package com.demo.navtogether.utils;
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import android.graphics.Point;
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/**
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* My father is Object, ites purpose of 三角函数算法
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*
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* @purpose Created by Runt (qingingrunt2010@qq.com) on 2020-12-23.
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*/
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public class TriangleUtils {
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public static void main(String[] args) {
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Point pA = new Point(0,11),pB = new Point(11,30),pC = new Point(30,30);
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double a = getLengthOfSide(pA,pB),b = getLengthOfSide(pC,pB),c = getLengthOfSide(pA,pC);
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System.out.println(String.format("边长 a:%s,b:%s,c:%s",a,b,c));
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System.out.println(String.format("角度 坐标计算：a:%s,b:%s,c:%s",getDegrees(pA,pB,pC),getDegrees(pB,pC,pA),getDegrees(pC,pA,pB)));
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System.out.println(String.format("角度 转换为边长计算：a:%s,b:%s,c:%s",getDegrees2(pA,pB,pC),getDegrees2(pB,pC,pA),getDegrees2(pC,pA,pB)));
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System.out.println(String.format("角度 边长计算：a:%s,b:%s,c:%s",getDegrees(a,b,c),getDegrees(b,c,a),getDegrees(c,a,b)));
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System.out.println("边长 c："+getHypotenuseFromLength(a,b ));
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System.out.println("边长 c："+getLengthOfSide(a,b ,getDegrees2(pA,pB,pC)));
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System.out.format("%s 度的余弦值为 %s", Math.toRadians(90), Math.cos(Math.toRadians(90)));
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}
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/************************直角三角算法*******************************/
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/**
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* 直角三角获取斜边
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* @param a 直角边长
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* @param b 直角边长
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* @return 斜边边长
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*/
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public static Double getHypotenuseFromLength(double a,double b){
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return Math.sqrt(a*a+b*b);
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}
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/**
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* 直角三角形 根据角度和直角边长求斜边
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* @param degree 角度
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* @param width 直角边长
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* @return 斜边边长
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*/
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public static double getHypotenuseFromDegree(double degree,double width){
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double cos = Math.cos(Math.toRadians(degree));//余弦
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return width / cos;
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}
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/**
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* 直角三角形 根据角度和斜边求直角边
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* @param degree 角度
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* @param width 斜边
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* @return 斜边边长
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*/
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public static double getRightSideFromDegree(double degree,double width){
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double cos = Math.cos(Math.toRadians(degree));
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return width * cos;
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}
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/**
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* 直角三角形 根据直角边和斜边求直角边
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* @param a 直角边
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* @param b 斜边
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* @return 直角边长
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*/
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public static double getRightSideFromLength(double a,double b){
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return Math.sqrt(b*b - a*a);
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}
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/************************end 直角三角算法*******************************/
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/**
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* 根据 B角和C角的a边长，获取A角-C角的b边长
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* @param A
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* @param B
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* @param a
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* @return
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*/
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public static double getSideFromSideAndDegree(double A,double B,double a){
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// a÷sin A == b ÷ sin B
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return a/Math.sin(Math.toRadians(A))*Math.sin(Math.toRadians(B));
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}
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/**
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* 获取对边
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* @param a 边长
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* @param b 边长
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* @param degrees 角度
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* @return
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*/
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public static Double getLengthOfSide(double a,double b,double degrees){
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System.out.println(String.format("a:%s,b:%s,degrees:%s",a,b,degrees));
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return Math.sqrt(b*b+a*a-2*a*b*Math.cos(Math.toRadians(degrees)));
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}
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/**
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* 已知边长 求AC 角度
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* @param a
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* @param b
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* @param c
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* @return
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*/
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public static double getDegrees(double a,double b,double c){
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// 计算弧度表示的角
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double degrees = Math.acos((a*a + b*b -c*c)/(2.0*a*b));
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// 用角度表示的角
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return Math.toDegrees(degrees);
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}
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/**
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* 两点之间的长度
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* @param point0 坐标
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* @param point1 坐标
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* @return
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*/
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public static double getLengthOfSide(Point point0, Point point1){
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return Math.sqrt(Math.pow((point0.x-point1.x),2)+Math.pow((point0.y-point1.y),2));
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}
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/**
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* 根据坐标 获取角度
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* @param point0 坐标
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* @param degreesPoint 坐标 获取该点的角度
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* @param point2 坐标
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* @return
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*/
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public static int getDegrees(Point point0, Point degreesPoint, Point point2) {
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//向量的点乘
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int vector = (point0.x - degreesPoint.x) * (point2.x - degreesPoint.x) + (point0.y - degreesPoint.y) * (point2.y - degreesPoint.y);
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//向量的模乘
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double sqrt = Math.sqrt(
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(Math.abs((point0.x - degreesPoint.x) * (point0.x - degreesPoint.x)) + Math.abs((point0.y - degreesPoint.y) * (point0.y - degreesPoint.y)))
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* (Math.abs((point2.x - degreesPoint.x) * (point2.x - degreesPoint.x)) + Math.abs((point2.y - degreesPoint.y) * (point2.y - degreesPoint.y)))
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);
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//反余弦计算弧度
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double radian = Math.acos(vector / sqrt);
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//弧度转角度制
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return (int) (180 * radian / Math.PI);
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}
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/**
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* 根据坐标 获取角度
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* @param pA 坐标
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* @param degreesPoint 坐标 获取该点的角度
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* @param pC 坐标
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* @return
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*/
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public static double getDegrees2(Point pA, Point degreesPoint, Point pC) {
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double a = getLengthOfSide(pA,degreesPoint),b = getLengthOfSide(pC,degreesPoint),c = getLengthOfSide(pA,pC);
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return getDegrees(a,b,c);
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}
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}
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