IndexedColor.cs

/*
 * NanoXLSX is a small .NET library to generate and read XLSX (Microsoft Excel 2007 or newer) files in an easy and native way
 * Copyright Raphael Stoeckli © 2026
 * This library is licensed under the MIT License.
 * You find a copy of the license in project folder or on: http://opensource.org/licenses/MIT
 */
 
using NanoXLSX.Exceptions;
using NanoXLSX.Interfaces;
using NanoXLSX.Utils;
using static NanoXLSX.Colors.IndexedColor;
 
namespace NanoXLSX.Colors
{
    public class IndexedColor : ITypedColor<Value>
    {
        public enum Value : byte
        {
            Black0 = 0,
            White1 = 1,
            Red2 = 2,
            BrightGreen3 = 3,
            Blue4 = 4,
            Yellow5 = 5,
            Magenta6 = 6,
            Cyan7 = 7,
            Black = 8,
            White = 9,
            Red = 10,
            BrightGreen = 11,
            Blue = 12,
            Yellow = 13,
            Magenta = 14,
            Cyan = 15,
            DarkRed = 16,
            DarkGreen = 17,
            DarkBlue = 18,
            Olive = 19,
            Purple = 20,
            Teal = 21,
            LightGray = 22,
            Gray = 23,
            LightCornflowerBlue = 24,
            DarkRose = 25,
            LightYellow = 26,
            LightCyan = 27,
            DarkPurple = 28,
            Salmon = 29,
            MediumBlue = 30,
            LightLavender = 31,
            Navy = 32,
            StrongMagenta = 33,
            StrongYellow = 34,
            StrongCyan = 35,
            DarkViolet = 36,
            DarkMaroon = 37,
            DarkTeal = 38,
            PureBlue = 39,
            SkyBlue = 40,
            PaleCyan = 41,
            LightMint = 42,
            PastelYellow = 43,
            LightSkyBlue = 44,
            Rose = 45,
            Lavender = 46,
            Peach = 47,
            RoyalBlue = 48,
            Turquoise = 49,
            LightOlive = 50,
            Gold = 51,
            Orange = 52,
            DarkOrange = 53,
            BlueGray = 54,
            MediumGray = 55,
            DarkSlateBlue = 56,
            SeaGreen = 57,
            VeryDarkGreen = 58,
            DarkOlive = 59,
            Brown = 60,
            DarkRoseDuplicate = 61,
            Indigo = 62,
            VeryDarkGray = 63,
            SystemForeground = 64,
            SystemBackground = 65
        }

        public const Value DefaultIndexedColor = Value.SystemForeground;
        public const string DefaultSystemForegroundColorArgb = "FF000000";
        public const string DefaultSystemBackgroundColorArgb = "FFFFFFFF";
 

        public Value ColorValue { get; set; }

        public string StringValue => ParserUtils.ToString((int)ColorValue);

        public IndexedColor()
        {
            ColorValue = DefaultIndexedColor;
        }

        public IndexedColor(Value color)
        {
            ColorValue = color;
        }

        public IndexedColor(int colorIndex)
        {
            if (colorIndex < 0 || colorIndex > 65)
            {
                throw new StyleException("Indexed color value must be between 0 and 65.");
            }
            ColorValue = (Value)colorIndex;
        }

        public string GetArgbValue()
        {
            return GetArgbValue(ColorValue);
        }

        public SrgbColor GetSrgbColor()
        {
            return new SrgbColor(GetArgbValue());
        }

        public static string GetArgbValue(Value indexedValue)
        {
            switch (indexedValue)
            {
                // 0–7 (duplicates of 8–15)
                case Value.Black0:
                case Value.Black:
                    return "FF000000";
 
                case Value.White1:
                case Value.White:
                    return "FFFFFFFF";
 
                case Value.Red2:
                case Value.Red:
                    return "FFFF0000";
 
                case Value.BrightGreen3:
                case Value.BrightGreen:
                    return "FF00FF00";
 
                case Value.Blue4:
                case Value.Blue:
                case Value.PureBlue:
                    return "FF0000FF";
 
                case Value.Yellow5:
                case Value.Yellow:
                case Value.StrongYellow:
                    return "FFFFFF00";
 
                case Value.Magenta6:
                case Value.Magenta:
                case Value.StrongMagenta:
                    return "FFFF00FF";
 
                case Value.Cyan7:
                case Value.Cyan:
                case Value.StrongCyan:
                    return "FF00FFFF";
 
                // Extended palette
                case Value.DarkRed:
                case Value.DarkMaroon:
                    return "FF800000";
 
                case Value.DarkGreen:
                    return "FF008000";
 
                case Value.DarkBlue:
                case Value.Navy:
                    return "FF000080";
 
                case Value.Olive:
                    return "FF808000";
 
                case Value.Purple:
                case Value.DarkViolet:
                    return "FF800080";
 
                case Value.Teal:
                case Value.DarkTeal:
                    return "FF008080";
 
                case Value.LightGray:
                    return "FFC0C0C0";
 
                case Value.Gray:
                    return "FF808080";
 
                case Value.LightCornflowerBlue:
                    return "FF9999FF";
 
                case Value.DarkRose:
                case Value.DarkRoseDuplicate:
                    return "FF993366";
 
                case Value.LightYellow:
                    return "FFFFFFCC";
 
                case Value.LightCyan:
                case Value.PaleCyan:
                    return "FFCCFFFF";
 
                case Value.DarkPurple:
                    return "FF660066";
 
                case Value.Salmon:
                    return "FFFF8080";
 
                case Value.MediumBlue:
                    return "FF0066CC";
 
                case Value.LightLavender:
                    return "FFCCCCFF";
 
                case Value.SkyBlue:
                    return "FF00CCFF";
 
                case Value.LightMint:
                    return "FFCCFFCC";
 
                case Value.PastelYellow:
                    return "FFFFFF99";
 
                case Value.LightSkyBlue:
                    return "FF99CCFF";
 
                case Value.Rose:
                    return "FFFF99CC";
 
                case Value.Lavender:
                    return "FFCC99FF";
 
                case Value.Peach:
                    return "FFFFCC99";
 
                case Value.RoyalBlue:
                    return "FF3366FF";
 
                case Value.Turquoise:
                    return "FF33CCCC";
 
                case Value.LightOlive:
                    return "FF99CC00";
 
                case Value.Gold:
                    return "FFFFCC00";
 
                case Value.Orange:
                    return "FFFF9900";
 
                case Value.DarkOrange:
                    return "FFFF6600";
 
                case Value.BlueGray:
                    return "FF666699";
 
                case Value.MediumGray:
                    return "FF969696";
 
                case Value.DarkSlateBlue:
                    return "FF003366";
 
                case Value.SeaGreen:
                    return "FF339966";
 
                case Value.VeryDarkGreen:
                    return "FF003300";
 
                case Value.DarkOlive:
                    return "FF333300";
 
                case Value.Brown:
                    return "FF993300";
 
                case Value.Indigo:
                    return "FF333399";
 
                case Value.VeryDarkGray:
                    return "FF333333";
 
                case Value.SystemBackground:
                    // Excel default: white background
                    return DefaultSystemBackgroundColorArgb;
 
                default:
                    // Excel default: black text
                    return DefaultSystemForegroundColorArgb;
            }
        }

        public override bool Equals(object obj)
        {
            return obj is IndexedColor color &&
                   ColorValue == color.ColorValue;
        }

        public override int GetHashCode()
        {
            return 800285905 + ColorValue.GetHashCode();
        }

        public static implicit operator IndexedColor(Value value)
        {
            return new IndexedColor(value);
        }
    }
}