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From: Rene Rivera (grafik.list_at_[hidden])
Date: 2004-10-03 13:46:04

Jonathan Turkanis wrote:

> "Rene Rivera" <grafik.list_at_[hidden]> wrote in message
>>The LZW patent in question expired in the US this Summer. But the patent
>>only applies to generation of GIFs, not reading. So it's only the one
>>person who created the GIF that would have needed a license. There are
>>still other countries out there that have the patent active though.
> Thanks for clarifying this. I was hoping the expiration of the LZW patent meant
> I could add LZW compression to the iostreams library. To you have more info on
> which other countries have issued patents on this algorithm which have yet to
> expire?

 From the UniSys mouth...

Unisys U.S. LZW Patent No. 4,558,302 expired on June 20, 2003, the
counterpart patents in the United Kingdom, France, Germany and Italy
expired on June 18, 2004, the Japanese counterpart patents expired on
June 20, 2004 and the counterpart Canadian patent expired on July 7, 2004.

But according to the libungif developers, and the FSF...

giflib is able to read and write all GIF files using the LZW algorithm
patented by UniSys. Although this patent has expired in the United
States, patent searches by the FSF show that worldwide patents exist
until 2006. If you must have a patent free version of the library,
please look into libungif as a suitable replacement.

So perhaps you could ask them... Project Info - Libungif - An uncompressed GIF library

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