C# 判断两条直线是否相交

直接上代码,过程不复杂

/// <summary>/// 判断两条线是否相交/// </summary>/// <param name="a">线段1起点坐标</param>/// <param name="b">线段1终点坐标</param>/// <param name="c">线段2起点坐标</param>/// <param name="d">线段2终点坐标</param>/// <param name="intersection">相交点坐标</param>/// <returns>是否相交 0:两线平行  -1:不平行且未相交  1:两线相交</returns>PRivate int GetIntersection(Point a, Point b, Point c, Point d ,ref Point intersection){    //判断异常    if (Math.Abs(b.X - a.Y) + Math.Abs(b.X - a.X) + Math.Abs(d.Y - c.Y) + Math.Abs(d.X - c.X) == 0)    {        if (c.X - a.X == 0)        {           Debug.Print("ABCD是同一个点！");         }        else        {            Debug.Print("AB是一个点，CD是一个点，且AC不同！");        }        return 0;    }    if (Math.Abs(b.Y - a.Y) + Math.Abs(b.X - a.X) == 0)    {        if ((a.X - d.X) * (c.Y - d.Y) - (a.Y - d.Y) * (c.X - d.X) == 0)        {            Debug.Print ("A、B是一个点，且在CD线段上！");        }        else        {             Debug.Print ("A、B是一个点，且不在CD线段上！");        }        return 0;    }    if (Math.Abs(d.Y - c.Y) + Math.Abs(d.X - c.X) == 0)    {        if ((d.X - b.X) * (a.Y - b.Y) - (d.Y - b.Y) * (a.X - b.X) == 0)        {            Debug.Print ("C、D是一个点，且在AB线段上！");        }        else        {            Debug.Print ("C、D是一个点，且不在AB线段上！");        }    }    if ((b.Y - a.Y) * (c.X - d.X) - (b.X - a.X) * (c.Y - d.Y) == 0)    {        Debug.Print ("线段平行，无交点！");        return 0;    }       intersection.X = ((b.X - a.X) * (c.X - d.X) * (c.Y - a.Y) - c.X * (b.X - a.X) * (c.Y - d.Y) + a.X * (b.Y - a.Y) * (c.X - d.X)) / ((b.Y - a.Y) * (c.X - d.X) - (b.X - a.X) * (c.Y - d.Y));    intersection.Y = ((b.Y - a.Y) * (c.Y - d.Y) * (c.X - a.X) - c.Y * (b.Y - a.Y) * (c.X - d.X) + a.Y * (b.X - a.X) * (c.Y - d.Y)) / ((b.X - a.X) * (c.Y - d.Y) - (b.Y - a.Y) * (c.X - d.X));       if ((intersection.X - a.X) * (intersection.X - b.X) <= 0 && (intersection.X - c.X) * (intersection.X - d.X) <= 0 && (intersection.Y - a.Y) * (intersection.Y - b.Y) <= 0 && (intersection.Y - c.Y) * (intersection.Y - d.Y) <= 0)    {        Debug.Print ("线段相交于点(" + intersection.X + "," + intersection.Y + ")！");        return 1; //'相交    }    else    {        Debug.Print ("线段相交于虚交点(" + intersection.X + "," + intersection.Y + ")！");        return -1; //'相交但不在线段上    }}