[PATCH 1/3] windowscodecs: Add initial implementation of the GIF encoder.

[Dmitry Timoshkov]

"Esme Povirk (they/them)" <vincent at codeweavers.com> wrote:

> > > If possible, I would prefer not to maintain an implementation of LZW
> > > compression.
> >
> > Why? It's plain and simple. In comparison LZW decoder is more complicated,
> > but we have it included.
> 
> That was before my time, I just moved it from the old olepicture code.
> I don't know what the rationale was for importing gif decompression
> code.

There were some fixes in the imported GIF decoder code in windowscodecs:
support for missing GIF terminator, bugs in extensions handling. It would
take years to make fixes included in an external library, and then get
distributions to update their packages.

> Surprisingly, I can't find a library we could use for LZW compression,
> so maybe we do need to include it. We could add a dependency on a gif
> library, but that doesn't seem worth it to me.

There are different flavours of LZW, and GIF in particular has its own
adaptation (dictionary size, GIF blocks, GIF terminator). For instance
TIFF implementation of LZW compression is different.

-- 
Dmitry.