Added IInputRoot.PointerOverElement.

To track element currently under pointer on a window.

src/Perspex.Controls/TopLevel.cs

@@ -41,6 +41,12 @@ namespace Perspex.Controls
         public static readonly PerspexProperty<bool> IsActiveProperty =
             PerspexProperty.Register<TopLevel, bool>("IsActive");
 
+        /// <summary>
+        /// Defines the <see cref="IInputRoot.PointerOverElement"/> property.
+        /// </summary>
+        public static readonly PerspexProperty<IInputElement> PointerOverElementProperty =
+            PerspexProperty.Register<TopLevel, IInputElement>(nameof(IInputRoot.PointerOverElement));
+
         /// <summary>
         /// The dispatcher for the window.
         /// </summary>
@@ -240,6 +246,15 @@ namespace Perspex.Controls
             get { return this.keyboardNavigationHandler; }
         }
 
+        /// <summary>
+        /// Gets or sets the input element that the pointer is currently over.
+        /// </summary>
+        IInputElement IInputRoot.PointerOverElement
+        {
+            get { return this.GetValue(PointerOverElementProperty); }
+            set { this.SetValue(PointerOverElementProperty, value); }
+        }
+
         /// <summary>
         /// Gets or sets a value indicating whether access keys are shown in the window.
         /// </summary>

src/Perspex.Diagnostics/DevTools.cs

@@ -98,7 +98,19 @@ namespace Perspex.Diagnostics
                             },
                             new TextBlock
                             {
-                                [!TextBlock.TextProperty] = this.viewModel.WhenAnyValue(x => x.FocusedControl).Select(x => x?.GetType().Name)
+                                [!TextBlock.TextProperty] = this.viewModel
+                                    .WhenAnyValue(x => x.FocusedControl)
+                                    .Select(x => x?.GetType().Name ?? "(null)")
+                            },
+                            new TextBlock
+                            {
+                                Text = "Pointer Over: "
+                            },
+                            new TextBlock
+                            {
+                                [!TextBlock.TextProperty] = this.viewModel
+                                    .WhenAnyValue(x => x.PointerOverElement)
+                                    .Select(x => x?.GetType().Name ?? "(null)")
                             }
                         }
                     }

src/Perspex.Diagnostics/ViewModels/DevToolsViewModel.cs

@@ -7,6 +7,7 @@
 namespace Perspex.Diagnostics.ViewModels
 {
     using System;
+    using System.Reactive.Linq;
     using Perspex.Controls;
     using Perspex.Input;
     using ReactiveUI;
@@ -21,6 +22,8 @@ namespace Perspex.Diagnostics.ViewModels
 
         private ObservableAsPropertyHelper<IInputElement> focusedControl;
 
+        private ObservableAsPropertyHelper<IInputElement> pointerOverElement;
+
         public DevToolsViewModel()
         {
             this.WhenAnyValue(x => x.Root).Subscribe(x =>
@@ -29,8 +32,14 @@ namespace Perspex.Diagnostics.ViewModels
                 this.VisualTree = new VisualTreeViewModel(this.root);
             });
 
-            this.focusedControl = KeyboardDevice.Instance.WhenAnyValue(x => x.FocusedElement)
+            this.focusedControl = KeyboardDevice.Instance
+                .WhenAnyValue(x => x.FocusedElement)
                 .ToProperty(this, x => x.FocusedControl);
+
+            this.pointerOverElement = this.WhenAnyValue(x => x.Root, x => x as TopLevel)
+                .Select(x => x != null ? x.GetObservable(TopLevel.PointerOverElementProperty) : Observable.Empty<IInputElement>())
+                .Switch()
+                .ToProperty(this, x => x.PointerOverElement);
         }
 
         public Control Root
@@ -55,5 +64,10 @@ namespace Perspex.Diagnostics.ViewModels
         {
             get { return this.focusedControl.Value; }
         }
+
+        public IInputElement PointerOverElement
+        {
+            get { return this.pointerOverElement.Value; }
+        }
     }
 }

src/Perspex.Input/IInputRoot.cs

@@ -21,6 +21,11 @@ namespace Perspex.Input
         /// </summary>
         IKeyboardNavigationHandler KeyboardNavigationHandler { get; }
 
