如何找到用 Javascript 给出 2 个点和距离的点的坐标

Question

我有 2 个点 A1 (x1,y1) 和 A2 (x2,y2) 的坐标和距离 d。我需要在 A1 和 A2 定义的线性图上找到点 A3 的坐标，即距点 A2 的距离 d。我怎样才能用 JavaScript 做到这一点？类似于 https://softwareengineering.stackexchange.com/questions/179389/find-the-new-coordinates-using-a-starting-point-a-distance-and-an-angle 其中角度已知

Answer 1

var A1 = {
    x : 2,
    y : 2
};

var A2 = {
    x : 4,
    y : 4
};

// Distance
var  d= 2;

// Find Slope of the line
var slope = (A2.y-A1.y)/(A2.x-A1.x);

// Find angle of line
var theta = Math.atan(slope);

// the coordinates of the A3 Point
var A3x= A2.x + d * Math.cos(theta);
var A3y= A2.y + d * Math.sin(theta);

console.log(A3x);
console.log(A3y);

Answer 2

所以你要从A1开始往A2方向走A1和A2的距离+d
假设您的点是具有 x 和 y 属性以及距离方法的点 class 的对象，您可以这样做：

function move_to(origin, direction, dist){
    let dx = direction.x - origin.x;
    let dy = direction.y - origin.y;
    let coef = dist / origin.distance(direction);

    let x = origin.x + dx * coef;
    let y = origin.y + dy *coef;
    return new Point(x, y)
}

move_to(A1, A2, A1.distance(A2) + d)

如果需要，这里有一个简单的要点 class 实现：

class Point {

    constructor(x, y){
        this.x = x;
        this.y = y;
    }

    distance(point){
        return Math.sqrt((this.x - point.x) ** 2 + (this.y - point.y) ** 2)
    }

}

如何找到用 Javascript 给出 2 个点和距离的点的坐标

How to find coordinates of a point where 2 points and distance are given with Javascript

javascript

line

points

calculation