/// <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));
}
Span <ushort> bitsPerSample = stackalloc ushort[3];
_bitsPerSample.CopyTo(bitsPerSample);
bool isHigherOrderBitsFirst = _fillOrder != TiffFillOrder.LowerOrderBitsFirst;
int totalBitsPerSample = bitsPerSample[0] + bitsPerSample[1] + bitsPerSample[2];
int bytesPerScanline = (context.SourceImageSize.Width * totalBitsPerSample + 7) / 8;
Memory <byte> source = context.UncompressedData.Slice(context.SourceReadOffset.Y * bytesPerScanline);
ReadOnlySpan <byte> sourceSpan = source.Span;
using TiffPixelBufferWriter <TiffRgba64> writer = context.GetWriter <TiffRgba64>();
int rows = context.ReadSize.Height;
int cols = context.ReadSize.Width;
// BitReader.Read reads bytes in big-endian way, we only need to reverse the endianness if the source is little-endian.
bool isLittleEndian = context.IsLittleEndian;
bool reverseEndiannessR = isLittleEndian && bitsPerSample[0] % 8 == 0;
bool reverseEndiannessG = isLittleEndian && bitsPerSample[1] % 8 == 0;
bool reverseEndiannessB = isLittleEndian && bitsPerSample[2] % 8 == 0;
bool canDoFastPath = bitsPerSample[0] >= 16 && bitsPerSample[1] >= 16 && bitsPerSample[2] >= 16 &&
!reverseEndiannessR & !reverseEndiannessG & !reverseEndiannessB;
TiffRgba64 pixel = default;
pixel.A = ushort.MaxValue;
for (int row = 0; row < rows; row++)
{
using TiffPixelSpanHandle <TiffRgba64> pixelSpanHandle = writer.GetRowSpan(row);
Span <TiffRgba64> pixelSpan = pixelSpanHandle.GetSpan();
var bitReader = new BitReader(sourceSpan.Slice(0, bytesPerScanline), isHigherOrderBitsFirst);
bitReader.Advance(context.SourceReadOffset.X * totalBitsPerSample);
if (canDoFastPath)
{
// Fast path for bits >= 8
for (int col = 0; col < cols; col++)
{
pixel.R = (ushort)(FastExpandBits(bitReader.Read(bitsPerSample[0]), bitsPerSample[0], 32) >> 16);
pixel.G = (ushort)(FastExpandBits(bitReader.Read(bitsPerSample[1]), bitsPerSample[1], 32) >> 16);
pixel.B = (ushort)(FastExpandBits(bitReader.Read(bitsPerSample[2]), bitsPerSample[2], 32) >> 16);
pixelSpan[col] = pixel;
}
}
else
{
// Slow path
for (int col = 0; col < cols; col++)
{
pixel.R = (ushort)(ExpandBits(bitReader.Read(bitsPerSample[0]), bitsPerSample[0], 32, reverseEndiannessR) >> 16);
pixel.G = (ushort)(ExpandBits(bitReader.Read(bitsPerSample[1]), bitsPerSample[1], 32, reverseEndiannessG) >> 16);
pixel.B = (ushort)(ExpandBits(bitReader.Read(bitsPerSample[2]), bitsPerSample[2], 32, reverseEndiannessB) >> 16);
pixelSpan[col] = pixel;
}
}
sourceSpan = sourceSpan.Slice(bytesPerScanline);
}
return(next.RunAsync(context));
}
/// <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));
}
Span <ushort> bitsPerSample = stackalloc ushort[3];
_bitsPerSample.CopyTo(bitsPerSample);
bool isHigherOrderBitsFirst = _fillOrder != TiffFillOrder.LowerOrderBitsFirst;
bool canDoFastPath = bitsPerSample[0] >= 4 && bitsPerSample[1] >= 4 && bitsPerSample[2] >= 4;
int totalBitsPerSample = bitsPerSample[0] + bitsPerSample[1] + bitsPerSample[2];
int bytesPerScanline = (context.SourceImageSize.Width * totalBitsPerSample + 7) / 8;
Memory <byte> source = context.UncompressedData.Slice(context.SourceReadOffset.Y * bytesPerScanline);
