On Mon, 2005-09-19 at 10:50 -1000, Warren Togami wrote:
Michael A. Peters wrote:
> Can we replace libungif with giflib in fc5?
>
> The LZW patent is dead, Unisys specifically says so on their website.
>
> The current version of gd shipping with Fedora now supports gif.
> The cvs version of gnuplot now supports the gif terminal type again
> using the gd library.
> The libtiff library in fc4 now has lzw patched back in.
>
> I've been using giflib on my system since fc3 (removing libungif and
> installing giflib in its place, with the shared library symlinks going
> the other way) and there are absolutely no issues.
>
> I'll file a bugzilla on libungif for it, I think I might have already in
> the past - but are there any other reasons anyone can think of for not
> going with giflib?
>
> giflib is available from same sourceforge location as libungif and being
> maintained in parallel with libungif. I'm guessing it is only a matter
> of time before libungif disappears.
>
http://sourceforge.net/projects/libungif
"A library for reading and writing gif images. The save functionality
uses an uncompressed gif algorithm to avoid the Unisys LZW patent. This
library is based on Eric Raymond's giflib and implements a superset of
that library's API. "
This and other hits on Google indicate that libungif has some exported
functions that giflib lacks. Are you sure this is a perfectly safe
drop-in replacement? There are not a whole lot of details on this website.
The history of libungif and giflib is that GNOME 1 (via imlib) began to
use giflib for its GIF support. Red Hat and other distributions
realized this would cause problems due to the Unisys LZW patent. I
found a posting that showed how to create uncompressed gifs that
wouldn't invoke the patent (Unisys patented the encoder and combined
decoder+encoder... Not a standalone decoder) and created libungif as a
drop in replacement for giflib to circumvent the patent issues.
As time went on, bugfixes and a desire for new features led to a need
for API/ABI changes. I sent fixes and enhancements to Eric Raymond to
coordinate a release so we could continue to have compatible libraries.
He wasn't interested in maintaining giflib any more so I took over
maintenence of that. The sourceforge page reflects that libungif is a
superset of esr's giflib but not the present sourceforge hosted giflib.
I'll go carify the web page now.
-Toshio