Add convolution filters

Former-commit-id: c0578b87f4443ee3508e743b2ff56ce190bc9dbc
Former-commit-id: fd223f0a81941eafdd858f5da687079bf7cf0116
Former-commit-id: 1627f2d73ebb9b1067473fa82e2edd566299a0a4

src/ImageProcessor/Filters/Convolution/Convolution2DFilter.cs

@@ -0,0 +1,97 @@
+// <copyright file="Convolution2DFilter.cs" company="James South">
+// Copyright (c) James South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+
+namespace ImageProcessor.Filters
+{
+    using System;
+    using System.Threading.Tasks;
+
+    /// <summary>
+    /// Defines a filter that uses a matrix to perform convolution across two dimensions against an image.
+    /// </summary>
+    public abstract class Convolution2DFilter : ParallelImageProcessor
+    {
+        /// <summary>
+        /// Gets the horizontal gradient operator.
+        /// </summary>
+        public abstract float[,] KernelX { get; }
+
+        /// <summary>
+        /// Gets the vertical gradient operator.
+        /// </summary>
+        public abstract float[,] KernelY { get; }
+
+        /// <inheritdoc/>
+        protected override void Apply(ImageBase target, ImageBase source, Rectangle targetRectangle, Rectangle sourceRectangle, int startY, int endY)
+        {
+            float[,] kernelX = this.KernelX;
+            float[,] kernelY = this.KernelY;
+            int kernelLength = kernelX.GetLength(0);
+            int radius = kernelLength >> 1;
+
+            int sourceY = sourceRectangle.Y;
+            int sourceBottom = sourceRectangle.Bottom;
+            int startX = sourceRectangle.X;
+            int endX = sourceRectangle.Right;
+            int maxY = sourceBottom - 1;
+            int maxX = endX - 1;
+
+            Parallel.For(
+                startY,
+                endY,
+                y =>
+                {
+                    if (y >= sourceY && y < sourceBottom)
+                    {
+                        for (int x = startX; x < endX; x++)
+                        {
+                            float rX = 0;
+                            float gX = 0;
+                            float bX = 0;
+                            float rY = 0;
+                            float gY = 0;
+                            float bY = 0;
+
+                            // Apply each matrix multiplier to the color components for each pixel.
+                            for (int fy = 0; fy < kernelLength; fy++)
+                            {
+                                int fyr = fy - radius;
+                                int offsetY = y + fyr;
+
+                                offsetY = offsetY.Clamp(0, maxY);
+
+                                for (int fx = 0; fx < kernelLength; fx++)
+                                {
+                                    int fxr = fx - radius;
+                                    int offsetX = x + fxr;
+
+                                    offsetX = offsetX.Clamp(0, maxX);
+
+                                    Color currentColor = source[offsetX, offsetY];
+                                    float r = currentColor.R;
+                                    float g = currentColor.G;
+                                    float b = currentColor.B;
+
+                                    rX += kernelX[fy, fx] * r;
+                                    gX += kernelX[fy, fx] * g;
+                                    bX += kernelX[fy, fx] * b;
+
+                                    rY += kernelY[fy, fx] * r;
+                                    gY += kernelY[fy, fx] * g;
+                                    bY += kernelY[fy, fx] * b;
+                                }
+                            }
+
+                            float red = (float)Math.Sqrt((rX * rX) + (rY * rY));
+                            float green = (float)Math.Sqrt((gX * gX) + (gY * gY));
+                            float blue = (float)Math.Sqrt((bX * bX) + (bY * bY));
+
+                            target[x, y] = new Color(red, green, blue);
+                        }
+                    }
+                });
+        }
+    }
+}

