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Former-commit-id: 239861ab1b9a51d4419b9792065dde13889df62e Former-commit-id: 11b9dc42a746382821c2cfa71101bee6ad795e15 Former-commit-id: f48eecab005836aa70c6ac3b3018d813ee5bba09af/merge-core
James Jackson-South
10 years ago
10 changed files with 916 additions and 60 deletions
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// <copyright file="Box.cs" company="James Jackson-South">
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// Copyright (c) James Jackson-South and contributors.
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// Licensed under the Apache License, Version 2.0.
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// </copyright>
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namespace ImageProcessorCore.Quantizers |
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{ |
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/// <summary>
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/// Represents a box color cube.
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/// </summary>
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internal sealed class Box |
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{ |
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/// <summary>
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/// Gets or sets the min red value, exclusive.
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/// </summary>
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public int R0 { get; set; } |
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/// <summary>
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/// Gets or sets the max red value, inclusive.
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/// </summary>
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public int R1 { get; set; } |
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/// <summary>
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/// Gets or sets the min green value, exclusive.
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/// </summary>
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public int G0 { get; set; } |
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/// <summary>
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/// Gets or sets the max green value, inclusive.
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/// </summary>
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public int G1 { get; set; } |
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/// <summary>
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/// Gets or sets the min blue value, exclusive.
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/// </summary>
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public int B0 { get; set; } |
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/// <summary>
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/// Gets or sets the max blue value, inclusive.
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/// </summary>
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public int B1 { get; set; } |
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/// <summary>
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/// Gets or sets the min alpha value, exclusive.
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/// </summary>
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public int A0 { get; set; } |
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/// <summary>
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/// Gets or sets the max alpha value, inclusive.
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/// </summary>
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public int A1 { get; set; } |
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/// <summary>
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/// Gets or sets the volume.
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/// </summary>
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public int Volume { get; set; } |
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} |
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} |
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// <copyright file="WuQuantizer.cs" company="James Jackson-South">
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// Copyright (c) James Jackson-South and contributors.
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// Licensed under the Apache License, Version 2.0.
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// </copyright>
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namespace ImageProcessorCore.Quantizers |
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{ |
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using System; |
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using System.Collections.Generic; |
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/// <summary>
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/// An implementation of Wu's color quantizer with alpha channel.
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/// </summary>
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/// <remarks>
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/// <para>
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/// Based on C Implementation of Xiaolin Wu's Color Quantizer (v. 2)
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/// (see Graphics Gems volume II, pages 126-133)
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/// (<see href="http://www.ece.mcmaster.ca/~xwu/cq.c"/>).
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/// </para>
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/// <para>
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/// This adaptation is based on the excellent JeremyAnsel.ColorQuant by Jérémy Ansel
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/// <see href="https://github.com/JeremyAnsel/JeremyAnsel.ColorQuant"/>
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/// </para>
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/// <para>
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/// Algorithm: Greedy orthogonal bipartition of RGB space for variance
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/// minimization aided by inclusion-exclusion tricks.
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/// For speed no nearest neighbor search is done. Slightly
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/// better performance can be expected by more sophisticated
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/// but more expensive versions.
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/// </para>
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/// </remarks>
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public sealed class WuQuantizer : IQuantizer |
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{ |
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/// <summary>
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/// The epsilon for comparing floating point numbers.
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/// </summary>
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private const float Epsilon = 0.001f; |
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/// <summary>
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/// The index bits.
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/// </summary>
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private const int IndexBits = 6; |
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/// <summary>
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/// The index alpha bits.
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/// </summary>
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private const int IndexAlphaBits = 3; |
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/// <summary>
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/// The index count.
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/// </summary>
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private const int IndexCount = (1 << IndexBits) + 1; |
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/// <summary>
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/// The index alpha count.
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/// </summary>
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private const int IndexAlphaCount = (1 << IndexAlphaBits) + 1; |
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/// <summary>
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/// The table length.
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/// </summary>
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private const int TableLength = IndexCount * IndexCount * IndexCount * IndexAlphaCount; |
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/// <summary>
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/// Moment of <c>P(c)</c>.
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/// </summary>
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private readonly long[] vwt; |
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/// <summary>
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/// Moment of <c>r*P(c)</c>.
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/// </summary>
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private readonly long[] vmr; |
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/// <summary>
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/// Moment of <c>g*P(c)</c>.
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/// </summary>
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private readonly long[] vmg; |
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/// <summary>
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/// Moment of <c>b*P(c)</c>.
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/// </summary>
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private readonly long[] vmb; |
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/// <summary>
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/// Moment of <c>a*P(c)</c>.
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/// </summary>
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private readonly long[] vma; |
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/// <summary>
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/// Moment of <c>c^2*P(c)</c>.
