Version 1.8.0: Fixed MapImage, added ImageTileSource to Silverlight and WinRT versions, modified TileImageLoader.

Caching/FileDbCache/Properties/AssemblyInfo.cs

@@ -8,8 +8,8 @@ using System.Runtime.InteropServices;
 [assembly: AssemblyCompany("Clemens Fischer")]
 [assembly: AssemblyCopyright("Copyright © Clemens Fischer 2012-2013")]
 [assembly: AssemblyTrademark("")]
-[assembly: AssemblyVersion("1.7.0")]
+[assembly: AssemblyVersion("1.8.0")]
-[assembly: AssemblyFileVersion("1.7.0")]
+[assembly: AssemblyFileVersion("1.8.0")]
 [assembly: AssemblyConfiguration("")]
 [assembly: AssemblyCulture("")]
 [assembly: ComVisible(false)]

Caching/ImageFileCache/ImageFileCache.cs

@@ -16,12 +16,22 @@ namespace Caching
 {
     /// <summary>
     /// ObjectCache implementation based on local image files.
-    /// The only valid data type for cached values is a byte[], which contains
+    /// The only valid data type for cached values is a byte array containing an
-    /// an 8-byte binary UTC time (as created by DateTime.ToBinary), followed
+    /// 8-byte timestamp followed by a PNG, JPEG, BMP, GIF, TIFF or WMP image buffer.
-    /// by a PNG, JPEG, BMP, GIF, TIFF or WMP image buffer.
     /// </summary>
     public class ImageFileCache : ObjectCache
     {
+        private static readonly Tuple<string, byte[]>[] imageFileTypes = new Tuple<string, byte[]>[]
+        {
+            new Tuple<string, byte[]>(".png", new byte[] { 0x89, 0x50, 0x4E, 0x47, 0xD, 0xA, 0x1A, 0xA }),
+            new Tuple<string, byte[]>(".jpg", new byte[] { 0xFF, 0xD8, 0xFF, 0xE0, 0, 0x10, 0x4A, 0x46, 0x49, 0x46, 0 }),
+            new Tuple<string, byte[]>(".bmp", new byte[] { 0x42, 0x4D }),
+            new Tuple<string, byte[]>(".gif", new byte[] { 0x47, 0x49, 0x46 }),
+            new Tuple<string, byte[]>(".tif", new byte[] { 0x49, 0x49, 42, 0 }),
+            new Tuple<string, byte[]>(".tif", new byte[] { 0x4D, 0x4D, 0, 42 }),
+            new Tuple<string, byte[]>(".wdp", new byte[] { 0x49, 0x49, 0xBC }),
+        };
+
         private static readonly FileSystemAccessRule fullControlRule = new FileSystemAccessRule(
             new SecurityIdentifier(WellKnownSidType.BuiltinUsersSid, null),
             FileSystemRights.FullControl, AccessControlType.Allow);
@@ -169,18 +179,14 @@ namespace Caching
 
             var buffer = value as byte[];
 
-            if (buffer == null)
+            if (buffer == null || buffer.Length <= 8)
             {
-                throw new NotSupportedException("The parameter value must be a byte[].");
+                throw new NotSupportedException("The parameter value must be a byte[] containing at least 9 bytes.");
             }
 
             MemoryCache.Default.Set(key, buffer, policy);
 
-            var extension = GetFileExtension(buffer);
+            var path = GetPath(key) + GetFileExtension(buffer);
-
-            if (extension != null)
-            {
-                var path = GetPath(key) + extension;
 
             try
             {
@@ -200,7 +206,6 @@ namespace Caching
                 Trace.TraceWarning("ImageFileCache: Writing file {0} failed: {1}", path, ex.Message);
             }
         }
-        }
 
         public override void Set(CacheItem item, CacheItemPolicy policy)
         {
@@ -274,42 +279,24 @@ namespace Caching
             return null;
         }
 
-        private static readonly Tuple<string, byte[]>[] fileTypes = new Tuple<string, byte[]>[]
-        {
-            new Tuple<string, byte[]>(".png", new byte[] { 0x89, 0x50, 0x4E, 0x47, 0xD, 0xA, 0x1A, 0xA }),
-            new Tuple<string, byte[]>(".jpg", new byte[] { 0xFF, 0xD8, 0xFF, 0xE0, 0, 0x10, 0x4A, 0x46, 0x49, 0x46, 0 }),
-            new Tuple<string, byte[]>(".bmp", new byte[] { 0x42, 0x4D }),
-            new Tuple<string, byte[]>(".gif", new byte[] { 0x47, 0x49, 0x46 }),
-            new Tuple<string, byte[]>(".tif", new byte[] { 0x49, 0x49, 42, 0 }),
-            new Tuple<string, byte[]>(".tif", new byte[] { 0x4D, 0x4D, 0, 42 }),
-            new Tuple<string, byte[]>(".wdp", new byte[] { 0x49, 0x49, 0xBC }),
-        };
-
         private static string GetFileExtension(byte[] buffer)
         {
-            string extension = null;
+            var fileType = imageFileTypes.FirstOrDefault(t =>
-            var creationTime = DateTime.FromBinary(BitConverter.ToInt64(buffer, 0));
-
-            if (creationTime.Kind == DateTimeKind.Utc && creationTime <= DateTime.UtcNow)
-            {
-                Func<Tuple<string, byte[]>, bool> match =
-                    t =>
             {
                 int i = 0;
-                        if (t.Item2.Length + 8 <= buffer.Length)
+
+                if (t.Item2.Length <= buffer.Length - 8)
                 {
                     while (i < t.Item2.Length && t.Item2[i] == buffer[i + 8])
                     {
                         i++;
                     }
                 }
+
                 return i == t.Item2.Length;
-                    };
+            });
 
