Refactor edge detection to streamline API

Former-commit-id: 9e5b8edfb049780f3f8a553f02b2fee20b29f91d
Former-commit-id: 66241f9dd5f8be909f03d8b6435e86f69b3f95d4
Former-commit-id: b34b5df5f557b528d9dcea49e92d93532b984cb6

ImageProcessor.sln.DotSettings

@@ -0,0 +1,2 @@
+<wpf:ResourceDictionary xml:space="preserve" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:ss="urn:shemas-jetbrains-com:settings-storage-xaml" xmlns:wpf="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
+	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/Abbreviations/=XY/@EntryIndexedValue">XY</s:String></wpf:ResourceDictionary>

src/ImageProcessor/Filters/ColorMatrix/IColorMatrixFilter.cs

@@ -11,7 +11,7 @@ namespace ImageProcessor.Filters
     /// Encapsulates properties and methods for creating processors that utilize a matrix to
     /// alter the image pixels.
     /// </summary>
-    public interface IColorMatrixFilter
+    public interface IColorMatrixFilter : IImageProcessor
     {
         /// <summary>
         /// Gets the <see cref="Matrix4x4"/> used to alter the image.

src/ImageProcessor/Filters/ColorMatrix/Saturation.cs

@@ -40,7 +40,7 @@ namespace ImageProcessor.Filters
         public override Matrix4x4 Matrix => this.matrix;
 
         /// <inheritdoc/>
-        protected override void OnApply(Rectangle targetRectangle, Rectangle sourceRectangle)
+        protected override void OnApply(ImageBase source, Rectangle targetRectangle, Rectangle sourceRectangle)
         {
             float saturationFactor = this.saturation / 100f;
 

src/ImageProcessor/Filters/Convolution/Convolution2DFilter.cs

@@ -9,7 +9,7 @@ namespace ImageProcessor.Filters
     using System.Threading.Tasks;
 
     /// <summary>
-    /// Defines a filter that uses a matrix to perform convolution across two dimensions against an image.
+    /// Defines a filter that uses two one-dimensional matrices to perform convolution against an image.
     /// </summary>
     public abstract class Convolution2DFilter : ParallelImageProcessor
     {

src/ImageProcessor/Filters/Convolution/Convolution2PassFilter.cs

@@ -8,7 +8,7 @@ namespace ImageProcessor.Filters
     using System.Threading.Tasks;
 
     /// <summary>
-    /// Defines a filter that uses a matrix to perform convolution across two dimensions against an image.
+    /// Defines a filter that uses two one-dimensional matrices to perform two-pass convolution against an image.
     /// </summary>
     public abstract class Convolution2PassFilter : ParallelImageProcessor
     {

src/ImageProcessor/Filters/Convolution/ConvolutionFilter.cs

@@ -8,19 +8,19 @@ 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.
+    /// Defines a filter that uses a 2 dimensional matrix to perform convolution against an image.
     /// </summary>
     public abstract class ConvolutionFilter : ParallelImageProcessor
     {
         /// <summary>
-        /// Gets the horizontal gradient operator.
+        /// Gets the 2d gradient operator.
         /// </summary>
-        public abstract float[,] KernelX { get; }
+        public abstract float[,] KernelXY { get; }
 
         /// <inheritdoc/>
         protected override void Apply(ImageBase target, ImageBase source, Rectangle targetRectangle, Rectangle sourceRectangle, int startY, int endY)
         {
-            float[,] kernelX = this.KernelX;
+            float[,] kernelX = this.KernelXY;
             int kernelLength = kernelX.GetLength(0);
             int radius = kernelLength >> 1;
 

src/ImageProcessor/Filters/Convolution/EdgeDetection/EdgeDetector2DFilter.cs

@@ -0,0 +1,26 @@
+// <copyright file="EdgeDetector2DFilter.cs" company="James South">
+// Copyright (c) James South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+
+namespace ImageProcessor.Filters
+{
+    /// <summary>
+    /// Defines a filter that detects edges within an image using two
+    /// one-dimensional matrices.
+    /// </summary>
+    public abstract class EdgeDetector2DFilter : Convolution2DFilter, IEdgeDetectorFilter
+    {
+        /// <inheritdoc/>
+        public bool Greyscale { get; set; }
+
+        /// <inheritdoc/>
+        protected override void OnApply(ImageBase source, Rectangle targetRectangle, Rectangle sourceRectangle)
+        {
+            if (this.Greyscale)
+            {
+                new GreyscaleBt709().Apply(source, source, sourceRectangle);
+            }
+        }
+    }
+}

