Moar optimisations plus start tidy up

Former-commit-id: 98655c0fccf43335504a97036f9fc699c490af17
Former-commit-id: 002b3f569e94bd36357de09271033cf033ed3997

src/ImageProcessor/ImageProcessor.csproj

@@ -185,14 +185,12 @@
     <Compile Include="Imaging\Quantizers\OctreeQuantizer.cs" />
     <Compile Include="Imaging\Quantizers\Quantizer.cs" />
     <Compile Include="Imaging\Quantizers\WuQuantizer\Box.cs" />
-    <Compile Include="Imaging\Quantizers\WuQuantizer\PaletteLookup.cs" />
-    <Compile Include="Imaging\Quantizers\WuQuantizer\PaletteBuffer.cs" />
-    <Compile Include="Imaging\Quantizers\WuQuantizer\ColorData.cs" />
     <Compile Include="Imaging\Quantizers\WuQuantizer\ColorMoment.cs" />
+    <Compile Include="Imaging\Quantizers\WuQuantizer\PaletteColorHistory.cs" />
+    <Compile Include="Imaging\Quantizers\WuQuantizer\PaletteLookup.cs" />
     <Compile Include="Imaging\Quantizers\WuQuantizer\CubeCut.cs" />
     <Compile Include="Imaging\Quantizers\WuQuantizer\ImageBuffer.cs" />
     <Compile Include="Imaging\Quantizers\WuQuantizer\IWuQuantizer.cs" />
-    <Compile Include="Imaging\Quantizers\WuQuantizer\Lookup.cs" />
     <Compile Include="Imaging\Quantizers\WuQuantizer\Pixel.cs">
       <SubType>Code</SubType>
     </Compile>

src/ImageProcessor/Imaging/Formats/PngFormat.cs

@@ -16,8 +16,7 @@ namespace ImageProcessor.Imaging.Formats
 
     using ImageProcessor.Common.Extensions;
     using ImageProcessor.Imaging.Quantizers;
-
-    using nQuant;
+    using ImageProcessor.Imaging.Quantizers.WuQuantizer;
 
     /// <summary>
     /// Provides the necessary information to support png images.

src/ImageProcessor/Imaging/Quantizers/WuQuantizer/Box.cs

@@ -1,15 +1,65 @@
-namespace nQuant
+// --------------------------------------------------------------------------------------------------------------------
+// <copyright file="Box.cs" company="James South">
+//   Copyright (c) James South.
+//   Licensed under the Apache License, Version 2.0.
+// </copyright>
+// <summary>
+//   The box for storing color attributes.
+//   Adapted from <see href="https://github.com/drewnoakes" />
+// </summary>
+// --------------------------------------------------------------------------------------------------------------------
+
+namespace ImageProcessor.Imaging.Quantizers.WuQuantizer
 {
+    /// <summary>
+    /// The box for storing color attributes.
+    /// Adapted from <see href="https://github.com/drewnoakes"/>
+    /// </summary>
     public struct Box
     {
-        public byte AlphaMinimum;
+        /// <summary>
+        /// The alpha maximum.
+        /// </summary>
         public byte AlphaMaximum;
-        public byte RedMinimum;
-        public byte RedMaximum;
-        public byte GreenMinimum;
-        public byte GreenMaximum;
-        public byte BlueMinimum;
+
+        /// <summary>
+        /// The alpha minimum.
+        /// </summary>
+        public byte AlphaMinimum;
+
+        /// <summary>
+        /// The blue maximum.
+        /// </summary>
         public byte BlueMaximum;
+
+        /// <summary>
+        /// The blue minimum.
+        /// </summary>
+        public byte BlueMinimum;
+
+        /// <summary>
+        /// The green maximum.
+        /// </summary>
+        public byte GreenMaximum;
+
+        /// <summary>
+        /// The green minimum.
+        /// </summary>
+        public byte GreenMinimum;
+
+        /// <summary>
+        /// The red maximum.
+        /// </summary>
+        public byte RedMaximum;
+
+        /// <summary>
+        /// The red minimum.
+        /// </summary>
+        public byte RedMinimum;
+
+        /// <summary>
+        /// The size.
+        /// </summary>
         public int Size;
     }
 }

src/ImageProcessor/Imaging/Quantizers/WuQuantizer/ColorData.cs

@@ -1,33 +0,0 @@
-// --------------------------------------------------------------------------------------------------------------------
-// <copyright file="ColorData.cs" company="James South">
-//   Copyright (c) James South.
-//   Licensed under the Apache License, Version 2.0.
-// </copyright>
-// --------------------------------------------------------------------------------------------------------------------
-
-namespace nQuant
-{
-    /// <summary>
-    /// The color data.
-    /// </summary>
-    public class ColorData
-    {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="ColorData"/> class.
-        /// </summary>
-        /// <param name="dataGranularity">
-        /// The data granularity.
-        /// </param>
-        public ColorData(int dataGranularity)
-        {
-            dataGranularity++;
-
-            this.Moments = new ColorMoment[dataGranularity, dataGranularity, dataGranularity, dataGranularity];
-        }
-
-        /// <summary>
-        /// Gets the moments.
-        /// </summary>
-        public ColorMoment[, , ,] Moments { get; private set; }
-    }
-}

src/ImageProcessor/Imaging/Quantizers/WuQuantizer/ColorMoment.cs

@@ -1,7 +1,8 @@
-
-namespace nQuant
+//using System.Runtime.CompilerServices;
+
+namespace ImageProcessor.Imaging.Quantizers.WuQuantizer
 {
-    public struct ColorMoment
+    struct ColorMoment
     {
         public long Alpha;
         public long Red;
@@ -43,16 +44,22 @@ namespace nQuant
             return c1;
         }
 
+        //[MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void Add(Pixel p)
         {
-            Alpha += p.Alpha;
-            Red += p.Red;
-            Green += p.Green;
-            Blue += p.Blue;
+            byte pAlpha = p.Alpha;
+            byte pRed = p.Red;
+            byte pGreen = p.Green;
+            byte pBlue = p.Blue;
+            Alpha += pAlpha;
+            Red += pRed;
+            Green += pGreen;
+            Blue += pBlue;
             Weight++;
-            Moment += p.Amplitude();
+            Moment += pAlpha * pAlpha + pRed * pRed + pGreen * pGreen + pBlue * pBlue;
         }
 