-                extension = fileTypes.Where(match).Select(t => t.Item1).FirstOrDefault();
+            return fileType != null ? fileType.Item1 : ".bin";
-            }
-
-            return extension;
         }
     }
 }

Caching/ImageFileCache/Properties/AssemblyInfo.cs

@@ -8,8 +8,8 @@ using System.Runtime.InteropServices;
 [assembly: AssemblyCompany("Clemens Fischer")]
 [assembly: AssemblyCopyright("Copyright © Clemens Fischer 2012-2013")]
 [assembly: AssemblyTrademark("")]
-[assembly: AssemblyVersion("1.7.0")]
+[assembly: AssemblyVersion("1.8.0")]
-[assembly: AssemblyFileVersion("1.7.0")]
+[assembly: AssemblyFileVersion("1.8.0")]
 [assembly: AssemblyConfiguration("")]
 [assembly: AssemblyCulture("")]
 [assembly: ComVisible(false)]

MapControl/Freezable.cs

@@ -1,22 +0,0 @@
-// XAML Map Control - http://xamlmapcontrol.codeplex.com/
-// Copyright © Clemens Fischer 2012-2013
-// Licensed under the Microsoft Public License (Ms-PL)
-
-#if NETFX_CORE
-using Windows.UI.Xaml;
-#else
-using System.Windows;
-#endif
-
-namespace MapControl
-{
-    internal static class Freezable
-    {
-        /// <summary>
-        /// Provides WPF compatibility.
-        /// </summary>
-        public static void Freeze(this DependencyObject obj)
-        {
-        }
-    }
-}

MapControl/ImageTileSource.WPF.cs

@@ -0,0 +1,14 @@
+// XAML Map Control - http://xamlmapcontrol.codeplex.com/
+// Copyright © Clemens Fischer 2012-2013
+// Licensed under the Microsoft Public License (Ms-PL)
+
+namespace MapControl
+{
+    public partial class ImageTileSource
+    {
+        public virtual bool CanLoadAsync
+        {
+            get { return false; }
+        }
+    }
+}

MapControl/ImageTileSource.cs

@@ -2,28 +2,30 @@
 // Copyright © Clemens Fischer 2012-2013
 // Licensed under the Microsoft Public License (Ms-PL)
 
+#if NETFX_CORE
+using Windows.UI.Xaml.Media;
+using Windows.UI.Xaml.Media.Imaging;
+#else
 using System.Windows.Media;
 using System.Windows.Media.Imaging;
+#endif
 
 namespace MapControl
 {
     /// <summary>
-    /// Provides the image of a map tile. ImageTileSource bypasses download and
+    /// Provides the image of a map tile. ImageTileSource bypasses downloading and
-    /// cache processing in TileImageLoader. By overriding the LoadImage method,
+    /// optional caching in TileImageLoader. By overriding the LoadImage method,
     /// an application can provide tile images from an arbitrary source.
-    /// If the CanLoadAsync property is true, the LoadImage method will be called
+    /// WPF only: If the CanLoadAsync property is true, LoadImage will be called
     /// from a separate, non-UI thread and must hence return a frozen ImageSource.
     /// </summary>
-    public class ImageTileSource : TileSource
+    public partial class ImageTileSource : TileSource
     {
-        public virtual bool CanLoadAsync
-        {
-            get { return false; }
-        }
-
         public virtual ImageSource LoadImage(int x, int y, int zoomLevel)
         {
-            return new BitmapImage(GetUri(x, y, zoomLevel));
+            var uri = GetUri(x, y, zoomLevel);
+
+            return uri != null ? new BitmapImage(uri) : null;
         }
     }
 }

MapControl/MapControl.Silverlight.csproj

@@ -70,7 +70,7 @@
   </ItemGroup>
   <ItemGroup>
     <Compile Include="AnimationEx.Silverlight.cs" />
-    <Compile Include="Freezable.cs" />
+    <Compile Include="ImageTileSource.cs" />
     <Compile Include="Int32Rect.cs" />
     <Compile Include="Location.cs" />
     <Compile Include="LocationCollection.cs" />

MapControl/MapControl.WPF.csproj

@@ -53,6 +53,7 @@
   <ItemGroup>
     <Compile Include="GlyphRunText.cs" />
     <Compile Include="ImageTileSource.cs" />
+    <Compile Include="ImageTileSource.WPF.cs" />
     <Compile Include="Location.cs" />
     <Compile Include="LocationCollection.cs" />
     <Compile Include="LocationCollectionConverter.cs" />
@@ -63,6 +64,7 @@
     <Compile Include="MapGraticule.cs" />
     <Compile Include="MapGraticule.WPF.cs" />
     <Compile Include="MapImage.cs" />
+    <Compile Include="MapImage.WPF.cs" />
     <Compile Include="MapImageLayer.cs" />
     <Compile Include="MapItem.WPF.cs" />
     <Compile Include="MapItemsControl.WPF.cs" />
@@ -74,6 +76,7 @@
     <Compile Include="MapPolyline.cs" />
     <Compile Include="MapPolyline.WPF.cs" />
     <Compile Include="MapRectangle.cs" />
+    <Compile Include="MapRectangle.WPF.cs" />
     <Compile Include="MapScale.cs" />
     <Compile Include="MapTransform.cs" />
     <Compile Include="MercatorTransform.cs" />