ReadOnlySpan <byte> sourceSpan = source.Span;
using TiffPixelBufferWriter <TiffRgb24> writer = context.GetWriter <TiffRgb24>();
int rows = context.ReadSize.Height;
int cols = context.ReadSize.Width;
TiffRgb24 pixel = default;
for (int row = 0; row < rows; row++)
{
using TiffPixelSpanHandle <TiffRgb24> pixelSpanHandle = writer.GetRowSpan(row);
Span <TiffRgb24> pixelSpan = pixelSpanHandle.GetSpan();
var bitReader = new BitReader(sourceSpan.Slice(0, bytesPerScanline), isHigherOrderBitsFirst);
bitReader.Advance(context.SourceReadOffset.X * totalBitsPerSample);
if (canDoFastPath)
{
// Fast path for bits >= 8
for (int col = 0; col < cols; col++)
{
pixel.R = (byte)FastExpandBits(bitReader.Read(bitsPerSample[0]), bitsPerSample[0], 8);
pixel.G = (byte)FastExpandBits(bitReader.Read(bitsPerSample[1]), bitsPerSample[1], 8);
pixel.B = (byte)FastExpandBits(bitReader.Read(bitsPerSample[2]), bitsPerSample[2], 8);
pixelSpan[col] = pixel;
}
}
else
{
// Slow path
for (int col = 0; col < cols; col++)
{
pixel.R = (byte)ExpandBits(bitReader.Read(bitsPerSample[0]), bitsPerSample[0], 8);
pixel.G = (byte)ExpandBits(bitReader.Read(bitsPerSample[1]), bitsPerSample[1], 8);
pixel.B = (byte)ExpandBits(bitReader.Read(bitsPerSample[2]), bitsPerSample[2], 8);
pixelSpan[col] = pixel;
}
}
sourceSpan = sourceSpan.Slice(bytesPerScanline);
}
return(next.RunAsync(context));
}
/// <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));
}
Span <ushort> bitsPerSample = stackalloc ushort[4];
_bitsPerSample.CopyTo(bitsPerSample);
bool isHigherOrderBitsFirst = _fillOrder != TiffFillOrder.LowerOrderBitsFirst;
int bytesPerScanlineR = (context.SourceImageSize.Width * bitsPerSample[0] + 7) / 8;
int bytesPerScanlineG = (context.SourceImageSize.Width * bitsPerSample[1] + 7) / 8;
int bytesPerScanlineB = (context.SourceImageSize.Width * bitsPerSample[2] + 7) / 8;
int bytesPerScanlineA = (context.SourceImageSize.Width * bitsPerSample[3] + 7) / 8;
ReadOnlySpan <byte> sourceSpan = context.UncompressedData.Span;
ReadOnlySpan <byte> sourceR = sourceSpan.Slice(0, context.SourceImageSize.Height * bytesPerScanlineR);
ReadOnlySpan <byte> sourceG = sourceSpan.Slice(sourceR.Length, context.SourceImageSize.Height * bytesPerScanlineG);
ReadOnlySpan <byte> sourceB = sourceSpan.Slice(sourceR.Length + sourceG.Length, context.SourceImageSize.Height * bytesPerScanlineB);
ReadOnlySpan <byte> sourceA = sourceSpan.Slice(sourceR.Length + sourceG.Length + sourceB.Length, context.SourceImageSize.Height * bytesPerScanlineA);
sourceR = sourceR.Slice(context.SourceReadOffset.Y * bytesPerScanlineR);
sourceG = sourceG.Slice(context.SourceReadOffset.Y * bytesPerScanlineG);
sourceB = sourceB.Slice(context.SourceReadOffset.Y * bytesPerScanlineB);
sourceA = sourceB.Slice(context.SourceReadOffset.Y * bytesPerScanlineA);
using TiffPixelBufferWriter <TiffRgba64> writer = context.GetWriter <TiffRgba64>();
int rows = context.ReadSize.Height;
int cols = context.ReadSize.Width;
// BitReader.Read reads bytes in big-endian way, we only need to reverse the endianness if the source is little-endian.
