Version 4.10.0: Simplified TileImageLoader.

This commit is contained in:
ClemensF 2018-08-21 23:56:54 +02:00
parent f6135d2bfb
commit be3a247064
6 changed files with 113 additions and 101 deletions

View file

@ -5,7 +5,6 @@
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
#if WINDOWS_UWP
using Windows.Foundation;
using Windows.UI.Xaml;
@ -22,7 +21,7 @@ namespace MapControl
{
public interface ITileImageLoader
{
Task LoadTilesAsync(MapTileLayer tileLayer);
void LoadTilesAsync(MapTileLayer tileLayer);
}
/// <summary>
@ -93,7 +92,6 @@ namespace MapControl
IsHitTestVisible = false;
RenderTransform = new MatrixTransform();
TileImageLoader = tileImageLoader;
Tiles = new List<Tile>();
updateTimer = new DispatcherTimer { Interval = UpdateInterval };
updateTimer.Tick += (s, e) => UpdateTileGrid();
@ -102,9 +100,11 @@ namespace MapControl
}
public ITileImageLoader TileImageLoader { get; private set; }
public ICollection<Tile> Tiles { get; private set; }
public TileGrid TileGrid { get; private set; }
public IReadOnlyCollection<Tile> Tiles { get; private set; } = new List<Tile>();
/// <summary>
/// Provides map tile URIs or images.
/// </summary>
@ -273,7 +273,7 @@ namespace MapControl
{
if (TileGrid != null)
{
Tiles.Clear();
Tiles = new List<Tile>();
UpdateTiles();
}
}
@ -344,9 +344,7 @@ namespace MapControl
var maxZoomLevel = Math.Min(TileGrid.ZoomLevel, MaxZoomLevel);
var minZoomLevel = MinZoomLevel;
if (minZoomLevel < maxZoomLevel &&
parentMap.MapLayer != this &&
parentMap.Children.Cast<UIElement>().FirstOrDefault() != this)
if (minZoomLevel < maxZoomLevel && parentMap.MapLayer != this)
{
minZoomLevel = maxZoomLevel; // do not load lower level tiles if this is note a "base" layer
}
@ -393,7 +391,7 @@ namespace MapControl
Children.Add(tile.Image);
}
var task = TileImageLoader.LoadTilesAsync(this);
TileImageLoader.LoadTilesAsync(this);
}
}
}

View file

@ -18,6 +18,12 @@ namespace MapControl
/// </summary>
public class PolygonCollection : ObservableCollection<IEnumerable<Location>>, IWeakEventListener
{
public bool ReceiveWeakEvent(Type managerType, object sender, EventArgs e)
{
OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Replace, sender, sender));
return true;
}
protected override void InsertItem(int index, IEnumerable<Location> polygon)
{
var observablePolygon = polygon as INotifyCollectionChanged;
@ -63,12 +69,5 @@ namespace MapControl
base.ClearItems();
}
bool IWeakEventListener.ReceiveWeakEvent(Type managerType, object sender, EventArgs e)
{
OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Replace, sender, sender));
return true;
}
}
}

