move MouseHover logic from TextView to separate class and make it reusable

src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/ChangeMarkerMargin.cs

@@ -33,10 +33,8 @@ namespace ICSharpCode.AvalonEdit.AddIn
 		public ChangeMarkerMargin(IChangeWatcher changeWatcher)
 		{
 			this.changeWatcher = changeWatcher;
-			this.delayTimer = new DispatcherTimer() {
-				Interval = SystemParameters.MouseHoverTime
-			};
-			delayTimer.Tick += delegate { DisplayTooltip(); };
+			this.hoverLogic = new MouseHoverLogic(this);
+			this.hoverLogic.MouseHover += delegate { DisplayTooltip(); };
 			changeWatcher.ChangeOccurred += ChangeOccurred;
 		}
 		
@@ -128,19 +126,10 @@ namespace ICSharpCode.AvalonEdit.AddIn
 		Popup tooltip = new Popup() { StaysOpen = false };
 		ITextMarker marker;
 		ITextMarkerService markerService;
-		DispatcherTimer delayTimer;
-		
-		protected override void OnMouseEnter(MouseEventArgs e)
-		{
-			delayTimer.Start();
-			
-			base.OnMouseEnter(e);
-		}
+		MouseHoverLogic hoverLogic;
 
 		void DisplayTooltip()
 		{
-			delayTimer.Stop();
-			
 			int line = GetLineFromMousePosition();
 			
 			if (line == 0)
@@ -239,7 +228,6 @@ namespace ICSharpCode.AvalonEdit.AddIn
 		
 		protected override void OnMouseLeave(MouseEventArgs e)
 		{
-			delayTimer.Stop();
 			if (marker != null && !tooltip.IsOpen)
 				markerService.Remove(marker);
 			base.OnMouseLeave(e);

src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/ICSharpCode.AvalonEdit.csproj

@@ -257,6 +257,7 @@
       <DependentUpon>TextView.cs</DependentUpon>
     </Compile>
     <Compile Include="Rendering\LinkElementGenerator.cs" />
+    <Compile Include="Rendering\MouseHoverLogic.cs" />
     <Compile Include="Rendering\NewLineElementGenerator.cs" />
     <Compile Include="Rendering\SimpleTextSource.cs">
       <DependentUpon>FormattedTextElement.cs</DependentUpon>

src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/MouseHoverLogic.cs

@@ -0,0 +1,102 @@
+// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
+// This code is distributed under the GNU LGPL (for details please see \doc\license.txt)
+
+using System;
+using System.Windows;
+using System.Windows.Input;
+using System.Windows.Threading;
+
+namespace ICSharpCode.AvalonEdit.Rendering
+{
+	public class MouseHoverLogic : IDisposable
+	{
+		UIElement target;
+		
+		DispatcherTimer mouseHoverTimer;
+		Point mouseHoverStartPoint;
+		MouseEventArgs mouseHoverLastEventArgs;
+		bool mouseHovering;
+		
+		public MouseHoverLogic(UIElement target)
+		{
+			if (target == null)
+				throw new ArgumentNullException("target");
+			this.target = target;
+			this.target.MouseLeave += MouseHoverLogicMouseLeave;
+			this.target.MouseMove += MouseHoverLogicMouseMove;
+		}
+	
+		void MouseHoverLogicMouseMove(object sender, MouseEventArgs e)
+		{
+			Point newPosition = e.GetPosition(this.target);
+			Vector mouseMovement = mouseHoverStartPoint - newPosition;
+			if (Math.Abs(mouseMovement.X) > SystemParameters.MouseHoverWidth
+			    || Math.Abs(mouseMovement.Y) > SystemParameters.MouseHoverHeight)
+			{
+				StopHovering();
+				mouseHoverStartPoint = newPosition;
+				mouseHoverLastEventArgs = e;
+				mouseHoverTimer = new DispatcherTimer(SystemParameters.MouseHoverTime, DispatcherPriority.Background,
+				                                      OnMouseHoverTimerElapsed, this.target.Dispatcher);
+				mouseHoverTimer.Start();
+			}
+			// do not set e.Handled - allow others to also handle MouseMove
+		}
+	
+		void MouseHoverLogicMouseLeave(object sender, MouseEventArgs e)
+		{
+			StopHovering();
+			// do not set e.Handled - allow others to also handle MouseLeave
+		}
+		
+		void StopHovering()
+		{
+			if (mouseHoverTimer != null) {
+				mouseHoverTimer.Stop();
+				mouseHoverTimer = null;
+			}
+			if (mouseHovering) {
+				mouseHovering = false;
+				OnMouseHoverStopped(mouseHoverLastEventArgs);
+			}
+		}
+		
+		void OnMouseHoverTimerElapsed(object sender, EventArgs e)
+		{
+			mouseHoverTimer.Stop();
+			mouseHoverTimer = null;
+			
+			mouseHovering = true;
+			OnMouseHover(mouseHoverLastEventArgs);
+		}
+		
+		public event EventHandler<MouseEventArgs> MouseHover;
+		
+		protected virtual void OnMouseHover(MouseEventArgs e)
+		{
+			if (MouseHover != null) {
+				MouseHover(this, e);
+			}
+		}
+		
+		public event EventHandler<MouseEventArgs> MouseHoverStopped;
+		
+		protected virtual void OnMouseHoverStopped(MouseEventArgs e)
+		{
+			if (MouseHoverStopped != null) {
+				MouseHoverStopped(this, e);
+			}
+		}
+		
+		bool disposed;
+		
+		public void Dispose()
+		{
+			if (!disposed) {
+				this.target.MouseLeave -= MouseHoverLogicMouseLeave;
+				this.target.MouseMove -= MouseHoverLogicMouseMove;
+			}
+			disposed = true;
+		}
+	}
+}

