TIFF and LibTiff Mail List Archive


1999.11.30 22:23 "libtiff 3.5.3 release.", by Michael L. Welles
1999.12.01 03:15 "Re: libtiff 3.5.3 release.", by Bob Friesenhahn
1999.12.01 16:04 "Re: libtiff 3.5.3 release.", by Michael L. Welles
1999.12.01 16:43 "Re: libtiff 3.5.3 release.", by Tom Lane

1999.12.01 16:04 "Re: libtiff 3.5.3 release.", by Michael L. Welles

Not offhand, but their new position seems pretty clear:

> Unisys has frequently been asked whether a Unisys license is required > in order to use LZW software obtained by downloading from the Internet

> or from other sources. The answer is simple. In all cases, a written > license agreement or statement signed by an authorized Unisys

> representative is required from Unisys for all use, sale or > distribution of any software (including so-called "freeware") and/or

> hardware providing LZW conversion capability (for example, downloaded > software used for creating/displaying GIF images).


I'd rather not be in violation by default. I'd prefer to make a patch or a branch distribution available for users who are licensed or are willing to take the risk. It's a pretty small change, and it'd be relatively easy to maintain.

On a seperate note, gd (, before switching to PNG, was shipping (as of 1.3) with LZW decompressor compatable run length encoding. I've grabbed the source and will be looking into adding this code as the default compressor. gd has a BSD-ish license, so the GPL "viral" effect shouldn't apply, though it's a little unclear:

> Permission has been granted to copy and distribute gd in any context > without fee, including a commercial application, provided that this

> notice is present in user-accessible supporting documentation.

If the RLE code looks good, I might contact the authors (Hutchison Avenue Software Corporation) for their permission to distribute under the standard libtiff license.

M. L.  Welles