[OSGeo-Discuss] any library for modifying TIFF tags ?

[Jachym Cepicky]

Hi,

I try o add custom (proprietary) tags to TIFF files. I tried to modify
libtiff [1] according to [2], I added lines

libtiff/tiff.h:
    #define TIFFTAG_SIGNATURE    65001

libtiff/tif_dirinfo.c (line 392):
        { TIFFTAG_SIGNATURE,    TIFF_VARIABLE, TIFF_VARIABLE,
        TIFF_UNDEFINED, FIELD_CUSTOM, 1,    0,  "Signature" },

The tag should be TIFF_UNDEFINED according to documentation. I'm able to
read the tag value, but never able to set the tag value, no matter, if
the tag is already available in the image or not (fresh image).

I wanted to ask, if there is someone out there, who successfully uses
libtiff or similar/other library/program, for editing of tiff
(preferably UNDEFINED) tags. Any experience with Python-Image?

Thanks

Jachym

[1] http://www.remotesensing.org/libtiff/
[2] http://www.remotesensing.org/libtiff/addingtags.html
-- 
Jachym Cepicky
e-mail: jachym.cepicky gmail com
URL: http://les-ejk.cz
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