2016.01.11 14:18 "Re: [Tiff] Problem with TIFFCurrentDirectory", by Olivier Paquet

2016-01-11 6:19 GMT-05:00 John Stevenson-Hoare <John.Stevenson-Hoare@ffei.co.uk>:

The man pages state that directories are indexed from 0, but when I create a new TIFF and invoke TIFFCurrentDirectory the return value is 65535. Is this a bug?

I would say yes but it has been around for so long that there might be applications depending on it. The counter is set to -1 initially and incremented when a directory is read. But it is incremented only after directories are written so it's always late by 1 when writing a new file. As far as I could see, the code dates back to the origin of the CVS repo (1999). It might have been done that way on purpose... but I can't see why and it's certainly confusing.

Directories are indeed counted from 0 so your best way out is probably to just count them yourself when writing for now.

My problem is that I need to cache the indexes of directories as I create them so that I can re-visit and update them. If I do this with a file containing 2 directories (both tiled images) the library reports:

That's an entirely different problem. libtiff wasn't really designed for that kind of use but it might be possible to do what you want, with some constraints. See the mailing list archive for February 2015.

Olivier Paquet