void Widget::plotQtChart()
{
QChart* chart = ui->qtChart->chart();
if(!chart)
{
chart = new QChart();
ui->qtChart->setChart(chart);
}
QValueAxis * axisX = qobject_cast<QValueAxis *>(chart->axisX());
QValueAxis * axisY = qobject_cast<QValueAxis *>(chart->axisY());
QLineSeries* line = NULL;
if(chart->series().size()>0)
{
line = qobject_cast<QLineSeries*>(chart->series().at(0));
}
else
{
line = new QLineSeries;
}
line->setUseOpenGL(true);
chart->addSeries(line);
line->attachAxis(axisX);
line->attachAxis(axisY);
QVector<QPointF> points;
for(int i=0;i<320000;++i)
{
points.append(QPointF(i,sin(i)));
}
line->replace(points);
}
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(" ", QString::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();
}