View file

@ -18,20 +18,25 @@ namespace MapControl
public partial class TileImageLoader : ITileImageLoader
{
/// <summary>
/// Default expiration time for cached tile images. Used when no expiration time
/// was transmitted on download. The default value is one day.
/// Maximum number of parallel tile loading tasks. The default value is 4.
/// </summary>
public static TimeSpan DefaultCacheExpiration { get; set; } = TimeSpan.FromDays(1);
public static int MaxLoadTasks { get; set; } = 4;
/// <summary>
/// Minimum expiration time for cached tile images. The default value is one hour.
/// </summary>
public static TimeSpan MinimumCacheExpiration { get; set; } = TimeSpan.FromHours(1);
public static TimeSpan MinCacheExpiration { get; set; } = TimeSpan.FromHours(1);
/// <summary>
/// Maximum expiration time for cached tile images. The default value is one week.
/// </summary>
public static TimeSpan MaximumCacheExpiration { get; set; } = TimeSpan.FromDays(7);
public static TimeSpan MaxCacheExpiration { get; set; } = TimeSpan.FromDays(7);
/// <summary>
/// Default expiration time for cached tile images. Used when no expiration time
/// was transmitted on download. The default value is one day.
/// </summary>
public static TimeSpan DefaultCacheExpiration { get; set; } = TimeSpan.FromDays(1);
/// <summary>
/// Format string for creating cache keys from the SourceName property of a TileSource,
@ -43,7 +48,12 @@ namespace MapControl
private readonly ConcurrentStack<Tile> pendingTiles = new ConcurrentStack<Tile>();
private int taskCount;
public async Task LoadTilesAsync(MapTileLayer tileLayer)
/// <summary>
/// Loads all pending tiles from the Tiles collection of a MapTileLayer by running up to MaxLoadTasks parallel Tasks.
/// If the TileSource's SourceName is non-empty and its UriFormat starts with "http", tile images are cached in the
/// TileImageLoader's Cache.
/// </summary>
public void LoadTilesAsync(MapTileLayer tileLayer)
{
pendingTiles.Clear();
@ -53,55 +63,34 @@ namespace MapControl
if (tileSource != null && tiles.Any())
{
if (Cache == null || string.IsNullOrEmpty(sourceName) ||
tileSource.UriFormat == null || !tileSource.UriFormat.StartsWith("http"))
{
// no caching, load tile images directly
pendingTiles.PushRange(tiles.Reverse().ToArray());
foreach (var tile in tiles)
Func<Tile, Task> loadFunc;
if (Cache != null && !string.IsNullOrEmpty(sourceName) &&
tileSource.UriFormat != null && tileSource.UriFormat.StartsWith("http"))
{
await LoadTileImageAsync(tileSource, tile);
}
loadFunc = tile => LoadCachedTileImageAsync(tile, tileSource, sourceName);
}
else
{
pendingTiles.PushRange(tiles.Reverse().ToArray());
loadFunc = tile => LoadTileImageAsync(tile, tileSource);
}
while (taskCount < Math.Min(pendingTiles.Count, DefaultConnectionLimit))
var maxTasks = Math.Min(pendingTiles.Count, MaxLoadTasks);
while (taskCount < maxTasks)
{
Interlocked.Increment(ref taskCount);
var task = Task.Run(async () => // do not await
{
await LoadPendingTilesAsync(tileSource, sourceName); // run multiple times in parallel
var task = Task.Run(() => LoadTilesAsync(loadFunc)); // do not await
}
Interlocked.Decrement(ref taskCount);
});
}
}
//Debug.WriteLine("{0}: {1} tasks", Environment.CurrentManagedThreadId, taskCount);
}
}
private async Task LoadTileImageAsync(TileSource tileSource, Tile tile)
{
tile.Pending = false;
try
{
var imageSource = await tileSource.LoadImageAsync(tile.XIndex, tile.Y, tile.ZoomLevel);
if (imageSource != null)
{
tile.SetImage(imageSource);
}
}
catch (Exception ex)
{
Debug.WriteLine("TileImageLoader: {0}/{1}/{2}: {3}", tile.ZoomLevel, tile.XIndex, tile.Y, ex.Message);
}
}
private async Task LoadPendingTilesAsync(TileSource tileSource, string sourceName)
private async Task LoadTilesAsync(Func<Tile, Task> loadTileImageFunc)
{
Tile tile;
@ -110,6 +99,20 @@ namespace MapControl
tile.Pending = false;
try
{
await loadTileImageFunc(tile);
}
catch (Exception ex)
{
Debug.WriteLine("TileImageLoader: {0}/{1}/{2}: {3}", tile.ZoomLevel, tile.XIndex, tile.Y, ex.Message);
}
}
Interlocked.Decrement(ref taskCount);
//Debug.WriteLine("{0}: {1} tasks", Environment.CurrentManagedThreadId, taskCount);
}
private async Task LoadCachedTileImageAsync(Tile tile, TileSource tileSource, string sourceName)
{
var uri = tileSource.GetUri(tile.XIndex, tile.Y, tile.ZoomLevel);
@ -124,13 +127,7 @@ namespace MapControl
var cacheKey = string.Format(CacheKeyFormat, sourceName, tile.ZoomLevel, tile.XIndex, tile.Y, extension);
await LoadTileImageAsync(tile, uri, cacheKey);
}
}
catch (Exception ex)
{
Debug.WriteLine("TileImageLoader: {0}/{1}/{2}: {3}", tile.ZoomLevel, tile.XIndex, tile.Y, ex.Message);
}
await LoadCachedTileImageAsync(tile, uri, cacheKey);
}
}
@ -142,13 +139,13 @@ namespace MapControl
{
expiration = maxAge.Value;
if (expiration < MinimumCacheExpiration)
if (expiration < MinCacheExpiration)
{
expiration = MinimumCacheExpiration;
expiration = MinCacheExpiration;
}
else if (expiration > MaximumCacheExpiration)
else if (expiration > MaxCacheExpiration)
{
expiration = MaximumCacheExpiration;
expiration = MaxCacheExpiration;
}
}

