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// Copyright (C) 2023 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
#include "legendmarkerswidget.h"
#include <QChart>
#include <QChartView>
#include <QGraphicsLayout>
#include <QGridLayout>
#include <QLegend>
#include <QLegendMarker>
#include <QLineSeries>
#include <QtMath>
#include <QXYLegendMarker>
LegendMarkersWidget::LegendMarkersWidget(QWidget *parent)
: ContentWidget(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("Legend Markers (Click on legend to interact)");
m_chart->legend()->setVisible(true);
m_chart->legend()->setAlignment(Qt::AlignBottom);
m_chartView->setRenderHint(QPainter::Antialiasing);
m_chart->layout()->setContentsMargins(0, 0, 0, 0);
}
void LegendMarkersWidget::addSeries()
{
auto 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 LegendMarkersWidget::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 LegendMarkersWidget::connectMarkers()
{
//![1]
// 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, &LegendMarkersWidget::handleMarkerClicked);
QObject::connect(marker, &QLegendMarker::clicked,
this, &LegendMarkersWidget::handleMarkerClicked);
}
//![1]
}
void LegendMarkersWidget::disconnectMarkers()
{
//![2]
const auto markers = m_chart->legend()->markers();
for (QLegendMarker *marker : markers) {
QObject::disconnect(marker, &QLegendMarker::clicked,
this, &LegendMarkersWidget::handleMarkerClicked);
}
//![2]
}
void LegendMarkersWidget::handleMarkerClicked()
{
//![3]
auto marker = qobject_cast<QLegendMarker *>(sender());
Q_ASSERT(marker);
//![3]
//![4]
switch (marker->type())
//![4]
{
case QLegendMarker::LegendMarkerTypeXY:
{
//![5]
// 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);
//![5]
//![6]
// 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);
//![6]
break;
}
default:
{
qDebug("Unknown marker type");
break;
}
}
}