/// <summary> /// 判断圆C是否在多边形PG内 /// </summary> /// <param name="PG">PG多边形</param> /// <param name="C">圆C</param> /// <returns>如果圆C在区域内返回True,否则返回False.</returns> public static Boolean InPolygon(PolygonI PG, CircleI C) { //如果圆心不在多边形内则返回不在多边形内 if (false == InPolygon(PG, C.Center)) { return(false); } Double D = PointAlgorithm.ClosestDistance(C.Center, PG); if (D > C.Radius || DoubleAlgorithm.Equals(D, C.Radius)) { return(true); } return(false); }
/// <summary> /// 判断线段L与圆C的交点个数 /// </summary> /// <param name="L">线段L</param> /// <param name="C">圆形C</param> /// <returns>相交返回交点数目,否则返回0</returns> public static Int32?HasIntersection(LineI L, CircleI C) { Int32 count = 0; //如果和圆C有交点首先是L到圆心的距离小于或等于C的半径 if (DoubleAlgorithm.Equals(PointAlgorithm.ClosestDistance(C.Center, L), C.Radius)) { return(1); } else if (PointAlgorithm.ClosestDistance(C.Center, L) > C.Radius) { return(0); } if (PointAlgorithm.Distance(C.Center, L.Starting) >= C.Radius) { ++count; } if (PointAlgorithm.Distance(C.Center, L.End) >= C.Radius) { ++count; } return(count); }