Re: [fxtf-drafts] [filter-effects-2] Backdrop filters should not use BackgroundImage (#53)

I realize I'm a bit late to the party, but I'm really glad to see motion in the direction of a formal definition of "backdrop", and I think Mason's doc also does a great job of outlining possible problem scenarios that we should be able to iterate through and reach consensus on what should happen.  I suspect everyone on the thread would agree that at minimum the root element should form the root of the backdrop, so then it's just the other bullets we'll need to agree on :)

I also share concerns about the restrictions surprising developers or blocking potentially valid usage, so I think it will be good to reason out why each of these scenarios can't be solved or alternatively how to overcome that challenge.  I see some of this discussion in Mason's doc already - what would be the most productive way to open up discussion/iterate on each of these points?  Maybe we can resolve to start by adding an initial formal definition of "backdrop" or "backdrop root" to the spec with minimal restrictions (just root element) and then open issues for each additional restriction we'd like to consider for discussion?  Or just comment directly in Mason's doc and later try for a resolution on the full definition all at once?  Or something else?

A final couple thoughts:
* I think it makes a lot of sense for mix-blend-mode's "backdrop" to ultimately share a definition with backdrop-filter's "backdrop" as others mention above (hopefully at least somewhat more relaxed than stacking context).
* My instinct is that relaxing restrictions on the definition of backdrop should generally be a compatible change for content authored against the more restrictive definition.  Both because it's primarily a visual-only change but also I'm having a hard time hypothesizing a scenario where a developer takes a hard dependency on content behind the element in question dodging the filter/blend.

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Received on Wednesday, 6 February 2019 00:05:13 UTC