2004.09.16 15:09 "Re: [Tiff] reading private subdirs", by Bob Friesenhahn

I see a couple approaches to this:

Introduce a version of the tiff_pdsdirread.c code into the core of libtiff specifically for reading non-image IFDs.

Try and make the normal directory reading somehow work with non-image IFDs.

I am inclined to think that (1) would be easier to incorporate without potentially causing alot of extra problems. However, I am unlikely to do the implementation myself so we will have to hear from Bob and Andrey. As Bob mentioned, he is hoping to develop and incorporate EXIF support into the libtiff core so it might be best to work with him to resolve this issue.

GraphicsMagick already includes code to parse an EXIF profile so even the existing libtiff trivial support for unrecognized tags should be sufficient for retrieving/parsing the profile. However, it would be nice to be able to write EXIF profiles as well. If libtiff includes support for the EXIF tag type then it should also know how to write the profile without any heavy-lifting.

Is it believed that libtiff should understand the innards of embedded profiles? It doesn't seem that this is libtiff's style.

Bob

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Bob Friesenhahn
bfriesen@simple.dallas.tx.us
http://www.simplesystems.org/users/bfriesen