/// <inheritdoc/>
protected override void Decompress(BufferedReadStream stream, int byteCount, int stripHeight, Span <byte> buffer)
{
if (this.jpegTables != null)
{
using var jpegDecoder = new JpegDecoderCore(this.configuration, new JpegDecoder());
// TODO: Should we pass through the CancellationToken from the tiff decoder?
// If the PhotometricInterpretation is YCbCr we explicitly assume the JPEG data is in RGB color space.
// There seems no other way to determine that the JPEG data is RGB colorspace (no APP14 marker, componentId's are not RGB).
using SpectralConverter <Rgb24> spectralConverter = this.photometricInterpretation == TiffPhotometricInterpretation.YCbCr ?
new RgbJpegSpectralConverter <Rgb24>(this.configuration, CancellationToken.None) : new SpectralConverter <Rgb24>(this.configuration, CancellationToken.None);
var scanDecoder = new HuffmanScanDecoder(stream, spectralConverter, CancellationToken.None);
jpegDecoder.LoadTables(this.jpegTables, scanDecoder);
scanDecoder.ResetInterval = 0;
jpegDecoder.ParseStream(stream, scanDecoder, CancellationToken.None);
using var image = new Image <Rgb24>(this.configuration, spectralConverter.PixelBuffer, new ImageMetadata());
CopyImageBytesToBuffer(buffer, image);
}
else
{
using var image = Image.Load <Rgb24>(stream);
CopyImageBytesToBuffer(buffer, image);
}
}