Re: [csswg-drafts] [css-animation] Motion Blur (#3837)

If we target a specific element/layer, I think we could expose a previous transform (e.g. 1/60th of a second ago) which would enable a shader to compute the previous location of that pixel and blur along that direction vector. Of course for spinning things this wouldn't quite be right (blurring across a line rather than an arc) but the error in most cases might not be too noticeable.

> * The property should have no side effects; it doesn't force a compositor layer on its own & doesn't change rendering for non-moving elements.

I suspect that we will need to force a compositor layer whenever the blur is applied. This is similar to opacity where because the shader relies on colors from the buffer it will require a rendering pass when applied to multiple layers. Right now opacity is in this strange state where we force a stacking context when it's not 1 but this is often surprising for developers as the stacking order of items changes when you [start animations or change opacity](https://jsbin.com/cezohom/edit?html,css,js,output). I think always flattening would be less surprising.

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Received on Wednesday, 5 June 2019 18:07:06 UTC