原理:

1.先计算出圆心(结果有两个值一个在两个点的连线上面一个在两个点的下面)

2.选择圆心,计算两点之间指定个数点的坐标

3.将坐标集合以线的形式绘制出来(点越多越接近圆)

openlayers 根据起点和终点半径画圆弧_openlayers 绘制圆弧

图上根据选择的圆心绘制了两个反方向的圆弧,中间横线为两点之间的连线用来验证坐标计算的


计算坐标的代码tool.js

function get_circle(point_s, point_e, radius, flag = true) {
//返回结果变量 let x0, y0, x1, y1
//计算过程 if (point_e[0] == point_s[0]) {
y0 = y1 = (point_s[1] + point_e[1]) / 2 let delta_y = (y0 - point_s[1]) ** 2 let delta_x = .sqrt(radius ** 2 - delta_y)
x0 = point_e[0] - delta_x
x1 = point_e[0] + delta_x
} else {
let C1 = (point_e[0] ** 2 + point_e[1] ** 2 - point_s[0] ** 2 - point_s[1] ** 2) / 2 / (point_e[0] - point_s[0])
let C2 = (point_e[1] - point_s[1]) / (point_e[0] - point_s[0])
let A = 1 + C2 ** 2 let B = 2 * (point_s[0] - C1) * C2 - 2 * point_s[1]
let C = (point_s[0] - C1) ** 2 + point_s[1] ** 2 - radius ** 2 y0 = (-B + .sqrt(B * B - 4 * A * C)) / 2 / A
y1 = (-B - .sqrt(B * B - 4 * A * C)) / 2 / A
x0 = C1 - C2 * y0
x1 = C1 - C2 * y1
}
//判断返回哪个圆心
if (flag) {
return [x1, y1]
} else {
return [x0, y0]
}

}

var rs_points = function rs_points(point_s, point_e, radius, dot_count, flag = true) {
let line = []
let rs = get_circle(point_s, point_e, radius,flag)
let a = rs[0], b = rs[1]
let ad_len = 0
let y = 0
//计算x坐标的距离
ad_len =Math.abs(point_s[0] - point_e[0])

//根据需要打散的点数 计算每个x坐标
for (let i = 0; i < dot_count; i++) {
let x = point_s[0]
if (point_s[1] > point_e[1]) {
x = x + ad_len / dot_count * i
} else {
x = x + ad_len / dot_count * i
}
//计算指定x点的y坐标
if (flag) {
//如果返回的圆心上面
y = b + Math.sqrt(radius * radius - (x - a) * (x - a))
} else {
//如果返回的圆心下面
y = b - Math.sqrt(radius * radius - (x - a) * (x - a))
}
line.push([x, y])
}
line.push(point_e)
//返回所有在两点之间的圆弧上的点的集合
return line
}

exports.rs_points = rs_points