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Version 4.12.2 Improved ImageLoader/TileImageLoader

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This commit is contained in:
ClemensF 2019-07-13 19:53:03 +02:00
parent 4a7e384152
commit fefc4e3294
9 changed files with 102 additions and 171 deletions
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2
MapControl/WPF/ImageFileCache.WPF.cs
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@ -107,6 +107,7 @@ namespace MapControl.Caching
try
{
//Debug.WriteLine("ImageFileCache: Reading " + path);
buffer = File.ReadAllBytes(path);
memoryCache.Set(key, buffer, new CacheItemPolicy());
}
@ -160,6 +161,7 @@ namespace MapControl.Caching
try
{
//Debug.WriteLine("ImageFileCache: Writing {0}, Expires {1}", path, policy.AbsoluteExpiration.DateTime.ToLocalTime());
Directory.CreateDirectory(Path.GetDirectoryName(path));
File.WriteAllBytes(path, buffer);

50
MapControl/WPF/TileImageLoader.WPF.cs
View file

@ -30,40 +30,27 @@ namespace MapControl
private static async Task LoadCachedTileImageAsync(Tile tile, Uri uri, string cacheKey)
{
ImageSource image = null;
DateTime expiration;
byte[] cacheBuffer;
var buffer = GetCachedImage(cacheKey, out expiration);
GetCachedImage(cacheKey, out cacheBuffer, out expiration);
if (cacheBuffer == null || expiration < DateTime.UtcNow)
if (buffer == null || expiration < DateTime.UtcNow)
{
var response = await ImageLoader.GetHttpResponseAsync(uri, false).ConfigureAwait(false);
if (response != null) // download succeeded
{
cacheBuffer = null; // discard cached image
buffer = response.Buffer;
if (response.Stream != null) // tile image available
if (buffer != null) // tile image available
{
using (var stream = response.Stream)
{
image = ImageLoader.LoadImage(stream);
SetCachedImage(cacheKey, stream, GetExpiration(response.MaxAge));
}
await SetCachedImage(cacheKey, buffer, GetExpiration(response.MaxAge)).ConfigureAwait(false);
}
}
}
if (cacheBuffer != null) // cached image not expired or download failed
if (buffer != null)
{
image = ImageLoader.LoadImage(cacheBuffer);
}
if (image != null)
{
SetTileImage(tile, image);
SetTileImageAsync(tile, await ImageLoader.LoadImageAsync(buffer).ConfigureAwait(false));
}
}
@ -73,18 +60,18 @@ namespace MapControl
if (image != null)
{
SetTileImage(tile, image);
SetTileImageAsync(tile, image);
}
}
private static void SetTileImage(Tile tile, ImageSource image)
private static void SetTileImageAsync(Tile tile, ImageSource image)
{
tile.Image.Dispatcher.InvokeAsync(() => tile.SetImage(image));
}
private static void GetCachedImage(string cacheKey, out byte[] buffer, out DateTime expiration)
private static byte[] GetCachedImage(string cacheKey, out DateTime expiration)
{
buffer = Cache.Get(cacheKey) as byte[];
var buffer = Cache.Get(cacheKey) as byte[];
if (buffer != null && buffer.Length >= 16 &&
Encoding.ASCII.GetString(buffer, buffer.Length - 16, 8) == "EXPIRES:")
@ -95,15 +82,20 @@ namespace MapControl
{
expiration = DateTime.MinValue;
}
return buffer;
}
private static void SetCachedImage(string cacheKey, MemoryStream stream, DateTime expiration)
private static async Task SetCachedImage(string cacheKey, byte[] buffer, DateTime expiration)
{
stream.Seek(0, SeekOrigin.End);
stream.Write(Encoding.ASCII.GetBytes("EXPIRES:"), 0, 8);
stream.Write(BitConverter.GetBytes(expiration.Ticks), 0, 8);
using (var stream = new MemoryStream(buffer.Length + 16))
{
await stream.WriteAsync(buffer, 0, buffer.Length).ConfigureAwait(false);
await stream.WriteAsync(Encoding.ASCII.GetBytes("EXPIRES:"), 0, 8).ConfigureAwait(false);
await stream.WriteAsync(BitConverter.GetBytes(expiration.Ticks), 0, 8).ConfigureAwait(false);
Cache.Set(cacheKey, stream.ToArray(), new CacheItemPolicy { AbsoluteExpiration = expiration });
Cache.Set(cacheKey, stream.ToArray(), new CacheItemPolicy { AbsoluteExpiration = expiration });
}
}
}
}