Qt 5.9 | Qt Charts | Callout Example | view.cpp Example File

Qt 5.9.9 Reference Documentation

# view.cpp Example File

callout/view.cpp

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      ** 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.
      **
      ** $QT_BEGIN_LICENSE:GPL$
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      ** Alternatively, this file may be used under the terms of the GNU
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      ** the Free Software Foundation and appearing in the file LICENSE.GPL3
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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();
          }
      }