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Re: [fxtf-drafts] [filters] Backdrop filters should not use BackgroundImage

From: Dirk Schulze via GitHub <sysbot+gh@w3.org>
Date: Tue, 24 Apr 2018 05:15:51 +0000
To: public-fxtf-archive@w3.org
Message-ID: <issue_comment.created-383805859-1524546950-sysbot+gh@w3.org>
Run 2 different tests:
* One with 2D transform animation
* One with 3D transform animation and perspective.

## 2D tranform animation
https://codepen.io/krit/pen/XqXvyo

* Once an animation with a transform gets specified and starts, the group starts getting isolated. So the 2nd circle in the first example gets white on hover.
* `backdrop-blur` continues to get the content from the backdrop.

This actually makes sense. Even when split into compositing layers, the implementation still has access to the different "raster images"/compositing layers and can composite those for the backdrop blur filter. At least when you implement backdrop-blur in the paint pipeline you have.

## 3D transform animation with perspective
https://codepen.io/krit/pen/zjrgmy
Then I modified the example with a `perspective` property and a `rotateX` (I always struggle to make things look 3D but it works for this test 😆 ).

* On hover, the `backdrop-filter` stops working. This is expected since we no longer have two 2D planes that simply needs to get composited.

## Conclusion
The question is:
* Do we make `backdrop-filter` stop at `isolation` as `filter` and `mix-blend-mode` do or
* do we define a new isolation term based on the existence of perspective?

And extended question:
* If we go with the new isolation term, can we have it for `BackgroundImage` too?

-- 
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Please view or discuss this issue at https://github.com/w3c/fxtf-drafts/issues/53#issuecomment-383805859 using your GitHub account
Received on Tuesday, 24 April 2018 05:15:58 UTC

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