2007.01.05 05:08 "FW: [Tiff] removing tiff tag in-place", by Gennady Khokhorin

Gerben,

I did a bit futher search, following did not work either:

const TIFFFieldInfo* fip = TIFFFindFieldInfo(in, TIFFTAG_DOCUMENTNAME, TIFF_ANY); TIFFClrFieldBit(in, fip->field_tag);

Output image' empty tags still there.

It could be other ways to make tags cleaning...

Gennady

-----Original Message-----

From: Gennady Khokhorin
Sent: Thursday, January 04, 2007 6:47 PM
To: 'Gerben Vos'
Subject: RE: [Tiff] removing tiff tag in-place

Hi, Gerben.

Can not make it work this way. No any FIELD tag for ascii data in the directory (tif_dir.h). All text data are marked as FIELD_CUSTOM (tif_dirinfo.c) probably because of variable length.

Was trying to invent those missing fields like that:

    { TIFFTAG_DOCUMENTNAME,             -1,-1,  TIFF_ASCII,     FIELD_DOCUMENTNAME,

      1,        0,      "DocumentName" },
where #define   FIELD_DOCUMENTNAME 50

And did break TIFFTAG<name> - FIELD<name> link, TIFFGetField() can not find documentName field anymore.

I'm going to put a request for this command in bug list.

Happy programming!
Gennady

I have an empty tags which want to remove from tif wout copying process. I tried TIFFSetField(tif, TIFFTAG_DOCUMENTNAME, ""); but tag still seats in the file. Is it possible to drop an empty ascii tags?

Try TIFFClrFieldBit(tif, FIELD_DOCUMENTNAME), a macro defined in tif_dir.h. Note: use FIELD_DOCUMENTNAME, not TIFFTAG_DOCUMENTNAME! I've never used it, but it looks like it does what you want. I don't think there currently is a public function for this, but I think it would be a good idea to have one.