Update TPacked signature

Removes boxing allocation when comparing generic packed value.

src/ImageSharp/Colors/PackedPixel/IPackedPixel.cs

@@ -5,12 +5,13 @@
 
 namespace ImageSharp
 {
+    using System;
     /// <summary>
     /// An interface that represents a packed pixel type.
     /// </summary>
     /// <typeparam name="TPacked">The packed format. <example>uint, long, float.</example></typeparam>
     public interface IPackedPixel<TPacked> : IPackedVector<TPacked>, IPackedBytes
-        where TPacked : struct
+        where TPacked : struct, IEquatable<TPacked>
     {
     }
 }

src/ImageSharp/Colors/PackedPixel/IPackedVector.cs

@@ -5,6 +5,7 @@
 
 namespace ImageSharp
 {
+    using System;
     using System.Numerics;
 
     /// <summary>
@@ -13,7 +14,7 @@ namespace ImageSharp
     /// </summary>
     /// <typeparam name="TPacked">The packed format. <example>uint, long, float.</example></typeparam>
     public interface IPackedVector<TPacked> : IPackedVector
-        where TPacked : struct
+        where TPacked : struct, IEquatable<TPacked>
     {
         /// <summary>
         /// Gets or sets the packed representation of the value.

src/ImageSharp/Common/Extensions/ArrayExtensions.cs

@@ -5,6 +5,8 @@
 
 namespace ImageSharp
 {
+    using System;
+
     /// <summary>
     /// Extension methods for arrays.
     /// </summary>
@@ -21,7 +23,7 @@ public static class ArrayExtensions
         /// <returns>The <see cref="PixelAccessor{TColor,TPacked}"/></returns>
         public static PixelAccessor<TColor, TPacked> Lock<TColor, TPacked>(this TColor[] pixels, int width, int height)
             where TColor : struct, IPackedPixel<TPacked>
-            where TPacked : struct
+            where TPacked : struct, IEquatable<TPacked>
         {
             return new PixelAccessor<TColor, TPacked>(width, height, pixels);
         }

src/ImageSharp/Common/Helpers/ImageMaths.cs

@@ -166,7 +166,7 @@ public static Rectangle GetBoundingRectangle(Rectangle rectangle, Matrix3x2 matr
         /// </returns>
         public static Rectangle GetFilteredBoundingRectangle<TColor, TPacked>(ImageBase<TColor, TPacked> bitmap, float componentValue, RgbaComponent channel = RgbaComponent.B)
             where TColor : struct, IPackedPixel<TPacked>
-            where TPacked : struct
+            where TPacked : struct, IEquatable<TPacked>
         {
             const float Epsilon = .00001f;
             int width = bitmap.Width;

src/ImageSharp/Drawing/Brushes/Brushes`2.cs

@@ -3,6 +3,8 @@
 // Licensed under the Apache License, Version 2.0.
 // </copyright>
 
+using System;
+
 namespace ImageSharp.Drawing.Brushes
 {
     /// <summary>
@@ -13,7 +15,7 @@ namespace ImageSharp.Drawing.Brushes
     /// <returns>A Brush</returns>
     public class Brushes<TColor, TPacked>
         where TColor : struct, IPackedPixel<TPacked>
-        where TPacked : struct
+        where TPacked : struct, IEquatable<TPacked>
     {
         /// <summary>
         /// Percent10 Hatch Pattern

src/ImageSharp/Drawing/Brushes/IBrush.cs

@@ -5,6 +5,8 @@
 
 namespace ImageSharp.Drawing
 {
+    using System;
+
     using Processors;
 
     /// <summary>
@@ -18,7 +20,7 @@ namespace ImageSharp.Drawing
     /// </remarks>
     public interface IBrush<TColor, TPacked>
         where TColor : struct, IPackedPixel<TPacked>
-        where TPacked : struct
+        where TPacked : struct, IEquatable<TPacked>
     {
         /// <summary>
         /// Creates the applicator for this brush.

src/ImageSharp/Drawing/Brushes/ImageBrush`2.cs

@@ -17,7 +17,7 @@ namespace ImageSharp.Drawing.Brushes
     /// <typeparam name="TPacked">The packed format. <example>uint, long, float.</example></typeparam>
     public class ImageBrush<TColor, TPacked> : IBrush<TColor, TPacked>
         where TColor : struct, IPackedPixel<TPacked>
-        where TPacked : struct
+        where TPacked : struct, IEquatable<TPacked>
     {
         /// <summary>
         /// The image to paint.

src/ImageSharp/Drawing/Brushes/PatternBrush`2.cs

@@ -8,6 +8,7 @@ namespace ImageSharp.Drawing.Brushes
     using System.Numerics;
 
     using Processors;
+    using System;
 
     /// <summary>
     /// Provides an implementation of a pattern brush for painting patterns.
@@ -43,7 +44,7 @@ namespace ImageSharp.Drawing.Brushes
     /// <typeparam name="TPacked">The packed format. <example>uint, long, float.</example></typeparam>
     public class PatternBrush<TColor, TPacked> : IBrush<TColor, TPacked>
         where TColor : struct, IPackedPixel<TPacked>
-        where TPacked : struct
+        where TPacked : struct, IEquatable<TPacked>
     {
         /// <summary>
         /// The pattern.

src/ImageSharp/Drawing/Brushes/Processors/IBrushApplicator.cs

@@ -16,7 +16,7 @@ namespace ImageSharp.Drawing.Processors
     /// <seealso cref="System.IDisposable" />
     public interface IBrushApplicator<TColor, TPacked> : IDisposable // disposable will be required if/when there is an ImageBrush
         where TColor : struct, IPackedPixel<TPacked>
-        where TPacked : struct
+        where TPacked : struct, IEquatable<TPacked>
     {
         /// <summary>
         /// Gets the color for a single pixel.

src/ImageSharp/Drawing/Brushes/SolidBrush`2.cs

@@ -5,6 +5,7 @@
 
 namespace ImageSharp.Drawing.Brushes
 {
+    using System;
     using System.Numerics;
 
     using Processors;
@@ -16,7 +17,7 @@ namespace ImageSharp.Drawing.Brushes
     /// <typeparam name="TPacked">The packed format. <example>uint, long, float.</example></typeparam>
     public class SolidBrush<TColor, TPacked> : IBrush<TColor, TPacked>
         where TColor : struct, IPackedPixel<TPacked>
-        where TPacked : struct
+        where TPacked : struct, IEquatable<TPacked>
     {
         /// <summary>
         /// The color to paint.