Exposed AccentColorInfo data from accent analyzer

Author: Avid29

components/AccentAnalyzer/src/AccentAnalyzer.Clustering.cs

@@ -147,14 +147,14 @@ private static int FindNearestClusterIndex(Vector3 point, Span<Vector3> centroid
         return nearestIndex;
     }
 
-    private static float FindColorfulness(Vector3 color)
+    internal static float FindColorfulness(Vector3 color)
     {
         var rg = color.X - color.Y;
         var yb = ((color.X + color.Y) / 2) - color.Z;
         return 0.3f * new Vector2(rg, yb).Length();
     }
 
-    private static float FindColorfulness(Vector3[] colors)
+    internal static float FindColorfulness(Vector3[] colors)
     {
         // Isolate rg and yb
         var rg = colors.Select(x => Math.Abs(x.X - x.Y));

components/AccentAnalyzer/src/AccentAnalyzer.Properties.cs

@@ -52,6 +52,11 @@ public partial class AccentAnalyzer
     public static readonly DependencyProperty ColorfulnessProperty =
         DependencyProperty.Register(nameof(Colorfulness), typeof(float), typeof(AccentAnalyzer), new PropertyMetadata(0f));
 
+    /// <summary>
+    /// An event fired when the accent properties are updated.
+    /// </summary>
+    public event EventHandler? AccentsUpdated;
+
     /// <summary>
     /// Gets the primary accent color as extracted from the <see cref="Source"/>.
     /// </summary>
@@ -125,6 +130,11 @@ public float Colorfulness
         private set => SetValue(ColorfulnessProperty, value);
     }
 
+    /// <summary>
+    /// Gets the set of <see cref="AccentColorInfo"/> extracted on last update.
+    /// </summary>
+    public IReadOnlyList<AccentColorInfo>? AccentColors { get; private set; }
+
     /// <summary>
     /// Gets a command that executes an accent update.
     /// </summary>
@@ -155,6 +165,8 @@ private void UpdateAccentProperties(Color primary, Color secondary, Color tertia
             DominantColor = dominantColor;
             BaseColor = baseColor;
             Colorfulness = colorfulness;
+
+            AccentsUpdated?.Invoke(this, EventArgs.Empty);
         });
     }
 }

components/AccentAnalyzer/src/AccentAnalyzer.cs

@@ -45,24 +45,6 @@ public void Execute(object? parameter)
         }
     }
 
-    private readonly struct AccentColorInfo
-    {
-        public AccentColorInfo(Vector3 rgb, float prominence)
-        {
-            Colorfulness = FindColorfulness(rgb);
-
-            rgb *= byte.MaxValue;
-            Color = Color.FromArgb(byte.MaxValue, (byte)rgb.X, (byte)rgb.Y, (byte)rgb.Z);
-            Prominence = prominence;
-        }
-
-        public Color Color { get; }
-
-        public float Colorfulness { get; }
-
-        public float Prominence { get; }
-    }
-
     /// <summary>
     /// Initialize an instance of the <see cref="AccentAnalyzer"/> class.
     /// </summary>
@@ -98,25 +80,33 @@ private async Task UpdateAccentAsync()
         var colorData = clusters
             .Select((color, i) => new AccentColorInfo(color, (float)sizes[i] / samples.Length));
 
+        // Update accent colors property
+        // Not a dependency property, so don't update form 
+#if !WINDOWS_UWP
+        AccentColors = [..colorData];
+#else
+        AccentColors = colorData.ToList();
+#endif
+
         // Select accent colors
         Color primary, secondary, tertiary, baseColor;
         (primary, secondary, tertiary, baseColor) = SelectAccents(colorData);
 
         // Get dominant color by prominence
-        #if NET6_0_OR_GREATER
+#if NET6_0_OR_GREATER
         var dominantColor = colorData
             .MaxBy(x => x.Prominence).Color;
-        #else
+#else
         var dominantColor = colorData
             .OrderByDescending((x) => x.Prominence)
             .First().Color;
-        #endif
+#endif
 
         // Evaluate colorfulness
         // TODO: Should this be weighted by cluster sizes?
         var overallColorfulness = FindColorfulness(clusters);
-
-        // Set the various properties from the UI thread
+        
+        // Update using the color data
         UpdateAccentProperties(primary, secondary, tertiary, baseColor, dominantColor, overallColorfulness);
     }
 
@@ -192,7 +182,7 @@ private async Task<Vector3[]> SampleSourcePixelColorsAsync(int sampleCount)
             samples[colorIndex] = new Vector3(pixelBytes[2], pixelBytes[1], pixelBytes[0]) / byte.MaxValue;
             colorIndex++;
         }
-        
+
         // If we skipped any pixels, trim the span
 #if !WINDOWS_UWP
         samples = samples[..colorIndex];

components/AccentAnalyzer/src/AccentColorInfo.cs

@@ -0,0 +1,38 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Numerics;
+using Windows.UI;
+
+namespace CommunityToolkit.WinUI.Helpers;
+
+/// <summary>
+/// A struct containing accent color info.
+/// </summary>
+public readonly struct AccentColorInfo
+{
+    internal AccentColorInfo(Vector3 rgb, float prominence)
+    {
+        Colorfulness = AccentAnalyzer.FindColorfulness(rgb);
+
+        rgb *= byte.MaxValue;
+        Color = Color.FromArgb(byte.MaxValue, (byte)rgb.X, (byte)rgb.Y, (byte)rgb.Z);
+        Prominence = prominence;
+    }
+
+    /// <summary>
+    /// Gets the <see cref="Windows.UI.Color"/> of the accent color.
+    /// </summary>
+    public Color Color { get; }
+
+    /// <summary>
+    /// Gets the colorfulness index of the accent color.
+    /// </summary>
+    public float Colorfulness { get; }
+
+    /// <summary>
+    /// Gets the prominence of the accent color in the sampled image.
+    /// </summary>
+    public float Prominence { get; }
+}