Merge 78bcdaa4b8 into 658afb8717

src/Avalonia.Controls.ColorPicker/Avalonia.Controls.ColorPicker.csproj

@@ -23,6 +23,7 @@
 
   <ItemGroup Label="InternalsVisibleTo">
     <InternalsVisibleTo Include="Avalonia.DesignerSupport, PublicKey=$(AvaloniaPublicKey)" />
+    <InternalsVisibleTo Include="Avalonia.Controls.UnitTests, PublicKey=$(AvaloniaPublicKey)" />
   </ItemGroup>
 
 </Project>

src/Avalonia.Controls.ColorPicker/Themes/Fluent/ColorPicker.xaml

@@ -122,7 +122,7 @@
                                               AutomationProperties.Name="Third Component"
                                               Grid.Column="0"
                                               IsAlphaVisible="False"
-                                              IsPerceptive="True"
+                                              IsPerceptive="False"
                                               Orientation="Vertical"
                                               ColorModel="Hsva"
                                               ColorComponent="{Binding ThirdComponent, ElementName=ColorSpectrum}"

src/Avalonia.Controls.ColorPicker/Themes/Fluent/ColorView.xaml

@@ -366,7 +366,7 @@
                                         AutomationProperties.Name="Third Component"
                                         Grid.Column="0"
                                         IsAlphaVisible="False"
-                                        IsPerceptive="True"
+                                        IsPerceptive="False"
                                         Orientation="Vertical"
                                         ColorModel="Hsva"
                                         ColorComponent="{Binding ThirdComponent, ElementName=ColorSpectrum}"

src/Avalonia.Controls.ColorPicker/Themes/Simple/ColorPicker.xaml

@@ -123,7 +123,7 @@
                                               AutomationProperties.Name="Third Component"
                                               Grid.Column="0"
                                               IsAlphaVisible="False"
-                                              IsPerceptive="True"
+                                              IsPerceptive="False"
                                               Orientation="Vertical"
                                               ColorModel="Hsva"
                                               ColorComponent="{Binding ThirdComponent, ElementName=ColorSpectrum}"

src/Avalonia.Controls.ColorPicker/Themes/Simple/ColorView.xaml

@@ -329,7 +329,7 @@
                                         AutomationProperties.Name="Third Component"
                                         Grid.Column="0"
                                         IsAlphaVisible="False"
-                                        IsPerceptive="True"
+                                        IsPerceptive="False"
                                         Orientation="Vertical"
                                         ColorModel="Hsva"
                                         ColorComponent="{Binding ThirdComponent, ElementName=ColorSpectrum}"

tests/Avalonia.Controls.UnitTests/Avalonia.Controls.UnitTests.csproj

@@ -23,6 +23,7 @@
     <ProjectReference Include="..\..\src\Markup\Avalonia.Markup\Avalonia.Markup.csproj" />
     <ProjectReference Include="..\..\src\Avalonia.Base\Avalonia.Base.csproj" />
     <ProjectReference Include="..\..\src\Avalonia.Controls\Avalonia.Controls.csproj" />
+    <ProjectReference Include="..\..\src\Avalonia.Controls.ColorPicker\Avalonia.Controls.ColorPicker.csproj" />
     <ProjectReference Include="..\Avalonia.UnitTests\Avalonia.UnitTests.csproj" />
     <Compile Include="../Shared/ScopedSanityCheck.cs"/>
     <Service Include="{82a7f48d-3b50-4b1e-b82e-3ada8210c358}" />