src/ImageProcessor/Filters/Convolution/ConvolutionFilter.cs

@@ -0,0 +1,83 @@
+// <copyright file="ConvolutionFilter.cs" company="James South">
+// Copyright (c) James South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+
+namespace ImageProcessor.Filters
+{
+    using System.Threading.Tasks;
+
+    /// <summary>
+    /// Defines a filter that uses a matrix to perform convolution across a single dimension against an image.
+    /// </summary>
+    public abstract class ConvolutionFilter : ParallelImageProcessor
+    {
+        /// <summary>
+        /// Gets the horizontal gradient operator.
+        /// </summary>
+        public abstract float[,] KernelX { get; }
+
+        /// <inheritdoc/>
+        protected override void Apply(ImageBase target, ImageBase source, Rectangle targetRectangle, Rectangle sourceRectangle, int startY, int endY)
+        {
+            float[,] kernelX = this.KernelX;
+            int kernelLength = kernelX.GetLength(0);
+            int radius = kernelLength >> 1;
+
+            int sourceY = sourceRectangle.Y;
+            int sourceBottom = sourceRectangle.Bottom;
+            int startX = sourceRectangle.X;
+            int endX = sourceRectangle.Right;
+            int maxY = sourceBottom - 1;
+            int maxX = endX - 1;
+
+            Parallel.For(
+                startY,
+                endY,
+                y =>
+                {
+                    if (y >= sourceY && y < sourceBottom)
+                    {
+                        for (int x = startX; x < endX; x++)
+                        {
+                            float rX = 0;
+                            float gX = 0;
+                            float bX = 0;
+
+                            // Apply each matrix multiplier to the color components for each pixel.
+                            for (int fy = 0; fy < kernelLength; fy++)
+                            {
+                                int fyr = fy - radius;
+                                int offsetY = y + fyr;
+
+                                offsetY = offsetY.Clamp(0, maxY);
+
+                                for (int fx = 0; fx < kernelLength; fx++)
+                                {
+                                    int fxr = fx - radius;
+                                    int offsetX = x + fxr;
+
+                                    offsetX = offsetX.Clamp(0, maxX);
+
+                                    Color currentColor = source[offsetX, offsetY];
+                                    float r = currentColor.R;
+                                    float g = currentColor.G;
+                                    float b = currentColor.B;
+
+                                    rX += kernelX[fy, fx] * r;
+                                    gX += kernelX[fy, fx] * g;
+                                    bX += kernelX[fy, fx] * b;
+                                }
+                            }
+
+                            float red = rX;
+                            float green = gX;
+                            float blue = bX;
+
+                            target[x, y] = new Color(red, green, blue);
+                        }
+                    }
+                });
+        }
+    }
+}

src/ImageProcessor/Filters/Convolution/Kayyali.cs

@@ -0,0 +1,34 @@
+// <copyright file="Kayyali.cs" company="James South">
+// Copyright (c) James South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+
+namespace ImageProcessor.Filters
+{
+    /// <summary>
+    /// The Kayyali operator filter.
+    /// <see href="http://edgedetection.webs.com/"/>
+    /// </summary>
+    public class Kayyali : Convolution2DFilter
+    {
+        /// <summary>
+        /// Gets the horizontal gradient operator.
+        /// </summary>
+        public override float[,] KernelX => new float[,]
+        {
+            { 6, 0, -6 },
+            { 0, 0, 0 },
+            { -6, 0, 6 }
+        };
+
+        /// <summary>
+        /// Gets the vertical gradient operator.
+        /// </summary>
+        public override float[,] KernelY => new float[,]
+        {
+            { -6, 0, 6 },
+            { 0, 0, 0 },
+            { 6, 0, -6 }
+        };
+    }
+}

src/ImageProcessor/Filters/Convolution/Kirsch.cs

@@ -0,0 +1,34 @@
+// <copyright file="Kirsch.cs" company="James South">
+// Copyright (c) James South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+
+namespace ImageProcessor.Filters
+{
+    /// <summary>
+    /// The Kirsch operator filter.
+    /// <see href="http://en.wikipedia.org/wiki/Kirsch_operator"/>
+    /// </summary>
+    public class Kirsch : Convolution2DFilter
+    {
+        /// <summary>
+        /// Gets the horizontal gradient operator.
+        /// </summary>
+        public override float[,] KernelX => new float[,]
+        {
+            { 5, 5, 5 },
+            { -3, 0, -3 },
+            { -3, -3, -3 }
+        };
+
+        /// <summary>
+        /// Gets the vertical gradient operator.
+        /// </summary>
+        public override float[,] KernelY => new float[,]
+        {
+            { 5, -3, -3 },
+            { 5,  0, -3 },
+            { 5, -3, -3 }
+        };
+    }
+}

