Re: [XaraXtreme-dev] Just checked in...

[Alex Bligh <alex@xxxxxxxxxxx>]

--On 13 April 2006 12:36 +0100 Phil Martin <phil@xxxxxxxx> wrote:


> I've just checked in changes to allow the conditional code enabled by
> DO_EXPORT to compile.

That's great news.

> * The GIF filter is in but does nothing because we don't yet have a GIF
> reading/writing library in the code. Did the GIF patent lapse recently?
> Can we use giflib now?

The GIF patent problem is down to the Unisys LZW patent which has expired
in the EU AFAIUI, and I think in the US too; but I'm not /sure/ it's
expired everywhere. But you can use
http://sourceforge.net/projects/libungif
which is ABI compatible with giflib in any case, allowing the user
to locally chose whether or not he wants to support LZW GIFs at
load time through dynamic linking. Dynamic linking effectively pushes
the patent problem onto someone else. Libungif is MIT licensed (i.e.
BSD in all but name).

There seems to be piles of code which is dependent on the GIF stuff for 
reasons I don't entirely understand, and untangling that was the biggest 
PITA in getting galleries working. Like a lot of galleries code, especially 
sgframe etc. - I presume this is for generating preview bitmaps etc., and 
(as far as sgframe is concerned) looking into the various frames of a 
multi-image gif. It seems to me that none of these should be specifically 
tied to GIF format.

Alex