Monitor dependent DPI size with shared home

[Paul Menzel]

Dear Vinzenz,


Am 20.11.2017 um 20:16 schrieb Vinzenz Vietzke:

>> At our institute the home directory is shared over NFS, so a user can
>> log in at different systems, and get the same home directory.
>>
>> We would like to get HiDPI monitors with new systems, and face the
>> problem, that certain configuration options, like the custom DPI setting
>> for the font (Settings → Appearance → Fonts), are not monitor dependent
>> but “global”.
>>
>> So users increasing the font size on their HiDPI monitor, will have a
>> too big font, when they log in at the PC pool with old “normal” monitors.
>>
>> Does Xfce 4.12 support this use case?
> 
> no, not out of the box. But you could go with some scripting.
> 
> Place a bash script into .xinitrc or into .config/autostart/ which:
> 
> 1. detects monitor size with xpdyinfo or xrandr as mentioned here:
> https://askubuntu.com/questions/584688/how-can-i-get-the-monitor-resolution-using-the-command-line
> 
> 2. runs "xfconf-query -c xsettings -p /Xft/DPI -s <your preferred dpi>"
> depending on the previously detected resolution.

Thank you for the suggestion. I guess, we need to help our users then to 
set such things up.

Is such a missing feature considered a bug, and should I create a ticket 
in the bug tracker?

> I'd recommend you to set different themes for Gtk and window borders as
> well to avoid small UI elements.

Yes, we also changed these things. I only mentioned the DPI font size to 
keep my example simple.

The “GDK scaling environment variables” also need to be set. That should 
also be possible in the display menu. I’ll submit an issue for that too. 
Currently, we set it for all monitors (that means no mixed setups 
possible) by providing a “HiDPI Xfce session” option in GDM.

```
$ more /usr/share/xsessions/xfce4_hidpi.desktop
[Desktop Entry]
Version=1.0
Name=Xfce4 Desktop (HiDPI)
Comment=Use this session to run Xfce as your desktop environment
Exec=ck-launch-session startxfce4_hidpi
Icon=
Type=Application
$ more /usr/bin/startxfce4_hidpi
#!/bin/bash
export GDK_SCALE=2
export GDK_DPI_SCALE=-1
export XCURSOR_SIZE=48
/usr/bin/startxfce4 "$@"
```


Kind regards,

Paul