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/// </summary>
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private readonly double[] m2; |
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/// <summary>
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/// Color space tag.
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/// </summary>
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private readonly byte[] tag; |
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/// <summary>
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/// Initializes a new instance of the <see cref="WuQuantizer"/> class.
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/// </summary>
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public WuQuantizer() |
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{ |
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this.vwt = new long[TableLength]; |
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this.vmr = new long[TableLength]; |
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this.vmg = new long[TableLength]; |
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this.vmb = new long[TableLength]; |
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this.vma = new long[TableLength]; |
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this.m2 = new double[TableLength]; |
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this.tag = new byte[TableLength]; |
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} |
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/// <inheritdoc/>
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public QuantizedImage Quantize(ImageBase image, int maxColors) |
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{ |
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Guard.NotNull(image, nameof(image)); |
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int colorCount = maxColors.Clamp(1, 256); |
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this.Clear(); |
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this.Build3DHistogram(image); |
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this.Get3DMoments(); |
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Box[] cube; |
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this.BuildCube(out cube, ref colorCount); |
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return this.GenerateResult(image, colorCount, cube); |
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} |
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/// <summary>
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/// Gets an index.
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/// </summary>
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/// <param name="r">The red value.</param>
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/// <param name="g">The green value.</param>
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/// <param name="b">The blue value.</param>
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/// <param name="a">The alpha value.</param>
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/// <returns>The index.</returns>
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private static int GetPalleteIndex(int r, int g, int b, int a) |
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{ |
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return (r << ((IndexBits * 2) + IndexAlphaBits)) |
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+ (r << (IndexBits + IndexAlphaBits + 1)) |
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+ (g << (IndexBits + IndexAlphaBits)) |
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+ (r << (IndexBits * 2)) |
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+ (r << (IndexBits + 1)) |
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+ (g << IndexBits) |
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+ ((r + g + b) << IndexAlphaBits) |
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+ r + g + b + a; |
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} |
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/// <summary>
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/// Computes sum over a box of any given statistic.
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/// </summary>
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/// <param name="cube">The cube.</param>
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/// <param name="moment">The moment.</param>
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/// <returns>The result.</returns>
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private static double Volume(Box cube, long[] moment) |
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{ |
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return moment[GetPalleteIndex(cube.R1, cube.G1, cube.B1, cube.A1)] |
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- moment[GetPalleteIndex(cube.R1, cube.G1, cube.B1, cube.A0)] |
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- moment[GetPalleteIndex(cube.R1, cube.G1, cube.B0, cube.A1)] |
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+ moment[GetPalleteIndex(cube.R1, cube.G1, cube.B0, cube.A0)] |
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- moment[GetPalleteIndex(cube.R1, cube.G0, cube.B1, cube.A1)] |
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+ moment[GetPalleteIndex(cube.R1, cube.G0, cube.B1, cube.A0)] |
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+ moment[GetPalleteIndex(cube.R1, cube.G0, cube.B0, cube.A1)] |
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- moment[GetPalleteIndex(cube.R1, cube.G0, cube.B0, cube.A0)] |
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- moment[GetPalleteIndex(cube.R0, cube.G1, cube.B1, cube.A1)] |
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+ moment[GetPalleteIndex(cube.R0, cube.G1, cube.B1, cube.A0)] |
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+ moment[GetPalleteIndex(cube.R0, cube.G1, cube.B0, cube.A1)] |
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- moment[GetPalleteIndex(cube.R0, cube.G1, cube.B0, cube.A0)] |
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+ moment[GetPalleteIndex(cube.R0, cube.G0, cube.B1, cube.A1)] |
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- moment[GetPalleteIndex(cube.R0, cube.G0, cube.B1, cube.A0)] |
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- moment[GetPalleteIndex(cube.R0, cube.G0, cube.B0, cube.A1)] |
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+ moment[GetPalleteIndex(cube.R0, cube.G0, cube.B0, cube.A0)]; |
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} |
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/// <summary>
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/// Computes part of Volume(cube, moment) that doesn't depend on r1, g1, or b1 (depending on direction).