src/ImageProcessor/Filters/Convolution/EdgeDetection/EdgeDetectorFilter.cs

@@ -0,0 +1,26 @@
+// <copyright file="EdgeDetectorFilter.cs" company="James South">
+// Copyright (c) James South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+
+namespace ImageProcessor.Filters
+{
+    /// <summary>
+    /// Defines a filter that detects edges within an image using a single
+    /// two dimensional matrix.
+    /// </summary>
+    public abstract class EdgeDetectorFilter : ConvolutionFilter, IEdgeDetectorFilter
+    {
+        /// <inheritdoc/>
+        public bool Greyscale { get; set; }
+
+        /// <inheritdoc/>
+        protected override void OnApply(ImageBase source, Rectangle targetRectangle, Rectangle sourceRectangle)
+        {
+            if (this.Greyscale)
+            {
+                new GreyscaleBt709().Apply(source, source, sourceRectangle);
+            }
+        }
+    }
+}

src/ImageProcessor/Filters/Convolution/EdgeDetection/IEdgeDetectorFilter.cs

@@ -0,0 +1,19 @@
+// <copyright file="IEdgeDetectorFilter.cs" company="James South">
+// Copyright (c) James South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+
+namespace ImageProcessor.Filters
+{
+    /// <summary>
+    /// Provides properties and methods allowing the detection of edges within an image.
+    /// </summary>
+    public interface IEdgeDetectorFilter : IImageProcessor
+    {
+        /// <summary>
+        /// Gets or sets a value indicating whether to convert the
+        /// image to greyscale before performing edge detection.
+        /// </summary>
+        bool Greyscale { get; set; }
+    }
+}

src/ImageProcessor/Filters/Convolution/EdgeDetection/Kayyali.cs

@@ -9,11 +9,9 @@ namespace ImageProcessor.Filters
     /// The Kayyali operator filter.
     /// <see href="http://edgedetection.webs.com/"/>
     /// </summary>
-    public class Kayyali : Convolution2DFilter
+    public class Kayyali : EdgeDetector2DFilter
     {
-        /// <summary>
-        /// Gets the horizontal gradient operator.
-        /// </summary>
+        /// <inheritdoc/>
         public override float[,] KernelX => new float[,]
         {
             { 6, 0, -6 },
@@ -21,9 +19,7 @@ namespace ImageProcessor.Filters
             { -6, 0, 6 }
         };
 
-        /// <summary>
-        /// Gets the vertical gradient operator.
-        /// </summary>
+        /// <inheritdoc/>
         public override float[,] KernelY => new float[,]
         {
             { -6, 0, 6 },

src/ImageProcessor/Filters/Convolution/EdgeDetection/Kirsch.cs

@@ -9,11 +9,9 @@ namespace ImageProcessor.Filters
     /// The Kirsch operator filter.
     /// <see href="http://en.wikipedia.org/wiki/Kirsch_operator"/>
     /// </summary>
-    public class Kirsch : Convolution2DFilter
+    public class Kirsch : EdgeDetector2DFilter
     {
-        /// <summary>
-        /// Gets the horizontal gradient operator.
-        /// </summary>
+        /// <inheritdoc/>
         public override float[,] KernelX => new float[,]
         {
             { 5, 5, 5 },
@@ -21,9 +19,7 @@ namespace ImageProcessor.Filters
             { -3, -3, -3 }
         };
 
-        /// <summary>
-        /// Gets the vertical gradient operator.
-        /// </summary>
+        /// <inheritdoc/>
         public override float[,] KernelY => new float[,]
         {
             { 5, -3, -3 },

src/ImageProcessor/Filters/Convolution/EdgeDetection/Laplacian3X3.cs

@@ -9,12 +9,10 @@ namespace ImageProcessor.Filters
     /// The Laplacian 3 x 3 operator filter.
     /// <see href="http://en.wikipedia.org/wiki/Discrete_Laplace_operator"/>
     /// </summary>
-    public class Laplacian3X3 : ConvolutionFilter
+    public class Laplacian3X3 : EdgeDetectorFilter
     {
-        /// <summary>
-        /// Gets the horizontal gradient operator.
-        /// </summary>
-        public override float[,] KernelX => new float[,]
+        /// <inheritdoc/>
+        public override float[,] KernelXY => new float[,]
         {
             { -1, -1, -1 },
             { -1,  8, -1 },

