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Re: [whatwg] Canvas in Workers

From: Ian Hickson <ian@hixie.ch>
Date: Wed, 9 Jan 2013 20:38:56 +0000 (UTC)
To: James Robinson <jamesr@google.com>
Message-ID: <Pine.LNX.4.64.1301092038210.12992@ps20323.dreamhostps.com>
Cc: WHAT Working Group <whatwg@whatwg.org>, Stephen White <senorblanco@chromium.org>
On Wed, 9 Jan 2013, James Robinson wrote:
> On Wed, Jan 9, 2013 at 11:59 AM, Ian Hickson <ian@hixie.ch> wrote:
> > On Wed, 9 Jan 2013, Stephen White wrote:
> > > >
> > > > Right now by 2d canvases are effectively single buffered. At the 
> > > > appropriate time a copy of the canvas is made and passed to the 
> > > > compositor. This copy is slow, especially on mobile.
> > >
> > > Currently, to lower the VRAM footprint and improve performance, we 
> > > don't do a copy in 2d canvas.  We temporarily transfer ownership of 
> > > the texture to the compositor at commit time, and block the renderer 
> > > until the composite is complete.  That may change, however.
> >
> > Good to know, thanks. Should this change, or should there be a desire 
> > for a mode where it looks like after the commit the buffer is cleared, 
> > please do let me know.
> 
> We (chromium) would really appreciate a way for the author to express 
> clear-after-commit.  I think this would match up with what authors 
> frequently want, since many canvas pages clear the canvas at the start 
> of the next frame anyway, but allow for more flexibility and 
> optimizations in our implementation.

Noted: 
http://wiki.whatwg.org/wiki/New_Features_Awaiting_Implementation_Interest

-- 
Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
Received on Wednesday, 9 January 2013 20:39:22 GMT

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