Best AntiAliasing?

[beni46]

I build an application which draw curve with Qwt.

I obtain this picture:

Picture 10.png


On this picture there are still some "stairs" in curve like when you didn't activate Anti-Aliasing but anti Aliasing are activate.

The function which attach curve to the plot:

void CurveControl::addShapeRep(ACShapeRep *shape)
{
    QVector<double> x;
    QVector<double> y;
    QwtPlotCurve * currentCurve = new QwtPlotCurve();
 
    // Add the curve to the canvas
    QList<QPointF> * tempShapeRep = shape->getShapeRep();
 
    // Adjust Axis with this new curve
    adjustAxis(shape);
 
    for(int i = 0; i < tempShapeRep->count(); i++){
        x.append(tempShapeRep->at(i).x());
        y.append(tempShapeRep->at(i).y());
    }
 
    myCurveFitter = new QwtSplineCurveFitter();
    myCurveFitter->setFitMode(QwtSplineCurveFitter::Spline);
 
    currentCurve->setCurveAttribute(QwtPlotCurve::Fitted);
    currentCurve->setCurveFitter(myCurveFitter);
    currentCurve->setRenderHint(QwtPlotItem::RenderAntialiased, true);
    currentCurve->setData(x.data(),y.data(),x.size());
 
    currentCurve->setPen(shape->getShapePen());
 
    currentCurve->attach(plot);
 
    listOfPlotCurve->append(currentCurve);
 
    plot->replot();
}

void CurveControl::addShapeRep(ACShapeRep *shape)
{
    QVector<double> x;
    QVector<double> y;
    QwtPlotCurve * currentCurve = new QwtPlotCurve();

    // Add the curve to the canvas
    QList<QPointF> * tempShapeRep = shape->getShapeRep();

    // Adjust Axis with this new curve
    adjustAxis(shape);

    for(int i = 0; i < tempShapeRep->count(); i++){
        x.append(tempShapeRep->at(i).x());
        y.append(tempShapeRep->at(i).y());
    }

    myCurveFitter = new QwtSplineCurveFitter();
    myCurveFitter->setFitMode(QwtSplineCurveFitter::Spline);

    currentCurve->setCurveAttribute(QwtPlotCurve::Fitted);
    currentCurve->setCurveFitter(myCurveFitter);
    currentCurve->setRenderHint(QwtPlotItem::RenderAntialiased, true);
    currentCurve->setData(x.data(),y.data(),x.size());

    currentCurve->setPen(shape->getShapePen());

    currentCurve->attach(plot);

    listOfPlotCurve->append(currentCurve);

    plot->replot();
}

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Is it possible to obtain a better anti-aliasing with Qwt?

Thank you for your answer.

bye

[Uwe]

Reduce the number of your points.

Uwe

[beni46]

When I have look the code, I see that developper use QPoint and not QPointF to draw curve. They do that to conserve compatibility with previous version of Qwt.

In the Qwt 6.0, it will be improved.
Thank you for your help.

Bye