Add variable colors

.editorconfig

@@ -86,3 +86,15 @@ dotnet_diagnostic.SA1133.severity = none
 
 # IDE0001: Simplify Names
 dotnet_diagnostic.IDE0001.severity = warning
+
+# IDE0079: Remove unnecessary suppression
+dotnet_diagnostic.IDE0079.severity = none
+
+# S1244: Floating point numbers should not be tested for equality
+dotnet_diagnostic.S1244.severity = none
+
+# IDE0045: Convert to conditional expression
+dotnet_diagnostic.IDE0045.severity = none
+
+# IDE0046: Convert to conditional expression
+dotnet_diagnostic.IDE0046.severity = none

MiraAPI.Example/ExampleColors.cs

@@ -1,4 +1,6 @@
 using MiraAPI.Colors;
+using MiraAPI.Colors.ColorSpaces;
+using MiraAPI.Utilities;
 using UnityEngine;
 
 namespace MiraAPI.Example;
@@ -14,4 +16,9 @@ public static class ExampleColors
     public static CustomColor Rose { get; } = new("color.rose", new Color(0.98f, 0.26f, 0.62f));
 
     public static CustomColor Gold { get; } = new("color.gold", new Color(1.0f, 0.84f, 0.0f));
+
+    public static VariableColor Rainbow { get; } = new("color.rainbow", t => new HsbColor(MathUtilities.PingPong(t, 1f), 1f, 1f))
+    {
+        ColorBrightness = CustomColorBrightness.Lighter,
+    };
 }

MiraAPI/Colors/ColorSpaces/CmykColor.cs

@@ -0,0 +1,105 @@
+using System;
+using System.Diagnostics.CodeAnalysis;
+using MiraAPI.Utilities;
+using UnityEngine;
+
+namespace MiraAPI.Colors.ColorSpaces;
+
+/// <summary>
+/// A struct that denotes the CMYK (Cyan, Magenta, Yellow, Key) color space.
+/// </summary>
+/// <param name="c">The cyan component.</param>
+/// <param name="m">The magenta component.</param>
+/// <param name="y">The yellow component.</param>
+/// <param name="k">The key component.</param>
+/// <param name="a">The alpha component.</param>
+[Serializable]
+[SuppressMessage("StyleCop.CSharp.NamingRules", "SA1300:Element should begin with upper-case letter", Justification = "Unity parity.")]
+public record struct CmykColor(float c, float m, float y, float k, float a = 1f)
+{
+    /// <summary>
+    /// Implicitly converts a <see cref="CmykColor"/> to a Unity <see cref="Color"/>.
+    /// </summary>
+    /// <param name="c">The color being converted.</param>
+    public static implicit operator Color(CmykColor c)
+    {
+        return ToColor(c);
+    }
+
+    /// <summary>
+    /// Implicitly converts a Unity <see cref="Color"/> to a <see cref="CmykColor"/>.
+    /// </summary>
+    /// <param name="c">The color being converted.</param>
+    public static implicit operator CmykColor(Color c)
+    {
+        return FromColor(c);
+    }
+
+    /// <summary>
+    /// Converts a <see cref="CmykColor"/> to a standard Unity RGB <see cref="Color"/>.
+    /// </summary>
