[csswg-drafts] [css-scroll-anchoring-1] Unclear whether a 0-size element at edge of region is eligible as anchor node or not (#3483)

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

== [css-scroll-anchoring-1] Unclear whether a 0-size element at edge of region is eligible as anchor node or not ==
https://drafts.csswg.org/css-scroll-anchoring/#anchor-node-selection defines "fully visible" and "fully clipped" as follows:
> A DOM node N is fully visible in a scrolling box S if N’s scroll anchoring bounding rect is entirely within the optimal viewing region of S.
> A DOM node N is fully clipped in a scrolling box S if N’s scroll anchoring bounding rect is entirely outside the optimal viewing region of S. 

This leaves an edge case undefined (depending on how you interpret "within" vs. "outside"):
**What if `N`'s rect has size (0,0) and is positioned exactly on the edge of the optimal viewing region?  Is that empty rect considered "entirely within" or "entirely outside" the region?**


(This choice will have a user-noticeable impact; if such a node is "entirely within", then the algorithm will terminate and chooses this 0-sized node `N`; but if it's "entirely outside",, then the algorithm will proceed & choose some other node.)

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/3483 using your GitHub account

Received on Friday, 4 January 2019 21:32:40 UTC