Re: [AD] GIF patent / support

[Daniel Schlyder <daniel@xxxxxxxxxx>]

Chris La Mantia:
> From: "Elias Pschernig" <allefant@xxxxxxxxxx>
>> Nah, that has nothing to do with it for sure - else why do we support
>> BMP and not XPM? And PNG doesn't even support animation, so it will
>> never replace GIF on websites. Only not-animated pictures just make
>> not much sense for a website (so you have to use GIF, and why then
>> also use PNG), and for photos you have JPG.

> I was under the impression that there was animation support in the
> specification, but it is not widely implemented.

You're supposed to use the related MNG format for animations.

>> I agree, LBM (and also PCX) support should be in addons. And as was
>> said the last time we talked about this on this list I think - GIF
>> animations would be hard to support with the current load_bitmap API

> At the time, PCX was a common image format.  I'm not sure LBM was ever
> common.  Although it's true that in this day and age LBM (if not all image
> formats) would be add-ons, it is counter-productive to remove working
> formats from Allegro.  However, it still seems reasonable to internally
> support at least one common format.  I'm sure if it was easy to do so and
> did not introduce any licensing changes or library dependencies, PNG would
> be internally supported.  As it stands, though, that is not possible (to the
> best of my knowledge).  I still believe that the underlying argument against
> GIF is the predjudice against it as a result of Unisys's actions and that
> the "external add-on" is just a convenient way to brush it aside.

I'm not opposed to adding GIF support (not that my opinion matters), but is
GIF really a common format outside of web development? And aren't most games
using truecolour graphics these days and have done so for years?

BTW, there might still be patent issues. Here's a quote from a recent post
to the Boost mailing list:

<quote>
 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...

http://sourceforge.net/projects/libungif
SourceForge.net: Project Info - Libungif - An uncompressed GIF library
</quote>

--
Daniel Schlyder
http://bitblaze.com/