/// <summary>
/// Render the whole file and write it back.
/// </summary>
private void WriteFile()
{
// Check, if IFD0 is contained
IFDTag exif = ImageTag.Exif;
if (exif == null)
throw new Exception ("Tiff file without tags");
UpdateTags (exif);
// first IFD starts at 8
uint first_ifd_offset = 8;
ByteVector data = RenderHeader (first_ifd_offset);
var renderer = new IFDRenderer (IsBigEndian, exif.Structure, first_ifd_offset);
data.Add (renderer.Render ());
Insert (data, 0, Length);
}
/// <summary>
/// Render the whole file and write it back.
/// </summary>
private void WriteFile ()
{
// Check, if IFD0 is contained
IFDTag exif = ImageTag.Exif;
if (exif == null)
throw new Exception ("Tiff file without tags");
UpdateTags (exif);
// first IFD starts at 8
uint first_ifd_offset = 8;
ByteVector data = new ByteVector ();
if (is_bigendian)
data.Add ("MM");
else
data.Add ("II");
data.Add (ByteVector.FromUShort (42, is_bigendian));
data.Add (ByteVector.FromUInt (first_ifd_offset, is_bigendian));
var renderer = new IFDRenderer (is_bigendian, exif.Structure, first_ifd_offset);
data.Add (renderer.Render ());
Insert (data, 0, Length);
}
/// <summary>
/// Creates a <see cref="ByteVector"/> for the Exif segment of this file
/// </summary>
/// <returns>
/// A <see cref="ByteVector"/> with the whole Exif segment, if exif tags
/// exists, otherwise null.
/// </returns>
private ByteVector RenderExifSegment ()
{
// Check, if IFD0 is contained
IFDTag exif = ImageTag.Exif;
if (exif == null)
return null;
// first IFD starts at 8
uint first_ifd_offset = 8;
// Render IFD0
// FIXME: store endianess and use it here
var renderer = new IFDRenderer (true, exif.Structure, first_ifd_offset);
ByteVector exif_data = renderer.Render ();
uint segment_size = (uint) (first_ifd_offset + exif_data.Count + 2 + 6);
// do not render data segments, which cannot fit into the possible segment size
if (segment_size > ushort.MaxValue)
throw new Exception ("Exif Segment is too big to render");
// Create whole segment
ByteVector data = new ByteVector (new byte [] { 0xFF, (byte) Marker.APP1 });
data.Add (ByteVector.FromUShort ((ushort) segment_size));
data.Add ("Exif\0\0");
data.Add (ByteVector.FromString ("MM", StringType.Latin1));
data.Add (ByteVector.FromUShort (42));
data.Add (ByteVector.FromUInt (first_ifd_offset));
// Add ifd data itself
data.Add (exif_data);
return data;
}