Re: [csswg-drafts] [css-gaps-1] Computed value of column-rule-width with none|hidden style and lists of values (#11494)

The CSS Working Group just discussed `[css-gaps-1] Computed value of column-rule-width with none|hidden style and lists of values`, and agreed to the following:

* `RESOLVED: Do the above.`

<details><summary>The full IRC log of that discussion</summary>
&lt;TabAtkins> kbabbitt: now it's decorations<br>
&lt;TabAtkins> kbabbitt: first, there's some behavior defined in multicol where if column-rule-style is none|hidden, column-rule-width is 0<br>
&lt;TabAtkins> kbabbitt: i'm extending those properties to allow multiple values to allow alternating/etc<br>
&lt;TabAtkins> kbabbitt: how do we accommodate the multicol behavior?<br>
&lt;TabAtkins> kbabbitt: two beahvior<br>
&lt;TabAtkins> kbabbitt: one is, if there's exactly one value and it's non/hidden, width is 0<br>
&lt;TabAtkins> kbabbitt: two is, if it contains multiple values and they're *all* none/hidden, width computes to 0<br>
&lt;TabAtkins> kbabbitt: lean toward first just to minimize beahvior needed for back compat<br>
&lt;TabAtkins> astearns: what do we lose if we don't do 2?<br>
&lt;fantasai> TabAtkins: Very minor concern (agree 1 is probably better) -- when we have behaviors that depend on list of values, can trip over it<br>
&lt;fantasai> TabAtkins: once you add more values<br>
&lt;fantasai> TabAtkins: ways to work around it, e.g. repeat your style and alternate<br>
&lt;astearns> ack fantasai<br>
&lt;TabAtkins> fantasai: is this a case wher eth eused value of the affected liens are still 0, right? so this is just about computed value of the width property?<br>
&lt;TabAtkins> kbabbitt: yeah<br>
&lt;TabAtkins> fantasai: this isn't inherited, so people probabyl won't care<br>
&lt;florian> q?<br>
&lt;TabAtkins> TabAtkins: good argument for the discontinuity not mattering<br>
&lt;emilio> q+<br>
&lt;TabAtkins> fantasai: maybe we could even just change the multicol rule behavior, seems less likely for it to be something people are depending on it<br>
&lt;TabAtkins> kbabbitt: could do a stud<br>
&lt;TabAtkins> fantasai: probably not that important, but maybe good<br>
&lt;astearns> s/stud/study/<br>
&lt;TabAtkins> fantasai: i could imagine not computing to 0 behind useful so you could inherit to children. maybe that's too weird<br>
&lt;astearns> ack emilio<br>
&lt;fantasai> s/could/could explicitly/<br>
&lt;TabAtkins> emilio: on the one hand, existing behavior is consistent with outline-width and border-width<br>
&lt;TabAtkins> emilio: on the other hand, i'm not a fan of that behavior<br>
&lt;TabAtkins> emilio: so i have a slight preference to try and get rid of the weird behavior if we can<br>
&lt;TabAtkins> fantasai: the used value is always 0 regardless, this is just computed value<br>
&lt;TabAtkins> emilio: 'border' i doubt we could change, without changing gCS()<br>
&lt;TabAtkins> emilio: border used to be a "used value" property<br>
&lt;fantasai> s/changing/special-casing/<br>
&lt;TabAtkins> emilio: so we'd probably still need to special-case it if we wanted to get rid of this in general<br>
&lt;TabAtkins> emilio: common for people to just fetch the border-width and padding from gCS(), so needs to stay 0<br>
&lt;TabAtkins> emilio: but maybe could change outline as well<br>
&lt;TabAtkins> fantasai: what if we said hidden/none no longer affect border/outline/column-rule<br>
&lt;TabAtkins> fantasai: but gCS() returns 0 on these properties if the style is hidden/none<br>
&lt;TabAtkins> emilio: i think we could get away with that<br>
&lt;fantasai> s/affect/affect computed value of/<br>
&lt;TabAtkins> florian: problem is gCS() isn't computed value, it's "resolved value". Proposal is computed value doesn't set to 0, only resolved value. So inheritance sitll gets the proper value.<br>
&lt;TabAtkins> kbabbitt: so still a question of how we do that for gap-rule<br>
&lt;TabAtkins> TabAtkins: emilio suggested we can do this resolved-value hack only for border, just fix outline and column-rule ot normal<br>
&lt;TabAtkins> emilio: [outlines that]<br>
&lt;TabAtkins> emilio: we could add it into outline/column-rule for single values *if needed*<br>
&lt;TabAtkins> emilio: if you inherit the whole border it does what you want, if you inherit border-width of 0 and then reset border style, uh, why?<br>
&lt;fantasai> TabAtkins: So we remove the current to-zero computation for all these properties. Instead do it in gCS only for border-width only.<br>
&lt;fantasai> TabAtkins: If we need to, go back and apply for outline/column-rule if needed for compat<br>
&lt;TabAtkins> astearns: objections?<br>
&lt;TabAtkins> RESOLVED: Do the above.<br>
</details>


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Received on Friday, 31 January 2025 21:41:01 UTC