Add higher performance, mutable RGB and HSV structs

These are only for internal use with the ColorSpectrum

src/Avalonia.Controls/ColorPicker/ColorSpectrum/Hsv.cs

@@ -0,0 +1,87 @@
+// Portions of this source file are adapted from the WinUI project.
+// (https://github.com/microsoft/microsoft-ui-xaml)
+//
+// Licensed to The Avalonia Project under the MIT License.
+
+using System.Numerics;
+using Avalonia.Media;
+
+namespace Avalonia.Controls.Primitives
+{
+    /// <summary>
+    /// Contains and allows modification of Hue, Saturation and Value channel values.
+    /// </summary>
+    /// <remarks>
+    ///   The is a specialized struct optimized for permanence and memory:
+    ///   <list type="bullet">
+    ///     <item>This is not a read-only struct like <see cref="HsvColor"/> and allows editing the fields</item>
+    ///     <item>Removes the alpha component unnecessary in core calculations</item>
+    ///     <item>No channel value bounds checks or clamping is done.</item>
+    ///   </list>
+    /// </remarks>
+    internal struct Hsv
+    {
+        /// <summary>
+        /// The Hue channel value in the range from 0..359.
+        /// </summary>
+        public double H;
+
+        /// <summary>
+        /// The Saturation channel value in the range from 0..1.
+        /// </summary>
+        public double S;
+
+        /// <summary>
+        /// The Value channel value in the range from 0..1.
+        /// </summary>
+        public double V;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Hsv"/> struct.
+        /// </summary>
+        /// <param name="h">The Hue channel value in the range from 0..360.</param>
+        /// <param name="s">The Saturation channel value in the range from 0..1.</param>
+        /// <param name="v">The Value channel value in the range from 0..1.</param>
+        public Hsv(double h, double s, double v)
+        {
+            H = h;
+            S = s;
+            V = v;
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Hsv"/> struct.
+        /// </summary>
+        /// <param name="hsvColor">An existing <see cref="HsvColor"/> to convert to <see cref="Hsv"/>.</param>
+        public Hsv(HsvColor hsvColor)
+        {
+            H = hsvColor.H;
+            S = hsvColor.S;
+            V = hsvColor.V;
+        }
+
+        /// <summary>
+        /// Converts this <see cref="Hsv"/> struct into a standard <see cref="HsvColor"/>.
+        /// </summary>
+        /// <param name="alpha">The Alpha channel value in the range from 0..1.</param>
+        /// <returns>A new <see cref="HsvColor"/> representing this <see cref="Hsv"/> struct.</returns>
+        public HsvColor ToHsvColor(double alpha = 1.0)
+        {
+            // Clamping is done automatically in the constructor
+            return HsvColor.FromAhsv(alpha, H, S, V);
+        }
+
+        /// <summary>
+        /// Returns the <see cref="Rgb"/> color model equivalent of this <see cref="Hsv"/> color.
+        /// </summary>
+        /// <returns>The <see cref="Rgb"/> equivalent color.</returns>
+        public Rgb ToRgb()
+        {
+            // Instantiating a Color is unfortunately necessary to use existing conversions
+            // Clamping is done internally in the conversion method
+            Color color = HsvColor.ToRgb(H, S, V);
+
+            return new Rgb(color);
+        }
+    }
+}

src/Avalonia.Controls/ColorPicker/ColorSpectrum/Rgb.cs

@@ -0,0 +1,94 @@
+// Portions of this source file are adapted from the WinUI project.
+// (https://github.com/microsoft/microsoft-ui-xaml)
+//
+// Licensed to The Avalonia Project under the MIT License.
+
+using System;
+using Avalonia.Media;
+using Avalonia.Utilities;
+
+namespace Avalonia.Controls.Primitives
+{
+    /// <summary>
+    /// Contains and allows modification of Red, Green and Blue channel values.
+    /// </summary>
+    /// <remarks>
+    ///   The is a specialized struct optimized for permanence and memory:
+    ///   <list type="bullet">
+    ///     <item>This is not a read-only struct like <see cref="Color"/> and allows editing the fields</item>
+    ///     <item>Removes the alpha component unnecessary in core calculations</item>
+    ///     <item>Normalizes RGB channel values in the range of 0..1 to simplify calculations.</item>
+    ///     <item>No channel value bounds checks or clamping is done.</item>
+    ///   </list>
+    /// </remarks>
+    internal struct Rgb
+    {
+        /// <summary>
+        /// The Red channel value in the range from 0..1.
+        /// </summary>
+        public double R;
+
+        /// <summary>
+        /// The Green channel value in the range from 0..1.
+        /// </summary>
+        public double G;
+
+        /// <summary>
+        /// The Blue channel value in the range from 0..1.
+        /// </summary>
+        public double B;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Rgb"/> struct.
+        /// </summary>
+        /// <param name="r">The Red channel value in the range from 0..1.</param>
+        /// <param name="g">The Green channel value in the range from 0..1.</param>
+        /// <param name="b">The Blue channel value in the range from 0..1.</param>
+        public Rgb(double r, double g, double b)
+        {
+            R = r;
+            G = g;
+            B = b;
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Rgb"/> struct.
+        /// </summary>
+        /// <param name="color">An existing <see cref="Color"/> to convert to <see cref="Rgb"/>.</param>
+        public Rgb(Color color)
+        {
+            R = color.R / 255.0;
+            G = color.G / 255.0;
+            B = color.B / 255.0;
+        }
+
+        /// <summary>
+        /// Converts this <see cref="Rgb"/> struct into a standard <see cref="Color"/>.
+        /// </summary>
+        /// <param name="alpha">The Alpha channel value in the range from 0..1.</param>
+        /// <returns>A new <see cref="Color"/> representing this <see cref="Rgb"/> struct.</returns>
+        public Color ToColor(double alpha = 1.0)
+        {
+            return Color.FromArgb(
+                (byte)MathUtilities.Clamp(alpha * 255.0, 0x00, 0xFF),
+                (byte)MathUtilities.Clamp(R * 255.0, 0x00, 0xFF),
+                (byte)MathUtilities.Clamp(G * 255.0, 0x00, 0xFF),
+                (byte)MathUtilities.Clamp(B * 255.0, 0x00, 0xFF));
+        }
+
+        /// <summary>
+        /// Returns the <see cref="Hsv"/> color model equivalent of this <see cref="Rgb"/> color.
+        /// </summary>
+        /// <returns>The <see cref="Hsv"/> equivalent color.</returns>
+        public Hsv ToHsv()
+        {
+            // Instantiating an HsvColor is unfortunately necessary to use existing conversions
+            HsvColor hsvColor = HsvColor.FromRgb(
+                MathUtilities.Clamp(R, 0.0, 1.0),
+                MathUtilities.Clamp(G, 0.0, 1.0),
+                MathUtilities.Clamp(B, 0.0, 1.0));
+
+            return new Hsv(hsvColor);
+        }
+    }
+}