Re: Behavior of device-pixel-ratio under zoom

On 14 November 2012 06:42, James Robinson <> wrote:

> That doesn't follow for me - devicePixelRatio is a physical property of the
> display which unless your laptop is a lot cooler than mine doesn't change
> when you press Ctrl-+.

Not true. devicePixelRatio is a relationship between the physical
display and the software-controlled size of a CSS pixel. Altering
either the display or the software will change the ratio. In this
case, the display is fixed, but the number of CSS pixels within the
viewport is decreasing as you zoom in/rescale upwards.

Basically, when you zoom in, do you add scrollbars for the parts of
the viewport that no longer fit in the window? (devicePixelRatio
should not change) Or do you re-layout the content to fit within the
smaller viewport, as measured in CSS pixels? (devicePixelRatio should
have increased)


Received on Wednesday, 14 November 2012 10:05:07 UTC