Qt Creator and all application using Qt 5.6+: Fonts too small on 4K monitor

[Tetractys]

Hi!
I have:

• 4K monitor at 3840x2160 60Hz.
• NVIDIA GTX 980 - (drivers ver. 367.27) on Ubuntu-MATE 16.04 - Cinnamon DE ver 3.0.5
• Qt Creator 4.0.1:
  Based on Qt 5.6.1 (GCC 4.9.1 20140922 (Red Hat 4.9.1-10), 64 bit)
  Built on Jun 6 2016 17:13:49
  From revision 6863acfe91

QTCreator and any other QT based application i have tested, have fonts visualization of content and interface far too small.
Applications i'm using and i tested are: qBittorrent TeamSpeak3 and SMPlayer (but this one has HDPI switch built in that, when switched on, distorts horribly the geometry of interface itself).

For QT4 there were qtconfig-qt4. Any tool like this for QT5 system-wide configuration?
There is a method to multiply or configure the size of fonts?
Thanks in advance.

[SGaist]

Hi and welcome to devnet,

IIRC, Qt Creator 4.0.2 has just been released, can you check against that version again ?

[Tetractys]

@SGaist i updated to 4.0.2 version.
It worked as intended.
Even in all applications, that use QT libraries, fonts are aligned to the default size of the desktop environment.
So, solved! thanks a lot!

[SGaist]

You're welcome !

Since you have it working now, please mark the thread as solved using the "Topic Tool" button so that other forum users may know a solution has been found :)

[Tetractys]

@SGaist I did a fresh install of qt-unified-linux-x64-2.0.3-1-online.run on a new Ubuntu-MATE 16.04 - Cinnamon DE ver 3.0.5.
QtCreator is in version 4.0.2 but the problem of small fonts on a 4K display (3840x2160) sadly reappeared.
I tried with the system global variables but seems problematic to manage fonts (i mean making them readable) for any qt5 applications.
Any clue? global variables seems not working at all.

Having a 4K monitor and avoid to use it at max resolution is a non sense :)
Thanks in advance

[KeithS]

Have you looked at: https://blog.qt.io/blog/2016/01/26/high-dpi-support-in-qt-5-6/ ?

[Tetractys]

@KeithS thanks for the link.
I tried to set the global vars and all explained in the link but nothing equilibrated and visually acceptable.
I think the problem is related to the Cinnamon DE (3.0.5). Installing MATE 1.14.1, every QT* related applications follow perfectly the setup of fonts and interface aspect integrating perfectly all apps (QTCreator included) avoiding any use and forcing of global variables!
So, i strongly suggest to everyone had same type of interface problems on Linux to try MATE 1.14.1 Desktop Environment (fork of the well known Gnome 2). See: http://mate-desktop.org/.
Thanks a lot for everything!