Re: [css-transforms] CSS3D breaks with opacity flattening

On 22/09/16 12:41 PM, Tien-Ren Chen wrote:
> I don't think group opacity can be properly defined without
> flattening. What if some planes in the group are non-opaque themselves
> and later intersect with non-opaque planes outside of the group?
>
> Specifically, how would you define the expected behavior for this
> particular example? http://jsbin.com/tepixi/
>
Right, I totally agree with this.

Opacity *does* require flattening, and if there are planes outsides the 
group that want to be sorted with planes within the group, there isn't a 
way to properly define behaviour.

My point is that when we do the flattening for opacity, we should do so 
in the coordinate space of the root element of the preserve-3d context 
(by propagating ancestors transforms down through the opacity), since 
this results in better rendering for the cases where sorting across the 
opacity boundary isn't required (and there *is* a reasonable definition 
for the right behaviour).

For cases like yours, there is no right behaviour, so we're just picking 
which fallback sucks the least.

- Matt

Received on Thursday, 22 September 2016 01:28:55 UTC