W3C home > Mailing lists > Public > www-style@w3.org > May 2013

[css-compositing] new Editor's draft posted -> update

From: Rik Cabanier <cabanier@gmail.com>
Date: Thu, 23 May 2013 16:02:03 -0700
Message-ID: <CAGN7qDA_Jy6WKD5UOEZtGX-UV4mhzRuQNfsBF7rY7Wfqvahm+Q@mail.gmail.com>
To: public-fx@w3.org, www-style list <www-style@w3.org>, www-svg <www-svg@w3.org>, David Baron <dbaron@dbaron.org>, "Robert O'Callahan" <robert@ocallahan.org>
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.

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

On Tue, May 21, 2013 at 8:40 PM, Rik Cabanier <cabanier@gmail.com> wrote:

> As a quick recap, people voiced concerns about the following issues before:
> - background-blend-mode blends with the entire backdrop of the element
> - does mix-blend-mode create a stacking context?
> - what is the backdrop of mix-blend-mode?
>
> The spec was changed so:
> - images that have background-blend-mode applied will only blend between
> themselves and the background color
> - mix-blend-mode always creates a stacking context
> - 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.
>
> 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.
>
>
Received on Thursday, 23 May 2013 23:02:30 UTC

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