/* =================================================================================================
 * TransMenu 
 * March, 2003
 *
 * Customizable multi-level animated DHTML menus with transparency.
 *
 * Copyright 2003-2004, Aaron Boodman (www.youngpup.net)
 * =================================================================================================
 * "Can I use this?"
 * 
 * Use of this library is governed by the Creative Commons Attribution 2.0 License. You can check it 
 * out at: http://creativecommons.org/licenses/by/2.0/
 *
 * Basically: You may copy, distribute, and eat this code as you wish. But you must give me credit 
 * for writing it. You may not misrepresent yourself as the author of this code.
 * =================================================================================================
 * "It's kinda hard to read, though"
 *
 * The uncompressed, commented version of this script can be found at: 
 * http://youngpup.net/projects/transMenus
 * =================================================================================================
 * updates:
 * 04.19.04 fixed cascade problem with menus nested greater than two levels.
 * 12.23.03 added hideCurrent for menu actuators with no menus. renamed to TransMenu.
 * 04.18.03	fixed render bug in IE 5.0 Mac by removing that browser from compatibility table ;)
 *			also made gecko check a little more strict by specifying build no.
 * ============================================================================================== */



//==================================================================================================
// Configuration properties
//==================================================================================================
TransMenu.spacerGif = "/img/spacer.gif";                     // path to a transparent spacer gif
TransMenu.dingbatOn = "/siteSpecific/page/images/submenu-on2.gif";            // path to the active sub menu dingbat
TransMenu.dingbatOff = "/siteSpecific/page/images/submenu-off2.gif";          // path to the inactive sub menu dingbat
TransMenu.dingbatSize = 14;                            // size of the dingbat (square shape assumed)
TransMenu.menuPadding = 5;                             // padding between menu border and items grid
TransMenu.itemPadding = 3;                             // additional padding around each item
TransMenu.shadowSize = 2;                              // size of shadow under menu
TransMenu.shadowOffset = 3;                            // distance shadow should be offset from leading edge
TransMenu.shadowColor = "#888";                       // color of shadow (transparency is set in CSS)
TransMenu.shadowPng = "/siteSpecific/page/images/grey-40.png";               // a PNG graphic to serve as the shadow for mac IE5
TransMenu.backgroundColor = "#DAE6DD";                   // color of the background (transparency set in CSS)
TransMenu.backgroundPng = "/siteSpecific/page/images/grey-90.png";          // a PNG graphic to server as the background for mac IE5
TransMenu.hideDelay = 800;                            // number of milliseconds to wait before hiding a menu
TransMenu.slideTime = 400;                             // number of milliseconds it takes to open and close a menu


//==================================================================================================
// Internal use properties
//==================================================================================================
TransMenu.reference = {topLeft:1,topRight:2,bottomLeft:3,bottomRight:4};
TransMenu.direction = {down:1,right:2};
TransMenu.registry = [];
TransMenu._maxZ = 100;



//==================================================================================================
// Static methods
//==================================================================================================
// supporting win ie5+, mac ie5.1+ and gecko >= mozilla 1.0
TransMenu.isSupported = function() {
  var ua = navigator.userAgent.toLowerCase();
  var pf = navigator.platform.toLowerCase();
  var an = navigator.appName;
  var r = false;

  if (ua.indexOf("gecko") > -1 && navigator.productSub >= 20020605) r = true; // gecko >= moz 1.0
  else if (an == "Microsoft Internet Explorer") {
          if (document.getElementById) { // ie5.1+ mac,win
                  if (pf.indexOf("mac") == 0) {
        r = /msie (\d(.\d*)?)/.test(ua) && Number(RegExp.$1) >= 5.1;
      }
      else r = true;
          }
  }

  return r;
}

// call this in onload once menus have been created
TransMenu.initialize = function() {
    for (var i = 0, menu = null; menu = this.registry[i]; i++) {
            menu.initialize();
    }
}

// call this in document body to write out menu html
TransMenu.renderAll = function() {
    var aMenuHtml = [];


    for (var i = 0, menu = null; menu = this.registry[i]; i++) {
            aMenuHtml[i] = menu.toString();
    }


    document.write(aMenuHtml.join(""));

