Re: Getting APNG support into libpng

Hi Chris,

I completely agree.  APNG has been around so long, and is now so widely
used and supported, that it just seems strange that libpng doesn't support it.

Michael

On Wed, 5 May 2021 at 17:46, Chris Lilley <[email protected]> wrote:
>
> The APNG extensions failed their original vote, and an attempt to
> restart discussions some years ago failed from lack of discussion.
>
> Thus, libpng does not have any APNG support and unofficial patches are
> merged in by various Linux distros, individual maintainers of image
> editing tools, and Web browsers.
>
> However, APNG is now very widely supported so this is a bad situation.
> https://caniuse.com/apng
>
> Meanwhile the PNG specification is badly needing maintenance. There are
> many errata reported since 2003. To help with that, I forked the W3C PNG
> specification to make an Editors Draft.
> https://w3c.github.io/PNG-spec/
>
> Each reported erratum is raised as a GitHub issue and the clear and
> obvious ones I have rolled into the Editors Draft so the changes can be
> viewed in place. The others need to be discussed.
> https://github.com/w3c/PNG-spec/issues
>
> I don't think the original PNG mailing list is the right way to handle
> specification maintenance anymore. The discussion procedure is baroque,
> there is a poor record of discussing or adopting proposals, and momentum
> has ground to a halt. I think an open W3C Working Group is the better
> way to handle this.
>
> Beyond just maintenance though, there is a clear need to re-align the
> PNG specification with widely-implemented reality, especially as regards
> APNG.
>
> An updated PNG Specification which incorporates APNG would then allow
> libpng to incorporate support directly, rather than a plethora of ad-hoc
> patches, forks, or other means to support it.
>
> Cosmin, I would really value your comments on this path forwards.
> Continued alignment between the PNG specification and libpng is very
> important. libpng is being held back by the brokenness of the current
> PNG spec maintenance process. It should not be.
>
> (I posted this earlier to
>   APNG support on main libpng library? #267
>   https://github.com/glennrp/libpng/issues/267 )
>
> --
> Chris Lilley
> @svgeesus
> Technical Director @ W3C
> W3C Strategy Team, Core Web Design
> W3C Architecture & Technology Team, Core Web & Media
>
>
>
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