Update IColorConversion to support readonly structs

src/ImageSharp/ColorSpaces/Conversion/IChromaticAdaptation.cs

@@ -1,8 +1,6 @@
 // Copyright (c) Six Labors and contributors.
 // Licensed under the Apache License, Version 2.0.
 
-using SixLabors.ImageSharp.ColorSpaces;
-
 namespace SixLabors.ImageSharp.ColorSpaces.Conversion
 {
     /// <summary>
@@ -20,6 +18,6 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         /// <param name="sourceWhitePoint">The source white point.</param>
         /// <param name="targetWhitePoint">The target white point.</param>
         /// <returns>The <see cref="CieXyz"/></returns>
-        CieXyz Transform(CieXyz sourceColor, CieXyz sourceWhitePoint, CieXyz targetWhitePoint);
+        CieXyz Transform(in CieXyz sourceColor, in CieXyz sourceWhitePoint, in CieXyz targetWhitePoint);
     }
 }

src/ImageSharp/ColorSpaces/Conversion/IColorConversion.cs

@@ -8,13 +8,15 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
     /// </summary>
     /// <typeparam name="T">The input color type.</typeparam>
     /// <typeparam name="TResult">The result color type.</typeparam>
-    internal interface IColorConversion<in T, out TResult>
+    internal interface IColorConversion<T, TResult>
+        where T : struct
+        where TResult : struct
     {
         /// <summary>
         /// Performs the conversion from the input to an instance of the output type.
         /// </summary>
         /// <param name="input">The input color instance.</param>
         /// <returns>The converted result</returns>
-        TResult Convert(T input);
+        TResult Convert(in T input);
     }
 }

src/ImageSharp/ColorSpaces/Conversion/Implementation/CieLab/CieLabToCieXyzConverter.cs

@@ -13,7 +13,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.CieLabColor
     {
         /// <inheritdoc/>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public CieXyz Convert(CieLab input)
+        public CieXyz Convert(in CieLab input)
         {
             // Conversion algorithm described here: http://www.brucelindbloom.com/index.html?Eqn_Lab_to_XYZ.html
             float l = input.L, a = input.A, b = input.B;

src/ImageSharp/ColorSpaces/Conversion/Implementation/CieLab/CieXyzToCieLabConverter.cs

@@ -33,15 +33,11 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.CieLabColor
         /// <summary>
         /// Gets the target reference whitepoint. When not set, <see cref="CieLab.DefaultWhitePoint"/> is used.
         /// </summary>
-        public CieXyz LabWhitePoint
-        {
-            [MethodImpl(MethodImplOptions.AggressiveInlining)]
-            get;
-        }
+        public CieXyz LabWhitePoint { get; }
 
         /// <inheritdoc />
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public CieLab Convert(CieXyz input)
+        public CieLab Convert(in CieXyz input)
         {
             // Conversion algorithm described here: http://www.brucelindbloom.com/index.html?Eqn_XYZ_to_Lab.html
             float wx = this.LabWhitePoint.X, wy = this.LabWhitePoint.Y, wz = this.LabWhitePoint.Z;

src/ImageSharp/ColorSpaces/Conversion/Implementation/CieLch/CIeLchToCieLabConverter.cs

@@ -13,7 +13,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.CieLchColor
     {
         /// <inheritdoc/>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public CieLab Convert(CieLch input)
+        public CieLab Convert(in CieLch input)
         {
             // Conversion algorithm described here:
             // https://en.wikipedia.org/wiki/Lab_color_space#Cylindrical_representation:_CIELCh_or_CIEHLC

src/ImageSharp/ColorSpaces/Conversion/Implementation/CieLch/CieLabToCieLchConverter.cs

