Different resolution values returned by qGuiApp->primaryScreen().size() on different Graphic Environments (XFCE vs GNOME)

[poor_robert]

Hello Qt Friends,

I'm working on GUI application and I've tested on different Graphic Environments. I have noticed that when I run it on XFCE my application gets wrong screen size from:
https://doc.qt.io/qt-5/qguiapplication.html#primaryScreen-prop

I have multiple Graphic Environments. I use Ubuntu 20
There is only 1 screen that has 1920 x 1080 resolution in settings. Also xrand command returns the same resolution.
In my code I use:

qGuiApp->primaryScreen().size()

On Gnome3 and Plasma it returns proper value i.e. 1920 x 1080.
However, on XCFE (and LXDE) this command returns: 960 x 540

What's also strange when I run Plasma and then switch to XFCE it works fine. But after reseting PC and opening XFCE it returns wrong values...

Do you have idea what is missing?

[SGaist]

Hi,

That rather looks like an XFCE issue. Did you check the settings of that desktop environment ?

[poor_robert]

@SGaist Hello :)
Yes, and the Screen resolution is set to 1920 x 1080. Also xrandr returns the same value...

[SGaist]

Is there some "magnifying" settings ?
The factor 2 you have is troubling.