You can do something like this: QPoint tray_center = mTrayIcon->geometry().center(); QRect screen_rect = qApp->screenAt(tray_center)->geometry(); QPoint screen_center = screen_rect.center(); Qt::Corner corner = Qt::TopLeftCorner; if (tray_center.x() > screen_center.x() && tray_center.y() <= screen_center.y()) corner = Qt::TopRightCorner; else if (tray_center.x() > screen_center.x() && tray_center.y() > screen_center.y()) corner = Qt::BottomRightCorner; else if (tray_center.x() <= screen_center.x() && tray_center.y() > screen_center.y()) corner = Qt::BottomLeftCorner; So yeah, screenAt will give you the screen you're on and corner will tell you which corner of the screen are you in. Then you can use qApp->screenAt(tray_center)->availableGeometry() to determine the workable area of that screen and use the corner information to place your widget. You don't need to know if it's a primary , left or right screen. The available geometry is enough for your purpose.

If I am not mistaken the relation between the physical and logical pixels is the scaling factor (usually set by the operating system). For example, Apple's Retina displays usually have a scaling of 200%. Which means that for every logical pixel there are 2 physical pixels (actually 2 in x- and y-direction each; which makes 4 in total) inside your display. You should try to change the scaling in your OS and then write a small toy program to see what physical and logical DPI you get. The physical DPI should be fixed.

Yes i did. And with that clue i figured it out! QApplication::desktop()->screenGeometry(screenIndex); works like a charm. Tyvm!

@SGaist Thank you so much, it's my first time with mobile and I'm still working it out. It worked perfectly, and also thank you for answering so quickly!

Hi, Sounds like you may have found a regression. You should take a look at the bug report system to see if it's something known. If not please consider opening a new report providing a minimal compilable example showing the behavior

oh i solved my question, int QDesktopWidget::screenNumber(const QPoint & point) const