Re: [css-compositing]new Editor's draft posted

On Tue, May 21, 2013 at 11:16 PM, Robert O'Callahan <>wrote:

> On Wed, May 22, 2013 at 11:40 AM, Rik Cabanier <> wrote:
>> - the backdrop is the stacking context of your ancestor -> this still
>> needs more discussion and is marked as an issue since it could be the
>> ancestor layer.
> I don't see how that helps much. An element's ancestor's stacking context
> could contain all kinds of content below the element, which the browser
> could have assigned to layers in various ways.

Those would have been composited already by the time the element that is
blending, is composited. I don't think that is ever done out of order.
So, all those layers are already in the stacking context/layer so it's
possible to examine the pixels.

Someone mentioned that maybe you should only blend with your parent element
(in effect promote it to a stacking context too), but I think that doesn't
solve the problem either...

> CSS constructs that create groups or layers, is something that developers
>> are getting more familiar with.
>> I realize that browser vendors are hesitant to specify them but it looks
>> that Google is starting to educate its users about them.
>> For instance, layers (and their effect on performance) are discussed at
>> Google IO here:
> I don't think it's a good idea to teach authors to create content
> optimized for one specific rendering implementation.

Yes, the Q & A was touching on that a bit.

Received on Wednesday, 22 May 2013 06:36:29 UTC