How to display multiple QwtPlotCurve plots?

Question

Qt

Hello! I'm trying to display multiple plots on QwtPlotCurve. Everything seems to be fine, but the charts are displayed only after the delay (Sleep(1000)) is executed after each call to the function of adding data to the chart.
function to add a graph to the drawing field

void Widget::GetCurve(QwtPlot *plot, Qt::GlobalColor colorLine)
{
    QwtPlotCurve *curve;
    QwtSymbol *symbol;
    QPolygonF *points;
    curve=new QwtPlotCurve();
    symbol= new QwtSymbol( QwtSymbol::Ellipse,
                           QBrush( Qt::yellow ), QPen( Qt::red, 2 ), QSize( 8, 8 ) );
    points = new QPolygonF;
    curve->setTitle("Demo Curve");
    curve->setPen(colorLine, 6); // цвет и толщина кривой
    curve->setRenderHint(QwtPlotItem::RenderAntialiased, true); // сглаживание
    curve->setSymbol(symbol);
    listCurve.append(curve);
    listCurve.last()->attach(plot);
}

function for adding data to the chart:

void Widget::AppendSamples()
{
    QVector<double> x;
    QVector<double> y;
    QList<QPointF> listPoint =  ReturnPointsList(150);
    int listPointCount = listPoint.count();  
    for (int i=0;i<listPointCount;i++)
    {
        x.append(listPoint[i].x());
        y.append(listPoint[i].y());
    }
     listCurve.last()->setSamples(x,y);
}

How it's all used:

GetCurve(listPlot.last(),Qt::red);
        AppendSamples();
       // Sleep::Sleeper(ms);
        GetCurve(listPlot.last(),Qt::green);
        AppendSamples();
        //Sleep::Sleeper(ms);
        GetCurve(listPlot.last(),Qt::black);
        AppendSamples();
       // Sleep::Sleeper(ms);
       listPlot.last()->replot();

Answer 1

I haven't worked with this component, but most likely the problem is that replot() needs to be called after each addition of a new curve, or setAutoReplot(true) on QwtPlot after object creation (although the first option is probably better).

Answer 2

After calling replot, you should be in the event loop. Is this happening to you?