[GUI] add custom top-bar across al platforms (#682)

src/SharpEmu.GUI/App.axaml

@@ -25,6 +25,7 @@ cascade order so individual launcher views do not redefine global visuals.
     <StyleInclude Source="avares://SharpEmu.GUI/Themes/Styles/Base.axaml" />
     <StyleInclude Source="avares://SharpEmu.GUI/Themes/Styles/Surfaces.axaml" />
     <StyleInclude Source="avares://SharpEmu.GUI/Themes/Styles/Buttons.axaml" />
+    <StyleInclude Source="avares://SharpEmu.GUI/Themes/Styles/Chrome.axaml" />
     <StyleInclude Source="avares://SharpEmu.GUI/Themes/Styles/Inputs.axaml" />
     <StyleInclude Source="avares://SharpEmu.GUI/Themes/Styles/Console.axaml" />
     <StyleInclude Source="avares://SharpEmu.GUI/Themes/Styles/Library.axaml" />

src/SharpEmu.GUI/MainWindow.axaml

@@ -14,9 +14,7 @@ SPDX-License-Identifier: GPL-2.0-or-later
         WindowState="Maximized"
         WindowStartupLocation="CenterScreen"
         Background="{StaticResource BgBrush}"
-        ExtendClientAreaToDecorationsHint="True"
+        WindowDecorations="None"
-        WindowDecorations="Full"
-        ExtendClientAreaTitleBarHeightHint="44"
         Icon="avares://SharpEmu.GUI/Assets/SharpEmu.ico"
         KeyDown="OnKeyDown">
 
@@ -46,7 +44,11 @@ SPDX-License-Identifier: GPL-2.0-or-later
 
     <!-- Title bar; hidden in fullscreen (F11) along with the status bar, so
          the game gets the whole screen. -->
-    <Grid x:Name="TitleBar" Grid.Row="0" Height="44" Background="{StaticResource ChromeBrush}">
+    <Grid x:Name="TitleBar"
+          Grid.Row="0"
+          Height="44"
+          ColumnDefinitions="*,Auto"
+          Background="{StaticResource ChromeBrush}">
       <StackPanel Orientation="Horizontal" Spacing="10" Margin="16,0" VerticalAlignment="Center">
         <Image Source="avares://SharpEmu.GUI/Assets/SharpEmu.ico" Width="20" Height="20"
                RenderOptions.BitmapInterpolationMode="HighQuality" />
@@ -55,6 +57,29 @@ SPDX-License-Identifier: GPL-2.0-or-later
           <TextBlock x:Name="VersionText" Text="v0.0.1" FontSize="11" Foreground="{StaticResource MutedBrush}" />
         </Border>
       </StackPanel>
+      <StackPanel x:Name="WindowChromeButtons"
+                  Grid.Column="1"
+                  Orientation="Horizontal"
+                  HorizontalAlignment="Right">
+        <Button x:Name="MinimizeButton"
+                Classes="windowChrome"
+                ToolTip.Tip="Minimize"
+                AutomationProperties.Name="Minimize window">
+          <TextBlock Text="—" FontSize="16" />
+        </Button>
+        <Button x:Name="MaximizeButton"
+                Classes="windowChrome"
+                ToolTip.Tip="Restore"
+                AutomationProperties.Name="Restore window">
+          <TextBlock x:Name="MaximizeGlyph" Text="❐" FontSize="13" />
+        </Button>
+        <Button x:Name="CloseButton"
+                Classes="windowChrome windowClose"
+                ToolTip.Tip="Close"
+                AutomationProperties.Name="Close window">
+          <TextBlock Text="×" FontSize="20" />
+        </Button>
+      </StackPanel>
     </Grid>
 