/*
    for (var i = 0, menu = null; menu = this.registry[i]; i++) {

      var curId = menu.getId();
      alert(curId);
      var blah = document.getElementById(curId);
      var iframeEl = document.createElement("IFRAME");


      blah.id = 'old' + curId;
      iframeEl.id = curId;

      iframeEl.frameBorder = 1;
      iframeEl.src = "javascript:;";

      //iframeEl.style.width = "100px";
      //iframeEl.style.height = "100px";
      //iframeEl.style.border = "1px solid blue";
      iframeEl.style.display = "none";

      iframeEl.style.position = "absolute";
      iframeEl.style.filter = "progid:DXImageTransform.Microsoft.Alpha(style=0,opacity=0)";

      blah.iframeEl = blah.parentNode.insertBefore(iframeEl, blah);
    }
*/
}

function showSelects() {

  if (document.all) {
    var selNodes = document.getElementsByTagName('select')
    var i = 0;
    if (!selNodes.item(0)){ 
    
    } else {
      do {
          
        if (selNodes.item(i).style.zIndex != -1)
          selNodes.item(i).style.visibility = 'visible';

      } while(++i < selNodes.length);

    }
  }
}

function hideSelects() {

  if (document.all) {
    var selNodes = document.getElementsByTagName('select')
    var i = 0;
    if (!selNodes.item(0)){
    
    } else {

      do {

        selNodes.item(i).style.visibility = 'hidden';

      } while(++i < selNodes.length);

    }
  }
}



//==================================================================================================
// TransMenu constructor (only called internally)
//==================================================================================================
// oActuator            : The thing that causes the menu to be shown when it is mousedover. Either a
//                        reference to an HTML element, or a TransMenuItem from an existing menu.
// iDirection           : The direction to slide out. One of TransMenu.direction.
// iLeft                : Left pixel offset of menu from actuator
// iTop                 : Top pixel offset of menu from actuator
// iReferencePoint      : Corner of actuator to measure from. One of TransMenu.referencePoint.
// parentMenuSet        : Menuset this menu will be added to.
//==================================================================================================
function TransMenu(oActuator, iDirection, iLeft, iTop, iReferencePoint, parentMenuSet) {
        // public methods
        this.addItem = addItem;
        this.addMenu = addMenu;
        this.toString = toString;
        this.getId = getId;
        this.initialize = initialize;
        this.isOpen = false;
        this.show = show;
        this.hide = hide;
        this.items = [];

        // events
        this.onactivate = new Function();       // when the menu starts to slide open
        this.ondeactivate = new Function();     // when the menu finishes sliding closed
        this.onmouseover = new Function();      // when the menu has been moused over
        this.onqueue = new Function();          // hack .. when the menu sets a timer to be closed a little while in the future
		    this.ondequeue = new Function();

        // initialization
        this.index = TransMenu.registry.length;
        TransMenu.registry[this.index] = this;

        var id = "TransMenu" + this.index;
        var contentHeight = null;
        var contentWidth = null;
        var childMenuSet = null;
        var animating = false;
        var childMenus = [];
        var slideAccel = -1;
        var elmCache = null;
        var ready = false;
        var _this = this;
        var a = null;


        var pos = iDirection == TransMenu.direction.down ? "top" : "left";
        var dim = null;

        function getId() {
          return id;
        }


        // private and public method implimentations
        function addItem(sText, sUrl) {
                var item = new TransMenuItem(sText, sUrl, this);
                item._index = this.items.length;
                this.items[item._index] = item;
        }

        function addMenu(oMenuItem) {
          if (!oMenuItem.parentMenu == this)
            throw new Error("Cannot add a menu here");

          if (childMenuSet == null)
            childMenuSet = new TransMenuSet(TransMenu.direction.right, -5, 2, TransMenu.reference.topRight);

          var m = childMenuSet.addMenu(oMenuItem);

          childMenus[oMenuItem._index] = m;
          m.onmouseover = child_mouseover;
          m.ondeactivate = child_deactivate;
          m.onqueue = child_queue;
				  m.ondequeue = child_dequeue;

          return m;
        }

        function initialize() {
          initCache();
          initEvents();
          initSize();
          ready = true;
        }

        function show() {
          //dbg_dump("show");
          if (ready) {
            _this.isOpen = true;
            animating = true;

            setContainerPos();
            elmCache["clip"].style.visibility = "visible";
            elmCache["clip"].style.zIndex = TransMenu._maxZ++;
            //dbg_dump("maxZ: " + TransMenu._maxZ);