+    /// <param name="cmyk">The CMYK color to convert.</param>
+    /// <returns>A Unity <see cref="Color"/> representing the same visual color.</returns>
+    public static Color ToColor(CmykColor cmyk)
+    {
+        var r = (1f - cmyk.c) * (1f - cmyk.k);
+        var g = (1f - cmyk.m) * (1f - cmyk.k);
+        var b = (1f - cmyk.y) * (1f - cmyk.k);
+
+        return new Color(MathUtilities.Clamp01(r), MathUtilities.Clamp01(g), MathUtilities.Clamp01(b), cmyk.a);
+    }
+
+    /// <summary>
+    /// Converts a standard Unity RGB <see cref="Color"/> to a <see cref="CmykColor"/>.
+    /// </summary>
+    /// <param name="color">The Unity Color to convert.</param>
+    /// <returns>A <see cref="CmykColor"/> representing the same visual color.</returns>
+    public static CmykColor FromColor(Color color)
+    {
+        var r = color.r;
+        var g = color.g;
+        var b = color.b;
+
+        var k = 1f - MathF.Max(r, MathF.Max(g, b));
+
+        if (k >= 1f)
+            return new CmykColor(0f, 0f, 0f, 1f, color.a);
+
+        var invK = 1f / (1f - k);
+
+        var c = (1f - r - k) * invK;
+        var m = (1f - g - k) * invK;
+        var y = (1f - b - k) * invK;
+
+        return new CmykColor(MathUtilities.Clamp01(c), MathUtilities.Clamp01(m), MathUtilities.Clamp01(y), MathUtilities.Clamp01(k), color.a);
+    }
+
+    /// <summary>
+    /// Linearly interpolates between two <see cref="CmykColor"/> values.
+    /// </summary>
+    /// <param name="a">The starting color.</param>
+    /// <param name="b">The ending color.</param>
+    /// <param name="t">The interpolation value between the two colors, clamped to a 0 to 1 range.</param>
+    /// <returns>The interpolated <see cref="CmykColor"/>.</returns>
+    public static CmykColor Lerp(CmykColor a, CmykColor b, float t)
+    {
+        return LerpUnclamped(a, b, MathUtilities.Clamp01(t));
+    }
+
+    /// <summary>
+    /// Linearly interpolates between two <see cref="CmykColor"/> values without clamping the interpolant.
+    /// </summary>
+    /// <param name="a">The starting color.</param>
+    /// <param name="b">The ending color.</param>
+    /// <param name="t">The interpolation value between the two colors.</param>
+    /// <returns>The interpolated <see cref="CmykColor"/>.</returns>
+    public static CmykColor LerpUnclamped(CmykColor a, CmykColor b, float t)
+    {
+        return new CmykColor(
+            MathUtilities.LerpUnclamped(a.c, b.c, t),
+            MathUtilities.LerpUnclamped(a.m, b.m, t),
+            MathUtilities.LerpUnclamped(a.y, b.y, t),
+            MathUtilities.LerpUnclamped(a.k, b.k, t),
+            MathUtilities.LerpUnclamped(a.a, b.a, t));
+    }
+}

