/// <summary>
/// Crop a sub region from <paramref name="reader"/>.
/// </summary>
/// <typeparam name="TPixel">The pixel type.</typeparam>
/// <param name="reader">The original pixel buffer.</param>
/// <param name="offset">The number of columns and rows to skip.</param>
/// <param name="size">The number of columns and rows to take.</param>
/// <returns>A <see cref="TiffPixelBuffer{TPixel}"/> representing the cropped region.</returns>
public static TiffPixelBufferReader <TPixel> Crop <TPixel>(this ITiffPixelBufferReader <TPixel> reader, TiffPoint offset, TiffSize size) where TPixel : unmanaged
{
if (reader is TiffPixelBufferReader <TPixel> structReader)
{
return(structReader.Crop(offset, size));
}
return(reader.AsPixelBufferReader().Crop(offset, size));
}
/// <inheritdoc />
public override async Task <TiffStreamRegion> EncodeAsync(TiffFileWriter writer, TiffPoint offset, TiffSize size, ITiffPixelBufferReader <TPixel> reader, CancellationToken cancellationToken)
{
if (writer is null)
{
throw new ArgumentNullException(nameof(writer));
}
if (reader is null)
{
throw new ArgumentNullException(nameof(reader));
}
if (_imageEncoder is null)
{
throw new InvalidOperationException("Image encoder is not configured.");
}
TiffPixelBufferReader <TPixel> structReader = reader.AsPixelBufferReader();
size = new TiffSize(Math.Max(0, Math.Min(structReader.Width - offset.X, size.Width)), Math.Max(0, Math.Min(structReader.Height - offset.Y, size.Height)));
if (size.IsAreaEmpty)
{
throw new ArgumentOutOfRangeException(nameof(size), "The image size is zero.");
}
var context = new TiffDefaultImageEncoderContext <TPixel>
{
MemoryPool = _memoryPool ?? MemoryPool <byte> .Shared,
CancellationToken = cancellationToken,
FileWriter = writer,
ImageSize = size,
PixelConverterFactory = TiffDefaultPixelConverterFactory.Instance,
PixelBufferReader = structReader
};
await _imageEncoder.RunAsync(context).ConfigureAwait(false);
return(context.OutputRegion);
}
