/*
 * stickyfloat - jQuery plugin for verticaly floating anything in a constrained area
 *
 * Example: jQuery('#menu').stickyfloat({duration: 400});
 * parameters:
 * duration - the duration of the animation
 * startOffset - the amount of scroll offset after it the animations kicks in
 * offsetY - the offset from the top when the object is animated
 * lockBottom - 'true' by default, set to false if you don't want your floating box to stop at parent's bottom
 * $Version: 05.16.2009 r1
 * Copyright (c) 2009 Yair Even-Or
 * vsync.design@gmail.com
 */

$.fn.stickyfloat = function(options, lockBottom) {
	var $obj = this;
	var parentPaddingTop = parseInt($obj.parent().css('padding-top'));
	var startOffset = $obj.parent().offset().top;
	var opts = $.extend( {
		startOffset : startOffset,
		offsetY : parentPaddingTop,
		duration : 200,
		lockBottom : true
	}, options);

	$obj.css( {
		position : 'absolute'
	});

	if (opts.lockBottom) {
		var bottomPos = $obj.parent().height() - $obj.height()
				+ parentPaddingTop; // get the maximum scrollTop value
		if (bottomPos < 0)
			bottomPos = 0;
	}

	$(window)
			.scroll( function() {
				$obj.stop(); // stop all calculations on scroll event

					var pastStartOffset = $(document).scrollTop() > opts.startOffset; // check
																						// if
																						// the
																						// window
																						// was
																						// scrolled
																						// down
																						// more
																						// than
																						// the
																						// start
																						// offset
																						// declared.
					var objFartherThanTopPos = $obj.offset().top > startOffset; // check
																				// if
																				// the
																				// object
																				// is
																				// at
																				// it's
																				// top
																				// position
																				// (starting
																				// point)
					var objBiggerThanWindow = $obj.outerHeight() < $(window)
							.height(); // if the window size is smaller than
										// the Obj size, then do not animate.

					// if window scrolled down more than startOffset OR obj
					// position is greater than
					// the top position possible (+ offsetY) AND window size
					// must be bigger than Obj size
					if ((pastStartOffset || objFartherThanTopPos)
							&& objBiggerThanWindow) {
						var newpos = ($(document).scrollTop() - startOffset + opts.offsetY);
						if (newpos > bottomPos)
							newpos = bottomPos;
						if ($(document).scrollTop() < opts.startOffset) // if
																		// window
																		// scrolled
																		// <
																		// starting
																		// offset,
																		// then
																		// reset
																		// Obj
																		// position
																		// (opts.offsetY);
							newpos = parentPaddingTop;

						$obj.animate( {
							top : newpos
						}, opts.duration);
					}
				});
};