// @name      The Fade Anything Technique
// @namespace http://www.axentric.com/aside/fat/
// @version   1.0-RC1
// @author    Adam Michela

/* 
  Utility Functions: added by John Bentley
*/

/*
   IE5 fix for lack of wildcard support in 
    getElementsByTagName("*")
    
    Source: http://www.siteexperts.com/tips/contents/ts16/page3.asp

function ie_getElementsByTagName(str) {
 alert("in ie5 fix")
 // Map to the all collections
 if (str=="*")
  return document.all
 else
  return document.all.tags(str)
 
}

if (document.all)
 document.getElementsByTagName = ie_getElementsByTagName
 */ 

/* Usage From: http://www.axentric.com/posts/default/7 */
/* 
How to use: Simple
Include the FAT script in your page like so:

<script type="text/javascript" src="http://www.axentric.com/aside/fat/fat.js"></script>

Choose the element, such as a paragraph, you would like to spotlight and
 give it a class of "fade":

<p id="paragraph1" class="fade">Watch me fade</p>

Voila! You're done. The paragraph will fade from the default color of 
yellow (#FFFF33) to whatever it's native background color is. */

/* 
How to use: Advanced

Change the default fade from color:

<p id="paragraph1" class="fade-0066FF">Watch me fade from Blue (#0066FF)</p>

Fade an element after the page load from a script (such as after an Ajax transaction):

Fat.fade_element("paragraph1")

The Fat.fade_element() function accepts several arguments: 
Target ID, Frames Per Second, Fade Duration, Fade Color, Final Color.

For example, if you wanted to fade paragraph1 from red to green at 60 frames per second 
for 10 seconds:

Fat.fade_element("paragraph1", 60, 10000, "#FF0000", "#00CC00")

Please note, the ID of the element is a required argument. 
As such all elements that you wish to fade (even by class) must have some unique ID. 
The ID can be anything. */

var Fat = {
	make_hex : function (r,g,b) 
	{
		r = r.toString(16); if (r.length == 1) r = '0' + r;
		g = g.toString(16); if (g.length == 1) g = '0' + g;
		b = b.toString(16); if (b.length == 1) b = '0' + b;
		return "#" + r + g + b;
	},
	fade_all : function ()
	{
		var a = document.getElementsByTagName("*");
		for (var i = 0; i < a.length; i++) 
		{
			var o = a[i];
			var r = /fade-?(\w{3,6})?/.exec(o.className);
			if (r)
			{
				if (!r[1]) r[1] = "";
				if (o.id) Fat.fade_element(o.id,null,null,"#"+r[1]);
			}
		}
	},
	fade_element : function (id, fps, duration, from, to) 
	{
		if (!fps) fps = 30;
		if (!duration) duration = 1000;
		if (!from || from=="#") from = "#FFFF33";
		if (!to) to = this.get_bgcolor(id);
		
		var frames = Math.round(fps * (duration / 1000));
		var interval = duration / frames;
		var delay = interval;
		var frame = 0;
		
		if (from.length < 7) from += from.substr(1,3);
		if (to.length < 7) to += to.substr(1,3);
		
		var rf = parseInt(from.substr(1,2),16);
		var gf = parseInt(from.substr(3,2),16);
		var bf = parseInt(from.substr(5,2),16);
		var rt = parseInt(to.substr(1,2),16);
		var gt = parseInt(to.substr(3,2),16);
		var bt = parseInt(to.substr(5,2),16);
		
		var r,g,b,h;
		while (frame < frames)
		{
			r = Math.floor(rf * ((frames-frame)/frames) + rt * (frame/frames));
			g = Math.floor(gf * ((frames-frame)/frames) + gt * (frame/frames));
			b = Math.floor(bf * ((frames-frame)/frames) + bt * (frame/frames));
			h = this.make_hex(r,g,b);
		
			setTimeout("Fat.set_bgcolor('"+id+"','"+h+"')", delay);

			frame++;
			delay = interval * frame; 
		}
		setTimeout("Fat.set_bgcolor('"+id+"','"+to+"')", delay);
	},
	set_bgcolor : function (id, c)
	{
		var o = document.getElementById(id);
		// Jlb: Added a safety check to prevent error in IE when Fat called asynchronously.
		// But a flicker may result.
		if(o) o.style.backgroundColor = c;
	},	
	get_bgcolor : function (id)
	{
		var o = document.getElementById(id);
		while(o)
		{
			var c;
			if (window.getComputedStyle) c = window.getComputedStyle(o,null).getPropertyValue("background-color");
			if (o.currentStyle) c = o.currentStyle.backgroundColor;
			if ((c != "" && c != "transparent") || o.tagName == "BODY") { break; }
			o = o.parentNode;
		}
		if (c == undefined || c == "" || c == "transparent") c = "#FFFFFF";
		var rgb = c.match(/rgb\s*\(\s*(\d{1,3})\s*,\s*(\d{1,3})\s*,\s*(\d{1,3})\s*\)/);
		if (rgb) c = this.make_hex(parseInt(rgb[1]),parseInt(rgb[2]),parseInt(rgb[3]));
		return c;
	}
}

addLoadEvent(function (){
	Fat.fade_all();
});
	
/* Utility */

/*
Summary:  adds a function to the onload event without overwriting
          previous functions assignments to onload.
Usage Examples: 
          addLoadEvent(nameOfSomeFunctionToRunOnPageLoad);
          // Or
          addLoadEvent(function() {
            // more code to run on page load 
          });
Source:  Simon Willson > Executing JavaScript on page load  
        http://simon.incutio.com/archive/2004/05/26/addLoadEvent */
function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      oldonload();
      func();
    }
  }
}