Added TileImageLoader.WinUI

MapControl/WinUI/MapControl.WinUI.csproj

@@ -33,6 +33,10 @@
         <Compile Include="..\UWP\*.cs" />
     </ItemGroup>
 
+    <ItemGroup>
+        <Compile Remove="..\UWP\TileImageLoader.UWP.cs" />
+    </ItemGroup>
+
     <ItemGroup>
         <PackageReference Include="Microsoft.ProjectReunion" Version="0.8.0" />
         <PackageReference Include="Microsoft.ProjectReunion.Foundation" Version="0.8.0" />

MapControl/WinUI/TileImageLoader.WinUI.cs

@@ -0,0 +1,88 @@
+// XAML Map Control - https://github.com/ClemensFischer/XAML-Map-Control
+// © 2021 Clemens Fischer
+// Licensed under the Microsoft Public License (Ms-PL)
+
+using System;
+using System.IO;
+using System.Threading.Tasks;
+using Microsoft.UI.Dispatching;
+using Microsoft.UI.Xaml.Media;
+
+namespace MapControl
+{
+    namespace Caching
+    {
+        public interface IImageCache
+        {
+            Task<Tuple<byte[], DateTime>> GetAsync(string key);
+
+            Task SetAsync(string key, byte[] buffer, DateTime expiration);
+        }
+    }
+
+    public partial class TileImageLoader
+    {
+        /// <summary>
+        /// Default folder path where an IImageCache instance may save cached data, i.e. C:\ProgramData\MapControl\TileCache
+        /// </summary>
+        public static string DefaultCacheFolder
+        {
+            get { return Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.CommonApplicationData), "MapControl", "TileCache"); }
+        }
+
+        /// <summary>
+        /// The IImageCache implementation used to cache tile images. The default is null.
+        /// </summary>
+        public static Caching.IImageCache Cache { get; set; }
+
+
+        private static async Task LoadCachedTileAsync(Tile tile, Uri uri, string cacheKey)
+        {
+            var cacheItem = await Cache.GetAsync(cacheKey).ConfigureAwait(false);
+            var buffer = cacheItem?.Item1;
+
+            if (cacheItem == null || cacheItem.Item2 < DateTime.UtcNow)
+            {
+                var response = await ImageLoader.GetHttpResponseAsync(uri).ConfigureAwait(false);
+
+                if (response != null) // download succeeded
+                {
+                    buffer = response.Buffer; // may be null or empty when no tile available, but still be cached
+
+                    await Cache.SetAsync(cacheKey, buffer, GetExpiration(response.MaxAge)).ConfigureAwait(false);
+                }
+            }
+            //else System.Diagnostics.Debug.WriteLine("Cached: " + cacheKey);
+
+            if (buffer != null && buffer.Length > 0)
+            {
+                await SetTileImageAsync(tile, () => ImageLoader.LoadImageAsync(buffer)).ConfigureAwait(false);
+            }
+        }
+
+        private static Task LoadTileAsync(Tile tile, TileSource tileSource)
+        {
+            return SetTileImageAsync(tile, () => tileSource.LoadImageAsync(tile.XIndex, tile.Y, tile.ZoomLevel));
+        }
+
+        public static Task SetTileImageAsync(Tile tile, Func<Task<ImageSource>> loadImageFunc)
+        {
+            var tcs = new TaskCompletionSource();
+
+            tile.Image.DispatcherQueue.TryEnqueue(DispatcherQueuePriority.Low, async () =>
+            {
+                try
+                {
+                    tile.SetImage(await loadImageFunc());
+                    tcs.TrySetResult();
+                }
+                catch (Exception ex)
+                {
+                    tcs.TrySetException(ex);
+                }
+            });
+
+            return tcs.Task;
+        }
+    }
+}