View file

@ -26,12 +26,7 @@ namespace MapControl
/// </summary>
public static Caching.IImageCache Cache { get; set; }
/// <summary>
/// Gets or sets the maximum number of concurrent connections. The default value is 2.
/// </summary>
public static int DefaultConnectionLimit { get; set; } = 2;
private async Task LoadTileImageAsync(Tile tile, Uri uri, string cacheKey)
private async Task LoadCachedTileImageAsync(Tile tile, Uri uri, string cacheKey)
{
var cacheItem = await Cache.GetAsync(cacheKey);
var cacheBuffer = cacheItem?.Buffer;
@ -46,7 +41,7 @@ namespace MapControl
if (result.Item1 != null) // tile image available
{
await SetTileImageAsync(tile, result.Item1); // show before caching
await LoadTileImageAsync(tile, result.Item1);
await Cache.SetAsync(cacheKey, result.Item1, GetExpiration(result.Item2));
}
}
@ -54,21 +49,20 @@ namespace MapControl
if (cacheBuffer != null)
{
await SetTileImageAsync(tile, cacheBuffer);
await LoadTileImageAsync(tile, cacheBuffer);
}
}
private async Task SetTileImageAsync(Tile tile, IBuffer buffer)
private async Task LoadTileImageAsync(Tile tile, IBuffer buffer)
{
var tcs = new TaskCompletionSource<object>();
using (var stream = new InMemoryRandomAccessStream())
{
await stream.WriteAsync(buffer);
await stream.FlushAsync(); // necessary?
stream.Seek(0);
await tile.Image.Dispatcher.RunAsync(CoreDispatcherPriority.Normal, async () =>
await tile.Image.Dispatcher.RunAsync(CoreDispatcherPriority.Low, async () =>
{
try
{
@ -84,5 +78,25 @@ namespace MapControl
await tcs.Task;
}
private async Task LoadTileImageAsync(Tile tile, TileSource tileSource)
{
var tcs = new TaskCompletionSource<object>();
await tile.Image.Dispatcher.RunAsync(CoreDispatcherPriority.Low, async () =>
{
try
{
tile.SetImage(await tileSource.LoadImageAsync(tile.XIndex, tile.Y, tile.ZoomLevel));
tcs.SetResult(null);
}
catch (Exception ex)
{
tcs.SetException(ex);
}
});
await tcs.Task;
}
}
}

View file

@ -21,7 +21,7 @@ namespace MapControl
get { return Data; }
}
bool IWeakEventListener.ReceiveWeakEvent(Type managerType, object sender, EventArgs e)
public bool ReceiveWeakEvent(Type managerType, object sender, EventArgs e)
{
UpdateData();
return true;

View file

@ -4,10 +4,11 @@
using System;
using System.IO;
using System.Net;
using System.Runtime.Caching;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Media;
using System.Windows.Threading;
namespace MapControl
{
@ -27,12 +28,7 @@ namespace MapControl
/// </summary>
public static ObjectCache Cache { get; set; } = MemoryCache.Default;
private static int DefaultConnectionLimit
{
get { return ServicePointManager.DefaultConnectionLimit; }
}
private async Task LoadTileImageAsync(Tile tile, Uri uri, string cacheKey)
private async Task LoadCachedTileImageAsync(Tile tile, Uri uri, string cacheKey)
{
DateTime expiration;
var cacheBuffer = GetCachedImage(cacheKey, out expiration);
@ -49,7 +45,7 @@ namespace MapControl
{
using (var stream = result.Item1)
{
SetTileImage(tile, stream); // show before caching
LoadTileImage(tile, stream);
SetCachedImage(cacheKey, stream, GetExpiration(result.Item2));
}
}
@ -60,15 +56,23 @@ namespace MapControl
{
using (var stream = new MemoryStream(cacheBuffer))
{
SetTileImage(tile, stream);
LoadTileImage(tile, stream);
}
}
}
private void SetTileImage(Tile tile, Stream stream)
private async Task LoadTileImageAsync(Tile tile, TileSource tileSource)
{
var imageSource = ImageLoader.LoadImage(stream);
SetTileImage(tile, await tileSource.LoadImageAsync(tile.XIndex, tile.Y, tile.ZoomLevel));
}
private void LoadTileImage(Tile tile, Stream stream)
{
SetTileImage(tile, ImageLoader.LoadImage(stream));
}
private void SetTileImage(Tile tile, ImageSource imageSource)
{
tile.Image.Dispatcher.InvokeAsync(() => tile.SetImage(imageSource));
}