view.cpp Example File

callout/view.cpp
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 #include "view.h"
 #include <QtGui/QResizeEvent>
 #include <QtWidgets/QGraphicsScene>
 #include <QtCharts/QChart>
 #include <QtCharts/QLineSeries>
 #include <QtCharts/QSplineSeries>
 #include <QtWidgets/QGraphicsTextItem>
 #include "callout.h"
 #include <QtGui/QMouseEvent>

 View::View(QWidget *parent)
     : QGraphicsView(new QGraphicsScene, parent),
       m_coordX(0),
       m_coordY(0),
       m_chart(0),
       m_tooltip(0)
 {
     setDragMode(QGraphicsView::NoDrag);
     setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
     setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);

     // chart
     m_chart = new QChart;
     m_chart->setMinimumSize(640, 480);
     m_chart->setTitle("Hover the line to show callout. Click the line to make it stay");
     m_chart->legend()->hide();
     QLineSeries *series = new QLineSeries;
     series->append(1, 3);
     series->append(4, 5);
     series->append(5, 4.5);
     series->append(7, 1);
     series->append(11, 2);
     m_chart->addSeries(series);

     QSplineSeries *series2 = new QSplineSeries;
     series2->append(1.6, 1.4);
     series2->append(2.4, 3.5);
     series2->append(3.7, 2.5);
     series2->append(7, 4);
     series2->append(10, 2);
     m_chart->addSeries(series2);

     m_chart->createDefaultAxes();
     m_chart->setAcceptHoverEvents(true);

     setRenderHint(QPainter::Antialiasing);
     scene()->addItem(m_chart);

     m_coordX = new QGraphicsSimpleTextItem(m_chart);
     m_coordX->setPos(m_chart->size().width()/2 - 50, m_chart->size().height());
     m_coordX->setText("X: ");
     m_coordY = new QGraphicsSimpleTextItem(m_chart);
     m_coordY->setPos(m_chart->size().width()/2 + 50, m_chart->size().height());
     m_coordY->setText("Y: ");

     connect(series, &QLineSeries::clicked, this, &View::keepCallout);
     connect(series, &QLineSeries::hovered, this, &View::tooltip);

     connect(series2, &QSplineSeries::clicked, this, &View::keepCallout);
     connect(series2, &QSplineSeries::hovered, this, &View::tooltip);

     this->setMouseTracking(true);
 }

 void View::resizeEvent(QResizeEvent *event)
 {
     if (scene()) {
         scene()->setSceneRect(QRect(QPoint(0, 0), event->size()));
          m_chart->resize(event->size());
          m_coordX->setPos(m_chart->size().width()/2 - 50, m_chart->size().height() - 20);
          m_coordY->setPos(m_chart->size().width()/2 + 50, m_chart->size().height() - 20);
          const auto callouts = m_callouts;
          for (Callout *callout : callouts)
              callout->updateGeometry();
     }
     QGraphicsView::resizeEvent(event);
 }

 void View::mouseMoveEvent(QMouseEvent *event)
 {
     m_coordX->setText(QString("X: %1").arg(m_chart->mapToValue(event->pos()).x()));
     m_coordY->setText(QString("Y: %1").arg(m_chart->mapToValue(event->pos()).y()));
     QGraphicsView::mouseMoveEvent(event);
 }

 void View::keepCallout()
 {
     m_callouts.append(m_tooltip);
     m_tooltip = new Callout(m_chart);
 }

 void View::tooltip(QPointF point, bool state)
 {
     if (m_tooltip == 0)
         m_tooltip = new Callout(m_chart);

     if (state) {
         m_tooltip->setText(QString("X: %1 \nY: %2 ").arg(point.x()).arg(point.y()));
         m_tooltip->setAnchor(point);
         m_tooltip->setZValue(11);
         m_tooltip->updateGeometry();
         m_tooltip->show();
     } else {
         m_tooltip->hide();
     }
 }