From 220597ab3114c87c14baa4f9d260f4828b457b87 Mon Sep 17 00:00:00 2001
From: ClemensFischer <fischer.clemens@gmail.com>
Date: Wed, 20 Aug 2025 19:50:22 +0200
Subject: [PATCH] Image loading with cancellation

---
 MapControl/Shared/MapImageLayer.cs        | 3 +++
 MapControl/Shared/MapTileLayerBase.cs     | 2 +-
 MapControl/Shared/TileImageLoader.cs      | 5 ++++-
 MapControl/UWP/TileImageLoader.UWP.cs     | 6 +++---
 MapControl/WinUI/TileImageLoader.WinUI.cs | 6 +++---
 5 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/MapControl/Shared/MapImageLayer.cs b/MapControl/Shared/MapImageLayer.cs
index 4abd5762..518a0a60 100644
--- a/MapControl/Shared/MapImageLayer.cs
+++ b/MapControl/Shared/MapImageLayer.cs
@@ -171,8 +171,11 @@ namespace MapControl
         protected async Task UpdateImageAsync()
         {
             updateTimer.Stop();
+
             cancellationTokenSource?.Cancel();
 
+            ClearValue(LoadingProgressProperty);
+
             if (ParentMap != null && ParentMap.ActualWidth > 0d && ParentMap.ActualHeight > 0d)
             {
                 var width = ParentMap.ActualWidth * RelativeImageSize;
diff --git a/MapControl/Shared/MapTileLayerBase.cs b/MapControl/Shared/MapTileLayerBase.cs
index fb329977..40d5437c 100644
--- a/MapControl/Shared/MapTileLayerBase.cs
+++ b/MapControl/Shared/MapTileLayerBase.cs
@@ -61,8 +61,8 @@ namespace MapControl
 
         private readonly Progress<double> loadingProgress;
         private readonly DispatcherTimer updateTimer;
-        private ITileImageLoader tileImageLoader;
         private CancellationTokenSource cancellationTokenSource;
+        private ITileImageLoader tileImageLoader;
         private MapBase parentMap;
 
         protected MapTileLayerBase()
diff --git a/MapControl/Shared/TileImageLoader.cs b/MapControl/Shared/TileImageLoader.cs
index f06241d0..b7b501db 100644
--- a/MapControl/Shared/TileImageLoader.cs
+++ b/MapControl/Shared/TileImageLoader.cs
@@ -7,6 +7,7 @@ using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using System.Security.Policy;
 using System.Threading;
 using System.Threading.Tasks;
 #if WPF
@@ -102,10 +103,12 @@ namespace MapControl
 
                         progress?.Report((double)(tileCount - pendingTiles.Count) / tileCount);
 
-                        var requestCancellationToken = RequestCancellationEnabled ? cancellationToken : CancellationToken.None;
+                        Logger?.LogTrace("[{thread}] Loading tile image {zoom}/{column}/{row}", Environment.CurrentManagedThreadId, tile.ZoomLevel, tile.Column, tile.Row);
 
                         try
                         {
+                            var requestCancellationToken = RequestCancellationEnabled ? cancellationToken : CancellationToken.None;
+
                             await LoadTileImage(tile, tileSource, cacheName, requestCancellationToken).ConfigureAwait(false);
                         }
                         catch (Exception ex)
diff --git a/MapControl/UWP/TileImageLoader.UWP.cs b/MapControl/UWP/TileImageLoader.UWP.cs
index f281fc93..f3c8d0bc 100644
--- a/MapControl/UWP/TileImageLoader.UWP.cs
+++ b/MapControl/UWP/TileImageLoader.UWP.cs
@@ -17,16 +17,16 @@ namespace MapControl
                 try
                 {
                     var image = await loadImageFunc();
-        
-                    tcs.TrySetResult(null); // tcs.Task has completed when image is loaded
 
                     if (cancellationToken.IsCancellationRequested)
                     {
                         tile.IsPending = true;
+                        tcs.TrySetCanceled(cancellationToken);
                     }
                     else
                     {
                         tile.SetImageSource(image);
+                        tcs.TrySetResult(null);
                     }
                 }
                 catch (Exception ex)
@@ -37,7 +37,7 @@ namespace MapControl
 
             if (!await tile.Image.Dispatcher.TryRunAsync(CoreDispatcherPriority.Low, LoadTileImage))
             {
-                tcs.TrySetCanceled(cancellationToken);
+                tcs.TrySetCanceled(CancellationToken.None);
             }
 
             await tcs.Task;
diff --git a/MapControl/WinUI/TileImageLoader.WinUI.cs b/MapControl/WinUI/TileImageLoader.WinUI.cs
index 75542a27..ea40bff6 100644
--- a/MapControl/WinUI/TileImageLoader.WinUI.cs
+++ b/MapControl/WinUI/TileImageLoader.WinUI.cs
@@ -18,15 +18,15 @@ namespace MapControl
                 {
                     var image = await loadImageFunc();
 
-                    tcs.TrySetResult(); // tcs.Task has completed when image is loaded
-
                     if (cancellationToken.IsCancellationRequested)
                     {
                         tile.IsPending = true;
+                        tcs.TrySetCanceled(cancellationToken);
                     }
                     else
                     {
                         tile.SetImageSource(image);
+                        tcs.TrySetResult();
                     }
                 }
                 catch (Exception ex)
@@ -37,7 +37,7 @@ namespace MapControl
 
             if (!tile.Image.DispatcherQueue.TryEnqueue(DispatcherQueuePriority.Low, LoadTileImage))
             {
-                tcs.TrySetCanceled(cancellationToken);
+                tcs.TrySetCanceled(CancellationToken.None);
             }
 
             return tcs.Task;