public LoadTileTask(IImageSource imageSource, TileIndex.Full index)
{
this.ImageSource = imageSource;
this.Index = index;
this.Progress.ProgressChanged += this.Progress_ProgressChanged;
}
public static async Task <BitmapSource> ClipAsync(
this IImageSource imageSource,
Int32Rect bounds,
int?layer = null,
int?lodLevel = null,
CancellationToken cancellationToken = default)
{
// ReSharper disable once SuspiciousTypeConversion.Global
if (imageSource is INativeClippable nativeClippable)
{
return(await nativeClippable.ClipAsync(bounds, layer, lodLevel, cancellationToken));
}
var finalLayer = layer ?? imageSource.Dimensions.MinimumLayerIndex;
var finalLodLevel = lodLevel ?? imageSource.LOD.MinLODLevel;
var dimensions = imageSource.GetLODDimensions(finalLodLevel);
var tileWidth = dimensions.TileWidth;
var tileHeight = dimensions.TileHeight;
var tileIndexLeft = bounds.X / tileWidth;
var tileIndexTop = bounds.Y / tileHeight;
var tileIndexRight = (bounds.X + bounds.Width - 1) / tileWidth;
var tileIndexBottom = (bounds.Y + bounds.Height - 1) / tileHeight;
var copyPixelRequests = new List <CopyPixelRequest>();
for (var row = tileIndexTop; row <= tileIndexBottom; ++row)
{
cancellationToken.ThrowIfCancellationRequested();
var tileTop = row * tileHeight;
var tileBottom = (row + 1) * tileHeight;
var copyMetricsY = ImageCopyMetrics.Calculate(tileTop, tileBottom, bounds.Y, bounds.Height);
for (var column = tileIndexLeft; column <= tileIndexRight; ++column)
{
var tileLeft = column * tileWidth;
var tileRight = (column + 1) * tileWidth;
var index = new TileIndex.Full(column, row, finalLayer, finalLodLevel);
var tileImage = await imageSource.LoadTileAsync(index, cancellationToken : cancellationToken);
var copyMetricsX = ImageCopyMetrics.Calculate(tileLeft, tileRight, bounds.X, bounds.Height);
var sourceRect = new Int32Rect(
copyMetricsX.Source,
copyMetricsY.Source,
copyMetricsX.Size,
copyMetricsY.Size);
var destinationRect = new Int32Rect(
copyMetricsX.Destination,
copyMetricsY.Destination,
copyMetricsX.Size,
copyMetricsY.Size);
copyPixelRequests.Add(new CopyPixelRequest(tileImage, sourceRect, destinationRect));
}
}
cancellationToken.ThrowIfCancellationRequested();
var image = new WriteableBitmap(bounds.Width, bounds.Height, 96, 96, PixelFormats.Bgr24, null);
image.ClearBackBuffer();
foreach (var request in copyPixelRequests)
{
cancellationToken.ThrowIfCancellationRequested();
var source = request.TileImage.Format == PixelFormats.Bgr24
? request.TileImage
: new FormatConvertedBitmap(request.TileImage, PixelFormats.Bgr24, null, 0);
source.CopyPixels(
request.SourceRect,
image.BackBuffer + request.DestinationRect.Y * image.BackBufferStride +
request.DestinationRect.X * 3,
image.PixelHeight * image.BackBufferStride,
image.BackBufferStride);
}
image.Freeze();
return(image);
}
