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(); }