/// <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="ImageFileDirectory"/> initialized from the given byte data.
/// </summary>
/// <param name="data">The data.</param>
/// <param name="offset">The offset into <paramref name="data"/>.</param>
/// <param name="byteOrder">The byte order of <paramref name="data"/>.</param>
/// <returns>A <see cref="ImageFileDirectory"/> initialized from the given byte data.</returns>
public static ImageFileDirectory FromBytes(byte[] data, uint offset, BitConverterEx.ByteOrder byteOrder)
{
ImageFileDirectory ifd = new ImageFileDirectory();
BitConverterEx conv = new BitConverterEx(byteOrder, BitConverterEx.SystemByteOrder);
List <uint> stripOffsets = new List <uint>();
List <uint> stripLengths = new List <uint>();
// Count
ushort fieldcount = conv.ToUInt16(data, offset);
// Read fields
for (uint i = 0; i < fieldcount; i++)
{
uint fieldoffset = offset + 2 + 12 * i;
ImageFileDirectoryEntry field = ImageFileDirectoryEntry.FromBytes(data, fieldoffset, byteOrder);
ifd.Fields.Add(field);
// Read strip offsets
if (field.Tag == 273)
{
int baselen = field.Data.Length / (int)field.Count;
for (uint j = 0; j < field.Count; j++)
{
byte[] val = new byte[baselen];
Array.Copy(field.Data, j * baselen, val, 0, baselen);
uint stripOffset = (field.Type == 3 ? (uint)BitConverter.ToUInt16(val, 0) : BitConverter.ToUInt32(val, 0));
stripOffsets.Add(stripOffset);
}
}
// Read strip lengths
if (field.Tag == 279)
{
int baselen = field.Data.Length / (int)field.Count;
for (uint j = 0; j < field.Count; j++)
{
byte[] val = new byte[baselen];
Array.Copy(field.Data, j * baselen, val, 0, baselen);
uint stripLength = (field.Type == 3 ? (uint)BitConverter.ToUInt16(val, 0) : BitConverter.ToUInt32(val, 0));
stripLengths.Add(stripLength);
}
}
}
// Save strips
if (stripOffsets.Count != stripLengths.Count)
{
throw new NotValidTIFFileException();
}
for (int i = 0; i < stripOffsets.Count; i++)
{
ifd.Strips.Add(new TIFFStrip(data, stripOffsets[i], stripLengths[i]));
}
// Offset to next ifd
ifd.NextIFDOffset = conv.ToUInt32(data, offset + 2 + 12 * fieldcount);
return(ifd);
}
/// <summary>
/// Saves the <see cref="ImageFile"/> to the given stream.
/// </summary>
/// <param name="stream">The data stream used to save the image.</param>
public override void Save(Stream stream)
{
BitConverterEx conv = BitConverterEx.SystemEndian;
// Write TIFF header
uint ifdoffset = 8;
// Byte order
stream.Write((BitConverterEx.SystemByteOrder == BitConverterEx.ByteOrder.LittleEndian ? new byte[] { 0x49, 0x49 } : new byte[] { 0x4D, 0x4D }), 0, 2);
// TIFF ID
stream.Write(conv.GetBytes((ushort)42), 0, 2);
// Offset to 0th IFD, will be corrected below
stream.Write(conv.GetBytes(ifdoffset), 0, 4);
// Write IFD sections
for (int i = 0; i < IFDs.Count; i++)
{
ImageFileDirectory ifd = IFDs[i];
// Save the location of IFD offset
long ifdLocation = stream.Position - 4;
// Write strips first
byte[] stripOffsets = new byte[4 * ifd.Strips.Count];
byte[] stripLengths = new byte[4 * ifd.Strips.Count];
uint stripOffset = ifdoffset;
for (int j = 0; j < ifd.Strips.Count; j++)
{
byte[] stripData = ifd.Strips[j].Data;
byte[] oBytes = BitConverter.GetBytes(stripOffset);
byte[] lBytes = BitConverter.GetBytes((uint)stripData.Length);
Array.Copy(oBytes, 0, stripOffsets, 4 * j, 4);
Array.Copy(lBytes, 0, stripLengths, 4 * j, 4);
stream.Write(stripData, 0, stripData.Length);
stripOffset += (uint)stripData.Length;
}
// Remove old strip tags
for (int j = ifd.Fields.Count - 1; j > 0; j--)
{
ushort tag = ifd.Fields[j].Tag;
if (tag == 273 || tag == 279)
{
ifd.Fields.RemoveAt(j);
}
}
// Write new strip tags
ifd.Fields.Add(new ImageFileDirectoryEntry(273, 4, (uint)ifd.Strips.Count, stripOffsets));
ifd.Fields.Add(new ImageFileDirectoryEntry(279, 4, (uint)ifd.Strips.Count, stripLengths));
// Write fields after strips
ifdoffset = stripOffset;
// Correct IFD offset
long currentLocation = stream.Position;
stream.Seek(ifdLocation, SeekOrigin.Begin);
stream.Write(conv.GetBytes(ifdoffset), 0, 4);
stream.Seek(currentLocation, SeekOrigin.Begin);
// Offset to field data
uint dataOffset = ifdoffset + 2 + (uint)ifd.Fields.Count * 12 + 4;
// Field count
stream.Write(conv.GetBytes((ushort)ifd.Fields.Count), 0, 2);
// Fields
foreach (ImageFileDirectoryEntry field in ifd.Fields)
{
// Tag
stream.Write(conv.GetBytes(field.Tag), 0, 2);
// Type
stream.Write(conv.GetBytes(field.Type), 0, 2);
// Count
stream.Write(conv.GetBytes(field.Count), 0, 4);
// Field data
byte[] data = field.Data;
if (data.Length <= 4)
{
stream.Write(data, 0, data.Length);
for (int j = data.Length; j < 4; j++)
{
stream.WriteByte(0);
}
}
else
{
stream.Write(conv.GetBytes(dataOffset), 0, 4);
long currentOffset = stream.Position;
stream.Seek(dataOffset, SeekOrigin.Begin);
stream.Write(data, 0, data.Length);
dataOffset += (uint)data.Length;
stream.Seek(currentOffset, SeekOrigin.Begin);
}
}
// Offset to next IFD
ifdoffset = dataOffset;
stream.Write(conv.GetBytes(i == IFDs.Count - 1 ? 0 : ifdoffset), 0, 4);
}
}