[GUI] few stability patches for GUI

src/SharpEmu.GUI/GameLibraryCache.cs

@@ -0,0 +1,168 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using System.Collections.Generic;
+using System.IO;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace SharpEmu.GUI;
+
+/// <summary>
+/// Remembers the last completed library scan so a cold start can paint the
+/// grid immediately instead of waiting on a recursive walk of every game
+/// folder. The cache is a display seed, never an authority: startup still
+/// runs the normal scan and reconciles over it, so a stale file can only
+/// ever cost one frame of wrong content, not a wrong library.
+/// </summary>
+internal static class GameLibraryCache
+{
+    private const int CurrentVersion = 1;
+
+    private static readonly JsonSerializerOptions SerializerOptions = new()
+    {
+        WriteIndented = true,
+        DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
+    };
+
+    internal static string CachePath =>
+        Path.Combine(AppContext.BaseDirectory, "user", "library_cache.json");
+
+    internal sealed class CachedGame
+    {
+        public string Name { get; set; } = string.Empty;
+        public string? TitleId { get; set; }
+        public string? Version { get; set; }
+        public string Path { get; set; } = string.Empty;
+        public long SizeBytes { get; set; }
+        public string? CoverPath { get; set; }
+        public string? BackgroundPath { get; set; }
+    }
+
+    internal sealed class CacheDocument
+    {
+        public int Version { get; set; }
+        public List<string> Folders { get; set; } = [];
+        public List<CachedGame> Games { get; set; } = [];
+    }
+
+    /// <summary>
+    /// Returns the cached games when the file matches the configured folder
+    /// set and the executables still exist. Entries whose executable is gone
+    /// are dropped so a removed game never flashes on screen.
+    /// </summary>
+    internal static List<GameEntry> Load(IReadOnlyList<string> folders)
+    {
+        var games = new List<GameEntry>();
+        try
+        {
+            if (!File.Exists(CachePath))
+            {
+                return games;
+            }
+
+            var document = JsonSerializer.Deserialize<CacheDocument>(
+                File.ReadAllText(CachePath),
+                SerializerOptions);
+            if (document is null || document.Version != CurrentVersion)
+            {
+                return games;
+            }
+
+            if (!SameFolders(document.Folders, folders))
+            {
+                return games;
+            }
+
+            foreach (var cached in document.Games)
+            {
+                if (string.IsNullOrWhiteSpace(cached.Path) || !File.Exists(cached.Path))
+                {
+                    continue;
+                }
+
+                games.Add(new GameEntry(
+                    cached.Name,
+                    cached.TitleId,
+                    cached.Version,
+                    cached.Path,
+                    cached.SizeBytes,
+                    Existing(cached.CoverPath),
+                    Existing(cached.BackgroundPath)));
+            }
+        }
+        catch (Exception exception)
+        {
+            Console.Error.WriteLine(
+                $"[GUI][WARN] Could not read the library cache: {exception.Message}");
+            games.Clear();
+        }
+
+        return games;
+    }
+
+    internal static void Save(IReadOnlyList<string> folders, IReadOnlyList<GameEntry> games)
+    {
+        try
+        {
+            var directory = Path.GetDirectoryName(CachePath);
+            if (!string.IsNullOrEmpty(directory))
+            {
+                Directory.CreateDirectory(directory);
+            }
+
+            var document = new CacheDocument
+            {
+                Version = CurrentVersion,
+                Folders = [.. folders],
+            };
+
+            foreach (var game in games)
+            {
+                document.Games.Add(new CachedGame
+                {
+                    Name = game.Name,
+                    TitleId = game.TitleId,
+                    Version = game.Version,
+                    Path = game.Path,
+                    SizeBytes = game.SizeBytes,
+                    CoverPath = game.CoverPath,
+                    BackgroundPath = game.BackgroundPath,
+                });
+            }
+
+            File.WriteAllText(
+                CachePath,
+                JsonSerializer.Serialize(document, SerializerOptions));
+        }
+        catch (Exception exception)
+        {
+            Console.Error.WriteLine(
+                $"[GUI][WARN] Could not write the library cache: {exception.Message}");
+        }
+    }
+
+    private static string? Existing(string? path) =>
+        !string.IsNullOrWhiteSpace(path) && File.Exists(path) ? path : null;
+
+    private static bool SameFolders(
+        IReadOnlyList<string> cached,
+        IReadOnlyList<string> configured)
+    {
+        if (cached.Count != configured.Count)
+        {
+            return false;
+        }
+
+        var known = new HashSet<string>(cached, GameLibraryPath.Comparer);
+        foreach (var folder in configured)
+        {
+            if (!known.Contains(folder))
+            {
+                return false;
+            }
+        }
+
+        return true;
+    }
+}

