63 lines
1.9 KiB
C#
63 lines
1.9 KiB
C#
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using System;
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using System.Collections.Generic;
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using System.Drawing;
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using System.Linq;
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using System.Text;
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namespace Io.Github.Kerwinxu.LibShapes.Utils
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{
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/// <summary>
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/// 距离计算的类，
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/// </summary>
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public class DistanceCalculation
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{
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/// <summary>
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/// 选择的容忍度
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/// </summary>
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public static float select_tolerance = 1f;
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/// <summary>
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/// 两点之间的距离
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/// </summary>
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/// <param name="p1"></param>
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/// <param name="p2"></param>
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/// <returns></returns>
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public static float distance(PointF p1, PointF p2)
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{
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return (float)Math.Sqrt((p1.X - p2.X) * (p1.X - p2.X) + (p1.Y - p2.Y) * (p1.Y - p2.Y));
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}
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/// <summary>
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/// 点到线段的距离
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/// </summary>
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/// <param name="p0">点</param>
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/// <param name="p1">线段的点1</param>
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/// <param name="p2">线段的点2</param>
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/// <returns></returns>
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public static float pointToLine(PointF p0, PointF p1, PointF p2)
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{
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float a = distance(p1, p2); // 求出这个线段的长度
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float b = distance(p0, p1); // 这个点跟线段的点1的长度
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float c = distance(p0, p2); // 这个点跟线段的点2的长度
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// 这里分几种情况
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if (c*c >= a*a + b*b)
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{
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// 如果这个特别的长，那么这个点就不考虑距离了
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return b;
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}else if(b*b >= a * a + c * c)
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{
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// 同理
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return c;
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}
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else
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{
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float p = (a + b + c) / 2; // 半周长
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double s = Math.Sqrt(p * (p - a) * (p - b) * (p - c)); // 海伦公式求面积
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return (float)(2 * s / a); // 返回点到线的距离
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}
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}
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}
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}
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