@@ -13,7 +13,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.CieLchColor
     {
         /// <inheritdoc/>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public CieLch Convert(CieLab input)
+        public CieLch Convert(in CieLab input)
         {
             // Conversion algorithm described here:
             // https://en.wikipedia.org/wiki/Lab_color_space#Cylindrical_representation:_CIELCh_or_CIEHLC

src/ImageSharp/ColorSpaces/Conversion/Implementation/CieLchuv/CieLchuvToCieLuvConverter.cs

@@ -13,7 +13,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.CieLchuvCol
     {
         /// <inheritdoc/>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public CieLuv Convert(CieLchuv input)
+        public CieLuv Convert(in CieLchuv input)
         {
             // Conversion algorithm described here:
             // https://en.wikipedia.org/wiki/CIELUV#Cylindrical_representation_.28CIELCH.29

src/ImageSharp/ColorSpaces/Conversion/Implementation/CieLchuv/CieLuvToCieLchuvConverter.cs

@@ -13,7 +13,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.CieLchuvCol
     {
         /// <inheritdoc/>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public CieLchuv Convert(CieLuv input)
+        public CieLchuv Convert(in CieLuv input)
         {
             // Conversion algorithm described here:
             // https://en.wikipedia.org/wiki/CIELUV#Cylindrical_representation_.28CIELCH.29

src/ImageSharp/ColorSpaces/Conversion/Implementation/CieLuv/CieLuvToCieXyzConverter.cs

@@ -13,7 +13,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.CieLuvColor
     {
         /// <inheritdoc/>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public CieXyz Convert(CieLuv input)
+        public CieXyz Convert(in CieLuv input)
         {
             // Conversion algorithm described here: http://www.brucelindbloom.com/index.html?Eqn_Luv_to_XYZ.html
             float l = input.L, u = input.U, v = input.V;
@@ -57,7 +57,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.CieLuvColor
         /// <param name="input">The whitepoint</param>
         /// <returns>The <see cref="float"/></returns>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        private static float ComputeU0(CieXyz input)
+        private static float ComputeU0(in CieXyz input)
         {
             return (4 * input.X) / (input.X + (15 * input.Y) + (3 * input.Z));
         }
@@ -68,7 +68,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.CieLuvColor
         /// <param name="input">The whitepoint</param>
         /// <returns>The <see cref="float"/></returns>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        private static float ComputeV0(CieXyz input)
+        private static float ComputeV0(in CieXyz input)
         {
             return (9 * input.Y) / (input.X + (15 * input.Y) + (3 * input.Z));
         }

src/ImageSharp/ColorSpaces/Conversion/Implementation/CieLuv/CieXyzToCieLuvConverter.cs

@@ -34,15 +34,11 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.CieLuvColor
         /// <summary>
         /// Gets the target reference whitepoint. When not set, <see cref="CieLuv.DefaultWhitePoint"/> is used.
         /// </summary>
-        public CieXyz LuvWhitePoint
-        {
-            [MethodImpl(MethodImplOptions.AggressiveInlining)]
-            get;
-        }
+        public CieXyz LuvWhitePoint { get; }
 
         /// <inheritdoc />
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public CieLuv Convert(CieXyz input)
+        public CieLuv Convert(in CieXyz input)
         {
             // Conversion algorithm described here: http://www.brucelindbloom.com/index.html?Eqn_XYZ_to_Luv.html
             float yr = input.Y / this.LuvWhitePoint.Y;
@@ -80,7 +76,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.CieLuvColor
         /// <param name="input">The whitepoint</param>
         /// <returns>The <see cref="float"/></returns>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        private static float ComputeUp(CieXyz input)
+        private static float ComputeUp(in CieXyz input)
         {
             return (4 * input.X) / (input.X + (15 * input.Y) + (3 * input.Z));
         }
@@ -90,7 +86,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.CieLuvColor
         /// </summary>
         /// <param name="input">The whitepoint</param>
         /// <returns>The <see cref="float"/></returns>
-        private static float ComputeVp(CieXyz input)
+        private static float ComputeVp(in CieXyz input)
         {
             return (9 * input.Y) / (input.X + (15 * input.Y) + (3 * input.Z));
         }

src/ImageSharp/ColorSpaces/Conversion/Implementation/CieXyy/CieXyzAndCieXyyConverter.cs

