/// <inheritdoc />
public void Compress(TiffCompressionContext context, ReadOnlyMemory <byte> input, IBufferWriter <byte> outputWriter)
{
if (context is null)
{
throw new ArgumentNullException(nameof(context));
}
if (outputWriter is null)
{
throw new ArgumentNullException(nameof(outputWriter));
}
if (_encoder is null)
{
throw new InvalidOperationException("JPEG encoder is not initialized.");
}
if (context.PhotometricInterpretation != _photometricInterpretation)
{
throw new InvalidOperationException();
}
CheckBitsPerSample(context.BitsPerSample);
TiffJpegEncoder encoder = _encoder.CloneParameter();
encoder.MemoryPool = context.MemoryPool;
// Input
JpegBufferInputReader inputReader = Interlocked.Exchange(ref _inputReader, null) ?? new JpegBufferInputReader();
encoder.SetInputReader(inputReader);
// Update InputReader
inputReader.Update(context.ImageSize.Width, context.ImageSize.Height, _componentCount, input);
// Output
encoder.SetOutput(outputWriter);
// Encoder
encoder.Encode(!_useSharedHuffmanTables, !_useSharedQuantizationTables, _optimizeCoding);
// Reset state
inputReader.Reset();
// Cache the input reader instance
Interlocked.CompareExchange(ref _inputReader, inputReader, null);
}
private void Initialize(int quality, bool optimizeCoding)
{
TiffJpegEncoder encoder;
switch (_photometricInterpretation)
{
case TiffPhotometricInterpretation.BlackIsZero:
case TiffPhotometricInterpretation.WhiteIsZero:
_componentCount = 1;
encoder = new TiffJpegEncoder(minimumBufferSegmentSize: MinimumBufferSegmentSize);
encoder.SetQuantizationTable(JpegStandardQuantizationTable.ScaleByQuality(JpegStandardQuantizationTable.GetLuminanceTable(JpegElementPrecision.Precision8Bit, 0), quality));
if (optimizeCoding)
{
encoder.SetHuffmanTable(true, 0);
encoder.SetHuffmanTable(false, 0);
}
else
{
encoder.SetHuffmanTable(true, 0, JpegStandardHuffmanEncodingTable.GetLuminanceDCTable());
encoder.SetHuffmanTable(false, 0, JpegStandardHuffmanEncodingTable.GetLuminanceACTable());
}
encoder.AddComponent(0, 0, 0, 0, 1, 1); // Y component
break;
case TiffPhotometricInterpretation.RGB:
_componentCount = 3;
encoder = new TiffJpegEncoder(minimumBufferSegmentSize: MinimumBufferSegmentSize);
encoder.SetQuantizationTable(JpegStandardQuantizationTable.ScaleByQuality(JpegStandardQuantizationTable.GetLuminanceTable(JpegElementPrecision.Precision8Bit, 0), quality));
if (optimizeCoding)
{
encoder.SetHuffmanTable(true, 0);
encoder.SetHuffmanTable(false, 0);
}
else
{
encoder.SetHuffmanTable(true, 0, JpegStandardHuffmanEncodingTable.GetLuminanceDCTable());
encoder.SetHuffmanTable(false, 0, JpegStandardHuffmanEncodingTable.GetLuminanceACTable());
}
encoder.AddComponent(0, 0, 0, 0, 1, 1); // R component
encoder.AddComponent(1, 0, 0, 0, 1, 1); // G component
encoder.AddComponent(2, 0, 0, 0, 1, 1); // B component
break;
case TiffPhotometricInterpretation.Seperated:
_componentCount = 4;
encoder = new TiffJpegEncoder(minimumBufferSegmentSize: MinimumBufferSegmentSize);
encoder.SetQuantizationTable(JpegStandardQuantizationTable.ScaleByQuality(JpegStandardQuantizationTable.GetLuminanceTable(JpegElementPrecision.Precision8Bit, 0), quality));
if (optimizeCoding)
{
encoder.SetHuffmanTable(true, 0);
encoder.SetHuffmanTable(false, 0);
}
else
{
encoder.SetHuffmanTable(true, 0, JpegStandardHuffmanEncodingTable.GetLuminanceDCTable());
encoder.SetHuffmanTable(false, 0, JpegStandardHuffmanEncodingTable.GetLuminanceACTable());
}
encoder.AddComponent(0, 0, 0, 0, 1, 1); // C component
encoder.AddComponent(1, 0, 0, 0, 1, 1); // M component
encoder.AddComponent(2, 0, 0, 0, 1, 1); // Y component
encoder.AddComponent(3, 0, 0, 0, 1, 1); // K component
break;
case TiffPhotometricInterpretation.YCbCr:
_componentCount = 3;
encoder = new TiffJpegEncoder(minimumBufferSegmentSize: MinimumBufferSegmentSize);
encoder.SetQuantizationTable(JpegStandardQuantizationTable.ScaleByQuality(JpegStandardQuantizationTable.GetLuminanceTable(JpegElementPrecision.Precision8Bit, 0), quality));
encoder.SetQuantizationTable(JpegStandardQuantizationTable.ScaleByQuality(JpegStandardQuantizationTable.GetChrominanceTable(JpegElementPrecision.Precision8Bit, 1), quality));
if (optimizeCoding)
{
encoder.SetHuffmanTable(true, 0);
encoder.SetHuffmanTable(false, 0);
encoder.SetHuffmanTable(true, 1);
encoder.SetHuffmanTable(false, 1);
}
else
{
encoder.SetHuffmanTable(true, 0, JpegStandardHuffmanEncodingTable.GetLuminanceDCTable());
encoder.SetHuffmanTable(false, 0, JpegStandardHuffmanEncodingTable.GetLuminanceACTable());
encoder.SetHuffmanTable(true, 1, JpegStandardHuffmanEncodingTable.GetChrominanceDCTable());
encoder.SetHuffmanTable(false, 1, JpegStandardHuffmanEncodingTable.GetChrominanceACTable());
}
encoder.AddComponent(0, 0, 0, 0, (byte)_horizontalSubsampling, (byte)_verticalSubsampling); // Y component
encoder.AddComponent(1, 1, 1, 1, 1, 1); // Cb component
encoder.AddComponent(2, 1, 1, 1, 1, 1); // Cr component
break;
default:
throw new NotSupportedException("JPEG compression only supports BlackIsZero, WhiteIsZero, RGB, YCbCr and CMYK photometric interpretation.");
}
_encoder = encoder;
}
public JpegTableWriter(TiffJpegEncoder encoder, bool useSharedHuffmanTables, bool useSharedQuantizationTables)
{
_encoder = encoder;
_useSharedHuffmanTables = useSharedHuffmanTables;
_useSharedQuantizationTables = useSharedQuantizationTables;
}
