Bezier path creation

gistfile1.swift

    func bezierPath(p1: CLLocationCoordinate2D, toPoint p2: CLLocationCoordinate2D, steps: Int = 100)
        -> [CLLocationCoordinate2D]
    {
        let auxiliaryPoint = self.fetchThirdPointByLocations(p1, p2: p2, angle: 90.0)
        var targetPoints = [CLLocationCoordinate2D]()
        
        let doubleSteps = Double(steps)
        for index in 0 ... steps {
            let t = Double(index) / doubleSteps

            // Start point of the Bezier curve
            let bezier1x = p1.longitude + (auxiliaryPoint.longitude - p1.longitude) * t
            let bezier1y = p1.latitude + (auxiliaryPoint.latitude - p1.latitude) * t
            
            // End point of the Bezier curve
            let bezier2x = auxiliaryPoint.longitude + (p2.longitude - auxiliaryPoint.longitude) * t
            let bezier2y = auxiliaryPoint.latitude + (p2.latitude - auxiliaryPoint.latitude) * t
            
            let bezierPoint = CLLocationCoordinate2D(latitude: bezier1y + (bezier2y - bezier1y) * t,
                longitude: bezier1x + (bezier2x - bezier1x) * t)
            targetPoints.append(bezierPoint)
        }
        
        return targetPoints
    }
    
    func fetchThirdPointByLocations(p1: CLLocationCoordinate2D, p2: CLLocationCoordinate2D, angle: Double)
        -> CLLocationCoordinate2D
    {
        let btpAngle = atan2(fabs(p1.latitude - p2.latitude), fabs(p1.longitude - p2.longitude)) * 180 / M_PI
        let center = CLLocationCoordinate2D(latitude: (p1.latitude + p2.latitude) / 2.0,
            longitude: (p1.longitude + p2.longitude) / 2.0)

        let a = (p1.latitude - p2.latitude) * (p1.latitude - p2.latitude)
        let b = (p1.longitude - p2.longitude) * (p1.longitude - p2.longitude)
        let distance = sqrt(a + b)
        let adis = (distance / 2.0) / tan(angle / 2.0 * M_PI / 180)

        let lng = adis * cos((90 - btpAngle) * M_PI / 180)
        let lat = adis * sin((90 - btpAngle) * M_PI / 180)
        return CLLocationCoordinate2D(latitude: center.latitude + lat, longitude: center.longitude + lng)
    }