private async Task LoadPendingTiles(TileQueue tileQueue, TileSource tileSource, string cacheName)
{
while (tileQueue.TryDequeue(out var tile))
{
try
{
await LoadTile(tile, tileSource, cacheName).ConfigureAwait(false);
}
catch (Exception ex)
{
Debug.WriteLine($"TileImageLoader: {tile.ZoomLevel}/{tile.XIndex}/{tile.Y}: {ex.Message}");
}
if (Progress != null && !tileQueue.IsCanceled)
{
Interlocked.Increment(ref progressLoaded);
Progress.Report((double)progressLoaded / progressTotal);
}
}
}
/// <summary>
/// Loads all pending tiles from the tiles collection.
/// If tileSource.UriFormat starts with "http" and cacheName is a non-empty string,
/// tile images will be cached in the TileImageLoader's Cache - if that is not null.
/// </summary>
public Task LoadTiles(IEnumerable <Tile> tiles, TileSource tileSource, string cacheName)
{
pendingTiles?.Cancel();
TileSource = tileSource;
if (tileSource != null)
{
pendingTiles = new TileQueue(tiles);
var numTasks = Math.Min(pendingTiles.Count, MaxLoadTasks);
if (numTasks > 0)
{
if (Progress != null)
{
progressTotal = pendingTiles.Count;
progressLoaded = 0;
Progress.Report(0d);
}
if (Cache == null || tileSource.UriTemplate == null || !tileSource.UriTemplate.StartsWith("http"))
{
cacheName = null; // no tile caching
}
return(Task.WhenAll(Enumerable.Range(0, numTasks).Select(
_ => Task.Run(() => LoadPendingTiles(pendingTiles, tileSource, cacheName)))));
}
}
if (Progress != null && progressLoaded < progressTotal)
{
Progress.Report(1d);
}
return(Task.CompletedTask);
}
