QT Doubt plotting path of points

I receive positions on the plane and I want to draw the route. It is not a line, but a path... that is, I receive each point and generate a polygon that has a "working width" of 7, then each point I receive, I generate a polygon with a width of 7 and I join them . This is the code I generated:

void WorkedPathGraph::addPointToDraw(QPointF point)
{
    if (points.count() == 0)
        points.append(point);
    else
    {
        QPointF lastIns = points.last();
        QLineF aux1;
        aux1.setP1(lastIns);
        aux1.setP2(point);
        aux1.setLength(_anchoLabor / 2);
        aux1 = aux1.normalVector();

        QLineF lpt1;
        lpt1.setP1(aux1.p2());
        lpt1.setP2(aux1.p1());
        lpt1.setLength(_anchoLabor);

        QLineF aux2;
        aux2.setP1(point);
        aux2.setP2(lastIns);
        aux2.setLength(_anchoLabor / 2);
        aux2 = aux2.normalVector();

        QLineF lpt2;
        lpt2.setP1(aux2.p2());
        lpt2.setP2(aux2.p1());
        lpt2.setLength(_anchoLabor);

        QPolygonF newPol = QPolygonF(QVector<QPointF>() << lpt1.p1() << 
                 lpt1.p2() << lpt2.p1() << lpt2.p2());

        areas.append(newPol);
        path.addPolygon(newPol);

        points.append(point);
    }
    this->parentItem()->update();
}

What I do there is take the point I receive and help me with the previous one so that if it moved to one side, I take the perpendicular to the line that generates that point with the previous one to generate the polygon. ALL those polygons, I insert them in a QPainterPathand I draw them... BUT the graph comes out cut off... I need it to come out neat and the curves more CURVED. I leave you an image of how it looks to see if someone can guide me to improve it.

• areasis a QVector<QPolygonF>, which I use to accumulate the polygons and add the area that the machine covers.
• pointsis a QVector<QPointF>, that I accumulate the points that I receive to generate the polygons between the point that I receive and the last one that is stored in points.
• pathIt is a QPainterPaththat there I throw all the polygons to paint.

In the PAINT method what I do is:

void WorkedPathGraph::paint(QPainter *painter, const QStyleOptionGraphicsItem *item, QWidget *widget)
{
    Q_UNUSED(widget);

    QPen qpen, qpenOld;
    QBrush oldBrush;
    qpen.setColor(QColor(0, 255, 0, 128));

    qpen.setWidth(1);
    qpen.setCosmetic(true);

    qpenOld = painter->pen();
    oldBrush = painter->brush();
    painter->setPen(qpen);

    painter->setClipRect(item->exposedRect);
    painter->setBrush(QColor(0,255,0, 128));

    painter->drawPath(path.simplified());
    painter->setPen(qpenOld);
   painter->setBrush(oldBrush);
}

The idea is that there would be something like this (It doesn't have the same shape because I did it in paint):