/// <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);
}
