https://clearbraces-direct.co.uk/shop/wp-content/themes/clearbraces-direct/js/retina.js

1/*!
2 * Retina.js v1.3.0
3 *
4 * Copyright 2014 Imulus, LLC
5 * Released under the MIT license
6 *
7 * Retina.js is an open source script that makes it easy to serve
8 * high-resolution images to devices with retina displays.
9 */
10
11(function() {
12    var root = (typeof exports === 'undefined' ? window : exports);
13    var config = {
14        // An option to choose a suffix for 2x images
15        retinaImageSuffix : '@2x',
16
17        // Ensure Content-Type is an image before trying to load @2x image
18        // https://github.com/imulus/retinajs/pull/45)
19        check_mime_type: true,
20
21        // Resize high-resolution images to original image's pixel dimensions
22        // https://github.com/imulus/retinajs/issues/8
23        force_original_dimensions: true
24    };
25
26    function Retina() {}
27
28    root.Retina = Retina;
29
30    Retina.configure = function(options) {
31        if (options === null) { options = {}; }
32        for (var prop in options) { if (options.hasOwnProperty(prop)) { config[prop] = options[prop]; } }
33    };
34
35    Retina.init = function(context) {
36        if (context === null) { context = root; }
37        var existing_onload = context.onload || function(){};
38        context.onload = function() {
39            var images = document.getElementsByTagName('img'), retinaImages = [], i, image;
40            for (i = 0; i < images.length; i += 1) {
41                image = images[i];
42                if (!!!image.getAttributeNode('data-no-retina')) { retinaImages.push(new RetinaImage(image)); }
43            }
44            existing_onload();
45        };
46    };
47
48    Retina.isRetina = function(){
49        var mediaQuery = '(-webkit-min-device-pixel-ratio: 1.5), (min--moz-device-pixel-ratio: 1.5), (-o-min-device-pixel-ratio: 3/2), (min-resolution: 1.5dppx)';
50        if (root.devicePixelRatio > 1) { return true; }
51        if (root.matchMedia && root.matchMedia(mediaQuery).matches) { return true; }
52        return false;
53    };
54
55    var regexMatch = /\.\w+$/;
56    function suffixReplace (match) { return config.retinaImageSuffix + match; }
57    function RetinaImagePath(path, at_2x_path) {
58        this.path = path || '';
59        if (typeof at_2x_path !== 'undefined' && at_2x_path !== null) {
60            this.at_2x_path = at_2x_path;
61            this.perform_check = false;
62        } else {
63            if (undefined !== document.createElement) {
64                var locationObject = document.createElement('a');
65                locationObject.href = this.path;
66                locationObject.pathname = locationObject.pathname.replace(regexMatch, suffixReplace);
67                this.at_2x_path = locationObject.href;
68            } else {
69                var parts = this.path.split('?');
70                parts[0] = parts[0].replace(regexMatch, suffixReplace);
71                this.at_2x_path = parts.join('?');
72            }
73            this.perform_check = true;
74        }
75    }
76
77    root.RetinaImagePath = RetinaImagePath;
78    RetinaImagePath.confirmed_paths = [];
79    RetinaImagePath.prototype.is_external = function() {
80        return !!(this.path.match(/^https?\:/i) && !this.path.match('//' + document.domain) );
81    };
82
83    RetinaImagePath.prototype.check_2x_variant = function(callback) {
84        var http, that = this;
85        if (this.is_external()) {
86            return callback(false);
87        } else if (!this.perform_check && typeof this.at_2x_path !== 'undefined' && this.at_2x_path !== null) {
88            return callback(true);
89        } else if (this.at_2x_path in RetinaImagePath.confirmed_paths) {
90            return callback(true);
91        } else {
92            http = new XMLHttpRequest();
93            http.open('HEAD', this.at_2x_path);
94            http.onreadystatechange = function() {
95                if (http.readyState !== 4) { return callback(false); }
96                if (http.status >= 200 && http.status <= 399) {
97                    if (config.check_mime_type) { var type = http.getResponseHeader('Content-Type'); if (type === null || !type.match(/^image/i)) { return callback(false); } }
98                    RetinaImagePath.confirmed_paths.push(that.at_2x_path); return callback(true);
99                } else { return callback(false); }
100            };
101            http.send();
102        }
103    };
104    function RetinaImage(el) { this.el = el; this.path = new RetinaImagePath(this.el.getAttribute('src'), this.el.getAttribute('data-at2x')); var that = this; this.path.check_2x_variant(function(hasVariant) { if (hasVariant) { that.swap(); } }); }
105    root.RetinaImage = RetinaImage;
106    RetinaImage.prototype.swap = function(path) {
107        if (typeof path === 'undefined') { path = this.path.at_2x_path; }
108        var that = this;
109        function load() {
110            if (! that.el.complete) { setTimeout(load, 5); } else {
111                if (config.force_original_dimensions) { that.el.setAttribute('width', that.el.offsetWidth); that.el.setAttribute('height', that.el.offsetHeight); }
112                that.el.setAttribute('src', path);
113            }
114        }
115        load();
116    };
117    if (Retina.isRetina()) { Retina.init(root); }
118})();