src/ImageProcessor/Filters/Convolution/EdgeDetection/Laplacian5X5.cs

@@ -9,12 +9,10 @@ namespace ImageProcessor.Filters
     /// The Laplacian 5 x 5 operator filter.
     /// <see href="http://en.wikipedia.org/wiki/Discrete_Laplace_operator"/>
     /// </summary>
-    public class Laplacian5X5 : ConvolutionFilter
+    public class Laplacian5X5 : EdgeDetectorFilter
     {
-        /// <summary>
-        /// Gets the horizontal gradient operator.
-        /// </summary>
-        public override float[,] KernelX => new float[,]
+        /// <inheritdoc/>
+        public override float[,] KernelXY => new float[,]
         {
             { -1, -1, -1, -1, -1 },
             { -1, -1, -1, -1, -1 },

src/ImageProcessor/Filters/Convolution/EdgeDetection/LaplacianOfGaussian.cs

@@ -7,14 +7,12 @@ namespace ImageProcessor.Filters
 {
     /// <summary>
     /// The Laplacian of Gaussian operator filter.
-    /// <see href="http://fourier.eng.hmc.edu/e161/lectures/gradient/node9.html"/>
+    /// <see href="http://fourier.eng.hmc.edu/e161/lectures/gradient/node8.html"/>
     /// </summary>
-    public class LaplacianOfGaussian : ConvolutionFilter
+    public class LaplacianOfGaussian : EdgeDetectorFilter
     {
-        /// <summary>
-        /// Gets the horizontal gradient operator.
-        /// </summary>
-        public override float[,] KernelX => new float[,]
+        /// <inheritdoc/>
+        public override float[,] KernelXY => new float[,]
         {
             { 0, 0, -1,  0,  0 },
             { 0, -1, -2, -1,  0 },

src/ImageProcessor/Filters/Convolution/EdgeDetection/Prewitt.cs

@@ -9,11 +9,9 @@ namespace ImageProcessor.Filters
     /// The Prewitt operator filter.
     /// <see href="http://en.wikipedia.org/wiki/Prewitt_operator"/>
     /// </summary>
-    public class Prewitt : Convolution2DFilter
+    public class Prewitt : EdgeDetector2DFilter
     {
-        /// <summary>
-        /// Gets the horizontal gradient operator.
-        /// </summary>
+        /// <inheritdoc/>
         public override float[,] KernelX => new float[,]
         {
             { -1, 0, 1 },
@@ -21,14 +19,15 @@ namespace ImageProcessor.Filters
             { -1, 0, 1 }
         };
 
-        /// <summary>
-        /// Gets the vertical gradient operator.
-        /// </summary>
+        /// <inheritdoc/>
         public override float[,] KernelY => new float[,]
         {
             { 1, 1, 1 },
             { 0, 0, 0 },
             { -1, -1, -1 }
         };
+
+        /// <inheritdoc/>
+        public bool Greyscale { get; set; }
     }
 }

src/ImageProcessor/Filters/Convolution/EdgeDetection/RobertsCross.cs

@@ -9,20 +9,16 @@ namespace ImageProcessor.Filters
     /// The Roberts Cross operator filter.
     /// <see href="http://en.wikipedia.org/wiki/Roberts_cross"/>
     /// </summary>
-    public class RobertsCross : Convolution2DFilter
+    public class RobertsCross : EdgeDetector2DFilter
     {
-        /// <summary>
-        /// Gets the horizontal gradient operator.
-        /// </summary>
+        /// <inheritdoc/>
         public override float[,] KernelX => new float[,]
         {
             { 1, 0 },
             { 0, -1 }
         };
 
