inform QWidget that the screen dimensions changed

[wysota]

repaint and paintEvent are completely unrelated to the problem. They have nothing to do with dimensions of your window.

[Dzha]

OK. If the window receives showFullScreen() and it is in full screen it does nothing. It does not check that the screen has been changed. if it is sent resize(0,0) and then showFullScreen() then it occupies the full screen with new width and height.
The code is trivial. Hardware changed in the background, but the changes are not propagated. Do I need to inform some Qt class that the sceen has been transformed? If yes then how?

There are two methods in QScreen: isTransformed() and transformOrientation(). Both overwritten by my driver and return true/rotation corresponding the situation. No avail. I did a search through Qt and could see that those functions don't do much themselves, probably orientated on the transformation derived class functionality.

@wysota: appreciate your answers, thanks.

[wysota]

OK. If the window receives showFullScreen() and it is in full screen it does nothing. It does not check that the screen has been changed.

The window does not check anything. It's your (or the window manager's) duty to know the screen size has changed.

The code is trivial. Hardware changed in the background, but the changes are not proagated.

Propagated where?

[Dzha]

The window does not check anything. It's your (or the window manager's) duty to know the screen size has changed.

OK. Is there a mechanism for informing the windows manager that the screen is changed?

[wysota]

You can start by reading what a window manager is.

[Dzha]

Well, all I was able to find while reading the window manager documentation was related to resizing the window, which I want to avoid.
I can not see any method of not leaving the full screen mode (thus avoiding additional repaint) that is described in Qt doc.

If you are aware of it, please tell me.

[wysota]

Well, all I was able to find while reading the window manager documentation

Which window manager documentation was that?

[Dzha]

QWS, Qt for Embedded Linux.

[wysota]

Are you using QWS?

[Dzha]

Yes, my main app acts as a QWS server. loads a screen plugin and uses it.

[wysota]

If your application is full screen, what do you need QWS for?

[Dzha]

QWS also handles dialogs, input, etc.
My main window is an instance of QMainWindow .

[wysota]

So how do you implement screen geometry change?