public void Decoder_PixelBufferComparison <TPixel>(TestImageProvider <TPixel> provider)
where TPixel : unmanaged, IPixel <TPixel>
{
// Stream
byte[] sourceBytes = TestFile.Create(provider.SourceFileOrDescription).Bytes;
using var ms = new MemoryStream(sourceBytes);
using var bufferedStream = new BufferedReadStream(Configuration.Default, ms);
// Decoding
using var converter = new SpectralConverter <TPixel>(Configuration.Default);
using var decoder = new JpegDecoderCore(Configuration.Default, new JpegDecoder());
var scanDecoder = new HuffmanScanDecoder(bufferedStream, converter, cancellationToken: default);
decoder.ParseStream(bufferedStream, scanDecoder, cancellationToken: default);
// Test metadata
provider.Utility.TestGroupName = nameof(JpegDecoderTests);
provider.Utility.TestName = JpegDecoderTests.DecodeBaselineJpegOutputName;
// Comparison
using (Image <TPixel> image = new Image <TPixel>(Configuration.Default, converter.GetPixelBuffer(CancellationToken.None), new ImageMetadata()))
using (Image <TPixel> referenceImage = provider.GetReferenceOutputImage <TPixel>(appendPixelTypeToFileName: false))
{
ImageSimilarityReport report = ImageComparer.Exact.CompareImagesOrFrames(referenceImage, image);
this.Output.WriteLine($"*** {provider.SourceFileOrDescription} ***");
this.Output.WriteLine($"Difference: {report.DifferencePercentageString}");
// ReSharper disable once PossibleInvalidOperationException
Assert.True(report.TotalNormalizedDifference.Value < 0.005f);
}
}
/// <inheritdoc/>
public Image <TPixel> Decode <TPixel>(BufferedReadStream stream, CancellationToken cancellationToken)
where TPixel : unmanaged, IPixel <TPixel>
{
using var spectralConverter = new SpectralConverter <TPixel>(this.Configuration, cancellationToken);
var scanDecoder = new HuffmanScanDecoder(stream, spectralConverter, cancellationToken);
this.ParseStream(stream, scanDecoder, cancellationToken);
this.InitExifProfile();
this.InitIccProfile();
this.InitIptcProfile();
this.InitDerivedMetadataProperties();
return(new Image <TPixel>(this.Configuration, spectralConverter.GetPixelBuffer(), this.Metadata));
}
/// <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());
// 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) : new SpectralConverter <Rgb24>(this.configuration);
var scanDecoder = new HuffmanScanDecoder(stream, spectralConverter, CancellationToken.None);
jpegDecoder.LoadTables(this.jpegTables, scanDecoder);
scanDecoder.ResetInterval = 0;
jpegDecoder.ParseStream(stream, scanDecoder, CancellationToken.None);
// TODO: Should we pass through the CancellationToken from the tiff decoder?
CopyImageBytesToBuffer(buffer, spectralConverter.GetPixelBuffer(CancellationToken.None));
}
else
{
using var image = Image.Load <Rgb24>(stream);
CopyImageBytesToBuffer(buffer, image.Frames.RootFrame.PixelBuffer);
}
}