src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/TextView.cs

@@ -55,6 +55,10 @@ namespace ICSharpCode.AvalonEdit.Rendering
 			
 			layers = new UIElementCollection(this, this);
 			InsertLayer(textLayer, KnownLayer.Text, LayerInsertionPosition.Replace);
+			
+			this.hoverLogic = new MouseHoverLogic(this);
+			this.hoverLogic.MouseHover += (sender, e) => RaiseHoverEventPair(e, PreviewMouseHoverEvent, MouseHoverEvent);
+			this.hoverLogic.MouseHoverStopped += (sender, e) => RaiseHoverEventPair(e, PreviewMouseHoverStoppedEvent, MouseHoverStoppedEvent);
 		}
 
 		#endregion
@@ -1566,63 +1570,12 @@ namespace ICSharpCode.AvalonEdit.Rendering
 			remove { RemoveHandler(MouseHoverStoppedEvent, value); }
 		}
 		
-		DispatcherTimer mouseHoverTimer;
-		Point mouseHoverStartPoint;
-		MouseEventArgs mouseHoverLastEventArgs;
-		bool mouseHovering;
-		
-		/// <inheritdoc/>
-		protected override void OnMouseMove(MouseEventArgs e)
-		{
-			base.OnMouseMove(e);
-			Point newPosition = e.GetPosition(this);
-			Vector mouseMovement = mouseHoverStartPoint - newPosition;
-			if (Math.Abs(mouseMovement.X) > SystemParameters.MouseHoverWidth
-			    || Math.Abs(mouseMovement.Y) > SystemParameters.MouseHoverHeight)
-			{
-				StopHovering();
-				mouseHoverStartPoint = newPosition;
-				mouseHoverLastEventArgs = e;
-				mouseHoverTimer = new DispatcherTimer(SystemParameters.MouseHoverTime, DispatcherPriority.Background,
-				                                      OnMouseHoverTimerElapsed, this.Dispatcher);
-				mouseHoverTimer.Start();
-			}
-			// do not set e.Handled - allow others to also handle MouseMove
-		}
-		
-		/// <inheritdoc/>
-		protected override void OnMouseLeave(MouseEventArgs e)
-		{
-			base.OnMouseLeave(e);
-			StopHovering();
-			// do not set e.Handled - allow others to also handle MouseLeave
-		}
-		
-		void StopHovering()
-		{
-			if (mouseHoverTimer != null) {
-				mouseHoverTimer.Stop();
-				mouseHoverTimer = null;
-			}
-			if (mouseHovering) {
-				mouseHovering = false;
-				RaiseHoverEventPair(PreviewMouseHoverStoppedEvent, MouseHoverStoppedEvent);
-			}
-		}
+		MouseHoverLogic hoverLogic;
 		
-		void OnMouseHoverTimerElapsed(object sender, EventArgs e)
+		void RaiseHoverEventPair(MouseEventArgs e, RoutedEvent tunnelingEvent, RoutedEvent bubblingEvent)
 		{
-			mouseHoverTimer.Stop();
-			mouseHoverTimer = null;
-			
-			mouseHovering = true;
-			RaiseHoverEventPair(PreviewMouseHoverEvent, MouseHoverEvent);
-		}
-		
-		void RaiseHoverEventPair(RoutedEvent tunnelingEvent, RoutedEvent bubblingEvent)
-		{
-			var mouseDevice = mouseHoverLastEventArgs.MouseDevice;
-			var stylusDevice = mouseHoverLastEventArgs.StylusDevice;
+			var mouseDevice = e.MouseDevice;
+			var stylusDevice = e.StylusDevice;
 			int inputTime = Environment.TickCount;
 			var args1 = new MouseEventArgs(mouseDevice, inputTime, stylusDevice) {
 				RoutedEvent = tunnelingEvent,
@@ -1636,8 +1589,6 @@ namespace ICSharpCode.AvalonEdit.Rendering
 			};
 			RaiseEvent(args2);
 		}
-
-		
 		#endregion
 		
 		/// <summary>