[whatwg] Processing the zoom level - MS extensions to window.screen
Ian Hickson
ian at hixie.ch
Thu May 12 21:29:05 PDT 2011
On Fri, 13 May 2011, Glenn Maynard wrote:
> On Thu, May 12, 2011 at 11:34 PM, Ian Hickson <ian at hixie.ch> wrote:
> >
> > No, ImageData exposes the underlying data, not the data in CSS pixels.
>
> I know. That's what I was responding to: having different backing store
> dimensions and dimensions exposed by ImageData doesn't make sense.
>
> If you mean that getImageData might return data of different dimensions
> than the canvas coordinate space (which I see the spec allows), that
> sounds like it would cause major interop problems if anyone actually did
> that. It's very unobvious and I'd expect most people to miss it.
It's pretty much the entire point of that API. That's why it has separate
height/width information than the canvas. It has to be that way because
there's no guarantee that CSS pixels will map to device pixels -- and
that's not theoretical, there are shipping devices with high-density
screens already (e.g. the iPhone).
> Anyway, this doesn't help this case in general anyway because the
> full-screen zoom level can change at any time.
Sure, but there's not much that can be done for that case.
--
Ian Hickson U+1047E )\._.,--....,'``. fL
http://ln.hixie.ch/ U+263A /, _.. \ _\ ;`._ ,.
Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
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