Re: [csswg-drafts] [css-anchor-position-1] Better reusability of anchor names (#9045)

Re @tigrr https://github.com/w3c/csswg-drafts/issues/9045#issuecomment-1645206072:

The `closest` specifier doesn't seem to work with the current model.

Anchor Positioning is based on Absolute Positioning. When laying out the anchored element, the context is its containing block, which is its parent in the box tree. When querying an anchor name, we are not supposed to see anything outside the containing block. In other words, we are not supposed to see any ancestor other than the parent node.

Also, the `next`/`following` specifier may violate the [acceptable anchor element](https://www.w3.org/TR/css-anchor-position-1/#acceptable-anchor-element) criteria, which require that an element must be laid out completely after its anchor (and therefore, the anchor relationship in the entire tree is acyclic), so we are not always able to anchor to a following sibling.

Btw, the current spec doesn't even allow using the containing block as the anchor element. So the only anchors we can use are siblings and their descendants.

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Received on Wednesday, 30 August 2023 22:04:54 UTC