chart.cpp Example File

zoomlinechart/chart.cpp
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 #include "chart.h"
 #include <QtWidgets/QGesture>
 #include <QtWidgets/QGraphicsScene>
 #include <QtWidgets/QGraphicsView>

 Chart::Chart(QGraphicsItem *parent, Qt::WindowFlags wFlags)
     : QChart(QChart::ChartTypeCartesian, parent, wFlags)
 {
     // Seems that QGraphicsView (QChartView) does not grab gestures.
     // They can only be grabbed here in the QGraphicsWidget (QChart).
     grabGesture(Qt::PanGesture);
     grabGesture(Qt::PinchGesture);
 }

 Chart::~Chart()
 {

 }

 bool Chart::sceneEvent(QEvent *event)
 {
     if (event->type() == QEvent::Gesture)
         return gestureEvent(static_cast<QGestureEvent *>(event));
     return QChart::event(event);
 }

 bool Chart::gestureEvent(QGestureEvent *event)
 {
     if (QGesture *gesture = event->gesture(Qt::PanGesture)) {
         QPanGesture *pan = static_cast<QPanGesture *>(gesture);
         QChart::scroll(-(pan->delta().x()), pan->delta().y());
     }

     if (QGesture *gesture = event->gesture(Qt::PinchGesture)) {
         QPinchGesture *pinch = static_cast<QPinchGesture *>(gesture);
         if (pinch->changeFlags() & QPinchGesture::ScaleFactorChanged)
             QChart::zoom(pinch->scaleFactor());
     }

     return true;
 }