/// <summary>
/// Initializes a new instance of the <see cref="JPEGFile"/> class from the
/// specified data stream.
/// </summary>
/// <param name="stream">A <see cref="Sytem.IO.Stream"/> that contains image data.</param>
/// <param name="encoding">The encoding to be used for text metadata when the source encoding is unknown.</param>
protected internal TIFFFile(Stream stream, System.Text.Encoding encoding)
{
Format = ImageFileFormat.TIFF;
IFDs = new List <ImageFileDirectory>();
Encoding = encoding;
// Read the entire stream
byte[] data = Utility.GetStreamBytes(stream);
// Read the TIFF header
TIFFHeader = TIFFHeader.FromBytes(data, 0);
uint nextIFDOffset = TIFFHeader.IFDOffset;
if (nextIFDOffset == 0)
{
throw new NotValidTIFFileException("The first IFD offset is zero.");
}
// Read IFDs in order
while (nextIFDOffset != 0)
{
ImageFileDirectory ifd = ImageFileDirectory.FromBytes(data, nextIFDOffset, TIFFHeader.ByteOrder);
nextIFDOffset = ifd.NextIFDOffset;
IFDs.Add(ifd);
}
// Process IFDs
// TODO: Add support for multiple frames
foreach (ImageFileDirectoryEntry field in IFDs[0].Fields)
{
Properties.Add(ExifPropertyFactory.Get(field.Tag, field.Type, field.Count, field.Data, BitConverterEx.SystemByteOrder, IFD.Zeroth, Encoding));
}
}
/// <summary>
/// Returns a <see cref="TIFFHeader"/> initialized from the given byte data.
/// </summary>
/// <param name="data">The data.</param>
/// <param name="offset">The offset into <paramref name="data"/>.</param>
/// <returns>A <see cref="TIFFHeader"/> initialized from the given byte data.</returns>
public static TIFFHeader FromBytes(byte[] data, int offset)
{
TIFFHeader header = new TIFFHeader();
// TIFF header
if (data[offset] == 0x49 && data[offset + 1] == 0x49)
{
header.ByteOrder = BitConverterEx.ByteOrder.LittleEndian;
}
else if (data[offset] == 0x4D && data[offset + 1] == 0x4D)
{
header.ByteOrder = BitConverterEx.ByteOrder.BigEndian;
}
else
{
throw new NotValidTIFFHeader();
}
// TIFF header may have a different byte order
if (BitConverterEx.LittleEndian.ToUInt16(data, offset + 2) == 42)
{
header.TIFFHeaderByteOrder = BitConverterEx.ByteOrder.LittleEndian;
}
else if (BitConverterEx.BigEndian.ToUInt16(data, offset + 2) == 42)
{
header.TIFFHeaderByteOrder = BitConverterEx.ByteOrder.BigEndian;
}
else
{
throw new NotValidTIFFHeader();
}
header.ID = 42;
// IFD offset
header.IFDOffset = BitConverterEx.ToUInt32(data, offset + 4, header.TIFFHeaderByteOrder, BitConverterEx.SystemByteOrder);
return(header);
}