MiraAPI/Colors/ColorSpaces/HsbColor.cs

@@ -0,0 +1,136 @@
+using System;
+using System.Diagnostics.CodeAnalysis;
+using MiraAPI.Utilities;
+using UnityEngine;
+
+namespace MiraAPI.Colors.ColorSpaces;
+
+/// <summary>
+/// A struct that denotes the HSB (Hue, Saturation, Brightness) color space.
+/// </summary>
+/// <param name="h">The hue component.</param>
+/// <param name="s">The saturation component.</param>
+/// <param name="b">The brightness component.</param>
+/// <param name="a">The alpha component.</param>
+[Serializable]
+[SuppressMessage("StyleCop.CSharp.NamingRules", "SA1300:Element should begin with upper-case letter", Justification = "Unity parity.")]
+public record struct HsbColor(float h, float s, float b, float a = 1f)
+{
+    /// <summary>
+    /// Implicitly converts an <see cref="HsbColor"/> to a Unity <see cref="Color"/>.
+    /// </summary>
+    /// <param name="c">The color being converted.</param>
+    public static implicit operator Color(HsbColor c)
+    {
+        return ToColor(c);
+    }
+
+    /// <summary>
+    /// Implicitly converts a Unity <see cref="Color"/> to an <see cref="HsbColor"/>.
+    /// </summary>
+    /// <param name="c">The color being converted.</param>
+    public static implicit operator HsbColor(Color c)
+    {
+        return FromColor(c);
+    }
+
+    /// <summary>
+    /// Converts an <see cref="HsbColor"/> to a standard Unity RGB <see cref="Color"/>.
+    /// </summary>
+    /// <param name="hsb">The HSB color to convert.</param>
+    /// <returns>A Unity <see cref="Color"/> representing the same visual color.</returns>
+    public static Color ToColor(HsbColor hsb)
+    {
+        if (hsb.s <= float.Epsilon)
+            return new Color(MathUtilities.Clamp01(hsb.b), MathUtilities.Clamp01(hsb.b), MathUtilities.Clamp01(hsb.b), hsb.a);
+
+        var c = hsb.b * hsb.s;
+        var hPrime = hsb.h * 6f;
+        var x = c * (1f - MathF.Abs((hPrime % 2f) - 1f));
+        var m = hsb.b - c;
+
+        var (r, g, b) = hPrime switch
+        {
+            < 1f => (c, x, 0f),
+            < 2f => (x, c, 0f),
+            < 3f => (0f, c, x),
+            < 4f => (0f, x, c),
+            < 5f => (x, 0f, c),
+            <= 6f => (c, 0f, x),
+            _ => (0f, 0f, 0f),
+        };
+
+        return new Color(
+            MathUtilities.Clamp01(r + m),
+            MathUtilities.Clamp01(g + m),
+            MathUtilities.Clamp01(b + m),
+            hsb.a);
+    }
+
+    /// <summary>
+    /// Converts a standard Unity RGB <see cref="Color"/> to an <see cref="HsbColor"/>.
+    /// </summary>
+    /// <param name="color">The Unity Color to convert.</param>
+    /// <returns>An <see cref="HsbColor"/> representing the same visual color.</returns>
+    public static HsbColor FromColor(Color color)
+    {
+        var max = MathF.Max(color.r, MathF.Max(color.g, color.b));
+        var min = MathF.Min(color.r, MathF.Min(color.g, color.b));
+        var delta = max - min;
+
+        var h = 0f;
+
+        if (delta > 0f)
+        {
+            if (max == color.r)
+                h = (color.g - color.b) / delta % 6f;
+            else if (max == color.g)
+                h = (color.b - color.r) / delta + 2f;
+            else
+                h = (color.r - color.g) / delta + 4f;
+
+            h /= 6f;
+
+            if (h < 0f)
+                h += 1f;
+        }
+
+        var s = max == 0f ? 0f : delta / max;
+        var b = max;
+
+        return new HsbColor(h, s, b, color.a);
+    }
+
+    /// <summary>
+    /// Linearly interpolates between two <see cref="HsbColor"/> values, using the shortest path for the hue.
+    /// </summary>
+    /// <param name="a">The starting color.</param>
+    /// <param name="b">The ending color.</param>
+    /// <param name="t">The interpolation value between the two colors, clamped to a 0 to 1 range.</param>
+    /// <returns>The interpolated <see cref="HsbColor"/>.</returns>
+    public static HsbColor Lerp(HsbColor a, HsbColor b, float t)
+    {
+        return LerpUnclamped(a, b, MathUtilities.Clamp01(t));
+    }
+
+    /// <summary>
+    /// Linearly interpolates between two <see cref="HsbColor"/> values without clamping the interpolant.
+    /// </summary>
+    /// <param name="a">The starting color.</param>
+    /// <param name="b">The ending color.</param>
+    /// <param name="t">The interpolation value between the two colors.</param>
+    /// <returns>The interpolated <see cref="HsbColor"/>.</returns>
+    public static HsbColor LerpUnclamped(HsbColor a, HsbColor b, float t)
+    {
+        var hueDifference = MathUtilities.Repeat(b.h - a.h, 1f);
+
+        if (hueDifference > 0.5f)
+            hueDifference -= 1f;
+
+        return new HsbColor(
+            MathUtilities.Repeat(a.h + (hueDifference * t), 1f),
+            MathUtilities.LerpUnclamped(a.s, b.s, t),
+            MathUtilities.LerpUnclamped(a.b, b.b, t),
+            MathUtilities.LerpUnclamped(a.a, b.a, t));
+    }
+}