Address PR Feedback

Removed not needed nullability
Refactored CurveCalculator.Calculate to not need the bang operator

Author: stefannikolei

src/ImageSharp/ColorProfiles/Icc/Calculators/CurveCalculator.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+using System.Diagnostics.CodeAnalysis;
 using SixLabors.ImageSharp.ColorProfiles.Icc.Calculators;
 using SixLabors.ImageSharp.Metadata.Profiles.Icc;
 
@@ -12,6 +13,10 @@ internal partial class CurveCalculator : ISingleCalculator
     private readonly float gamma;
     private readonly CalculationType type;
 
+    [MemberNotNullWhen(true, nameof(lutCalculator))]
+    private bool IsLut => this.type == CalculationType.Lut;
+
+
     public CurveCalculator(IccCurveTagDataEntry entry, bool inverted)
     {
         if (entry.IsIdentityResponse)
@@ -36,11 +41,22 @@ public CurveCalculator(IccCurveTagDataEntry entry, bool inverted)
     }
 
     public float Calculate(float value)
-        => this.type switch
+    {
+        if (this.IsLut)
+        {
+            return this.lutCalculator.Calculate(value);
+        }
+
+        if (this.type == CalculationType.Gamma)
         {
-            CalculationType.Identity => value,
-            CalculationType.Gamma => MathF.Pow(value, this.gamma), // TODO: This could be optimized using a LUT. See SrgbCompanding
-            CalculationType.Lut => this.lutCalculator!.Calculate(value),
-            _ => throw new InvalidOperationException("Invalid calculation type"),
-        };
+            return MathF.Pow(value, this.gamma);
+        }
+
+        if (this.type == CalculationType.Identity)
+        {
+            return value;
+        }
+
+        throw new InvalidOperationException("Invalid calculation type");
+    }
 }

src/ImageSharp/ColorProfiles/Icc/Calculators/GrayTrcCalculator.cs

@@ -11,7 +11,7 @@ internal class GrayTrcCalculator : IVector4Calculator
 {
     private readonly TrcCalculator calculator;
 
-    public GrayTrcCalculator(IccTagDataEntry? grayTrc, bool toPcs)
+    public GrayTrcCalculator(IccTagDataEntry grayTrc, bool toPcs)
         => this.calculator = new TrcCalculator([grayTrc], !toPcs);
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]

src/ImageSharp/ColorProfiles/Icc/Calculators/TrcCalculator.cs

@@ -12,7 +12,7 @@ internal class TrcCalculator : IVector4Calculator
 {
     private readonly ISingleCalculator[] calculators;
 
-    public TrcCalculator(IccTagDataEntry?[] entries, bool inverted)
+    public TrcCalculator(IccTagDataEntry[] entries, bool inverted)
     {
         Guard.NotNull(entries, nameof(entries));
 

src/ImageSharp/ColorProfiles/Icc/IccConverterBase.Checks.cs

@@ -145,8 +145,8 @@ private static ConversionMethod CheckMethod2(IccProfile profile)
     private static bool HasTag(IccProfile profile, IccProfileTag tag)
         => profile.Entries.Any(t => t.TagSignature == tag);
 
-    private static IccTagDataEntry? GetTag(IccProfile profile, IccProfileTag tag)
-        => Array.Find(profile.Entries, t => t.TagSignature == tag);
+    private static IccTagDataEntry GetTag(IccProfile profile, IccProfileTag tag)
+        => Array.Find(profile.Entries, t => t.TagSignature == tag) ?? throw new InvalidOperationException();
 
     private static T? GetTag<T>(IccProfile profile, IccProfileTag tag)
         where T : IccTagDataEntry