ColorPallet.js

Dave_js.colorPallet = function(t, n) {
  var self = this;
  
  //make sure we have valid input
  //valid types are:
  //   "rainbow", rev-rainbow" (reverse rainbow),
  //   "redblue", "rev-redblue",
  //   "blackwhite", "rev-blackwhite",
  if (
    t.indexOf("rainbow") == -1 &&
    t.indexOf("redblue") == -1 &&
    t.indexOf("blackwhite") == -1
  ) {
    t = "rainbow";
  }
  //make sure the number of colors is between 1 and 255
  if (isNaN(n) || n === "" || n <= 0) { n = 1;}
  else if (n > 255) { n = 255; }
  
  var type = t;
  var numOfColors = n;
  
  //define color object
  self.color = function(r,g,b){
    var self = this;
    var vals = {};
    
    self.toHexStr = function(){
      var self = this;
        
      function numToHex(num){
        var hexRef =[
          "0", "1", "2", "3", "4", "5", "6", "7",
          "8", "9", "A", "B", "C", "D", "E", "F"
        ];
        
        var upper = num % 16;
        var lower = parseInt(num / 16, 10);
        
        return hexRef[upper] + "" + hexRef[lower];
      }

      return "#" + numToHex(r) + numToHex(g) + numToHex(b);
    };

    self.toRgbStr = function(){
      return "rgb(" + r + "," + g + "," + b + ")";
    };
  };

  //an array of color objects
  var pallet = [];
  
  //Acessors
  self.setType = function(t){
     type = t;
  };
  self.setNumOfColors = function(n){
    numOfColors = n;
  };
  self.putPalletVal = function(r, g, b){
    pallet.push(new self.color(r, g, b));
  };
  self.getType = function(){
    return type;
  };
  self.getNumOfColors = function(){
    return numOfColors;
  };
  self.getColors = function(){
    return pallet;
  };
  self.reversePallet = function(){
    pallet = pallet.reverse();
  };
};

//calculates the pallet values
Dave_js.colorPallet.prototype.buildPallet = function(){
  var self = this;
  var num = self.getNumOfColors();
  var color_i, stepSize, midpoint;

  if (self.getType().indexOf("rainbow") != -1) {
    stepSize = Math.floor(2 * (255 / num));
    midpoint = Math.floor(num / 2);
    
    //reduce the loop by two because we manually set the last color
    num -= 1;
    
    for (color_i = 0; color_i < midpoint; color_i++) {
       self.putPalletVal(
          (255 - (color_i * stepSize)), (color_i * stepSize), 0
       );
    }
    
    for (color_i = midpoint; color_i < num; color_i++) {
       self.putPalletVal(
          0,
          (255 - ((color_i - midpoint) * stepSize)),
          ((color_i - midpoint) * stepSize)
       );
    }
    
    //get last color
    self.putPalletVal(0, 0, 255);
  } else if (self.getType().indexOf("redblue") != -1) {
    stepSize = Math.floor(255 / num);
     
    for (color_i = 0; color_i < num; color_i++) {
      self.putPalletVal((255 - (color_i * stepSize)), 0, (color_i * stepSize));
    }
  } else if (self.getType().indexOf("blackwhite") != -1) {
    stepSize = Math.floor(255 / num);
     
    for (color_i = 0; color_i < num; color_i++) {
      self.putPalletVal(
        (color_i * stepSize), (color_i * stepSize), (color_i * stepSize)
      );
    }
  }
  
  if (self.getType().indexOf("rev") != -1) {
     self.reversePallet();
  }
};

//Takes a div element as input and fills it with color boxes
//The size input determines the pixel width of the color boxes
Dave_js.colorPallet.prototype.displayColors = function(
   divEl, width, height, border
){
  var self = this;
  var pallet = self.getColors();
  var num = self.getNumOfColors();
  
  //check for a good size
  if (width === 0 || isNaN(width)) {width = 5;}
  if (height === 0 || isNaN(height)) {height = 5;}
  
  //make a valid border size
  if (isNaN(border)) {border = 0;}
  
  //make sure a valid div element was given
  if (divEl.tagName != "DIV") {return;}
  
  try{
    var tmpEl;
     
    for (var color_i = 0; color_i < num; color_i++) {
      tmpEl = document.createElement("div");
      tmpEl.style.backgroundColor = pallet[color_i].toRgbStr();
      tmpEl.style.border = "solid";
      tmpEl.style.borderWidth = border + "px";
      tmpEl.style.float = "left";
      tmpEl.style.width = width + "px";
      tmpEl.style.height = height + "px";
      
      divEl.appendChild(tmpEl);
    }
     
    tmpEl = document.createElement("div");
    tmpEl.style.float = "clear";
    divEl.appendChild(tmpEl);
  }catch(err){
     
  }
};

//Return an array of color codes in rgb or hex format
Dave_js.colorPallet.prototype.getPallet = function(f){
  var self = this;
  var pallet = self.getColors();
  var num = self.getNumOfColors();
  var out = new Array(num);
   
  for (var color_i = 0; color_i < num; color_i++) {
    if (f == "hex") {
      out[color_i] = pallet[color_i].toHexStr();
    } else {
      out[color_i] = pallet[color_i].toRgbStr();
    }
  }
   
  return out;
};