efb67bdc24d2cf6df6ba Mon Sep 17 00:00:00 2001
From: =?utf8?q?Jean-Philippe=20Bruy=C3=A8re?= <jp_bruyere@hotmail.com>
Date: Wed, 14 Mar 2018 21:42:59 +0100
Subject: [PATCH] scroller x, ide wip

---
 Templates/ComboBox.template                   |   2 +-
 Templates/FileDialog.template                 |   3 +-
 Templates/ListBox.template                    |   2 +-
 Templates/ScrollingListBox.template           |   2 +-
 Templates/TreeView.template                   |   2 +-
 Tests/Interfaces/Divers/clip4.crow            |   2 +-
 Tests/Interfaces/Divers/welcome.crow          |  21 +-
 .../TemplatedControl/testItemTemplateTag.crow |   2 +-
 Tests/Interfaces/Wrapper/2.2.crow             |   2 +-
 Tests/ui/showcase.crow                        |   2 +-
 src/GraphicObjects/GraphicObject.cs           |   3 +
 src/GraphicObjects/Scroller.cs                | 336 ++++++++++--------
 src/GraphicObjects/Slider.cs                  |  24 +-
 13 files changed, 208 insertions(+), 195 deletions(-)

diff --git a/Templates/ComboBox.template b/Templates/ComboBox.template
index aed500ab..7b7e8392 100755
--- a/Templates/ComboBox.template
+++ b/Templates/ComboBox.template
@@ -18,7 +18,7 @@
 	</Template>
 	<Border Background="DimGray" BorderWidth="1" Margin="1"
 		MinimumSize="{../../MinimumPopupSize}" Fit="true">
-		<Scroller Name="scroller1" Margin="2" VerticalScrolling="true"
+		<Scroller Name="scroller1" Margin="2" 
 			MaximumSize="0,200"
 			HorizontalAlignment="Left">
 			<VerticalStack
diff --git a/Templates/FileDialog.template b/Templates/FileDialog.template
index e508b3d7..6fae49c5 100644
--- a/Templates/FileDialog.template
+++ b/Templates/FileDialog.template
@@ -32,8 +32,7 @@
 							SelectedItemChanged="./onSelectedItemChanged">
 							<Template>
 								<HorizontalStack>
-									<Scroller ScrollX="{../scrollbar1.Value}"  Name="scroller1"
-										VerticalScrolling="true" HorizontalScrolling="false">
+									<Scroller ScrollX="{../scrollbar1.Value}"  Name="scroller1">
 										<VerticalStack Height="Fit" VerticalAlignment="Top"
 											Name="ItemsContainer" Margin="0" Spacing="1"/>
 									</Scroller>
diff --git a/Templates/ListBox.template b/Templates/ListBox.template
index f6d6214d..a1aea50f 100755
--- a/Templates/ListBox.template
+++ b/Templates/ListBox.template
@@ -1,6 +1,6 @@
 <?xml version="1.0"?>
 <Border BorderWidth="1" Margin="1" MinimumSize="10,10">
-	<Scroller  Name="scroller1" Margin="1" VerticalScrolling="true">
+	<Scroller  Name="scroller1" Margin="1" >
 		<VerticalStack
 			Height="Fit" Name="ItemsContainer" Margin="0" VerticalAlignment="Top"/>
 	</Scroller>
diff --git a/Templates/ScrollingListBox.template b/Templates/ScrollingListBox.template
index 56b08c03..3b098df2 100644
--- a/Templates/ScrollingListBox.template
+++ b/Templates/ScrollingListBox.template
@@ -2,7 +2,7 @@
 <Border BorderWidth="1" Background="{./Background}">
 	<HorizontalStack Margin="1">
 		<Scroller Name="scroller1" 
-				Margin="2" VerticalScrolling="true" ScrollY="{../scrollbar1.Value}">
