videos: improve precision & sensitivity of auto-pause mechanism

Closes: https://github.com/damus-io/damus/pull/1308
Signed-off-by: William Casarin <jb55@jb55.com>

damus/damusApp.swift

@@ -20,11 +20,13 @@ struct damusApp: App {
 struct MainView: View {
     @State var needs_setup = false;
     @State var keypair: Keypair? = nil;
+    @StateObject private var orientationTracker = OrientationTracker()
     
     var body: some View {
         Group {
             if let kp = keypair, !needs_setup {
                 ContentView(keypair: kp)
+                    .environmentObject(orientationTracker)
             } else {
                 SetupView()
                     .onReceive(handle_notify(.login)) { notif in
@@ -38,7 +40,11 @@ struct MainView: View {
             try? clear_keypair()
             keypair = nil
         }
+        .onReceive(NotificationCenter.default.publisher(for: UIDevice.orientationDidChangeNotification)) { _ in
+            orientationTracker.setDeviceMajorAxis()
+        }
         .onAppear {
+            orientationTracker.setDeviceMajorAxis()
             keypair = get_saved_keypair()
         }
     }
@@ -65,3 +71,14 @@ class AppDelegate: NSObject, UIApplicationDelegate, UNUserNotificationCenterDele
         completionHandler()
     }
 }
+
+class OrientationTracker: ObservableObject {
+    var deviceMajorAxis: CGFloat = 0
+    func setDeviceMajorAxis() {
+        let bounds = UIScreen.main.bounds
+        let height = max(bounds.height, bounds.width) /// device's longest dimension
+        let width = min(bounds.height, bounds.width)  /// device's shortest dimension
+        let orientation = UIDevice.current.orientation
+        deviceMajorAxis = (orientation == .portrait || orientation == .unknown) ? height : width
+    }
+}