I have made a clean installation of Kubuntu 16.04 and played around with the font sizes and other settings (such as the fonts DPI, but I tried resetting it...) to make it more to my liking and everything works fine, except for Viber; It is huge! It takes up pretty much the whole screen and cannot be resized to a smaller window (as the interface itself appears enormous, the letters, everything). Any other program I've used is completely normal...
Just updated to lastet Viber version and it became huge.
The reason is that 1920x1080 px on 13" screen has dpi of 166, what I have set in my xfce settings. A lot of apps powered with electron or other custom magic treat dpi over 140 as "retina" and double rendering size.
Viber settings screen cannot go UI scaling under 100%, so you can do it manually.
New solution (works for Viber >= v7.0)
Try running Viber from the terminal by specifying the
QT_SCALE_FACTOR as follows:
As a permanent solution, ensure the following line is in place in the Viber starter shortcut file (.desktop):
Exec=env QT_SCALE_FACTOR=0.6 /opt/viber/Viber
The Viber .desktop file is usually located at
/usr/share/applications/viber.desktop. A locally editable copy can be placed in
Old solution (works for Viber < v7.0)
sqlitebrowser from official repo, use it to open
Go to table
CommonSettings and modify
ScalingRatio to something under 1.0, I used 0.6.
From Qt documentation:
QT_AUTO_SCREEN_SCALE_FACTOR [boolean]enables automatic scaling, based on the pixel density of the monitor. This will not change the size of point sized fonts, since point is a physical unit of measure. Multiple screens may get different scale factors.
So setting this to false (zero) will not always solve the scaling problem. I had to change
QT_SCALE_FACTOR=0 to display Viber window normally:
env QT_SCALE_FACTOR=0 QT_AUTO_SCREEN_SCALE_FACTOR=0 /opt/viber/Viber