chartview.cpp Example File | Qt Charts 5.12.9

- Qt 5.12
- Qt Charts
- Zoom Line Example
- chartview.cpp Example File
- Qt Charts | Commercial or GPLv3

# chartview.cpp Example File

zoomlinechart/chartview.cpp

     /****************************************************************************
     **
     ** Copyright (C) 2016 The Qt Company Ltd.
     ** Contact: https://www.qt.io/licensing/
     **
     ** This file is part of the Qt Charts module of the Qt Toolkit.
     **
     ** $QT_BEGIN_LICENSE:GPL$
     ** Commercial License Usage
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     ** Alternatively, this file may be used under the terms of the GNU
     ** General Public License version 3 or (at your option) any later version
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     ** the Free Software Foundation and appearing in the file LICENSE.GPL3
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     #include "chartview.h"
     #include <QtGui/QMouseEvent>

     ChartView::ChartView(QChart *chart, QWidget *parent) :
         QChartView(chart, parent),
         m_isTouching(false)
     {
         setRubberBand(QChartView::RectangleRubberBand);
     }

     bool ChartView::viewportEvent(QEvent *event)
     {
         if (event->type() == QEvent::TouchBegin) {
             // By default touch events are converted to mouse events. So
             // after this event we will get a mouse event also but we want
             // to handle touch events as gestures only. So we need this safeguard
             // to block mouse events that are actually generated from touch.
             m_isTouching = true;

             // Turn off animations when handling gestures they
             // will only slow us down.
             chart()->setAnimationOptions(QChart::NoAnimation);
         }
         return QChartView::viewportEvent(event);
     }

     void ChartView::mousePressEvent(QMouseEvent *event)
     {
         if (m_isTouching)
             return;
         QChartView::mousePressEvent(event);
     }

     void ChartView::mouseMoveEvent(QMouseEvent *event)
     {
         if (m_isTouching)
             return;
         QChartView::mouseMoveEvent(event);
     }

     void ChartView::mouseReleaseEvent(QMouseEvent *event)
     {
         if (m_isTouching)
             m_isTouching = false;

         // Because we disabled animations when touch event was detected
         // we must put them back on.
         chart()->setAnimationOptions(QChart::SeriesAnimations);

         QChartView::mouseReleaseEvent(event);
     }

     void ChartView::keyPressEvent(QKeyEvent *event)
     {
         switch (event->key()) {
         case Qt::Key_Plus:
             chart()->zoomIn();
             break;
         case Qt::Key_Minus:
             chart()->zoomOut();
             break;
         case Qt::Key_Left:
             chart()->scroll(-10, 0);
             break;
         case Qt::Key_Right:
             chart()->scroll(10, 0);
             break;
         case Qt::Key_Up:
             chart()->scroll(0, 10);
             break;
         case Qt::Key_Down:
             chart()->scroll(0, -10);
             break;
         default:
             QGraphicsView::keyPressEvent(event);
             break;
         }
     }