-        /// <summary>
-        /// Gets the vertical gradient operator.
-        /// </summary>
+        /// <inheritdoc/>
         public override float[,] KernelY => new float[,]
         {
             { 0, 1 },

src/ImageProcessor/Filters/Convolution/EdgeDetection/Scharr.cs

@@ -9,11 +9,9 @@ namespace ImageProcessor.Filters
     /// The Scharr operator filter.
     /// <see href="http://en.wikipedia.org/wiki/Sobel_operator#Alternative_operators"/>
     /// </summary>
-    public class Scharr : Convolution2DFilter
+    public class Scharr : EdgeDetector2DFilter
     {
-        /// <summary>
-        /// Gets the horizontal gradient operator.
-        /// </summary>
+        /// <inheritdoc/>
         public override float[,] KernelX => new float[,]
         {
             { -3, 0, 3 },
@@ -21,9 +19,7 @@ namespace ImageProcessor.Filters
             { -3, 0, 3 }
         };
 
-        /// <summary>
-        /// Gets the vertical gradient operator.
-        /// </summary>
+        /// <inheritdoc/>
         public override float[,] KernelY => new float[,]
         {
             { 3, 10, 3 },

src/ImageProcessor/Filters/Convolution/EdgeDetection/Sobel.cs

@@ -9,11 +9,9 @@ namespace ImageProcessor.Filters
     /// The Sobel operator filter.
     /// <see href="http://en.wikipedia.org/wiki/Sobel_operator"/>
     /// </summary>
-    public class Sobel : Convolution2DFilter
+    public class Sobel : EdgeDetector2DFilter
     {
-        /// <summary>
-        /// Gets the horizontal gradient operator.
-        /// </summary>
+        /// <inheritdoc/>
         public override float[,] KernelX => new float[,]
         {
             { -1, 0, 1 },
@@ -21,9 +19,7 @@ namespace ImageProcessor.Filters
             { -1, 0, 1 }
         };
 
-        /// <summary>
-        /// Gets the vertical gradient operator.
-        /// </summary>
+        /// <inheritdoc/>
         public override float[,] KernelY => new float[,]
         {
             { 1, 2, 1 },

src/ImageProcessor/Filters/Convolution/GuassianBlur.cs

@@ -82,7 +82,7 @@ namespace ImageProcessor.Filters
         public override int Parallelism => 1;
 
         /// <inheritdoc/>
-        protected override void OnApply(Rectangle targetRectangle, Rectangle sourceRectangle)
+        protected override void OnApply(ImageBase source, Rectangle targetRectangle, Rectangle sourceRectangle)
         {
             if (this.kernelY == null)
             {

src/ImageProcessor/Filters/Convolution/GuassianSharpen.cs

@@ -82,7 +82,7 @@ namespace ImageProcessor.Filters
         public override int Parallelism => 1;
 
         /// <inheritdoc/>
-        protected override void OnApply(Rectangle targetRectangle, Rectangle sourceRectangle)
+        protected override void OnApply(ImageBase source, Rectangle targetRectangle, Rectangle sourceRectangle)
         {
             if (this.kernelY == null)
             {

src/ImageProcessor/Filters/ImageFilterExtensions.cs

@@ -135,6 +135,42 @@ namespace ImageProcessor.Filters
             return source.Process(rectangle, new Contrast(amount));
         }
 
+        /// <summary>
+        /// Detects any edges within the image. Uses the <see cref="Sobel"/> filter
+        /// operating in greyscale mode.
+        /// </summary>
+        /// <param name="source">The image this method extends.</param>
+        /// <returns>The <see cref="Image"/>.</returns>
+        public static Image DetectEdges(this Image source)
+        {
+            return DetectEdges(source, source.Bounds, new Sobel { Greyscale = true });
+        }
+
+        /// <summary>
+        /// Detects any edges within the image.
+        /// </summary>
+        /// <param name="source">The image this method extends.</param>
+        /// <param name="filter">The filter for detecting edges.</param>
+        /// <returns>The <see cref="Image"/>.</returns>
+        public static Image DetectEdges(this Image source, IEdgeDetectorFilter filter)
+        {
+            return DetectEdges(source, source.Bounds, filter);
+        }
+
+        /// <summary>
+        /// Detects any edges within the image.
+        /// </summary>
+        /// <param name="source">The image this method extends.</param>
+        /// <param name="rectangle">
+        /// The <see cref="Rectangle"/> structure that specifies the portion of the image object to alter.
+        /// </param>
+        /// <param name="filter">The filter for detecting edges.</param>
+        /// <returns>The <see cref="Image"/>.</returns>
+        public static Image DetectEdges(this Image source, Rectangle rectangle, IEdgeDetectorFilter filter)
+        {
+            return source.Process(rectangle, filter);
+        }
+
         /// <summary>
         /// Applies greyscale toning to the image.
         /// </summary>

src/ImageProcessor/Formats/Gif/Quantizer/OctreeQuantizer.cs

@@ -8,8 +8,6 @@ namespace ImageProcessor.Formats
     using System;
     using System.Collections.Generic;
 