+				Margin="2" ScrollY="{../scrollbar1.Value}">
 			<VerticalStack Height="Fit" MinimumSize="10,10"
 				Name="ItemsContainer" Margin="0" VerticalAlignment="Top"/>
 		</Scroller>
diff --git a/Templates/TreeView.template b/Templates/TreeView.template
index a1d9bc72..31514fce 100644
--- a/Templates/TreeView.template
+++ b/Templates/TreeView.template
@@ -1,6 +1,6 @@
 <?xml version="1.0"?>
 <HorizontalStack>
-	<Scroller  Name="scroller1" Margin="1" VerticalScrolling="true"
+	<Scroller  Name="scroller1" Margin="1"
 		Background="{./Background}"
 		ScrollY="{../scrollbar1.Value}">
 		<VerticalStack
diff --git a/Tests/Interfaces/Divers/clip4.crow b/Tests/Interfaces/Divers/clip4.crow
index 69fc7f12..852a4e87 100755
--- a/Tests/Interfaces/Divers/clip4.crow
+++ b/Tests/Interfaces/Divers/clip4.crow
@@ -1,6 +1,6 @@
 <?xml version="1.0"?>
 <Border Fit="true" BorderWidth="2"  >
-<Scroller CornerRadius="2" VerticalScrolling="true" Height="200" Width="300" Background="DimGray" Margin="2">
+<Scroller CornerRadius="2" Height="200" Width="300" Background="DimGray" Margin="2">
 	<VerticalStack Margin="10" VerticalAlignment="Top" Fit="true" Background="vgradient|0:BlueCrayola|1:Black" >
 		 <Label MouseEnter="{Background=Gray}" MouseLeave="{Background=hgradient|0:DarkRed|1:Transparent}" Margin="5" Background="hgradient|0:DarkRed|1:Transparent" Font="droid,20" Text="label 1"/>
 		 <Label MouseEnter="{Background=Gray}" MouseLeave="{Background=hgradient|0:DarkRed|1:Transparent}" Margin="5" Background="hgradient|0:DarkRed|1:Transparent" Font="droid,20" Text="label 2"/>
diff --git a/Tests/Interfaces/Divers/welcome.crow b/Tests/Interfaces/Divers/welcome.crow
index 22dfd749..3445ef1c 100644
--- a/Tests/Interfaces/Divers/welcome.crow
+++ b/Tests/Interfaces/Divers/welcome.crow
@@ -1,21 +1,2 @@
 <?xml version="1.0"?>
-<Border BorderStyle="Sunken" Fit="true" Background="0.7,0.7,0.7,0.5" CornerRadius="10">
-	<VerticalStack Margin="20">
-		<Image Path="#Crow.Images.Icons.crow.svg"/>
-<!--		<Label Font="Times bold, 60" Text="C.R.O.W"/>-->
-		<HorizontalStack Fit="true" DataSource="{CrowVersion}" Spacing="0">
-			<Label Foreground="Black" Font="mono, 12" Text="version: "/>		
-			<Label Foreground="Black" Font="mono, 12" Text="{Major}"/>		
-			<Label Foreground="Black" Font="mono, 12" Text="."/>
-			<Label Foreground="Black" Font="mono, 12" Text="{Minor}"/>
-			<Label Foreground="Black" Font="mono, 12" Text="."/>
-			<Label Foreground="DimGray" Font="mono, 12" Text="{Build}"/>
-		</HorizontalStack>
-		<GraphicObject Height="30"/>
-		<Label Font="20" Text="Press &lt;F2&gt; and &lt;F3&gt; to cycle into the examples"/>
-		<Label Font="20" Text="Those are basic tests used to validate changes,"/>
-		<GraphicObject Height="30"/>
-		<Label Foreground="DimGray" Font="20" Text="&lt;F5&gt; => File dialog example"/>
-		<Label Foreground="DimGray" Font="20" Text="&lt;F6&gt; => Window example"/>
-	</VerticalStack>
-</Border>
\ No newline at end of file
