Re: [csswg-drafts] [css-fonts] Clarify/reconsider interaction of new font-size-adjust options with writing modes (#6288)

The CSS Working Group just discussed `font-size-adjust vs writing modes`, and agreed to the following:

* `RESOLVED: Switch ic and ch to ic-width/ic-height/ch-width`

<details><summary>The full IRC log of that discussion</summary>
&lt;fantasai> Topic: font-size-adjust vs writing modes<br>
&lt;fantasai> github: https://github.com/w3c/csswg-drafts/issues/6288<br>
&lt;fantasai> jfkthame: Was working on implementing in Gecko, and it occurred to me that the behavior that falls out for the new ch and ic units probably isn't what we really want<br>
&lt;fantasai> jfkthame: if you set font-size-adjust: ch 0.4, for example, and then use vertical writing mode with upright typesetting<br>
&lt;fantasai> jfkthame: you'd get completely different scaling<br>
&lt;fantasai> jfkthame: Seems that would be unexpected and undesirable<br>
&lt;fantasai> jfkthame: Expectation would be that font + font-size-adjust should give consistent results<br>
&lt;fantasai> jfkthame: So my suggestion is that it applies in the horizontal axis<br>
&lt;fantasai> jfkthame: so not quite the same as the units<br>
&lt;fantasai> jfkthame: so maybe need to rename to make more explicit what they are<br>
&lt;fantasai> astearns: I think I'd like ch-width name<br>
&lt;fantasai> astearns: very explicit<br>
&lt;fantasai> jfkthame: We'd have the option of introducing a ch-height for vertical mode, but usage expected to be quite different<br>
&lt;fremy> fantasai: that would be more difficult than helpful<br>
&lt;fremy> fantasai: the vast majority of the authors wont need that second number<br>
&lt;fremy> fantasai: I would be ok with it if it is optional<br>
&lt;fremy> astearns: I think that was the proposal<br>
&lt;fantasai> fantasai: and sets to no effect<br>
&lt;fremy> fantasai: currently if you wanted to have an effect in the vertical axis, we have a syntax for two values<br>
&lt;fremy> fantasai: the disadvantage of that is that you might want different values for the different axes<br>
&lt;fremy> fantasai: but given few people would want to use two values<br>
&lt;fremy> fantasai: maybe we should just have one value and be clear about what it means<br>
&lt;fantasai> fantasai: and when would you know which one you want, if both are specified?<br>
&lt;fantasai> astearns: were we going to have ic-height and ic-width that can set at the same time?<br>
&lt;fantasai> jfkthame: no, just one at a time<br>
&lt;fantasai> astearns: So propoed resolution is to replace ic and ch with ic-width ic-height and ch-width<br>
&lt;fantasai> astearns: to lock things to the appropriate axis and make that explicit<br>
&lt;fantasai> fantasai: The one thing we might consider is adding 'ic' and having it compute to 'ic-width' or 'ic-height' as appropriate to the writing mode and then inherit as that computed value<br>
&lt;fantasai> fantasai: worth consideration, but I haven't thought about it much<br>
&lt;fantasai> astearns: but whatever value you add to that ic would be based on one or other metric, so unlikely to have single value that works for both<br>
&lt;fantasai> fantasai: unless you're using 1em, in which case no effect execpt for non-square fonts anyway...<br>
&lt;fantasai> jfkthame: [...]<br>
&lt;fantasai> jfkthame: Could look into it, but doesn't seem worth the complexity<br>
&lt;fantasai> RESOLVED: Switch ic and ch to ic-width/ic-height/ch-width<br>
</details>


-- 
GitHub Notification of comment by css-meeting-bot
Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/6288#issuecomment-862547125 using your GitHub account


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

Received on Wednesday, 16 June 2021 16:55:28 UTC