QFont and device independent font size

I wrote a casual game for Android, faced the following problem. The inscriptions, on phones with a screen of 5 "and less, look more than intended, and on tablets, look less than intended.


There are 2 types of QLable labels and those that are drawn with QPainter by the drawText method.
The basic size of the game screen is 960x600, and depending on the device being launched, it stretches or contracts.

I turned to the documentation on the QFont class.
The following is written according to the setPixelSize method (direct translation):

       .  setPointSize()  setPointSizeF(),         . 

In fact, at least for Android devices, this is not true.
And the truth is exactly the opposite: setPointSize - depends on the device, setPixelSize - does not depend on the device.

Maybe I do not correctly understand the meaning of the expression - it depends on / does not depend on the device, but using setPixelSize solved my problem.
')
Write how to cope with a similar problem on other operating systems.