            //hideSelects();
            slideStart();

            _this.onactivate();
          }
        }

        function hide() {
          if (ready) {
            _this.isOpen = false;
            animating = true;

            for (var i = 0, item = null; item = elmCache.item[i]; i++) 
              dehighlight(item);

            if (childMenuSet)
              childMenuSet.hide();

            slideStart();

            _this.ondeactivate();
          }
        }

        function setContainerPos() {
          var sub = oActuator.constructor == TransMenuItem; 
          var act = sub ? oActuator.parentMenu.elmCache["item"][oActuator._index] : oActuator; 
          var el = act;
          
          var x = 0;
          var y = 0;
				/*
				var minX = 0;
				var maxX = (window.innerWidth ? window.innerWidth + window.scrollX : document.body.clientWidth + document.body.scrollLeft) - parseInt(elmCache["clip"].style.width);
				var minY = 0;
				var maxY = (window.innerHeight ? window.innerHeight + window.scrollY : document.body.clientHeight + document.body.scrollTop) - parseInt(elmCache["clip"].style.height);
                */

          var minX = 0;
          var maxX = (window.innerWidth ? window.innerWidth : document.body.clientWidth) - parseInt(elmCache["clip"].style.width);
          var minY = 0;
          var maxY = (window.innerHeight ? window.innerHeight : document.body.clientHeight) - parseInt(elmCache["clip"].style.height);

          // add up all offsets... subtract any scroll offset
          while (sub ? el.parentNode.className.indexOf("transMenu") == -1 : el.offsetParent) {
                  x += el.offsetLeft;
                  y += el.offsetTop;

                  if (el.scrollLeft) x -= el.scrollLeft;
                  if (el.scrollTop) y -= el.scrollTop;
                  
                  el = el.offsetParent;
          }

          if (oActuator.constructor == TransMenuItem) {
                  x += parseInt(el.parentNode.style.left);
                  y += parseInt(el.parentNode.style.top);
          }

          switch (iReferencePoint) {
                  case TransMenu.reference.topLeft:
                          break;
                  case TransMenu.reference.topRight:
                          x += act.offsetWidth;
                          break;
                  case TransMenu.reference.bottomLeft:
                          y += act.offsetHeight;
                          break;
                  case TransMenu.reference.bottomRight:
                          x += act.offsetWidth;
                          y += act.offsetHeight;
                          break;
          }

          x += iLeft;
          y += iTop;

          x = Math.max(Math.min(x, maxX), minX);
          y = Math.max(Math.min(y, maxY), minY);

          elmCache["clip"].style.left = x + "px";
          elmCache["clip"].style.top = y + "px";
        }

        function slideStart() {
          var x0 = parseInt(elmCache["content"].style[pos]);
          var x1 = _this.isOpen ? 0 : -dim;

          if (a != null) a.stop();
          a = new Accelimation(x0, x1, TransMenu.slideTime, slideAccel);

          a.onframe = slideFrame;
          a.onend = slideEnd;

          a.start();
        }

        function slideFrame(x) {
                elmCache["content"].style[pos] = x + "px";
        }

        function slideEnd() {
                if (!_this.isOpen) elmCache["clip"].style.visibility = "hidden";
                animating = false;
        }

        function initSize() {
          // everything is based off the size of the items table...
          var ow = elmCache["items"].offsetWidth;
          var oh = elmCache["items"].offsetHeight;
          var ua = navigator.userAgent.toLowerCase();

          // clipping container should be ow/oh + the size of the shadow
          elmCache["clip"].style.width = ow + TransMenu.shadowSize +  2 + "px";
          elmCache["clip"].style.height = oh + TransMenu.shadowSize + 2 + "px";

