Re: [whatwg] High-density canvases

On 11 Sep 2013, at 5:32 am, Ian Hickson <> wrote:

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

Because weve 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 dont think wed ever want to change the behaviour.


> 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.

Received on Tuesday, 10 September 2013 19:46:17 UTC