MapControl/MapImage.WPF.cs

@@ -0,0 +1,14 @@
+// XAML Map Control - http://xamlmapcontrol.codeplex.com/
+// Copyright © Clemens Fischer 2012-2013
+// Licensed under the Microsoft Public License (Ms-PL)
+
+namespace MapControl
+{
+    public partial class MapImage
+    {
+        static MapImage()
+        {
+            imageTransform.Freeze();
+        }
+    }
+}

MapControl/MapImage.cs

@@ -15,18 +15,13 @@ namespace MapControl
     /// <summary>
     /// Fills a rectangular area with an ImageBrush from the Source property.
     /// </summary>
-    public class MapImage : MapRectangle
+    public partial class MapImage : MapRectangle
     {
         private static readonly MatrixTransform imageTransform = new MatrixTransform
         {
             Matrix = new Matrix(1d, 0d, 0d, -1d, 0d, 1d)
         };
 
-        static MapImage()
-        {
-            imageTransform.Freeze();
-        }
-
         public static readonly DependencyProperty SourceProperty = DependencyProperty.Register(
             "Source", typeof(ImageSource), typeof(MapImage),
             new PropertyMetadata(null, (o, e) => ((MapImage)o).SourceChanged((ImageSource)e.NewValue)));
@@ -45,7 +40,6 @@ namespace MapControl
                 RelativeTransform = imageTransform
             };
 
-            imageBrush.Freeze();
             Fill = imageBrush;
         }
     }

MapControl/MapImageLayer.cs

@@ -119,7 +119,6 @@ namespace MapControl
 
                 try
                 {
-                    var bitmap = new BitmapImage();
                     var request = (HttpWebRequest)WebRequest.Create(uri);
                     request.UserAgent = "XAML Map Control";
 
@@ -128,15 +127,8 @@ namespace MapControl
                     using (var memoryStream = new MemoryStream())
                     {
                         responseStream.CopyTo(memoryStream);
-
+                        image = BitmapFrame.Create(memoryStream, BitmapCreateOptions.None, BitmapCacheOption.OnLoad);
-                        bitmap.BeginInit();
-                        bitmap.CacheOption = BitmapCacheOption.OnLoad;
-                        bitmap.StreamSource = memoryStream;
-                        bitmap.EndInit();
-                        bitmap.Freeze();
                     }
-
-                    image = bitmap;
                 }
                 catch (Exception ex)
                 {

MapControl/MapRectangle.WPF.cs

@@ -0,0 +1,14 @@
+// XAML Map Control - http://xamlmapcontrol.codeplex.com/
+// Copyright © Clemens Fischer 2012-2013
+// Licensed under the Microsoft Public License (Ms-PL)
+
+namespace MapControl
+{
+    public partial class MapRectangle
+    {
+        static MapRectangle()
+        {
+            geometryScaleTransform.Freeze();
+        }
+    }
+}

MapControl/MapRectangle.cs

@@ -16,7 +16,7 @@ namespace MapControl
     /// <summary>
     /// Fills a rectangular area defined by South, North, West and East with a Brush.
     /// </summary>
-    public class MapRectangle : MapPath
+    public partial class MapRectangle : MapPath
     {
         private const double geometryScale = 1e6;
 
@@ -26,11 +26,6 @@ namespace MapControl
             ScaleY = 1d / geometryScale
         };
 
-        static MapRectangle()
-        {
-            geometryScaleTransform.Freeze();
-        }
-
         public static readonly DependencyProperty SouthProperty = DependencyProperty.Register(
             "South", typeof(double), typeof(MapRectangle),
             new PropertyMetadata(double.NaN, (o, e) => ((MapRectangle)o).UpdateData()));

MapControl/Properties/AssemblyInfo.cs

@@ -15,8 +15,8 @@ using System.Windows;
 [assembly: AssemblyCompany("Clemens Fischer")]
 [assembly: AssemblyCopyright("Copyright © Clemens Fischer 2012-2013")]
 [assembly: AssemblyTrademark("")]
-[assembly: AssemblyVersion("1.7.0")]
+[assembly: AssemblyVersion("1.8.0")]
-[assembly: AssemblyFileVersion("1.7.0")]
+[assembly: AssemblyFileVersion("1.8.0")]
 [assembly: AssemblyConfiguration("")]
 [assembly: AssemblyCulture("")]
 [assembly: ComVisible(false)]

MapControl/Tile.Silverlight.WinRT.cs

@@ -33,12 +33,12 @@ namespace MapControl
             {
                 if (animateOpacity)
                 {
-                    var bitmapImage = image as BitmapImage;
+                    var bitmap = image as BitmapImage;
 
-                    if (bitmapImage != null)
+                    if (bitmap != null)
                     {
-                        bitmapImage.ImageOpened += BitmapImageOpened;
+                        bitmap.ImageOpened += BitmapImageOpened;
-                        bitmapImage.ImageFailed += BitmapImageFailed;
+                        bitmap.ImageFailed += BitmapImageFailed;
                     }
                     else
                     {
@@ -52,20 +52,26 @@ namespace MapControl
             }
 
