Introduce Application.PlatformSettings

src/Avalonia.Base/Input/IInputRoot.cs

@@ -26,7 +26,7 @@ namespace Avalonia.Input
         /// Represents a contract for accessing platform-specific settings and information.
         /// </summary>
         /// <remarks>
-        /// Focus manager can be null only if window wasn't initialized yet.
+        /// PlatformSettings can be null only if window wasn't initialized yet.
         /// </remarks>
         IPlatformSettings? PlatformSettings { get; }
         

src/Avalonia.Controls/Application.cs

@@ -180,6 +180,17 @@ namespace Avalonia
         /// </summary>
         public IApplicationLifetime? ApplicationLifetime { get; set; }
 
+        /// <summary>
+        /// Represents a contract for accessing platform-specific settings and information.
+        /// </summary>
+        /// <remarks>
+        /// PlatformSettings can be null only if application wasn't initialized yet.
+        /// <see cref="TopLevel"/>'s <see cref="TopLevel.PlatformSettings"/> is an equivalent API
+        /// which should always be preferred over a global one,
+        /// as specific top levels might have different settings set-up. 
+        /// </remarks>
+        public IPlatformSettings? PlatformSettings => AvaloniaLocator.Current.GetService<IPlatformSettings>();
+        
         event Action<IReadOnlyList<IStyle>>? IGlobalStyles.GlobalStylesAdded
         {
             add => _stylesAdded += value;
@@ -229,10 +240,12 @@ namespace Avalonia
             var focusManager = new FocusManager();
             InputManager = new InputManager();
 
-            var settings = AvaloniaLocator.Current.GetRequiredService<IPlatformSettings>();
-            settings.ColorValuesChanged += OnColorValuesChanged;
-            OnColorValuesChanged(settings, settings.GetColorValues());
-            
+            if (PlatformSettings is { } settings)
+            {
+                settings.ColorValuesChanged += OnColorValuesChanged;
+                OnColorValuesChanged(settings, settings.GetColorValues());
+            }
+
             AvaloniaLocator.CurrentMutable
                 .Bind<IAccessKeyHandler>().ToTransient<AccessKeyHandler>()
                 .Bind<IGlobalDataTemplates>().ToConstant(this)
@@ -242,7 +255,7 @@ namespace Avalonia
                 .Bind<IInputManager>().ToConstant(InputManager)
                 .Bind<IKeyboardNavigationHandler>().ToTransient<KeyboardNavigationHandler>()
                 .Bind<IDragDropDevice>().ToConstant(DragDropDevice.Instance);
-            
+
             // TODO: Fix this, for now we keep this behavior since someone might be relying on it in 0.9.x
             if (AvaloniaLocator.Current.GetService<IPlatformDragSource>() == null)
                 AvaloniaLocator.CurrentMutable

src/Avalonia.Themes.Fluent/Accents/SystemAccentColors.cs

@@ -16,18 +16,12 @@ internal class SystemAccentColors : IResourceProvider
     public const string AccentLight2Key = "SystemAccentColorLight2";
     public const string AccentLight3Key = "SystemAccentColorLight3";
     
-    private static readonly Color s_defaultSystemAccentColor = Color.FromRgb(0, 120, 215); 
-    private readonly IPlatformSettings? _platformSettings;
+    private static readonly Color s_defaultSystemAccentColor = Color.FromRgb(0, 120, 215);
     private bool _invalidateColors = true;
     private Color _systemAccentColor;
     private Color _systemAccentColorDark1, _systemAccentColorDark2, _systemAccentColorDark3;
     private Color _systemAccentColorLight1, _systemAccentColorLight2, _systemAccentColorLight3;
 
-    public SystemAccentColors()
-    {
-        _platformSettings = AvaloniaLocator.Current.GetService<IPlatformSettings>();
-    }
-    
     public bool HasResources => true;
     public bool TryGetResource(object key, ThemeVariant? theme, out object? value)
     {
@@ -96,10 +90,12 @@ internal class SystemAccentColors : IResourceProvider
             Owner = owner;
             OwnerChanged?.Invoke(this, EventArgs.Empty);
 
-            if (_platformSettings is not null)
+            if (GetFromOwner(owner) is { } platformSettings)
             {
-                _platformSettings.ColorValuesChanged += PlatformSettingsOnColorValuesChanged;
+                platformSettings.ColorValuesChanged += PlatformSettingsOnColorValuesChanged;
             }
+
+            _invalidateColors = true;
         }
     }
 
@@ -110,10 +106,12 @@ internal class SystemAccentColors : IResourceProvider
             Owner = null;
             OwnerChanged?.Invoke(this, EventArgs.Empty);
             
-            if (_platformSettings is not null)
+            if (GetFromOwner(owner) is { } platformSettings)
             {
-                _platformSettings.ColorValuesChanged -= PlatformSettingsOnColorValuesChanged;
+                platformSettings.ColorValuesChanged -= PlatformSettingsOnColorValuesChanged;
             }
+
+            _invalidateColors = true;
         }
     }
 
@@ -122,13 +120,25 @@ internal class SystemAccentColors : IResourceProvider
         if (_invalidateColors)
         {
             _invalidateColors = false;
+
+            var platformSettings = GetFromOwner(Owner);
             
-            _systemAccentColor = _platformSettings?.GetColorValues().AccentColor1 ?? s_defaultSystemAccentColor;
+            _systemAccentColor = platformSettings?.GetColorValues().AccentColor1 ?? s_defaultSystemAccentColor;
             (_systemAccentColorDark1,_systemAccentColorDark2, _systemAccentColorDark3,
                     _systemAccentColorLight1, _systemAccentColorLight2, _systemAccentColorLight3) = CalculateAccentShades(_systemAccentColor);
         }
     }
 
+    private static IPlatformSettings? GetFromOwner(IResourceHost? owner)
+    {
+        return owner switch
+        {
+            Application app => app.PlatformSettings,
+            Visual visual => TopLevel.GetTopLevel(visual)?.PlatformSettings,
+            _ => null
+        };
+    }
+    
     public static (Color d1, Color d2, Color d3, Color l1, Color l2, Color l3) CalculateAccentShades(Color accentColor)
     {
         // dark1step = (hslAccent.L - SystemAccentColorDark1.L) * 255