//-----------------------------------------------------------------// This class shows how to extend QwtPlotItems. It displays a// pie chart of user/total/idle cpu usage in percent.//-----------------------------------------------------------------#include <qwt_plot_item.h>class CpuPieMarker: public QwtPlotItem{public:    CpuPieMarker();    virtual int rtti() const;    virtual void draw(QPainter *p,        const QwtScaleMap &, const QwtScaleMap &,        const QRect &rect) const;};