Solution for Qt5 on Raspberry Pi 3 errors: Unable to query physical screen size.

[beranudo]

Hi

This is a solution to fix the problem on Raspberry Pi 3 with Qt 5.8

1. open the bashrc: $sudo nano ~/.bashrc
2. in the file add:
   export QT_QPA_EGLFS_PHYSICAL_WIDTH="230mm"
   export QT_QPA_EGLFS_PHYSICAL_HEIGHT="180mm"
   tip: you can try with different size, in my case I've got a display of 7" but I configure with 11.6" and looks great, the size you can check in: https://en.wikipedia.org/wiki/Display_size
3. save the file
4. $sudo source ~/.bashrc

In Qt Creator ever show the error when compiling is normal, but when you run your application from console the error's gone, other tool help the application, look better use qt5ct help a lot.