Qt 5.7 | Qt Charts | DateTimeAxis Example | main.cpp Example File

Qt 5.7.1 Reference Documentation

# main.cpp Example File

datetimeaxis/main.cpp

      /****************************************************************************
      **
      ** 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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      ** 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 <QtWidgets/QApplication>
      #include <QtWidgets/QMainWindow>
      #include <QtCharts/QChartView>
      #include <QtCharts/QLineSeries>
      #include <QtCore/QDateTime>
      #include <QtCharts/QDateTimeAxis>
      #include <QtCore/QFile>
      #include <QtCore/QTextStream>
      #include <QtCore/QDebug>
      #include <QtCharts/QValueAxis>

      QT_CHARTS_USE_NAMESPACE

      int main(int argc, char *argv[])
      {
          QApplication a(argc, argv);
          qsrand(QTime(0, 0, 0).secsTo(QTime::currentTime()));

          QLineSeries *series = new QLineSeries();

          // data from http://www.swpc.noaa.gov/ftpdir/weekly/RecentIndices.txt
          // http://www.swpc.noaa.gov/ftpdir/weekly/README
          // http://www.weather.gov/disclaimer
          QFile sunSpots(":sun");
          if (!sunSpots.open(QIODevice::ReadOnly | QIODevice::Text)) {
              return 1;
          }

          QTextStream stream(&sunSpots);
          while (!stream.atEnd()) {
              QString line = stream.readLine();
              if (line.startsWith("#") || line.startsWith(":"))
                  continue;
              QStringList values = line.split(" ", QString::SkipEmptyParts);
              QDateTime momentInTime;
              momentInTime.setDate(QDate(values[0].toInt(), values[1].toInt() , 15));
              series->append(momentInTime.toMSecsSinceEpoch(), values[2].toDouble());
          }
          sunSpots.close();

          QChart *chart = new QChart();
          chart->addSeries(series);
          chart->legend()->hide();
          chart->setTitle("Sunspots count (by Space Weather Prediction Center)");

          QDateTimeAxis *axisX = new QDateTimeAxis;
          axisX->setTickCount(10);
          axisX->setFormat("MMM yyyy");
          axisX->setTitleText("Date");
          chart->addAxis(axisX, Qt::AlignBottom);
          series->attachAxis(axisX);

          QValueAxis *axisY = new QValueAxis;
          axisY->setLabelFormat("%i");
          axisY->setTitleText("Sunspots count");
          chart->addAxis(axisY, Qt::AlignLeft);
          series->attachAxis(axisY);

          QChartView *chartView = new QChartView(chart);
          chartView->setRenderHint(QPainter::Antialiasing);

          QMainWindow window;
          window.setCentralWidget(chartView);
          window.resize(820, 600);
          window.show();

          return a.exec();
      }