+        //[MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void AddFast(ref ColorMoment c2)
         {
             Alpha += c2.Alpha;
@@ -62,21 +69,21 @@ namespace nQuant
             Weight += c2.Weight;
             Moment += c2.Moment;
         }
-        
+
         public long Amplitude()
         {
-            return (Alpha * Alpha) + (Red * Red) + (Green * Green) + (Blue * Blue);
+            return Alpha * Alpha + Red * Red + Green * Green + Blue * Blue;
         }
 
         public long WeightedDistance()
         {
-            return this.Amplitude() / Weight;
+            return Amplitude() / Weight;
         }
 
         public float Variance()
         {
-            var result = Moment - ((float)this.Amplitude() / this.Weight);
+            var result = Moment - (float)Amplitude() / Weight;
             return float.IsNaN(result) ? 0.0f : result;
         }
     }
-}
+}

src/ImageProcessor/Imaging/Quantizers/WuQuantizer/CubeCut.cs

@@ -1,14 +1,45 @@
-namespace nQuant
+// --------------------------------------------------------------------------------------------------------------------
+// <copyright file="CubeCut.cs" company="James South">
+//   Copyright (c) James South.
+//   Licensed under the Apache License, Version 2.0.
+// </copyright>
+// <summary>
+//   Represents a cube cut.
+//   Adapted from <see href="https://github.com/drewnoakes" />
+// </summary>
+// --------------------------------------------------------------------------------------------------------------------
+
+namespace ImageProcessor.Imaging.Quantizers.WuQuantizer
 {
+    /// <summary>
+    /// Represents a cube cut.
+    /// Adapted from <see href="https://github.com/drewnoakes"/>
+    /// </summary>
     internal struct CubeCut
     {
+        /// <summary>
+        /// The position.
+        /// </summary>
         public readonly byte? Position;
+
+        /// <summary>
+        /// The value.
+        /// </summary>
         public readonly float Value;
 
+        /// <summary>
+        /// Initializes a new instance of the <see cref="CubeCut"/> struct.
+        /// </summary>
+        /// <param name="cutPoint">
+        /// The cut point.
+        /// </param>
+        /// <param name="result">
+        /// The result.
+        /// </param>
         public CubeCut(byte? cutPoint, float result)
         {
-            Position = cutPoint;
-            Value = result;
+            this.Position = cutPoint;
+            this.Value = result;
         }
     }
 }

src/ImageProcessor/Imaging/Quantizers/WuQuantizer/IWuQuantizer.cs

@@ -1,9 +1,40 @@
-using System.Drawing;
+// --------------------------------------------------------------------------------------------------------------------
+// <copyright file="IWuQuantizer.cs" company="James South">
+//   Copyright (c) James South.
+//   Licensed under the Apache License, Version 2.0.
+// </copyright>
+// <summary>
+//   The WuQuantizer interface.
+//   Adapted from <see href="https://github.com/drewnoakes" />
+// </summary>
+// --------------------------------------------------------------------------------------------------------------------
 
-namespace nQuant
+namespace ImageProcessor.Imaging.Quantizers.WuQuantizer
 {
+    using System.Drawing;
+
+    /// <summary>
+    /// The WuQuantizer interface.
+    /// Adapted from <see href="https://github.com/drewnoakes" />
+    /// </summary>
     public interface IWuQuantizer
     {
+        /// <summary>
+        /// Quantizes the given image.
+        /// </summary>
+        /// <param name="image">
+        /// The 32 bit per pixel <see cref="Image"/>.
+        /// </param>
+        /// <param name="alphaThreshold">
+        /// The alpha threshold. All colors with an alpha value less than this will be 
+        /// considered fully transparent
+        /// </param>
+        /// <param name="alphaFader">
+        /// The alpha fader. Alpha values will be normalized to the nearest multiple of this value.
+        /// </param>
+        /// <returns>
+        /// The quantized <see cref="Image"/>.
+        /// </returns>
         Image QuantizeImage(Bitmap image, int alphaThreshold, int alphaFader);
     }
 }

src/ImageProcessor/Imaging/Quantizers/WuQuantizer/ImageBuffer.cs

@@ -1,75 +1,106 @@
-using System;
-using System.Collections.Generic;
-using System.Drawing;
-using System.Drawing.Imaging;
-using System.Linq;
-using System.Runtime.InteropServices;
-using System.Text;
+// --------------------------------------------------------------------------------------------------------------------
+// <copyright file="ImageBuffer.cs" company="James South">
+//   Copyright (c) James South.
+//   Licensed under the Apache License, Version 2.0.
+// </copyright>
+// <summary>
+//   The image buffer for storing pixel information.
+//   Adapted from <see href="https://github.com/drewnoakes" />
+// </summary>
+// --------------------------------------------------------------------------------------------------------------------
 
-namespace nQuant
+namespace ImageProcessor.Imaging.Quantizers.WuQuantizer
 {
-    class ImageBuffer
+    using System.Collections.Generic;
+    using System.Drawing;
+    using System.Drawing.Imaging;
+    using System.Runtime.InteropServices;
+
+    /// <summary>
+    /// The image buffer for storing pixel information.
+    /// Adapted from <see href="https://github.com/drewnoakes"/>
+    /// </summary>
+    internal class ImageBuffer
     {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ImageBuffer"/> class.
+        /// </summary>
+        /// <param name="image">
+        /// The image to store.
+        /// </param>
         public ImageBuffer(Bitmap image)
         {
             this.Image = image;
         }
 
-        public Bitmap Image { get; set; }
-
-        protected const int Alpha = 3;
-        protected const int Red = 2;
-        protected const int Green = 1;
-        protected const int Blue = 0;
+        /// <summary>
+        /// Gets the image.
+        /// </summary>
+        public Bitmap Image { get; private set; }
 
