Use jagged arrays

src/ImageSharp/Dithering/ErrorDiffusion/Atkinson.cs

@@ -14,11 +14,11 @@ namespace ImageSharp.Dithering
         /// <summary>
         /// The diffusion matrix
         /// </summary>
-        private static readonly byte[,] AtkinsonMatrix =
+        private static readonly byte[][] AtkinsonMatrix =
             {
-                { 0, 0, 1, 1 },
-                { 1, 1, 1, 0 },
-                { 0, 1, 0, 0 }
+               new byte[] { 0, 0, 1, 1 },
+               new byte[] { 1, 1, 1, 0 },
+               new byte[] { 0, 1, 0, 0 }
             };
 
         /// <summary>

src/ImageSharp/Dithering/ErrorDiffusion/Burks.cs

@@ -14,10 +14,10 @@ namespace ImageSharp.Dithering
         /// <summary>
         /// The diffusion matrix
         /// </summary>
-        private static readonly byte[,] BurksMatrix =
+        private static readonly byte[][] BurksMatrix =
             {
-                { 0, 0, 0, 8, 4 },
-                { 2, 4, 8, 4, 2 }
+                new byte[] { 0, 0, 0, 8, 4 },
+                new byte[] { 2, 4, 8, 4, 2 }
             };
 
         /// <summary>

src/ImageSharp/Dithering/ErrorDiffusion/ErrorDiffuser.cs

@@ -39,20 +39,20 @@ namespace ImageSharp.Dithering
         /// </summary>
         /// <param name="matrix">The dithering matrix.</param>
         /// <param name="divisor">The divisor.</param>
-        protected ErrorDiffuser(byte[,] matrix, byte divisor)
+        protected ErrorDiffuser(byte[][] matrix, byte divisor)
         {
             Guard.NotNull(matrix, nameof(matrix));
             Guard.MustBeGreaterThan(divisor, 0, nameof(divisor));
 
             this.Matrix = matrix;
-            this.matrixWidth = (byte)(matrix.GetUpperBound(1) + 1);
-            this.matrixHeight = (byte)(matrix.GetUpperBound(0) + 1);
+            this.matrixWidth = (byte)matrix[0].Length;
+            this.matrixHeight = (byte)matrix.Length;
             this.divisorVector = new Vector4(divisor);
 
             this.startingOffset = 0;
             for (int i = 0; i < this.matrixWidth; i++)
             {
-                if (matrix[0, i] != 0)
+                if (matrix[0][i] != 0)
                 {
                     this.startingOffset = (byte)(i - 1);
                     break;
@@ -61,7 +61,7 @@ namespace ImageSharp.Dithering
         }
 
         /// <inheritdoc />
-        public byte[,] Matrix { get; }
+        public byte[][] Matrix { get; }
 
         /// <inheritdoc />
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -85,13 +85,13 @@ namespace ImageSharp.Dithering
 
                     if (matrixX > 0 && matrixX < width && matrixY > 0 && matrixY < height)
                     {
-                        byte coefficient = this.Matrix[row, col];
+                        byte coefficient = this.Matrix[row][col];
                         if (coefficient == 0)
                         {
                             continue;
                         }
 
-                        Vector4 coefficientVector = new Vector4(this.Matrix[row, col]);
+                        Vector4 coefficientVector = new Vector4(this.Matrix[row][col]);
                         Vector4 offsetColor = pixels[matrixX, matrixY].ToVector4();
                         Vector4 result = ((error * coefficientVector) / this.divisorVector) + offsetColor;
                         result.W = offsetColor.W;

src/ImageSharp/Dithering/ErrorDiffusion/FloydSteinberg.cs

@@ -14,10 +14,10 @@ namespace ImageSharp.Dithering
         /// <summary>
         /// The diffusion matrix
         /// </summary>
-        private static readonly byte[,] FloydSteinbergMatrix =
+        private static readonly byte[][] FloydSteinbergMatrix =
             {
-                { 0, 0, 7 },
-                { 3, 5, 1 }
+                new byte[] { 0, 0, 7 },
+                new byte[] { 3, 5, 1 }
             };
 
         /// <summary>

src/ImageSharp/Dithering/ErrorDiffusion/IErrorDiffuser.cs

@@ -15,7 +15,7 @@ namespace ImageSharp.Dithering
         /// <summary>
         /// Gets the dithering matrix
         /// </summary>
-        byte[,] Matrix { get; }
+        byte[][] Matrix { get; }
 
         /// <summary>
         /// Transforms the image applying the dither matrix. This method alters the input pixels array

src/ImageSharp/Dithering/ErrorDiffusion/JarvisJudiceNinke.cs

@@ -14,11 +14,11 @@ namespace ImageSharp.Dithering
         /// <summary>
         /// The diffusion matrix
         /// </summary>
-        private static readonly byte[,] JarvisJudiceNinkeMatrix =
+        private static readonly byte[][] JarvisJudiceNinkeMatrix =
             {
-                { 0, 0, 0, 7, 5 },
-                { 3, 5, 7, 5, 3 },
-                { 1, 3, 5, 3, 1 }
+                new byte[] { 0, 0, 0, 7, 5 },
+                new byte[] { 3, 5, 7, 5, 3 },
+                new byte[] { 1, 3, 5, 3, 1 }
             };
 
         /// <summary>

src/ImageSharp/Dithering/ErrorDiffusion/Sierra2.cs

@@ -14,10 +14,10 @@ namespace ImageSharp.Dithering
         /// <summary>
         /// The diffusion matrix
         /// </summary>
-        private static readonly byte[,] Sierra2Matrix =
+        private static readonly byte[][] Sierra2Matrix =
             {
-               { 0, 0, 0, 4, 3 },
-               { 1, 2, 3, 2, 1 }
+               new byte[] { 0, 0, 0, 4, 3 },
+               new byte[] { 1, 2, 3, 2, 1 }
             };
 