             Image.Source = image;
-            HasImage = true;
+            HasImageSource = true;
         }
 
         private void BitmapImageOpened(object sender, RoutedEventArgs e)
         {
-            ((BitmapImage)sender).ImageOpened -= BitmapImageOpened;
+            var bitmap = (BitmapImage)sender;
-            ((BitmapImage)sender).ImageFailed -= BitmapImageFailed;
+
+            bitmap.ImageOpened -= BitmapImageOpened;
+            bitmap.ImageFailed -= BitmapImageFailed;
+
             Image.BeginAnimation(Image.OpacityProperty, new DoubleAnimation { To = 1d, Duration = AnimationDuration });
         }
 
         private void BitmapImageFailed(object sender, ExceptionRoutedEventArgs e)
         {
-            ((BitmapImage)sender).ImageOpened -= BitmapImageOpened;
+            var bitmap = (BitmapImage)sender;
-            ((BitmapImage)sender).ImageFailed -= BitmapImageFailed;
+
+            bitmap.ImageOpened -= BitmapImageOpened;
+            bitmap.ImageFailed -= BitmapImageFailed;
+
             Image.Source = null;
         }
     }

MapControl/Tile.WPF.cs

@@ -24,12 +24,12 @@ namespace MapControl
             {
                 if (animateOpacity)
                 {
-                    var bitmapImage = image as BitmapImage;
+                    var bitmap = image as BitmapSource;
 
-                    if (bitmapImage != null && bitmapImage.IsDownloading)
+                    if (bitmap != null && !bitmap.IsFrozen && bitmap.IsDownloading)
                     {
-                        bitmapImage.DownloadCompleted += BitmapDownloadCompleted;
+                        bitmap.DownloadCompleted += BitmapDownloadCompleted;
-                        bitmapImage.DownloadFailed += BitmapDownloadFailed;
+                        bitmap.DownloadFailed += BitmapDownloadFailed;
                     }
                     else
                     {
@@ -43,20 +43,26 @@ namespace MapControl
             }
 
             Brush.ImageSource = image;
-            HasImage = true;
+            HasImageSource = true;
         }
 
         private void BitmapDownloadCompleted(object sender, EventArgs e)
         {
-            ((BitmapImage)sender).DownloadCompleted -= BitmapDownloadCompleted;
+            var bitmap = (BitmapSource)sender;
-            ((BitmapImage)sender).DownloadFailed -= BitmapDownloadFailed;
+
+            bitmap.DownloadCompleted -= BitmapDownloadCompleted;
+            bitmap.DownloadFailed -= BitmapDownloadFailed;
+
             Brush.BeginAnimation(ImageBrush.OpacityProperty, new DoubleAnimation(1d, AnimationDuration));
         }
 
         private void BitmapDownloadFailed(object sender, ExceptionEventArgs e)
         {
-            ((BitmapImage)sender).DownloadCompleted -= BitmapDownloadCompleted;
+            var bitmap = (BitmapSource)sender;
-            ((BitmapImage)sender).DownloadFailed -= BitmapDownloadFailed;
+
+            bitmap.DownloadCompleted -= BitmapDownloadCompleted;
+            bitmap.DownloadFailed -= BitmapDownloadFailed;
+
             Brush.ImageSource = null;
         }
     }

MapControl/Tile.cs

@@ -21,7 +21,7 @@ namespace MapControl
             Y = y;
         }
 
-        public bool HasImage { get; private set; }
+        public bool HasImageSource { get; private set; }
 
         public int XIndex
         {

MapControl/TileImageLoader.Silverlight.WinRT.cs

@@ -2,37 +2,50 @@
 // Copyright © Clemens Fischer 2012-2013
 // Licensed under the Microsoft Public License (Ms-PL)
 
+using System;
 using System.Collections.Generic;
-using System.Linq;
+using System.Diagnostics;
 #if NETFX_CORE
+using Windows.UI.Xaml.Media;
 using Windows.UI.Xaml.Media.Imaging;
 #else
+using System.Windows.Media;
 using System.Windows.Media.Imaging;
 #endif
 
 namespace MapControl
 {
     /// <summary>
-    /// Loads map tile images by their URIs.
+    /// Loads map tile images.
     /// </summary>
     internal class TileImageLoader
     {
-        private readonly TileLayer tileLayer;
+        internal void BeginGetTiles(TileLayer tileLayer, IEnumerable<Tile> tiles)
-
-        internal TileImageLoader(TileLayer tileLayer)
         {
-            this.tileLayer = tileLayer;
+            var imageTileSource = tileLayer.TileSource as ImageTileSource;
-        }
 
-        internal void StartGetTiles(IEnumerable<Tile> tiles)
-        {
             foreach (var tile in tiles)
+            {
+                try
+                {
+                    ImageSource image;
+
+                    if (imageTileSource != null)
+                    {
+                        image = imageTileSource.LoadImage(tile.XIndex, tile.Y, tile.ZoomLevel);
+                    }
+                    else
                     {
                         var uri = tileLayer.TileSource.GetUri(tile.XIndex, tile.Y, tile.ZoomLevel);
 
-                if (uri != null)
+                        image = uri != null ? new BitmapImage(uri) : null;
+                    }
+
+                    tile.SetImageSource(image, tileLayer.AnimateTileOpacity);
+                }
+                catch (Exception ex)
                 {
-                    tile.SetImageSource(new BitmapImage(uri), tileLayer.AnimateTileOpacity);
+                    Debug.WriteLine("Creating tile image failed: {0}", ex.Message);
                 }
             }
         }

MapControl/TileImageLoader.WPF.cs

@@ -9,7 +9,6 @@ using System.Diagnostics;
 using System.IO;
 using System.Linq;
 using System.Net;
-using System.Net.Cache;
 using System.Runtime.Caching;
 using System.Threading;
 using System.Windows.Media;
@@ -19,18 +18,14 @@ using System.Windows.Threading;
 namespace MapControl
 {
     /// <summary>
-    /// Loads map tile images by their URIs and optionally caches the images in an ObjectCache.
+    /// Loads map tile images and optionally caches them in a System.Runtime.Caching.ObjectCache.
     /// </summary>
     public class TileImageLoader
     {
-        private readonly TileLayer tileLayer;
-        private readonly ConcurrentQueue<Tile> pendingTiles = new ConcurrentQueue<Tile>();
-        private int downloadThreadCount;
-
         /// <summary>
         /// Default Name of an ObjectCache instance that is assigned to the Cache property.
         /// </summary>
-        public static readonly string DefaultCacheName = "TileCache";
+        public const string DefaultCacheName = "TileCache";
 