          // same with content...
          elmCache["content"].style.width = ow + TransMenu.shadowSize + "px";
          elmCache["content"].style.height = oh + TransMenu.shadowSize + "px";

          contentHeight = oh + TransMenu.shadowSize;
          contentWidth = ow + TransMenu.shadowSize;
          
          dim = iDirection == TransMenu.direction.down ? contentHeight : contentWidth;

          // set initially closed
          elmCache["content"].style[pos] = -dim - TransMenu.shadowSize + "px";
          elmCache["clip"].style.visibility = "hidden";

          // if *not* mac/ie 5
          if (ua.indexOf("mac") == -1 || ua.indexOf("gecko") > -1) {
            // set background div to offset size
            elmCache["background"].style.width = ow + "px";
            elmCache["background"].style.height = oh + "px";
            elmCache["background"].style.backgroundColor = TransMenu.backgroundColor;

            // shadow left starts at offset left and is offsetHeight pixels high
            elmCache["shadowRight"].style.left = ow + "px";
            elmCache["shadowRight"].style.height = oh - (TransMenu.shadowOffset - TransMenu.shadowSize) + "px";
            elmCache["shadowRight"].style.backgroundColor = TransMenu.shadowColor;

            // shadow bottom starts at offset height and is offsetWidth - shadowOffset 
            // pixels wide (we don't want the bottom and right shadows to overlap or we 
            // get an extra bright bottom-right corner)
            elmCache["shadowBottom"].style.top = oh + "px";
            elmCache["shadowBottom"].style.width = ow - TransMenu.shadowOffset + "px";
            elmCache["shadowBottom"].style.backgroundColor = TransMenu.shadowColor;
          }
          // mac ie is a little different because we use a PNG for the transparency
          else {
            // set background div to offset size
            elmCache["background"].firstChild.src = TransMenu.backgroundPng;
            elmCache["background"].firstChild.width = ow;
            elmCache["background"].firstChild.height = oh;

            // shadow left starts at offset left and is offsetHeight pixels high
            elmCache["shadowRight"].firstChild.src = TransMenu.shadowPng;
            elmCache["shadowRight"].style.left = ow + "px";
            elmCache["shadowRight"].firstChild.width = TransMenu.shadowSize;
            elmCache["shadowRight"].firstChild.height = oh - (TransMenu.shadowOffset - TransMenu.shadowSize);

            // shadow bottom starts at offset height and is offsetWidth - shadowOffset 
            // pixels wide (we don't want the bottom and right shadows to overlap or we 
            // get an extra bright bottom-right corner)
            elmCache["shadowBottom"].firstChild.src = TransMenu.shadowPng;
            elmCache["shadowBottom"].style.top = oh + "px";
            elmCache["shadowBottom"].firstChild.height = TransMenu.shadowSize;
            elmCache["shadowBottom"].firstChild.width = ow - TransMenu.shadowOffset;
          }
        }
        
        function initCache() {
          var menu = document.getElementById(id);
          var all = menu.all ? menu.all : menu.getElementsByTagName("*"); // IE/win doesn't support * syntax, but does have the document.all thing

          elmCache = {};
          elmCache["clip"] = menu;
          elmCache["item"] = [];
          
          for (var i = 0, elm = null; elm = all[i]; i++) {
            switch (elm.className) {
              case "items":
              case "content":
              case "background":
              case "shadowRight":
              case "shadowBottom":
                      elmCache[elm.className] = elm;
                      break;
              case "item":
                      elm._index = elmCache["item"].length;
                      elmCache["item"][elm._index] = elm;
                      break;
            }
          }

          // hack!
          _this.elmCache = elmCache;
        }

        function initEvents() {
          // hook item mouseover
          for (var i = 0, item = null; item = elmCache.item[i]; i++) {
                  item.onmouseover = item_mouseover;
                  item.onmouseout = item_mouseout;
                  item.onclick = item_click;
          }

