在gdi绘图中可以用来定义path的函数有:
AngleArc Arc ArcTo Chord CloseFigure Ellipse ExtTextOut LineTo MoveToEx Pie PolyBezier PolyBezierTo PolyDraw Polygon PolyLine PolylineTo PolyPolygon PolyPolyline Rectangle RoundRect TextOut
可用GetPath重新定义路径
可用SelectClipPath设置路径为裁剪路径