Re: [csswg-drafts] [css-overflow-4] Line-clamp and IFC (#10323)

The CSS Working Group just discussed `[css-overflow-4] Line-clamp and IFC`, and agreed to the following:

* `RESOLVED: line-clamp establishes an independent formatting context`

<details><summary>The full IRC log of that discussion</summary>
&lt;fantasai> florian: This and the next issue are similar context<br>
&lt;fantasai> florian: for line-clamp we currently have a spec that uses something called 'continue: discard' which invokes fragmentation<br>
&lt;fantasai> florian: some discussion about an alternative approach that relies on visibility-hidden type thing instead<br>
&lt;fantasai> florian: awhile back we resolved to spec both and figure it out<br>
&lt;fantasai> florian: So Andreu has been prototyping both<br>
&lt;fantasai> florian: and we are developing spec for both<br>
&lt;fantasai> florian: We're looking at cases where the effects are accidentally differnet rather than intentionally<br>
&lt;fantasai> florian: Trying to harmonize them where possible<br>
&lt;fantasai> florian: this is one o them.<br>
&lt;fantasai> florian: When we initially drafted line-clamp using continue: discard<br>
&lt;fantasai> florian: we decided it shouldn't automatically become an independent formatting context<br>
&lt;fantasai> florian: it seemed possible to do so; and authors could always opt in using e.g. `display: flow-root`<br>
&lt;fantasai> florian: Driven by making it more nice, not by specific use cases<br>
&lt;fantasai> florian: Andreu found it was significantly simpler to implement if it was an independent formatting context<br>
&lt;fantasai> florian: so proposal is to do that instead<br>
&lt;fantasai> andreubotella: -webkit-line-clamp creates an independent formatting context due to creating a flexbox<br>
&lt;fantasai> andreubotella: For continue:discard there's also an aspect of complexity<br>
&lt;fantasai> andreubotella: it is assumed that every fragmentation container is an IFC<br>
&lt;fantasai> andreubotella: not clear what happens to floats if you have them break in the middle of a fragmentation container that isn't an IFC<br>
&lt;fantasai> andreubotella: Perhaps fragmentation spec that maybe all fragmentation containers should be IFC<br>
&lt;florian> s/making it more nice/making it more generic<br>
&lt;fantasai> andreubotella: When implementing it, it was clear that assuming IFC was so much easier that I didn't even attempt to not<br>
&lt;fantasai> andreubotella: For continue:collapse the considerations are different<br>
&lt;fantasai> andreubotella: I visualized that everything after clamp point should work like there's no content in the tree beyond the clamp point<br>
&lt;fantasai> andreubotella: That means clamped floats should not affect the outside<br>
&lt;fantasai> andreubotella: but what happens within the clamped function? should those floats affect each other?<br>
&lt;fantasai> andreubotella: in the end it was a lot easier to just not have that interaction with the outside of the line-clamp container by making it an IFC also<br>
&lt;emilio> q+<br>
&lt;fantasai> andreubotella: It could still be possible to implement, but would be significantly more complex to implement<br>
&lt;fantasai> andreubotella: and as Florian said, there's no significant use case for not making IFC<br>
&lt;astearns> ack emilio<br>
&lt;fantasai> iank_: It'll also be a lot easier for developers to transition to the new line-clamp because existing prefixed version establishes IFC<br>
&lt;fantasai> emilio: Agree<br>
&lt;astearns> ack dbaron<br>
&lt;fantasai> dbaron: The argument that you made at the end, that we don't want floats clipped by line-clamp to influence floats outside, seems like a good theoretical argument for why this is a sensible behavior that fits with everything else<br>
&lt;fantasai> dbaron: so I'm also in favor<br>
&lt;fantasai> astearns: Proposed resolution that line-clamp establishes an independent formatting context<br>
&lt;fantasai> emilio: When applied to blocks it creates an IFC<br>
&lt;dbaron> a BFC<br>
&lt;dbaron> (block formatting context)<br>
&lt;fantasai> RESOLVED: line-clamp establishes an independent formatting context<br>
&lt;dbaron> (I had just asked about whether we were talking about a block formatting context.)<br>
</details>


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Received on Wednesday, 12 June 2024 13:52:07 UTC