bool isLittleEndian = context.IsLittleEndian;
bool reverseEndiannessR = isLittleEndian && bitsPerSample[0] % 8 == 0;
bool reverseEndiannessG = isLittleEndian && bitsPerSample[1] % 8 == 0;
bool reverseEndiannessB = isLittleEndian && bitsPerSample[2] % 8 == 0;
bool reverseEndiannessA = isLittleEndian && bitsPerSample[3] % 8 == 0;
bool canDoFastPath = bitsPerSample[0] >= 16 && bitsPerSample[1] >= 16 && bitsPerSample[2] >= 16 && bitsPerSample[3] >= 16 &&
!reverseEndiannessR & !reverseEndiannessG & !reverseEndiannessB & !reverseEndiannessA;
TiffRgba64 pixel = default;
for (int row = 0; row < rows; row++)
{
using TiffPixelSpanHandle <TiffRgba64> pixelSpanHandle = writer.GetRowSpan(row);
Span <TiffRgba64> pixelSpan = pixelSpanHandle.GetSpan();
var bitReaderR = new BitReader(sourceR.Slice(0, bytesPerScanlineR), isHigherOrderBitsFirst);
var bitReaderG = new BitReader(sourceG.Slice(0, bytesPerScanlineG), isHigherOrderBitsFirst);
var bitReaderB = new BitReader(sourceB.Slice(0, bytesPerScanlineB), isHigherOrderBitsFirst);
var bitReaderA = new BitReader(sourceA.Slice(0, bytesPerScanlineA), isHigherOrderBitsFirst);
bitReaderR.Advance(context.SourceReadOffset.X * bitsPerSample[0]);
bitReaderG.Advance(context.SourceReadOffset.X * bitsPerSample[1]);
bitReaderB.Advance(context.SourceReadOffset.X * bitsPerSample[2]);
bitReaderA.Advance(context.SourceReadOffset.X * bitsPerSample[3]);
if (canDoFastPath)
{
// Fast path for bits >= 8
for (int col = 0; col < cols; col++)
{
pixel.R = (ushort)(FastExpandBits(bitReaderR.Read(bitsPerSample[0]), bitsPerSample[0], 32) >> 16);
pixel.G = (ushort)(FastExpandBits(bitReaderG.Read(bitsPerSample[1]), bitsPerSample[1], 32) >> 16);
pixel.B = (ushort)(FastExpandBits(bitReaderB.Read(bitsPerSample[2]), bitsPerSample[2], 32) >> 16);
pixel.A = (ushort)(FastExpandBits(bitReaderA.Read(bitsPerSample[3]), bitsPerSample[3], 32) >> 16);
pixelSpan[col] = pixel;
}
}
else
{
// Slow path
for (int col = 0; col < cols; col++)
{
pixel.R = (ushort)(ExpandBits(bitReaderR.Read(bitsPerSample[0]), bitsPerSample[0], 32, reverseEndiannessR) >> 16);
pixel.G = (ushort)(ExpandBits(bitReaderG.Read(bitsPerSample[1]), bitsPerSample[1], 32, reverseEndiannessG) >> 16);
pixel.B = (ushort)(ExpandBits(bitReaderB.Read(bitsPerSample[2]), bitsPerSample[2], 32, reverseEndiannessB) >> 16);
pixel.A = (ushort)(ExpandBits(bitReaderA.Read(bitsPerSample[3]), bitsPerSample[3], 32, reverseEndiannessA) >> 16);
pixelSpan[col] = pixel;
}
}
if (_isAlphaAssociated)
{
if (_undoColorPreMultiplying)
{
UndoColorPreMultiplying(pixelSpan);
}
else
{
WipeAlphaChanel(pixelSpan);
}
}
sourceR = sourceR.Slice(bytesPerScanlineR);
sourceG = sourceG.Slice(bytesPerScanlineG);
sourceB = sourceB.Slice(bytesPerScanlineB);
sourceA = sourceA.Slice(bytesPerScanlineA);
}
return(next.RunAsync(context));
}
