56 lines
1.4 KiB
JavaScript
56 lines
1.4 KiB
JavaScript
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/**
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* jQuery Unveil
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* A very lightweight jQuery plugin to lazy load images
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* http://luis-almeida.github.com/unveil
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*
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* Licensed under the MIT license.
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* Copyright 2013 Luís Almeida
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* https://github.com/luis-almeida
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*/
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;(function($) {
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$.fn.unveil = function(threshold, callback) {
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var $w = $(window),
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th = threshold || 0,
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retina = window.devicePixelRatio > 1,
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attrib = retina? "data-src-retina" : "data-src",
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images = this,
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loaded;
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this.one("unveil", function() {
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var source = this.getAttribute(attrib);
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source = source || this.getAttribute("data-src");
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if (source) {
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this.setAttribute("src", source);
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if (typeof callback === "function") callback.call(this);
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}
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});
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function unveil() {
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var inview = images.filter(function() {
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var $e = $(this);
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if ($e.is(":hidden")) return;
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var wt = $w.scrollTop(),
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wb = wt + $w.height(),
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et = $e.offset().top,
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eb = et + $e.height();
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return eb >= wt - th && et <= wb + th;
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});
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loaded = inview.trigger("unveil");
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images = images.not(loaded);
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}
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$w.on("scroll.unveil resize.unveil lookup.unveil", unveil);
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unveil();
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return this;
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};
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})(window.jQuery || window.Zepto);
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