@@ -14,7 +14,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.CieXyyColor
     {
         /// <inheritdoc/>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public CieXyy Convert(CieXyz input)
+        public CieXyy Convert(in CieXyz input)
         {
             float x = input.X / (input.X + input.Y + input.Z);
             float y = input.Y / (input.X + input.Y + input.Z);
@@ -29,7 +29,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.CieXyyColor
 
         /// <inheritdoc/>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public CieXyz Convert(CieXyy input)
+        public CieXyz Convert(in CieXyy input)
         {
             if (MathF.Abs(input.Y) < Constants.Epsilon)
             {

src/ImageSharp/ColorSpaces/Conversion/Implementation/Cmyk/CmykAndRgbConverter.cs

@@ -13,7 +13,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.CmykColorSa
     {
         /// <inheritdoc/>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public Rgb Convert(Cmyk input)
+        public Rgb Convert(in Cmyk input)
         {
             float r = (1F - input.C) * (1F - input.K);
             float g = (1F - input.M) * (1F - input.K);
@@ -24,7 +24,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.CmykColorSa
 
         /// <inheritdoc/>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public Cmyk Convert(Rgb input)
+        public Cmyk Convert(in Rgb input)
         {
             // To CMYK
             float c = 1F - input.R;

src/ImageSharp/ColorSpaces/Conversion/Implementation/Hsl/HslAndRgbConverter.cs

@@ -14,7 +14,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.HslColorSap
     {
         /// <inheritdoc/>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public Rgb Convert(Hsl input)
+        public Rgb Convert(in Hsl input)
         {
             float rangedH = input.H / 360F;
             float r = 0;
@@ -45,7 +45,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.HslColorSap
 
         /// <inheritdoc/>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public Hsl Convert(Rgb input)
+        public Hsl Convert(in Rgb input)
         {
             float r = input.R;
             float g = input.G;

src/ImageSharp/ColorSpaces/Conversion/Implementation/Hsv/HsvAndRgbConverter.cs

@@ -14,7 +14,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.HsvColorSap
     {
         /// <inheritdoc/>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public Rgb Convert(Hsv input)
+        public Rgb Convert(in Hsv input)
         {
             float s = input.S;
             float v = input.V;
@@ -77,7 +77,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.HsvColorSap
 
         /// <inheritdoc/>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public Hsv Convert(Rgb input)
+        public Hsv Convert(in Rgb input)
         {
             float r = input.R;
             float g = input.G;

src/ImageSharp/ColorSpaces/Conversion/Implementation/HunterLab/CieXyzToHunterLabConverter.cs

@@ -37,7 +37,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.HunterLabCo
 
         /// <inheritdoc/>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public HunterLab Convert(CieXyz input)
+        public HunterLab Convert(in CieXyz input)
         {
             // Conversion algorithm described here: http://en.wikipedia.org/wiki/Lab_color_space#Hunter_Lab
             float x = input.X, y = input.Y, z = input.Z;

src/ImageSharp/ColorSpaces/Conversion/Implementation/HunterLab/HunterLabToCieXyzConverter.cs

@@ -13,7 +13,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.HunterLabCo
     {
         /// <inheritdoc/>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public CieXyz Convert(HunterLab input)
+        public CieXyz Convert(in HunterLab input)
         {
             // Conversion algorithm described here: http://en.wikipedia.org/wiki/Lab_color_space#Hunter_Lab
             float l = input.L, a = input.A, b = input.B;

src/ImageSharp/ColorSpaces/Conversion/Implementation/Lms/CieXyzAndLmsConverter.cs

