From 65c93d1a3ee38bc791bb7f201b012538da68efd7 Mon Sep 17 00:00:00 2001
From: ClemensFischer <fischer.clemens@gmail.com>
Date: Thu, 3 Nov 2022 20:10:17 +0100
Subject: [PATCH] Improve Data handling in WPF MapPath

---
 MapControl/Shared/MapPath.cs  | 21 ++++++++++-----------
 MapControl/WPF/MapPath.WPF.cs | 28 ++++++++++++++++++++--------
 2 files changed, 30 insertions(+), 19 deletions(-)

diff --git a/MapControl/Shared/MapPath.cs b/MapControl/Shared/MapPath.cs
index 0d1e7f1d..6675a7b5 100644
--- a/MapControl/Shared/MapPath.cs
+++ b/MapControl/Shared/MapPath.cs
@@ -68,23 +68,22 @@ namespace MapControl
 
         protected virtual void UpdateData()
         {
-#if !WINUI && !UWP
-            if (Data != null && Data.IsFrozen)
-            {
-                Data = Data.Clone(); 
-                return; // UpdateData called again from DataPropertyChanged callback
-            }
-#endif
             MapPanel.SetLocation(this, Location);
 
             if (parentMap != null && Location != null && Data != null)
             {
                 var scale = parentMap.GetScale(Location);
-                var transform = new Matrix(scale.X, 0d, 0d, scale.Y, 0d, 0d);
+                var matrix = new Matrix(scale.X, 0d, 0d, scale.Y, 0d, 0d);
+                matrix.Rotate(parentMap.ViewTransform.Rotation);
 
-                transform.Rotate(parentMap.ViewTransform.Rotation);
-
-                Data.Transform = new MatrixTransform { Matrix = transform };
+                if (Data.Transform is MatrixTransform transform)
+                {
+                    transform.Matrix = matrix;
+                }
+                else
+                {
+                    Data.Transform = new MatrixTransform { Matrix = matrix };
+                }
             }
         }
 
diff --git a/MapControl/WPF/MapPath.WPF.cs b/MapControl/WPF/MapPath.WPF.cs
index 2dda7421..ac4bf432 100644
--- a/MapControl/WPF/MapPath.WPF.cs
+++ b/MapControl/WPF/MapPath.WPF.cs
@@ -15,14 +15,7 @@ namespace MapControl
     public partial class MapPath : Shape, IWeakEventListener
     {
         public static readonly DependencyProperty DataProperty = Path.DataProperty.AddOwner(
-            typeof(MapPath), new PropertyMetadata(null,
-                (o, e) =>
-                {
-                    if (e.NewValue != e.OldValue) // Data is actually a new Geometry
-                    {
-                        ((MapPath)o).UpdateData();
-                    }
-                }));
+            typeof(MapPath), new PropertyMetadata(null, DataPropertyChanged));
 
         public Geometry Data
         {
@@ -32,6 +25,25 @@ namespace MapControl
 
         protected override Geometry DefiningGeometry => Data;
 
+        private static void DataPropertyChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e)
+        {
+            if (e.NewValue != null && !ReferenceEquals(e.NewValue, e.OldValue)) // Data is actually a new Geometry
+            {
+                var path = (MapPath)obj;
+                var data = (Geometry)e.NewValue;
+
+                if (data.IsFrozen)
+                {
+                    path.Data = data.Clone(); // DataPropertyChanged called again
+                }
+                else
+                {
+                    data.Transform = new MatrixTransform();
+                    path.UpdateData();
+                }
+            }
+        }
+
         #region Methods used only by derived classes MapPolyline, MapPolygon and MapMultiPolygon
 
         protected void DataCollectionPropertyChanged(DependencyPropertyChangedEventArgs e)