如何使用Javascript找到给出2个点和距离的点的坐标

Question

我有2个点A1（x1，y1）和A2（x2，y2）的坐标以及距离d。我需要在由A1和A2定义的线性图上找到点A3的坐标，该坐标是到点A2的距离d。如何使用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 已知角度的情况

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);