/usr/share/javascript/img.srcset/img.srcset.js is in libjs-img.srcset 2.0.0~20131003~dfsg-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 | /* imgsrcset - Img srcset polyfill for resolution responsive images. Authors & copyright (c) 2012: WebLinc, David Knight. */
// Imgsrcset
(function(win) {
'use strict';
var _viewport = win.document.documentElement,
_srcsetID = 0,
_srcsets = [],
_eventPrefix = '',
_addEvent = win.addEventListener || (_eventPrefix = 'on') && win.attachEvent,
_removeEvent = win.removeEventListener || win.detachEvent,
_srcExpr = /[^\s]+/g,
_digitExpr = /[0-9\.]+/g,
_timer = 0,
/*
_matches
*/
_matches = function(srcset) {
var srcList = (srcset.indexOf(',') !== -1 && srcset.split(',')) || [srcset],
srcIndex = srcList.length - 1,
srcLength = srcIndex,
list = null,
listIndex = 0,
src = '',
media = '';
if (srcIndex < 0) {
return;
}
do {
var list = srcList[srcLength - srcIndex].match(_srcExpr) || [],
listIndex = list.length;
while (listIndex--) {
var item = list[listIndex],
feature = 0,
digits = 0;
if (listIndex > 0) {
feature = (item.indexOf('w') !== -1 && (win.innerWidth || _viewport.clientWidth)) ||
(item.indexOf('h') !== -1 && (win.innerHeight || _viewport.clientHeight)) ||
(item.indexOf('x') !== -1 && (win.devicePixelRatio || 1));
digits = Number(item.match(_digitExpr));
if (feature && digits && digits > feature) {
break;
}
} else {
src = item;
media = srcList[srcIndex];
}
}
} while (srcIndex--);
return (src && media && {src: src, media: media}) || false;
},
/*
watch
*/
_watch = function(evt) {
clearTimeout(_timer);
_timer = setTimeout(function() {
var srcset = null,
srcsetIndex = _srcsetID - 1,
srcsetLength = srcsetIndex,
match = false;
do {
srcset = _srcsets[srcsetLength - srcsetIndex];
// If img element does not have a parent, remove array index to prevent caching
if (!srcset.element.parentNode) {
_srcsetID--;
srcset.splice(srcsetIndex, 1);
continue;
}
match = _matches(srcset.media);
if (match && (srcset.matches !== match.media)) {
srcset.matches = match.media;
srcset.element.src = match.src;
} else if (!match) {
srcset.matches = false;
srcset.src && (srcset.element.src = srcset.src);
}
} while(srcsetIndex--);
}, 10);
},
/*
init
*/
_init = function() {
_removeEvent(_eventPrefix + 'load', _init);
win.Imgsrcset.parse();
_watch();
// Processes '_srcsets' array and determines which source to use
// '_watch' will clear out any images from the array that do not have parents, which should eliminate element caching
_addEvent(_eventPrefix + 'resize', _watch);
_addEvent(_eventPrefix + 'orientationchange', _watch);
};
/*
imgsrcset
*/
win.Imgsrcset = {
/*
parse
Called on '_init' and can also be called if new images are added/removed
*/
parse: function() {
_srcsets = [];
var imgs = win.document.getElementsByTagName('img') || [],
imgIndex = imgs.length - 1,
imgLength = imgIndex,
img = null,
srcset = '';
do {
img = imgs[imgLength - imgIndex];
srcset = img.getAttribute('srcset') || '';
if (!srcset) {
continue;
}
_srcsetID = _srcsets.push({
element : img,
media : srcset,
matches : false,
src : img.getAttribute('src') || ''
});
} while(imgIndex--);
}
};
// Set up listeners
_addEvent(_eventPrefix + 'load', _init);
})(window);
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