[whatwg] Hardware accelerated canvas

Ashley Gullen ashley at scirra.com
Tue Sep 4 11:04:55 PDT 2012

It sounds like the real issue is mobile:
- it seems pretty difficult to make a desktop lose a context
- most mobile browsers still use software rendering, or at least haven't
had GPU acceleration very long, so there are unlikely to be bug reports
about it
- it sounds like mobile devices lose contexts much more easily
Even so, I think an 'onforcerepaint' / 'onneedredraw' / 'onreset' type
event is the best way to handle this.  If it's really that rare, most devs
can ignore the event.  If it happens a lot (e.g. on mobile), it will
gradually become common knowledge, built in to frameworks, etc.


On 4 September 2012 18:49, Justin Novosad <junov at chromium.org> wrote:

> On Tue, Sep 4, 2012 at 10:22 AM, Mark Callow <callow_mark at hicorp.co.jp
> >wrote:
> >
> > It is not a rare occurrence on mobile devices. On my tablet WebGL app's
> > lose their context every time the tablet goes to sleep. Since the
> > timeout is so short, it only take a brief distraction and "poof!" the
> > tablet is asleep. The loss can happen while the application is in the
> > middle of drawing the canvas.
> >
> >
> It seems like this is much more of a problem on mobile OSes. On win7, I
> tried unsuccessfully to hose GPU-accelerated 2D canvases in IE and Chrome.
>  The OS (or is it the graphics driver?) is doing a good job of making 2D
> canvas render buffers persist through various GPU calamities such as system
> hibernation and remote desktop sessions.  So, is context loss even an issue
> on any modern desktop OS?  Can anyone reliably repro a 2D canvas context
> loss on Windows (Vista or 7), or MacOS X with up to date drivers and a
> current version of any browser?

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