view.cpp Example File

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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.
  **
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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, SIGNAL(clicked(QPointF)), this, SLOT(keepCallout()));
      connect(series, SIGNAL(hovered(QPointF, bool)), this, SLOT(tooltip(QPointF,bool)));

      connect(series2, SIGNAL(clicked(QPointF)), this, SLOT(keepCallout()));
      connect(series2, SIGNAL(hovered(QPointF, bool)), this, SLOT(tooltip(QPointF,bool)));

      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);
           foreach (Callout *callout, m_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();
      }
  }