[whatwg] Hardware accelerated canvas

[Boris Zbarsky]

On 9/4/12 1:20 PM, Glenn Maynard wrote:
> The only reason I can think of switch renderers, instead of
> snapshotting, is to deal with losing the context *mid*-render, while a
> script is still drawing.  (That seems like a problem so rare as to be
> almost theoretical, though.)

The main reason to switch renderers instead of snapshotting is that if 
you default to software rendering and then upgrade to GPU you just need 
to take your buffer and dump it to the GPU, whereas if you snapshot you 
have to do a readback.

If the only thing around is the one canvas, they're probably not that 
different.  If there are other GPU ops going on, moving data to the GPU 
won't affect those as much as doing the readback, as I understand.  But 
maybe I understand wrong?

> That's another big assumption.  From what I understand, this is a
> regular occurance on mobile.

Yes, exactly.

-Boris