程序想判断point是否在LT,RT,LB,RB这四个点所围成的区域里，说是用qpolygonf，这个程序怎么不行啊。。
QPointF p1=QPointF(-20,-20);
QPointF p2=QPointF(20,20);
QPointF *LT=new QPointF(p1.x(),p1.y()-2.5);
QPointF *RB=new QPointFp1.x(),p1.y()+2.5);
QPointF *RT=new QPointF(p2.x(),p2.y()-2.5);
QPointF *LB=new QPointF(p2.x(),p2.y()+2.5);
QVector<QPointF> *vec=new QVector<QPointF>;
vec->append(*LT);
vec->append(*RB);
vec->append(*RT);
vec->append(*LB);
QPolygonF *poly=new QPolygonF(*vec);
if (poly->containsPoint(point,Qt::OddEvenFill))
return 0;
