Unsolved how to drag and drop of a QwtPlotCurve inside the QwtPlotCanvas?

[thippu]

Hi @uwer,
I want a user to change the position of QwtPlotCurve on QwtPlotCanvas (like drag and drop on the canvas)
So, I did refer the ItemEditor example of the Qwt lib.
How do I convert these lines for QwtPlotCurve instead QwtPlotShapeItem?
In the

bool Editor::moved(const QPointF& pos)
{
//you can assume above this code is  same as the example code 
//only part of the code which is not understood by me, I'm asking here
//I don't know to how to convert following codes according to QwtPlotCurve instead of QwtPlotShapeItem, please help me

#if QT_VERSION>=0x040600
const QPainterPath shape=d_editedItem->shape().translated(p2-p1);// I have declared d_editedItem as QwtPlotCurve* instead of QwtPlotShapeItem*
#else
const double dx=p2.x()-p1.x();
const double dy=p2.y()-p1.y();
QPainterPath shape=d_editedItem->shape();
for(int i=0;i<shape.elementCount();i++)
{
 const QPainterPath::Element &el=shape.elementAt(i);
 shape.setElementPositionAt(i,el.x+dx,el.y+dy);
}
#endif
d_editedItem->setShape(shape);
d_currentPos=pos;
return true;