-        public IEnumerable<Pixel> Pixels
+        /// <summary>
+        /// Gets the pixel lines.
+        /// </summary>
+        /// <exception cref="QuantizationException">
+        /// Thrown if the given image is not a 32 bit per pixel image.
+        /// </exception>
+        public IEnumerable<Pixel[]> PixelLines
         {
             get
             {
-                var bitDepth = System.Drawing.Image.GetPixelFormatSize(Image.PixelFormat);
+                int bitDepth = System.Drawing.Image.GetPixelFormatSize(this.Image.PixelFormat);
                 if (bitDepth != 32)
-                    throw new QuantizationException(string.Format("The image you are attempting to quantize does not contain a 32 bit ARGB palette. This image has a bit depth of {0} with {1} colors.", bitDepth, Image.Palette.Entries.Length));
+                {
+                    throw new QuantizationException(
+                        string.Format(
+                            "The image you are attempting to quantize does not contain a 32 bit ARGB palette. This image has a bit depth of {0} with {1} colors.",
+                            bitDepth,
+                            this.Image.Palette.Entries.Length));
+                }
 
                 int width = this.Image.Width;
                 int height = this.Image.Height;
                 int[] buffer = new int[width];
+                Pixel[] pixels = new Pixel[width];
                 for (int rowIndex = 0; rowIndex < height; rowIndex++)
                 {
                     BitmapData data = this.Image.LockBits(Rectangle.FromLTRB(0, rowIndex, width, rowIndex + 1), ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
                     try
                     {
                         Marshal.Copy(data.Scan0, buffer, 0, width);
-                        foreach (int pixel in buffer)
+                        for (int pixelIndex = 0; pixelIndex < buffer.Length; pixelIndex++)
                         {
-                            yield return new Pixel(pixel);
+                            pixels[pixelIndex] = new Pixel(buffer[pixelIndex]);
                         }
                     }
                     finally
                     {
                         this.Image.UnlockBits(data);
                     }
+
+                    yield return pixels;
                 }
             }
         }
 
-        public void UpdatePixelIndexes(IEnumerable<byte> indexes)
+        /// <summary>
+        /// Updates the pixel indexes.
+        /// </summary>
+        /// <param name="lineIndexes">
+        /// The line indexes.
+        /// </param>
+        public void UpdatePixelIndexes(IEnumerable<byte[]> lineIndexes)
         {
             int width = this.Image.Width;
             int height = this.Image.Height;
-            byte[] buffer = new byte[width];
-            IEnumerator<byte> indexesIterator = indexes.GetEnumerator();
+            var indexesIterator = lineIndexes.GetEnumerator();
             for (int rowIndex = 0; rowIndex < height; rowIndex++)
             {
-                for (int columnIndex = 0; columnIndex < buffer.Length; columnIndex++)
-                {
-                    indexesIterator.MoveNext();
-                    buffer[columnIndex] = indexesIterator.Current;
-                }
-
+                indexesIterator.MoveNext();
                 BitmapData data = this.Image.LockBits(Rectangle.FromLTRB(0, rowIndex, width, rowIndex + 1), ImageLockMode.WriteOnly, PixelFormat.Format8bppIndexed);
                 try
                 {
-                    Marshal.Copy(buffer, 0, data.Scan0, width);
+                    Marshal.Copy(indexesIterator.Current, 0, data.Scan0, width);
                 }
                 finally
                 {
@@ -78,4 +109,4 @@ namespace nQuant
             }
         }
     }
-}
+}

src/ImageProcessor/Imaging/Quantizers/WuQuantizer/Lookup.cs

@@ -1,10 +0,0 @@
-namespace nQuant
-{
-    public class Lookup
-    {
-        public int Alpha;
-        public int Red;
-        public int Green;
-        public int Blue;
-    }
-}

src/ImageProcessor/Imaging/Quantizers/WuQuantizer/PaletteBuffer.cs

@@ -1,52 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Drawing;
-using System.Drawing.Imaging;
-using System.Linq;
-using System.Text;
-
-namespace nQuant
-{
-    class PaletteBuffer
-    {
-        public PaletteBuffer(int colorCount)
-        {
-            Alphas = new int[colorCount + 1];
-            Reds = new int[colorCount + 1];
-            Greens = new int[colorCount + 1];
-            Blues = new int[colorCount + 1];
-            Sums = new int[colorCount + 1];
-        }
-
-        public ColorPalette BuildPalette(ColorPalette palette)
-        {
-            var alphas = this.Alphas;
-            var reds = this.Reds;
-            var greens = this.Greens;
-            var blues = this.Blues;
-            var sums = this.Sums;
-
-            for (var paletteIndex = 0; paletteIndex < Sums.Length; paletteIndex++)
-            {
-                if (sums[paletteIndex] > 0)
-                {
-                    alphas[paletteIndex] /= sums[paletteIndex];
-                    reds[paletteIndex] /= sums[paletteIndex];
-                    greens[paletteIndex] /= sums[paletteIndex];
-                    blues[paletteIndex] /= sums[paletteIndex];
-                }
-
-                var color = Color.FromArgb(alphas[paletteIndex], reds[paletteIndex], greens[paletteIndex], blues[paletteIndex]);
-                palette.Entries[paletteIndex] = color;
-            }
-
-            return palette;
-        }
-
-        public int[] Alphas { get; set; }
-        public int[] Reds { get; set; }
-        public int[] Greens { get; set; }
-        public int[] Blues { get; set; }
-        public int[] Sums { get; set; }
-    }
-}

