QT_FONT_DPI and hidpi on Mac on Qt 6: ???

Hi,

in Qt 5 I was using QT_FONT_DPI=96 on all platforms to ensure that my software looks pixel-perfect on Windows, macOS and Linux. This is what works and makes both my users and designers happy.

In Qt5 it means that the app renders the same on macOS than on Windows and Linux, if a computer is plugged in to the same monitor.

Here is the look with Qt 5 (and QT_FONT_DPI=96) on macOS (this is where my issues happen as Windows and Linux are generally configured for 96 DPI...):

In Qt 6 apparently this does not work:

• The pixmaps are all scaled in a very horrible way, the ratios aren't respected anymore (e.g. the text on the left pane does not fit its widget anymore), etc... :

And if I show two OpenGL widgets (embedded with createWindowContainer), everything... kinda explodes ; things seem to revert to their "normal" size but the whole rendering becomes garbled like if it was trying to render both sizes: