swift - 创建指向指定位置方向的自定义罗盘箭头

Question

基本上我想要一个旋转的箭头图像，以便将用户引导到附近的位置。我正在使用核心位置航向数据来获取方向信息，相关代码如下。

 func locationManager(_ manager: CLLocationManager, didUpdateHeading newHeading: CLHeading) {
    print("MAGNETIC HEADING: \(newHeading.magneticHeading)")
    print("TRUE HEADING  \(newHeading.trueHeading)")

    var degrees = newHeading.trueHeading
    //Rotate the arrow image
    if self.arrowImageView != nil {

        self.arrowImageView.transform = CGAffineTransform(rotationAngle: CGFloat(degrees * (180.0 / M_PI)))
    }


}

我不确定这是否是正确的方法。

Answer 1

我设法使用此处找到的 C# 解决方案解决了这个问题 How to rotate a Direction Arrow to particular location

func UpdateCompass(origin: CLLocationCoordinate2D,target:CLLocationCoordinate2D, heading: CLHeading)
{
    var angle1 = GetAngleBetweenPoints(origin: origin, target: target);
    var angle2 = GetAngleFromHeading(heading: heading);
    var radian = .pi * (angle1 + angle2) / 180.0;
    let res =  radiansToDegrees(radians:radian)
    self.arrowImageView.transform = CGAffineTransform(rotationAngle: CGFloat(radian))
    //self.CompassImageView.transform = CGAffineTransform(rotationAngle: CGFloat(radian))
    UIView.animate(withDuration: 0.5, animations: {
       self.CompassImageView.transform = CGAffineTransform(rotationAngle: CGFloat(radian))
    })
}

func GetAngleBetweenPoints(origin:CLLocationCoordinate2D,target: CLLocationCoordinate2D) -> Double
{
var n = 270 - (atan2(origin.latitude - target.latitude, origin.longitude - target.longitude)) * 180 / .pi;
return n.truncatingRemainder(dividingBy: 360);
}

func GetAngleFromHeading(heading:CLHeading) -> Double
{
var radians = -heading.magneticHeading / 180.0 * .pi;
return radians * (180.0 / .pi);
}