+        /// <summary>
+        /// Gets or sets the input element that the pointer is currently over.
+        /// </summary>
+        IInputElement PointerOverElement { get; set; }
+
         /// <summary>
         /// Gets or sets a value indicating whether access keys are shown in the window.
         /// </summary>

src/Perspex.Input/MouseDevice.cs

@@ -101,9 +101,9 @@ namespace Perspex.Input
             }
         }
 
-        private void LeaveWindow(IMouseDevice device, IInputElement root)
+        private void LeaveWindow(IMouseDevice device, IInputRoot root)
         {
-            this.ClearPointerOver(this);
+            this.ClearPointerOver(this, root);
         }
 
         private void MouseDown(IMouseDevice device, uint timestamp, IInputElement root, Point p)
@@ -142,13 +142,13 @@ namespace Perspex.Input
             }
         }
 
-        private void MouseMove(IMouseDevice device, IInputElement root, Point p)
+        private void MouseMove(IMouseDevice device, IInputRoot root, Point p)
         {
             IInteractive source;
 
             if (this.Captured == null)
             {
-                this.SetPointerOver(this, root, p);
+                this.SetPointerOver(this, root, root, p);
                 source = root as IInteractive;
             }
             else
@@ -160,7 +160,7 @@ namespace Perspex.Input
                     offset += ancestor.Bounds.Position;
                 }
 
-                this.SetPointerOver(this, this.Captured, p - offset);
+                this.SetPointerOver(this, root, this.Captured, p - offset);
                 source = this.Captured as IInteractive;
             }
 
@@ -175,7 +175,7 @@ namespace Perspex.Input
             }
         }
 
-        private void MouseUp(IMouseDevice device, IInputElement root, Point p)
+        private void MouseUp(IMouseDevice device, IInputRoot root, Point p)
         {
             var hit = this.HitTest(root, p);
 
@@ -195,7 +195,7 @@ namespace Perspex.Input
             }
         }
 
-        private void MouseWheel(IMouseDevice device, IInputElement root, Point p,  Vector delta)
+        private void MouseWheel(IMouseDevice device, IInputRoot root, Point p,  Vector delta)
         {
             var hit = this.HitTest(root, p);
 
@@ -228,7 +228,7 @@ namespace Perspex.Input
             return this.Captured ?? root.InputHitTest(p);
         }
 
-        private void ClearPointerOver(IPointerDevice device)
+        private void ClearPointerOver(IPointerDevice device, IInputRoot root)
         {
             foreach (var control in this.pointerOvers.ToList())
             {
@@ -242,9 +242,11 @@ namespace Perspex.Input
                 this.pointerOvers.Remove(control);
                 control.RaiseEvent(e);
             }
+
+            root.PointerOverElement = null;
         }
 
-        private void SetPointerOver(IPointerDevice device, IInputElement element, Point p)
+        private void SetPointerOver(IPointerDevice device, IInputRoot root, IInputElement element, Point p)
         {
             IEnumerable<IInputElement> hits = element.GetInputElementsAt(p);
 
@@ -273,6 +275,10 @@ namespace Perspex.Input
                 this.pointerOvers.Add(control);
                 control.RaiseEvent(e);
             }
+
+            System.Diagnostics.Debug.WriteLine(hits.FirstOrDefault());
+
+            root.PointerOverElement = hits.FirstOrDefault();
         }
     }
 }

src/Perspex.Input/Raw/RawMouseEventArgs.cs

@@ -22,7 +22,7 @@ namespace Perspex.Input.Raw
         public RawMouseEventArgs(
             IInputDevice device,
             uint timestamp,
-            IInputElement root,
+            IInputRoot root,
             RawMouseEventType type,
             Point position)
             : base(device, timestamp)
@@ -35,7 +35,7 @@ namespace Perspex.Input.Raw
             this.Type = type;
         }
 
-        public IInputElement Root { get; private set; }
+        public IInputRoot Root { get; private set; }
 
         public Point Position { get; private set; }
 

src/Perspex.Input/Raw/RawMouseWheelEventArgs.cs

@@ -14,7 +14,7 @@ namespace Perspex.Input.Raw
         public RawMouseWheelEventArgs(
             IInputDevice device,
             uint timestamp,
-            IInputElement root,
+            IInputRoot root,
             Point position,
             Vector delta)
             : base(device, timestamp, root, RawMouseEventType.Wheel, position)