Revert "Fluent2: use OS accent shades on Windows"

This reverts part of the commit 71bbc901a5.

src/Avalonia.Base/Platform/PlatformColorValues.cs

@@ -61,37 +61,6 @@ public record PlatformColorValues
         init => _accentColor3 = value;
     }
 
-    /// <summary>
-    /// Dark shade 1 of <see cref="AccentColor1"/>, when the platform provides one (Windows does).
-    /// Null when the platform only reports the base accent color; consumers are expected to compute a shade instead.
-    /// </summary>
-    public Color? AccentColorDark1 { get; init; }
-
-    /// <summary>
-    /// Dark shade 2 of <see cref="AccentColor1"/>, when the platform provides one. See <see cref="AccentColorDark1"/>.
-    /// </summary>
-    public Color? AccentColorDark2 { get; init; }
-
-    /// <summary>
-    /// Dark shade 3 of <see cref="AccentColor1"/>, when the platform provides one. See <see cref="AccentColorDark1"/>.
-    /// </summary>
-    public Color? AccentColorDark3 { get; init; }
-
-    /// <summary>
-    /// Light shade 1 of <see cref="AccentColor1"/>, when the platform provides one. See <see cref="AccentColorDark1"/>.
-    /// </summary>
-    public Color? AccentColorLight1 { get; init; }
-
-    /// <summary>
-    /// Light shade 2 of <see cref="AccentColor1"/>, when the platform provides one. See <see cref="AccentColorDark1"/>.
-    /// </summary>
-    public Color? AccentColorLight2 { get; init; }
-
-    /// <summary>
-    /// Light shade 3 of <see cref="AccentColor1"/>, when the platform provides one. See <see cref="AccentColorDark1"/>.
-    /// </summary>
-    public Color? AccentColorLight3 { get; init; }
-
     public PlatformColorValues()
     {
         AccentColor1 = DefaultAccent;

src/Avalonia.Themes.Fluent2/Accents/SystemAccentColors.cs

@@ -20,8 +20,7 @@ internal sealed class SystemAccentColors : ResourceProvider
     private static readonly Color s_defaultSystemAccentColor = Color.FromRgb(0, 120, 215);
     // Static shade values from WinUI (matching the Uno/WinUI SystemResources defaults). Used when
     // the platform provides no accent color, so the out-of-the-box palette matches WinUI exactly.
-    // When the platform reports the OS-computed shades (Windows does, via UISettings) those are
-    // used verbatim; otherwise an OS-provided base accent gets HSL-computed shades.
+    // OS-provided accent colors get computed shades instead.
     private static readonly Color s_defaultSystemAccentColorDark1 = Color.FromUInt32(0xFF005A9E);
     private static readonly Color s_defaultSystemAccentColorDark2 = Color.FromUInt32(0xFF004275);
     private static readonly Color s_defaultSystemAccentColorDark3 = Color.FromUInt32(0xFF002642);
@@ -118,22 +117,11 @@ internal sealed class SystemAccentColors : ResourceProvider
         {
             _invalidateColors = false;
 
-            var colorValues = GetFromOwner(Owner)?.GetColorValues();
+            var platformSettings = GetFromOwner(Owner);
 
-            _systemAccentColor = colorValues?.AccentColor1 ?? s_defaultSystemAccentColor;
+            _systemAccentColor = platformSettings?.GetColorValues().AccentColor1 ?? s_defaultSystemAccentColor;
 
-            if (colorValues is
-                {
-                    AccentColorDark1: { } dark1, AccentColorDark2: { } dark2, AccentColorDark3: { } dark3,
-                    AccentColorLight1: { } light1, AccentColorLight2: { } light2, AccentColorLight3: { } light3
-                })
-            {
-                // The platform reported the OS-computed shades (Windows, via UISettings);
-                // use them verbatim so the palette matches the OS exactly.
-                (_systemAccentColorDark1, _systemAccentColorDark2, _systemAccentColorDark3) = (dark1, dark2, dark3);
-                (_systemAccentColorLight1, _systemAccentColorLight2, _systemAccentColorLight3) = (light1, light2, light3);
-            }
-            else if (_systemAccentColor == s_defaultSystemAccentColor)
+            if (_systemAccentColor == s_defaultSystemAccentColor)
             {
                 // Platforms without a real accent color report the default; use WinUI's static
                 // shade values so the out-of-the-box palette matches WinUI exactly.

src/Avalonia.Themes.Fluent2/README.md

@@ -47,7 +47,6 @@ Migrating from `Avalonia.Themes.Fluent`: change the package reference and swap
 | Scroll bars | 16 px rail | **12 px rail, 2 px collapsed thumb** |
 | Window background | AltHigh | **SolidBackgroundFillColorBase** (#F3F3F3/#202020) |
 | Default accent shades | HSL-computed | **WinUI static values** (when no OS accent) |
-| OS accent shades (Windows) | HSL-computed | **read from the OS** (`UISettings` Light1–3/Dark1–3) |
 
