/src/fx.js

var elemdisplay = {},
	timerId,
	fxAttrs = [
		// height animations
		[ "height", "marginTop", "marginBottom", "paddingTop", "paddingBottom" ],
		// width animations
		[ "width", "marginLeft", "marginRight", "paddingLeft", "paddingRight" ],
		// opacity animations
		[ "opacity" ]
	];

function genFx( type, num ){
	var obj = {};
	jQuery.each( fxAttrs.concat.apply([], fxAttrs.slice(0,num)), function(){
		obj[ this ] = type;
	});
	return obj;
}

jQuery.fn.extend({
	show: function(speed,callback){
		if ( speed ) {
			return this.animate( genFx("show", 3), speed, callback);
		} else {
			for ( var i = 0, l = this.length; i < l; i++ ){
				var old = jQuery.data(this[i], "olddisplay");
				
				this[i].style.display = old || "";
				
				if ( jQuery.css(this[i], "display") === "none" ) {
					var tagName = this[i].tagName, display;
					
					if ( elemdisplay[ tagName ] ) {
						display = elemdisplay[ tagName ];
					} else {
						var elem = jQuery("<" + tagName + " />").appendTo("body");
						
						display = elem.css("display");
						if ( display === "none" )
							display = "block";
						
						elem.remove();
						
						elemdisplay[ tagName ] = display;
					}
					
					jQuery.data(this[i], "olddisplay", display);
				}
			}

			// Set the display of the elements in a second loop
			// to avoid the constant reflow
			for ( var i = 0, l = this.length; i < l; i++ ){
				this[i].style.display = jQuery.data(this[i], "olddisplay") || "";
			}
			
			return this;
		}
	},

	hide: function(speed,callback){
		if ( speed ) {
			return this.animate( genFx("hide", 3), speed, callback);
		} else {
			for ( var i = 0, l = this.length; i < l; i++ ){
				var old = jQuery.data(this[i], "olddisplay");
				if ( !old && old !== "none" )
					jQuery.data(this[i], "olddisplay", jQuery.css(this[i], "display"));
			}

			// Set the display of the elements in a second loop
			// to avoid the constant reflow
			for ( var i = 0, l = this.length; i < l; i++ ){
				this[i].style.display = "none";
			}

			return this;
		}
	},

	toggleVisibility: function( fn, fn2 ){
		var bool = typeof fn === "boolean";

		return jQuery.isFunction(fn) && jQuery.isFunction(fn2) ?
			this._toggle.apply( this, arguments ) :
			fn == null || bool ?
				this.each(function(){
					var state = bool ? fn : jQuery(this).is(":hidden");
					jQuery(this)[ state ? "show" : "hide" ]();
				}) :
				this.animate(genFx("toggle", 3), fn, fn2);
	},

	fadeTo: function(speed,to,callback){
		return this.animate({opacity: to}, speed, callback);
	},

	animate: function( prop, speed, easing, callback ) {
		var optall = jQuery.speed(speed, easing, callback);

		return this[ optall.queue === false ? "each" : "queue" ](function(){
		
			var opt = jQuery.extend({}, optall), p,
				hidden = this.nodeType == 1 && jQuery(this).is(":hidden"),
				self = this;
	
			for ( p in prop ) {
				if ( prop[p] == "hide" && hidden || prop[p] == "show" && !hidden )
					return opt.complete.call(this);

				if ( ( p == "height" || p == "width" ) && this.style ) {
					// Store display property
					opt.display = jQuery.css(this, "display");

					// Make sure that nothing sneaks out
					opt.overflow = this.style.overflow;
				}
			}

			if ( opt.overflow != null )
				this.style.overflow = "hidden";

			opt.curAnim = jQuery.extend({}, prop);

			jQuery.each( prop, function(name, val){
				var e = new jQuery.fx( self, opt, name );

				if ( /toggle|show|hide/.test(val) )
					e[ val == "toggle" ? hidden ? "show" : "hide" : val ]( prop );
				else {
					var parts = val.toString().match(/^([+-]=)?([\d+-.]+)(.*)$/),
						start = e.cur(true) || 0;

					if ( parts ) {
						var end = parseFloat(parts[2]),
							unit = parts[3] || "px";

