Qt 5.7 | Qt Charts | OpenGL Accelerated Series Example | main.cpp Example File

Qt 5.7.1 Reference Documentation

# main.cpp Example File

openglseries/main.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.
      **
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      #include "datasource.h"
      #include <QtWidgets/QApplication>
      #include <QtWidgets/QMainWindow>
      #include <QtCharts/QChartView>
      #include <QtCharts/QLineSeries>
      #include <QtCharts/QScatterSeries>
      #include <QtCharts/QValueAxis>
      #include <QtCharts/QLogValueAxis>
      #include <QtWidgets/QLabel>

      // Uncomment to use logarithmic axes instead of regular value axes
      //#define USE_LOG_AXIS

      // Uncomment to use regular series instead of OpenGL accelerated series
      //#define DONT_USE_GL_SERIES

      // Uncomment to add a simple regular series (thick line) and a matching OpenGL series (thinner line)
      // to verify the series have same visible geometry.
      //#define ADD_SIMPLE_SERIES

      QT_CHARTS_USE_NAMESPACE

      int main(int argc, char *argv[])
      {
          QApplication a(argc, argv);
          QStringList colors;
          colors << "red" << "blue" << "green" << "black";

          QChart *chart = new QChart();
          chart->legend()->hide();

      #ifdef USE_LOG_AXIS
          QLogValueAxis *axisX = new QLogValueAxis;
          QLogValueAxis *axisY = new QLogValueAxis;
      #else
          QValueAxis *axisX = new QValueAxis;
          QValueAxis *axisY = new QValueAxis;
      #endif

          chart->addAxis(axisX, Qt::AlignBottom);
          chart->addAxis(axisY, Qt::AlignLeft);

          const int seriesCount = 10;
      #ifdef DONT_USE_GL_SERIES
          const int pointCount = 100;
          chart->setTitle("Unaccelerated Series");
      #else
          const int pointCount = 10000;
          chart->setTitle("OpenGL Accelerated Series");
      #endif

          QList<QXYSeries *> seriesList;
          for (int i = 0; i < seriesCount; i++) {
              QXYSeries *series = 0;
              int colorIndex = i % colors.size();
              if (i % 2) {
                  series = new QScatterSeries;
                  QScatterSeries *scatter = static_cast<QScatterSeries *>(series);
                  scatter->setColor(QColor(colors.at(colorIndex)));
                  scatter->setMarkerSize(qreal(colorIndex + 2) / 2.0);
                  // Scatter pen doesn't have affect in OpenGL drawing, but if you disable OpenGL drawing
                  // this makes the marker border visible and gives comparable marker size to OpenGL
                  // scatter points.
                  scatter->setPen(QPen("black"));
              } else {
                  series = new QLineSeries;
                  series->setPen(QPen(QBrush(QColor(colors.at(colorIndex))),
                                      qreal(colorIndex + 2) / 2.0));
              }
              seriesList.append(series);
      #ifdef DONT_USE_GL_SERIES
              series->setUseOpenGL(false);
      #else
              series->setUseOpenGL(true);
      #endif
              chart->addSeries(series);
              series->attachAxis(axisX);
              series->attachAxis(axisY);
          }

          if (axisX->type() == QAbstractAxis::AxisTypeLogValue)
              axisX->setRange(0.1, 20.0);
          else
              axisX->setRange(0, 20.0);

          if (axisY->type() == QAbstractAxis::AxisTypeLogValue)
              axisY->setRange(0.1, 10.0);
          else
              axisY->setRange(0, 10.0);

      #ifdef ADD_SIMPLE_SERIES
          QLineSeries *simpleRasterSeries = new QLineSeries;
          *simpleRasterSeries << QPointF(0.001, 0.001)
                       << QPointF(2.5, 8.0)
                       << QPointF(5.0, 4.0)
                       << QPointF(7.5, 9.0)
                       << QPointF(10.0, 0.001)
                       << QPointF(12.5, 2.0)
                       << QPointF(15.0, 1.0)
                       << QPointF(17.5, 6.0)
                       << QPointF(20.0, 10.0);
          simpleRasterSeries->setUseOpenGL(false);
          simpleRasterSeries->setPen(QPen(QBrush("magenta"), 8));
          chart->addSeries(simpleRasterSeries);
          simpleRasterSeries->attachAxis(axisX);
          simpleRasterSeries->attachAxis(axisY);

          QLineSeries *simpleGLSeries = new QLineSeries;
          simpleGLSeries->setUseOpenGL(true);
          simpleGLSeries->setPen(QPen(QBrush("black"), 2));
          simpleGLSeries->replace(simpleRasterSeries->points());
          chart->addSeries(simpleGLSeries);
          simpleGLSeries->attachAxis(axisX);
          simpleGLSeries->attachAxis(axisY);
      #endif

          QChartView *chartView = new QChartView(chart);

          QMainWindow window;
          window.setCentralWidget(chartView);
          window.resize(600, 400);
          window.show();

          DataSource dataSource;
          dataSource.generateData(seriesCount, 10, pointCount);

          QLabel *fpsLabel = new QLabel(&window);
          QLabel *countLabel = new QLabel(&window);
          QString countText = QStringLiteral("Total point count: %1");
          countLabel->setText(countText.arg(pointCount * seriesCount));
          countLabel->adjustSize();
          fpsLabel->move(10, 2);
          fpsLabel->adjustSize();
          fpsLabel->raise();
          fpsLabel->show();
          countLabel->move(10, fpsLabel->height());
          fpsLabel->raise();
          countLabel->show();

          // We can get more than one changed event per frame, so do async update.
          // This also allows the application to be responsive.
          QObject::connect(chart->scene(), &QGraphicsScene::changed,
                           &dataSource, &DataSource::handleSceneChanged);

          dataSource.startUpdates(seriesList, fpsLabel);

          return a.exec();
      }