Is that any problem in my this function?

[HelloDan]

// draw plotter line using QPainter function drawPolyline
void GenePlotter::drawPlotterLine(QPainter *painter)
{
  	 QRect rect(Margin, Margin,
               width() - 2 * Margin, height() - 2 * Margin);
    if (!rect.isValid())
        return;
 
    painter->setClipRect(rect.adjusted(+1, +1, -1, -1));
 
    //draw best lines
    painter->setPen(QPen(Qt::red,1.0));
    const QPointF* point=bestPoints.data();        //bestPoints is a vector
    painter->drawPolyline(point,bestPoints.size()); 
 
 
 
    //draw average line
    painter->setPen(QPen(Qt::blue,1.0));   //X is the same
    point=avgPoints.data();                //avgPoints is also a vector
    painter->drawPolyline(point,avgPoints.size());

// draw plotter line using QPainter function drawPolyline
void GenePlotter::drawPlotterLine(QPainter *painter)
{
  	 QRect rect(Margin, Margin,
               width() - 2 * Margin, height() - 2 * Margin);
    if (!rect.isValid())
        return;

    painter->setClipRect(rect.adjusted(+1, +1, -1, -1));
    
    //draw best lines
    painter->setPen(QPen(Qt::red,1.0));
    const QPointF* point=bestPoints.data();        //bestPoints is a vector
    painter->drawPolyline(point,bestPoints.size()); 
   
    
    
    //draw average line
    painter->setPen(QPen(Qt::blue,1.0));   //X is the same
    point=avgPoints.data();                //avgPoints is also a vector
    painter->drawPolyline(point,avgPoints.size());

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Is that any problem in the above code? That's something wrong, But I cann't tell. It fails to draw the average line.

Thanks