src/ImageProcessor/Imaging/Quantizers/WuQuantizer/PaletteColorHistory.cs

@@ -0,0 +1,73 @@
+// --------------------------------------------------------------------------------------------------------------------
+// <copyright file="PaletteColorHistory.cs" company="James South">
+//   Copyright (c) James South.
+//   Licensed under the Apache License, Version 2.0.
+// </copyright>
+// <summary>
+//   The palette color history.
+//   Adapted from <see href="https://github.com/drewnoakes" />
+// </summary>
+// --------------------------------------------------------------------------------------------------------------------
+
+namespace ImageProcessor.Imaging.Quantizers.WuQuantizer
+{
+    using System.Drawing;
+
+    /// <summary>
+    /// The palette color history.
+    /// Adapted from <see href="https://github.com/drewnoakes" />
+    /// </summary>
+    internal struct PaletteColorHistory
+    {
+        /// <summary>
+        /// The alpha component.
+        /// </summary>
+        public int Alpha;
+
+        /// <summary>
+        /// The red component.
+        /// </summary>
+        public int Red;
+
+        /// <summary>
+        /// The green component.
+        /// </summary>
+        public int Green;
+
+        /// <summary>
+        /// The blue component.
+        /// </summary>
+        public int Blue;
+
+        /// <summary>
+        /// The sum of the color components.
+        /// </summary>
+        public int Sum;
+
+        /// <summary>
+        /// Normalizes the color.
+        /// </summary>
+        /// <returns>
+        /// The normalized <see cref="Color"/>.
+        /// </returns>
+        public Color ToNormalizedColor()
+        {
+            return (this.Sum != 0) ? Color.FromArgb(this.Alpha /= this.Sum, this.Red /= this.Sum, this.Green /= this.Sum, this.Blue /= this.Sum) : Color.Empty;
+        }
+
+        /// <summary>
+        /// Adds a pixel to the color history.
+        /// </summary>
+        /// <param name="pixel">
+        /// The pixel.
+        /// </param>
+        public void AddPixel(Pixel pixel)
+        {
+            this.Alpha += pixel.Alpha;
+            this.Red += pixel.Red;
+            this.Green += pixel.Green;
+            this.Blue += pixel.Blue;
+            this.Sum++;
+        }
+    }
+}

src/ImageProcessor/Imaging/Quantizers/WuQuantizer/PaletteLookup.cs

@@ -1,46 +1,43 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-
-namespace nQuant
+namespace ImageProcessor.Imaging.Quantizers.WuQuantizer
 {
+    using System;
+    using System.Collections.Generic;
+    using System.Linq;
+
     class PaletteLookup
     {
         private int mMask;
-        private Dictionary<int, List<LookupNode>> mLookup = new Dictionary<int, List<LookupNode>>(255);
-        private List<LookupNode> Palette { get; set; }
+        private Dictionary<int, LookupNode[]> mLookup;
+        private LookupNode[] Palette { get; set; }
 
-        public PaletteLookup(List<Pixel> palette)
+        public PaletteLookup(Pixel[] palette)
         {
-            Palette = new List<LookupNode>(palette.Count);
-            for (int paletteIndex = 0; paletteIndex < palette.Count; paletteIndex++)
+            Palette = new LookupNode[palette.Length];
+            for (int paletteIndex = 0; paletteIndex < palette.Length; paletteIndex++)
             {
-                Palette.Add(new LookupNode { Pixel = palette[paletteIndex], PaletteIndex = (byte)paletteIndex });
+                Palette[paletteIndex] = new LookupNode { Pixel = palette[paletteIndex], PaletteIndex = (byte)paletteIndex };
             }
             BuildLookup(palette);
         }
 
         public byte GetPaletteIndex(Pixel pixel)
         {
-
             int pixelKey = pixel.Argb & mMask;
-            List<LookupNode> bucket;
+            LookupNode[] bucket;
             if (!mLookup.TryGetValue(pixelKey, out bucket))
             {
                 bucket = Palette;
             }
 
-            if (bucket.Count == 1)
+            if (bucket.Length == 1)
             {
                 return bucket[0].PaletteIndex;
             }
 
             int bestDistance = int.MaxValue;
             byte bestMatch = 0;
-            for (int lookupIndex = 0; lookupIndex < bucket.Count; lookupIndex++)
+            foreach (var lookup in bucket)
             {
-                var lookup = bucket[lookupIndex];
                 var lookupPixel = lookup.Pixel;
 
                 var deltaAlpha = pixel.Alpha - lookupPixel.Alpha;
@@ -61,29 +58,41 @@ namespace nQuant
                 bestDistance = distance;
                 bestMatch = lookup.PaletteIndex;
             }
+
+            if ((bucket == Palette) && (pixelKey != 0))
+            {
+                mLookup[pixelKey] = new LookupNode[] { bucket[bestMatch] };
+            }
+
             return bestMatch;
         }
 
-        private void BuildLookup(List<Pixel> palette)
+        private void BuildLookup(Pixel[] palette)
         {
             int mask = GetMask(palette);
+            Dictionary<int, List<LookupNode>> tempLookup = new Dictionary<int, List<LookupNode>>();
             foreach (LookupNode lookup in Palette)
             {
                 int pixelKey = lookup.Pixel.Argb & mask;
 
                 List<LookupNode> bucket;
-                if (!mLookup.TryGetValue(pixelKey, out bucket))
+                if (!tempLookup.TryGetValue(pixelKey, out bucket))
                 {
                     bucket = new List<LookupNode>();
-                    mLookup[pixelKey] = bucket;
+                    tempLookup[pixelKey] = bucket;
                 }
                 bucket.Add(lookup);
             }
 
+            mLookup = new Dictionary<int, LookupNode[]>(tempLookup.Count);
+            foreach (var key in tempLookup.Keys)
+            {
+                mLookup[key] = tempLookup[key].ToArray();
+            }
             mMask = mask;
         }
 
-        private static int GetMask(List<Pixel> palette)
+        private static int GetMask(Pixel[] palette)
         {
             IEnumerable<byte> alphas = from pixel in palette
                                        select pixel.Alpha;
@@ -107,12 +116,12 @@ namespace nQuant
 
             double totalUniques = uniqueAlphas + uniqueReds + uniqueGreens + uniqueBlues;
 
