[whatwg] High-density canvases

[Dean Jackson]

On 11 Sep 2013, at 5:32 am, Ian Hickson <ian at hixie.ch> wrote:

> On Wed, 11 Sep 2013, Dean Jackson wrote:
>> On 11 Sep 2013, at 12:14 am, Stephen White <senorblanco at chromium.org> 
>> wrote:
>>> 
>>> now that some browsers are including browser zoom (page zoom) in 
>>> window.devicePixelRatio
>> 
>> Ouch. Who is doing this and why?
> 
> Why ouch?

Because we’ve always operated under the assumption that devicePixelRatio is the mapping from CSS px to device pixels at 1:1 scale/zoom, and that it is constant for a particular display. The only change content would see is if the window is dragged to/from a high resolution screen.

There are other ways to query the page zoom.

I fear this will break existing content. I don’t think we’d ever want to change the behaviour.

Dean

> 
> Actually what I really think we should do is also change the 
> window.devicePixelRatio for pinch zoom. Combined with the suggestions for 
> canvas, that would allow (as Rik pointed out on IRC) for high-quality 
> canvas all the way zoomed in, and for cheap canvases when zoomed out.