						// We need to compute starting value
						if ( unit != "px" ) {
							self.style[ name ] = (end || 1) + unit;
							start = ((end || 1) / e.cur(true)) * start;
							self.style[ name ] = start + unit;
						}

						// If a +=/-= token was provided, we're doing a relative animation
						if ( parts[1] )
							end = ((parts[1] == "-=" ? -1 : 1) * end) + start;

						e.custom( start, end, unit );
					} else
						e.custom( start, val, "" );
				}
			});

			// For JS strict compliance
			return true;
		});
	},

	stop: function(clearQueue, gotoEnd){
		var timers = jQuery.timers;

		if (clearQueue)
			this.queue([]);

		this.each(function(){
			// go in reverse order so anything added to the queue during the loop is ignored
			for ( var i = timers.length - 1; i >= 0; i-- )
				if ( timers[i].elem == this ) {
					if (gotoEnd)
						// force the next step to be the last
						timers[i](true);
					timers.splice(i, 1);
				}
		});

		// start the next in the queue if the last step wasn't forced
		if (!gotoEnd)
			this.dequeue();

		return this;
	}

});

// jQuery back compat for $.toggle -> $.toggleVisibility rename
jQuery.fn._toggle = jQuery.fn.toggle; // Save the old toggle function
jQuery.fn.toggle  = jQuery.fn.toggleVisibility;

// Generate shortcuts for custom animations
jQuery.each({
	slideDown: genFx("show", 1),
	slideUp: genFx("hide", 1),
	slideToggle: genFx("toggle", 1),
	fadeIn: { opacity: "show" },
	fadeOut: { opacity: "hide" }
}, function( name, props ){
	jQuery.fn[ name ] = function( speed, callback ){
		return this.animate( props, speed, callback );
	};
});

jQuery.extend({

	speed: function(speed, easing, fn) {
		var opt = typeof speed === "object" ? speed : {
			complete: fn || !fn && easing ||
				jQuery.isFunction( speed ) && speed,
			duration: speed,
			easing: fn && easing || easing && !jQuery.isFunction(easing) && easing
		};

		opt.duration = jQuery.fx.off ? 0 : typeof opt.duration === "number" ? opt.duration :
			jQuery.fx.speeds[opt.duration] || jQuery.fx.speeds._default;

		// Queueing
		opt.old = opt.complete;
		opt.complete = function(){
			if ( opt.queue !== false )
				jQuery(this).dequeue();
			if ( jQuery.isFunction( opt.old ) )
				opt.old.call( this );
		};

		return opt;
	},

	easing: {
		linear: function( p, n, firstNum, diff ) {
			return firstNum + diff * p;
		},
		swing: function( p, n, firstNum, diff ) {
			return ((-Math.cos(p*Math.PI)/2) + 0.5) * diff + firstNum;
		}
	},

	timers: [],

	fx: function( elem, options, prop ){
		this.options = options;
		this.elem = elem;
		this.prop = prop;

		if ( !options.orig )
			options.orig = {};
	}

});

jQuery.fx.prototype = {

	// Simple function for setting a style value
	update: function(){
		if ( this.options.step )
			this.options.step.call( this.elem, this.now, this );

		(jQuery.fx.step[this.prop] || jQuery.fx.step._default)( this );

		// Set display property to block for height/width animations
		if ( ( this.prop == "height" || this.prop == "width" ) && this.elem.style )
			this.elem.style.display = "block";
	},