@@ -60,7 +60,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.LmsColorSap
 
         /// <inheritdoc/>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public Lms Convert(CieXyz input)
+        public Lms Convert(in CieXyz input)
         {
             Vector3 vector = Vector3.Transform(input.Vector, this.transformationMatrix);
             return new Lms(vector);
@@ -68,7 +68,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.LmsColorSap
 
         /// <inheritdoc/>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public CieXyz Convert(Lms input)
+        public CieXyz Convert(in Lms input)
         {
             Vector3 vector = Vector3.Transform(input.Vector, this.inverseTransformationMatrix);
             return new CieXyz(vector);

src/ImageSharp/ColorSpaces/Conversion/Implementation/Rgb/CieXyzToLinearRgbConverter.cs

@@ -36,7 +36,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.RgbColorSap
         public IRgbWorkingSpace TargetWorkingSpace { get; }
 
         /// <inheritdoc/>
-        public LinearRgb Convert(CieXyz input)
+        public LinearRgb Convert(in CieXyz input)
         {
             Matrix4x4.Invert(this.conversionMatrix, out Matrix4x4 inverted);
             Vector3 vector = Vector3.Transform(input.Vector, inverted);

src/ImageSharp/ColorSpaces/Conversion/Implementation/Rgb/LinearRgbToCieXyzConverter.cs

@@ -36,7 +36,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.RgbColorSap
         public IRgbWorkingSpace SourceWorkingSpace { get; }
 
         /// <inheritdoc/>
-        public CieXyz Convert(LinearRgb input)
+        public CieXyz Convert(in LinearRgb input)
         {
             DebugGuard.IsTrue(input.WorkingSpace.Equals(this.SourceWorkingSpace), nameof(input.WorkingSpace), "Input and source working spaces must be equal.");
 

src/ImageSharp/ColorSpaces/Conversion/Implementation/Rgb/LinearRgbToRgbConverter.cs

@@ -11,7 +11,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.RgbColorSap
     internal class LinearRgbToRgbConverter : IColorConversion<LinearRgb, Rgb>
     {
         /// <inheritdoc/>
-        public Rgb Convert(LinearRgb input)
+        public Rgb Convert(in LinearRgb input)
         {
             Vector3 vector = input.Vector;
             vector.X = input.WorkingSpace.Companding.Compress(vector.X);

src/ImageSharp/ColorSpaces/Conversion/Implementation/Rgb/RgbToLinearRgbConverter.cs

@@ -11,7 +11,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.RgbColorSap
     internal class RgbToLinearRgbConverter : IColorConversion<Rgb, LinearRgb>
     {
         /// <inheritdoc/>
-        public LinearRgb Convert(Rgb input)
+        public LinearRgb Convert(in Rgb input)
         {
             Vector3 vector = input.Vector;
             vector.X = input.WorkingSpace.Companding.Expand(vector.X);

src/ImageSharp/ColorSpaces/Conversion/Implementation/YCbCr/YCbCrAndRgbConverter.cs

@@ -17,7 +17,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.YCbCrColorS
 
         /// <inheritdoc/>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public Rgb Convert(YCbCr input)
+        public Rgb Convert(in YCbCr input)
         {
             float y = input.Y;
             float cb = input.Cb - 128F;
@@ -32,7 +32,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.YCbCrColorS
 
         /// <inheritdoc/>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public YCbCr Convert(Rgb input)
+        public YCbCr Convert(in Rgb input)
         {
             Vector3 rgb = input.Vector * MaxBytes;
             float r = rgb.X;

src/ImageSharp/ColorSpaces/Conversion/VonKriesChromaticAdaptation.cs

@@ -47,7 +47,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         }
 
         /// <inheritdoc/>
-        public CieXyz Transform(CieXyz sourceColor, CieXyz sourceWhitePoint, CieXyz targetWhitePoint)
+        public CieXyz Transform(in CieXyz sourceColor, in CieXyz sourceWhitePoint, in CieXyz targetWhitePoint)
         {
             if (sourceWhitePoint.Equals(targetWhitePoint))
             {