Detect screen DPI change
How can I detect screen's DPI change?
Since I have a window(derived from QWidget) which may switch between two monitors and dynamically update according to screen DPI, it seems that I can only listen to screenChanged(QScreen*) signal. It works fine when I drag the window between monitors.
But it doesn't work when I opened app in another monitor and switches menu bar between two monitors(through System Preference -> Displays -> Arrangement in mac). It seems that the signal is not emitted in that situation.
Which signal should I listen to? Is there a better way?