Or maybe I did not understand the meaning of Resolution.

This is the code I used -

SystemInformation["Devices", "ScreenInformation"]

I get 120 as my system resolution, and Full Screen Area as 1366x768 (~14" diagonal screen).

I checked with two of my colleagues who have mathematica installed. The one with a ~15.4" diagonal screen got Resolution as 96 & Full Screen Area as 1366x768. This made sense, sort of, a bigger screen is lesser dense pixel-wise for the same pixel screen area. But when I checked with another ~14" diagonal screen laptop, mathematica returned Resolution as 96 & Full Screen Area as 1366x768. This doesn't make sense, two physically equivalent screens with same pixel area but different resolutions.

So I cross-checked in these two websites - http://pediddle.net/dpi-ruler.html and http://concentriclivers.com/screen_density.html

Both my laptop and the other 14" laptop got similar dpi's of 112, and the 15" laptop returned a dpi value of about 100. I did the math and these numbers fit it just well.

So is Mathematica wrong here? Or am I barking up the wrong tree for the dpi value?

I am new here, so thanks for any help extended, in advance!


On a Windows machine you can set the display resolution in terms of DPI yourself (in the Display control panel). Whereas 96 DPi is a common setting for normal density screens, 120 DPI is useful and common for high density screens. This has effect on font size and appearance and also on thing like icons.

enter image description here

96 x 1.25 = 120.

Other options can be found in the "Set custom text size (DPI) tab".

I assume that what Mathematica is reporting is just this software setting, not the actual native dots-per-inch value of your screen.

  • $\begingroup$ How can I get the actual dots-per-inch of a screen using Mathematica then? I played with both the settings, noticed as you mentioned, that the resolution shown by mathematica changed with the "Smaller" and "Medium" settings, but the actual dots-per-inch still remains at 112 dpi $\endgroup$
    – Murali
    Oct 15 '12 at 11:10
  • $\begingroup$ @murali I don't think the OS knows about the actual number of pixels that go into an inch. The 96 and 120 dpi values are estimates for 'typical' monitors, and the OS just assumes one or the other value (or whatever you change it to in the "Set custom text size (DPI) tab". The OS only gets to know the actual number of pixels that fit on the screen but not its physical dimensions, so a DPI measure can't be determined. If you need this value, let the user enter it using, for instance, the site you refer to. Why do you think that site works the way it does? $\endgroup$ Oct 15 '12 at 13:18
  • $\begingroup$ yeah, makes sense. But I was sort of hoping for the OS to have an idea about the physical dimensions of the screen display area. That has been the only missing piece of information.. $\endgroup$
    – Murali
    Oct 16 '12 at 6:24

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