         /// <summary>
         /// Default value for the directory where an ObjectCache instance may save cached data.
@@ -39,44 +34,48 @@ namespace MapControl
             Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.CommonApplicationData), "MapControl");
 
         /// <summary>
-        /// The ObjectCache used to cache tile images.
+        /// The ObjectCache used to cache tile images. The default is null.
-        /// The default is System.Runtime.Caching.MemoryCache.Default.
         /// </summary>
         public static ObjectCache Cache { get; set; }
 
         /// <summary>
-        /// The time interval after which cached images expire. The default value is 30 days.
+        /// The time interval after which cached images expire. The default value is seven days.
-        /// When an image is not retrieved from the cache during this interval it is considered
+        /// When an image is not retrieved from the cache during this interval it is considered as expired
-        /// as expired and will be removed from the cache. If an image is retrieved from the
+        /// and will be removed from the cache, provided that the cache implementation supports expiration.
-        /// cache and the CacheUpdateAge time interval has expired, the image is downloaded
+        /// If an image is retrieved from the cache and the CacheUpdateAge time interval has expired,
-        /// again and rewritten to the cache with a new expiration time.
+        /// the image is downloaded again and rewritten to the cache with a new expiration time.
         /// </summary>
         public static TimeSpan CacheExpiration { get; set; }
 
         /// <summary>
         /// The time interval after which a cached image is updated and rewritten to the cache.
-        /// The default value is one day. This time interval should be shorter than the value
+        /// The default value is one day. This time interval should not be greater than the value
         /// of the CacheExpiration property.
         /// </summary>
         public static TimeSpan CacheUpdateAge { get; set; }
 
         static TileImageLoader()
         {
-            Cache = MemoryCache.Default;
+            CacheExpiration = TimeSpan.FromDays(7);
-            CacheExpiration = TimeSpan.FromDays(30d);
+            CacheUpdateAge = TimeSpan.FromDays(1);
-            CacheUpdateAge = TimeSpan.FromDays(1d);
         }
 
-        internal TileImageLoader(TileLayer tileLayer)
+        private readonly ConcurrentQueue<Tile> pendingTiles = new ConcurrentQueue<Tile>();
-        {
+        private int threadCount;
-            this.tileLayer = tileLayer;
-        }
 
-        internal void StartGetTiles(IEnumerable<Tile> tiles)
+        internal void BeginGetTiles(TileLayer tileLayer, IEnumerable<Tile> tiles)
         {
-            if (tileLayer.TileSource != null && tiles.Any())
+            if (tiles.Any())
             {
-                ThreadPool.QueueUserWorkItem(GetTilesAsync, tiles.ToList());
+                // get current TileLayer property values in UI thread
+                var dispatcher = tileLayer.Dispatcher;
+                var tileSource = tileLayer.TileSource;
+                var sourceName = tileLayer.SourceName;
+                var maxDownloads = tileLayer.MaxParallelDownloads;
+                var animateOpacity = tileLayer.AnimateTileOpacity;
+
+                ThreadPool.QueueUserWorkItem(o =>
+                    GetTiles(tiles.ToList(), dispatcher, tileSource, sourceName, maxDownloads, animateOpacity));
             }
         }
 
@@ -86,56 +85,65 @@ namespace MapControl
             while (pendingTiles.TryDequeue(out tile)) ; // no Clear method
         }
 
-        private string GetCacheKey(Tile tile)
+        private void GetTiles(List<Tile> tiles, Dispatcher dispatcher, TileSource tileSource,
+                              string sourceName, int maxDownloads, bool animateOpacity)
         {
-            return string.Format("{0}/{1}/{2}/{3}", tileLayer.SourceName, tile.ZoomLevel, tile.XIndex, tile.Y);
+            var imageTileSource = tileSource as ImageTileSource;
-        }
 
-        private void GetTilesAsync(object tileList)
+            if (imageTileSource != null)
             {
-            var tiles = (List<Tile>)tileList;
+                if (!imageTileSource.CanLoadAsync) // call LoadImage in UI thread
-            var imageTileSource = tileLayer.TileSource as ImageTileSource;
-
-            if (imageTileSource != null && !imageTileSource.CanLoadAsync)
                 {
                     foreach (var tile in tiles)
                     {
-                    tileLayer.Dispatcher.BeginInvoke(
+                        dispatcher.BeginInvoke(
-                        (Action<Tile, ImageTileSource>)((t, ts) => t.SetImageSource(ts.LoadImage(t.XIndex, t.Y, t.ZoomLevel), tileLayer.AnimateTileOpacity)),
+                            (Action<Tile, ImageTileSource>)((t, ts) => t.SetImageSource(LoadImage(ts, t), animateOpacity)),
                             DispatcherPriority.Background, tile, imageTileSource);
                     }
+
+                    return;
                 }
-            else
+            }
+            else if (!tileSource.UriFormat.StartsWith("file:")) // always load local image files asynchronously
             {
-                if (imageTileSource == null && Cache != null &&
+                if (Cache == null || string.IsNullOrWhiteSpace(sourceName))
-                    !string.IsNullOrWhiteSpace(tileLayer.SourceName) &&
-                    !tileLayer.TileSource.UriFormat.StartsWith("file://"))
                 {
+                    // no caching here: use default asynchronous downloading and caching done by WPF
+
+                    foreach (var tile in tiles)
+                    {
+                        dispatcher.BeginInvoke(
+                            (Action<Tile, TileSource>)((t, ts) => t.SetImageSource(CreateImage(ts, t), animateOpacity)),
+                            DispatcherPriority.Background, tile, tileSource);
+                    }
+
+                    return;
+                }
+
                 var outdatedTiles = new List<Tile>(tiles.Count);
 
