From 407f786640d58feff8398629031b553cb9b81186 Mon Sep 17 00:00:00 2001
From: ClemensFischer <fischer.clemens@gmail.com>
Date: Mon, 18 Aug 2025 22:23:19 +0200
Subject: [PATCH] MapTileLayer implementation

---
 MapControl/Shared/MapTileLayer.cs     | 29 +++++++++------------------
 MapControl/Shared/MapTileLayerBase.cs |  6 +++---
 MapControl/Shared/TileImageLoader.cs  |  4 ++--
 MapControl/Shared/WmtsTileLayer.cs    |  4 ++--
 4 files changed, 17 insertions(+), 26 deletions(-)

diff --git a/MapControl/Shared/MapTileLayer.cs b/MapControl/Shared/MapTileLayer.cs
index 232a47e6..7eb3c7b3 100644
--- a/MapControl/Shared/MapTileLayer.cs
+++ b/MapControl/Shared/MapTileLayer.cs
@@ -109,33 +109,24 @@ namespace MapControl
             return finalSize;
         }
 
-        protected override async Task UpdateTileLayerAsync(bool tileSourceChanged)
+        protected override async Task UpdateTileLayerAsync(bool resetTiles)
         {
-            var updateTiles = false;
-
             if (ParentMap == null || ParentMap.MapProjection.Type != MapProjectionType.WebMercator)
             {
-                updateTiles = TileMatrix != null;
                 TileMatrix = null;
+                Children.Clear();
+
+                await LoadTilesAsync(null, null); // stop TileImageLoader
             }
-            else
+            else if (SetTileMatrix() || resetTiles)
             {
-                if (tileSourceChanged)
-                {
-                    Tiles = new TileCollection(); // clear all
-                    updateTiles = true;
-                }
-
-                if (SetTileMatrix())
-                {
-                    updateTiles = true;
-                }
-
                 SetRenderTransform();
-            }
 
-            if (updateTiles)
-            {
+                if (resetTiles)
+                {
+                    Tiles.Clear();
+                }
+
                 UpdateTiles();
 
                 await LoadTilesAsync(Tiles, SourceName);
diff --git a/MapControl/Shared/MapTileLayerBase.cs b/MapControl/Shared/MapTileLayerBase.cs
index f04621b2..26fbc784 100644
--- a/MapControl/Shared/MapTileLayerBase.cs
+++ b/MapControl/Shared/MapTileLayerBase.cs
@@ -194,13 +194,13 @@ namespace MapControl
 
         protected abstract void SetRenderTransform();
 
-        protected abstract Task UpdateTileLayerAsync(bool tileSourceChanged);
+        protected abstract Task UpdateTileLayerAsync(bool resetTiles);
 
-        private Task UpdateTileLayer(bool tileSourceChanged)
+        private Task UpdateTileLayer(bool resetTiles)
         {
             updateTimer.Stop();
 
-            return UpdateTileLayerAsync(tileSourceChanged);
+            return UpdateTileLayerAsync(resetTiles);
         }
 
         private async void OnViewportChanged(object sender, ViewportChangedEventArgs e)
diff --git a/MapControl/Shared/TileImageLoader.cs b/MapControl/Shared/TileImageLoader.cs
index 64eb7f0c..57eb2ce0 100644
--- a/MapControl/Shared/TileImageLoader.cs
+++ b/MapControl/Shared/TileImageLoader.cs
@@ -79,9 +79,9 @@ namespace MapControl
         {
             pendingTiles?.Clear();
 
-            if (tiles != null && tileSource != null)
+            if (tileSource != null && tiles != null && (tiles = tiles.Where(tile => tile.IsPending)).Any())
             {
-                pendingTiles = new ConcurrentStack<Tile>(tiles.Where(tile => tile.IsPending).Reverse());
+                pendingTiles = new ConcurrentStack<Tile>(tiles.Reverse());
 
                 var tileCount = pendingTiles.Count;
                 var taskCount = Math.Min(tileCount, MaxLoadTasks);
diff --git a/MapControl/Shared/WmtsTileLayer.cs b/MapControl/Shared/WmtsTileLayer.cs
index 3d8a7a51..131b4404 100644
--- a/MapControl/Shared/WmtsTileLayer.cs
+++ b/MapControl/Shared/WmtsTileLayer.cs
@@ -89,9 +89,9 @@ namespace MapControl
             return finalSize;
         }
 
-        protected override async Task UpdateTileLayerAsync(bool tileSourceChanged)
+        protected override async Task UpdateTileLayerAsync(bool resetTiles)
         {
-            // tileSourceChanged is ignored here because it is always false.
+            // resetTiles is ignored here because it is always false.
 
             if (ParentMap == null ||
                 !TileMatrixSets.TryGetValue(ParentMap.MapProjection.CrsId, out WmtsTileMatrixSet tileMatrixSet))