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/// </summary>
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/// <param name="cube">The cube.</param>
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/// <param name="direction">The direction.</param>
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/// <param name="moment">The moment.</param>
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/// <returns>The result.</returns>
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private static long Bottom(Box cube, int direction, long[] moment) |
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{ |
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switch (direction) |
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{ |
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// Red
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case 0: |
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return -moment[GetPalleteIndex(cube.R0, cube.G1, cube.B1, cube.A1)] |
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+ moment[GetPalleteIndex(cube.R0, cube.G1, cube.B1, cube.A0)] |
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+ moment[GetPalleteIndex(cube.R0, cube.G1, cube.B0, cube.A1)] |
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- moment[GetPalleteIndex(cube.R0, cube.G1, cube.B0, cube.A0)] |
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+ moment[GetPalleteIndex(cube.R0, cube.G0, cube.B1, cube.A1)] |
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- moment[GetPalleteIndex(cube.R0, cube.G0, cube.B1, cube.A0)] |
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- moment[GetPalleteIndex(cube.R0, cube.G0, cube.B0, cube.A1)] |
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+ moment[GetPalleteIndex(cube.R0, cube.G0, cube.B0, cube.A0)]; |
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// Green
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case 1: |
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return -moment[GetPalleteIndex(cube.R1, cube.G0, cube.B1, cube.A1)] |
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+ moment[GetPalleteIndex(cube.R1, cube.G0, cube.B1, cube.A0)] |
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+ moment[GetPalleteIndex(cube.R1, cube.G0, cube.B0, cube.A1)] |
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- moment[GetPalleteIndex(cube.R1, cube.G0, cube.B0, cube.A0)] |
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+ moment[GetPalleteIndex(cube.R0, cube.G0, cube.B1, cube.A1)] |
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- moment[GetPalleteIndex(cube.R0, cube.G0, cube.B1, cube.A0)] |
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- moment[GetPalleteIndex(cube.R0, cube.G0, cube.B0, cube.A1)] |
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+ moment[GetPalleteIndex(cube.R0, cube.G0, cube.B0, cube.A0)]; |
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// Blue
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case 2: |
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return -moment[GetPalleteIndex(cube.R1, cube.G1, cube.B0, cube.A1)] |
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+ moment[GetPalleteIndex(cube.R1, cube.G1, cube.B0, cube.A0)] |
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+ moment[GetPalleteIndex(cube.R1, cube.G0, cube.B0, cube.A1)] |
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- moment[GetPalleteIndex(cube.R1, cube.G0, cube.B0, cube.A0)] |
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+ moment[GetPalleteIndex(cube.R0, cube.G1, cube.B0, cube.A1)] |
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- moment[GetPalleteIndex(cube.R0, cube.G1, cube.B0, cube.A0)] |
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- moment[GetPalleteIndex(cube.R0, cube.G0, cube.B0, cube.A1)] |
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+ moment[GetPalleteIndex(cube.R0, cube.G0, cube.B0, cube.A0)]; |
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// Alpha
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case 3: |
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return -moment[GetPalleteIndex(cube.R1, cube.G1, cube.B1, cube.A0)] |
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+ moment[GetPalleteIndex(cube.R1, cube.G1, cube.B0, cube.A0)] |
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+ moment[GetPalleteIndex(cube.R1, cube.G0, cube.B1, cube.A0)] |
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- moment[GetPalleteIndex(cube.R1, cube.G0, cube.B0, cube.A0)] |
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+ moment[GetPalleteIndex(cube.R0, cube.G1, cube.B1, cube.A0)] |
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- moment[GetPalleteIndex(cube.R0, cube.G1, cube.B0, cube.A0)] |
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- moment[GetPalleteIndex(cube.R0, cube.G0, cube.B1, cube.A0)] |
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+ moment[GetPalleteIndex(cube.R0, cube.G0, cube.B0, cube.A0)]; |
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default: |
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throw new ArgumentOutOfRangeException(nameof(direction)); |
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} |
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} |
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/// <summary>
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/// Computes remainder of Volume(cube, moment), substituting position for r1, g1, or b1 (depending on direction).
