Determine programmatically screens geometry in a multi-desktop environment with Qt

Question

I am writing a screenshotting app (a bit like puush) using Qt 4.8, and I am having troubles with multiple screens setups, especially when the main monitor (with coordinates

Answer 1

You can access each screen information inside the QDesktopWidget widget you are using and compute the overall rectangle for the snapshot.

int screens = desktop->screenCount();
QRect wholeDisplayGeometry;
for (int i = 0; i < screens; ++i) {
     QRect screenRect = desktop->screen(i)->geometry();
     wholeDisplayGeometry = wholeDisplayGeometry.united(screenRect); //union
}

Now you can take the shot using the rectangle information:

QPixmap shot = QPixmap::grabWindow (
    desktop->winId (), 
    wholeDisplayGeometry.x(), 
    wholeDisplayGeometry.y(), 
    wholeDisplayGeometry.width(), 
    wholeDisplayGeometry.height()
);