src/ImageProcessor/Filters/Convolution/Laplacian3X3.cs

@@ -0,0 +1,24 @@
+// <copyright file="Laplacian3X3.cs" company="James South">
+// Copyright (c) James South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+
+namespace ImageProcessor.Filters
+{
+    /// <summary>
+    /// The Laplacian 3 x 3 operator filter.
+    /// <see href="http://en.wikipedia.org/wiki/Discrete_Laplace_operator"/>
+    /// </summary>
+    public class Laplacian3X3 : ConvolutionFilter
+    {
+        /// <summary>
+        /// Gets the horizontal gradient operator.
+        /// </summary>
+        public override float[,] KernelX => new float[,]
+        {
+            { -1, -1, -1 },
+            { -1,  8, -1 },
+            { -1, -1, -1 }
+        };
+    }
+}

src/ImageProcessor/Filters/Convolution/Laplacian5X5.cs

@@ -0,0 +1,26 @@
+// <copyright file="Laplacian5X5.cs" company="James South">
+// Copyright (c) James South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+
+namespace ImageProcessor.Filters
+{
+    /// <summary>
+    /// The Laplacian 5 x 5 operator filter.
+    /// <see href="http://en.wikipedia.org/wiki/Discrete_Laplace_operator"/>
+    /// </summary>
+    public class Laplacian5X5 : ConvolutionFilter
+    {
+        /// <summary>
+        /// Gets the horizontal gradient operator.
+        /// </summary>
+        public override float[,] KernelX => new float[,]
+        {
+            { -1, -1, -1, -1, -1 },
+            { -1, -1, -1, -1, -1 },
+            { -1, -1, 24, -1, -1 },
+            { -1, -1, -1, -1, -1 },
+            { -1, -1, -1, -1, -1 }
+        };
+    }
+}

src/ImageProcessor/Filters/Convolution/LaplacianOfGaussian.cs

@@ -0,0 +1,26 @@
+// <copyright file="LaplacianOfGaussian.cs" company="James South">
+// Copyright (c) James South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+
+namespace ImageProcessor.Filters
+{
+    /// <summary>
+    /// The Laplacian of Gaussian operator filter.
+    /// <see href="http://fourier.eng.hmc.edu/e161/lectures/gradient/node9.html"/>
+    /// </summary>
+    public class LaplacianOfGaussian : ConvolutionFilter
+    {
+        /// <summary>
+        /// Gets the horizontal gradient operator.
+        /// </summary>
+        public override float[,] KernelX => new float[,]
+        {
+            { 0, 0, -1,  0,  0 },
+            { 0, -1, -2, -1,  0 },
+            { -1, -2, 16, -2, -1 },
+            { 0, -1, -2, -1,  0 },
+            { 0, 0, -1,  0,  0 }
+        };
+    }
+}

src/ImageProcessor/Filters/Convolution/Prewitt.cs

@@ -0,0 +1,34 @@
+// <copyright file="Prewitt.cs" company="James South">
+// Copyright (c) James South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+
+namespace ImageProcessor.Filters
+{
+    /// <summary>
+    /// The Prewitt operator filter.
+    /// <see href="http://en.wikipedia.org/wiki/Prewitt_operator"/>
+    /// </summary>
+    public class Prewitt : Convolution2DFilter
+    {
+        /// <summary>
+        /// Gets the horizontal gradient operator.
+        /// </summary>
+        public override float[,] KernelX => new float[,]
+        {
+            { -1, 0, 1 },
+            { -1, 0, 1 },
+            { -1, 0, 1 }
+        };
+
+        /// <summary>
+        /// Gets the vertical gradient operator.
+        /// </summary>
+        public override float[,] KernelY => new float[,]
+        {
+            { 1, 1, 1 },
+            { 0, 0, 0 },
+            { -1, -1, -1 }
+        };
+    }
+}