-            const double AvailableBits = 8f;
+            double AvailableBits = 1.0 + Math.Log(uniqueAlphas * uniqueReds * uniqueGreens * uniqueBlues);
 
             byte alphaMask = ComputeBitMask(maxAlpha, Convert.ToInt32(Math.Round(uniqueAlphas / totalUniques * AvailableBits)));
             byte redMask = ComputeBitMask(maxRed, Convert.ToInt32(Math.Round(uniqueReds / totalUniques * AvailableBits)));
             byte greenMask = ComputeBitMask(maxGreen, Convert.ToInt32(Math.Round(uniqueGreens / totalUniques * AvailableBits)));
-            byte blueMask = ComputeBitMask(maxAlpha, Convert.ToInt32(Math.Round(uniqueBlues / totalUniques * AvailableBits)));
+            byte blueMask = ComputeBitMask(maxBlue, Convert.ToInt32(Math.Round(uniqueBlues / totalUniques * AvailableBits)));
 
             Pixel maskedPixel = new Pixel(alphaMask, redMask, greenMask, blueMask);
             return maskedPixel.Argb;

src/ImageProcessor/Imaging/Quantizers/WuQuantizer/Pixel.cs

@@ -1,7 +1,7 @@
-namespace nQuant
+using System.Diagnostics;
+using System.Runtime.InteropServices;
+namespace ImageProcessor.Imaging.Quantizers.WuQuantizer
 {
-    using System.Runtime.InteropServices;
-
     [StructLayout(LayoutKind.Explicit)]
     public struct Pixel
     {
@@ -12,32 +12,27 @@ namespace nQuant
             Red = red;
             Green = green;
             Blue = blue;
+
+            Debug.Assert(Argb == (alpha << 24 | red << 16 | green << 8 | blue));
         }
 
-        /// <summary>
-        /// Initializes a new instance of the <see cref="Pixel"/> struct.
-        /// </summary>
-        /// <param name="argb">
-        /// The combined color components.
-        /// </param>
         public Pixel(int argb)
             : this()
         {
-            this.Argb = argb;
-        }
-
-        public long Amplitude()
-        {
-            return (Alpha * Alpha) + (Red * Red) + (Green * Green) + (Blue * Blue);
+            Argb = argb;
+            Debug.Assert(Alpha == ((uint)argb >> 24));
+            Debug.Assert(Red == ((uint)(argb >> 16) & 255));
+            Debug.Assert(Green == ((uint)(argb >> 8) & 255));
+            Debug.Assert(Blue == ((uint)argb & 255));
         }
 
-        [FieldOffsetAttribute(3)]
+        [FieldOffset(3)]
         public byte Alpha;
-        [FieldOffsetAttribute(2)]
+        [FieldOffset(2)]
         public byte Red;
-        [FieldOffsetAttribute(1)]
+        [FieldOffset(1)]
         public byte Green;
-        [FieldOffsetAttribute(0)]
+        [FieldOffset(0)]
         public byte Blue;
         [FieldOffset(0)]
         public int Argb;

src/ImageProcessor/Imaging/Quantizers/WuQuantizer/QuantizationException.cs

@@ -3,8 +3,9 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 
-namespace nQuant
+namespace ImageProcessor.Imaging.Quantizers.WuQuantizer
 {
+    [Serializable]
     public class QuantizationException : ApplicationException
     {
         public QuantizationException(string message) : base(message)

src/ImageProcessor/Imaging/Quantizers/WuQuantizer/WuQuantizer.cs

@@ -1,52 +1,49 @@
-using System;
-using System.Collections.Generic;
+using System.Collections.Generic;
 using System.Drawing;
+using System.Drawing.Imaging;
 
-namespace nQuant
+namespace ImageProcessor.Imaging.Quantizers.WuQuantizer
 {
-    using System.Drawing.Imaging;
-
     public class WuQuantizer : WuQuantizerBase, IWuQuantizer
     {
-        private IEnumerable<byte> indexedPixels(ImageBuffer image, List<Pixel> lookups, int alphaThreshold, PaletteBuffer paletteBuffer)
+        private static IEnumerable<byte[]> IndexedPixels(ImageBuffer image, Pixel[] lookups, int alphaThreshold, PaletteColorHistory[] paletteHistogram)
         {
-            var alphas = paletteBuffer.Alphas;
-            var reds = paletteBuffer.Reds;
-            var greens = paletteBuffer.Greens;
-            var blues = paletteBuffer.Blues;
-            var sums = paletteBuffer.Sums;
-
-            PaletteLookup lookup = new PaletteLookup(lookups);
-
-            foreach (Pixel pixel in image.Pixels)
+            var lineIndexes = new byte[image.Image.Width];
+            var lookup = new PaletteLookup(lookups);
+            foreach (var pixelLine in image.PixelLines)
             {
-                byte bestMatch = 255;
-
-                if (pixel.Alpha >= alphaThreshold)
+                for (int pixelIndex = 0; pixelIndex < pixelLine.Length; pixelIndex++)
                 {
-                    bestMatch = lookup.GetPaletteIndex(pixel);
-
-                    alphas[bestMatch] += pixel.Alpha;
-                    reds[bestMatch] += pixel.Red;
-                    greens[bestMatch] += pixel.Green;
-                    blues[bestMatch] += pixel.Blue;
-                    sums[bestMatch]++;
+                    Pixel pixel = pixelLine[pixelIndex];
+                    byte bestMatch = AlphaColor;
+                    if (pixel.Alpha >= alphaThreshold)
+                    {
+                        bestMatch = lookup.GetPaletteIndex(pixel);
+                        paletteHistogram[bestMatch].AddPixel(pixel);
+                    }
+                    lineIndexes[pixelIndex] = bestMatch;
                 }
-
-                yield return bestMatch;
+                yield return lineIndexes;
             }
         }
 
