feat(ui): fullscreen camera view on mobile landscape rotation

src/OpenIPC.Viewer.App/ViewModels/MainWindowViewModel.cs

@@ -33,6 +33,14 @@ public sealed partial class MainWindowViewModel : ViewModelBase, IRecipient<Open
     [NotifyPropertyChangedFor(nameof(IsSettingsSelected))]
     private ViewModelBase _currentPage;
 
+    // Orientation-driven fullscreen (mobile only). MainView reports whether
+    // the viewport is in mobile landscape; fullscreen engages only while the
+    // single-camera page is open, so list/settings pages keep their chrome.
+    private bool _isMobileLandscape;
+
+    [ObservableProperty]
+    private bool _isFullscreen;
+
     public bool IsLiveSelected => CurrentPage is GridPageViewModel;
     public bool IsLibrarySelected => CurrentPage is CameraLibraryPageViewModel or SingleCameraPageViewModel;
     public bool IsRecordingsSelected => CurrentPage is RecordingsPageViewModel;
@@ -71,6 +79,26 @@ public MainWindowViewModel(
         OverlayDialogPresenter.ActiveChanged += () => NavigateCommand.NotifyCanExecuteChanged();
     }
 
+    public void SetViewportOrientation(bool isMobileLandscape)
+    {
+        if (_isMobileLandscape == isMobileLandscape)
+            return;
+        _isMobileLandscape = isMobileLandscape;
+        UpdateFullscreen();
+    }
+
+    partial void OnCurrentPageChanged(ViewModelBase value) => UpdateFullscreen();
+
+    private void UpdateFullscreen()
+    {
+        IsFullscreen = _isMobileLandscape && CurrentPage is SingleCameraPageViewModel;
+        // Camera-to-camera swipe replaces the page VM while IsFullscreen stays
+        // true, so the flag is pushed to the current page explicitly instead
+        // of relying on the property-changed callback.
+        if (CurrentPage is SingleCameraPageViewModel camera)
+            camera.IsFullscreen = IsFullscreen;
+    }
+
     private static bool CanNavigate() => !OverlayDialogPresenter.IsAnyOpen;
 
     [RelayCommand(CanExecute = nameof(CanNavigate))]

src/OpenIPC.Viewer.App/ViewModels/SingleCameraPageViewModel.cs

@@ -68,6 +68,11 @@ public sealed partial class SingleCameraPageViewModel : ViewModelBase, IAsyncDis
     public bool IsConnecting =>
         Session is not null && State is SessionState.Connecting or SessionState.Reconnecting;
     public bool IsFailed => State == SessionState.Failed;
+    // Set by MainWindowViewModel while the device is in mobile landscape —
+    // hides the header / Majestic panel / bottom bar so the video gets the
+    // whole screen. Overlays (LIVE badge, telemetry, PTZ) stay on the video.
+    [ObservableProperty] private bool _isFullscreen;
+
     [ObservableProperty] private string? _snapshotPath;
     [ObservableProperty] private PtzController? _ptz;
     [ObservableProperty] private string _newPresetName = "";

src/OpenIPC.Viewer.App/Views/MainView.axaml

@@ -15,7 +15,9 @@
     Responsive layout. The split happens at 700px:
       wide  → desktop sidebar on the left, content fills the rest
       narrow → bottom-nav under the content (mobile / pinned-narrow window)
-    IsWideLayout is updated by code-behind on every SizeChanged.
+    ShowSidebar / ShowBottomNav are updated by code-behind on every SizeChanged
+    and both collapse while the mobile landscape-fullscreen camera view is
+    active (MainWindowViewModel.IsFullscreen).
 