          // hook actuation
          if (typeof oActuator.tagName != "undefined") {
                  oActuator.onmouseover = actuator_mouseover;
                  oActuator.onmouseout = actuator_mouseout;
          }

          // hook menu mouseover
          elmCache["content"].onmouseover = content_mouseover;
          elmCache["content"].onmouseout = content_mouseout;
        }

        function highlight(oRow) {
          oRow.className = "item hover";
          if (childMenus[oRow._index]) 
                  oRow.lastChild.firstChild.src = TransMenu.dingbatOn;
        }

        function dehighlight(oRow) {
          oRow.className = "item";
          if (childMenus[oRow._index]) 
                  oRow.lastChild.firstChild.src = TransMenu.dingbatOff;
        }

        function item_mouseover() {
          if (!animating) {
            highlight(this);

            if (childMenus[this._index]) 
              childMenuSet.showMenu(childMenus[this._index]);
            else if (childMenuSet)
              childMenuSet.hide(0, true);
          }
        }

        function item_mouseout() {
          if (!animating) {
            if (childMenus[this._index])
              childMenuSet.hideMenu(childMenus[this._index]);
            else    // otherwise child_deactivate will do this
              dehighlight(this);
          }
        }

        function item_click() {
          if (!animating) {
            if (_this.items[this._index].url) 
                    location.href = _this.items[this._index].url;
          }
        }

        function actuator_mouseover() {
          parentMenuSet.showMenu(_this);
        }

        function actuator_mouseout() {
          parentMenuSet.hideMenu(_this);
        }

        function content_mouseover() {
          if (!animating) {
            parentMenuSet.showMenu(_this);
            _this.onmouseover();
          }
        }

        function content_mouseout() {
          if (!animating) {
            parentMenuSet.hideMenu(_this);
          }
        }

        function child_mouseover() {
          if (!animating) {
            parentMenuSet.showMenu(_this);
          }
        }

        function child_deactivate() {
          for (var i = 0; i < childMenus.length; i++) {
            if (childMenus[i] == this) {
              dehighlight(elmCache["item"][i]);
              break;
            }
          }
        }

        function child_queue() {
          parentMenuSet.hideMenu(_this);
        }

        function child_dequeue() {
          parentMenuSet.showMenu(_this);
        }



        function toString() {
          var aHtml = [];
          var sClassName = "transMenu" + (oActuator.constructor != TransMenuItem ? " top" : "");

          for (var i = 0, item = null; item = this.items[i]; i++) {
            aHtml[i] = item.toString(childMenus[i]);
          }




          return '<div id="' + id + '" class="' + sClassName + '">' + 
                  '<div class="content">'+
                  '<table class="items" cellpadding="0" cellspacing="0" border="0">' + 
                  '<tr style=" font-size: 0; height:' + TransMenu.menuPadding + 'px;"><td style="font-size: 0;" colspan="2" ><img src="' + TransMenu.spacerGif + '" width="1" height="' + TransMenu.menuPadding + '" /></td></tr>' + 
                  aHtml.join('') + 
                  '<tr style=" font-size: 0; height:' + TransMenu.menuPadding + 'px;"><td style="font-size: 0;" colspan="2" ><img src="' + TransMenu.spacerGif + '" width="1" height="' + TransMenu.menuPadding + '" /></td></tr></table>' + 
                  '<div class="shadowBottom"><img src="' + TransMenu.spacerGif + '" width="1" height="1"></div>' + 
                  '<div class="shadowRight"><img src="' + TransMenu.spacerGif + '" width="1" height="1"></div>' + 
                  '<div class="background"><img src="' + TransMenu.spacerGif + '" width="1" height="1"></div>' + 
            '</div></div>'; 
        }
}


//==================================================================================================
// TransMenuSet
//==================================================================================================
// iDirection           : The direction to slide out. One of TransMenu.direction.
// iLeft                : Left pixel offset of menus from actuator
// iTop                 : Top pixel offset of menus from actuator
// iReferencePoint      : Corner of actuator to measure from. One of TransMenu.referencePoint.
//==================================================================================================
TransMenuSet.registry = [];

function TransMenuSet(iDirection, iLeft, iTop, iReferencePoint) {
  // public methods
  this.addMenu = addMenu;
  this.showMenu = showMenu;
  this.hideMenu = hideMenu;
  this.hide = hide;
  this.hideCurrent = hideCurrent;