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/// </summary>
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/// <param name="cube">The cube.</param>
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/// <param name="direction">The direction.</param>
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/// <param name="position">The position.</param>
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/// <param name="moment">The moment.</param>
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/// <returns>The result.</returns>
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private static long Top(Box cube, int direction, int position, long[] moment) |
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{ |
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switch (direction) |
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{ |
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// Red
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case 0: |
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return moment[GetPalleteIndex(position, cube.G1, cube.B1, cube.A1)] |
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- moment[GetPalleteIndex(position, cube.G1, cube.B1, cube.A0)] |
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- moment[GetPalleteIndex(position, cube.G1, cube.B0, cube.A1)] |
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+ moment[GetPalleteIndex(position, cube.G1, cube.B0, cube.A0)] |
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- moment[GetPalleteIndex(position, cube.G0, cube.B1, cube.A1)] |
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+ moment[GetPalleteIndex(position, cube.G0, cube.B1, cube.A0)] |
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+ moment[GetPalleteIndex(position, cube.G0, cube.B0, cube.A1)] |
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- moment[GetPalleteIndex(position, cube.G0, cube.B0, cube.A0)]; |
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// Green
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case 1: |
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return moment[GetPalleteIndex(cube.R1, position, cube.B1, cube.A1)] |
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- moment[GetPalleteIndex(cube.R1, position, cube.B1, cube.A0)] |
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- moment[GetPalleteIndex(cube.R1, position, cube.B0, cube.A1)] |
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+ moment[GetPalleteIndex(cube.R1, position, cube.B0, cube.A0)] |
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- moment[GetPalleteIndex(cube.R0, position, cube.B1, cube.A1)] |
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+ moment[GetPalleteIndex(cube.R0, position, cube.B1, cube.A0)] |
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+ moment[GetPalleteIndex(cube.R0, position, cube.B0, cube.A1)] |
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- moment[GetPalleteIndex(cube.R0, position, cube.B0, cube.A0)]; |
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// Blue
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case 2: |
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return moment[GetPalleteIndex(cube.R1, cube.G1, position, cube.A1)] |
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- moment[GetPalleteIndex(cube.R1, cube.G1, position, cube.A0)] |
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- moment[GetPalleteIndex(cube.R1, cube.G0, position, cube.A1)] |
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+ moment[GetPalleteIndex(cube.R1, cube.G0, position, cube.A0)] |
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- moment[GetPalleteIndex(cube.R0, cube.G1, position, cube.A1)] |
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+ moment[GetPalleteIndex(cube.R0, cube.G1, position, cube.A0)] |
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+ moment[GetPalleteIndex(cube.R0, cube.G0, position, cube.A1)] |
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- moment[GetPalleteIndex(cube.R0, cube.G0, position, cube.A0)]; |
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// Alpha
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case 3: |
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return moment[GetPalleteIndex(cube.R1, cube.G1, cube.B1, position)] |
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- moment[GetPalleteIndex(cube.R1, cube.G1, cube.B0, position)] |
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- moment[GetPalleteIndex(cube.R1, cube.G0, cube.B1, position)] |
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+ moment[GetPalleteIndex(cube.R1, cube.G0, cube.B0, position)] |
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- moment[GetPalleteIndex(cube.R0, cube.G1, cube.B1, position)] |
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+ moment[GetPalleteIndex(cube.R0, cube.G1, cube.B0, position)] |
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+ moment[GetPalleteIndex(cube.R0, cube.G0, cube.B1, position)] |
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- moment[GetPalleteIndex(cube.R0, cube.G0, cube.B0, position)]; |
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default: |
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throw new ArgumentOutOfRangeException(nameof(direction)); |
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} |
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} |
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/// <summary>
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/// Clears the tables.
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/// </summary>
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private void Clear() |
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{ |
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Array.Clear(this.vwt, 0, TableLength); |
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Array.Clear(this.vmr, 0, TableLength); |
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Array.Clear(this.vmg, 0, TableLength); |
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Array.Clear(this.vmb, 0, TableLength); |
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Array.Clear(this.vma, 0, TableLength); |
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Array.Clear(this.m2, 0, TableLength); |
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Array.Clear(this.tag, 0, TableLength); |
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} |
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/// <summary>
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/// Builds a 3-D color histogram of <c>counts, r/g/b, c^2</c>.
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/// </summary>
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/// <param name="image">The image.</param>
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private void Build3DHistogram(ImageBase image) |
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{ |
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for (int y = 0; y < image.Height; y++) |
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{ |
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for (int x = 0; x < image.Width; x++) |
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{ |
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Bgra32 color = image[x, y]; |
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byte r = color.R; |
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byte g = color.G; |
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byte b = color.B; |
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byte a = color.A; |
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int inr = r >> (8 - IndexBits); |
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int ing = g >> (8 - IndexBits); |
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int inb = b >> (8 - IndexBits); |
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int ina = a >> (8 - IndexAlphaBits); |
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int ind = GetPalleteIndex(inr + 1, ing + 1, inb + 1, ina + 1); |
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this.vwt[ind]++; |
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this.vmr[ind] += r; |
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this.vmg[ind] += g; |
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this.vmb[ind] += b; |
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this.vma[ind] += a; |
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this.m2[ind] += (r * r) + (g * g) + (b * b) + (a * a); |
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} |
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} |
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} |
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/// <summary>
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/// Converts the histogram into moments so that we can rapidly calculate
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/// the sums of the above quantities over any desired box.
