ryb2rgb.js

/**************************************************************************************************
 *  Color Space - A RGB to RYB converter.
 *
 *  Copyright (C) 2013 Joshua Gentry
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero General Public License as
 *  published by the Free Software Foundation, either version 3 of the
 *  License, or (at your option) any later version.
 *
 *  This program 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 Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
var RgbRyb = function() {
  throw "Class not initialized yet."
};

/**************************************************************************************************
 * This class deals with RGB and RYG color and converts between them.
 *
 * Member variables:
 * 		pRgb - The color components in RGB format.
 *      pRyg - The color components in RYB format.
 */
function rgb_ryb() {
  var E10001 = "E10001";
  var E10002 = "E10002";
  var E10003 = "E10003";
  var E10004 = "E10004";

  /**********************************************************************************************
   * Construct a new object.
   *
   * @param iRed    The initial red value.
   * @param iGreen  The initial green value.
   * @param iBlue   The initial blue value.
   */
  RgbRyb = function(iRed, iGreen, iBlue) {
    //-----------------------------------------------------------------------------------------

    //-----------------------------------------------------------------------------------------
    // Save the RGB.
    this.setRgb(iRed, iGreen, iBlue);
  }

  /**********************************************************************************************
   * Given a RGB color, calculate the RYB color.  This code was taken from:
   *
   * @param iRed    The current red value.
   * @param iGreen  The current green value.
   * @param iBlue   The current blue value.
   *
   * http://www.insanit.net/tag/rgb-to-ryb/
   *
   * Author: Arah J. Leonard
   * Copyright 01AUG09
   * Distributed under the LGPL - http://www.gnu.org/copyleft/lesser.html
   * ALSO distributed under the The MIT License from the Open Source Initiative (OSI) -
   * http://www.opensource.org/licenses/mit-license.php
   * You may use EITHER of these licenses to work with / distribute this source code.
   * Enjoy!
   */
  RgbRyb.prototype.setRgb = function(iRed, iGreen, iBlue) {
    //-----------------------------------------------------------------------------------------

    //-----------------------------------------------------------------------------------------
    // Save the RGB
    this.pRgb = [iRed, iGreen, iBlue];

    // Remove the white from the color
    var iWhite = Math.min(iRed, iGreen, iBlue);

    iRed -= iWhite;
    iGreen -= iWhite;
    iBlue -= iWhite;

    var iMaxGreen = Math.max(iRed, iGreen, iBlue);

    // Get the yellow out of the red+green

    var iYellow = Math.min(iRed, iGreen);

    iRed -= iYellow;
    iGreen -= iYellow;

    // If this unfortunate conversion combines blue and green, then cut each in half to
    // preserve the value's maximum range.
    if (iBlue > 0 && iGreen > 0) {
      iBlue /= 2;
      iGreen /= 2;
    }

    // Redistribute the remaining green.
    iYellow += iGreen;
    iBlue += iGreen;

    // Normalize to values.
    var iMaxYellow = Math.max(iRed, iYellow, iBlue);

    if (iMaxYellow > 0) {
      var iN = iMaxGreen / iMaxYellow;

      iRed *= iN;
      iYellow *= iN;
      iBlue *= iN;
    }

    // Add the white back in.
    iRed += iWhite;
    iYellow += iWhite;
    iBlue += iWhite;

    this.pRyb = [Math.floor(iRed), Math.floor(iYellow), Math.floor(iBlue)];
  }

  /**********************************************************************************************
   * Given a RYB color, calculate the RGB color.  This code was taken from:
   *
   * @param iRed     The current red value.
   * @param iYellow  The current yellow value.
   * @param iBlue    The current blue value.
   *
   * http://www.insanit.net/tag/rgb-to-ryb/
   *
   * Author: Arah J. Leonard
   * Copyright 01AUG09
   * Distributed under the LGPL - http://www.gnu.org/copyleft/lesser.html
   * ALSO distributed under the The MIT License from the Open Source Initiative (OSI) -
   * http://www.opensource.org/licenses/mit-license.php
   * You may use EITHER of these licenses to work with / distribute this source code.
   * Enjoy!
   */
  RgbRyb.prototype.setRyb = function(iRed, iYellow, iBlue) {
    //-----------------------------------------------------------------------------------------

    //-----------------------------------------------------------------------------------------
    // Save the RYB
    this.pRyb = [iRed, iYellow, iBlue];

    // Remove the whiteness from the color.
    var iWhite = Math.min(iRed, iYellow, iBlue);

    iRed -= iWhite;
    iYellow -= iWhite;
    iBlue -= iWhite;

    var iMaxYellow = Math.max(iRed, iYellow, iBlue);

    // Get the green out of the yellow and blue
    var iGreen = Math.min(iYellow, iBlue);

    iYellow -= iGreen;
    iBlue -= iGreen;

    if (iBlue > 0 && iGreen > 0) {
      iBlue *= 2.0;
      iGreen *= 2.0;
    }

    // Redistribute the remaining yellow.
    iRed += iYellow;
    iGreen += iYellow;

    // Normalize to values.
    var iMaxGreen = Math.max(iRed, iGreen, iBlue);

    if (iMaxGreen > 0) {
      var iN = iMaxYellow / iMaxGreen;

      iRed *= iN;
      iGreen *= iN;
      iBlue *= iN;
    }

    // Add the white back in.
    iRed += iWhite;
    iGreen += iWhite;
    iBlue += iWhite;

