qt-everywhere-src-5.15.1/qtcharts/examples/charts/datetimeaxis/main.cpp

/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
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** This file is part of the Qt Charts module of the Qt Toolkit.
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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);

    //![1]
    QLineSeries *series = new QLineSeries();
    //![1]

    //![2]
    // 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(QLatin1Char(' '), Qt::SkipEmptyParts);
        QDateTime momentInTime;
        momentInTime.setDate(QDate(values[0].toInt(), values[1].toInt() , 15));
        series->append(momentInTime.toMSecsSinceEpoch(), values[2].toDouble());
    }
    sunSpots.close();
    //![2]

    //![3]
    QChart *chart = new QChart();
    chart->addSeries(series);
    chart->legend()->hide();
    chart->setTitle("Sunspots count (by Space Weather Prediction Center)");
    //![3]

    //![4]
    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);
    //![4]

    //![5]
    QChartView *chartView = new QChartView(chart);
    chartView->setRenderHint(QPainter::Antialiasing);
    //![5]

    //![6]
    QMainWindow window;
    window.setCentralWidget(chartView);
    window.resize(820, 600);
    window.show();
    //![6]

    return a.exec();
}