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/// </summary>
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private void Get3DMoments() |
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{ |
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long[] volume = new long[IndexCount * IndexAlphaCount]; |
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long[] volumeR = new long[IndexCount * IndexAlphaCount]; |
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long[] volumeG = new long[IndexCount * IndexAlphaCount]; |
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long[] volumeB = new long[IndexCount * IndexAlphaCount]; |
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long[] volumeA = new long[IndexCount * IndexAlphaCount]; |
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double[] volume2 = new double[IndexCount * IndexAlphaCount]; |
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long[] area = new long[IndexAlphaCount]; |
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long[] areaR = new long[IndexAlphaCount]; |
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long[] areaG = new long[IndexAlphaCount]; |
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long[] areaB = new long[IndexAlphaCount]; |
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long[] areaA = new long[IndexAlphaCount]; |
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double[] area2 = new double[IndexAlphaCount]; |
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for (int r = 1; r < IndexCount; r++) |
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{ |
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Array.Clear(volume, 0, IndexCount * IndexAlphaCount); |
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Array.Clear(volumeR, 0, IndexCount * IndexAlphaCount); |
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Array.Clear(volumeG, 0, IndexCount * IndexAlphaCount); |
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Array.Clear(volumeB, 0, IndexCount * IndexAlphaCount); |
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Array.Clear(volumeA, 0, IndexCount * IndexAlphaCount); |
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Array.Clear(volume2, 0, IndexCount * IndexAlphaCount); |
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|
|||
for (int g = 1; g < IndexCount; g++) |
|||
{ |
|||
Array.Clear(area, 0, IndexAlphaCount); |
|||
Array.Clear(areaR, 0, IndexAlphaCount); |
|||
Array.Clear(areaG, 0, IndexAlphaCount); |
|||
Array.Clear(areaB, 0, IndexAlphaCount); |
|||
Array.Clear(areaA, 0, IndexAlphaCount); |
|||
Array.Clear(area2, 0, IndexAlphaCount); |
|||
|
|||
for (int b = 1; b < IndexCount; b++) |
|||
{ |
|||
long line = 0; |
|||
long lineR = 0; |
|||
long lineG = 0; |
|||
long lineB = 0; |
|||
long lineA = 0; |
|||
double line2 = 0; |
|||
|
|||
for (int a = 1; a < IndexAlphaCount; a++) |
|||
{ |
|||
int ind1 = GetPalleteIndex(r, g, b, a); |
|||
|
|||
line += this.vwt[ind1]; |
|||
lineR += this.vmr[ind1]; |
|||
lineG += this.vmg[ind1]; |
|||
lineB += this.vmb[ind1]; |
|||
lineA += this.vma[ind1]; |
|||
line2 += this.m2[ind1]; |
|||
|
|||
area[a] += line; |
|||
areaR[a] += lineR; |
|||
areaG[a] += lineG; |
|||
areaB[a] += lineB; |
|||
areaA[a] += lineA; |
|||
area2[a] += line2; |
|||
|
|||
int inv = (b * IndexAlphaCount) + a; |
|||
|
|||
volume[inv] += area[a]; |
|||
volumeR[inv] += areaR[a]; |
|||
volumeG[inv] += areaG[a]; |
|||
volumeB[inv] += areaB[a]; |
|||
volumeA[inv] += areaA[a]; |
|||
volume2[inv] += area2[a]; |
|||
|
|||
int ind2 = ind1 - GetPalleteIndex(1, 0, 0, 0); |
|||
|
|||
this.vwt[ind1] = this.vwt[ind2] + volume[inv]; |
|||
this.vmr[ind1] = this.vmr[ind2] + volumeR[inv]; |
|||
this.vmg[ind1] = this.vmg[ind2] + volumeG[inv]; |
|||
this.vmb[ind1] = this.vmb[ind2] + volumeB[inv]; |
|||
this.vma[ind1] = this.vma[ind2] + volumeA[inv]; |
|||
this.m2[ind1] = this.m2[ind2] + volume2[inv]; |
|||
} |
|||
} |
|||
} |
|||
} |
|||
} |
|||
|
|||
/// <summary>
|
|||
/// Computes the weighted variance of a box cube.
