Custom symbol for QwtPlotMarker

[pkj]

1. Subclass QwtSymbol

class Symbol:public QwtSymbol
{
public:
    Symbol(const QBrush &, const QPen &, const QSize & ): QwtSymbol(QwtSymbol::NoSymbol, br, p, sz)
    void drawSymbol( QPainter *, const QPointF & ) const
{
 painter->setBrush( brush() );
    painter->setPen( pen() );
 
    const QSize sz = size();
    const int sw = sz.width();
    const int sh = sz.height();
    const int sw2 = sz.width() / 2;
    const int sh2 = sz.height() / 2;
 
 
    QPainterPath path;
    path.moveTo(pos);
    path.lineTo(pos.x()-sw2,pos.y()); path.lineTo(pos.x(),pos.y()+sh2);  path.lineTo(pos);
    painter->drawPath(path);
}
};

class Symbol:public QwtSymbol
{
public:
    Symbol(const QBrush &, const QPen &, const QSize & ): QwtSymbol(QwtSymbol::NoSymbol, br, p, sz)
    void drawSymbol( QPainter *, const QPointF & ) const
{
 painter->setBrush( brush() );
    painter->setPen( pen() );

    const QSize sz = size();
    const int sw = sz.width();
    const int sh = sz.height();
    const int sw2 = sz.width() / 2;
    const int sh2 = sz.height() / 2;

    
    QPainterPath path;
    path.moveTo(pos);
    path.lineTo(pos.x()-sw2,pos.y()); path.lineTo(pos.x(),pos.y()+sh2);  path.lineTo(pos);
    painter->drawPath(path);
}
};

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2.Subclass QwtPlotMarker

class Marker:public QwtPlotMarker
{
public:
    Marker():QwtPlotMarker(){}
    void drawAt( QPainter *, const QRectF &, const QPointF & ) const   
   {
           symbol().drawSymbol(painter, pos);
           QwtPlotMarker::drawAt(painter, rect, pos);
    }
};

class Marker:public QwtPlotMarker
{
public:
    Marker():QwtPlotMarker(){}
    void drawAt( QPainter *, const QRectF &, const QPointF & ) const   
   {
           symbol().drawSymbol(painter, pos);
           QwtPlotMarker::drawAt(painter, rect, pos);
    }
};

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3. instantiate and use
........

Marker *mrk = new Marker();
    mrk->setLinePen(QPen(Qt::black, 0, Qt::DashDotLine));    
    mrk->setLineStyle(QwtPlotMarker::HLine);
    mrk->setSymbol(new Symbol(QColor(Qt::yellow), QColor(Qt::green), QSize(15,15)));
    mrk->setValue(10.0,10.0);

Marker *mrk = new Marker();
    mrk->setLinePen(QPen(Qt::black, 0, Qt::DashDotLine));    
    mrk->setLineStyle(QwtPlotMarker::HLine);
    mrk->setSymbol(new Symbol(QColor(Qt::yellow), QColor(Qt::green), QSize(15,15)));
    mrk->setValue(10.0,10.0);

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............

Problem I face:while the marker is displayed fine, symbol is not drawn...