From b6ed3bdbae40259f742861b63ee38304718cd826 Mon Sep 17 00:00:00 2001
From: Dariusz Komosinski <darek.komosinski@gmail.com>
Date: Sat, 30 Nov 2019 15:29:29 +0100
Subject: [PATCH] Move invalidation function to LayoutHelper.

---
 src/Avalonia.Controls/TopLevel.cs   |  2 +-
 src/Avalonia.Layout/LayoutHelper.cs | 27 +++++++++++++++++++++++++++
 src/Avalonia.Layout/Layoutable.cs   | 28 +---------------------------
 3 files changed, 29 insertions(+), 28 deletions(-)

diff --git a/src/Avalonia.Controls/TopLevel.cs b/src/Avalonia.Controls/TopLevel.cs
index 533f743f0b..5a8711a21c 100644
--- a/src/Avalonia.Controls/TopLevel.cs
+++ b/src/Avalonia.Controls/TopLevel.cs
@@ -299,7 +299,7 @@ namespace Avalonia.Controls
         /// <param name="scaling">The window scaling.</param>
         protected virtual void HandleScalingChanged(double scaling)
         {
-            InvalidateSelfAndDescendantsMeasure();
+            LayoutHelper.InvalidateSelfAndChildrenMeasure(this);
         }
 
         /// <inheritdoc/>
diff --git a/src/Avalonia.Layout/LayoutHelper.cs b/src/Avalonia.Layout/LayoutHelper.cs
index cfb4b14b1c..6ca4647c24 100644
--- a/src/Avalonia.Layout/LayoutHelper.cs
+++ b/src/Avalonia.Layout/LayoutHelper.cs
@@ -2,6 +2,7 @@
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
 using System;
+using Avalonia.VisualTree;
 
 namespace Avalonia.Layout
 {
@@ -61,5 +62,31 @@ namespace Avalonia.Layout
 
             return availableSize;
         }
+
+        /// <summary>
+        /// Invalidates measure for this instance and all visual children recursively.
+        /// </summary>
+        public static void InvalidateSelfAndChildrenMeasure(ILayoutable control)
+        {
+            void InnerInvalidateMeasure(IVisual target)
+            {
+                if (target is ILayoutable targetLayoutable)
+                {
+                    targetLayoutable.InvalidateMeasure();
+                }
+
+                var visualChildren = target.VisualChildren;
+                var visualChildrenCount = visualChildren.Count;
+
+                for (int i = 0; i < visualChildrenCount; i++)
+                {
+                    IVisual child = visualChildren[i];
+
+                    InnerInvalidateMeasure(child);
+                }
+            }
+
+            InnerInvalidateMeasure(control);
+        }
     }
 }
diff --git a/src/Avalonia.Layout/Layoutable.cs b/src/Avalonia.Layout/Layoutable.cs
index f9e438cbeb..9d0a5c57ee 100644
--- a/src/Avalonia.Layout/Layoutable.cs
+++ b/src/Avalonia.Layout/Layoutable.cs
@@ -692,36 +692,10 @@ namespace Avalonia.Layout
             return finalSize;
         }
 
-        /// <summary>
-        /// Invalidates measure for this instance and all visual children.
-        /// </summary>
-        protected void InvalidateSelfAndDescendantsMeasure()
-        {
-            void InnerInvalidateMeasure(IVisual target)
-            {
-                if (target is ILayoutable layoutable)
-                {
-                    layoutable.InvalidateMeasure();
-                }
-
-                var visualChildren = target.VisualChildren;
-                var visualChildrenCount = visualChildren.Count;
-
-                for (int i = 0; i < visualChildrenCount; i++)
-                {
-                    IVisual child = visualChildren[i];
-
-                    InnerInvalidateMeasure(child);
-                }
-            }
-
-            InnerInvalidateMeasure(this);
-        }
-
         /// <inheritdoc/>
         protected sealed override void OnVisualParentChanged(IVisual oldParent, IVisual newParent)
         {
-            InvalidateSelfAndDescendantsMeasure();
+            LayoutHelper.InvalidateSelfAndChildrenMeasure(this);
 
             base.OnVisualParentChanged(oldParent, newParent);
         }