mainwidget.cpp Example File

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#include "mainwidget.h" #include <QtCharts/QChart> #include <QtCharts/QChartView> #include <QtWidgets/QPushButton> #include <QtWidgets/QLabel> #include <QtCore/QDebug> #include <QtCharts/QLegend> #include <QtWidgets/QFormLayout> #include <QtCharts/QLegendMarker> #include <QtCharts/QLineSeries> #include <QtCharts/QXYLegendMarker> #include <QtCore/QtMath> QT_CHARTS_USE_NAMESPACE MainWidget::MainWidget(QWidget *parent) : QWidget(parent) { // Create chart view with the chart m_chart = new QChart(); m_chartView = new QChartView(m_chart, this); // Create layout for grid and detached legend m_mainLayout = new QGridLayout(); m_mainLayout->addWidget(m_chartView, 0, 1, 3, 1); setLayout(m_mainLayout); // Add few series addSeries(); addSeries(); addSeries(); addSeries(); connectMarkers(); // Set the title and show legend m_chart->setTitle("Legendmarker example (click on legend)"); m_chart->legend()->setVisible(true); m_chart->legend()->setAlignment(Qt::AlignBottom); m_chartView->setRenderHint(QPainter::Antialiasing); } void MainWidget::addSeries() { QLineSeries *series = new QLineSeries(); m_series.append(series); series->setName(QString("line " + QString::number(m_series.count()))); // Make some sine wave for data QList<QPointF> data; int offset = m_chart->series().count(); for (int i = 0; i < 360; i++) { qreal x = offset * 20 + i; data.append(QPointF(i, qSin(qDegreesToRadians(x)))); } series->append(data); m_chart->addSeries(series); if (m_series.count() == 1) m_chart->createDefaultAxes(); } void MainWidget::removeSeries() { // Remove last series from chart if (m_series.count() > 0) { QLineSeries *series = m_series.last(); m_chart->removeSeries(series); m_series.removeLast(); delete series; } } void MainWidget::connectMarkers() { // Connect all markers to handler const auto markers = m_chart->legend()->markers(); for (QLegendMarker *marker : markers) { // Disconnect possible existing connection to avoid multiple connections QObject::disconnect(marker, &QLegendMarker::clicked, this, &MainWidget::handleMarkerClicked); QObject::connect(marker, &QLegendMarker::clicked, this, &MainWidget::handleMarkerClicked); } } void MainWidget::disconnectMarkers() { const auto markers = m_chart->legend()->markers(); for (QLegendMarker *marker : markers) { QObject::disconnect(marker, &QLegendMarker::clicked, this, &MainWidget::handleMarkerClicked); } } void MainWidget::handleMarkerClicked() { QLegendMarker* marker = qobject_cast<QLegendMarker*> (sender()); Q_ASSERT(marker); switch (marker->type()) { case QLegendMarker::LegendMarkerTypeXY: { // Toggle visibility of series marker->series()->setVisible(!marker->series()->isVisible()); // Turn legend marker back to visible, since hiding series also hides the marker // and we don't want it to happen now. marker->setVisible(true); // Dim the marker, if series is not visible qreal alpha = 1.0; if (!marker->series()->isVisible()) alpha = 0.5; QColor color; QBrush brush = marker->labelBrush(); color = brush.color(); color.setAlphaF(alpha); brush.setColor(color); marker->setLabelBrush(brush); brush = marker->brush(); color = brush.color(); color.setAlphaF(alpha); brush.setColor(color); marker->setBrush(brush); QPen pen = marker->pen(); color = pen.color(); color.setAlphaF(alpha); pen.setColor(color); marker->setPen(pen); break; } default: { qDebug() << "Unknown marker type"; break; } } }

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