suanfa.h

用Visual C++编写的一个实现矩形窗口对多边形的裁剪！

#if !defined(ComputerGraphicsClass)
#define ComputerGraphicsClass

class CGraphics
{
public:
	CGraphics():PointCount(6),Point(NULL)
	{
		//CGraphics类的构造函数，初始化PointCount和Point
		Point = new CPoint[PointCount];
        Point[0] = CPoint(200,300);Point[1] = CPoint(300,300);
		Point[2] = CPoint(400,200);Point[3] = CPoint(300,100);
		Point[4] = CPoint(200,100);Point[5] = CPoint(100,200);
       //六个点为正六边形六个顶点

	}
	~CGraphics()
	{
		//析构函数，删除动态生成的Point指针
		if(Point)
			delete [] Point;
	};
	bool DrawPloyon(CDC*);
	//在指定设备中，画多边形
	bool InterCross(CPoint,CPoint,CPoint,CPoint,CPoint&);
	//判断两条线段是否相交
	bool CutRect(CRect);
	//对多边形进行裁减
	bool IsInSquareRgn(CRect,CPoint,int);
	//对多边形裁减时，判断线段端点是否在可视一侧
	int AfterIndex(int i)
	{
		return (i == PointCount-1)?0:i+1;
	}
	//获取下一个点的索引号
	int BeforeIndex(int i)
	{
		return (i == 0 )? PointCount-1:i-1;
	}
	//获取前一个点的索引号
public:
	CPoint *Point;
	//指向点坐标的指针
	int PointCount;
	//多边形点的个数
};



#endif