2005.12.12 22:49 "Re: [Tiff] Writing EXIF data?", by Bob Friesenhahn

Recently, support was added in libtiff (in 3.7.3) to support tags in EXIF IFDs. Presumably it it is possible to create an EXIF IFD from scratch, or update an existing EXIF IFD, if you know what you are doing. Previous versions which supported TIFFTAG_EXIFIFD are very limited (as you describe), and older versions don't know anything about EXIF at all. So everything depends on what version of libtiff you are using.

Bob

How can one write EXIF metadata to a TIFF image? There's the (undocumented) TIFFTAG_EXIFIFD tag that can be used with TIFFSetField(), but its value is (apparently) the pointer to the EXIF data and not the data itself. The library, given the data, needs to put it in the right place. Right?

So how does one set EXIF metadata?

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