On Wed, Nov 23, 2022 at 14:01 (-0500), Felix Miata wrote:
Jim composed on 2022-11-23 11:41 (UTC-0400):
Anyway, xrandr can be asked to report the EDID information for an attached screen. And that can be parsed to get information such as the (alleged) physical screen size (in mm). Knowing the number of pixels on the screen, the DPI value can be calculated.
Here is a (zsh, but may work with other shells) to get the information of the (first only?) attached screen:
Instead of all that work measuring and calculating,
It's no work, I let the computer do it. :-)
use a tool that does the work for you:
inxi -Gaz --vs
Neither inxi on Slackware64 15.0 nor Raspbian GNU/Linux 10 like the --vs option. What system are you using?
inxi 3.3.23-00 (2022-10-31) Graphics:
<snip>
Each monitor's actual dimensions and DPI are accurately reported (from EDID, if it exists), and the entire screen's /logical/ dimensions and DPI (what the software uses: s-dpi: 120) are also reported.
Thanks for that info (I'm no inxi guru). Unfortunately, inxi isn't always so informative. For example, on an RPi 4, hooked up to a Sony TV, I only get
$ inxi -Gaz Graphics: Device-1: bcm2711-vc5 driver: vc4_drm v: N/A Device-2: bcm2711-hdmi0 driver: N/A Device-3: bcm2711-hdmi1 driver: N/A Display: tty server: X.Org 1.20.4 driver: modesetting unloaded: fbdev resolution: 1920x1080~60Hz OpenGL: renderer: V3D 4.2 v: 2.1 Mesa 19.3.2
which isn't all that informative.
Cheers.
Jim