                 foreach (var tile in tiles)
                 {
-                        var key = GetCacheKey(tile);
+                    var key = GetCacheKey(sourceName, tile);
                     var buffer = Cache.Get(key) as byte[];
                     var image = CreateImage(buffer);
 
                     if (image != null)
                     {
-                            tileLayer.Dispatcher.BeginInvoke(
+                        dispatcher.BeginInvoke(
-                                (Action<Tile, ImageSource>)((t, i) => t.SetImageSource(i, tileLayer.AnimateTileOpacity)),
+                            (Action<Tile, ImageSource>)((t, i) => t.SetImageSource(i, animateOpacity)),
                             DispatcherPriority.Background, tile, image);
 
                         long creationTime = BitConverter.ToInt64(buffer, 0);
 
                         if (DateTime.FromBinary(creationTime) + CacheUpdateAge < DateTime.UtcNow)
                         {
-                                // update outdated cache
+                            outdatedTiles.Add(tile); // update outdated cache
-                                outdatedTiles.Add(tile);
                         }
                     }
                     else
                     {
-                            pendingTiles.Enqueue(tile);
+                        pendingTiles.Enqueue(tile); // not yet cached
                     }
                 }
 
@@ -147,18 +155,17 @@ namespace MapControl
                 pendingTiles.Enqueue(tile);
             }
 
-                while (downloadThreadCount < Math.Min(pendingTiles.Count, tileLayer.MaxParallelDownloads))
+            while (threadCount < Math.Min(pendingTiles.Count, maxDownloads))
             {
-                    Interlocked.Increment(ref downloadThreadCount);
+                Interlocked.Increment(ref threadCount);
 
-                    ThreadPool.QueueUserWorkItem(LoadTiles);
+                ThreadPool.QueueUserWorkItem(o => LoadPendingTiles(dispatcher, tileSource, sourceName, animateOpacity));
-                }
             }
         }
 
-        private void LoadTiles(object o)
+        private void LoadPendingTiles(Dispatcher dispatcher, TileSource tileSource, string sourceName, bool animateOpacity)
         {
-            var imageTileSource = tileLayer.TileSource as ImageTileSource;
+            var imageTileSource = tileSource as ImageTileSource;
             Tile tile;
 
             while (pendingTiles.TryDequeue(out tile))
@@ -168,65 +175,96 @@ namespace MapControl
 
                 if (imageTileSource != null)
                 {
+                    image = LoadImage(imageTileSource, tile);
+                }
+                else
+                {
+                    var uri = tileSource.GetUri(tile.XIndex, tile.Y, tile.ZoomLevel);
+
+                    if (uri != null)
+                    {
+                        if (uri.Scheme == "file")
+                        {
+                            image = CreateImage(uri.AbsolutePath);
+                        }
+                        else
+                        {
+                            buffer = DownloadImage(uri);
+                            image = CreateImage(buffer);
+                        }
+                    }
+                }
+
+                if (image != null || !tile.HasImageSource) // do not set null if tile already has an image (from cache)
+                {
+                    dispatcher.BeginInvoke(
+                        (Action<Tile, ImageSource>)((t, i) => t.SetImageSource(i, animateOpacity)),
+                        DispatcherPriority.Background, tile, image);
+                }
+
+                if (buffer != null && image != null)
+                {
+                    Cache.Set(GetCacheKey(sourceName, tile), buffer, new CacheItemPolicy { SlidingExpiration = CacheExpiration });
+                }
+            }
+
+            Interlocked.Decrement(ref threadCount);
+        }
+
+        private static string GetCacheKey(string sourceName, Tile tile)
+        {
+            return string.Format("{0}/{1}/{2}/{3}", sourceName, tile.ZoomLevel, tile.XIndex, tile.Y);
+        }
+
+        private static ImageSource LoadImage(ImageTileSource tileSource, Tile tile)
+        {
+            ImageSource image = null;
+
             try
             {
-                        image = imageTileSource.LoadImage(tile.XIndex, tile.Y, tile.ZoomLevel);
+                image = tileSource.LoadImage(tile.XIndex, tile.Y, tile.ZoomLevel);
             }
             catch (Exception ex)
             {
                 Trace.TraceWarning("Loading tile image failed: {0}", ex.Message);
             }
-                }
-                else
-                {
-                    var uri = tileLayer.TileSource.GetUri(tile.XIndex, tile.Y, tile.ZoomLevel);
 
-                    if (uri != null)
+            return image;
-                    {
-                        if (uri.Scheme == "http")
-                        {
-                            buffer = DownloadImage(uri);
-                            image = CreateImage(buffer);
-                        }
-                        else
-                        {
-                            image = CreateImage(uri);
-                        }
-                    }
         }
 