  // initialization
  var menus = [];
  var _this = this;
  var current = null;

  this.index = TransMenuSet.registry.length;
  TransMenuSet.registry[this.index] = this;

  // method implimentations...
  function addMenu(oActuator) {
    var m = new TransMenu(oActuator, iDirection, iLeft, iTop, iReferencePoint, this);
    menus[menus.length] = m;
    return m;
  }

  function showMenu(oMenu) {
    if (oMenu != current) {
        // close currently open menu
        if (current != null) {
          hide(current, true);
        } else {
          hideSelects();
        }

        // set current menu to this one
        current = oMenu;

        // if this menu is closed, open it
        oMenu.show();
    }
    else {
        // hide pending calls to close this menu
        cancelHide(oMenu);
    }
  }

  function hideMenu(oMenu) {
    //dbg_dump("hideMenu a " + oMenu.index);
    if (current == oMenu && oMenu.isOpen) {

      //dbg_dump("hideMenu b " + oMenu.index);
      if (!oMenu.hideTimer)
        scheduleHide(oMenu);

    }
  }

  function scheduleHide(oMenu) {
    //dbg_dump("scheduleHide " + oMenu.index);
    oMenu.onqueue();
    oMenu.hideTimer = window.setTimeout("TransMenuSet.registry[" + _this.index + "].hide(TransMenu.registry[" + oMenu.index + "], false);", TransMenu.hideDelay);
  }

  function cancelHide(oMenu) {
    //dbg_dump("cancelHide " + oMenu.index);
    if (oMenu.hideTimer) {
      oMenu.ondequeue();
      window.clearTimeout(oMenu.hideTimer);
      oMenu.hideTimer = null;
    }
  }

  function hide(oMenu, posponeHideSelectors) {
    posponeHideSelectors = posponeHideSelectors || 0;

    if (!oMenu && current) {
      oMenu = current;
    }

    if (oMenu && current == oMenu && oMenu.isOpen) {
      hideCurrent();

      if (!posponeHideSelectors) {
        showSelects();
      }
    }
  }

  function hideCurrent() {
    if (null != current) {
      cancelHide(current);
      current.hideTimer = null;
      current.hide();
      current = null;
    }
  }
}

//==================================================================================================
// TransMenuItem (internal)
// represents an item in a dropdown
//==================================================================================================
// sText        : The item display text
// sUrl         : URL to load when the item is clicked
// oParent      : Menu this item is a part of
//==================================================================================================
function TransMenuItem(sText, sUrl, oParent) {
        this.toString = toString;
        this.text = sText;
        this.url = sUrl;
        this.parentMenu = oParent;

        function toString(bDingbat) {
                var sDingbat = bDingbat ? TransMenu.dingbatOff : TransMenu.spacerGif;
                var iEdgePadding = TransMenu.itemPadding + TransMenu.menuPadding;
                var sPaddingLeft = "padding:" + TransMenu.itemPadding + "px; padding-left:" + iEdgePadding + "px;"
                var sPaddingRight = "padding:" + TransMenu.itemPadding + "px; padding-right:" + iEdgePadding + "px;"

                return '<tr class="item"><td nowrap style="' + sPaddingLeft + '">' + 
                        sText + '</td><td width="14" style="' + sPaddingRight + '">' + 
                        '<img src="' + sDingbat + '" width="14" height="14"></td></tr>';
        }
}






