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Version 4.12.2 Improved ImageLoader/TileImageLoader

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This commit is contained in:
ClemensF 2019-07-13 08:49:49 +02:00
parent 25bdf3050b
commit 4a7e384152
4 changed files with 54 additions and 57 deletions
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73
MapControl/Shared/ImageLoader.cs
View file

@ -8,7 +8,6 @@ using System.Diagnostics;
using System.Linq;
using System.IO;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Threading.Tasks;
#if WINDOWS_UWP
using Windows.UI.Xaml.Media;
@ -23,10 +22,11 @@ namespace MapControl
public static partial class ImageLoader
{
/// <summary>
/// The HttpClient instance used when image data is downloaded from a web resource.
/// The System.Net.Http.HttpClient instance used when image data is downloaded via a http or https Uri.
/// </summary>
public static HttpClient HttpClient { get; set; } = new HttpClient();
public static async Task<ImageSource> LoadImageAsync(Uri uri)
{
ImageSource image = null;
@ -39,24 +39,13 @@ namespace MapControl
}
else if (uri.Scheme == "http" || uri.Scheme == "https")
{
using (var response = await HttpClient.GetAsync(uri))
{
if (response.IsSuccessStatusCode)
{
if (ImageAvailable(response.Headers))
{
using (var stream = new MemoryStream())
{
await response.Content.CopyToAsync(stream);
stream.Seek(0, SeekOrigin.Begin);
var response = await GetHttpResponseAsync(uri);
image = await LoadImageAsync(stream);
}
}
}
else
if (response?.Stream != null)
{
using (var stream = response.Stream)
{
Debug.WriteLine("ImageLoader: {0}: {1} {2}", uri, (int)response.StatusCode, response.ReasonPhrase);
image = await LoadImageAsync(stream);
}
}
}
@ -73,34 +62,21 @@ namespace MapControl
return image;
}
internal class ImageStream : MemoryStream
internal static async Task<HttpResponse> GetHttpResponseAsync(Uri uri, bool continueOnCapturedContext = true)
{
public TimeSpan? MaxAge { get; set; }
}
internal static async Task<ImageStream> LoadImageStreamAsync(Uri uri)
{
ImageStream stream = null;
HttpResponse response = null;
try
{
using (var response = await HttpClient.GetAsync(uri).ConfigureAwait(false))
using (var responseMessage = await HttpClient.GetAsync(uri).ConfigureAwait(continueOnCapturedContext))
{
if (response.IsSuccessStatusCode)
if (responseMessage.IsSuccessStatusCode)
{
stream = new ImageStream();
if (ImageAvailable(response.Headers))
{
await response.Content.CopyToAsync(stream).ConfigureAwait(false);
stream.Seek(0, SeekOrigin.Begin);
stream.MaxAge = response.Headers.CacheControl?.MaxAge;
}
response = await HttpResponse.Create(responseMessage, continueOnCapturedContext);
}
else
{
Debug.WriteLine("ImageLoader: {0}: {1} {2}", uri, (int)response.StatusCode, response.ReasonPhrase);
Debug.WriteLine("ImageLoader: {0}: {1} {2}", uri, (int)responseMessage.StatusCode, responseMessage.ReasonPhrase);
}
}
}
@ -109,14 +85,29 @@ namespace MapControl
Debug.WriteLine("ImageLoader: {0}: {1}", uri, ex.Message);
}
return stream;
return response;
}
private static bool ImageAvailable(HttpResponseHeaders responseHeaders)
internal class HttpResponse
{
IEnumerable<string> tileInfo;
public MemoryStream Stream { get; private set; }
public TimeSpan? MaxAge { get; private set; }
return !responseHeaders.TryGetValues("X-VE-Tile-Info", out tileInfo) || !tileInfo.Contains("no-tile");
internal static async Task<HttpResponse> Create(HttpResponseMessage message, bool continueOnCapturedContext)
{
var response = new HttpResponse();
IEnumerable<string> tileInfo;
if (!message.Headers.TryGetValues("X-VE-Tile-Info", out tileInfo) || !tileInfo.Contains("no-tile"))
{
response.Stream = new MemoryStream();
await message.Content.CopyToAsync(response.Stream).ConfigureAwait(continueOnCapturedContext);
response.Stream.Seek(0, SeekOrigin.Begin);
response.MaxAge = message.Headers.CacheControl?.MaxAge;
}
return response;
}
}
}
}

6
MapControl/Shared/TileImageLoader.cs
View file

@ -107,6 +107,8 @@ namespace MapControl
try
{
Debug.WriteLine("TileImageLoader: loading {0}/{1}/{2} in thread {3}", tile.ZoomLevel, tile.XIndex, tile.Y, Environment.CurrentManagedThreadId);
await loadTileImage(tile).ConfigureAwait(false);
}
catch (Exception ex)
@ -125,7 +127,7 @@ namespace MapControl
tileSource.UriFormat.StartsWith("http") &&
!string.IsNullOrEmpty(sourceName))
{
loadTileImage = tile => LoadTileImageAsync(tile, tileSource, sourceName);
loadTileImage = tile => LoadCachedTileImageAsync(tile, tileSource, sourceName);
}
else
{
@ -133,7 +135,7 @@ namespace MapControl
}
}
private static async Task LoadTileImageAsync(Tile tile, TileSource tileSource, string sourceName)
private static async Task LoadCachedTileImageAsync(Tile tile, TileSource tileSource, string sourceName)
{
var uri = tileSource.GetUri(tile.XIndex, tile.Y, tile.ZoomLevel);

16
MapControl/UWP/TileImageLoader.UWP.cs
View file

@ -36,17 +36,19 @@ namespace MapControl
if (cacheBuffer == null || cacheItem.Expiration < DateTime.UtcNow)
{
using (var stream = await ImageLoader.LoadImageStreamAsync(uri).ConfigureAwait(false))
{
if (stream != null) // download succeeded
{
cacheBuffer = null; // discard cached image
var response = await ImageLoader.GetHttpResponseAsync(uri, false).ConfigureAwait(false);
if (stream.Length > 0) // tile image available
if (response != null) // download succeeded
{
cacheBuffer = null; // discard cached image
if (response.Stream != null) // tile image available
{
using (var stream = response.Stream)
{
await SetTileImageAsync(tile, () => ImageLoader.LoadImageAsync(stream)).ConfigureAwait(false);
await Cache.SetAsync(cacheKey, stream.ToArray().AsBuffer(), GetExpiration(stream.MaxAge)).ConfigureAwait(false);
await Cache.SetAsync(cacheKey, stream.ToArray().AsBuffer(), GetExpiration(response.MaxAge)).ConfigureAwait(false);
}
}
}

16
MapControl/WPF/TileImageLoader.WPF.cs
View file

@ -38,17 +38,19 @@ namespace MapControl
if (cacheBuffer == null || expiration < DateTime.UtcNow)
{
using (var stream = await ImageLoader.LoadImageStreamAsync(uri).ConfigureAwait(false))
{
if (stream != null) // download succeeded
{
cacheBuffer = null; // discard cached image
var response = await ImageLoader.GetHttpResponseAsync(uri, false).ConfigureAwait(false);
if (stream.Length > 0) // tile image available
if (response != null) // download succeeded
{
cacheBuffer = null; // discard cached image
if (response.Stream != null) // tile image available
{
using (var stream = response.Stream)
{
image = ImageLoader.LoadImage(stream);
SetCachedImage(cacheKey, stream, GetExpiration(stream.MaxAge));
SetCachedImage(cacheKey, stream, GetExpiration(response.MaxAge));
}
}
}