/// <summary>Reads JPEG SOF values and returns them in a <see cref="JpegDirectory"/>.</summary>
public JpegDirectory Extract(JpegSegment segment)
{
var directory = new JpegDirectory();
// The value of TagCompressionType is determined by the segment type found
directory.Set(JpegDirectory.TagCompressionType, (int)segment.Type - (int)JpegSegmentType.Sof0);
SequentialReader reader = new SequentialByteArrayReader(segment.Bytes);
try
{
directory.Set(JpegDirectory.TagDataPrecision, reader.GetByte());
directory.Set(JpegDirectory.TagImageHeight, reader.GetUInt16());
directory.Set(JpegDirectory.TagImageWidth, reader.GetUInt16());
var componentCount = reader.GetByte();
directory.Set(JpegDirectory.TagNumberOfComponents, componentCount);
// For each component, there are three bytes of data:
// 1 - Component ID: 1 = Y, 2 = Cb, 3 = Cr, 4 = I, 5 = Q
// 2 - Sampling factors: bit 0-3 vertical, 4-7 horizontal
// 3 - Quantization table number
for (var i = 0; i < componentCount; i++)
{
var componentId = reader.GetByte();
var samplingFactorByte = reader.GetByte();
var quantizationTableNumber = reader.GetByte();
var component = new JpegComponent(componentId, samplingFactorByte, quantizationTableNumber);
directory.Set(JpegDirectory.TagComponentData1 + i, component);
}
}
catch (IOException ex)
{
directory.AddError(ex.Message);
}
return(directory);
}
/// <summary>Reads JPEG SOF values and returns them in a <see cref="JpegDirectory"/>.</summary>
public JpegDirectory Extract(byte[] segmentBytes, JpegSegmentType segmentType)
{
var directory = new JpegDirectory();
// The value of TagCompressionType is determined by the segment type found
directory.Set(JpegDirectory.TagCompressionType, (int)segmentType - (int)JpegSegmentType.Sof0);
SequentialReader reader = new SequentialByteArrayReader(segmentBytes);
try
{
directory.Set(JpegDirectory.TagDataPrecision, reader.GetByte());
directory.Set(JpegDirectory.TagImageHeight, reader.GetUInt16());
directory.Set(JpegDirectory.TagImageWidth, reader.GetUInt16());
var componentCount = reader.GetByte();
directory.Set(JpegDirectory.TagNumberOfComponents, componentCount);
// for each component, there are three bytes of data:
// 1 - Component ID: 1 = Y, 2 = Cb, 3 = Cr, 4 = I, 5 = Q
// 2 - Sampling factors: bit 0-3 vertical, 4-7 horizontal
// 3 - Quantization table number
for (var i = 0; i < (int)componentCount; i++)
{
int componentId = reader.GetByte();
int samplingFactorByte = reader.GetByte();
int quantizationTableNumber = reader.GetByte();
var component = new JpegComponent(componentId, samplingFactorByte, quantizationTableNumber);
directory.Set(JpegDirectory.TagComponentData1 + i, component);
}
}
catch (IOException ex)
{
directory.AddError(ex.Message);
}
return directory;
}
public JpegDescriptorTest()
{
_directory = new JpegDirectory();
_descriptor = new JpegDescriptor(_directory);
}
public JpegDirectoryTest()
{
_directory = new JpegDirectory();
}
public JpegReaderTest()
{
_directory = ProcessBytes("Tests/Data/simple.jpg.sof0");
}