|
|||
/// </summary>
|
|||
/// <param name="cube">The cube.</param>
|
|||
/// <returns>The <see cref="double"/>.</returns>
|
|||
private double Variance(Box cube) |
|||
{ |
|||
double dr = Volume(cube, this.vmr); |
|||
double dg = Volume(cube, this.vmg); |
|||
double db = Volume(cube, this.vmb); |
|||
double da = Volume(cube, this.vma); |
|||
|
|||
double xx = |
|||
this.m2[GetPalleteIndex(cube.R1, cube.G1, cube.B1, cube.A1)] |
|||
- this.m2[GetPalleteIndex(cube.R1, cube.G1, cube.B1, cube.A0)] |
|||
- this.m2[GetPalleteIndex(cube.R1, cube.G1, cube.B0, cube.A1)] |
|||
+ this.m2[GetPalleteIndex(cube.R1, cube.G1, cube.B0, cube.A0)] |
|||
- this.m2[GetPalleteIndex(cube.R1, cube.G0, cube.B1, cube.A1)] |
|||
+ this.m2[GetPalleteIndex(cube.R1, cube.G0, cube.B1, cube.A0)] |
|||
+ this.m2[GetPalleteIndex(cube.R1, cube.G0, cube.B0, cube.A1)] |
|||
- this.m2[GetPalleteIndex(cube.R1, cube.G0, cube.B0, cube.A0)] |
|||
- this.m2[GetPalleteIndex(cube.R0, cube.G1, cube.B1, cube.A1)] |
|||
+ this.m2[GetPalleteIndex(cube.R0, cube.G1, cube.B1, cube.A0)] |
|||
+ this.m2[GetPalleteIndex(cube.R0, cube.G1, cube.B0, cube.A1)] |
|||
- this.m2[GetPalleteIndex(cube.R0, cube.G1, cube.B0, cube.A0)] |
|||
+ this.m2[GetPalleteIndex(cube.R0, cube.G0, cube.B1, cube.A1)] |
|||
- this.m2[GetPalleteIndex(cube.R0, cube.G0, cube.B1, cube.A0)] |
|||
- this.m2[GetPalleteIndex(cube.R0, cube.G0, cube.B0, cube.A1)] |
|||
+ this.m2[GetPalleteIndex(cube.R0, cube.G0, cube.B0, cube.A0)]; |
|||
|
|||
return xx - (((dr * dr) + (dg * dg) + (db * db) + (da * da)) / Volume(cube, this.vwt)); |
|||
} |
|||
|
|||
/// <summary>
|
|||
/// We want to minimize the sum of the variances of two sub-boxes.
|
|||
/// The sum(c^2) terms can be ignored since their sum over both sub-boxes
|
|||
/// is the same (the sum for the whole box) no matter where we split.
|
|||
/// The remaining terms have a minus sign in the variance formula,
|
|||
/// so we drop the minus sign and maximize the sum of the two terms.
|
|||
/// </summary>
|
|||
/// <param name="cube">The cube.</param>
|
|||
/// <param name="direction">The direction.</param>
|
|||
/// <param name="first">The first position.</param>
|
|||
/// <param name="last">The last position.</param>
|
|||
/// <param name="cut">The cutting point.</param>
|
|||
/// <param name="wholeR">The whole red.</param>
|
|||
/// <param name="wholeG">The whole green.</param>
|
|||
/// <param name="wholeB">The whole blue.</param>
|
|||
/// <param name="wholeA">The whole alpha.</param>
|
|||
/// <param name="wholeW">The whole weight.</param>
|
|||
/// <returns>The <see cref="double"/>.</returns>
|
|||
private double Maximize(Box cube, int direction, int first, int last, out int cut, double wholeR, double wholeG, double wholeB, double wholeA, double wholeW) |
|||
{ |
|||
long baseR = Bottom(cube, direction, this.vmr); |
|||
long baseG = Bottom(cube, direction, this.vmg); |
|||
long baseB = Bottom(cube, direction, this.vmb); |
|||
long baseA = Bottom(cube, direction, this.vma); |
|||
long baseW = Bottom(cube, direction, this.vwt); |
|||
|
|||
double max = 0.0; |
|||
cut = -1; |
|||
|
|||
for (int i = first; i < last; i++) |
|||
{ |
|||
double halfR = baseR + Top(cube, direction, i, this.vmr); |
|||
double halfG = baseG + Top(cube, direction, i, this.vmg); |
|||
double halfB = baseB + Top(cube, direction, i, this.vmb); |
|||
double halfA = baseA + Top(cube, direction, i, this.vma); |
|||
double halfW = baseW + Top(cube, direction, i, this.vwt); |
|||
|
|||
double temp; |
|||
|
|||
if (Math.Abs(halfW) < Epsilon) |
|||
{ |
|||
continue; |
|||
} |
|||
|
|||
temp = ((halfR * halfR) + (halfG * halfG) + (halfB * halfB) + (halfA * halfA)) / halfW; |
|||
|
|||
halfR = wholeR - halfR; |
|||
halfG = wholeG - halfG; |
|||
halfB = wholeB - halfB; |
|||
halfA = wholeA - halfA; |
|||
halfW = wholeW - halfW; |
|||
|
|||
if (Math.Abs(halfW) < Epsilon) |
|||
{ |
|||
continue; |
|||
} |
|||
|
|||
temp += ((halfR * halfR) + (halfG * halfG) + (halfB * halfB) + (halfA * halfA)) / halfW; |
|||
|
|||
if (temp > max) |
|||
{ |
|||
max = temp; |
|||
cut = i; |
|||
} |
|||
} |
|||
|
|||
return max; |
|||
} |
|||
|
|||
/// <summary>
|
|||
/// Cuts a box.
