[css-anchor-position-1] Working with Scroll Driven Animations #9379
Description
The spec currently says that the anchored element position is determined as if all of the scrollers are scrolled to the top. The scrolling adjustment is then made by a snapshot scroll offset. I think this works fine for the common scrolling case.
However, with addition of scroll driven animations, a scroll offset can now affect a progress of an animation which can affect far more than just a translation. It isn't clear if the spec means that these animations should be at 0% progress because the scroll is at the top. I think it's worthwhile to call out scroll driven animations explicitly and figure out how to handle the interaction.