//=====================================================================
// Accel[erated] [an]imation object
// change a property of an object over time in an accelerated fashion
//=====================================================================
// obj  : reference to the object whose property you'd like to animate
// prop : property you would like to change eg: "left"
// to   : final value of prop
// time : time the animation should take to run
// zip	: optional. specify the zippiness of the acceleration. pick a 
//		  number between -1 and 1 where -1 is full decelerated, 1 is 
//		  full accelerated, and 0 is linear (no acceleration). default
//		  is 0.
// unit	: optional. specify the units for use with prop. default is 
//		  "px".
//=====================================================================
// bezier functions lifted from the lib_animation.js file in the 
// 13th Parallel API. www.13thparallel.org
//=====================================================================

function Accelimation(from, to, time, zip) {
	if (typeof zip  == "undefined") zip  = 0;
	if (typeof unit == "undefined") unit = "px";

        this.x0         = from;
        this.x1		= to;
	this.dt		= time;
	this.zip	= -zip;
	this.unit	= unit;
	this.timer	= null;
	this.onend	= new Function();
        this.onframe    = new Function();
}



//=====================================================================
// public methods
//=====================================================================

// after you create an accelimation, you call this to start it-a runnin'
Accelimation.prototype.start = function() {
	this.t0 = new Date().getTime();
	this.t1 = this.t0 + this.dt;
	var dx	= this.x1 - this.x0;
	this.c1 = this.x0 + ((1 + this.zip) * dx / 3);
	this.c2 = this.x0 + ((2 + this.zip) * dx / 3);
	Accelimation._add(this);
}

// and if you need to stop it early for some reason...
Accelimation.prototype.stop = function() {
	Accelimation._remove(this);
}



//=====================================================================
// private methods
//=====================================================================

// paints one frame. gets called by Accelimation._paintAll.
Accelimation.prototype._paint = function(time) {
	if (time < this.t1) {
		var elapsed = time - this.t0;
	        this.onframe(Accelimation._getBezier(elapsed/this.dt,this.x0,this.x1,this.c1,this.c2));
        }
	else this._end();
}

// ends the animation
Accelimation.prototype._end = function() {
	Accelimation._remove(this);
        this.onframe(this.x1);
	this.onend();
}




//=====================================================================
// static methods (all private)
//=====================================================================

// add a function to the list of ones to call periodically
Accelimation._add = function(o) {
	var index = this.instances.length;
	this.instances[index] = o;
	// if this is the first one, start the engine
	if (this.instances.length == 1) {
		this.timerID = window.setInterval("Accelimation._paintAll()", this.targetRes);
	}
}

// remove a function from the list
Accelimation._remove = function(o) {
	for (var i = 0; i < this.instances.length; i++) {
		if (o == this.instances[i]) {
			this.instances = this.instances.slice(0,i).concat( this.instances.slice(i+1) );
			break;
		}
	}
	// if that was the last one, stop the engine
	if (this.instances.length == 0) {
		window.clearInterval(this.timerID);
		this.timerID = null;
	}
}

// "engine" - call each function in the list every so often
Accelimation._paintAll = function() {
	var now = new Date().getTime();
	for (var i = 0; i < this.instances.length; i++) {
		this.instances[i]._paint(now);
	}
}


// Bezier functions:
Accelimation._B1 = function(t) { return t*t*t }
Accelimation._B2 = function(t) { return 3*t*t*(1-t) }
Accelimation._B3 = function(t) { return 3*t*(1-t)*(1-t) }
Accelimation._B4 = function(t) { return (1-t)*(1-t)*(1-t) }


//Finds the coordinates of a point at a certain stage through a bezier curve
Accelimation._getBezier = function(percent,startPos,endPos,control1,control2) {
	return endPos * this._B1(percent) + control2 * this._B2(percent) + control1 * this._B3(percent) + startPos * this._B4(percent);
}


//=====================================================================
// static properties
//=====================================================================

Accelimation.instances = [];
Accelimation.targetRes = 10;
Accelimation.timerID = null;


//=====================================================================
// IE win memory cleanup
//=====================================================================

if (window.attachEvent) {
	var cearElementProps = [
		'data',
		'onmouseover',
		'onmouseout',
		'onmousedown',
		'onmouseup',
		'ondblclick',
		'onclick',
		'onselectstart',
		'oncontextmenu'
	];

	window.attachEvent("onunload", function() {
        var el;
        for(var d = document.all.length;d--;){
            el = document.all[d];
            for(var c = cearElementProps.length;c--;){
                el[cearElementProps[c]] = null;
            }
        }
	});
}