Qwt中鼠标获取坐标点

 void getPoint(QwtPlot *plot)
 {
       QPoint point = plot->canvas()->mapFromGlobal(QCursor::pos());
       QString info.sprintf("x = %g, y = %g",
                      plot ->invTransFrom(Qwtplot::xBottom,point.x()),
                      plot ->invTransFrom(Qwtplot::yLeft,point.y()
                       );
 }                    

Qwt获取坐标