EPPlus/Style/ExcelColor.cs

/*******************************************************************************
 * You may amend and distribute as you like, but don't remove this header!
 *
 * EPPlus provides server-side generation of Excel 2007/2010 spreadsheets.
 * See http://www.codeplex.com/EPPlus for details.
 *
 * Copyright (C) 2011  Jan Källman
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.

 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  
 * See the GNU Lesser General Public License for more details.
 *
 * The GNU Lesser General Public License can be viewed at http://www.opensource.org/licenses/lgpl-license.php
 * If you unfamiliar with this license or have questions about it, here is an http://www.gnu.org/licenses/gpl-faq.html
 *
 * All code and executables are provided "as is" with no warranty either express or implied. 
 * The author accepts no liability for any damage or loss of business that this product may cause.
 *
 * Code change notes:
 * 
 * Author							Change						Date
 * ******************************************************************************
 * Jan Källman		                Initial Release		        2009-10-01
 * Jan Källman		License changed GPL-->LGPL 2011-12-16
 *******************************************************************************/
using System;
using System.Collections.Generic;
using System.Text;
using OfficeOpenXml.Style.XmlAccess;
using System.Drawing;

namespace OfficeOpenXml.Style
{
    /// <summary>
    /// Color for cellstyling
    /// </summary>
    public sealed class ExcelColor :  StyleBase
    {
        eStyleClass _cls;
        StyleBase _parent;
        internal ExcelColor(ExcelStyles styles, OfficeOpenXml.XmlHelper.ChangedEventHandler ChangedEvent, int worksheetID, string address, eStyleClass cls, StyleBase parent) : 
            base(styles, ChangedEvent, worksheetID, address)
            
        {
            _parent = parent;
            _cls = cls;
        }
        /// <summary>
        /// The theme color
        /// </summary>
        public string Theme
        {
            get
            {
                return GetSource().Theme;
            }
        }
        /// <summary>
        /// The tint value
        /// </summary>
        public decimal Tint
        {
            get
            {
                return GetSource().Tint;
            }
            set
            {
                if (value > 1 || value < -1)
                {
                    throw (new ArgumentOutOfRangeException("Value must be between -1 and 1"));
                }
                _ChangedEvent(this, new StyleChangeEventArgs(_cls, eStyleProperty.Tint, value, _positionID, _address));
            }
        }
        /// <summary>
        /// The RGB value
        /// </summary>
        public string Rgb
        {
            get
            {
                return GetSource().Rgb;
            }
            internal set
            {
                _ChangedEvent(this, new StyleChangeEventArgs(_cls, eStyleProperty.Color, value, _positionID, _address));
            }
        }
        /// <summary>
        /// The indexed color number.
        /// </summary>
        public int Indexed
        {
            get
            {
                return GetSource().Indexed;
            }
            set
            {
                _ChangedEvent(this, new StyleChangeEventArgs(_cls, eStyleProperty.IndexedColor, value, _positionID, _address));
            }
        }
        /// <summary>
        /// Set the color of the object
        /// </summary>
        /// <param name="color">The color</param>
        public void SetColor(Color color)
        {
            Rgb = color.ToArgb().ToString("X");
        }


        internal override string Id
        {
            get 
            {
                return Theme + Tint + Rgb + Indexed;
            }
        }
        private ExcelColorXml GetSource()
        {
            Index = _parent.Index < 0 ? 0 : _parent.Index;
            switch(_cls)
            {
                case eStyleClass.FillBackgroundColor:
                    return _styles.Fills[Index].BackgroundColor;
                case eStyleClass.FillPatternColor:
                    return _styles.Fills[Index].PatternColor;
                case eStyleClass.Font:
                    return _styles.Fonts[Index].Color;
                case eStyleClass.BorderLeft:
                    return _styles.Borders[Index].Left.Color;
                case eStyleClass.BorderTop:
                    return _styles.Borders[Index].Top.Color;
                case eStyleClass.BorderRight:
                    return _styles.Borders[Index].Right.Color;
                case eStyleClass.BorderBottom:
                    return _styles.Borders[Index].Bottom.Color;
                case eStyleClass.BorderDiagonal:
                    return _styles.Borders[Index].Diagonal.Color;
                default:
                    throw(new Exception("Invalid style-class for Color"));
            }
        }
        internal override void SetIndex(int index)
        {
            _parent.Index = index;
        }
        /// <summary>
        /// Return the RGB value for the color object that uses the Indexed or Tint property
        /// </summary>
        /// <param name="theColor">The color object</param>
        /// <returns>The RGB color starting with a #</returns>
        public string LookupColor(ExcelColor theColor)
        {
            //Thanks to neaves for contributing this method.
            int iTint = 0;
            string translatedRGB = "";

            // reference extracted from ECMA-376, Part 4, Section 3.8.26
            string[] rgbLookup =
            {
                "#FF000000", // 0
                "#FFFFFFFF",
                "#FFFF0000",
                "#FF00FF00",
                "#FF0000FF",
                "#FFFFFF00",
                "#FFFF00FF",
                "#FF00FFFF",
                "#FF000000", // 8
                "#FFFFFFFF",
                "#FFFF0000",
                "#FF00FF00",
                "#FF0000FF",
                "#FFFFFF00",
                "#FFFF00FF",
                "#FF00FFFF",
                "#FF800000",
                "#FF008000",
                "#FF000080",
                "#FF808000",
                "#FF800080",
                "#FF008080",
                "#FFC0C0C0",
                "#FF808080",
                "#FF9999FF",
                "#FF993366",
                "#FFFFFFCC",
                "#FFCCFFFF",
                "#FF660066",
                "#FFFF8080",
                "#FF0066CC",
                "#FFCCCCFF",
                "#FF000080",
                "#FFFF00FF",
                "#FFFFFF00",
                "#FF00FFFF",
                "#FF800080",
                "#FF800000",
                "#FF008080",
                "#FF0000FF",
                "#FF00CCFF",
                "#FFCCFFFF",
                "#FFCCFFCC",
                "#FFFFFF99",
                "#FF99CCFF",
                "#FFFF99CC",
                "#FFCC99FF",
                "#FFFFCC99",
                "#FF3366FF",
                "#FF33CCCC",
                "#FF99CC00",
                "#FFFFCC00",
                "#FFFF9900",
                "#FFFF6600",
                "#FF666699",
                "#FF969696",
                "#FF003366",
                "#FF339966",
                "#FF003300",
                "#FF333300",
                "#FF993300",
                "#FF993366",
                "#FF333399",
                "#FF333333", // 63
            };

            if ((0 <= theColor.Indexed) && (rgbLookup.Length > theColor.Indexed))
            {
                // coloring by pre-set color codes
                translatedRGB = rgbLookup[theColor.Indexed];
            }
            else if (null != theColor.Rgb && 0 < theColor.Rgb.Length)
            {
                // coloring by RGB value ("FFRRGGBB")
                translatedRGB = "#" + theColor.Rgb;
            }
            else
            {
                // coloring by shades of grey (-1 -> 0)
                iTint = ((int)(theColor.Tint * 160) + 0x80);
                translatedRGB = ((int)(decimal.Round(theColor.Tint * -512))).ToString("X");
                translatedRGB = "#FF" + translatedRGB + translatedRGB + translatedRGB;
            }

            return translatedRGB;
        }
    }
}