[feat] add configurable landscape entry for mobile sessions

apps/ios/CrossDeskMobile/ContentView.swift

@@ -75,7 +75,7 @@ struct ContentView: View {
         }
         .onAppear {
             if !session.sessionVisible {
-                AppOrientation.update(to: .portrait)
+                AppOrientation.endSession()
             }
             if scenePhase == .active {
                 session.applicationDidBecomeActive()
@@ -840,6 +840,11 @@ private struct ServerSettingsView: View {
                 }
                 .pickerStyle(.segmented)
             }
+            Section {
+                Toggle("连接后自动横屏", isOn: $session.autoLandscape)
+            } header: {
+                Text("屏幕方向")
+            }
             Section {
                 DisclosureGroup(isExpanded: $serverConfigurationExpanded) {
                     Toggle("使用自定义服务器", isOn: $usesCustomServer)

apps/ios/CrossDeskMobile/CrossDeskMobileApp.swift

@@ -12,24 +12,88 @@ final class CrossDeskAppDelegate: NSObject, UIApplicationDelegate {
     }
 }
 
+@MainActor
 enum AppOrientation {
-    static func update(to orientations: UIInterfaceOrientationMask) {
-        DispatchQueue.main.async {
-            // iPad windows can rotate and resize independently of the session.
-            // Keep all orientations available and let the window manager choose
-            // the geometry; the phone still locks the home screen to portrait.
-            guard UIDevice.current.userInterfaceIdiom != .pad else { return }
-            CrossDeskAppDelegate.supportedOrientations = orientations
+    nonisolated static let autoLandscapeKey = "crossdesk.mobile.auto-landscape"
+    private static var sessionActive = false
+    private static var waitingForLandscape = false
+    private static var deviceObserver: NSObjectProtocol?
 
-            for case let scene as UIWindowScene in UIApplication.shared.connectedScenes {
-                scene.windows.forEach {
-                    $0.rootViewController?.setNeedsUpdateOfSupportedInterfaceOrientations()
-                }
-                scene.requestGeometryUpdate(
-                    .iOS(interfaceOrientations: orientations)
-                ) { error in
-                    NSLog("CrossDesk orientation update failed: %@", error.localizedDescription)
-                }
+    nonisolated static func beginSession(autoLandscape: Bool) {
+        DispatchQueue.main.async { beginSessionOnMain(autoLandscape: autoLandscape) }
+    }
+
+    private static func beginSessionOnMain(autoLandscape: Bool) {
+        // Repeated transport-ready callbacks must not lock an existing session again.
+        guard !sessionActive else { return }
+        sessionActive = true
+        waitingForLandscape = autoLandscape && UIDevice.current.userInterfaceIdiom == .phone
+        if waitingForLandscape {
+            CrossDeskAppDelegate.supportedOrientations = .landscape
+            resumeObserving()
+        } else {
+            apply(to: .allButUpsideDown)
+        }
+    }
+
+    nonisolated static func endSession() {
+        DispatchQueue.main.async {
+            sessionActive = false
+            waitingForLandscape = false
+            stopObserving()
+            apply(to: .portrait)
+        }
+    }
+
+    nonisolated static func resume() {
+        DispatchQueue.main.async { resumeObserving() }
+    }
+
+    private static func resumeObserving() {
+        guard sessionActive, waitingForLandscape, deviceObserver == nil,
+              UIApplication.shared.applicationState == .active else { return }
+        apply(to: .landscape)
+        deviceObserver = NotificationCenter.default.addObserver(
+            forName: UIDevice.orientationDidChangeNotification, object: nil, queue: .main
+        ) { _ in
+            MainActor.assumeIsolated { deviceDidRotate() }
+        }
+        UIDevice.current.beginGeneratingDeviceOrientationNotifications()
+        deviceDidRotate()
+    }
+
+    nonisolated static func suspend() {
+        DispatchQueue.main.async { stopObserving() }
+    }
+
+    private static func stopObserving() {
+        guard let observer = deviceObserver else { return }
+        NotificationCenter.default.removeObserver(observer)
+        deviceObserver = nil
+        UIDevice.current.endGeneratingDeviceOrientationNotifications()
+    }
+
+    private static func deviceDidRotate() {
+        // UIDevice reports physical posture; window geometry also changes when
+        // we request landscape and must never release the initial lock itself.
+        guard sessionActive, waitingForLandscape, deviceObserver != nil,
+              UIApplication.shared.applicationState == .active,
+              UIDevice.current.orientation.isLandscape else { return }
+        waitingForLandscape = false
+        stopObserving()
+        apply(to: .allButUpsideDown)
+    }
+
+    private static func apply(to orientations: UIInterfaceOrientationMask) {
+        // iPad keeps every orientation available, including in resizable windows.
+        guard UIDevice.current.userInterfaceIdiom != .pad else { return }
+        CrossDeskAppDelegate.supportedOrientations = orientations
+        for case let scene as UIWindowScene in UIApplication.shared.connectedScenes {
+            scene.windows.forEach {
+                $0.rootViewController?.setNeedsUpdateOfSupportedInterfaceOrientations()
+            }
+            scene.requestGeometryUpdate(.iOS(interfaceOrientations: orientations)) { error in
+                NSLog("CrossDesk orientation update failed: %@", error.localizedDescription)
             }
         }
     }

