[whatwg] Canvas size and double buffering.
bzbarsky at MIT.EDU
Wed Feb 3 07:59:58 PST 2010
On 2/3/10 9:05 AM, Tim Hutt wrote:
> 1. You can only set the size exactly in pixels. It is very hard to get
> a resizable canvas that fills the page. You *can* set the size in CSS,
> but it doesn't work very well (e.g. using left,right-margin: auto; to
> centre the canvas doesn't work. Also it scales the canvas rather than
> resizes it.
That's right, because resizing the canvas (as in, changing the number of
pixels in the backing store) involves clearing it at the moment. Your
proposal would mean that if the user changes the window size your canvas
will immediately get cleared. Is that what you're after? If not, how
do you envision the backing-store resize being performed?
> 2. There doesn't appear to be any kind of double buffering capability.
> This is pretty critical for animations where you might need to clear
> the canvas and then draw stuff. You currently get flickering if you
You do? Under what circumstances? At least in Gecko, run-to-completion
means that while you script is running the canvas won't be painted.
What UAs are you seeing flicker in, and under what circumstances?
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