/// <inheritdoc />
public ValueTask InvokeAsync(TiffImageDecoderContext context, ITiffImageDecoderPipelineNode next)
{
if (context is null)
{
throw new ArgumentNullException(nameof(context));
}
if (next is null)
{
throw new ArgumentNullException(nameof(next));
}
TiffYCbCrConverter8 converter = _converter;
int bytesPerScanline = 3 * context.SourceImageSize.Width;
Memory <byte> source = context.UncompressedData.Slice(context.SourceReadOffset.Y * bytesPerScanline);
ReadOnlySpan <byte> sourceSpan = source.Span;
using TiffPixelBufferWriter <TiffRgba32> writer = context.GetWriter <TiffRgba32>();
int rows = context.ReadSize.Height;
int cols = context.ReadSize.Width;
for (int row = 0; row < rows; row++)
{
using TiffPixelSpanHandle <TiffRgba32> pixelSpanHandle = writer.GetRowSpan(row);
ReadOnlySpan <byte> rowSourceSpan = sourceSpan.Slice(3 * context.SourceReadOffset.X, 3 * context.ReadSize.Width);
Span <TiffRgba32> rowDestinationSpan = pixelSpanHandle.GetSpan();
converter.ConvertToRgba32(rowSourceSpan, rowDestinationSpan, cols);
sourceSpan = sourceSpan.Slice(bytesPerScanline);
}
return(next.RunAsync(context));
}
/// <summary>
/// Initialize the middleware.
/// </summary>
/// <param name="coefficients">The YCbCrCoefficients tag.</param>
/// <param name="referenceBlackWhite">The ReferenceBlackWhite tag.</param>
public TiffChunkyYCbCr888Interpreter(TiffValueCollection <TiffRational> coefficients, TiffValueCollection <TiffRational> referenceBlackWhite)
{
if (!coefficients.IsEmpty && coefficients.Count != 3)
{
throw new ArgumentException("coefficient should have 3 none-zero elements.");
}
if (!referenceBlackWhite.IsEmpty && referenceBlackWhite.Count != 6)
{
throw new ArgumentException("referenceWhiteBlack should have 6 elements.");
}
_converter = TiffYCbCrConverter8.Create(coefficients.GetOrCreateArray(), referenceBlackWhite.GetOrCreateArray());
}
/// <inheritdoc />
public ValueTask InvokeAsync(TiffImageDecoderContext context, ITiffImageDecoderPipelineNode next)
{
if (context is null)
{
throw new ArgumentNullException(nameof(context));
}
if (next is null)
{
throw new ArgumentNullException(nameof(next));
}
TiffYCbCrConverter8 converter = _converter;
int skippedRowOffset = context.SourceImageSize.Width * context.SourceReadOffset.Y;
int planarByteCount = context.SourceImageSize.Width * context.SourceImageSize.Height;
ReadOnlySpan <byte> sourceSpan = context.UncompressedData.Span;
ReadOnlySpan <byte> sourceY = sourceSpan.Slice(0, planarByteCount);
ReadOnlySpan <byte> sourceCb = sourceSpan.Slice(planarByteCount, planarByteCount);
ReadOnlySpan <byte> sourceCr = sourceSpan.Slice(2 * planarByteCount, planarByteCount);
using TiffPixelBufferWriter <TiffRgba32> writer = context.GetWriter <TiffRgba32>();
int rows = context.ReadSize.Height;
int cols = context.ReadSize.Width;
for (int row = 0; row < rows; row++)
{
using TiffPixelSpanHandle <TiffRgba32> pixelSpanHandle = writer.GetRowSpan(row);
Span <TiffRgba32> rowDestinationSpan = pixelSpanHandle.GetSpan();
int rowOffset = skippedRowOffset + row * context.SourceImageSize.Width + context.SourceReadOffset.X;
for (int col = 0; col < cols; col++)
{
int componentOffset = rowOffset + col;
rowDestinationSpan[col] = converter.ConvertToRgba32(sourceY[componentOffset], sourceCb[componentOffset], sourceCr[componentOffset]);
}
}
return(next.RunAsync(context));
}
