Orientation improvements

iOS/AppDelegate.swift

@@ -19,6 +19,8 @@ final class AppDelegate: UIResponder, UIApplicationDelegate {
             UITabBar.appearance().backgroundImage = UIImage()
             UITabBar.appearance().isTranslucent = true
             UITabBar.appearance().backgroundColor = .clear
+
+            OrientationTracker.shared.startDeviceOrientationTracking()
         #endif
         return true
     }

iOS/Orientation.swift

@@ -21,11 +21,16 @@ struct Orientation {
     static func lockOrientation(_ orientation: UIInterfaceOrientationMask, andRotateTo rotateOrientation: UIInterfaceOrientation? = nil) {
         lockOrientation(orientation)
 
-        guard !rotateOrientation.isNil else {
+        guard let rotateOrientation = rotateOrientation else {
             return
         }
 
-        UIDevice.current.setValue(rotateOrientation!.rawValue, forKey: "orientation")
+        let orientationString = rotateOrientation == .portrait ? "portrait" : rotateOrientation == .landscapeLeft ? "landscapeLeft" :
+            rotateOrientation == .landscapeRight ? "landscapeRight" : rotateOrientation == .portraitUpsideDown ? "portraitUpsideDown" : "allButUpsideDown"
+
+        logger.info("rotating to \(orientationString)")
+
+        UIDevice.current.setValue(rotateOrientation.rawValue, forKey: "orientation")
         UINavigationController.attemptRotationToDeviceOrientation()
     }
 }

iOS/OrientationTracker.swift

@@ -0,0 +1,92 @@
+import CoreMotion
+import UIKit
+
+public class OrientationTracker {
+    public static let shared = OrientationTracker()
+
+    public static let deviceOrientationChangedNotification = NSNotification.Name("DeviceOrientationChangedNotification")
+
+    public var currentDeviceOrientation: UIDeviceOrientation = .portrait
+
+    public var currentInterfaceOrientation: UIInterfaceOrientation {
+        switch currentDeviceOrientation {
+        case .landscapeLeft:
+            return .landscapeLeft
+        case .landscapeRight:
+            return .landscapeRight
+        default:
+            return .portrait
+        }
+    }
+
+    public var currentInterfaceOrientationMask: UIInterfaceOrientationMask {
+        switch currentInterfaceOrientation {
+        case .landscapeLeft:
+            return .landscapeLeft
+        case .landscapeRight:
+            return .landscapeRight
+        default:
+            return .portrait
+        }
+    }
+
+    public var affineTransform: CGAffineTransform {
+        var angleRadians: Double
+        switch currentDeviceOrientation {
+        case .portrait:
+            angleRadians = 0
+        case .landscapeLeft:
+            angleRadians = -0.5 * .pi
+        case .landscapeRight:
+            angleRadians = 0.5 * .pi
+        case .portraitUpsideDown:
+            angleRadians = .pi
+        default:
+            return .identity
+        }
+        return CGAffineTransform(rotationAngle: angleRadians)
+    }
+
+    private let motionManager: CMMotionManager
+    private let queue: OperationQueue
+
+    private init() {
+        motionManager = CMMotionManager()
+        motionManager.accelerometerUpdateInterval = 0.1
+        queue = OperationQueue()
+    }
+
+    public func startDeviceOrientationTracking() {
+        motionManager.startAccelerometerUpdates(to: queue) { accelerometerData, error in
+            guard error == nil else { return }
+            guard let accelerometerData = accelerometerData else { return }
+
+            let newDeviceOrientation = self.deviceOrientation(forAccelerometerData: accelerometerData)
+            guard newDeviceOrientation != self.currentDeviceOrientation else { return }
+            self.currentDeviceOrientation = newDeviceOrientation
+
+            NotificationCenter.default.post(name: Self.deviceOrientationChangedNotification,
+                                            object: nil,
+                                            userInfo: nil)
+        }
+    }
+
+    public func stopDeviceOrientationTracking() {
+        motionManager.stopAccelerometerUpdates()
+    }
+
+    private func deviceOrientation(forAccelerometerData accelerometerData: CMAccelerometerData) -> UIDeviceOrientation {
+        let treshold = 0.55
+        if accelerometerData.acceleration.x >= treshold {
+            return .landscapeLeft
+        } else if accelerometerData.acceleration.x <= -treshold {
+            return .landscapeRight
+        } else if accelerometerData.acceleration.y <= -treshold {
+            return .portrait
+        } else if accelerometerData.acceleration.y >= treshold {
+            return .portraitUpsideDown
+        } else {
+            return currentDeviceOrientation
+        }
+    }
+}