scatterinteractionswidget.cpp

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// Copyright (C) 2023 The Qt Company Ltd.

// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause

#include "scatterinteractionswidget.h"

#include <QChart>

#include <QtMath>

#include <QScatterSeries>

ScatterInteractionsWidget::ScatterInteractionsWidget(QWidget *parent)

    : ContentWidget(parent)

    m_scatter = new QScatterSeries;

    m_scatter->setName("scatter1");

    for (qreal x(0.5); x <= 4.0; x += 0.5) {

        for (qreal y(0.5); y <= 4.0; y += 0.5)

            *m_scatter << QPointF(x, y);

    m_scatter2 = new QScatterSeries;

    m_scatter2->setName("scatter2");

    auto *chart = new QChart;

    chart->setTitle("Click to interact with scatter points");

    chart->addSeries(m_scatter2);

    chart->addSeries(m_scatter);

    chart->createDefaultAxes();

    chart->axes(Qt::Horizontal).first()->setRange(0, 4.5);

    chart->axes(Qt::Vertical).first()->setRange(0, 4.5);

    connect(m_scatter, &QScatterSeries::clicked,

            this, &ScatterInteractionsWidget::handleClickedPoint);

    createDefaultChartView(chart);

void ScatterInteractionsWidget::handleClickedPoint(const QPointF &point)

    QPointF clickedPoint = point;

    // Find the closest point from series 1

    QPointF closest(INT_MAX, INT_MAX);

    qreal distance(INT_MAX);

    const auto points = m_scatter->points();

    for (const QPointF &currentPoint : points) {

        qreal currentDistance = qSqrt((currentPoint.x() - clickedPoint.x())

                                      * (currentPoint.x() - clickedPoint.x())

                                      + (currentPoint.y() - clickedPoint.y())

                                      * (currentPoint.y() - clickedPoint.y()));

        if (currentDistance < distance) {

            distance = currentDistance;

            closest = currentPoint;

    // Remove the closest point from series 1 and append it to series 2

    m_scatter->remove(closest);

    m_scatter2->append(closest);