+<GraphicObject Height="30" Width="30" Background="#500000"/>
\ No newline at end of file
diff --git a/Tests/Interfaces/TemplatedControl/testItemTemplateTag.crow b/Tests/Interfaces/TemplatedControl/testItemTemplateTag.crow
index 54ccde15..90c475a5 100755
--- a/Tests/Interfaces/TemplatedControl/testItemTemplateTag.crow
+++ b/Tests/Interfaces/TemplatedControl/testItemTemplateTag.crow
@@ -7,7 +7,7 @@
 				<Border BorderWidth="1">
 					<HorizontalStack Margin="1">
 						<Scroller Name="scroller1" 
-								Margin="2" VerticalScrolling="true" ScrollY="{../scrollbar1.Value}">
+								Margin="2" ScrollY="{../scrollbar1.Value}">
 							<VerticalStack Height="Fit" MinimumSize="10,10"
 								Name="ItemsContainer" Margin="0" VerticalAlignment="Top"/>
 						</Scroller>
diff --git a/Tests/Interfaces/Wrapper/2.2.crow b/Tests/Interfaces/Wrapper/2.2.crow
index ceeae253..246a937d 100755
--- a/Tests/Interfaces/Wrapper/2.2.crow
+++ b/Tests/Interfaces/Wrapper/2.2.crow
@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <Window Caption="Horizontal Wrapper" Width="50%" Height="50%">
 	<VerticalStack Margin="1">
-		<Scroller Name="scroller1" ScrollX="{../scrollbar1.Value}" VerticalScrolling="False" HorizontalScrolling="true" Margin="1" Background="BlueCrayola">
+		<Scroller Name="scroller1" ScrollX="{../scrollbar1.Value}" Margin="1" Background="BlueCrayola">
 			<Wrapper HorizontalAlignment="Left" Orientation="Horizontal" Height="100%" Width="Fit" Margin="0" Background="MediumSeaGreen" Spacing="1" >
 				<GraphicObject Width="50" Height="50" Background="SeaGreen"/>
 				<GraphicObject Width="50" Height="50" Background="SeaGreen"/>
diff --git a/Tests/ui/showcase.crow b/Tests/ui/showcase.crow
index bfb234ad..61df4443 100755
--- a/Tests/ui/showcase.crow
+++ b/Tests/ui/showcase.crow
@@ -7,7 +7,7 @@
 		<Splitter/>
 		<HorizontalStack>
 			<Scroller Name="scroller1" Background="White"
-					Margin="2" VerticalScrolling="true" ScrollY="{../scrollbar1.Value}"
+					Margin="2" ScrollY="{../scrollbar1.Value}"
 					ValueChanged="./_scroller_ValueChanged">
 				<TextBox VerticalAlignment="Top" TextChanged="Tb_TextChanged"
 					Text="{source}" Multiline="true" TextAlignment="TopLeft"
diff --git a/src/GraphicObjects/GraphicObject.cs b/src/GraphicObjects/GraphicObject.cs
index 2ca07975..2533fb1b 100644
--- a/src/GraphicObjects/GraphicObject.cs
+++ b/src/GraphicObjects/GraphicObject.cs
@@ -1020,13 +1020,16 @@ namespace Crow
 			if (!string.IsNullOrEmpty (Style)) {
 				if (IFace.DefaultValuesLoader.ContainsKey (Style)) {
 					IFace.DefaultValuesLoader [Style] (this);
+					onInitialized (this, null);
 					return;
 				}
 			} else if (IFace.DefaultValuesLoader.ContainsKey (thisType.FullName)) {
 				IFace.DefaultValuesLoader [thisType.FullName] (this);
+				onInitialized (this, null);
 				return;
 			} else 	if (IFace.DefaultValuesLoader.ContainsKey (thisType.Name)) {
 				IFace.DefaultValuesLoader [thisType.Name] (this);
+				onInitialized (this, null);
 				return;
 			}
 
