qt-everywhere-src-5.14.1/qtcharts/examples/charts/dynamicspline/chart.cpp

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** This file is part of the Qt Charts module of the Qt Toolkit.
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#include "chart.h"
#include <QtCharts/QAbstractAxis>
#include <QtCharts/QSplineSeries>
#include <QtCharts/QValueAxis>
#include <QtCore/QRandomGenerator>
#include <QtCore/QDebug>

Chart::Chart(QGraphicsItem *parent, Qt::WindowFlags wFlags):
    QChart(QChart::ChartTypeCartesian, parent, wFlags),
    m_series(0),
    m_axisX(new QValueAxis()),
    m_axisY(new QValueAxis()),
    m_step(0),
    m_x(5),
    m_y(1)
{
    QObject::connect(&m_timer, &QTimer::timeout, this, &Chart::handleTimeout);
    m_timer.setInterval(1000);

    m_series = new QSplineSeries(this);
    QPen green(Qt::red);
    green.setWidth(3);
    m_series->setPen(green);
    m_series->append(m_x, m_y);

    addSeries(m_series);

    addAxis(m_axisX,Qt::AlignBottom);
    addAxis(m_axisY,Qt::AlignLeft);
    m_series->attachAxis(m_axisX);
    m_series->attachAxis(m_axisY);
    m_axisX->setTickCount(5);
    m_axisX->setRange(0, 10);
    m_axisY->setRange(-5, 10);

    m_timer.start();
}

Chart::~Chart()
{

}

void Chart::handleTimeout()
{
    qreal x = plotArea().width() / m_axisX->tickCount();
    qreal y = (m_axisX->max() - m_axisX->min()) / m_axisX->tickCount();
    m_x += y;
    m_y = QRandomGenerator::global()->bounded(5) - 2.5;
    m_series->append(m_x, m_y);
    scroll(x, 0);
    if (m_x == 100)
        m_timer.stop();
}