2020.02.11 17:43 "Re: [Tiff] recommended way to support a different compression", by Bob Friesenhahn

Thanks for responding! Yes, as I understand, for the 1st method I would need to add an entry to the _TIFFBuiltinCODECS array and follow the rest of the steps outlined in the link<http://www.simplesystems.org/libtiff/internals.html#AddingCODECS> to properly add the new codec to libtiff, and for the 2nd method I would need to use the TIFFRegisterCODEC function. Is there anything else you mean by registering?

I am interested in being able to read TIFF files with some IFDs having a custom compression that is not currently supported by libtiff. Is it an uncommon problem? I am able to do decoding on the data I get from TIFFReadRawTile, but adding a codec seems like a better solution.

Adobe used to support a process by which Adobe would assign new unique integer identifiers for TIFF tags and compression attributes. Perhaps this is what Leonard Rosenthol is referring to.

If you are only reading TIFF files, then there is no need to worry about such formalities.

Recently support for Zstd and WebP compression was added to libtiff so these additions should serve as useful examples.

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