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I am trying to use QtCharts to plot randomly-generated data into a scatter plot in real time. I want to do this using QtCharts, and have even tried repurposing the Qt Audio Example into a solution, but have had no luck. Any advice on how to correctly do this?

eyllanesc
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MrFreeze2017
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1 Answers1

0

I changed Qt Scatterchart Example For you :

you need just to use a QTimer and QRandomGenerator.

chartview.h :

#ifndef CHARTVIEW_H
#define CHARTVIEW_H

#include <QtCharts/QChartView>

QT_CHARTS_USE_NAMESPACE

class ChartView: public QChartView
{
    Q_OBJECT

public:
    explicit ChartView(QWidget *parent = 0);

private:
    QTimer *_timer;
    int     _x = 0;
};

#endif // CHARTVIEW_H

chartview.cpp :

#include "chartview.h"
#include <QtCharts/QScatterSeries>
#include <QtCharts/QLegendMarker>
#include <QTimer>
#include <QtMath>
#include <QtCore/QRandomGenerator>

ChartView::ChartView(QWidget *parent):
    QChartView(new QChart(), parent)
{
    QScatterSeries *series0 = new QScatterSeries();

    series0->setName("scatter1");
    series0->setMarkerShape(QScatterSeries::MarkerShapeCircle);
    series0->setMarkerSize(15.0);


    QScatterSeries *series2 = new QScatterSeries();
    series2->setName("scatter2");
    series2->setMarkerShape(QScatterSeries::MarkerShapeCircle);
    series2->setMarkerSize(15.0);


    _timer = new QTimer();


connect(_timer, &QTimer::timeout, this, [series0, this]()
{
    series0->append(_x++, QRandomGenerator::global()->bounded(10));
});

_timer->start(1000);


    *series2 << QPointF(1, 5) << QPointF(4, 6) << QPointF(6, 3) << QPointF(9, 5);


    setRenderHint(QPainter::Antialiasing);
    chart()->addSeries(series0);
    chart()->addSeries(series2);

    chart()->setTitle("Simple scatterchart example");
    chart()->createDefaultAxes();
    chart()->setDropShadowEnabled(false);

    chart()->legend()->setMarkerShape(QLegend::MarkerShapeFromSeries);
}

The OutPut is :

enter image description here

Parisa.H.R
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  • Thank you very much. Say I wanted to my x-value to increase by one each time so to represent each second passing, but I wanted my y-values to still plot randomly. How would I append the series so that the x-value increases by 1 each time? – MrFreeze2017 Jul 19 '21 at 04:12
  • it's easy , I will edit it to show that. I define _x variable and append it as x value in connect slots , and then increase it by x++ ; and set 1000 ms for timer means 1 second , each second connect calls and value of _x increased. – Parisa.H.R Jul 19 '21 at 06:54