apps/ios/CrossDeskMobile/RemoteSessionModel.swift

@@ -312,6 +312,9 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe
     @Published var videoAdaptationPolicy = VideoAdaptationPolicy.saved {
         didSet { videoAdaptationPolicy.save() }
     }
+    @Published var autoLandscape = UserDefaults.standard.object(forKey: AppOrientation.autoLandscapeKey) as? Bool ?? true {
+        didSet { UserDefaults.standard.set(autoLandscape, forKey: AppOrientation.autoLandscapeKey) }
+    }
     @Published private(set) var videoSettings = RemoteVideoSettingsState()
     @Published var remoteID = ""
     @Published var password = ""
@@ -437,6 +440,7 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe
 
     func applicationDidBecomeActive() {
         appIsActive = true
+        AppOrientation.resume()
         pictureInPicture.didBecomeActive()
         appUpdates.setEnabled(hasNetworkConsent)
         privacyNotice.didBecomeActive(hasNetworkConsent: hasNetworkConsent)
@@ -447,6 +451,7 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe
 
     func applicationDidEnterBackground() {
         appIsActive = false
+        AppOrientation.suspend()
         appUpdates.setEnabled(false)
         privacyNotice.didEnterBackground()
         suspendVideoForBackground()
@@ -591,6 +596,7 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe
     }
 
     private func beginRemoteConnection(_ identifier: String) {
+        AppOrientation.endSession()
         networkStatistics = RemoteNetworkStatistics()
         resetRemoteHostInfo()
         cancelVideoRecovery()
@@ -714,7 +720,7 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe
         selectedDisplay = 0
         connectionStatus = "未连接"
         audioPlayer.endSession()
-        AppOrientation.update(to: .portrait)
+        AppOrientation.endSession()
         appUpdates.checkNow()
     }
 
@@ -1191,7 +1197,7 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe
             recordSuccessfulConnectionIfNeeded()
             audioPlayer.setEnabled(audioEnabled)
             bridge.setAudioEnabled(audioEnabled)
-            AppOrientation.update(to: .allButUpsideDown)
+            AppOrientation.beginSession(autoLandscape: autoLandscape)
         case 2: connectionStatus = "正在收集 ICE 候选"
         case 3: finishConnection(withError: "网络连接已中断，请重新连接。")
         case 4:

apps/ios/README.md

@@ -203,6 +203,15 @@ the available space. Settings and reading pages are limited to 720 points.
 Resizing preserves the connection fields and active session. iPhone retains its
 portrait home screen and two-column recent-connection grid.
 
+On iPhone, Settings → Screen orientation (屏幕方向) → Landscape after connecting
+(连接后自动横屏) is enabled by default and saved locally. A new session starts in
+landscape and keeps that orientation until the phone is physically held sideways;
+it then resumes the existing device-following policy for the rest of the session.
+Portrait, flat and unknown device poses do not release the initial landscape hold.
+Turning the option off keeps the existing rotation behavior. Leaving the session
+restores portrait; foregrounding the same session does not reapply a released hold.
+iPad orientation and multitasking are unaffected.
+
 ## System keyboard and remote text
 
 The session keyboard button opens the iPhone/iPad's selected system keyboard.