|
|||
/// </summary>
|
|||
/// <param name="set1">The first set.</param>
|
|||
/// <param name="set2">The second set.</param>
|
|||
/// <returns>Returns a value indicating whether the box has been split.</returns>
|
|||
private bool Cut(Box set1, Box set2) |
|||
{ |
|||
double wholeR = Volume(set1, this.vmr); |
|||
double wholeG = Volume(set1, this.vmg); |
|||
double wholeB = Volume(set1, this.vmb); |
|||
double wholeA = Volume(set1, this.vma); |
|||
double wholeW = Volume(set1, this.vwt); |
|||
|
|||
int cutr; |
|||
int cutg; |
|||
int cutb; |
|||
int cuta; |
|||
|
|||
double maxr = this.Maximize(set1, 0, set1.R0 + 1, set1.R1, out cutr, wholeR, wholeG, wholeB, wholeA, wholeW); |
|||
double maxg = this.Maximize(set1, 1, set1.G0 + 1, set1.G1, out cutg, wholeR, wholeG, wholeB, wholeA, wholeW); |
|||
double maxb = this.Maximize(set1, 2, set1.B0 + 1, set1.B1, out cutb, wholeR, wholeG, wholeB, wholeA, wholeW); |
|||
double maxa = this.Maximize(set1, 3, set1.A0 + 1, set1.A1, out cuta, wholeR, wholeG, wholeB, wholeA, wholeW); |
|||
|
|||
int dir; |
|||
|
|||
if ((maxr >= maxg) && (maxr >= maxb) && (maxr >= maxa)) |
|||
{ |
|||
dir = 0; |
|||
|
|||
if (cutr < 0) |
|||
{ |
|||
return false; |
|||
} |
|||
} |
|||
else if ((maxg >= maxr) && (maxg >= maxb) && (maxg >= maxa)) |
|||
{ |
|||
dir = 1; |
|||
} |
|||
else if ((maxb >= maxr) && (maxb >= maxg) && (maxb >= maxa)) |
|||
{ |
|||
dir = 2; |
|||
} |
|||
else |
|||
{ |
|||
dir = 3; |
|||
} |
|||
|
|||
set2.R1 = set1.R1; |
|||
set2.G1 = set1.G1; |
|||
set2.B1 = set1.B1; |
|||
set2.A1 = set1.A1; |
|||
|
|||
switch (dir) |
|||
{ |
|||
// Red
|
|||
case 0: |
|||
set2.R0 = set1.R1 = cutr; |
|||
set2.G0 = set1.G0; |
|||
set2.B0 = set1.B0; |
|||
set2.A0 = set1.A0; |
|||
break; |
|||
|
|||
// Green
|
|||
case 1: |
|||
set2.G0 = set1.G1 = cutg; |
|||
set2.R0 = set1.R0; |
|||
set2.B0 = set1.B0; |
|||
set2.A0 = set1.A0; |
|||
break; |
|||
|
|||
// Blue
|
|||
case 2: |
|||
set2.B0 = set1.B1 = cutb; |
|||
set2.R0 = set1.R0; |
|||
set2.G0 = set1.G0; |
|||
set2.A0 = set1.A0; |
|||
break; |
|||
|
|||
// Alpha
|
|||
case 3: |
|||
set2.A0 = set1.A1 = cuta; |
|||
set2.R0 = set1.R0; |
|||
set2.G0 = set1.G0; |
|||
set2.B0 = set1.B0; |
|||
break; |
|||
} |
|||
|
|||
set1.Volume = (set1.R1 - set1.R0) * (set1.G1 - set1.G0) * (set1.B1 - set1.B0) * (set1.A1 - set1.A0); |
|||
set2.Volume = (set2.R1 - set2.R0) * (set2.G1 - set2.G0) * (set2.B1 - set2.B0) * (set2.A1 - set2.A0); |
|||
|
|||
return true; |
|||
} |
|||
|
|||
/// <summary>
|
|||
/// Marks a color space tag.
|
|||
/// </summary>
|
|||
/// <param name="cube">The cube.</param>
|
|||
/// <param name="label">A label.</param>
|
|||
private void Mark(Box cube, byte label) |
|||
{ |
|||
for (int r = cube.R0 + 1; r <= cube.R1; r++) |
|||
{ |
|||
for (int g = cube.G0 + 1; g <= cube.G1; g++) |
|||
{ |
|||
for (int b = cube.B0 + 1; b <= cube.B1; b++) |
|||
{ |
|||
for (int a = cube.A0 + 1; a <= cube.A1; a++) |
|||
{ |
|||
this.tag[GetPalleteIndex(r, g, b, a)] = label; |
|||
} |
|||
} |
|||
} |
|||
} |
|||
} |
|||
|
|||
/// <summary>
|
|||
/// Builds the cube.
