https://www.psicologo-a-treviso.it/skype/scripts/pi.parallax.js

1/* Aura version: 1.8.6 */
2
3/*
4 Plugin: PI Parallax
5 Version 1.0.0
6 Author: Pavel Shlykov
7
8 Dual licensed under the MIT and GPL licenses:
9 http://www.opensource.org/licenses/mit-license.php
10 http://www.gnu.org/licenses/gpl.html
11 */
12
13jQuery(function($) {
14	var $w = $(window),
15		$d = $(document),
16		windowHeight = $w.height(),
17		elements = [];
18
19	$w.resize(function () {
20		windowHeight = $w.height();
21	});
22
23	$.fn.parallax = function () {
24
25		$(this).each(function () {
26
27			var $el = $(this),
28				el = {
29					$el: $el,
30					t: $el.offset().top,
31					x: $el.data('parallaxX') || '50%',
32					y: $el.data('parallaxY') || 0,
33					s: $el.data('parallaxSpeed') || 0.5,
34					h: getHeight($el, ($el.data('parallaxOuterHeight') || 1))
35				};
36
37			elements.push(el);
38
39		});
40
41	};
42
43	$d.on('piBoundChanged', function(){
44		checkParallaxState();
45	});
46	checkParallaxState();
47
48	function checkParallaxState(){
49		if(window.piCurrentBound == 'lg'){
50			enableParallax();
51		} else {
52			disableParallax();
53		}
54	}
55
56	function update() {
57		var scrollTop = $w.scrollTop();
58
59		for (var i = 0; i < elements.length; i++) {
60			var o = elements[i];
61				o.t = o.$el.offset().top;
62				o.h = getHeight(o.$el, 1);
63
64			if (o.t + o.h > scrollTop && o.t < scrollTop + windowHeight) {
65				o.$el.css('backgroundPosition', o.x + " " + Math.round((o.t - scrollTop + o.y) * o.s) + "px");
66			}
67		}
68	}
69
70	function getHeight($el, outerHeight) {
71		if (outerHeight) {
72			return $el.outerHeight(true);
73		} else {
74			return $el.height();
75		}
76	}
77
78	function enableParallax(){
79		$w.on('scroll.piParallax resize.piParallax', update);
80		update();
81	}
82
83	function disableParallax(){
84		$w.off('scroll.piParallax resize.piParallax');
85		for (var i = 0; i < elements.length; i++) {
86			var o = elements[i];
87			o.$el.css('backgroundPosition', '');
88		}
89	}
90
91
92});