-                if (image != null)
+        private static ImageSource CreateImage(TileSource tileSource, Tile tile)
         {
-                    tileLayer.Dispatcher.BeginInvoke(
+            ImageSource image = null;
-                        (Action<Tile, ImageSource>)((t, i) => t.SetImageSource(i, tileLayer.AnimateTileOpacity)),
-                        DispatcherPriority.Background, tile, image);
-
-                    if (buffer != null && Cache != null)
-                    {
-                        Cache.Set(GetCacheKey(tile), buffer, new CacheItemPolicy { SlidingExpiration = CacheExpiration });
-                    }
-                }
-            }
-
-            Interlocked.Decrement(ref downloadThreadCount);
-        }
-
-        private static ImageSource CreateImage(Uri uri)
-        {
-            var image = new BitmapImage();
 
             try
             {
-                image.BeginInit();
+                image = BitmapFrame.Create(tileSource.GetUri(tile.XIndex, tile.Y, tile.ZoomLevel));
-                image.CacheOption = BitmapCacheOption.OnLoad;
-                image.UriSource = uri;
-                image.EndInit();
-                image.Freeze();
             }
             catch (Exception ex)
             {
                 Trace.TraceWarning("Creating tile image failed: {0}", ex.Message);
-                image = null;
+            }
+
+            return image;
+        }
+
+        private static ImageSource CreateImage(string path)
+        {
+            ImageSource image = null;
+
+            if (File.Exists(path))
+            {
+                try
+                {
+                    using (var stream = new FileStream(path, FileMode.Open))
+                    {
+                        image = BitmapFrame.Create(stream, BitmapCreateOptions.None, BitmapCacheOption.OnLoad);
+                    }
+                }
+                catch (Exception ex)
+                {
+                    Trace.TraceWarning("Creating tile image failed: {0}", ex.Message);
+                }
             }
 
             return image;
@@ -234,7 +272,7 @@ namespace MapControl
 
         private static ImageSource CreateImage(byte[] buffer)
         {
-            BitmapImage image = null;
+            ImageSource image = null;
 
             if (buffer != null && buffer.Length > sizeof(long))
             {
@@ -242,18 +280,12 @@ namespace MapControl
                 {
                     using (var stream = new MemoryStream(buffer, sizeof(long), buffer.Length - sizeof(long), false))
                     {
-                        image = new BitmapImage();
+                        image = BitmapFrame.Create(stream, BitmapCreateOptions.None, BitmapCacheOption.OnLoad);
-                        image.BeginInit();
-                        image.CacheOption = BitmapCacheOption.OnLoad;
-                        image.StreamSource = stream;
-                        image.EndInit();
-                        image.Freeze();
                     }
                 }
                 catch (Exception ex)
                 {
                     Trace.TraceWarning("Creating tile image failed: {0}", ex.Message);
-                    image = null;
                 }
             }
 
@@ -269,11 +301,6 @@ namespace MapControl
                 var request = (HttpWebRequest)WebRequest.Create(uri);
                 request.UserAgent = "XAML Map Control";
 
-                if (Cache != null)
-                {
-                    request.CachePolicy = new HttpRequestCachePolicy(HttpRequestCacheLevel.NoCacheNoStore);
-                }
-
                 using (var response = (HttpWebResponse)request.GetResponse())
                 using (var responseStream = response.GetResponseStream())
                 {
@@ -289,8 +316,6 @@ namespace MapControl
                         buffer = length > 0 ? memoryStream.GetBuffer() : memoryStream.ToArray();
                     }
                 }
-
-                //Trace.TraceInformation("Downloaded {0}", uri);
             }
             catch (WebException ex)
             {

MapControl/TileLayer.cs

@@ -40,7 +40,7 @@ namespace MapControl
         }
 
         private readonly MatrixTransform transform = new MatrixTransform();
-        private readonly TileImageLoader tileImageLoader;
+        private readonly TileImageLoader tileImageLoader = new TileImageLoader();
         private List<Tile> tiles = new List<Tile>();
         private string description = string.Empty;
         private Int32Rect grid;
@@ -48,7 +48,6 @@ namespace MapControl
 
         public TileLayer()
         {
-            tileImageLoader = new TileImageLoader(this);
             MinZoomLevel = 1;
             MaxZoomLevel = 18;
             MaxParallelDownloads = 8;
@@ -96,7 +95,7 @@ namespace MapControl
             {
                 SelectTiles();
                 RenderTiles();
-                tileImageLoader.StartGetTiles(tiles.Where(t => !t.HasImage));
+                tileImageLoader.BeginGetTiles(this, tiles.Where(t => !t.HasImageSource));
             }
         }
 

MapControl/TileSource.cs

@@ -102,7 +102,7 @@ namespace MapControl
 
         private Uri GetOpenStreetMapUri(int x, int y, int zoomLevel)
         {
-            var hostIndex = (x + y + zoomLevel) % 3;
+            var hostIndex = (x + y) % 3;
 
             return new Uri(UriFormat.
                 Replace("{c}", "abc".Substring(hostIndex, 1)).
@@ -113,7 +113,7 @@ namespace MapControl
 
         private Uri GetGoogleMapsUri(int x, int y, int zoomLevel)
         {
-            var hostIndex = (x + y + zoomLevel) % 4;
+            var hostIndex = (x + y) % 4;
 
             return new Uri(UriFormat.
                 Replace("{i}", hostIndex.ToString()).
@@ -124,7 +124,7 @@ namespace MapControl
 
         private Uri GetMapQuestUri(int x, int y, int zoomLevel)
         {
-            var hostIndex = (x + y + zoomLevel) % 4 + 1;
+            var hostIndex = (x + y) % 4 + 1;
 
             return new Uri(UriFormat.
                 Replace("{n}", hostIndex.ToString()).

