Remove nullable disable from ColorSpace and Color

#2231

src/ImageSharp/Color/Color.cs

@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Numerics;
 using System.Runtime.CompilerServices;
@@ -20,7 +19,7 @@ namespace SixLabors.ImageSharp;
 public readonly partial struct Color : IEquatable<Color>
 {
     private readonly Rgba64 data;
-    private readonly IPixel boxedHighPrecisionPixel;
+    private readonly IPixel? boxedHighPrecisionPixel;
 
     [MethodImpl(InliningOptions.ShortMethod)]
     private Color(byte r, byte g, byte b, byte a)
@@ -317,7 +316,7 @@ public readonly partial struct Color : IEquatable<Color>
     }
 
     /// <inheritdoc />
-    public override bool Equals(object obj) => obj is Color other && this.Equals(other);
+    public override bool Equals(object? obj) => obj is Color other && this.Equals(other);
 
     /// <inheritdoc />
     [MethodImpl(InliningOptions.ShortMethod)]

src/ImageSharp/ColorSpaces/Conversion/ColorSpaceConverter.Adapt.cs

@@ -32,7 +32,8 @@ public partial class ColorSpaceConverter
             return color;
         }
 
-        return this.chromaticAdaptation.Transform(color, sourceWhitePoint, targetWhitePoint);
+        // We know that chromaticAdaption is not null because performChromaticAdaption is checked
+        return this.chromaticAdaptation!.Transform(color, sourceWhitePoint, targetWhitePoint);
     }
 
     /// <summary>
@@ -132,7 +133,8 @@ public partial class ColorSpaceConverter
         CieXyz unadapted = converterToXYZ.Convert(color);
 
         // Adaptation
-        CieXyz adapted = this.chromaticAdaptation.Transform(unadapted, color.WorkingSpace.WhitePoint, this.targetRgbWorkingSpace.WhitePoint);
+        // We know that chromaticAdaption is not null because performChromaticAdaption is checked
+        CieXyz adapted = this.chromaticAdaptation!.Transform(unadapted, color.WorkingSpace.WhitePoint, this.targetRgbWorkingSpace.WhitePoint);
 
         // Conversion back to RGB
         return this.cieXyzToLinearRgbConverter.Convert(adapted);

src/ImageSharp/ColorSpaces/Conversion/ColorSpaceConverter.CieXyz.cs

@@ -13,7 +13,7 @@ public partial class ColorSpaceConverter
 {
     private static readonly HunterLabToCieXyzConverter HunterLabToCieXyzConverter = new();
 
-    private LinearRgbToCieXyzConverter linearRgbToCieXyzConverter;
+    private LinearRgbToCieXyzConverter? linearRgbToCieXyzConverter;
 
     /// <summary>
     /// Converts a <see cref="CieLab"/> into a <see cref="CieXyz"/>.

src/ImageSharp/ColorSpaces/Conversion/ColorSpaceConverter.cs

@@ -1,7 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
+using System.Diagnostics.CodeAnalysis;
 using System.Numerics;
 
 namespace SixLabors.ImageSharp.ColorSpaces.Conversion;
@@ -19,7 +19,7 @@ public partial class ColorSpaceConverter
     private readonly CieXyz targetLabWhitePoint;
     private readonly CieXyz targetHunterLabWhitePoint;
     private readonly RgbWorkingSpace targetRgbWorkingSpace;
-    private readonly IChromaticAdaptation chromaticAdaptation;
+    private readonly IChromaticAdaptation? chromaticAdaptation;
     private readonly bool performChromaticAdaptation;
     private readonly CieXyzAndLmsConverter cieXyzAndLmsConverter;
     private readonly CieXyzToCieLabConverter cieXyzToCieLabConverter;

src/ImageSharp/ColorSpaces/Conversion/ColorSpaceConverterOptions.cs

@@ -44,7 +44,7 @@ public class ColorSpaceConverterOptions
     /// <summary>
     /// Gets or sets the chromatic adaptation method used. When <value>null</value>, no adaptation will be performed.
     /// </summary>
-    public IChromaticAdaptation ChromaticAdaptation { get; set; } = new VonKriesChromaticAdaptation();
+    public IChromaticAdaptation? ChromaticAdaptation { get; set; } = new VonKriesChromaticAdaptation();
 
     /// <summary>
     /// Gets or sets transformation matrix used in conversion to and from <see cref="Lms"/>.