-
-        internal override Image GetQuantizedImage(ImageBuffer image, int colorCount, List<Pixel> lookups, int alphaThreshold)
+        internal override Image GetQuantizedImage(ImageBuffer image, int colorCount, Pixel[] lookups, int alphaThreshold)
         {
             var result = new Bitmap(image.Image.Width, image.Image.Height, PixelFormat.Format8bppIndexed);
-            result.SetResolution(image.Image.HorizontalResolution, image.Image.VerticalResolution);
             var resultBuffer = new ImageBuffer(result);
-            PaletteBuffer paletteBuffer = new PaletteBuffer(colorCount);
-            resultBuffer.UpdatePixelIndexes(indexedPixels(image, lookups, alphaThreshold, paletteBuffer));
-            result.Palette = paletteBuffer.BuildPalette(result.Palette);
+            var paletteHistogram = new PaletteColorHistory[colorCount + 1];
+            resultBuffer.UpdatePixelIndexes(IndexedPixels(image, lookups, alphaThreshold, paletteHistogram));
+            result.Palette = BuildPalette(result.Palette, paletteHistogram);
             return result;
         }
+
+        private static ColorPalette BuildPalette(ColorPalette palette, PaletteColorHistory[] paletteHistogram)
+        {
+            for (int paletteColorIndex = 0; paletteColorIndex < paletteHistogram.Length; paletteColorIndex++)
+            {
+                palette.Entries[paletteColorIndex] = paletteHistogram[paletteColorIndex].ToNormalizedColor();
+            }
+            return palette;
+        }
     }
 }

src/ImageProcessor/Imaging/Quantizers/WuQuantizer/WuQuantizerBase.cs

@@ -1,15 +1,28 @@
 using System;
-using System.Collections.Generic;
 using System.Drawing;
-using System.Drawing.Imaging;
 using System.Linq;
-using System.Runtime.InteropServices;
 
-namespace nQuant
+namespace ImageProcessor.Imaging.Quantizers.WuQuantizer
 {
+    public class Histogram
+    {
+        private const int SideSize = 33;
+        internal readonly ColorMoment[, , ,] Moments;
+
+        public Histogram()
+        {
+            // 47,436,840 bytes
+            Moments = new ColorMoment[SideSize, SideSize, SideSize, SideSize];
+        }
+
+        internal void Clear()
+        {
+            Array.Clear(Moments, 0, SideSize*SideSize*SideSize*SideSize);
+        }
+    }
+
     public abstract class WuQuantizerBase
     {
-        private const int MaxColor = 256;
         protected const byte AlphaColor = 255;
         protected const int Alpha = 3;
         protected const int Red = 2;
@@ -25,66 +38,82 @@ namespace nQuant
 
         public Image QuantizeImage(Bitmap image, int alphaThreshold, int alphaFader)
         {
-            var colorCount = MaxColor;
-            ImageBuffer buffer = new ImageBuffer(image);
-            var data = BuildHistogram(buffer, alphaThreshold, alphaFader);
-
-            data = CalculateMoments(data);
-            var cubes = SplitData(ref colorCount, data);
-            var lookups = BuildLookups(cubes, data);
-            return GetQuantizedImage(buffer, colorCount, lookups, alphaThreshold);
+            return QuantizeImage(image, alphaThreshold, alphaFader, null, 256);
+        }
+
+        public Image QuantizeImage(Bitmap image, int alphaThreshold, int alphaFader, Histogram histogram, int maxColors)
+        {
+            var buffer = new ImageBuffer(image);
+
+            if (histogram == null)
+                histogram = new Histogram();
+            else
+                histogram.Clear();
+
+            BuildHistogram(histogram, buffer, alphaThreshold, alphaFader);
+            CalculateMoments(histogram.Moments);
+            var cubes = SplitData(ref maxColors, histogram.Moments);
+            var lookups = BuildLookups(cubes, histogram.Moments);
+            return GetQuantizedImage(buffer, maxColors, lookups, alphaThreshold);
         }
 
-        private static ColorData BuildHistogram(ImageBuffer sourceImage, int alphaThreshold, int alphaFader)
+        private static void BuildHistogram(Histogram histogram, ImageBuffer sourceImage, int alphaThreshold, int alphaFader)
         {
-            ColorData colorData = new ColorData(MaxSideIndex);
-            foreach (Pixel pixel in sourceImage.Pixels)
+            var moments = histogram.Moments;
+
+            foreach(var pixelLine in sourceImage.PixelLines)
             {
-                if (pixel.Alpha >= alphaThreshold)
+                for (int pixelIndex = 0; pixelIndex < pixelLine.Length; pixelIndex++)
                 {
-                    Pixel indexedPixel = pixel;
-                    if (indexedPixel.Alpha < 255)
+                    Pixel pixel = pixelLine[pixelIndex];
+                    byte pixelAlpha = pixel.Alpha;
+                    if (pixelAlpha >= alphaThreshold)
                     {
-                        int alpha = pixel.Alpha + (pixel.Alpha % alphaFader);
-                        indexedPixel.Alpha = (byte)(alpha > 255 ? 255 : alpha);
-                    }
+                        if (pixelAlpha < 255)
+                        {
+                            var alpha = pixel.Alpha + (pixel.Alpha % alphaFader);
+                            pixelAlpha = (byte)(alpha > 255 ? 255 : alpha);
+                        }
 
-                    indexedPixel.Alpha = (byte)((indexedPixel.Alpha >> 3) + 1);
-                    indexedPixel.Red = (byte)((indexedPixel.Red >> 3) + 1);
-                    indexedPixel.Green = (byte)((indexedPixel.Green >> 3) + 1);
-                    indexedPixel.Blue = (byte)((indexedPixel.Blue >> 3) + 1);
-                    colorData.Moments[indexedPixel.Alpha, indexedPixel.Red, indexedPixel.Green, indexedPixel.Blue].Add(pixel);
+                        byte pixelRed = pixel.Red;
+                        byte pixelGreen = pixel.Green;
+                        byte pixelBlue = pixel.Blue;
+
+                        pixelAlpha = (byte)((pixelAlpha >> 3) + 1);
+                        pixelRed = (byte)((pixelRed >> 3) + 1);
+                        pixelGreen = (byte)((pixelGreen >> 3) + 1);
+                        pixelBlue = (byte)((pixelBlue >> 3) + 1);
+                        moments[pixelAlpha, pixelRed, pixelGreen, pixelBlue].Add(pixel);
+                    }
                 }
             }
-
-            return colorData;
         }
 