diff --git a/src/GraphicObjects/Scroller.cs b/src/GraphicObjects/Scroller.cs
index 397d7de0..30dd1480 100644
--- a/src/GraphicObjects/Scroller.cs
+++ b/src/GraphicObjects/Scroller.cs
@@ -42,160 +42,159 @@ namespace Crow
 		public Scroller (Interface iface) : base(iface){}
 		#endregion
 
-		bool _verticalScrolling;
-		bool _horizontalScrolling;
-		bool _scrollbarVisible;
-		int _scrollX = 0;
-		int _scrollY = 0;
-		int scrollSpeed;
-
 		public event EventHandler<ScrollingEventArgs> Scrolled;
 
+		int scrollX, scrollY, maxScrollX, maxScrollY, scrollSpeed;
+
+		/// <summary>
+		/// if true, key stroke are handled in derrived class
+		/// </summary>
+		protected bool KeyEventsOverrides = false;
+
 		#region public properties
-		[XmlAttributeAttribute][DefaultValue(true)]
-		public bool VerticalScrolling {
-			get { return _verticalScrolling; }
-			set { _verticalScrolling = value; }
-		}
+		/// <summary> Horizontal Scrolling Position </summary>
+		[XmlAttributeAttribute][DefaultValue(0)]
+		public virtual int ScrollX {
+			get { return scrollX; }
+			set {
+				if (scrollX == value)
+					return;
 
-		[XmlAttributeAttribute][DefaultValue(false)]
-        public bool HorizontalScrolling {
-			get { return _horizontalScrolling; }
-			set { _horizontalScrolling = value; }
-		}
-		[XmlAttributeAttribute][DefaultValue(true)]
-		public bool ScrollbarVisible {
-			get { return _scrollbarVisible; }
-			set { _scrollbarVisible = value; }
+				int newS = value;
+				if (newS < 0)
+					newS = 0;
+				else if (newS > maxScrollX)
+					newS = maxScrollX;
+
+				if (newS == scrollX)
+					return;
+
+				scrollX = value;
+
+				NotifyValueChanged ("ScrollX", scrollX);
+				RegisterForGraphicUpdate ();
+			}
 		}
+		/// <summary> Vertical Scrolling Position </summary>
 		[XmlAttributeAttribute][DefaultValue(0)]
-		public int ScrollX {
-			get {
-				return _scrollX;
-			}
+		public virtual int ScrollY {
+			get { return scrollY; }
 			set {
-				if (_scrollX == value)
+				if (scrollY == value)
 					return;
-				if (value < 0)
-					_scrollX = 0;
-				else if (value > Child.Slot.Width - ClientRectangle.Width)
-					_scrollX = Math.Max(0, Child.Slot.Width - ClientRectangle.Width);
-				else
-					_scrollX = value;
-				NotifyValueChanged("ScrollX", _scrollX);
-				RegisterForRedraw ();
-				Scrolled.Raise (this, new ScrollingEventArgs (Orientation.Horizontal));
+
+				int newS = value;
+				if (newS < 0)
+					newS = 0;
+				else if (newS > maxScrollY)
+					newS = maxScrollY;
+
+				if (newS == scrollY)
+					return;
+
+				scrollY = value;
+
+				NotifyValueChanged ("ScrollY", scrollY);
+				RegisterForGraphicUpdate ();
 			}
 		}
+		/// <summary> Horizontal Scrolling maximum value </summary>
 		[XmlAttributeAttribute][DefaultValue(0)]
-		public int ScrollY {
-			get {
-				return _scrollY;
-			}
+		public virtual int MaxScrollX {
+			get { return maxScrollX; }
 			set {
-				if (_scrollY == value)
+				if (maxScrollX == value)
 					return;
-				if (value < 0)
-					_scrollY = 0;
-				else if (value > Child.Slot.Height - ClientRectangle.Height)
-					_scrollY = Math.Max(0,Child.Slot.Height - ClientRectangle.Height);
-				else
-					_scrollY = value;
-				NotifyValueChanged("ScrollY", _scrollY);
-				RegisterForRedraw ();
-				Scrolled.Raise (this, new ScrollingEventArgs (Orientation.Vertical));
+
+				maxScrollX = value;
+
+				if (scrollX > maxScrollX)
+					ScrollX = maxScrollX;
+
+				NotifyValueChanged ("MaxScrollX", maxScrollX);
+				RegisterForGraphicUpdate ();
 			}
 		}
+		/// <summary> Vertical Scrolling maximum value </summary>
+		[XmlAttributeAttribute][DefaultValue(0)]
+		public virtual int MaxScrollY {
+			get { return maxScrollY; }
+			set {
+				if (maxScrollY == value)
+					return;
+
+				maxScrollY = value;
+
+				if (scrollY > maxScrollY)
+					ScrollY = maxScrollY;
 
