On Thu, May 23, 2013 at 4:02 PM, Rik Cabanier <cabanier@gmail.com> wrote: > After talking this over with our engineers, it turns out that the > invisible 'layers' that browsers create, are not actually a problem. > This is because they are composited in order and not as a tree (at least > on webkit and blink). > For instance, if you have content like this: > > <video>...</video> > <div> > > <p>...</p> > > <p style="mix-blend-mode">... > > there will be 3 layers on the back-end: one for video, one for the <div> > and for the <p> with the blending. > This content will be composited as a list so <p> will composite and blend > with the composited result of <video> + <div> which is the desired behavior. > Well no, it depends. Sometimes it will render in the way you say here, but sometimes we may blend the <p> together with the <div> before blending that with the <video> or we may put different subsets of these layers into separate intermediate surfaces. We may be forced to blend the <div> and the <p> together without involving the <video>'s contents if the <div> has a transform-style: preserve3D, for example. Whether this produces any observable difference in the final output depends on exactly why you are depending on the draw order - in general, you really shouldn't. - James > > I updated the spec and removed that particular issue. I also worded it so > blending will happen between stacking context (which is what David Baron > suggested in an earlier email) > There will still be work needed on the implementation side to plumb this > i, but I think this will suffice for the specification. > > Rik > >
Received on Thursday, 23 May 2013 23:58:23 UTC