Rename base interface, fix Stucki filter

src/ImageSharp/Dithering/Atkinson.cs

@@ -9,7 +9,7 @@ namespace ImageSharp.Dithering
     /// Applies error diffusion based dithering using the Atkinson image dithering algorithm.
     /// <see href="http://www.efg2.com/Lab/Library/ImageProcessing/DHALF.TXT"/>
     /// </summary>
-    public class Atkinson : ErrorDiffusion
+    public sealed class Atkinson : ErrorDiffuser
     {
         /// <summary>
         /// The diffusion matrix

src/ImageSharp/Dithering/Burks.cs

@@ -9,7 +9,7 @@ namespace ImageSharp.Dithering
     /// Applies error diffusion based dithering using the Burks image dithering algorithm.
     /// <see href="http://www.efg2.com/Lab/Library/ImageProcessing/DHALF.TXT"/>
     /// </summary>
-    public class Burks : ErrorDiffusion
+    public sealed class Burks : ErrorDiffuser
     {
         /// <summary>
         /// The diffusion matrix

src/ImageSharp/Dithering/ErrorDiffusion.cs → src/ImageSharp/Dithering/ErrorDiffuser.cs

@@ -1,4 +1,4 @@
-// <copyright file="ErrorDiffusion.cs" company="James Jackson-South">
+// <copyright file="ErrorDiffuser.cs" company="James Jackson-South">
 // Copyright (c) James Jackson-South and contributors.
 // Licensed under the Apache License, Version 2.0.
 // </copyright>
@@ -12,7 +12,7 @@ namespace ImageSharp.Dithering
     /// <summary>
     /// The base class for performing effor diffusion based dithering.
     /// </summary>
-    public abstract class ErrorDiffusion : IErrorDiffusion
+    public abstract class ErrorDiffuser : IErrorDiffuser
     {
         /// <summary>
         /// The vector to perform division.
@@ -35,11 +35,11 @@ namespace ImageSharp.Dithering
         private readonly int startingOffset;
 
         /// <summary>
-        /// Initializes a new instance of the <see cref="ErrorDiffusion"/> class.
+        /// Initializes a new instance of the <see cref="ErrorDiffuser"/> class.
         /// </summary>
         /// <param name="matrix">The dithering matrix.</param>
         /// <param name="divisor">The divisor.</param>
-        protected ErrorDiffusion(byte[,] matrix, byte divisor)
+        protected ErrorDiffuser(byte[,] matrix, byte divisor)
         {
             Guard.NotNull(matrix, nameof(matrix));
             Guard.MustBeGreaterThan(divisor, 0, nameof(divisor));

src/ImageSharp/Dithering/FloydSteinberg.cs

@@ -9,7 +9,7 @@ namespace ImageSharp.Dithering
     /// Applies error diffusion based dithering using the Floyd–Steinberg image dithering algorithm.
     /// <see href="http://www.efg2.com/Lab/Library/ImageProcessing/DHALF.TXT"/>
     /// </summary>
-    public class FloydSteinberg : ErrorDiffusion
+    public sealed class FloydSteinberg : ErrorDiffuser
     {
         /// <summary>
         /// The diffusion matrix

src/ImageSharp/Dithering/IErrorDiffusion.cs → src/ImageSharp/Dithering/IErrorDiffuser.cs

@@ -1,4 +1,4 @@
-// <copyright file="IErrorDiffusion.cs" company="James Jackson-South">
+// <copyright file="IErrorDiffuser.cs" company="James Jackson-South">
 // Copyright (c) James Jackson-South and contributors.
 // Licensed under the Apache License, Version 2.0.
 // </copyright>
@@ -10,7 +10,7 @@ namespace ImageSharp.Dithering
     /// <summary>
     /// Encapsulates properties and methods required to perfom diffused error dithering on an image.
     /// </summary>
-    public interface IErrorDiffusion
+    public interface IErrorDiffuser
     {
         /// <summary>
         /// Gets the dithering matrix