|
|||
/// </summary>
|
|||
/// <param name="cube">The cube.</param>
|
|||
/// <param name="colorCount">The color count.</param>
|
|||
private void BuildCube(out Box[] cube, ref int colorCount) |
|||
{ |
|||
cube = new Box[colorCount]; |
|||
double[] vv = new double[colorCount]; |
|||
|
|||
for (int i = 0; i < colorCount; i++) |
|||
{ |
|||
cube[i] = new Box(); |
|||
} |
|||
|
|||
cube[0].R0 = cube[0].G0 = cube[0].B0 = cube[0].A0 = 0; |
|||
cube[0].R1 = cube[0].G1 = cube[0].B1 = IndexCount - 1; |
|||
cube[0].A1 = IndexAlphaCount - 1; |
|||
|
|||
int next = 0; |
|||
|
|||
for (int i = 1; i < colorCount; i++) |
|||
{ |
|||
if (this.Cut(cube[next], cube[i])) |
|||
{ |
|||
vv[next] = cube[next].Volume > 1 ? this.Variance(cube[next]) : 0.0; |
|||
vv[i] = cube[i].Volume > 1 ? this.Variance(cube[i]) : 0.0; |
|||
} |
|||
else |
|||
{ |
|||
vv[next] = 0.0; |
|||
i--; |
|||
} |
|||
|
|||
next = 0; |
|||
|
|||
double temp = vv[0]; |
|||
for (int k = 1; k <= i; k++) |
|||
{ |
|||
if (vv[k] > temp) |
|||
{ |
|||
temp = vv[k]; |
|||
next = k; |
|||
} |
|||
} |
|||
|
|||
if (temp <= 0.0) |
|||
{ |
|||
colorCount = i + 1; |
|||
break; |
|||
} |
|||
} |
|||
} |
|||
|
|||
/// <summary>
|
|||
/// Generates the quantized result.
|
|||
/// </summary>
|
|||
/// <param name="image">The image.</param>
|
|||
/// <param name="colorCount">The color count.</param>
|
|||
/// <param name="cube">The cube.</param>
|
|||
/// <returns>The result.</returns>
|
|||
private QuantizedImage GenerateResult(ImageBase image, int colorCount, Box[] cube) |
|||
{ |
|||
List<Bgra32> pallette = new List<Bgra32>(); |
|||
byte[] pixels = new byte[image.Width * image.Height]; |
|||
int transparentIndex = 0; |
|||
|
|||
for (int k = 0; k < colorCount; k++) |
|||
{ |
|||
this.Mark(cube[k], (byte)k); |
|||
|
|||
double weight = Volume(cube[k], this.vwt); |
|||
|
|||
if (Math.Abs(weight) > Epsilon) |
|||
{ |
|||
byte r = (byte)(Volume(cube[k], this.vmr) / weight); |
|||
byte g = (byte)(Volume(cube[k], this.vmg) / weight); |
|||
byte b = (byte)(Volume(cube[k], this.vmb) / weight); |
|||
byte a = (byte)(Volume(cube[k], this.vma) / weight); |
|||
|
|||
var color = new Bgra32(b, g, r, a); |
|||
|
|||
if (color == Bgra32.Empty) |
|||
{ |
|||
transparentIndex = k; |
|||
} |
|||
|
|||
pallette.Add(color); |
|||
} |
|||
else |
|||
{ |
|||
pallette.Add(Bgra32.Empty); |
|||
transparentIndex = k; |
|||
} |
|||
} |
|||
|
|||
// TODO: Optimize here.
|
|||
int i = 0; |
|||
for (int y = 0; y < image.Height; y++) |
|||
{ |
|||
for (int x = 0; x < image.Width; x++) |
|||
{ |
|||
Bgra32 color = image[x, y]; |
|||
int a = color.A >> (8 - IndexAlphaBits); |
|||
int r = color.R >> (8 - IndexBits); |
|||
int g = color.G >> (8 - IndexBits); |
|||
int b = color.B >> (8 - IndexBits); |
|||
|
|||
int ind = GetPalleteIndex(r + 1, g + 1, b + 1, a + 1); |
|||
pixels[i++] = this.tag[ind]; |
|||
} |
|||
} |
|||
|
|||
return new QuantizedImage(image.Width, image.Height, pallette.ToArray(), pixels, transparentIndex); |
|||
} |
|||
} |
|||
} |
|||
Loading…
Reference in new issue