该方法可以用来求延长线坐标
let y3 =this.k_fun(x1, y1, x2, y2, x3)/**求延长线坐标方法 */privatek_fun(x1, y1, x2, y2, x3, y3?){// x1 y1起点// x2 y2终点// x3 y3 设置一个求一个 只能设置一个未知数// let x1 = 1// let y1 = 1// let x2 = 3// let y2 = 2// let x3// let y3 = 4// 斜率公式let b
let k =(x1 - x2)/(y1 - y2)console.log(k,"k")if(x3){
b =(x1 - x2)/ k
y3 = y1 - b
console.log(y3,"y3")return y3
}if(y3){
b = k *(y1 - y3)
x3 = x1 - b
console.log(x3,"x3")return x3
}// b = k * (y1 - y3)}