2005.12.13 15:07 "Re: [Tiff] Writing EXIF data?", by Joris Van Damme
I assume that is the reason why you feel the EXIF tag is
> > undocumented. It's documented allright
It's in the header file, but not on the TIFFSetField manual page. Hence, it's undocumented.
OK, then TIFFSetField on the EXIF tag is undocumented. I understood your comment in another way. Mea culpa.
Not properly implementing tag namespaces, LibTiff has troubles with this concept. How is it supposed to define GPSLatitudeRef, or, the other way around, how is it supposed to make sense of tag ID code 1, when it has no clue 'bout namespaces?
For EXIF at least, libtiff doesn't need to know anything about EXIF tags except the EXIF IFD pointer (which already has a #define for it in the header file). I merely want to insert a blob of binary data into the TIFF file that's being created and have the EXIF IFD pointer point to it. The libtiff library doesn't have to know or care about the contents of the blob.
You do realize the 'blob' is an IFD, as I tried to explain? Most people want to use LibTiff to read and write the tags in that IFD, too. But if you've done all that in another way, already, things may be easier, and someone here may be able to point you in the right direction if a right direction exists.
May I ask how you wrote that IFD that you refer to as 'blob'?
Sorry I can't be more helpful. My departement is mainly the file format, not the library. I sense a little aggrevation, and I can understand that, but apart from understanding there's little I can do. I recommend you explain how you wrote the 'blob' and convince the right persons that all you want is to set the EXIF tag value to a particular known offset. If you've any funds for solving any problems that you may experience, I recommend mentioning that too.
Joris Van Damme
Download your free TIFF tag viewer for windows here: