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Re: [whatwg] Canvas in Workers

From: James Robinson <jamesr@google.com>
Date: Wed, 9 Jan 2013 12:18:50 -0800
Message-ID: <CAD73md+URo+LqOJVYoXQDnOAobkdxuXUYVNQ3UU4cfKVaa22kQ@mail.gmail.com>
To: Ian Hickson <ian@hixie.ch>
Cc: WHAT Working Group <whatwg@whatwg.org>, Stephen White <senorblanco@chromium.org>
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.

- James

>
> Would still love input from any other vendors, too.
>
> --
> Ian Hickson               U+1047E                )\._.,--....,'``.    fL
> http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
> Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
>
Received on Wednesday, 9 January 2013 20:28:59 GMT

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