01 bool PinchWidget::event(QEvent *event)
02 {
03   if(event‑>type() == QEvent::Gesture)
04    return gestureEvent(static_cast<QGestureEvent*>(event));
05   return QWidget::event(event);
06 }
07
08 bool PinchWidget::gestureEvent(QGestureEvent *event)
09 {
10    if(QGesture *pinch = event->gesture(Qt::PinchGesture))
11     {
12       pinchGesture(static_cast<QPinchGesture*>(pinch));
13       return true;
14     }
15    return false;
16 }
17
18 void PinchWidget::pinchGesture(QPinchGesture *gesture)
19 {
20   QPinchGesture::ChangeFlags flags = gesture->changeFlags();
21   if(flags & QPinchGesture::RotationAngleChanged)
22    {
23      qreal value = gesture->rotationAngle();
24      qreal lastValue = gesture‑>lastRotationAngle();
25      rotationAngle += value - lastValue;
26    }
27   if(flags & QPinchGesture::ScaleFactorChanged)
28    {
29      currentScaleFactor = gesture->scaleFactor();
30    }
31   if(gesture->state() == Qt::GestureFinished)
32    {
33      scaleFactor *= currentScaleFactor;
34      currentScaleFactor = 1;
35    }
36 update();
37 }