src/ImageProcessor/Filters/Convolution/RobertsCross.cs

@@ -0,0 +1,32 @@
+// <copyright file="RobertsCross.cs" company="James South">
+// Copyright (c) James South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+
+namespace ImageProcessor.Filters
+{
+    /// <summary>
+    /// The Roberts Cross operator filter.
+    /// <see href="http://en.wikipedia.org/wiki/Roberts_cross"/>
+    /// </summary>
+    public class RobertsCross : Convolution2DFilter
+    {
+        /// <summary>
+        /// Gets the horizontal gradient operator.
+        /// </summary>
+        public override float[,] KernelX => new float[,]
+        {
+            { 1, 0 },
+            { 0, -1 }
+        };
+
+        /// <summary>
+        /// Gets the vertical gradient operator.
+        /// </summary>
+        public override float[,] KernelY => new float[,]
+        {
+            { 0, 1 },
+            { -1, 0 }
+        };
+    }
+}

src/ImageProcessor/Filters/Convolution/Scharr.cs

@@ -0,0 +1,34 @@
+// <copyright file="Scharr.cs" company="James South">
+// Copyright (c) James South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+
+namespace ImageProcessor.Filters
+{
+    /// <summary>
+    /// The Scharr operator filter.
+    /// <see href="http://en.wikipedia.org/wiki/Sobel_operator#Alternative_operators"/>
+    /// </summary>
+    public class Scharr : Convolution2DFilter
+    {
+        /// <summary>
+        /// Gets the horizontal gradient operator.
+        /// </summary>
+        public override float[,] KernelX => new float[,]
+        {
+            { -3, 0, 3 },
+            { -10, 0, 10 },
+            { -3, 0, 3 }
+        };
+
+        /// <summary>
+        /// Gets the vertical gradient operator.
+        /// </summary>
+        public override float[,] KernelY => new float[,]
+        {
+            { 3, 10, 3 },
+            { 0, 0, 0 },
+            { -3, -10, -3 }
+        };
+    }
+}

src/ImageProcessor/Filters/Convolution/Sobel.cs

@@ -0,0 +1,34 @@
+// <copyright file="Sobel.cs" company="James South">
+// Copyright (c) James South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+
+namespace ImageProcessor.Filters
+{
+    /// <summary>
+    /// The Sobel operator filter.
+    /// <see href="http://en.wikipedia.org/wiki/Sobel_operator"/>
+    /// </summary>
+    public class Sobel : Convolution2DFilter
+    {
+        /// <summary>
+        /// Gets the horizontal gradient operator.
+        /// </summary>
+        public override float[,] KernelX => new float[,]
+        {
+            { -1, 0, 1 },
+            { -2, 0, 2 },
+            { -1, 0, 1 }
+        };
+
+        /// <summary>
+        /// Gets the vertical gradient operator.
+        /// </summary>
+        public override float[,] KernelY => new float[,]
+        {
+            { 1, 2, 1 },
+            { 0, 0, 0 },
+            { -1, -2, -1 }
+        };
+    }
+}

