/// <summary>
/// Read field descriptor from block.
/// A "property" of the image.
/// </summary>
/// <param name="IDBlock">Block containing descriptor, but NOT it's data.</param>
/// <param name="endianness">Big or little endianness defined by TIFF header.</param>
/// <param name="dataStream">Full image stream to read descriptor data from.</param>
public FieldDescriptor(byte[] IDBlock, MyBitConverter.Endianness endianness, Stream dataStream)
{
FieldTag = (FieldTags)MyBitConverter.ToInt16(IDBlock, 0, endianness);
FieldType = (FieldTypes)MyBitConverter.ToInt16(IDBlock, 2, endianness);
FieldLength = MyBitConverter.ToInt32(IDBlock, 4, endianness);
DataOffset = MyBitConverter.ToInt32(IDBlock, 8, endianness);
// Read data indicated by descriptor
long oldOffset = dataStream.Position;
dataStream.Seek(DataOffset, SeekOrigin.Begin);
Data = new byte[FieldLength];
dataStream.Read(Data, 0, FieldLength);
// Reset stream position for next descriptor
dataStream.Seek(oldOffset, SeekOrigin.Begin);
}
/// <summary>
/// Read sub image header.
/// </summary>
/// <param name="stream">Stream to read local header from.</param>
/// <param name="endianness">Big or little, as defined by TIFF header.</param>
public ImageFileDirectory(Stream stream, MyBitConverter.Endianness endianness)
: this()
{
var bytes = stream.ReadBytes(2);
NumberOfEntries = MyBitConverter.ToUInt16(bytes, 0, endianness);
FieldDescriptors = new List<FieldDescriptor>();
for (int i = 0; i < NumberOfEntries; i++)
{
bytes = stream.ReadBytes(12);
FieldDescriptors.Add(new FieldDescriptor(bytes, endianness, stream));
}
}