 One deliberate deviation from WinUI (following FluentAvalonia's lead): CheckBox
 and RadioButton do **not** get WinUI's forced 120 px `MinWidth` — they size to
@@ -80,10 +79,8 @@ English-only for now.
 - No HighContrast variant yet (same as v1).
 - AnimatedIcon glyph animations are approximated with static glyphs and simple
   transitions.
-- On Windows the six accent shades (`SystemAccentColorDark1`…`Light3`) come
-  straight from the OS; on platforms that report only a base accent color
-  (macOS, Linux) the shades are HSL-computed and can deviate slightly from
-  Windows' palette algorithm.
+- OS-provided accent colors still use HSL-computed shades, which can deviate
+  slightly from Windows' palette algorithm.
 
 ## Compatibility tests
 

src/Windows/Avalonia.Win32/Win32PlatformSettings.cs

@@ -86,13 +86,7 @@ internal class Win32PlatformSettings : DefaultPlatformSettings
                     PlatformThemeVariant.Dark :
                     PlatformThemeVariant.Light,
                 ContrastPreference = ColorContrastPreference.NoPreference,
-                AccentColor1 = accent,
-                AccentColorDark1 = uiSettings.GetColorValue(UIColorType.AccentDark1).ToAvalonia(),
-                AccentColorDark2 = uiSettings.GetColorValue(UIColorType.AccentDark2).ToAvalonia(),
-                AccentColorDark3 = uiSettings.GetColorValue(UIColorType.AccentDark3).ToAvalonia(),
-                AccentColorLight1 = uiSettings.GetColorValue(UIColorType.AccentLight1).ToAvalonia(),
-                AccentColorLight2 = uiSettings.GetColorValue(UIColorType.AccentLight2).ToAvalonia(),
-                AccentColorLight3 = uiSettings.GetColorValue(UIColorType.AccentLight3).ToAvalonia()
+                AccentColor1 = accent
             };
         }
     }

tests/Avalonia.Themes.Fluent2.UnitTests/PaletteTests.cs

@@ -1,6 +1,5 @@
 using Avalonia.Controls;
 using Avalonia.Media;
-using Avalonia.Platform;
 using Avalonia.Styling;
 
 namespace Avalonia.Themes.Fluent2.UnitTests;
@@ -66,48 +65,6 @@ public class PaletteTests
         }
     }
 
-    [AvaloniaFact]
-    public void Platform_provided_accent_shades_take_precedence_over_computed_ones()
-    {
-        var originalSettings = AvaloniaLocator.Current.GetService<IPlatformSettings>();
-        Assert.NotNull(originalSettings);
-        AvaloniaLocator.CurrentMutable.Bind<IPlatformSettings>().ToConstant(new ShadeReportingPlatformSettings());
-
-        var theme = new Fluent2Theme();
-        var app = Application.Current!;
-        app.Styles.Add(theme);
-        try
-        {
-            Assert.True(app.TryGetResource("SystemAccentColor", ThemeVariant.Light, out var accent));
-            Assert.Equal(Colors.Crimson, Assert.IsType<Color>(accent));
-
-            // The OS-reported shades are used verbatim, not HSL-computed from the base color.
-            Assert.True(app.TryGetResource("SystemAccentColorDark1", ThemeVariant.Light, out var dark1));
-            Assert.Equal(Colors.DarkRed, Assert.IsType<Color>(dark1));
-            Assert.True(app.TryGetResource("SystemAccentColorLight3", ThemeVariant.Light, out var light3));
-            Assert.Equal(Colors.MistyRose, Assert.IsType<Color>(light3));
-        }
-        finally
-        {
-            app.Styles.Remove(theme);
-            AvaloniaLocator.CurrentMutable.Bind<IPlatformSettings>().ToConstant(originalSettings);
-        }
-    }
-
-    private sealed class ShadeReportingPlatformSettings : DefaultPlatformSettings
-    {
-        public override PlatformColorValues GetColorValues() => new()
-        {
-            AccentColor1 = Colors.Crimson,
-            AccentColorDark1 = Colors.DarkRed,
-            AccentColorDark2 = Colors.Maroon,
-            AccentColorDark3 = Colors.Brown,
-            AccentColorLight1 = Colors.Salmon,
-            AccentColorLight2 = Colors.LightSalmon,
-            AccentColorLight3 = Colors.MistyRose,
-        };
-    }
-
     [AvaloniaFact]
     public void Legacy_palette_colors_derive_fluent2_tokens()
     {