[csswg-drafts] [css-overflow-4] Should abspos painting in line-clamp depend only on whether the containing block is before clamp? (#11962)

andreubotella has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-overflow-4] Should abspos painting in line-clamp depend only on whether the containing block is before clamp? ==
When implementing #11379 in Chromium (https://crrev.com/c/6257576), it became clear from @bfgeek's reviews that he and I didn't share the same understanding of how abspos should behave when their containing block is a descendant of the line-clamp container, in the `continue: collapse` case:

- My understanding was that previously, abspos would be hidden if their position in the box tree is after the clamp point, regardless of what their containing block did; and that with the resolution in #11379, this would still be the behavior for abspos whose containing block is a descendant of the line-clamp container. This (minus the #11379 resolution) is the behavior in my spec PR #10816, in the experimental Chromium implementation, and in the WPT tests I wrote while working on that implementation. I think it is also the behavior Firefox had before they rolled back not painting content after clamp as a result of the abspos compat issue.
- Ian's understanding was that whether an abspos gets painted depends entirely on whether its containing block starts before the clamp point. This aligns with [this comment](https://github.com/w3c/csswg-drafts/issues/7708#issuecomment-1747840639) on the `continue: collapse` issue.

I don't think we ever discussed this in the CSSWG (although I think we have discussed some of this in hallway conversations in TPAC or F2F's), and the only thing that came close to this in the various issues and PR's is that comment by @tabatkins about the painting of abspos depending on their containing block, and my WIP PR that has the other behavior. So we should resolve on something.

@emilio @frivoal @alanbaradlay

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/11962 using your GitHub account


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Received on Wednesday, 19 March 2025 11:38:32 UTC