     <!-- Main content -->
@@ -662,5 +687,73 @@ SPDX-License-Identifier: GPL-2.0-or-later
       <TextBlock x:Name="StatusBarRight" Grid.Column="1" Text="" FontSize="11"
                  Foreground="{StaticResource FaintBrush}" VerticalAlignment="Center" Margin="16,0" />
     </Grid>
+
+    <!-- Portable resize hit targets for the frameless desktop window. They
+         are disabled while maximized or fullscreen in code-behind. -->
+    <Panel x:Name="ResizeHandles"
+           Grid.RowSpan="3"
+           ZIndex="1000"
+           IsVisible="False">
+      <Border Tag="North"
+              Height="6"
+              HorizontalAlignment="Stretch"
+              VerticalAlignment="Top"
+              Background="#01000000"
+              Cursor="TopSide"
+              PointerPressed="OnResizeHandlePointerPressed" />
+      <Border Tag="South"
+              Height="6"
+              HorizontalAlignment="Stretch"
+              VerticalAlignment="Bottom"
+              Background="#01000000"
+              Cursor="BottomSide"
+              PointerPressed="OnResizeHandlePointerPressed" />
+      <Border Tag="West"
+              Width="6"
+              HorizontalAlignment="Left"
+              VerticalAlignment="Stretch"
+              Background="#01000000"
+              Cursor="LeftSide"
+              PointerPressed="OnResizeHandlePointerPressed" />
+      <Border Tag="East"
+              Width="6"
+              HorizontalAlignment="Right"
+              VerticalAlignment="Stretch"
+              Background="#01000000"
+              Cursor="RightSide"
+              PointerPressed="OnResizeHandlePointerPressed" />
+      <Border Tag="NorthWest"
+              Width="12"
+              Height="12"
+              HorizontalAlignment="Left"
+              VerticalAlignment="Top"
+              Background="#01000000"
+              Cursor="TopLeftCorner"
+              PointerPressed="OnResizeHandlePointerPressed" />
+      <Border Tag="NorthEast"
+              Width="12"
+              Height="12"
+              HorizontalAlignment="Right"
+              VerticalAlignment="Top"
+              Background="#01000000"
+              Cursor="TopRightCorner"
+              PointerPressed="OnResizeHandlePointerPressed" />
+      <Border Tag="SouthWest"
+              Width="12"
+              Height="12"
+              HorizontalAlignment="Left"
+              VerticalAlignment="Bottom"
+              Background="#01000000"
+              Cursor="BottomLeftCorner"
+              PointerPressed="OnResizeHandlePointerPressed" />
+      <Border Tag="SouthEast"
+              Width="12"
+              Height="12"
+              HorizontalAlignment="Right"
+              VerticalAlignment="Bottom"
+              Background="#01000000"
+              Cursor="BottomRightCorner"
+              PointerPressed="OnResizeHandlePointerPressed" />
+    </Panel>
   </Grid>
 </Window>

src/SharpEmu.GUI/MainWindow.axaml.cs

@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 using Avalonia;
+using Avalonia.Automation;
 using Avalonia.Collections;
 using Avalonia.Controls;
 using Avalonia.Input;
@@ -164,6 +165,22 @@ public partial class MainWindow : Window
         };
 
         TitleBar.PointerPressed += OnTitleBarPointerPressed;
+        TitleBar.DoubleTapped += OnTitleBarDoubleTapped;
+        MinimizeButton.Click += (_, _) => WindowState = WindowState.Minimized;
+        MaximizeButton.Click += (_, _) => ToggleMaximized();
+        CloseButton.Click += (_, _) => Close();
+        Opened += (_, _) =>
+        {
+            // Some compositors ignore the initial maximized state while a
+            // frameless native window is still being created.
+            if (WindowState == WindowState.Normal)
+            {
+                WindowState = WindowState.Maximized;
+            }
+
+            UpdateWindowChromeState();
+        };
+        UpdateWindowChromeState();
         GameList.SelectionChanged += (_, _) => UpdateSelectedGame();
         GameList.DoubleTapped += (_, _) => LaunchSelected();
         SearchBox.TextChanged += (_, _) => RefreshVisibleGames();
@@ -813,12 +830,81 @@ public partial class MainWindow : Window
 
     private void OnTitleBarPointerPressed(object? sender, PointerPressedEventArgs e)
     {
-        if (e.GetCurrentPoint(this).Properties.IsLeftButtonPressed)
+        if (e.Source is Visual source &&
+            source.FindAncestorOfType<Button>(includeSelf: true) is null &&
+            e.GetCurrentPoint(this).Properties.IsLeftButtonPressed)
         {
             BeginMoveDrag(e);
         }
     }
 