	// Get the current size
	cur: function(force){
		if ( this.elem[this.prop] != null && (!this.elem.style || this.elem.style[this.prop] == null) )
			return this.elem[ this.prop ];

		var r = parseFloat(jQuery.css(this.elem, this.prop, force));
		return r && r > -10000 ? r : parseFloat(jQuery.curCSS(this.elem, this.prop)) || 0;
	},

	// Start an animation from one number to another
	custom: function(from, to, unit){
		this.startTime = now();
		this.start = from;
		this.end = to;
		this.unit = unit || this.unit || "px";
		this.now = this.start;
		this.pos = this.state = 0;

		var self = this;
		function t(gotoEnd){
			return self.step(gotoEnd);
		}

		t.elem = this.elem;

		if ( t() && jQuery.timers.push(t) && !timerId ) {
			timerId = setInterval(function(){
				var timers = jQuery.timers;

				for ( var i = 0; i < timers.length; i++ )
					if ( !timers[i]() )
						timers.splice(i--, 1);

				if ( !timers.length ) {
					clearInterval( timerId );
					timerId = undefined;
				}
			}, 13);
		}
	},

	// Simple 'show' function
	show: function(){
		// Remember where we started, so that we can go back to it later
		this.options.orig[this.prop] = jQuery.attr( this.elem.style, this.prop );
		this.options.show = true;

		// Begin the animation
		// Make sure that we start at a small width/height to avoid any
		// flash of content
		this.custom(this.prop == "width" || this.prop == "height" ? 1 : 0, this.cur());

		// Start by showing the element
		jQuery(this.elem).show();
	},

	// Simple 'hide' function
	hide: function(){
		// Remember where we started, so that we can go back to it later
		this.options.orig[this.prop] = jQuery.attr( this.elem.style, this.prop );
		this.options.hide = true;

		// Begin the animation
		this.custom(this.cur(), 0);
	},

	// Each step of an animation
	step: function(gotoEnd){
		var t = now();

		if ( gotoEnd || t >= this.options.duration + this.startTime ) {
			this.now = this.end;
			this.pos = this.state = 1;
			this.update();

			this.options.curAnim[ this.prop ] = true;

			var done = true;
			for ( var i in this.options.curAnim )
				if ( this.options.curAnim[i] !== true )
					done = false;

			if ( done ) {
				if ( this.options.display != null ) {
					// Reset the overflow
					this.elem.style.overflow = this.options.overflow;

					// Reset the display
					this.elem.style.display = this.options.display;
					if ( jQuery.css(this.elem, "display") == "none" )
						this.elem.style.display = "block";
				}

				// Hide the element if the "hide" operation was done
				if ( this.options.hide )
					jQuery(this.elem).hide();

				// Reset the properties, if the item has been hidden or shown
				if ( this.options.hide || this.options.show )
					for ( var p in this.options.curAnim )
						jQuery.attr(this.elem.style, p, this.options.orig[p]);
					
				// Execute the complete function
				this.options.complete.call( this.elem );
			}

			return false;
		} else {
			var n = t - this.startTime;
			this.state = n / this.options.duration;

			// Perform the easing function, defaults to swing
			this.pos = jQuery.easing[this.options.easing || (jQuery.easing.swing ? "swing" : "linear")](this.state, n, 0, 1, this.options.duration);
			this.now = this.start + ((this.end - this.start) * this.pos);

			// Perform the next step of the animation
			this.update();
		}

		return true;
	}

};

jQuery.extend( jQuery.fx, {
	speeds:{
		slow: 600,
 		fast: 200,
 		// Default speed
 		_default: 400
	},
	step: {

		opacity: function(fx){
			jQuery.attr(fx.elem.style, "opacity", fx.now);
		},

		_default: function(fx){
			if ( fx.elem.style && fx.elem.style[ fx.prop ] != null )
				fx.elem.style[ fx.prop ] = fx.now + fx.unit;
			else
				fx.elem[ fx.prop ] = fx.now;
		}
	}
});