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Former-commit-id: 69da68a4a3d8b6a1b0e0ea0f980b90c1f76a5c27 Former-commit-id: 7d3352f72d9aeae1e9a6a37366ef87af6809f3cf Former-commit-id: df1f8fe540d0cdf3548133acd57693bbda7a9dbcpull/1/head
James Jackson-South
10 years ago
7 changed files with 415 additions and 111 deletions
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// <copyright file="ColorConstants.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 |
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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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/// Provides useful color definitions.
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/// </summary>
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public static class ColorConstants |
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{ |
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/// <summary>
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/// Provides a lazy, one time method of returning the colors.
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/// </summary>
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private static readonly Lazy<Color[]> SafeColors = new Lazy<Color[]>(GetWebSafeColors); |
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/// <summary>
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/// Gets a collection of named, web safe, colors as defined in the CSS Color Module Level 4.
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/// </summary>
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public static Color[] WebSafeColors => SafeColors.Value; |
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/// <summary>
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/// Returns an array of web safe colors.
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/// </summary>
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/// <returns></returns>
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private static Color[] GetWebSafeColors() |
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{ |
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return new List<Color> |
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{ |
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Color.AliceBlue, |
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Color.AntiqueWhite, |
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Color.Aqua, |
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Color.Aquamarine, |
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Color.Azure, |
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Color.Beige, |
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Color.Bisque, |
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Color.Black, |
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Color.BlanchedAlmond, |
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Color.Blue, |
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Color.BlueViolet, |
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Color.Brown, |
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Color.BurlyWood, |
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Color.CadetBlue, |
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Color.Chartreuse, |
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Color.Chocolate, |
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Color.Coral, |
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Color.CornflowerBlue, |
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Color.Cornsilk, |
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Color.Crimson, |
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Color.Cyan, |
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Color.DarkBlue, |
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Color.DarkCyan, |
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Color.DarkGoldenrod, |
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Color.DarkGray, |
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Color.DarkGreen, |
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Color.DarkKhaki, |
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Color.DarkMagenta, |
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Color.DarkOliveGreen, |
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Color.DarkOrange, |
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Color.DarkOrchid, |
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Color.DarkRed, |
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Color.DarkSalmon, |
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Color.DarkSeaGreen, |
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Color.DarkSlateBlue, |
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Color.DarkSlateGray, |
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Color.DarkTurquoise, |
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Color.DarkViolet, |
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Color.DeepPink, |
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Color.DeepSkyBlue, |
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Color.DimGray, |
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Color.DodgerBlue, |
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Color.Firebrick, |
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Color.FloralWhite, |
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Color.ForestGreen, |
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Color.Fuchsia, |
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Color.Gainsboro, |
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Color.GhostWhite, |
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Color.Gold, |
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Color.Goldenrod, |
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Color.Gray, |
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Color.Green, |
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Color.GreenYellow, |
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Color.Honeydew, |
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Color.HotPink, |
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Color.IndianRed, |
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Color.Indigo, |
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Color.Ivory, |
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Color.Khaki, |
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Color.Lavender, |
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Color.LavenderBlush, |
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Color.LawnGreen, |
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Color.LemonChiffon, |
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Color.LightBlue, |
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Color.LightCoral, |
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Color.LightCyan, |
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Color.LightGoldenrodYellow, |
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Color.LightGray, |
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Color.LightGreen, |
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Color.LightPink, |
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Color.LightSalmon, |
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Color.LightSeaGreen, |
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Color.LightSkyBlue, |
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Color.LightSlateGray, |
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Color.LightSteelBlue, |
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Color.LightYellow, |
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Color.Lime, |
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Color.LimeGreen, |
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Color.Linen, |
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Color.Magenta, |
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Color.Maroon, |
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Color.MediumAquamarine, |
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Color.MediumBlue, |
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Color.MediumOrchid, |
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Color.MediumPurple, |
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Color.MediumSeaGreen, |
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Color.MediumSlateBlue, |
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Color.MediumSpringGreen, |
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Color.MediumTurquoise, |
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Color.MediumVioletRed, |
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Color.MidnightBlue, |
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Color.MintCream, |
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Color.MistyRose, |
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Color.Moccasin, |
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Color.NavajoWhite, |
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Color.Navy, |
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Color.OldLace, |
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Color.Olive, |
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Color.OliveDrab, |
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Color.Orange, |
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Color.OrangeRed, |
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Color.Orchid, |
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Color.PaleGoldenrod, |
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Color.PaleGreen, |
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Color.PaleTurquoise, |
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Color.PaleVioletRed, |
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Color.PapayaWhip, |
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Color.PeachPuff, |
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Color.Peru, |
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Color.Pink, |
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Color.Plum, |
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Color.PowderBlue, |
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Color.Purple, |
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Color.RebeccaPurple, |
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Color.Red, |
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Color.RosyBrown, |
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Color.RoyalBlue, |
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Color.SaddleBrown, |
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Color.Salmon, |
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Color.SandyBrown, |
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Color.SeaGreen, |
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Color.SeaShell, |
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Color.Sienna, |
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Color.Silver, |
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Color.SkyBlue, |
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Color.SlateBlue, |
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Color.SlateGray, |
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Color.Snow, |
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Color.SpringGreen, |
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Color.SteelBlue, |
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Color.Tan, |
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Color.Teal, |
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Color.Thistle, |
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Color.Tomato, |
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Color.Transparent, |
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Color.Turquoise, |
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Color.Violet, |
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Color.Wheat, |
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Color.White, |
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Color.WhiteSmoke, |
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Color.Yellow, |
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Color.YellowGreen |
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}.ToArray(); |
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} |
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} |
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} |
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@ -0,0 +1,126 @@ |
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// <copyright file="PaletteQuantizer.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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using System.Linq; |
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/// <summary>
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/// Encapsulates methods to create a quantized image based upon the given palette.
