chartview.cpp Example File

scatterinteractions/chartview.cpp
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 #include "chartview.h"
 #include <QtCore/QtMath>
 #include <QtCore/QDebug>

 QT_CHARTS_USE_NAMESPACE

 ChartView::ChartView(QWidget *parent)
     : QChartView(new QChart(), parent),
       m_scatter(0),
       m_scatter2(0)
 {
     setRenderHint(QPainter::Antialiasing);

     chart()->setTitle("Click to interact with scatter points");

     m_scatter = new QScatterSeries();
     m_scatter->setName("scatter1");
     for (qreal x(0.5); x <= 4.0; x += 0.5) {
         for (qreal y(0.5); y <= 4.0; y += 0.5)
             *m_scatter << QPointF(x, y);
     }
     m_scatter2 = new QScatterSeries();
     m_scatter2->setName("scatter2");

     chart()->addSeries(m_scatter2);
     chart()->addSeries(m_scatter);
     chart()->createDefaultAxes();
     chart()->axes(Qt::Horizontal).first()->setRange(0, 4.5);
     chart()->axes(Qt::Vertical).first()->setRange(0, 4.5);

     connect(m_scatter, &QScatterSeries::clicked, this, &ChartView::handleClickedPoint);
 }

 ChartView::~ChartView()
 {
 }

 void ChartView::handleClickedPoint(const QPointF &point)
 {
     QPointF clickedPoint = point;
     // Find the closest point from series 1
     QPointF closest(INT_MAX, INT_MAX);
     qreal distance(INT_MAX);
     const auto points = m_scatter->points();
     for (const QPointF &currentPoint : points) {
         qreal currentDistance = qSqrt((currentPoint.x() - clickedPoint.x())
                                       * (currentPoint.x() - clickedPoint.x())
                                       + (currentPoint.y() - clickedPoint.y())
                                       * (currentPoint.y() - clickedPoint.y()));
         if (currentDistance < distance) {
             distance = currentDistance;
             closest = currentPoint;
         }
     }

     // Remove the closes point from series 1 and append it to series 2
     m_scatter->remove(closest);
     m_scatter2->append(closest);
 }