QT5 screen scale factor

In my previous post, I described the problem of having too large interface buttons, search fields, scroll bars, etc of Calibre (compiled against QT5). I found a fix of Calibre, however, it seems this problem occurs for other QT5 programs. For example, I installed AlienBob’s VLC package, version 3.0.4 on Slackware64 14.2 and noticed the same issue. So, a more general solution should be found.

I searched a bit and found this discussion in the Ubuntu forums, with this post in particular.

Well, I do not have a /etc/profile.d/gnome-qt.sh, therefore I added this line to /etc/profile.d/qt5.sh instead:

export QT_AUTO_SCREEN_SCALE_FACTOR=0

It may be a problem with my video card, therefore here’s how my card is recognised: Advanced Micro Devices, Inc. [AMD/ATI] Caicos [Radeon HD 6450/7450/8450 / R5 230 OEM].

Now VLC looks fine and the same goes for Calibre without the fix from my earlier post.