2005.02.02 17:50 "Re: [Tiff] converting tags", by Lee Howard
My understanding is that SGI reserved tags 34908 through 34914 for HylaFAX. We're currently only using 34908-34910. If my understanding is incorrect, please correct me.
The one who registered that set of tags knows what was they purpose in the first place. If you are sure that those tags are intended for Hylafax and still don't used for other purpose you can pick up the unused one.
I've communicated with Sam, and he confirmed with me that he registered those tags himself (for HylaFAX or whatever, but 34911-34914 went unused by him). They are registered in SGI's name, though, so he cannot say what SGI may or may not have done with the unused tags since he's no longer at SGI, but he "highly doubts" that there would be any conflict if HylaFAX were to start using 34911. So I'd like to proceed with that, then... unless I need to somehow get some authoritative confirmation from someone at SGI.
When you will have the special tag I can add support for it into libtiff.
Thanks. I'll need to write up a patch for suggested libtiff support for the new tag myself, to test it while I work on the HylaFAX side of things.
I'm having some trouble doing this. The tag will contain the raw DCS string (originating with 8-bit units) sent by the fax sender. As this DCS string may likely contain null characters, the tag must contain two fields: a length field and a data field. I would appreciate your assistence.
I've attached a patch of my latest attempt at getting this tag into libtiff. The patch is based on CVS-HEAD and includes some further changes to tif_jpeg.c that I think maybe you missed when you added the fax tags to it.