-		[XmlIgnore]
-		public int MaximumScroll {
-			get {
-				try {
-					return VerticalScrolling ?
-						Math.Max(Child.Slot.Height - ClientRectangle.Height,0) :
-						Math.Max(Child.Slot.Width - ClientRectangle.Width,0);
-				} catch {
-					return 0;
-				}
+				NotifyValueChanged ("MaxScrollY", maxScrollY);
+				RegisterForGraphicUpdate ();
 			}
 		}
-
-		[XmlAttributeAttribute][DefaultValue(30)]
-		public int ScrollSpeed {
+		/// <summary> Mouse Wheel Scrolling multiplier </summary>
+		[XmlAttributeAttribute][DefaultValue(50)]
+		public virtual int ScrollSpeed {
 			get { return scrollSpeed; }
 			set {
+				if (scrollSpeed == value)
+					return;
+
 				scrollSpeed = value;
-				NotifyValueChanged("ScrollSpeed", scrollSpeed);
+
+				NotifyValueChanged ("ScrollSpeed", scrollSpeed);
 			}
 		}
 		#endregion
 
-		#region GraphicObject Overrides
-		public override void OnLayoutChanges (LayoutingType layoutType)
+		public override void SetChild (GraphicObject _child)
 		{
-			base.OnLayoutChanges (layoutType);
+			Group g = child as Group;
+			if (g != null)
+				g.ChildrenCleared -= onChildListCleared;
+			
+			base.SetChild (_child);
 
-			NotifyValueChanged("MaximumScroll", MaximumScroll);
-			if (layoutType == LayoutingType.Height) {
-				NotifyValueChanged ("PageHeight", Slot.Height);
-				if (child?.Slot.Height > 0)
-					NotifyValueChanged ("ChildHeightRatio", Slot.Height * Slot.Height / child.Slot.Height);
-			} else {
-				NotifyValueChanged ("PageWidth", Slot.Width);
-				if (child?.Slot.Width > 0)
-					NotifyValueChanged ("ChildWidthRatio", Slot.Width * Slot.Width / child.Slot.Width);
-			}
+			g = _child as Group;
+			if (g != null)
+				g.ChildrenCleared += onChildListCleared;			
 		}
-		void OnChildLayoutChanges (object sender, LayoutingEventArgs arg)
+		public override void OnChildLayoutChanges (object sender, LayoutingEventArgs arg)
 		{
-			//Debug.WriteLine ("scroller childLayoutChanges");
-			int maxScroll = MaximumScroll;
-			//Debug.WriteLine ("maxscroll={0}", maxScroll);
-			if (_verticalScrolling) {
-				if (arg.LayoutType == LayoutingType.Height) {
-					if (maxScroll < ScrollY) {
-						//Debug.WriteLine ("scrolly={0} maxscroll={1}", ScrollY, maxScroll);
-						ScrollY = maxScroll;
-					}
-					NotifyValueChanged("MaximumScroll", maxScroll);
-					if (child?.Slot.Height > 0)
-						NotifyValueChanged ("ChildHeightRatio", Slot.Height * Slot.Height / child.Slot.Height);
-				}
-			} else if (arg.LayoutType == LayoutingType.Width) {
-				if (maxScroll < ScrollX) {
-					//Debug.WriteLine ("scrolly={0} maxscroll={1}", ScrollY, maxScroll);
-					ScrollX = maxScroll;
-				}
-				NotifyValueChanged("MaximumScroll", maxScroll);
-				if (child?.Slot.Width > 0)
-					NotifyValueChanged ("ChildWidthRatio", Slot.Width * Slot.Width / child.Slot.Width);
-			}
+			base.OnChildLayoutChanges (sender, arg);
+			updateMaxScroll (arg.LayoutType);
 		}
-		void onChildListCleared(object sender, EventArgs e){
-			ScrollY = 0;
-			ScrollX = 0;
+
+
+		#region GraphicObject Overrides
+		public override Rectangle ScreenCoordinates (Rectangle r)
+		{
+			return base.ScreenCoordinates (r) - new Point((int)ScrollX,(int)ScrollY);
 		}
-		public override void SetChild (GraphicObject _child)
+		public override bool PointIsIn (ref Point m)
 		{
-			GraphicObject c = child as GraphicObject;
-			Group g = child as Group;
-			if (c != null) {
-				c.LayoutChanged -= OnChildLayoutChanges;
-				if (g != null)
-					g.ChildrenCleared -= onChildListCleared;
-			}
-			c = _child as GraphicObject;
-			g = _child as Group;
-			if (c != null) {
-				c.LayoutChanged += OnChildLayoutChanges;
-				if (g != null)
-					g.ChildrenCleared += onChildListCleared;
-			}
-			base.SetChild (_child);
+			if (!base.PointIsIn(ref m))
+				return false;
+			if (!Slot.ContainsOrIsEqual (m) || child==null)
+				return false;
+			m += new Point (ScrollX, ScrollY);
+			return true;
 		}
-		public override Rectangle ScreenCoordinates (Rectangle r)
+		public override void RegisterClip (Rectangle clip)
 		{
-			return base.ScreenCoordinates (r) - new Point((int)ScrollX,(int)ScrollY);
+			base.RegisterClip (clip - new Point(ScrollX,ScrollY));
+		}
+		public override void OnLayoutChanges (LayoutingType layoutType)
+		{
+			base.OnLayoutChanges (layoutType);
+
+			if (layoutType == LayoutingType.Height)
+				NotifyValueChanged ("PageHeight", Slot.Height);
+			else if (layoutType == LayoutingType.Width)
+				NotifyValueChanged ("PageWidth", Slot.Width);
+			else
+				return;
+			updateMaxScroll(layoutType);
 		}
 		protected override void onDraw (Context gr)
 		{
@@ -218,50 +217,75 @@ namespace Crow
 			gr.Restore ();
 		}
 
