Re: [csswg-drafts] [css-scroll-snap] Scroll snap areas for fragmented boxes (like in css-multicol) (#5911)

So there are two issues here; the one being asked, and the one being alluded to by the e-reader use case mentioned in the OP. The latter is addressed in #6017.

For the question of how to snap to a fragmented element, there are a few options:
1. draw the bounding box of all the fragments, and snap that area
2. have each fragment be an independent snap area
    
The first is roughly Chrome's current behavior, the second is Firefox's.

If we do the second, there's then the question of which fragment to snap to when an element is targeted/scrolled-into-view:
2a. the first fragment is always the initial snap
2b. the first fragment is snapped when "start" aligned, the last is snapped when "end" aligned, the middle (???) fragment when "center" aligned

2b has some complications (which fragment is the "middle"? just count by index? weight by size? if # of fragments is even, do we bias toward start or end?) and can be a little confusing if you're start-snapping in one axis and end-snapping in another (this is already handled by the spec, it's just potentially confusing to authors).

So I propose either 1 or 2a, but don't have a strong opinion between them. There might also be other options we haven't thought of.

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Received on Thursday, 18 February 2021 19:53:45 UTC