     CurrentPage is hosted in a SINGLE ContentControl shared by both layouts.
     Hosting it twice (one ContentControl per layout) made the same page VM bind
@@ -29,7 +31,7 @@
     <!-- Desktop sidebar — fixed 200px wide; collapses to nothing when narrow. -->
     <Border Grid.Column="0"
             Width="200"
-            IsVisible="{Binding #Root.IsWideLayout}"
+            IsVisible="{Binding #Root.ShowSidebar}"
             Background="{StaticResource Bg2Brush}"
             BorderBrush="{StaticResource BorderWeakBrush}"
             BorderThickness="0,0,1,0">
@@ -96,7 +98,7 @@
     <!-- Content host + bottom nav (narrow only). One ContentControl, period. -->
     <DockPanel Grid.Column="1" LastChildFill="True">
       <views:BottomNavBar DockPanel.Dock="Bottom"
-                          IsVisible="{Binding #Root.IsNarrowLayout}" />
+                          IsVisible="{Binding #Root.ShowBottomNav}" />
       <ContentControl Content="{Binding CurrentPage}"
                       Padding="{Binding #Root.ContentPadding}" />
     </DockPanel>

src/OpenIPC.Viewer.App/Views/MainView.axaml.cs

@@ -1,5 +1,8 @@
+using System;
+using System.ComponentModel;
 using Avalonia;
 using Avalonia.Controls;
+using OpenIPC.Viewer.App.ViewModels;
 
 namespace OpenIPC.Viewer.App.Views;
 
@@ -10,13 +13,18 @@ public partial class MainView : UserControl
     // windows) gets the bottom strip.
     private const double WideBreakpoint = 700;
 
-    public static readonly DirectProperty<MainView, bool> IsWideLayoutProperty =
+    // Orientation-driven fullscreen is mobile-only: on desktop a window that
+    // is wider than tall is just a window, not a rotated device.
+    private static readonly bool IsMobilePlatform =
+        OperatingSystem.IsAndroid() || OperatingSystem.IsIOS();
+
+    public static readonly DirectProperty<MainView, bool> ShowSidebarProperty =
         AvaloniaProperty.RegisterDirect<MainView, bool>(
-            nameof(IsWideLayout), o => o.IsWideLayout);
+            nameof(ShowSidebar), o => o.ShowSidebar);
 
-    public static readonly DirectProperty<MainView, bool> IsNarrowLayoutProperty =
+    public static readonly DirectProperty<MainView, bool> ShowBottomNavProperty =
         AvaloniaProperty.RegisterDirect<MainView, bool>(
-            nameof(IsNarrowLayout), o => o.IsNarrowLayout);
+            nameof(ShowBottomNav), o => o.ShowBottomNav);
 
     // Content inset differs by layout (desktop has more breathing room). Exposed
     // as a property because the single shared ContentControl can no longer pick
@@ -29,41 +37,83 @@ public partial class MainView : UserControl
     private static readonly Thickness NarrowPadding = new(12);
 
     private bool _isWideLayout = true;
+    private bool _isFullscreen;
+    private bool _showSidebar = true;
+    private bool _showBottomNav;
     private Thickness _contentPadding = WidePadding;
+    private MainWindowViewModel? _vm;
 
-    public bool IsWideLayout
-    {
-        get => _isWideLayout;
-        private set
-        {
-            if (SetAndRaise(IsWideLayoutProperty, ref _isWideLayout, value))
-            {
-                RaisePropertyChanged(IsNarrowLayoutProperty, !value, value == false);
-                ContentPadding = value ? WidePadding : NarrowPadding;
-            }
-        }
-    }
-
-    public bool IsNarrowLayout => !_isWideLayout;
-
-    public Thickness ContentPadding
-    {
-        get => _contentPadding;
-        private set => SetAndRaise(ContentPaddingProperty, ref _contentPadding, value);
-    }
+    public bool ShowSidebar => _showSidebar;
+    public bool ShowBottomNav => _showBottomNav;
+    public Thickness ContentPadding => _contentPadding;
 
     public MainView()
     {
         InitializeComponent();
+        DataContextChanged += OnDataContextChanged;
         // Seed off the initial bounds — XAML evaluates IsVisible before
         // the first SizeChanged fires, so without this both layouts could
         // flash for a frame on narrow viewports.
-        IsWideLayout = Bounds.Width >= WideBreakpoint;
+        _isWideLayout = Bounds.Width >= WideBreakpoint;
+        UpdateChrome();
     }
 
