using System;
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using System.Collections.Generic;
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using System.Linq;
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namespace IStation.Model
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{
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/// <summary>
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/// 曲线点列表拓展类
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/// </summary>
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public static class CurvePointList_Extensions
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{
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#region IEnumerable<CurvePoint>
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/// <summary>
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/// 获得X值的坐标位置,可能有多个点(是线形插值,不是曲线上的点)
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/// </summary>
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public static List<double> GetInterPointY(this IEnumerable<CurvePoint> src_list, double x)
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{
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if (src_list == null || src_list.Count() < 1)
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return default;
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var list = src_list.ToList();
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var equalPoints = new List<double>();
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int num = src_list.Count();
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for (int i = 0; i < num - 1; i++)//少一个点
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{
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if ((x >= list[i].X && x <= list[i + 1].X) || (x <= list[i].X && x >= list[i + 1].X))
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{//直线插值
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double y;
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if (Math.Abs(list[i].X - list[i + 1].X) < 0.01)
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y = (list[i].Y + list[i + 1].Y) * 0.5;
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else
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y = list[i].Y + (list[i + 1].Y - list[i].Y) * (x - list[i].X) / (list[i + 1].X - list[i].X);
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equalPoints.Add(y);
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}
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}
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return equalPoints;
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}
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/// <summary>
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/// 计算总长度
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/// </summary>
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public static double CalcuTotalLength(this IEnumerable<CurvePoint> src_list)
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{
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if (src_list == null || src_list.Count() < 2)
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return default;
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var list = src_list.ToList();
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double length = 0;
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for (int i = 1; i < list.Count(); i++)
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{
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double len = Math.Sqrt((list[i].X - list[i - 1].X) * (list[i].X - list[i - 1].X) + (list[i].Y - list[i - 1].Y) * (list[i].Y - list[i - 1].Y));
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length += len;
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}
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return length;
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}
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/// <summary>
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/// 计算总长度 count(计算的点数量)
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/// </summary>
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public static double CalcuTotalLength(this IEnumerable<CurvePoint> src_list, int count)
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{
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if (src_list == null || src_list.Count() < 2)
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return default;
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var list = src_list.ToList();
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int count_min = Math.Min(src_list.Count(), count);
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double length = 0;
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for (int i = 1; i < count_min; i++)
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{
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double len = Math.Sqrt((list[i].X - list[i - 1].X) * (list[i].X - list[i - 1].X) + (list[i].Y - list[i - 1].Y) * (list[i].Y - list[i - 1].Y));
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length += len;
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}
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return length;
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}
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/// <summary>
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/// 根据总长度获取点 超越总长度返回NULL
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/// </summary>
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public static CurvePoint GetPointByLength(this IEnumerable<CurvePoint> src_list, double length_from_start)
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{
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if (src_list == null || src_list.Count() < 1)
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return default;
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if (length_from_start < 0.0001)
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{
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return src_list.FirstOrDefault();
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}
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var list = src_list.ToList();
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double length = 0;
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for (int i = 1; i < list.Count; i++)
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{
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double len_line = Math.Sqrt((list[i].X - list[i - 1].X) * (list[i].X - list[i - 1].X) + (list[i].Y - list[i - 1].Y) * (list[i].Y - list[i - 1].Y));
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length += len_line;
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if (length >= length_from_start)
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{
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var extPt = new CurvePoint();
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extPt.X = (list[i - 1].X - list[i].X) * (length - length_from_start) / len_line + list[i].X;
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extPt.Y = (list[i - 1].Y - list[i].Y) * (length - length_from_start) / len_line + list[i].Y;
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return extPt;
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}
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}
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if (length >= length_from_start * 0.9999)
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{
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return list.LastOrDefault();
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}
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return default;
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}
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/// <summary>
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/// 获取Y最大的点
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/// </summary>
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public static CurvePoint GetPointByMaxY(this IEnumerable<CurvePoint> src_list)
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{
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if (src_list == null || src_list.Count() < 1)
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return default;
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var y_max = src_list.Max(x => x.Y);
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return (from x in src_list where x.Y == y_max select x).FirstOrDefault();
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}
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/// <summary>
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/// 获取Y最小的点
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/// </summary>
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public static CurvePoint GetPointByMinY(this IEnumerable<CurvePoint> src_list)
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{
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if (src_list == null || src_list.Count() < 1)
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return default;
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var y_min = src_list.Min(x => x.Y);
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return (from x in src_list where x.Y == y_min select x).FirstOrDefault();
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}
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/// <summary>
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/// 获取Y最大的点索引
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/// </summary>
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public static int GetPointIndexByMaxY(this IEnumerable<CurvePoint> src_list)