src/ImageProcessor/ImageProcessor.csproj

@@ -49,11 +49,21 @@
     <Compile Include="Common\Helpers\ImageMaths.cs" />
     <Compile Include="Common\Helpers\PixelOperations.cs" />
     <Compile Include="Filters\Blend.cs" />
+    <Compile Include="Filters\Convolution\Convolution2DFilter.cs" />
     <Compile Include="Filters\ColorMatrix\ColorMatrixFilter.cs" />
     <Compile Include="Filters\ColorMatrix\Kodachrome.cs" />
     <Compile Include="Filters\ColorMatrix\Saturation.cs" />
     <Compile Include="Filters\ColorMatrix\GreyscaleMode.cs" />
     <Compile Include="Filters\Brightness.cs" />
+    <Compile Include="Filters\Convolution\Scharr.cs" />
+    <Compile Include="Filters\Convolution\RobertsCross.cs" />
+    <Compile Include="Filters\Convolution\Prewitt.cs" />
+    <Compile Include="Filters\Convolution\LaplacianOfGaussian.cs" />
+    <Compile Include="Filters\Convolution\Laplacian3X3.cs" />
+    <Compile Include="Filters\Convolution\Laplacian5X5.cs" />
+    <Compile Include="Filters\Convolution\Kirsch.cs" />
+    <Compile Include="Filters\Convolution\Kayyali.cs" />
+    <Compile Include="Filters\Convolution\Sobel.cs" />
     <Compile Include="Filters\Invert.cs" />
     <Compile Include="Filters\Alpha.cs" />
     <Compile Include="Filters\ColorMatrix\GreyscaleBt601.cs" />
@@ -220,6 +230,7 @@
     <Compile Include="Numerics\Point.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Numerics\Size.cs" />
+    <Compile Include="Filters\Convolution\ConvolutionFilter.cs" />
     <Compile Include="Samplers\Resamplers\Lanczos5Resampler.cs" />
     <Compile Include="Samplers\Resamplers\Lanczos8Resampler.cs" />
     <Compile Include="Samplers\Resamplers\WelchResampler.cs" />
@@ -251,6 +262,7 @@
   <ItemGroup>
     <AdditionalFiles Include="stylecop.json" />
   </ItemGroup>
+  <ItemGroup />
   <Import Project="$(MSBuildExtensionsPath32)\Microsoft\Portable\$(TargetFrameworkVersion)\Microsoft.Portable.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.

src/ImageProcessor/ImageProcessor.csproj.DotSettings

@@ -8,6 +8,7 @@
 	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=common_005Chelpers/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=encoders_005Cgif/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=filters_005Ccolormatrix/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=filters_005Cconvolution/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=formats_005Cbmp/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=formats_005Cgif/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=formats_005Cgif_005Cquantizer/@EntryIndexedValue">True</s:Boolean>

src/ImageProcessor/project.lock.json.REMOVED.git-id

@@ -1 +1 @@
-eb00c54ee74016c2b70f81963e7e8f83cb2dd54b
+3f05708641eb3ed085d4689aae4a960eb067fd16

tests/ImageProcessor.Tests/Processors/Filters/FilterTests.cs

@@ -16,7 +16,7 @@ namespace ImageProcessor.Tests
             //{ "Brightness--50", new Brightness(-50) },
             //{ "Contrast-50", new Contrast(50) },
             //{ "Contrast--50", new Contrast(-50) },
-            { "Blend", new Blend(new Image(File.OpenRead("../../TestImages/Formats/Bmp/Car.bmp")),75)},
+            //{ "Blend", new Blend(new Image(File.OpenRead("../../TestImages/Formats/Bmp/Car.bmp")),15)},
             //{ "Saturation-50", new Saturation(50) },
             //{ "Saturation--50", new Saturation(-50) },
             //{ "Alpha--50", new Alpha(50) },
@@ -27,7 +27,16 @@ namespace ImageProcessor.Tests
             //{ "Polaroid", new Polaroid() },
             //{ "Kodachrome", new Kodachrome() },
             //{ "GreyscaleBt709", new GreyscaleBt709() },
-            //{ "GreyscaleBt601", new GreyscaleBt601() },
+            //{ "GreyscaleBt601", new GreyscaleBt601() },`
+            { "Kayyali", new Kayyali() },
+            { "Kirsch", new Kirsch() },
+            { "Laplacian3X3", new Laplacian3X3() },
+            { "Laplacian5X5", new Laplacian5X5() },
+            { "LaplacianOfGaussian", new LaplacianOfGaussian() },
+            { "Prewitt", new Prewitt() },
+            { "RobertsCross", new RobertsCross() },
+            { "Scharr", new Scharr() },
+            { "Sobel", new Sobel() }
         };
 
         [Theory]