//

// STPoint.swift

// STBaseProject

//

// Created by 寒江孤影 on 2017/10/14.

//

import Foundation

import UIKit

public enum STGeometry {

/// 两点之间的直线距离

public static func distance(between start: CGPoint, and end: CGPoint) -> CGFloat {

hypot(abs(start.x - end.x), abs(start.y - end.y))

}

/// 圆上两点相对于圆心的夹角，返回角度制数值

public static func angle(

onCircleWithRadius radius: CGFloat,

center: CGPoint,

start: CGPoint,

end: CGPoint

) -> CGFloat {

let startVector = CGVector(dx: start.x - center.x, dy: start.y - center.y)

let endVector = CGVector(dx: end.x - center.x, dy: end.y - center.y)

let startAngle = atan2(startVector.dy, startVector.dx)

let endAngle = atan2(endVector.dy, endVector.dx)

let angle = (endAngle - startAngle) * 180 / .pi

return angle >= 0 ? angle : angle + 360

}

}