-		#region Mouse handling
-		//internal Point savedMousePos;
-
-		public override bool PointIsIn (ref Point m)
-		{
-			if (!base.PointIsIn(ref m))
-				return false;
-			if (!Slot.ContainsOrIsEqual (m) || child==null)
-				return false;
-			m += new Point (ScrollX, ScrollY);
-			return true;
-		}
-//		public override bool MouseIsIn (Point m)
-//		{
-//			return Visible ? base.ScreenCoordinates(Slot).ContainsOrIsEqual (m) : false;
-//		}
-//		public override void checkHoverWidget (MouseMoveEventArgs e)
-//		{
-//			savedMousePos = e.Position;
-//			Point m = e.Position - new Point (ScrollX, ScrollY);
-//			base.checkHoverWidget (new MouseMoveEventArgs(m.X,m.Y,e.XDelta,e.YDelta));
-//		}
+		#region Mouse & Keyboard
+		/// <summary> Process scrolling vertically, or if shift is down, vertically </summary>
 		public override void onMouseWheel (object sender, MouseWheelEventArgs e)
 		{
-			if (Child == null)
-				return;
-
-			if (VerticalScrolling )
+			base.onMouseWheel (sender, e);
+			if (IFace.Keyboard.IsKeyDown (Key.ShiftLeft))
+				ScrollX += e.Delta * ScrollSpeed;
+			else
 				ScrollY -= e.Delta * ScrollSpeed;
-			if (HorizontalScrolling )
-				ScrollX -= e.Delta * ScrollSpeed;
 		}
-//		public override void onMouseMove (object sender, MouseMoveEventArgs e)
-//		{
-//			savedMousePos.X += e.XDelta;
-//			savedMousePos.Y += e.YDelta;
-//			base.onMouseMove (sender, new MouseMoveEventArgs(savedMousePos.X,savedMousePos.Y,e.XDelta,e.YDelta));
-//		}
-		public override void RegisterClip (Rectangle clip)
+		/// <summary> Process scrolling with arrow keys, home and end keys. </summary>
+		public override void onKeyDown (object sender, KeyboardKeyEventArgs e)
 		{
-			base.RegisterClip (clip - new Point(ScrollX,ScrollY));
+			base.onKeyDown (sender, e);
+
+			if (KeyEventsOverrides)
+				return;
+
+			switch (e.Key) {
+			case Key.Up:
+				ScrollY--;
+				break;
+			case Key.Down:
+				ScrollY++;
+				break;
+			case Key.Left:
+				ScrollX--;
+				break;
+			case Key.Right:
+				ScrollX++;
+				break;
+			case Key.Home:
+				ScrollX = 0;
+				ScrollY = 0;
+				break;
+			case Key.End:
+				ScrollX = MaxScrollX;
+				ScrollY = MaxScrollY;
+				break;
+			}
 		}
 		#endregion
 
