Added WorldMercatorProjection, fixed bounding box problems when changing projection.

MapControl/UWP/ImageLoader.UWP.cs

@@ -0,0 +1,110 @@
+// XAML Map Control - https://github.com/ClemensFischer/XAML-Map-Control
+// © 2017 Clemens Fischer
+// Licensed under the Microsoft Public License (Ms-PL)
+
+using System;
+using System.Diagnostics;
+using System.IO;
+using System.Threading.Tasks;
+using Windows.Storage;
+using Windows.Storage.Streams;
+using Windows.UI.Xaml.Media;
+using Windows.UI.Xaml.Media.Imaging;
+using Windows.Web.Http;
+using Windows.Web.Http.Headers;
+
+namespace MapControl
+{
+    public static class ImageLoader
+    {
+        /// <summary>
+        /// The HttpClient instance used when image data is downloaded from a web resource.
+        /// </summary>
+        public static HttpClient HttpClient { get; set; } = new HttpClient();
+
+        public static async Task<ImageSource> LoadImageAsync(Uri uri, bool isTileImage)
+        {
+            if (!uri.IsAbsoluteUri || uri.Scheme == "file")
+            {
+                return await LoadLocalImageAsync(uri);
+            }
+
+            if (uri.Scheme == "http")
+            {
+                return await LoadHttpImageAsync(uri, isTileImage);
+            }
+
+            return new BitmapImage(uri);
+        }
+
+        public static async Task<ImageSource> LoadLocalImageAsync(Uri uri)
+        {
+            var path = uri.IsAbsoluteUri ? uri.LocalPath : uri.OriginalString;
+
+            if (!await Task.Run(() => File.Exists(path)))
+            {
+                return null;
+            }
+
+            var file = await StorageFile.GetFileFromPathAsync(path);
+
+            using (var stream = await file.OpenReadAsync())
+            {
+                var bitmapImage = new BitmapImage();
+                await bitmapImage.SetSourceAsync(stream);
+
+                return bitmapImage;
+            }
+        }
+
+        public static async Task<ImageSource> LoadHttpImageAsync(Uri uri, bool isTileImage)
+        {
+            using (var response = await HttpClient.GetAsync(uri))
+            {
+                if (!response.IsSuccessStatusCode)
+                {
+                    Debug.WriteLine("ImageLoader: {0}: {1} {2}", uri, (int)response.StatusCode, response.ReasonPhrase);
+                }
+                else if (!isTileImage || IsTileAvailable(response.Headers))
+                {
+                    using (var stream = new InMemoryRandomAccessStream())
+                    {
+                        await response.Content.WriteToStreamAsync(stream);
+                        stream.Seek(0);
+
+                        var bitmapImage = new BitmapImage();
+                        await bitmapImage.SetSourceAsync(stream);
+
+                        return bitmapImage;
+                    }
+                }
+
+                return null;
+            }
+        }
+
+        public static async Task<bool> LoadHttpTileImageAsync(Uri uri, Func<IBuffer, TimeSpan?, Task> tileCallback)
+        {
+            using (var response = await HttpClient.GetAsync(uri))
+            {
+                if (!response.IsSuccessStatusCode)
+                {
+                    Debug.WriteLine("ImageLoader: {0}: {1} {2}", uri, (int)response.StatusCode, response.ReasonPhrase);
+                }
+                else if (IsTileAvailable(response.Headers))
+                {
+                    var buffer = await response.Content.ReadAsBufferAsync();
+
+                    await tileCallback(buffer, response.Headers.CacheControl?.MaxAge);
+                }
+
+                return response.IsSuccessStatusCode;
+            }
+        }
+
+        private static bool IsTileAvailable(HttpResponseHeaderCollection responseHeaders)
+        {
+            return !responseHeaders.TryGetValue("X-VE-Tile-Info", out string tileInfo) || tileInfo != "no-tile";
+        }
+    }
+}