iOS get angle of face up orientation

Question

When loading a screen in FaceUp Orientation I need to know the angle of the iPhone.

The iPhone is flat on the table but I just need to know if it is in vertical or horizontal position.

I can't use StatusBarOrientation since I have fixed orientation. The orientation of the status bar is always the same

Answer 1

This may be a good time to use CoreMotion. Looks like reading CoreMotionRate may give you what you want:

From the docs:

/*
 *  CMRotationRate
 *  
 *  Discussion:
 *    A structure containing 3-axis rotation rate data.
 *
 *  Fields:
 *    x:
 *      X-axis rotation rate in radians/second. The sign follows the right hand 
 *      rule (i.e. if the right hand is wrapped around the X axis such that the 
 *      tip of the thumb points toward positive X, a positive rotation is one 
 *      toward the tips of the other 4 fingers).
 *    y:
 *      Y-axis rotation rate in radians/second. The sign follows the right hand 
 *      rule (i.e. if the right hand is wrapped around the Y axis such that the 
 *      tip of the thumb points toward positive Y, a positive rotation is one 
 *      toward the tips of the other 4 fingers).
 *      z:
 *          Z-axis rotation rate in radians/second. The sign follows the right hand 
 *      rule (i.e. if the right hand is wrapped around the Z axis such that the 
 *      tip of the thumb points toward positive Z, a positive rotation is one 
 *      toward the tips of the other 4 fingers).
 */

Quick example of how to get these values:

private lazy var motionManager: CMMotionManager = {
    return CMMotionManager()
}()

func recordMotion() {
   motionManager.startDeviceMotionUpdatesToQueue(opQueue, withHandler: { (deviceMotion, error) in
            if let motion = deviceMotion {
                 print(motion.rotationRate.x)
                 print(motion.rotationRate.y)
                 print(motion.rotationRate.z)
            }
        })
}