 		#endregion
+
+		void updateMaxScroll (LayoutingType lt){
+			if (Child == null) {
+				MaxScrollX = 0;
+				MaxScrollY = 0;
+				return;
+			}
+
+			Rectangle cb = ClientRectangle;
+
+			if (lt == LayoutingType.Height) {
+				MaxScrollY = child.Slot.Height - cb.Height;
+				if (child.Slot.Height > 0)
+					NotifyValueChanged ("ChildHeightRatio", Slot.Height * Slot.Height / child.Slot.Height);			
+			} else if (lt == LayoutingType.Width) {
+				MaxScrollX = child.Slot.Width - cb.Width;
+				if (child.Slot.Width > 0)
+					NotifyValueChanged ("ChildWidthRatio", Slot.Width * Slot.Width / child.Slot.Width);
+			}
+		}
+		void onChildListCleared(object sender, EventArgs e){
+			ScrollY = 0;
+			ScrollX = 0;
+		}
+
+
     }
 }
diff --git a/src/GraphicObjects/Slider.cs b/src/GraphicObjects/Slider.cs
index 4492c406..2bdd5b8a 100644
--- a/src/GraphicObjects/Slider.cs
+++ b/src/GraphicObjects/Slider.cs
@@ -186,16 +186,24 @@ namespace Crow
 			}
 			cursor.Inflate (-1);
         }
-        
+		Point mouseDownInit;
+		double mouseDownInitValue;
+
 		#region mouse handling
 		public override void onMouseDown (object sender, MouseButtonEventArgs e)
 		{
 			base.onMouseDown (sender, e);
-
+			mouseDownInit = ScreenPointToLocal (e.Position);
+			mouseDownInitValue = Value;
 			Rectangle cursInScreenCoord = ScreenCoordinates (cursor + Slot.Position);
-			if (cursInScreenCoord.ContainsOrIsEqual (e.Position))
+			if (cursInScreenCoord.ContainsOrIsEqual (e.Position)){
+//				Rectangle r = ClientRectangle;
+//				if (r.Width - _cursorSize > 0) {
+//					double unit = (Maximum - Minimum) / (double)(r.Width - _cursorSize);
+//					mouseDownInit += new Point ((int)(Value / unit), (int)(Value / unit));
+//				}
 				holdCursor = true;
-			else if (_orientation == Orientation.Horizontal) {
+			}else if (_orientation == Orientation.Horizontal) {
 				if (e.Position.X < cursInScreenCoord.Left)
 					Value -= LargeIncrement;
 				else
@@ -216,26 +224,24 @@ namespace Crow
 		public override void onMouseMove (object sender, MouseMoveEventArgs e)
 		{
 			if (holdCursor) {				
-				Point m = ScreenPointToLocal (e.Position);
+				Point m = ScreenPointToLocal (e.Position) - mouseDownInit;
 				Rectangle r = ClientRectangle;
 
 				if (_orientation == Orientation.Horizontal) {
 					if (r.Width - _cursorSize == 0)
 						return;					
 					double unit = (Maximum - Minimum) / (double)(r.Width - _cursorSize);
-					double tmp = (double)m.X * unit;
+					double tmp = mouseDownInitValue + (double)m.X * unit;
 					tmp -= tmp % SmallIncrement;
 					Value = tmp;
 				} else {
 					if (r.Height - _cursorSize == 0)
 						return;					
 					double unit = (Maximum - Minimum) / (double)(r.Height - _cursorSize);
-					double tmp = (double)m.Y * unit;
+					double tmp = mouseDownInitValue + (double)m.Y * unit;
 					tmp -= tmp % SmallIncrement;
 					Value = tmp;
 				}
-
-
 			}
 			
 			base.onMouseMove (sender, e);
-- 
2.47.3