src/ImageSharp/Dithering/JarvisJudiceNinke.cs

@@ -9,7 +9,7 @@ namespace ImageSharp.Dithering
     /// Applies error diffusion based dithering using the JarvisJudiceNinke image dithering algorithm.
     /// <see href="http://www.efg2.com/Lab/Library/ImageProcessing/DHALF.TXT"/>
     /// </summary>
-    public class JarvisJudiceNinke : ErrorDiffusion
+    public sealed class JarvisJudiceNinke : ErrorDiffuser
     {
         /// <summary>
         /// The diffusion matrix

src/ImageSharp/Dithering/Sierra2.cs

@@ -9,7 +9,7 @@ namespace ImageSharp.Dithering
     /// Applies error diffusion based dithering using the Sierra2 image dithering algorithm.
     /// <see href="http://www.efg2.com/Lab/Library/ImageProcessing/DHALF.TXT"/>
     /// </summary>
-    public class Sierra2 : ErrorDiffusion
+    public sealed class Sierra2 : ErrorDiffuser
     {
         /// <summary>
         /// The diffusion matrix

src/ImageSharp/Dithering/Sierra3.cs

@@ -9,7 +9,7 @@ namespace ImageSharp.Dithering
     /// Applies error diffusion based dithering using the Sierra3 image dithering algorithm.
     /// <see href="http://www.efg2.com/Lab/Library/ImageProcessing/DHALF.TXT"/>
     /// </summary>
-    public class Sierra3 : ErrorDiffusion
+    public sealed class Sierra3 : ErrorDiffuser
     {
         /// <summary>
         /// The diffusion matrix

src/ImageSharp/Dithering/SierraLite.cs

@@ -9,7 +9,7 @@ namespace ImageSharp.Dithering
     /// Applies error diffusion based dithering using the SierraLite image dithering algorithm.
     /// <see href="http://www.efg2.com/Lab/Library/ImageProcessing/DHALF.TXT"/>
     /// </summary>
-    public class SierraLite : ErrorDiffusion
+    public sealed class SierraLite : ErrorDiffuser
     {
         /// <summary>
         /// The diffusion matrix

src/ImageSharp/Dithering/Stucki.cs

@@ -9,7 +9,7 @@ namespace ImageSharp.Dithering
     /// Applies error diffusion based dithering using the Stucki image dithering algorithm.
     /// <see href="http://www.efg2.com/Lab/Library/ImageProcessing/DHALF.TXT"/>
     /// </summary>
-    public class Stucki : ErrorDiffusion
+    public sealed class Stucki : ErrorDiffuser
     {
         /// <summary>
         /// The diffusion matrix
@@ -25,7 +25,7 @@ namespace ImageSharp.Dithering
         /// Initializes a new instance of the <see cref="Stucki"/> class.
         /// </summary>
         public Stucki()
-            : base(StuckiMatrix, 4)
+            : base(StuckiMatrix, 42)
         {
         }
     }

src/ImageSharp/Quantizers/IQuantizer.cs

@@ -42,7 +42,7 @@ namespace ImageSharp.Quantizers
         /// <summary>
         /// Gets or sets the dithering algorithm to apply to the output image.
         /// </summary>
-        IErrorDiffusion DitherType { get; set; }
+        IErrorDiffuser DitherType { get; set; }
     }
 
     /// <summary>

src/ImageSharp/Quantizers/Octree/Quantizer.cs

@@ -48,7 +48,7 @@ namespace ImageSharp.Quantizers
         public bool Dither { get; set; } = true;
 
         /// <inheritdoc />
-        public IErrorDiffusion DitherType { get; set; } = new SierraLite();
+        public IErrorDiffuser DitherType { get; set; } = new SierraLite();
 
         /// <inheritdoc/>
         public virtual QuantizedImage<TColor> Quantize(ImageBase<TColor> image, int maxColors)