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

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 (dur)
	{
		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,dur,"#"+r[1]);
			}
		}
	},
	fade_element : function (id, fps, duration, from, to) 
	{
		if (!fps) fps = 30;
		if (!duration) duration = 3000;
		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);
		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;
	}
};