         /// <summary>

src/ImageSharp/Dithering/ErrorDiffusion/Sierra3.cs

@@ -14,11 +14,11 @@ namespace ImageSharp.Dithering
         /// <summary>
         /// The diffusion matrix
         /// </summary>
-        private static readonly byte[,] Sierra3Matrix =
+        private static readonly byte[][] Sierra3Matrix =
             {
-               { 0, 0, 0, 5, 3 },
-               { 2, 4, 5, 4, 2 },
-               { 0, 2, 3, 2, 0 }
+               new byte[] { 0, 0, 0, 5, 3 },
+               new byte[] { 2, 4, 5, 4, 2 },
+               new byte[] { 0, 2, 3, 2, 0 }
             };
 
         /// <summary>

src/ImageSharp/Dithering/ErrorDiffusion/SierraLite.cs

@@ -14,10 +14,10 @@ namespace ImageSharp.Dithering
         /// <summary>
         /// The diffusion matrix
         /// </summary>
-        private static readonly byte[,] SierraLiteMatrix =
+        private static readonly byte[][] SierraLiteMatrix =
             {
-               { 0, 0, 2 },
-               { 1, 1, 0 }
+               new byte[] { 0, 0, 2 },
+               new byte[] { 1, 1, 0 }
             };
 
         /// <summary>

src/ImageSharp/Dithering/ErrorDiffusion/Stucki.cs

@@ -14,11 +14,11 @@ namespace ImageSharp.Dithering
         /// <summary>
         /// The diffusion matrix
         /// </summary>
-        private static readonly byte[,] StuckiMatrix =
+        private static readonly byte[][] StuckiMatrix =
             {
-               { 0, 0, 0, 8, 4 },
-               { 2, 4, 8, 4, 2 },
-               { 1, 2, 4, 2, 1 }
+               new byte[] { 0, 0, 0, 8, 4 },
+               new byte[] { 2, 4, 8, 4, 2 },
+               new byte[] { 1, 2, 4, 2, 1 }
             };
 
         /// <summary>

src/ImageSharp/Dithering/Ordered/Bayer.cs

@@ -17,23 +17,23 @@ namespace ImageSharp.Dithering.Ordered
         /// The threshold matrix.
         /// This is calculated by multiplying each value in the original matrix by 16 and subtracting 1
         /// </summary>
-        private static readonly byte[,] ThresholdMatrix =
+        private static readonly byte[][] ThresholdMatrix =
         {
-            { 15, 143, 47, 175 },
-            { 207, 79, 239, 111 },
-            { 63, 191, 31, 159 },
-            { 255, 127, 223, 95 }
+            new byte[] { 15, 143, 47, 175 },
+            new byte[] { 207, 79, 239, 111 },
+            new byte[] { 63, 191, 31, 159 },
+            new byte[] { 255, 127, 223, 95 }
         };
 
         /// <inheritdoc />
-        public byte[,] Matrix { get; } = ThresholdMatrix;
+        public byte[][] Matrix { get; } = ThresholdMatrix;
 
         /// <inheritdoc />
         public void Dither<TColor>(PixelAccessor<TColor> pixels, TColor source, TColor upper, TColor lower, byte[] bytes, int index, int x, int y, int width, int height)
             where TColor : struct, IPackedPixel, IEquatable<TColor>
         {
             source.ToXyzwBytes(bytes, 0);
-            pixels[x, y] = ThresholdMatrix[x % 3, y % 3] >= bytes[index] ? lower : upper;
+            pixels[x, y] = ThresholdMatrix[x % 3][y % 3] >= bytes[index] ? lower : upper;
         }
     }
 }

src/ImageSharp/Dithering/Ordered/IOrderedDither.cs

@@ -15,7 +15,7 @@ namespace ImageSharp.Dithering
         /// <summary>
         /// Gets the dithering matrix
         /// </summary>
-        byte[,] Matrix { get; }
+        byte[][] Matrix { get; }
 
         /// <summary>
         /// Transforms the image applying the dither matrix. This method alters the input pixels array

src/ImageSharp/Dithering/Ordered/Ordered.cs

@@ -17,23 +17,23 @@ namespace ImageSharp.Dithering.Ordered
         /// The threshold matrix.
         /// This is calculated by multiplying each value in the original matrix by 16
         /// </summary>
-        private static readonly byte[,] ThresholdMatrix =
+        private static readonly byte[][] ThresholdMatrix =
         {
-            { 0, 128, 32, 160 },
-            { 192, 64, 224, 96 },
-            { 48, 176, 16, 144 },
-            { 240, 112, 208, 80 }
+           new byte[] { 0, 128, 32, 160 },
+           new byte[] { 192, 64, 224, 96 },
+           new byte[] { 48, 176, 16, 144 },
+           new byte[] { 240, 112, 208, 80 }
         };
 
         /// <inheritdoc />
-        public byte[,] Matrix { get; } = ThresholdMatrix;
+        public byte[][] Matrix { get; } = ThresholdMatrix;
 
         /// <inheritdoc />
         public void Dither<TColor>(PixelAccessor<TColor> pixels, TColor source, TColor upper, TColor lower, byte[] bytes, int index, int x, int y, int width, int height)
             where TColor : struct, IPackedPixel, IEquatable<TColor>
         {
             source.ToXyzwBytes(bytes, 0);
-            pixels[x, y] = ThresholdMatrix[x % 3, y % 3] >= bytes[index] ? lower : upper;
+            pixels[x, y] = ThresholdMatrix[x % 3][y % 3] >= bytes[index] ? lower : upper;
         }
     }
 }