https://amomassagem.com.br/scripts/pi.parallax.js

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