MapControl/WinRT/MapControl.WinRT.csproj

@@ -39,8 +39,8 @@
     <Compile Include="..\AnimationEx.WinRT.cs">
       <Link>AnimationEx.WinRT.cs</Link>
     </Compile>
-    <Compile Include="..\Freezable.cs">
+    <Compile Include="..\ImageTileSource.cs">
-      <Link>Freezable.cs</Link>
+      <Link>ImageTileSource.cs</Link>
     </Compile>
     <Compile Include="..\Int32Rect.cs">
       <Link>Int32Rect.cs</Link>

MapControl/WinRT/Properties/AssemblyInfo.cs

@@ -8,8 +8,8 @@ using System.Runtime.InteropServices;
 [assembly: AssemblyCompany("Clemens Fischer")]
 [assembly: AssemblyCopyright("Copyright © Clemens Fischer 2012-2013")]
 [assembly: AssemblyTrademark("")]
-[assembly: AssemblyVersion("1.7.0")]
+[assembly: AssemblyVersion("1.8.0")]
-[assembly: AssemblyFileVersion("1.7.0")]
+[assembly: AssemblyFileVersion("1.8.0")]
 [assembly: AssemblyConfiguration("")]
 [assembly: AssemblyCulture("")]
 [assembly: ComVisible(false)]

SampleApps/SilverlightApplication.Web/Properties/AssemblyInfo.cs

@@ -8,8 +8,8 @@ using System.Runtime.InteropServices;
 [assembly: AssemblyCompany("Clemens Fischer")]
 [assembly: AssemblyCopyright("Copyright © Clemens Fischer 2012-2013")]
 [assembly: AssemblyTrademark("")]
-[assembly: AssemblyVersion("1.7.0")]
+[assembly: AssemblyVersion("1.8.0")]
-[assembly: AssemblyFileVersion("1.7.0")]
+[assembly: AssemblyFileVersion("1.8.0")]
 [assembly: AssemblyConfiguration("")]
 [assembly: AssemblyCulture("")]
 [assembly: ComVisible(false)]

SampleApps/SilverlightApplication/Properties/AssemblyInfo.cs

@@ -8,8 +8,8 @@ using System.Runtime.InteropServices;
 [assembly: AssemblyCompany("Clemens Fischer")]
 [assembly: AssemblyCopyright("Copyright © Clemens Fischer 2012-2013")]
 [assembly: AssemblyTrademark("")]
-[assembly: AssemblyVersion("1.7.0")]
+[assembly: AssemblyVersion("1.8.0")]
-[assembly: AssemblyFileVersion("1.7.0")]
+[assembly: AssemblyFileVersion("1.8.0")]
 [assembly: AssemblyConfiguration("")]
 [assembly: AssemblyCulture("")]
 [assembly: ComVisible(false)]

SampleApps/StoreApplication/Properties/AssemblyInfo.cs

@@ -8,8 +8,8 @@ using System.Runtime.InteropServices;
 [assembly: AssemblyCompany("Clemens Fischer")]
 [assembly: AssemblyCopyright("Copyright © Clemens Fischer 2012-2013")]
 [assembly: AssemblyTrademark("")]
-[assembly: AssemblyVersion("1.7.0")]
+[assembly: AssemblyVersion("1.8.0")]
-[assembly: AssemblyFileVersion("1.7.0")]
+[assembly: AssemblyFileVersion("1.8.0")]
 [assembly: AssemblyConfiguration("")]
 [assembly: AssemblyCulture("")]
 [assembly: ComVisible(false)]

SampleApps/SurfaceApplication/Properties/AssemblyInfo.cs

@@ -8,8 +8,8 @@ using System.Runtime.InteropServices;
 [assembly: AssemblyCompany("Clemens Fischer")]
 [assembly: AssemblyCopyright("Copyright © Clemens Fischer 2012-2013")]
 [assembly: AssemblyTrademark("")]
-[assembly: AssemblyVersion("1.7.0")]
+[assembly: AssemblyVersion("1.8.0")]
-[assembly: AssemblyFileVersion("1.7.0")]
+[assembly: AssemblyFileVersion("1.8.0")]
 [assembly: AssemblyConfiguration("")]
 [assembly: AssemblyCulture("")]
 [assembly: ComVisible(false)]

SampleApps/WpfApplication/MainWindow.xaml.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Globalization;
+using System.Runtime.Caching;
 using System.Windows;
 using System.Windows.Controls;
 using System.Windows.Input;
@@ -22,6 +23,9 @@ namespace WpfApplication
         {
             switch (Properties.Settings.Default.TileCache)
             {
+                case "MemoryCache":
+                    TileImageLoader.Cache = MemoryCache.Default;
+                    break;
                 case "FileDbCache":
                     TileImageLoader.Cache = new FileDbCache(TileImageLoader.DefaultCacheName, TileImageLoader.DefaultCacheDirectory);
                     break;

SampleApps/WpfApplication/Properties/AssemblyInfo.cs

@@ -8,8 +8,8 @@ using System.Runtime.InteropServices;
 [assembly: AssemblyCompany("Clemens Fischer")]
 [assembly: AssemblyCopyright("Copyright © Clemens Fischer 2012-2013")]
 [assembly: AssemblyTrademark("")]
-[assembly: AssemblyVersion("1.7.0")]
+[assembly: AssemblyVersion("1.8.0")]
-[assembly: AssemblyFileVersion("1.7.0")]
+[assembly: AssemblyFileVersion("1.8.0")]
 [assembly: AssemblyConfiguration("")]
 [assembly: AssemblyCulture("")]
 [assembly: ComVisible(false)]