QRectF rect(0.0, 0.0, 100.0, 50.0);
QPointF point(10.0, 20.0); if (rect.contains(point)) { // do something }
QRectF oldRect(0.0, 0.0, 100.0, 50.0); QRectF newRect = oldRect.adjusted(0.0, 0.0, -10.0, -10.0);This example scales a rectangle by 10 units (both horizontally and vertically) using the `adjusted` method. The resulting QRectF object has a width of 90 and a height of 40. The package library for QRectF is Qt.