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{
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if (src_list == null || src_list.Count() < 1)
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return -1;
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var y_max = src_list.Max(x => x.Y);
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return src_list.ToList().FindIndex(x => x.Y == y_max);
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}
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/// <summary>
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/// 获取Y最小的点索引
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/// </summary>
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public static int GetPointIndexByMinY(this IEnumerable<CurvePoint> src_list)
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{
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if (src_list == null || src_list.Count() < 1)
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return -1;
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var y_min = src_list.Min(x => x.Y);
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return src_list.ToList().FindIndex(x => x.Y == y_min);
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}
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/// <summary>
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/// 根据X 获取点索引
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/// </summary>
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public static int GetPointIndexByX(this IEnumerable<CurvePoint> src_list, double x)
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{
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if (src_list == null || src_list.Count() < 1)
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return -1;
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int index = 0;
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foreach (var item in src_list)
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{
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if (Math.Abs(item.X - x) < 0.0001)
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return index;
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index++;
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}
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return -1;
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}
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/// <summary>
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/// 转化为存储字符串
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/// </summary>
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public static string ToDsString(this IEnumerable<CurvePoint> src_list)
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{
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return CurvePoint.ToDsString(src_list);
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}
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/// <summary>
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/// 移动点返回新的集合
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/// </summary>
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public static int MovePoint(this IEnumerable<CurvePoint> src_list, int index, int relative)
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{
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if (src_list == null || src_list.Count() < 1)
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return -1;
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if (index < 0 || index >= src_list.Count())
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return -1;
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var list = src_list.ToList();
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var p = list.ElementAt(index);
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list.RemoveAt(index);
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index += relative;
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if (index < 0)
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index = 0;
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if (index > list.Count)
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index = list.Count;
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list.Insert(index, p);
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src_list = list;
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return index;
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}
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/// <summary>
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/// 获取X方向距离最小的点
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/// </summary>
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public static CurvePoint GetClosestPointByX(this IEnumerable<CurvePoint> list, double x)
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{
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if (list == null || list.Count() < 1)
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return default;
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CurvePoint p = null;
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double min = double.MaxValue;
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foreach (var item in list)
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{
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var min_temp = Math.Abs(item.X - x);
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if (min_temp < min)
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{
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min = min_temp;
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p = item;
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}
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}
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return p;
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}
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/// <summary>
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/// 获取X方向距离最小的点索引
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/// </summary>
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public static int GetClosestPointIndexByX(this IEnumerable<CurvePoint> list, double x)
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{
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if (list == null || list.Count() < 1)
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return default;
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int index = 0;
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double min = double.MaxValue;
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for (int i = 0; i < list.Count(); i++)
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{
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var item = list.ElementAt(i);
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var min_temp = Math.Abs(item.X - x);
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if (min_temp < min)
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{
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min = min_temp;
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index = i;
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}
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}
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return index;
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}
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/// <summary>
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/// src_list 是一个多边形,判断点是否在多边形里
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/// 原理是 通过p做一个+X方向的射线, 偶数个交点 就是在外部,奇数个就是在内部
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/// </summary>
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public static bool IsInPolygon(this IEnumerable<CurvePoint> src_list, CurvePoint p, bool isClosed = true)
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{
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if (src_list == null || src_list.Count() < 1)
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return default;
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var list = src_list.ToList();
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int crossNum = 0;
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for (int i = 0; i < list.Count() - 1; i++)
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{
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if (p.IsIntersectLineLeft(list[i], list[i + 1]))
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{
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crossNum++;
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}
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}
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if (isClosed)
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{
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if (p.IsIntersectLineLeft(list[list.Count - 1], list[0]))
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{
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crossNum++;
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}
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}
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if ((crossNum % 2) == 0)
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return false;
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else
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return true;
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}
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#endregion
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}
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}
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