tests/Avalonia.Controls.UnitTests/ColorPickerTests/ColorPickerHelpersTests.cs

@@ -0,0 +1,110 @@
+using System;
+using System.Threading.Tasks;
+using Avalonia.Collections.Pooled;
+using Avalonia.Controls.Primitives;
+using Avalonia.Layout;
+using Avalonia.Media;
+using Avalonia.UnitTests;
+using Xunit;
+
+namespace Avalonia.Controls.UnitTests.ColorPickerTests;
+
+/// <summary>
+/// Tests that <see cref="ColorPickerHelpers.CreateComponentBitmapAsync"/> produces
+/// accurate pixel output when <c>isPerceptive=false</c> — the mode the ColorSpectrum's
+/// third-component slider should use.
+///
+/// Regression tests for https://github.com/AvaloniaUI/Avalonia/issues/20925
+/// </summary>
+public class ColorPickerHelpersTests : ScopedTestBase
+{
+    /// <summary>
+    /// When sweeping Hue at a fixed desaturated selection (S=0.2, V=0.5),
+    /// every pixel's brightest channel should be bounded by V — not boosted to 255.
+    /// </summary>
+    [Fact]
+    public async Task Hue_Slider_Bitmap_Reflects_Actual_Saturation_And_Value()
+    {
+        var selection = new HsvColor(alpha: 1.0, hue: 180, saturation: 0.2, value: 0.5);
+
+        using var pixels = await GenerateSliderBitmap(ColorComponent.Component1, selection, height: 360);
+
+        // Sample mid-strip. In HSV, max RGB channel = V for any hue.
+        var (r, g, b) = ReadPixel(pixels, row: 180);
+        var maxChannel = Math.Max(r, Math.Max(g, b));
+        double expectedMax = selection.V * 255;
+
+        Assert.InRange(maxChannel, expectedMax - 10, expectedMax + 10);
+    }
+
+    /// <summary>
+    /// When sweeping Saturation, the brightest channel at full saturation is bounded
+    /// by the current Value — not forced to 255 by perceptive V=1.0 override.
+    /// </summary>
+    [Theory]
+    [InlineData(0.1)]
+    [InlineData(0.5)]
+    [InlineData(0.9)]
+    public async Task Saturation_Slider_Bitmap_Respects_Current_Value(double currentValue)
+    {
+        var selection = new HsvColor(alpha: 1.0, hue: 200, saturation: 0.8, value: currentValue);
+
+        using var pixels = await GenerateSliderBitmap(ColorComponent.Component2, selection);
+
+        // Row 0 = highest saturation (bitmap sweeps high→low top-to-bottom).
+        var (r, g, b) = ReadPixel(pixels, row: 0);
+        var maxChannel = Math.Max(r, Math.Max(g, b));
+        double expectedMax = currentValue * 255;
+
+        Assert.InRange(maxChannel, expectedMax - 20, expectedMax + 20);
+    }
+
+    /// <summary>
+    /// When sweeping Value at low Saturation (S=0.1), the top pixel should be
+    /// near-grey (low chroma) — not vivid from a perceptive S=1.0 override.
+    /// </summary>
+    [Fact]
+    public async Task Value_Slider_Bitmap_Respects_Current_Saturation()
+    {
+        var selection = new HsvColor(alpha: 1.0, hue: 30, saturation: 0.1, value: 0.8);
+
+        using var pixels = await GenerateSliderBitmap(ColorComponent.Component3, selection);
+
+        // Row 0 = highest Value. In HSV, chroma = V * S * 255 ≤ S * 255.
+        var (r, g, b) = ReadPixel(pixels, row: 0);
+        int chroma = Math.Max(r, Math.Max(g, b)) - Math.Min(r, Math.Min(g, b));
+
+        // At S=0.1 the max possible chroma is 25.5 — near-grey for any V.
+        // With perceptive S=1.0 override, chroma would be ~252.
+        Assert.InRange(chroma, 0, selection.S * 255 + 10);
+    }
+
+    private static async Task<PooledList<byte>> GenerateSliderBitmap(
+        ColorComponent component,
+        HsvColor baseColor,
+        int height = 100)
+    {
+        const int width = 1;
+        var buffer = new PooledList<byte>(width * height * 4, ClearMode.Never, sizeToCapacity: true);
+
+        await ColorPickerHelpers.CreateComponentBitmapAsync(
+            buffer, width, height,
+            Orientation.Vertical,
+            ColorModel.Hsva,
+            component,
+            baseColor,
+            isAlphaVisible: false,
+            isPerceptive: false);
+
+        return buffer;
+    }
+
+    /// <summary>
+    /// Reads a pixel from a 1-pixel-wide vertical BGRA bitmap at the given row.
+    /// </summary>
+    private static (byte R, byte G, byte B) ReadPixel(PooledList<byte> bgraData, int row)
+    {
+        int offset = row * 4;
+        return (R: bgraData[offset + 2], G: bgraData[offset + 1], B: bgraData[offset]);
+    }
+}