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);
}
int main(int argc, char *argv[]) {
QApplication a(argc, argv);
QWidget ui;
QVBoxLayout layout(&ui);
QChartView view1, view2;
QLabel status;
layout.addWidget(&view1);
layout.addWidget(&view2);
layout.addWidget(&status);
layout.setMargin(4);
QLineSeries series;
series.replace(data());
auto *chart = view1.chart();
chart->addSeries(&series);
view1.setRubberBand(QChartView::RectangleRubberBand);
QLineSeries subSeries;
subSeries.setPointsVisible(true);
auto *subChart = view2.chart();
subChart->addSeries(&subSeries);
for (auto *chart : {view1.chart(), view2.chart()}) {
chart->legend()->hide();
chart->createDefaultAxes();
chart->layout()->setContentsMargins(0, 0, 0, 0);
}
auto update = [&] {
auto rect = seriesRect(chart, &series);
auto const points = pointsInRect(&series, rect);
status.setText(QStringLiteral("Visible Range: (%1,%2)-(%3,%4)")
.arg(rect.left())
.arg(rect.top())
.arg(rect.right())
.arg(rect.bottom()));
subSeries.replace(points);
subChart->axisX(&subSeries)->setRange(rect.left(), rect.right());
subChart->axisY(&subSeries)->setRange(rect.top(), rect.bottom());
};
QObject::connect(chart, &QChart::plotAreaChanged, update);
ui.setMinimumSize(400, 400);
ui.show();
return a.exec();
}
