Qt 5.9 | Qt Charts | Scatter Interactions Example | chartview.cpp Example File

Qt 5.9.3 Reference Documentation

# chartview.cpp Example File

scatterinteractions/chartview.cpp

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      ** Contact: https://www.qt.io/licensing/
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      ** This file is part of the Qt Charts module of the Qt Toolkit.
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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()->axisX()->setRange(0, 4.5);
          chart()->axisY()->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);
      }