src/SharpEmu.GUI/MainWindow.GameOptions.cs

@@ -86,6 +86,7 @@ public partial class MainWindow
             CloseGameSettings();
             LaunchSelected();
         };
+        GameOptionsCloseButton.Click += (_, _) => CloseGameSettings();
         GameOptionsOpenFolderButton.Click += (_, _) => OpenSelectedGameFolder();
         GameOptionsCopyPathButton.Click += async (_, _) =>
             await CopyToClipboardAsync((GameList.SelectedItem as GameEntry)?.Path);
@@ -140,6 +141,7 @@ public partial class MainWindow
             !string.IsNullOrWhiteSpace(game.TitleId);
 
         _isGameSettingsOpen = true;
+        SetGameOptionsPagesSpan(coversConsoleRow: true);
         SetGameOptionsOpenClass(BackdropLayer, active: true);
         SetGameOptionsOpenClass(CarouselHost, active: true);
         SetGameOptionsOpenClass(LibrarySelectedDetails, active: true);
@@ -158,6 +160,7 @@ public partial class MainWindow
         }
 
         _isGameSettingsOpen = false;
+        SetGameOptionsPagesSpan(coversConsoleRow: false);
         SetGameOptionsNavigationIndicator(_gameOptionsIndicatorIndex, animate: false);
         _gameSettingsTitleId = null;
         _gameEnvironmentPassthrough.Clear();
@@ -438,6 +441,11 @@ public partial class MainWindow
             animate);
     }
 
+    private void SetGameOptionsPagesSpan(bool coversConsoleRow)
+    {
+        Grid.SetRowSpan(PagesHost, coversConsoleRow ? 2 : 1);
+    }
+
     private Button[] GameOptionsNavigationButtons() =>
     [
         GameOptionsGeneralNav,

src/SharpEmu.GUI/MainWindow.axaml

@@ -154,7 +154,7 @@ SPDX-License-Identifier: GPL-2.0-or-later
         </StackPanel>
       </Grid>
 
-      <Panel Grid.Row="1" x:Name="PagesHost">
+      <Panel Grid.Row="1" x:Name="PagesHost" ZIndex="1">
 
         <!-- Library page. Covers use a horizontal virtualized rail so the
              number of realized images stays bounded for large libraries. -->
@@ -311,6 +311,7 @@ SPDX-License-Identifier: GPL-2.0-or-later
                                                Duration="0:0:0.18" />
               </Transitions>
             </StackPanel.Transitions>
+            <Border Classes="selectedDetailsDivider" />
             <TextBlock Classes="selectedGameTitle"
                        Text="{Binding Name}"
                        FontWeight="SemiBold"
@@ -449,7 +450,7 @@ SPDX-License-Identifier: GPL-2.0-or-later
               </Border>
 
               <Border Padding="260,18,32,24">
-                <Grid ColumnDefinitions="*,Auto"
+                <Grid ColumnDefinitions="*,Auto,Auto"
                       ColumnSpacing="34">
                   <StackPanel Spacing="3"
                               VerticalAlignment="Center">
@@ -500,6 +501,20 @@ SPDX-License-Identifier: GPL-2.0-or-later
                                  Text="{Binding TitleId}" />
                     </StackPanel>
                   </StackPanel>
+
+                  <Button x:Name="GameOptionsCloseButton"
+                          Grid.Column="2"
+                          Classes="optionsCircle compact"
+                          VerticalAlignment="Center"
+                          ToolTip.Tip="{Binding [Common.Back],
+                                                Source={x:Static local:Localization.Instance},
+                                                x:CompileBindings=False}"
+                          AutomationProperties.Name="{Binding [Common.Back],
+                                                              Source={x:Static local:Localization.Instance},
+                                                              x:CompileBindings=False}">
+                    <TextBlock Classes="materialSymbol"
+                               Text="close" />
+                  </Button>
                 </Grid>
               </Border>
 
@@ -511,10 +526,18 @@ SPDX-License-Identifier: GPL-2.0-or-later
                       RowDefinitions="Auto,*">
                   <Button x:Name="GameOptionsLaunchButton"
                           Classes="gameOptionsLaunch">
-                    <TextBlock VerticalAlignment="Center"
-                               Text="{Binding [Library.Context.Launch],
-                                              Source={x:Static local:Localization.Instance},
-                                              x:CompileBindings=False}" />
+                    <StackPanel Orientation="Horizontal"
+                                Spacing="8"
+                                HorizontalAlignment="Center"
+                                VerticalAlignment="Center">
+                      <TextBlock Classes="materialSymbol"
+                                 VerticalAlignment="Center"
+                                 Text="play_arrow" />
+                      <TextBlock VerticalAlignment="Center"
+                                 Text="{Binding [Library.Context.Launch],
+                                                Source={x:Static local:Localization.Instance},
+                                                x:CompileBindings=False}" />
+                    </StackPanel>
                   </Button>
 
