I'm not sure I like this proposal. Why is canvas special? Why doesn't <img> get 
an opaque attribute (or flag)? Why not every element?

I don't think the performance benefit, which is mostly going to be on very 
limited hardware, is worth changing the rendering model that is consistent 
across every other part of the Web.

Dean

On 15/03/2013, at 4:53 AM, Stephen White <senorbla...@chromium.org> wrote:

> Hi Dirk,
> 
> There have been at least five options considered, with contributions from 
> Chromium, Adobe and Mozilla so far.  The moz-opaque idea was first floated by 
> Robert O'Callahan from Mozilla, and Ian Hickson offered to spec it if another 
> browser vendor wanted to implement it.  I took him up on that offer, and have 
> made my humble effort to massage it into a concrete proposal in the linked 
> message above.
> 
> After proposing it here, the alternative suggestion is to sync it up with the 
> WebGL syntax, and use a context creation object at getContext() time rather 
> than an attribute on the <canvas> element.  I have no strong feelings about 
> this either way, and I'm working on a patch to try out the WebGL approach (I 
> already have a WebKit patch which implements the platform-independent parts 
> of the opaque attribute approach).  However, if we do go that way, I'd prefer 
> not to make this proposal conditional on changes to the WebGL spec, concerns 
> which I've outlined over on what-wg.
> 
> Stephen
> 
> 
> On Wed, Mar 13, 2013 at 12:30 PM, Dirk Schulze <dschu...@adobe.com> wrote:
> This is a very long thread and I did not see any conclusions or agreement on 
> this thread. Can you summarize the topic and the status on the acceptance 
> level please?
> 
> Greetings,
> Dirk
> 
> On Mar 13, 2013, at 9:15 AM, Stephen White <senorbla...@chromium.org> wrote:
> 
> > Hi WebKittens,
> >
> > I'm planning to implement the canvas "opaque" attribute, as proposed here:  
> > http://lists.w3.org/Archives/Public/public-whatwg-archive/2013Mar/0109.html.
> >
> > This is an attribute that causes the allocation of an opaque backing store 
> > for <canvas>, allowing optimizations at the time the canvas is composited 
> > into the page, such as disabling blending and culling obscured content.  It 
> > is based on the moz-opaque attribute currently shipping in Firefox.
> >
> > I'll be placing the feature behind the build-time flag 
> > ENABLE(OPAQUE_CANVAS).
> >
> > Let me know if you have any comments or concerns.
> >
> > Stephen
> > _______________________________________________
> > webkit-dev mailing list
> > webkit-dev@lists.webkit.org
> > https://lists.webkit.org/mailman/listinfo/webkit-dev
> 
> 
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