How to reset the time on x-axis of a graph?

[halima]

@VRonin I have the same problem, I'm trying to use QElapsedTimer with QChart, can you help me to do that please. This is my code :

classe.cpp

void MaClasse::updateChart(){
     ElapsedTimer .start(); //global variable
     chart_1->chart()->axes(Qt::Horizontal).back()->setMin(ElapsedTimer .elapsed());
    chart_1->chart()->axes(Qt::Horizontal).back()->setMax(ElapsedTimer .elapsed()+10);
 chart_1->series()[0].serie->replace(buffer_0);
 QApplication::processEvents();
}

[VRonin]

What is not working?

[halima]

@vronin My code note working

[jsulm]

@halima said in How to reset the time on x-axis of a graph?:

My code note working

That's clear.
What EXACTLY is not working?

[halima]

@jsulm The max of XAxis is always 09:33:18 it's not moving when a new Data added.
This is my current code : (this function is called with a Timer every 200ms)

 QVector<QPointF> m_buffer =  chart_1->series()[0].serie->pointsVector();//currentSerie.serie->pointsVector() ;
    if(m_buffer.length() > 2000){
        m_buffer.remove(0);
    }

    ElapsedTimer .start(); //global variable
    chart_1->chart()->axes(Qt::Horizontal).back()->setMin(ElapsedTimer .elapsed());
    chart_1->chart()->axes(Qt::Horizontal).back()->setMax(ElapsedTimer .elapsed()+10);

    m_buffer.append(QPointF(QDateTime::currentDateTime().toMSecsSinceEpoch(), qrand() % ((10 + 1) - 1) + 1));
    chart_1->series()[0].serie->replace(m_buffer);

    QApplication::processEvents();

[jsulm]

@halima said in How to reset the time on x-axis of a graph?:

void MaClasse::updateChart(){
ElapsedTimer .start();

Why do you start the timer here?!

[halima]

I'm using two timers :

//first timer to execute slot 
QTimer *timer 
 connect(timer,&QTimer::timeout,this,&CL_SubWin_Chart::updateChart);
timer->start(200);
//second timer to update XAxis
void MaClasse::updateChart(){
 QElapsedTimer ElapsedTimer;
ElapsedTimer .start();

chart_1->chart()->axes(Qt::Horizontal).back()->setMin(ElapsedTimer .elapsed());
chart_1->chart()->axes(Qt::Horizontal).back()->setMax(ElapsedTimer .elapsed()+10);
...
}

But the xAxis not move!

[jsulm]

@halima But why do you need this ElapsedTimer which you start inside updateChart()?
You will always get more or less same value from elapsed() I think.

[halima]

@jsulm you're right it works without this timer but I do this to update xAxis values because I need to have a real time ploting .

The chart serie start like this :

The final Chart, New Data after09:58:56 is not displayed!

[jsulm]

@halima I suggest to move

QElapsedTimer ElapsedTimer;

to your MaClasse (as member variable)
And this to the constructor:

ElapsedTimer .start();

then it should work.

[halima]

@jsulm i did this and it's still not working :(

//constructor
MaClasse::MaClasse(){   
    ElapsedTimer .start();
}

//slot
void void MaClasse::updateChart(){

    QVector<QPointF> m_buffer =  chart_1->series()[0].serie->pointsVector();
    if(m_buffer.length() > 2000){       
        m_buffer.remove(0);
    }

    chart_1->chart()->axes(Qt::Horizontal).back()->setMin(ElapsedTimer .elapsed());
    chart_1->chart()->axes(Qt::Horizontal).back()->setMax(ElapsedTimer .elapsed()+10);

    m_buffer.append(QPointF(QDateTime::currentDateTime().toMSecsSinceEpoch(), qrand() % ((10 + 1) - 1) + 1));
    chart_1->series()[0].serie->replace(m_buffer);

    QApplication::processEvents();
}

[halima]

I solved the problem with doing this :

 chart_1->chart()->axes(Qt::Horizontal).back()->setMin(QDateTime::fromMSecsSinceEpoch(m_buffer[0].x()));
    chart_1->chart()->axes(Qt::Horizontal).back()->setMax(QDateTime::currentDateTime().addSecs(1));

it works perfectly.
Thank you guys! @jsulm @VRonin