UI scaling issues when physical and logical screen resolutions differ on Linux

[Martin Fox]

Hi Christopher,

This may be a side-effect of using KDE. To determine the UI scale the JavaFX code consults the “scaling-factor” setting in the “org.gnome.desktop.interface” schema. You can check this on the command line:

	gsettings get org.gnome.desktop.interface scaling-factor

This should be 0 so JavaFX can compute the scale itself. If it’s greater than 0 that’s the value JavaFX will use for the UI scale.

It appears that a KDE install can set this value to 1. In my case I started with the ARM version of Ubuntu server and then installed KDE (kubuntu-desktop) and afterward the scaling-factor was 1. This doesn’t happen when installing the standard GNOME desktop.

Martin

> On Feb 13, 2024, at 2:13 AM, Christopher Schnick <crschnick at xpipe.io> wrote:
> 
> Hello,
> 
> several users of our JavaFX applications have reported that the UI scale is too small when the physical and logical screen resolutions differ on Linux. For example in this case
> 
> <Screenshot_20240125_115224(1).png>
> 
> there is an implicit scaling factor of 150% included as the monitor is a 4k display but is using a lowered resolution of 2560x1440. This is then further stretched as the OS resolution is 1920x1080, but the main problem is that the 150% factor is somehow not getting picked up and JavaFX is treating this as a 4k display, thus making everything too small. For now these users can use -Dglass.gtk.uiScale=1.5 but that is not a nice solution to this problem.
> 
> Best
> Christopher Schnick
> 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mail.openjdk.org/pipermail/openjfx-dev/attachments/20240216/98856621/attachment.htm>