-    using ImageProcessor.Common.Extensions;
-
     /// <summary>
     /// Encapsulates methods to calculate the colour palette if an image using an Octree pattern.
     /// <see href="http://msdn.microsoft.com/en-us/library/aa479306.aspx"/>

src/ImageProcessor/ImageProcessor.csproj

@@ -57,6 +57,9 @@
     <Compile Include="Filters\ColorMatrix\Saturation.cs" />
     <Compile Include="Filters\ColorMatrix\GreyscaleMode.cs" />
     <Compile Include="Filters\Brightness.cs" />
+    <Compile Include="Filters\Convolution\EdgeDetection\EdgeDetector2DFilter.cs" />
+    <Compile Include="Filters\Convolution\EdgeDetection\EdgeDetectorFilter.cs" />
+    <Compile Include="Filters\Convolution\EdgeDetection\IEdgeDetectorFilter.cs" />
     <Compile Include="Filters\Convolution\EdgeDetection\Scharr.cs" />
     <Compile Include="Filters\Convolution\EdgeDetection\RobertsCross.cs" />
     <Compile Include="Filters\Convolution\EdgeDetection\Prewitt.cs" />

src/ImageProcessor/ParallelImageProcessor.cs

@@ -21,7 +21,7 @@ namespace ImageProcessor
         /// <inheritdoc/>
         public void Apply(ImageBase target, ImageBase source, Rectangle sourceRectangle)
         {
-            this.OnApply(target.Bounds, sourceRectangle);
+            this.OnApply(source, target.Bounds, sourceRectangle);
 
             if (this.Parallelism > 1)
             {
@@ -66,7 +66,7 @@ namespace ImageProcessor
                 sourceRectangle = source.Bounds;
             }
 
-            this.OnApply(target.Bounds, sourceRectangle);
+            this.OnApply(source, target.Bounds, sourceRectangle);
 
             if (this.Parallelism > 1)
             {
@@ -98,6 +98,7 @@ namespace ImageProcessor
         /// <summary>
         /// This method is called before the process is applied to prepare the processor.
         /// </summary>
+        /// <param name="source">The source image. Cannot be null.</param>
         /// <param name="targetRectangle">
         /// The <see cref="Rectangle"/> structure that specifies the location and size of the drawn image.
         /// The image is scaled to fit the rectangle.
@@ -105,7 +106,7 @@ namespace ImageProcessor
         /// <param name="sourceRectangle">
         /// The <see cref="Rectangle"/> structure that specifies the portion of the image object to draw.
         /// </param>
-        protected virtual void OnApply(Rectangle targetRectangle, Rectangle sourceRectangle)
+        protected virtual void OnApply(ImageBase source, Rectangle targetRectangle, Rectangle sourceRectangle)
         {
         }
 

src/ImageProcessor/Samplers/Resize.cs

@@ -48,7 +48,7 @@ namespace ImageProcessor.Samplers
         public IResampler Sampler { get; }
 
         /// <inheritdoc/>
-        protected override void OnApply(Rectangle targetRectangle, Rectangle sourceRectangle)
+        protected override void OnApply(ImageBase source, Rectangle targetRectangle, Rectangle sourceRectangle)
         {
             this.horizontalWeights = this.PrecomputeWeights(targetRectangle.Width, sourceRectangle.Width);
             this.verticalWeights = this.PrecomputeWeights(targetRectangle.Height, sourceRectangle.Height);

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

@@ -37,7 +37,7 @@ namespace ImageProcessor.Tests
             { "Prewitt", new Prewitt() },
             { "RobertsCross", new RobertsCross() },
             { "Scharr", new Scharr() },
-            { "Sobel", new Sobel() },
+            { "Sobel", new Sobel {Greyscale = true} },
             { "GuassianBlur", new GuassianBlur(10) },
             { "GuassianSharpen", new GuassianSharpen(10) }
         };