     protected override void OnSizeChanged(SizeChangedEventArgs e)
     {
         base.OnSizeChanged(e);
-        IsWideLayout = e.NewSize.Width >= WideBreakpoint;
+        _isWideLayout = e.NewSize.Width >= WideBreakpoint;
+        // Landscape on a phone = the user rotated the device. The VM decides
+        // whether that means fullscreen (only while a camera page is open).
+        if (IsMobilePlatform)
+            _vm?.SetViewportOrientation(e.NewSize.Width > e.NewSize.Height);
+        UpdateChrome();
+    }
+
+    private void OnDataContextChanged(object? sender, EventArgs e)
+    {
+        if (_vm is not null)
+            _vm.PropertyChanged -= OnVmPropertyChanged;
+        _vm = DataContext as MainWindowViewModel;
+        if (_vm is not null)
+        {
+            _vm.PropertyChanged += OnVmPropertyChanged;
+            // Push current orientation in case the device started in landscape
+            // and SizeChanged fired before the DataContext was assigned.
+            if (IsMobilePlatform && Bounds.Width > 0)
+                _vm.SetViewportOrientation(Bounds.Width > Bounds.Height);
+        }
+        SetFullscreen(_vm?.IsFullscreen ?? false);
+    }
+
+    private void OnVmPropertyChanged(object? sender, PropertyChangedEventArgs e)
+    {
+        if (e.PropertyName == nameof(MainWindowViewModel.IsFullscreen) && _vm is not null)
+            SetFullscreen(_vm.IsFullscreen);
+    }
+
+    private void SetFullscreen(bool on)
+    {
+        if (_isFullscreen == on)
+            return;
+        _isFullscreen = on;
+        UpdateChrome();
+
+        // System status/navigation bars follow the app chrome on mobile;
+        // InsetsManager is null on desktop so this is a no-op there.
+        var insets = TopLevel.GetTopLevel(this)?.InsetsManager;
+        if (insets is not null)
+            insets.IsSystemBarVisible = !on;
+    }
+
+    private void UpdateChrome()
+    {
+        var showSidebar = _isWideLayout && !_isFullscreen;
+        var showBottomNav = !_isWideLayout && !_isFullscreen;
+        var padding = _isFullscreen ? new Thickness(0)
+            : _isWideLayout ? WidePadding : NarrowPadding;
+
+        SetAndRaise(ShowSidebarProperty, ref _showSidebar, showSidebar);
+        SetAndRaise(ShowBottomNavProperty, ref _showBottomNav, showBottomNav);
+        SetAndRaise(ContentPaddingProperty, ref _contentPadding, padding);
     }
 }

src/OpenIPC.Viewer.App/Views/Pages/SingleCameraPage.axaml

@@ -9,8 +9,9 @@
 
   <Grid RowDefinitions="Auto,*,Auto,Auto">
 
-    <!-- Header -->
-    <Grid Grid.Row="0" ColumnDefinitions="Auto,*,Auto" Margin="0,0,0,12">
+    <!-- Header. Hidden in landscape fullscreen — only the video row stays. -->
+    <Grid Grid.Row="0" ColumnDefinitions="Auto,*,Auto" Margin="0,0,0,12"
+          IsVisible="{Binding !IsFullscreen}">
       <Button Grid.Column="0"
               Content="{Binding [Common.Back], Source={x:Static svc:Localizer.Instance}}"
               Command="{Binding BackCommand}"
@@ -214,8 +215,13 @@
             Background="{StaticResource Bg2Brush}"
             BorderBrush="{StaticResource BorderWeakBrush}"
             BorderThickness="1"
-            CornerRadius="8"
-            IsVisible="{Binding IsMajestic}">
+            CornerRadius="8">
+      <Border.IsVisible>
+        <MultiBinding Converter="{x:Static BoolConverters.And}">
+          <Binding Path="IsMajestic" />
+          <Binding Path="!IsFullscreen" />
+        </MultiBinding>
+      </Border.IsVisible>
       <StackPanel Spacing="8">
 
         <!-- Title row -->
@@ -330,8 +336,9 @@
       </StackPanel>
     </Border>
 
-    <!-- Bottom bar -->
-    <Grid Grid.Row="3" ColumnDefinitions="Auto,*,Auto,Auto" Margin="0,12,0,0">
+    <!-- Bottom bar. Hidden in landscape fullscreen. -->
+    <Grid Grid.Row="3" ColumnDefinitions="Auto,*,Auto,Auto" Margin="0,12,0,0"
+          IsVisible="{Binding !IsFullscreen}">
 
       <!-- REC indicator (visible while recording) -->
       <Border Grid.Column="0"