                   <ScrollViewer x:Name="GameOptionsNavScroll"

src/SharpEmu.GUI/MainWindow.axaml.cs

@@ -36,7 +36,7 @@ public partial class MainWindow : Window
     private const int MaxConsoleLines = 4000;
     private const int MaxConsoleLinesPerFlush = 500;
     private static readonly TimeSpan NavigationIndicatorAnimationDuration =
-        TimeSpan.FromMilliseconds(240);
+        TimeSpan.FromMilliseconds(180);
 
     private static readonly IBrush DefaultLineBrush = new SolidColorBrush(Color.Parse("#C7CFDE"));
     private static readonly IBrush DimLineBrush = new SolidColorBrush(Color.Parse("#6B7488"));
@@ -555,7 +555,7 @@ public partial class MainWindow : Window
         translationAnimation.InsertExpressionKeyFrame(
             1f,
             "this.FinalValue",
-            new SineEaseInOut());
+            new CubicEaseOut());
 
         var animations = visual.Compositor.CreateImplicitAnimationCollection();
         animations[nameof(CompositionVisual.Translation)] = translationAnimation;
@@ -848,6 +848,8 @@ public partial class MainWindow : Window
         {
             _ = CheckForUpdatesAsync();
         }
+
+        SeedLibraryFromCache();
         await RescanLibraryAsync();
     }
 
@@ -1547,6 +1549,31 @@ public partial class MainWindow : Window
         }
     }
 
+    /// <summary>
+    /// Paints the previous scan's result before the real scan starts. The
+    /// scan that follows reconciles over this, so the cache only ever
+    /// shortens the blank period; it never decides what the library holds.
+    /// </summary>
+    private void SeedLibraryFromCache()
+    {
+        Dispatcher.UIThread.VerifyAccess();
+
+        if (_allGames.Count != 0)
+        {
+            return;
+        }
+
+        var cached = GameLibraryCache.Load(_settings.GameFolders.ToArray());
+        if (cached.Count == 0)
+        {
+            return;
+        }
+
+        _allGames.AddRange(cached);
+        RefreshVisibleGames(new HashSet<GameEntry>(cached));
+        LoadGameDetailsInBackground(cached, cached);
+    }
+
     private async Task RescanLibraryAsync(bool showProgress = true)
     {
         Dispatcher.UIThread.VerifyAccess();
@@ -1576,6 +1603,7 @@ public partial class MainWindow : Window
         LoadingState.IsVisible = false;
         LoadGameDetailsInBackground(reconciliation.CoversToLoad, reconciliation.Games);
         UpdateDiscordPresence();
+        GameLibraryCache.Save(folders, reconciliation.Games);
     }
 
     /// <summary>

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

@@ -103,6 +103,12 @@ Contextual per-game options reveal, actions, and selected-game motion.
     <Setter Property="Foreground" Value="White" />
   </Style>
 
+  <Style Selector="Button.optionsCircle.compact, ToggleButton.optionsCircle.compact">
+    <Setter Property="Width" Value="40" />
+    <Setter Property="Height" Value="40" />
+    <Setter Property="CornerRadius" Value="20" />
+  </Style>
+
   <Style Selector="StackPanel.selectedDetailsHost">
     <Setter Property="Spacing" Value="18" />
   </Style>
@@ -119,6 +125,21 @@ Contextual per-game options reveal, actions, and selected-game motion.
     <Setter Property="FontSize" Value="26" />
   </Style>
 
+  <Style Selector="Border.selectedDetailsDivider">
+    <Setter Property="Height" Value="1" />
+    <Setter Property="MinWidth" Value="440" />
+    <Setter Property="Margin" Value="0,0,0,18" />
+    <Setter Property="HorizontalAlignment" Value="Stretch" />
+    <Setter Property="Background">
+      <LinearGradientBrush StartPoint="0%,0%" EndPoint="100%,0%">
+        <GradientStop Offset="0" Color="#00FFFFFF" />
+        <GradientStop Offset="0.06" Color="#2EFFFFFF" />
+        <GradientStop Offset="0.55" Color="#14FFFFFF" />
+        <GradientStop Offset="1" Color="#00FFFFFF" />
+      </LinearGradientBrush>
+    </Setter>
+  </Style>
+
   <Style Selector="StackPanel.selectedDetailsHost.gridLayout Button.playButton">
     <Setter Property="MinHeight" Value="44" />
     <Setter Property="MinWidth" Value="168" />