Introduce representation-agnostic Color type

ImageSharp.sln.DotSettings

@@ -388,5 +388,6 @@
 	<s:Boolean x:Key="/Default/Environment/SettingsMigration/IsMigratorApplied/=JetBrains_002EReSharper_002EPsi_002ECSharp_002ECodeStyle_002ESettingsUpgrade_002ECSharpPlaceAttributeOnSameLineMigration/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/Environment/SettingsMigration/IsMigratorApplied/=JetBrains_002EReSharper_002EPsi_002ECSharp_002ECodeStyle_002ESettingsUpgrade_002EMigrateBlankLinesAroundFieldToBlankLinesAroundProperty/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/Environment/SettingsMigration/IsMigratorApplied/=JetBrains_002EReSharper_002EPsi_002ECSharp_002ECodeStyle_002ESettingsUpgrade_002EMigrateThisQualifierSettings/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/UserDictionary/Words/=Bgra/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Quantizer/@EntryIndexedValue">True</s:Boolean>
 </wpf:ResourceDictionary>

src/ImageSharp/Advanced/AotCompilerTools.cs

@@ -104,7 +104,7 @@ private static void AotCompileOctreeQuantizer<TPixel>()
         private static void AotCompileWuQuantizer<TPixel>()
             where TPixel : struct, IPixel<TPixel>
         {
-            var test = new WuFrameQuantizer<TPixel>(new WuQuantizer(false));
+            var test = new WuFrameQuantizer<TPixel>(Configuration.Default.MemoryAllocator, new WuQuantizer(false));
             test.QuantizeFrame(new ImageFrame<TPixel>(Configuration.Default, 1, 1));
             test.AotGetPalette();
         }

src/ImageSharp/Color/Color.Conversions.cs

@@ -0,0 +1,83 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+using System.Numerics;
+using System.Runtime.CompilerServices;
+
+using SixLabors.ImageSharp.PixelFormats;
+
+namespace SixLabors.ImageSharp
+{
+    /// <content>
+    /// Contains constructors and implicit conversion methods.
+    /// </content>
+    public readonly partial struct Color
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Color"/> struct.
+        /// </summary>
+        /// <param name="pixel">The <see cref="Rgba64"/> containing the color information.</param>
+        [MethodImpl(InliningOptions.ShortMethod)]
+        public Color(Rgba64 pixel) => this.data = pixel;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Color"/> struct.
+        /// </summary>
+        /// <param name="pixel">The <see cref="Rgba32"/> containing the color information.</param>
+        [MethodImpl(InliningOptions.ShortMethod)]
+        public Color(Rgba32 pixel) => this.data = new Rgba64(pixel);
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Color"/> struct.
+        /// </summary>
+        /// <param name="pixel">The <see cref="Argb32"/> containing the color information.</param>
+        [MethodImpl(InliningOptions.ShortMethod)]
+        public Color(Argb32 pixel) => this.data = new Rgba64(pixel);
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Color"/> struct.
+        /// </summary>
+        /// <param name="pixel">The <see cref="Bgra32"/> containing the color information.</param>
+        [MethodImpl(InliningOptions.ShortMethod)]
+        public Color(Bgra32 pixel) => this.data = new Rgba64(pixel);
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Color"/> struct.
+        /// </summary>
+        /// <param name="pixel">The <see cref="Rgb24"/> containing the color information.</param>
+        [MethodImpl(InliningOptions.ShortMethod)]
+        public Color(Rgb24 pixel) => this.data = new Rgba64(pixel);
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Color"/> struct.
+        /// </summary>
+        /// <param name="pixel">The <see cref="Bgr24"/> containing the color information.</param>
+        [MethodImpl(InliningOptions.ShortMethod)]
+        public Color(Bgr24 pixel) => this.data = new Rgba64(pixel);
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Color"/> struct.
+        /// </summary>
+        /// <param name="vector">The <see cref="Vector4"/> containing the color information.</param>
+        [MethodImpl(InliningOptions.ShortMethod)]
+        public Color(Vector4 vector) => this.data = new Rgba64(vector);
+
+        [MethodImpl(InliningOptions.ShortMethod)]
+        internal Rgba64 ToRgba64() => this.data;
+
+        [MethodImpl(InliningOptions.ShortMethod)]
+        internal Rgba32 ToRgba32() => this.data.ToRgba32();
+
+        [MethodImpl(InliningOptions.ShortMethod)]
+        internal Bgra32 ToBgra32() => this.data.ToBgra32();
+
+        [MethodImpl(InliningOptions.ShortMethod)]
+        internal Argb32 ToArgb32() => this.data.ToArgb32();
+
+        [MethodImpl(InliningOptions.ShortMethod)]
+        internal Rgb24 ToRgb24() => this.data.ToRgb24();
+
+        [MethodImpl(InliningOptions.ShortMethod)]
+        internal Bgr24 ToBgr24() => this.data.ToBgr24();
+    }
+}