[Scummvm-devel] png

[Willem Jan Palenstijn]

On Tue, Jul 24, 2012 at 11:10:41PM +0100, D G Turner wrote:
> Johannes,
>   Not to have an argument pointlessly... but I don't think that was the
>   conclusion of the discussion.
> 
>   Most of the thread indicated that (apart from the interlacing
>   support, which has now been added), our internal PNG decoder is
>   complete for our needs, so throwing it away and switching to an
>   external library seems like alot of work for little improvement.

There are still remaining issues with the de-interlacing code. I'd rather use
the well-tested libpng than debug and maintain our own version.

>   I don't think we should add further library dependencies, unless we
>   have very good reasons. Partly as they are generally not tested
>   over the variety of platforms we target.

I don't think that is true for libpng. Our current png decoder has had far less
testing...


>   Also, the code required to "shim" the library to the image decoder
>   API may result in worse overall performance, thus defeating the
>   object of the optimised library speed improvement.

Given how simple ImageDecoder is, that seems unlikely to have a serious impact.



But basically I see no advantage in maintaining our own PNG code. The only
potential issue IMO is how it might complicate the build process, but I think
libpng is standard enough for that not to be a problem. 


-Willem Jan