Re: [csswg-drafts] [scroll-animations-1] Interaction of content-visibility: auto and ScrollTimeline.currentTime (#7545)

The CSS Working Group just discussed `c-v:auto and scrollTimeline.currentTime`, and agreed to the following:

* `RESOLVED: close no change`

<details><summary>The full IRC log of that discussion</summary>
&lt;TabAtkins> Topic: c-v:auto and scrollTimeline.currentTime<br>
&lt;TabAtkins> github: https://github.com/w3c/csswg-drafts/issues/7545<br>
&lt;TabAtkins> ydaniv: c-v:auto optimizes experience of mostly loading time<br>
&lt;TabAtkins> ydaniv: UA can handle internally<br>
&lt;flackr> q+<br>
&lt;TabAtkins> ydaniv: if there is a scroller that might change height during scroll, because content with c-v:auto comes into view and expands, it can change currentTime and cause jumps<br>
&lt;bramus> q+<br>
&lt;TabAtkins> ydaniv: so maybe if UA can detect that c-v:auto is being used in a scroller serving as a timeline, do less of this optimization so there's no surprises<br>
&lt;emilio> q+<br>
&lt;astearns> ack flackr<br>
&lt;TabAtkins> flackr: I think this would be a big perf footgun<br>
&lt;TabAtkins> flackr: I think having that disconnect is consistent with what the dev observes thru scrollOffset, so it's not surprisig to me<br>
&lt;TabAtkins> flackr: but if we are concerned, could imagine using c-i-s rather than real size<br>
&lt;bramus> q-<br>
&lt;TabAtkins> emilio: Yeah seems weird to opt out of c-v:auto<br>
&lt;TabAtkins> emilio: author can do that themselves<br>
&lt;TabAtkins> emilio: side effect si unfortunate, but would rather do it rather than add a footgun where your page is all c-v:visible bc you put an animation on the root scroller<br>
&lt;TabAtkins> TabAtkins: details on c-i-s?<br>
&lt;emilio> ack emilio<br>
&lt;TabAtkins> flackr: Like calculate scrollable area as if everything was its c-i-s size. different version of scrollTop/Height<br>
&lt;TabAtkins> emilio: seems tricky<br>
&lt;TabAtkins> flackr: Yeah very tricky, unsure if even possible<br>
&lt;TabAtkins> emilio: would need to do a pass on the contents of the scroller...<br>
&lt;TabAtkins> emilio: i'd rather not<br>
&lt;TabAtkins> flackr: i'd rather if we did that we did it more generally, actually change scrollTop/etc that way<br>
&lt;TabAtkins> iank_: agree, that's a can of worms we dont' want to do<br>
&lt;TabAtkins> astearns: so it sounds like response so far is close no change. that all right with you, ydaniv?<br>
&lt;TabAtkins> ydaniv: yeah<br>
&lt;TabAtkins> RESOLVED: close no change<br>
</details>


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Received on Wednesday, 3 August 2022 15:36:16 UTC