-        private static ColorData CalculateMoments(ColorData data)
+        private static void CalculateMoments(ColorMoment[, , ,] moments)
         {
             var xarea = new ColorMoment[SideSize, SideSize];
             var area = new ColorMoment[SideSize];
-            var moments = data.Moments;
-
-            for (var alphaIndex = 1; alphaIndex <= MaxSideIndex; ++alphaIndex)
+            for (var alphaIndex = 1; alphaIndex < SideSize; alphaIndex++)
             {
-                for (var redIndex = 1; redIndex <= MaxSideIndex; ++redIndex)
+                for (var redIndex = 1; redIndex < SideSize; redIndex++)
                 {
                     Array.Clear(area, 0, area.Length);
-                    for (var greenIndex = 1; greenIndex <= MaxSideIndex; ++greenIndex)
+                    for (var greenIndex = 1; greenIndex < SideSize; greenIndex++)
                     {
-                        ColorMoment line = new ColorMoment();
-                        for (var blueIndex = 1; blueIndex <= MaxSideIndex; ++blueIndex)
+                        var line = new ColorMoment();
+                        for (var blueIndex = 1; blueIndex < SideSize; blueIndex++)
                         {
                             line.AddFast(ref moments[alphaIndex, redIndex, greenIndex, blueIndex]);
                             area[blueIndex].AddFast(ref line);
                             xarea[greenIndex, blueIndex].AddFast(ref area[blueIndex]);
-                            moments[alphaIndex, redIndex, greenIndex, blueIndex] = moments[alphaIndex - 1, redIndex, greenIndex, blueIndex] + xarea[greenIndex, blueIndex];
+
+                            ColorMoment moment = moments[alphaIndex - 1, redIndex, greenIndex, blueIndex];
+                            moment.AddFast(ref xarea[greenIndex, blueIndex]);
+                            moments[alphaIndex, redIndex, greenIndex, blueIndex] = moment;
                         }
                     }
                 }
             }
-            return data;
         }
 
         private static ColorMoment Top(Box cube, int direction, int position, ColorMoment[, , ,] moment)
@@ -185,21 +214,19 @@ namespace nQuant
             }
         }
 
-        private static CubeCut Maximize(ColorData data, Box cube, int direction, byte first, byte last, ColorMoment whole)
+        private static CubeCut Maximize(ColorMoment[, , ,] moments, Box cube, int direction, byte first, byte last, ColorMoment whole)
         {
-            var bottom = Bottom(cube, direction, data.Moments);
-            float result = 0.0f;
+            var bottom = Bottom(cube, direction, moments);
+            var result = 0.0f;
             byte? cutPoint = null;
 
-            for (byte position = first; position < last; ++position)
+            for (var position = first; position < last; ++position)
             {
-                var half = bottom + Top(cube, direction, position, data.Moments);
-                if (half.Weight == 0)
-                {
-                    continue;
-                }
+                var half = bottom + Top(cube, direction, position, moments);
+                if (half.Weight == 0) continue;
+
+                var temp = half.WeightedDistance();
 
-                long temp = half.WeightedDistance();
                 half = whole - half;
                 if (half.Weight != 0)
                 {
@@ -216,14 +243,14 @@ namespace nQuant
             return new CubeCut(cutPoint, result);
         }
 
-        private bool Cut(ColorData data, ref Box first, ref Box second)
+        private static bool Cut(ColorMoment[, , ,] moments, ref Box first, ref Box second)
         {
             int direction;
-            var whole = Volume(first, data.Moments);
-            var maxAlpha = Maximize(data, first, Alpha, (byte)(first.AlphaMinimum + 1), first.AlphaMaximum, whole);
-            var maxRed = Maximize(data, first, Red, (byte)(first.RedMinimum + 1), first.RedMaximum, whole);
-            var maxGreen = Maximize(data, first, Green, (byte)(first.GreenMinimum + 1), first.GreenMaximum, whole);
-            var maxBlue = Maximize(data, first, Blue, (byte)(first.BlueMinimum + 1), first.BlueMaximum, whole);
+            var whole = Volume(first, moments);
+            var maxAlpha = Maximize(moments, first, Alpha, (byte)(first.AlphaMinimum + 1), first.AlphaMaximum, whole);
+            var maxRed = Maximize(moments, first, Red, (byte)(first.RedMinimum + 1), first.RedMaximum, whole);
+            var maxGreen = Maximize(moments, first, Green, (byte)(first.GreenMinimum + 1), first.GreenMaximum, whole);
+            var maxBlue = Maximize(moments, first, Blue, (byte)(first.BlueMinimum + 1), first.BlueMaximum, whole);
 
             if ((maxAlpha.Value >= maxRed.Value) && (maxAlpha.Value >= maxGreen.Value) && (maxAlpha.Value >= maxBlue.Value))
             {
@@ -248,28 +275,28 @@ namespace nQuant
             switch (direction)
             {
                 case Alpha:
-                    second.AlphaMinimum = first.AlphaMaximum = (byte)maxAlpha.Position;
+                    second.AlphaMinimum = first.AlphaMaximum = (byte) maxAlpha.Position;
                     second.RedMinimum = first.RedMinimum;
                     second.GreenMinimum = first.GreenMinimum;
                     second.BlueMinimum = first.BlueMinimum;
                     break;
 
                 case Red:
-                    second.RedMinimum = first.RedMaximum = (byte)maxRed.Position;
+                    second.RedMinimum = first.RedMaximum = (byte) maxRed.Position;
                     second.AlphaMinimum = first.AlphaMinimum;
                     second.GreenMinimum = first.GreenMinimum;
                     second.BlueMinimum = first.BlueMinimum;
                     break;
 
                 case Green:
-                    second.GreenMinimum = first.GreenMaximum = (byte)maxGreen.Position;
+                    second.GreenMinimum = first.GreenMaximum = (byte) maxGreen.Position;
                     second.AlphaMinimum = first.AlphaMinimum;
                     second.RedMinimum = first.RedMinimum;
                     second.BlueMinimum = first.BlueMinimum;
                     break;
 
                 case Blue:
-                    second.BlueMinimum = first.BlueMaximum = (byte)maxBlue.Position;
+                    second.BlueMinimum = first.BlueMaximum = (byte) maxBlue.Position;
                     second.AlphaMinimum = first.AlphaMinimum;
                     second.RedMinimum = first.RedMinimum;
                     second.GreenMinimum = first.GreenMinimum;
@@ -282,9 +309,9 @@ namespace nQuant
             return true;
         }
 