    // Save the RGB
    this.pRgb = [Math.floor(iRed), Math.floor(iGreen), Math.floor(iBlue)];
  }

  /**********************************************************************************************
   * Returns the hex code for three digits in an array.
   *
   * @param aData  An array of three integers to return the hex code for.
   *
   * @returns  The hex code for the three numbers
   */
  RgbRyb.prototype.getHexCode = function(aData) {
    //-----------------------------------------------------------------------------------------
    // Create the hex code for the array.
    var szColor = "";
    var szOne = aData[0].toString(16);
    var szTwo = aData[1].toString(16);
    var szThr = aData[2].toString(16);

    if (szOne.length == 1) szColor += "0" + szOne;
    else szColor += szOne;
    if (szTwo.length == 1) szColor += "0" + szTwo;
    else szColor += szTwo;
    if (szThr.length == 1) szColor += "0" + szThr;
    else szColor += szThr;

    return (szColor);
  }

  /**********************************************************************************************
   * Calculate the luminance of the color.
   *
   * @returns The luminance of the color in the range 0 to 255.
   */
  RgbRyb.prototype.getLuminance = function() {
    return (Math.floor(0.2126 * this.pRgb[0] + 0.7152 * this.pRgb[1] + 0.0722 * this.pRgb[2]));
  }

  /**********************************************************************************************
   * Return the RGB color in #RRGGBB format.
   *
   * @returns The RGB color in #RRGGBB.
   */
  RgbRyb.prototype.getRgbText = function() {
    return ("#" + this.getHexCode(this.pRgb));
  }

  /**********************************************************************************************
   * Return the RYB color in #RRYYBB format.
   *
   * @returns The RYB color in #RRYYBB.
   */
  RgbRyb.prototype.getRybText = function() {
    return ("#" + this.getHexCode(this.pRyb));
  }

  /**********************************************************************************************
   * Returns the red component of the RGB value.
   *
   * @return  The red color 0 - 255.
   */
  RgbRyb.prototype.getRgbRed = function() {
    return (this.pRgb[0]);
  }

  /**********************************************************************************************
   * Returns the green component of the RGB value.
   *
   * @return  The green color 0 - 255.
   */
  RgbRyb.prototype.getRgbGreen = function() {
    return (this.pRgb[1]);
  }

  /**********************************************************************************************
   * Returns the blue component of the RGB value.
   *
   * @return  The blue color 0 - 255.
   */
  RgbRyb.prototype.getRgbBlue = function() {
    return (this.pRgb[2]);
  }

  /**********************************************************************************************
   * Returns the red component of the RYB value.
   *
   * @return  The red color 0 - 255.
   */
  RgbRyb.prototype.getRybRed = function() {
    return (this.pRyb[0]);
  }

  /**********************************************************************************************
   * Returns the yellow component of the RYB value.
   *
   * @return  The yellow color 0 - 255.
   */
  RgbRyb.prototype.getRybYellow = function() {
    return (this.pRyb[1]);
  }

  /**********************************************************************************************
   * Returns the blue component of the RYB value.
   *
   * @return  The blue color 0 - 255.
   */
  RgbRyb.prototype.getRybBlue = function() {
    return (this.pRyb[2]);
  }
  this.init = function() {
    // method body
  }();
}

function hex2rgb(hex) {
  if (hex[0] == "#") {
    hex = hex.slice(1, hex.length);
  }
  let r = parseInt(hex.slice(0, 2), 16);
  let g = parseInt(hex.slice(2, 4), 16);
  let b = parseInt(hex.slice(4, 6), 16);
  return "rgb("+r+", "+g+", "+b+")";
}

let MAX_RGB_SUM = 384;
function chs2ryb(c, h, s) {
  c = c * MAX_RGB_SUM;
  h = h * MAX_RGB_SUM;
  s = s * MAX_RGB_SUM;
  let max = Math.max(c, h, s);
  if (max > 255) {
    let ratio = 255/max;
    c = c * ratio;
    h = h * ratio;
    s = s * ratio;
  }
  return [c, h, s];
}

// rgb_ryb();
// var color = new RgbRyb();
// color.setRyb(128, 128, 128);
// console.log(hex2rgb(color.getRgbText()));
// color.setRyb(255, 128, 128);
// console.log(hex2rgb(color.getRgbText()));
// color.setRyb(128, 255, 128);
// console.log(hex2rgb(color.getRgbText()));
// color.setRyb(128, 128, 255);
// console.log(hex2rgb(color.getRgbText()));
// color.setRyb(0, 255, 0);
// console.log(hex2rgb(color.getRgbText()));
// color.setRyb(127, 255, 0);
// console.log(hex2rgb(color.getRgbText()));
// color.setRyb(0, 255, 0);
// console.log(hex2rgb(color.getRgbText()));
// color.setRyb(0, 255, 127);
// console.log(hex2rgb(color.getRgbText()));
// color.setRyb(0, 255, 255);
// console.log(hex2rgb(color.getRgbText()));
// color.setRyb(0, 127, 255);
// console.log(hex2rgb(color.getRgbText()));
// color.setRyb(0, 0, 255);
// console.log(hex2rgb(color.getRgbText()));
// color.setRyb(127, 0, 255);
// console.log(hex2rgb(color.getRgbText()));
// color.setRyb(255, 0, 255);
// console.log(hex2rgb(color.getRgbText()));

// for (var i = 0; i < 12; i++) {
//   console.log(i*(1/11));
// }