+    private void OnTitleBarDoubleTapped(object? sender, TappedEventArgs e)
+    {
+        if (e.Source is Visual source &&
+            source.FindAncestorOfType<Button>(includeSelf: true) is null)
+        {
+            ToggleMaximized();
+            e.Handled = true;
+        }
+    }
+
+    private void ToggleMaximized()
+    {
+        WindowState = WindowState == WindowState.Maximized
+            ? WindowState.Normal
+            : WindowState.Maximized;
+    }
+
+    private void UpdateMaximizeButton()
+    {
+        if (MaximizeGlyph is not { } glyph || MaximizeButton is not { } button)
+        {
+            return;
+        }
+
+        var isMaximized = WindowState == WindowState.Maximized;
+        glyph.Text = isMaximized ? "❐" : "□";
+        ToolTip.SetTip(button, isMaximized ? "Restore" : "Maximize");
+        AutomationProperties.SetName(
+            button,
+            isMaximized ? "Restore window" : "Maximize window");
+    }
+
+    private void UpdateWindowChromeState()
+    {
+        UpdateMaximizeButton();
+        var isFullscreen = WindowState == WindowState.FullScreen;
+
+        if (TitleBar is { } titleBar)
+        {
+            titleBar.IsVisible = !isFullscreen;
+        }
+
+        if (StatusBar is { } statusBar)
+        {
+            statusBar.IsVisible = !isFullscreen;
+        }
+
+        if (ResizeHandles is { } handles)
+        {
+            handles.IsVisible = CanResize && WindowState == WindowState.Normal;
+        }
+    }
+
+    private void OnResizeHandlePointerPressed(object? sender, PointerPressedEventArgs e)
+    {
+        if (WindowState != WindowState.Normal ||
+            !e.GetCurrentPoint(this).Properties.IsLeftButtonPressed ||
+            sender is not Control { Tag: string edgeName } ||
+            !Enum.TryParse<WindowEdge>(edgeName, out var edge))
+        {
+            return;
+        }
+
+        BeginResizeDrag(edge, e);
+        e.Handled = true;
+    }
+
     // ---- Settings ----
 
     private void ApplySettingsToControls()
@@ -1831,6 +1917,8 @@ public partial class MainWindow : Window
         base.OnPropertyChanged(change);
         if (change.Property == WindowStateProperty)
         {
+            UpdateWindowChromeState();
+
             // The XAML WindowState="Maximized" assignment raises this change
             // during InitializeComponent, before named controls are wired up.
             if (WindowState == WindowState.Minimized)

src/SharpEmu.GUI/Themes/Styles/Chrome.axaml

@@ -0,0 +1,30 @@
+<!--
+Copyright (C) 2026 SharpEmu Emulator Project
+SPDX-License-Identifier: GPL-2.0-or-later
+Window chrome button sizing and interaction states.
+-->
+
+<Styles xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+  <Style Selector="Button.windowChrome">
+    <Setter Property="Width" Value="46" />
+    <Setter Property="Height" Value="44" />
+    <Setter Property="MinWidth" Value="0" />
+    <Setter Property="MinHeight" Value="0" />
+    <Setter Property="Padding" Value="0" />
+    <Setter Property="CornerRadius" Value="0" />
+    <Setter Property="Background" Value="Transparent" />
+    <Setter Property="BorderThickness" Value="0" />
+    <Setter Property="Foreground" Value="{StaticResource TextBrush}" />
+    <Setter Property="HorizontalContentAlignment" Value="Center" />
+    <Setter Property="VerticalContentAlignment" Value="Center" />
+  </Style>
+  <Style Selector="Button.windowChrome:pointerover /template/ ContentPresenter#PART_ContentPresenter">
+    <Setter Property="Background" Value="{StaticResource ElevatedBrush}" />
+    <Setter Property="Foreground" Value="{StaticResource TextBrush}" />
+  </Style>
+  <Style Selector="Button.windowClose:pointerover /template/ ContentPresenter#PART_ContentPresenter">
+    <Setter Property="Background" Value="{StaticResource DangerBrush}" />
+    <Setter Property="Foreground" Value="White" />
+  </Style>
+</Styles>