-        private static float CalculateVariance(ColorData data, Box cube)
+        private static float CalculateVariance(ColorMoment[, , ,] moments, Box cube)
         {
-            ColorMoment volume = Volume(cube, data.Moments);
+            ColorMoment volume = Volume(cube, moments);
             return volume.Variance();
         }
 
@@ -309,43 +336,22 @@ namespace nQuant
                     moment[cube.AlphaMinimum, cube.RedMinimum, cube.GreenMinimum, cube.BlueMinimum]);
         }
 
-        private static float VolumeFloat(Box cube, float[, , ,] moment)
-        {
-            return (moment[cube.AlphaMaximum, cube.RedMaximum, cube.GreenMaximum, cube.BlueMaximum] -
-                    moment[cube.AlphaMaximum, cube.RedMaximum, cube.GreenMinimum, cube.BlueMaximum] -
-                    moment[cube.AlphaMaximum, cube.RedMinimum, cube.GreenMaximum, cube.BlueMaximum] +
-                    moment[cube.AlphaMaximum, cube.RedMinimum, cube.GreenMinimum, cube.BlueMaximum] -
-                    moment[cube.AlphaMinimum, cube.RedMaximum, cube.GreenMaximum, cube.BlueMaximum] +
-                    moment[cube.AlphaMinimum, cube.RedMaximum, cube.GreenMinimum, cube.BlueMaximum] +
-                    moment[cube.AlphaMinimum, cube.RedMinimum, cube.GreenMaximum, cube.BlueMaximum] -
-                    moment[cube.AlphaMinimum, cube.RedMinimum, cube.GreenMinimum, cube.BlueMaximum]) -
-
-                   (moment[cube.AlphaMaximum, cube.RedMaximum, cube.GreenMaximum, cube.BlueMinimum] -
-                    moment[cube.AlphaMinimum, cube.RedMaximum, cube.GreenMaximum, cube.BlueMinimum] -
-                    moment[cube.AlphaMaximum, cube.RedMaximum, cube.GreenMinimum, cube.BlueMinimum] +
-                    moment[cube.AlphaMinimum, cube.RedMaximum, cube.GreenMinimum, cube.BlueMinimum] -
-                    moment[cube.AlphaMaximum, cube.RedMinimum, cube.GreenMaximum, cube.BlueMinimum] +
-                    moment[cube.AlphaMinimum, cube.RedMinimum, cube.GreenMaximum, cube.BlueMinimum] +
-                    moment[cube.AlphaMaximum, cube.RedMinimum, cube.GreenMinimum, cube.BlueMinimum] -
-                    moment[cube.AlphaMinimum, cube.RedMinimum, cube.GreenMinimum, cube.BlueMinimum]);
-        }
-
-        private Box[] SplitData(ref int colorCount, ColorData data)
+        private static Box[] SplitData(ref int colorCount, ColorMoment[, , ,] moments)
         {
             --colorCount;
             var next = 0;
-            var volumeVariance = new float[MaxColor];
-            var cubes = new Box[MaxColor];
+            var volumeVariance = new float[colorCount];
+            var cubes = new Box[colorCount];
             cubes[0].AlphaMaximum = MaxSideIndex;
             cubes[0].RedMaximum = MaxSideIndex;
             cubes[0].GreenMaximum = MaxSideIndex;
             cubes[0].BlueMaximum = MaxSideIndex;
             for (var cubeIndex = 1; cubeIndex < colorCount; ++cubeIndex)
             {
-                if (Cut(data, ref cubes[next], ref cubes[cubeIndex]))
+                if (Cut(moments, ref cubes[next], ref cubes[cubeIndex]))
                 {
-                    volumeVariance[next] = cubes[next].Size > 1 ? CalculateVariance(data, cubes[next]) : 0.0f;
-                    volumeVariance[cubeIndex] = cubes[cubeIndex].Size > 1 ? CalculateVariance(data, cubes[cubeIndex]) : 0.0f;
+                    volumeVariance[next] = cubes[next].Size > 1 ? CalculateVariance(moments, cubes[next]) : 0.0f;
+                    volumeVariance[cubeIndex] = cubes[cubeIndex].Size > 1 ? CalculateVariance(moments, cubes[cubeIndex]) : 0.0f;
                 }
                 else
                 {
@@ -370,18 +376,15 @@ namespace nQuant
             return cubes.Take(colorCount).ToArray();
         }
 
-        private List<Pixel> BuildLookups(Box[] cubes, ColorData data)
+        private static Pixel[] BuildLookups(Box[] cubes, ColorMoment[, , ,] moments)
         {
-            List<Pixel> lookups = new List<Pixel>(cubes.Length);
+            Pixel[] lookups = new Pixel[cubes.Length];
 
-            foreach (var cube in cubes)
+            for (int cubeIndex = 0; cubeIndex < cubes.Length; cubeIndex++)
             {
-                var volume = Volume(cube, data.Moments);
+                var volume = Volume(cubes[cubeIndex], moments);
 
-                if (volume.Weight <= 0)
-                {
-                    continue;
-                }
+                if (volume.Weight <= 0) continue;
 
                 var lookup = new Pixel
                     {
@@ -390,13 +393,11 @@ namespace nQuant
                         Green = (byte)(volume.Green / volume.Weight),
                         Blue = (byte)(volume.Blue / volume.Weight)
                     };
-
-                lookups.Add(lookup);
+                lookups[cubeIndex] = lookup;
             }
-
             return lookups;
         }
 
-        internal abstract Image GetQuantizedImage(ImageBuffer image, int colorCount, List<Pixel> lookups, int alphaThreshold);
+        internal abstract Image GetQuantizedImage(ImageBuffer image, int colorCount, Pixel[] lookups, int alphaThreshold);
     }
 }