From e7556fbf398e4304ac32b03917b79a62e24ed25e Mon Sep 17 00:00:00 2001
From: Steven Kirk <grokys@gmail.com>
Date: Tue, 8 Mar 2016 21:24:17 +0100
Subject: [PATCH] Expose IVisual.VisualRoot.

---
 src/Perspex.SceneGraph/Visual.cs                | 17 +++++------------
 src/Perspex.SceneGraph/VisualTree/IVisual.cs    |  6 ++++++
 .../VisualTree/VisualExtensions.cs              | 10 +---------
 3 files changed, 12 insertions(+), 21 deletions(-)

diff --git a/src/Perspex.SceneGraph/Visual.cs b/src/Perspex.SceneGraph/Visual.cs
index 575f555617..63b7bf14f1 100644
--- a/src/Perspex.SceneGraph/Visual.cs
+++ b/src/Perspex.SceneGraph/Visual.cs
@@ -77,19 +77,8 @@ namespace Perspex
         public static readonly StyledProperty<int> ZIndexProperty =
             PerspexProperty.Register<Visual, int>(nameof(ZIndex));
 
-        /// <summary>
-        /// The visual's bounds relative to its parent.
-        /// </summary>
         private Rect _bounds;
-
-        /// <summary>
-        /// Holds the parent of the visual.
-        /// </summary>
         private IVisual _visualParent;
-
-        /// <summary>
-        /// The logger for visual-level events.
-        /// </summary>
         private readonly ILogger _visualLogger;
 
         /// <summary>
@@ -239,6 +228,11 @@ namespace Perspex
         /// </summary>
         IVisual IVisual.VisualParent => _visualParent;
 
+        /// <summary>
+        /// Gets the root of the visual tree, if the control is attached to a visual tree.
+        /// </summary>
+        IRenderRoot IVisual.VisualRoot { get; }
+
         /// <summary>
         /// Invalidates the visual and queues a repaint.
         /// </summary>
@@ -483,7 +477,6 @@ namespace Perspex
             _visualLogger.Verbose("Attached to visual tree");
 
             VisualRoot = e.Root;
-
             OnAttachedToVisualTree(e);
 
             if (VisualChildren != null)
diff --git a/src/Perspex.SceneGraph/VisualTree/IVisual.cs b/src/Perspex.SceneGraph/VisualTree/IVisual.cs
index 904d6529fe..bac8b5bd2e 100644
--- a/src/Perspex.SceneGraph/VisualTree/IVisual.cs
+++ b/src/Perspex.SceneGraph/VisualTree/IVisual.cs
@@ -4,6 +4,7 @@
 using System;
 using Perspex.Collections;
 using Perspex.Media;
+using Perspex.Rendering;
 
 namespace Perspex.VisualTree
 {
@@ -80,6 +81,11 @@ namespace Perspex.VisualTree
         /// </summary>
         IVisual VisualParent { get; }
 
+        /// <summary>
+        /// Gets the root of the visual tree, if the control is attached to a visual tree.
+        /// </summary>
+        IRenderRoot VisualRoot { get; }
+
         /// <summary>
         /// Gets or sets the Z index of the node.
         /// </summary>
diff --git a/src/Perspex.SceneGraph/VisualTree/VisualExtensions.cs b/src/Perspex.SceneGraph/VisualTree/VisualExtensions.cs
index d08682c829..bb0da6db03 100644
--- a/src/Perspex.SceneGraph/VisualTree/VisualExtensions.cs
+++ b/src/Perspex.SceneGraph/VisualTree/VisualExtensions.cs
@@ -176,15 +176,7 @@ namespace Perspex.VisualTree
         {
             Contract.Requires<ArgumentNullException>(visual != null);
 
-            var parent = visual.VisualParent;
-
-            while (parent != null)
-            {
-                visual = parent;
-                parent = visual.VisualParent;
-            }
-
-            return visual;
+            return visual.VisualRoot as IVisual;
         }
 
         /// <summary>