/// <summary>
/// 计算点P到折线PL的最近距离
/// </summary>
/// <param name="P">点P</param>
/// <param name="PL">折线PL</param>
/// <returns>返回最近距离</returns>
public static Double ClosestDistance(PointI P, PolylineI PL)
{
Double result = Double.MaxValue;
foreach (LineI S in PL)
{
result = System.Math.Min(result, ClosestDistance(P, S));
}
return(result);
}
/// <summary>
/// 计算偏移折线PL
/// </summary>
/// <param name="PL">折线PL</param>
/// <param name="velocity">偏移速度</param>
/// <returns>返回偏移折线</returns>
public static PolylineI Offset(PolylineI PL, PointI velocity)
{
List <PointI> list = new List <PointI>();
for (Int32 i = 0; i < PL.Points.Count; ++i)
{
list.Add(PL.Points[i] + velocity);
}
return(new PolylineI(list.ToArray()));
}
/// <summary>
/// 判断折线PL是否在多边形内
/// </summary>
/// <param name="PG">PG多边形</param>
/// <param name="PL">PL折线</param>
/// <returns>如果PL折线在区域内返回True,否则返回False.</returns>
public static Boolean InPolygon(PolygonI PG, PolylineI PL)
{
foreach (LineI L in PL)
{
if (InPolygon(PG, L) == false)
{
return(false);
}
}
return(true);
}
/// <summary>
/// 判断折线PL是否在圆内
/// </summary>
/// <param name="C">圆C</param>
/// <param name="PL">折线PL</param>
/// <returns>如果在圆内返回True，否则返回False。</returns>
public static Boolean InCircle(CircleI C, PolylineI PL)
{
if (PL.Points == null)
{
return(false);
}
for (Int32 i = 0; i < PL.Points.Count; ++i)
{
if (PointAlgorithm.Distance(PL.Points[i], C.Center) > C.Radius)
{
return(false);
}
}
return(true);
}
/// <summary>
/// 折线是否在区域内
/// </summary>
/// <param name="Rect">矩形区域</param>
/// <param name="PL">折线PL</param>
/// <returns>
/// 返回True表示折线PL在区域内，返回False则不在区域内.
/// </returns>
public static Boolean InRectangle(RectangleI Rect, PolylineI PL)
{
if (PL.Points == null)
{
return(false);
}
for (Int32 i = 0; i < PL.Points.Count; ++i)
{
if (false == InRectangle(Rect, PL.Points[i]))
{
return(false);
}
}
return(true);
}
/// <summary>
/// 获取线段L与折线PL的交点集合
/// </summary>
/// <param name="L">线段L</param>
/// <param name="PL">折线PL</param>
/// <returns>返回交点集合，如果有无数个交点则返回null.</returns>
public static PointD[] Intersection(LineI L, PolylineI PL)
{
List <PointD> result = new List <PointD>();
foreach (LineI S in PL)
{
PointD[] P = Intersection(L, S);
if (P == null)
{
return(null);
}
if (P.Length == 0)
{
continue;
}
if (result.Contains(P[0]) == false)
{
result.Add((PointD)P[0]);
}
}
return(result.ToArray());
}
/// <summary>
/// 判断折线PL与线段L的交点个数
/// </summary>
/// <param name="L">线段L</param>
/// <param name="PL">折线PL</param>
/// <returns>相交返回交点数目,否则返回0</returns>
public static Int32?HasIntersection(LineI L, PolylineI PL)
{
Int32 count = 0;
foreach (LineI S in PL)
{
Int32?result = HasIntersection(L, S);
if (result == null)
{
return(null);
}
count += (Int32)result;
}
for (Int32 i = 1; i < PL.Points.Count - 1; ++i)//排除折线的开始和结束顶点
{
if (OnLine(L, PL.Points[i]) == true)
{
count--;
}
}
return(count);
}
/// <summary>
/// 获取有效的折线
/// </summary>
/// <param name="PL">折线PL</param>
/// <returns>返回折线</returns>
public static PolylineI?GetValidatePolyline(PolylineI PL)
{
return((PolylineI)GetValidatePolyline((PolylineD)PL));
}