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/// <see href="http://msdn.microsoft.com/en-us/library/aa479306.aspx"/>
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/// </summary>
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public class PaletteQuantizer : Quantizer |
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{ |
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/// <summary>
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/// A lookup table for colors
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/// </summary>
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private readonly Dictionary<int, byte> colorMap = new Dictionary<int, byte>(); |
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/// <summary>
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/// List of all colors in the palette
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/// </summary>
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private Bgra32[] colors; |
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/// <summary>
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/// Initializes a new instance of the <see cref="PaletteQuantizer"/> class.
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/// </summary>
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/// <param name="palette">
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/// The color palette. If none is given this will default to the web safe colors defined
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/// in the CSS Color Module Level 4.
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/// </param>
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public PaletteQuantizer(Color[] palette = null) |
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: base(true) |
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{ |
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this.colors = palette == null |
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? ColorConstants.WebSafeColors.Select(c => (Bgra32)c).ToArray() |
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: palette.Select(c => (Bgra32)c).ToArray(); |
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} |
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/// <inheritdoc/>
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public override QuantizedImage Quantize(ImageBase image, int maxColors) |
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{ |
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Array.Resize(ref this.colors, maxColors.Clamp(1, 256)); |
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return base.Quantize(image, maxColors); |
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} |
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/// <inheritdoc/>
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protected override byte QuantizePixel(Bgra32 pixel) |
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{ |
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byte colorIndex = 0; |
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int colorHash = pixel.Bgra; |
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// Check if the color is in the lookup table
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if (this.colorMap.ContainsKey(colorHash)) |
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{ |
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colorIndex = this.colorMap[colorHash]; |
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} |
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else |
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{ |
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// Not found - loop through the palette and find the nearest match.
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// Firstly check the alpha value - if 0, lookup the transparent color
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if (pixel.A == 0) |
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{ |
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// Transparent. Lookup the first color with an alpha value of 0
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for (int index = 0; index < this.colors.Length; index++) |
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{ |
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if (this.colors[index].A == 0) |
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{ |
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colorIndex = (byte)index; |
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this.TransparentIndex = colorIndex; |
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break; |
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} |
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} |
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} |
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else |
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{ |
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// Not transparent...
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int leastDistance = int.MaxValue; |
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int red = pixel.R; |
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int green = pixel.G; |
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int blue = pixel.B; |
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// Loop through the entire palette, looking for the closest color match
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for (int index = 0; index < this.colors.Length; index++) |
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{ |
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Bgra32 paletteColor = this.colors[index]; |
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int redDistance = paletteColor.R - red; |
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int greenDistance = paletteColor.G - green; |
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int blueDistance = paletteColor.B - blue; |
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int distance = (redDistance * redDistance) + |
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(greenDistance * greenDistance) + |
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(blueDistance * blueDistance); |
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if (distance < leastDistance) |
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{ |
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colorIndex = (byte)index; |
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leastDistance = distance; |
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// And if it's an exact match, exit the loop
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if (distance == 0) |
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{ |
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break; |
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} |
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} |
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} |
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} |
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// Now I have the color, pop it into the cache for next time
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this.colorMap.Add(colorHash, colorIndex); |
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} |
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return colorIndex; |
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} |
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/// <inheritdoc/>
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protected override List<Bgra32> GetPalette() |
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{ |
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return this.colors.ToList(); |
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} |
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} |
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} |
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