This is just another reason why all browsers (not just mobile) should be reporting their screen size. As in, the actual height/width. Not pixels. Pixels lie and so do browsers, actually. If I knew that the user's browser was 3 inches wide I could choose a point-based font size that's appropriate. It would also be trivially easy to scale font and image sizes up or down based on that knowledge. Especially if I'm using…
> As in, the actual height/width. Not pixels. What does the browser in an Oculus Rift report? What about the projector on my wall? Perhaps we're more interested in angular sizes, and then possibly pixel densities (again in terms of angular size) in case we need to worry about font legibility etc.
Which is how the reference pixel is defined:
> The reference pixel is the visual angle of one pixel on a device with a pixel density of 96dpi and a distance from the reader of an arm's length. For a nominal arm's length of 28 inches, the visual angle is therefore about 0.0213 degrees. For reading at arm's length, 1px thus corresponds to about 0.26 mm (1/96 inch).