/*
  VERSION: Drop Shadow jQuery Plugin 1.6  12-13-2007

  REQUIRES: jquery.js (verified for 1.3.2)

  SYNTAX: $(selector).dropShadow(options);  // Creates new drop shadows
          $(selector).redrawShadow();       // Redraws shadows on elements
          $(selector).removeShadow();       // Removes shadows from elements
          $(selector).shadowId();           // Returns an existing shadow's ID

  OPTIONS:

    left    : integer (default = 4)
    top     : integer (default = 4)
    blur    : integer (default = 2)
    opacity : decimal (default = 0.5)
    color   : string (default = "black")
    swap    : boolean (default = false)

  $("#banner-header").dropShadow({left: 0, top: 2, opacity: 0.8, color: "#2e8dfe", blur: 0});

  AUTHOR: Larry Stevens.  This work is in the public domain,
          and is not supported in any way. Use it at your own risk.
*/


(function($){

  var dropShadowZindex = 1;  //z-index counter

  $.fn.dropShadow = function(options)
  {
    // Default options
    var opt = $.extend({
      left: 4,
      top: 4,
      blur: 2,
      opacity: .5,
      color: "black",
      swap: false
      }, options);
    var jShadows = $([]);  //empty jQuery collection
    
    // Loop through original elements
    this.not(".dropShadow").each(function()
    {
      var jthis = $(this);
      var shadows = [];
      var blur = (opt.blur <= 0) ? 0 : opt.blur;
      var opacity = (blur == 0) ? opt.opacity : opt.opacity / (blur * 8);
      var zOriginal = (opt.swap) ? dropShadowZindex : dropShadowZindex + 1;
      var zShadow = (opt.swap) ? dropShadowZindex + 1 : dropShadowZindex;
      
      // Create ID for shadow
      var shadowId;
      if (this.id) {
        shadowId = this.id + "_dropShadow";
      }
      else {
        shadowId = "ds" + (1 + Math.floor(9999 * Math.random()));
      }

      // Modify original element
      $.data(this, "shadowId", shadowId); //store id in expando
      $.data(this, "shadowOptions", options); //store options in expando
      jthis
        .attr("shadowId", shadowId)
        .css("zIndex", zOriginal);
      if (jthis.css("position") != "absolute") {
        jthis.css({
          position: "relative",
          zoom: 1 //for IE layout
        });
      }

      // Create first shadow layer
      bgColor = jthis.css("backgroundColor");
      if (bgColor == "rgba(0, 0, 0, 0)") bgColor = "transparent";  //Safari
      if (bgColor != "transparent" || jthis.css("backgroundImage") != "none" 
          || this.nodeName == "SELECT" 
          || this.nodeName == "INPUT"
          || this.nodeName == "TEXTAREA") {   
        shadows[0] = $("<div></div>")
          .css("background", opt.color);                
      }
      else {
        shadows[0] = jthis
          .clone()
          .removeAttr("id")
          .removeAttr("name")
          .removeAttr("shadowId")
          .css("color", opt.color);
      }
      shadows[0]
        .addClass("dropShadow")
        .css({
          height: jthis.outerHeight(),
          left: blur,
          opacity: opacity,
          position: "absolute",
          top: blur,
          width: jthis.outerWidth(),
          zIndex: zShadow
        });
        
      // Create other shadow layers
      var layers = (8 * blur) + 1;
      for (i = 1; i < layers; i++) {
        shadows[i] = shadows[0].clone();
      }

      // Position layers
      var i = 1;      
      var j = blur;
      while (j > 0) {
        shadows[i].css({left: j * 2, top: 0});           //top
        shadows[i + 1].css({left: j * 4, top: j * 2});   //right
        shadows[i + 2].css({left: j * 2, top: j * 4});   //bottom
        shadows[i + 3].css({left: 0, top: j * 2});       //left
        shadows[i + 4].css({left: j * 3, top: j});       //top-right
        shadows[i + 5].css({left: j * 3, top: j * 3});   //bottom-right
        shadows[i + 6].css({left: j, top: j * 3});       //bottom-left
        shadows[i + 7].css({left: j, top: j});           //top-left
        i += 8;
        j--;
      }

      // Create container
      var divShadow = $("<div></div>")
        .attr("id", shadowId) 
        .addClass("dropShadow")
        .css({
          left: jthis.position().left + opt.left - blur,
          marginTop: jthis.css("marginTop"),
          marginRight: jthis.css("marginRight"),
          marginBottom: jthis.css("marginBottom"),
          marginLeft: jthis.css("marginLeft"),
          position: "absolute",
          top: jthis.position().top + opt.top - blur,
          zIndex: zShadow
        });

      // Add layers to container  
      for (i = 0; i < layers; i++) {
        divShadow.append(shadows[i]);
      }
      
      // Add container to DOM
      jthis.after(divShadow);

      // Add shadow to return set
      jShadows = jShadows.add(divShadow);

      // Re-align shadow on window resize
      $(window).resize(function()
      {
        try {
          divShadow.css({
            left: jthis.position().left + opt.left - blur,
            top: jthis.position().top + opt.top - blur
          });
        }
        catch(e){}
      });
      
      // Increment z-index counter
      dropShadowZindex += 2;

    });  //end each
    
    return this.pushStack(jShadows);
  };


  $.fn.redrawShadow = function()
  {
    // Remove existing shadows
    this.removeShadow();
    
    // Draw new shadows
    return this.each(function()
    {
      var shadowOptions = $.data(this, "shadowOptions");
      $(this).dropShadow(shadowOptions);
    });
  };


  $.fn.removeShadow = function()
  {
    return this.each(function()
    {
      var shadowId = $(this).shadowId();
      $("div#" + shadowId).remove();
    });
  };


  $.fn.shadowId = function()
  {
    return $.data(this[0], "shadowId");
  };


  $(function()  
  {
    // Suppress printing of shadows
    var noPrint = "<style type='text/css' media='print'>";
    noPrint += ".dropShadow{visibility:hidden;}</style>";
    $("head").append(noPrint);
  });

})(jQuery);