owl.lazyload.js
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/**
* Lazy Plugin
* @version 2.1.0
* @author Bartosz Wojciechowski
* @author David Deutsch
* @license The MIT License (MIT)
*/
;(function($, window, document, undefined) {
/**
* Creates the lazy plugin.
* @class The Lazy Plugin
* @param {Owl} carousel - The Owl Carousel
*/
var Lazy = function(carousel) {
/**
* Reference to the core.
* @protected
* @type {Owl}
*/
this._core = carousel;
/**
* Already loaded items.
* @protected
* @type {Array.<jQuery>}
*/
this._loaded = [];
/**
* Event handlers.
* @protected
* @type {Object}
*/
this._handlers = {
'initialized.owl.carousel change.owl.carousel resized.owl.carousel': $.proxy(function(e) {
if (!e.namespace) {
return;
}
if (!this._core.settings || !this._core.settings.lazyLoad) {
return;
}
if ((e.property && e.property.name == 'position') || e.type == 'initialized') {
var settings = this._core.settings,
n = (settings.center && Math.ceil(settings.items / 2) || settings.items),
i = ((settings.center && n * -1) || 0),
position = (e.property && e.property.value !== undefined ? e.property.value : this._core.current()) + i,
clones = this._core.clones().length,
load = $.proxy(function(i, v) { this.load(v) }, this);
while (i++ < n) {
this.load(clones / 2 + this._core.relative(position));
clones && $.each(this._core.clones(this._core.relative(position)), load);
position++;
}
}
}, this)
};
// set the default options
this._core.options = $.extend({}, Lazy.Defaults, this._core.options);
// register event handler
this._core.$element.on(this._handlers);
};
/**
* Default options.
* @public
*/
Lazy.Defaults = {
lazyLoad: false
};
/**
* Loads all resources of an item at the specified position.
* @param {Number} position - The absolute position of the item.
* @protected
*/
Lazy.prototype.load = function(position) {
var $item = this._core.$stage.children().eq(position),
$elements = $item && $item.find('.owl-lazy');
if (!$elements || $.inArray($item.get(0), this._loaded) > -1) {
return;
}
$elements.each($.proxy(function(index, element) {
var $element = $(element), image,
url = (window.devicePixelRatio > 1 && $element.attr('data-src-retina')) || $element.attr('data-src');
this._core.trigger('load', { element: $element, url: url }, 'lazy');
if ($element.is('img')) {
$element.one('load.owl.lazy', $.proxy(function() {
$element.css('opacity', 1);
this._core.trigger('loaded', { element: $element, url: url }, 'lazy');
}, this)).attr('src', url);
} else {
image = new Image();
image.onload = $.proxy(function() {
$element.css({
'background-image': 'url("' + url + '")',
'opacity': '1'
});
this._core.trigger('loaded', { element: $element, url: url }, 'lazy');
}, this);
image.src = url;
}
}, this));
this._loaded.push($item.get(0));
};
/**
* Destroys the plugin.
* @public
*/
Lazy.prototype.destroy = function() {
var handler, property;
for (handler in this.handlers) {
this._core.$element.off(handler, this.handlers[handler]);
}
for (property in Object.getOwnPropertyNames(this)) {
typeof this[property] != 'function' && (this[property] = null);
}
};
$.fn.owlCarousel.Constructor.Plugins.Lazy = Lazy;
})(window.Zepto || window.jQuery, window, document);