[whatwg] getImageData/putImageData comments
ian at hixie.ch
Fri Jun 12 23:57:03 PDT 2009
On Sat, 13 Jun 2009, Robert O'Callahan wrote:
> On Sat, Jun 13, 2009 at 6:39 AM, Ian Hickson <ian at hixie.ch> wrote:
> > The long and short of this is that if we solve this problem today, the
> > solution will be abused as much as the current API, and we'll have to
> > introduce yet another solution when high-res backing stores are common. So
> > instead I'm hoping that (a) authors won't screw this up, and (b) high-res
> > backing stores will be implemented sooner rather than later. If we fail
> > with (a), which is more likely if (b) is delayed, then we'll just
> > introduce a higher-res API later, and designate this one a lost cause.
> Whether high-resolution backing stores are implemented or not is
> irrelevant as long as most authors are testing their scripts on systems
> configured with a 1:1 ratio of CSS pixels to device pixels. So in
> practice you're also relying on (c) rapid deployment of high-dpi screens
> to canvas-using Web developers. That's why I think you hope in vain.
> Altering the current API so that it always uses one image-data pixel per
> CSS pixel would not make it useless. Everything people are currently
> using it for will continue to work just fine and the visual results will
> be just as good as what people are currently seeing. It's just that
> we'll need a new API in the future to take maximum advantage of
Right, but that would be less optimal than if we could just re-use today's
API, hence the hope.
There's no practical difference as far as I can tell between hoping that
we can reuse the API, and then finding we can't, and introducing a second
API for high-res screens; and just giving up now and saying that it's a
low-res API, and then adding a second API later when we have high-res
screens. The effect is more or less the same. Given that, I think it's
worth at least trying to see if we get away with it and can in fact use
this API in high-res situations later.
Ian Hickson U+1047E )\._.,--....,'``. fL
http://ln.hixie.ch/ U+263A /, _.. \ _\ ;`._ ,.
Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
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