svgeesus commented 3 years ago

New charter proposal, reviewers please take note.

Charter Review

What kind of charter is this? Check the relevant box / remove irrelevant branches.

[ x] New WG
If this is a new WG or IG charter request, link to [Advance Notice](), and any issue discussion:

No Advance Notice yet. Discussion at 26 Apr ColorWeb CG meeting

Ready for Advance Notice soon.

Horizontal Reviews: apply the Github label "Horizontal review requested" to request reviews for accessibility (a11y), internationalization (i18n), privacy, and security. Also add a "card" for this issue to the Strategy Funnel.

Communities suggested for outreach:

As noted in the charter, the previous specification developers, the proposers of the (rejected, but since widely implemented) APNG extension, the libpng developers, ColorWeb CG, ISO JTC 1/SC 24. Possibly ICC.

Known or potential areas of concern:

Avoiding invalidating existing images or image encoders/decoders
Small maintenance update with a few, carefully considered, new features
Possibility to update the existing ISO Standard
Previous REC was 2003 under CPP
No previous W3C WG

Where would charter proponents like to see issues raised? (this strategy funnel issue for horizontal review, charter-drafts repo for other issues)

michael-n-cooper commented 3 years ago

APA is interested in this work but cannot tell what features might overlap with accessibility. The charter mentions "selected new features" but does not specify them, nor provide a link. Therefore we request additional information before signing off on this charter.

svgeesus commented 3 years ago

The charter mentions "selected new features" but does not specify them, nor provide a link.

Two features are mentioned in the background section, both with links. The Working Group might choose to add others, though; it is not an exhaustive list.

What additional information do you require?

himorin commented 3 years ago

No comment/request from i18n.

svgeesus commented 3 years ago

Thanks, @himorin !

samuelweiler commented 3 years ago

What extension points (e.g. a version number) does the existing PNG spec provide? Seeing none, I'm wondering whether the backwards-compatibility constraint is too constraining and we instead need a two-part solution: apply the errata to PNG and develop a PNG2 with a different magic number and some extension points for the future.

No security or privacy issues. Filed a minor issue https://github.com/w3c/charter-drafts/issues/357/.

svgeesus commented 3 years ago

What extension points (e.g. a version number) does the existing PNG spec provide?

It is not versioned as an extension mechanism. Instead, it is explicitly extensible, with rules on what do do with unknown chunks and how to tell if an unknown chunk is critical (image cannot be displayed without it) or ancillary.

I'm wondering whether the backwards-compatibility constraint is too constraining

No. It has worked well for 25 years, and was explicitly listed in the previous joint work with ISO.

Thanks for your comments, and for confirming no privacy or security concerns!

svgeesus commented 3 years ago

@michael-n-cooper ?

svgeesus commented 3 years ago

Advance notice sent 18 May 2021

svgeesus commented 3 years ago

@michael-n-cooper you requested "additional information" on new features 21 days ago. I responded the same day indicating that the two known new features were already described and linked from the charter; and that we can't describe unknown new features, and asking what info you need beyond that. Could you please respond?

michael-n-cooper commented 3 years ago

The information in the Background section is a useful introduction to the reasons for forming this WG. However, that is not part of the charter template and reads in a very "non-normative" way. Therefore we do not think it sufficiently defines the proposed chartered work. The scope should be more detailed about the meaning of "selected new features", at the very least mentioning the ones in the background, and also giving any indicators possible to other work currently on the horizon. APA may have a great interest in horizontal review and / or feature development, or it may have very little, depending on the nature of the work. More detail on that would inform subsequent comments about the level of coordination APA requests to be mentioned in the charter.

Non-exhaustive set of possible features that might be in scope that would interest APA:

Metadata fields that impact accessibility
Color adjustment capabilities, especially for indexed-color pngs

svgeesus commented 3 years ago

Thanks, @michael-n-cooper

In response to requests from many AC reps, we are moving general introductory material out of the scope section and into an introduction. This aids legal review. But I do see your point about specifics.

As discussed on this weeks strat call, we don't want to over-constrain the group to only add the two features listed.

The two listed are the only ones on the horizon at this stage.

PNG already has UTF-8 text metadata, and some of the content in that might be helpful. However, the feature is less used in practice due to

Authoring tools rarely offering a way to fill it in
Image optimization tools reducing file size by dropping it.

PNG also has optional, named palettes

svgeesus commented 2 years ago

@wseltzer Still Agenda+ to try and close off the a11y review. W3m review is now complete so this is blocking the start of AC review. @michael-n-cooper

svgeesus commented 2 years ago

Per @plh today, W3M approved move ahead.

svgeesus commented 2 years ago

https://www.w3.org/Team/w3m/tracker/actions/2265

wseltzer commented 2 years ago

Group formed: https://www.w3.org/groups/wg/png

w3c / strategy

PNG Working Group #268

Charter Review