https://dvasoyza.ru/g/libs/jquery-bgdsize/jquery.bgdsize.js

1/*
2 * CSS Background-Size jQuery Plugin v.1.0
3 *
4 * By Aram Kocharyan, 2012.
5 * Released under the MIT licence.
6 * http://aramk.com/
7 */
8
9(function($) {
10
11	$.bgdSize = function(el, options) {
12		var base = this;
13
14		base.defaults = {
15			mode : '', // blank will do nothing, use 'cover' or 'contain'
16			repeatCount : 0,
17			repeatMax : 10,
18			repeatFreq : 100
19		};
20
21		base.$el = $(el);
22		base.el = el;
23
24		base.init = function() {
25			if (typeof options == 'string') {
26				base.options = $.extend(base.defaults, {
27					mode : options
28				});
29			} else {
30				base.options = $.extend(base.defaults, options);
31			}
32			base.repeat();
33		};
34
35		base.repeat = function() {
36			base.options.repeatCount++;
37			if (base.options.repeatCount > base.options.repeatMax) {
38				return;
39			}
40			base.scale();
41			if (base.done == false) {
42				base.done = true;
43				setTimeout(function() {
44					base.repeat();
45				}, base.options.repeatFreq);
46			}
47		};
48
49		base.scale = function() {
50			var mode;
51			if (base.options.mode == 'cover') {
52				mode = Math.max;
53			} else if (base.options.mode == 'contain') {
54				mode = Math.min;
55			} else {
56				return;
57			}
58
59			var parent = base.$el.parent();
60			if (!parent) {
61				return;
62			}
63			parent.css('overflow', 'hidden');
64			var width = base.$el.width();
65			var height = base.$el.height();
66			if (width == 0 || height == 0) {
67				base.done = false;
68				return;
69			}
70			var parentWidth = parent.width();
71			var parentHeight = parent.height();
72
73			var widthRatio = parentWidth / width;
74			var heightRatio = parentHeight / height;
75
76			var ratio = mode(widthRatio, heightRatio);
77
78			var newWidth = ratio * width;
79			var newHeight = ratio * height;
80			base.$el.width(newWidth);
81			base.$el.height(newHeight);
82
83			base.$el.css('margin-left', (parentWidth - newWidth) / 2);
84			base.$el.css('margin-top', (parentHeight - newHeight) / 2);
85		};
86
87		base.init();
88	};
89
90	$.fn.bgdSize = function(options) {
91		return this.each(function() {
92			(new $.bgdSize(this, options));
93		});
94	};
95
96})(jQuery);
97