Adding replace color functionality

Former-commit-id: 47ef8ddfa95092974213c3312125f5b171f7a2f3

src/ImageProcessor/ImageFactory.cs

@@ -660,7 +660,7 @@ namespace ImageProcessor
         /// </returns>
         public ImageFactory Quality(int percentage)
         {
-            if (this.ShouldProcess)
+            if (percentage <= 100 && percentage >= 0 && this.ShouldProcess)
             {
                 this.CurrentImageFormat.Quality = percentage;
             }
@@ -668,6 +668,41 @@ namespace ImageProcessor
             return this;
         }
 
+        /// <summary>
+        /// Replaces a color within the current image.
+        /// </summary>
+        /// <param name="target">
+        /// The target <see cref="System.Drawing.Color"/>.
+        /// </param>
+        /// <param name="replacement">
+        /// The replacement <see cref="System.Drawing.Color"/>.
+        /// </param>
+        /// <param name="fuzziness">
+        /// A value between 0 and 100 with which to alter the target detection accuracy.
+        /// </param>
+        /// <returns>
+        /// The <see cref="ImageFactory"/>.
+        /// </returns>
+        public ImageFactory ReplaceColor(Color target, Color replacement, int fuzziness = 0)
+        {
+            // Sanitize the input.
+            if (fuzziness < 0 || fuzziness > 100)
+            {
+                fuzziness = 0;
+            }
+
+            if (this.ShouldProcess && target != Color.Empty && replacement != Color.Empty)
+            {
+                ReplaceColor replaceColor = new ReplaceColor
+                {
+                    DynamicParameter = new Tuple<Color, Color, int>(target, replacement, fuzziness)
+                };
+                this.CurrentImageFormat.ApplyProcessor(replaceColor.ProcessImage, this);
+            }
+
+            return this;
+        }
+
         /// <summary>
         /// Resizes the current image to the given dimensions.
         /// </summary>

src/ImageProcessor/ImageProcessor.csproj

@@ -128,6 +128,7 @@
     <Compile Include="Processors\Hue.cs" />
     <Compile Include="Processors\Meta.cs" />
     <Compile Include="Processors\Pixelate.cs" />
+    <Compile Include="Processors\ReplaceColor.cs" />
     <Compile Include="Processors\RoundedCorners.cs" />
     <Compile Include="Processors\Saturation.cs" />
     <Compile Include="Processors\Flip.cs" />

src/ImageProcessor/Processors/ReplaceColor.cs

@@ -1,14 +1,24 @@
-namespace ImageProcessor.Processors
+// --------------------------------------------------------------------------------------------------------------------
+// <copyright file="ReplaceColor.cs" company="James South">
+//   Copyright (c) James South.
+//   Licensed under the Apache License, Version 2.0.
+// </copyright>
+// <summary>
+//   Encapsulates methods allowing the replacement of a color within an image.
+// </summary>
+// --------------------------------------------------------------------------------------------------------------------
+
+namespace ImageProcessor.Processors
 {
     using System;
     using System.Collections.Generic;
     using System.Drawing;
     using ImageProcessor.Common.Exceptions;
+    using ImageProcessor.Common.Extensions;
     using ImageProcessor.Imaging;
 
     /// <summary>
     /// Encapsulates methods allowing the replacement of a color within an image.
-    /// <see href="http://softwarebydefault.com/2013/03/16/bitmap-color-substitution/"/>
     /// </summary>
     public class ReplaceColor : IGraphicsProcessor
     {
@@ -57,20 +67,55 @@
             {
                 Tuple<Color, Color, int> parameters = this.DynamicParameter;
                 Color original = parameters.Item1;
+                byte originalR = original.R;
+                byte originalG = original.G;
+                byte originalB = original.B;
+
                 Color replacement = parameters.Item2;
-                int threshold = parameters.Item3;
+                byte replacementR = original.R;
+                byte replacementG = replacement.G;
+                byte replacementB = replacement.B;
+
+                int fuzziness = parameters.Item3;
 
                 newImage = new Bitmap(image);
+                int width = image.Width;
+                int height = image.Height;
 
                 using (FastBitmap fastBitmap = new FastBitmap(newImage))
                 {
-                    
+                    for (int x = 0; x < width; x++)
+                    {
+                        for (int y = 0; y < height; y++)
+                        {
+                            // Get the pixel color.
+                            Color currentColor = fastBitmap.GetPixel(x, y);
+                            byte currentR = currentColor.R;
+                            byte currentG = currentColor.B;
+                            byte currentB = currentColor.B;
 
+                            // Test whether it is in the expected range.
+                            if (currentR <= originalR + fuzziness && currentR >= originalR - fuzziness)
+                            {
+                                if (currentG <= originalG + fuzziness && currentG >= originalG - fuzziness)
+                                {
+                                    if (currentB <= originalB + fuzziness && currentB >= originalB - fuzziness)
+                                    {
+                                        // Ensure the values are withing an acceptable byte range
+                                        // and set the new value.
+                                        byte r = (originalR - currentR + replacementR).ToByte();
+                                        byte g = (originalG - currentG + replacementG).ToByte();
+                                        byte b = (originalB - currentB + replacementB).ToByte();
+                                        fastBitmap.SetPixel(x, y, Color.FromArgb(currentColor.A, r, g, b));
+                                    }
+                                }
+                            }
+                        }
+                    }
                 }
 
                 image.Dispose();
                 image = newImage;
-
             }
             catch (Exception ex)
             {

src/ImageProcessorConsole/Program.cs

@@ -74,7 +74,8 @@ namespace ImageProcessorConsole
                             //.Resize(new Size((int)(size.Width * 1.1), 0))
                             //.ContentAwareResize(layer)
                             .Constrain(size)
-                            .Filter(MatrixFilters.Comic)
+                            .ReplaceColor(Color.FromArgb(255, 1, 107, 165), Color.FromArgb(255, 1, 165, 13), 80)
+                            //.Filter(MatrixFilters.Comic)
                             //.Filter(MatrixFilters.HiSatch)
                             //.Pixelate(8)
                             //.GaussianSharpen(10)