Re: [csswg-drafts] [css-fonts-4] font-kerning:normal and CJK fonts with kerning pairs for fullwidth not well defined (#6723)

Discussing with @MurakamiShinyu, we outlined 5 possible things that an author might want to do:

1. no kerning
2. kern non-CJK† only
3. apply palt/vpal and kern everything
4. apply palt/vpal and kern non-CJK
5. apply palt/vpal and kern nothing

Of these 5, the first 3 seem to be clearly needed; the last two, we're not sure. Either way, the spec should clarify that kerning CJK requires applying palt/vpal as well.

A question raised was whether palt/vpal should be applied via `font-variant-east-asian` where we already have the somewhat-related `proportional-width` keyword. But `font-variant` is fundamentally about alternate glyphs whereas palt/vpal is about spacing, so `font-kerning` is probably a better place to control it.

Possible syntax for these options:
1. `font-kerning: none`
2. `font-kerning: normal`
3. `font-kerning: all` (new keyword)
4. Unclear if we need this (not easy to work around if needed)
5. Unclear if we need this (can use `font-feature-settings` if needed‡)

It might be useful to hear from @macnmm and others if options 4 or 5 are needed.

† The appropriate division here is probably East Asian Wide vs others.
‡ The naive way to do this would be `font-kerning: none; font-feature-settings: "palt"`, but this doesn't handle writing modes correctly, so the correct way to do it would be `font-kerning: all; font-feature-settings: "kern" off, "vkrn" off`.

-- 
GitHub Notification of comment by fantasai
Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/6723#issuecomment-1411487571 using your GitHub account


-- 
Sent via github-notify-ml as configured in https://github.com/w3c/github-notify-ml-config

Received on Wednesday, 1 February 2023 05:25:37 UTC