Stackedit/js/libs/jquery.waitforimages.js

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2013-06-02 00:38:23 +00:00
/*
* waitForImages 1.4.2
* -------------------
* Provides a callback when all images have loaded in your given selector.
* https://github.com/alexanderdickson/waitForImages
*
* Copyright (c) 2013 Alex Dickson
* Licensed under the MIT license.
*/
(function ($) {
// Namespace all events.
var eventNamespace = 'waitForImages';
// CSS properties which contain references to images.
$.waitForImages = {
hasImageProperties: ['backgroundImage', 'listStyleImage', 'borderImage', 'borderCornerImage']
};
// Custom selector to find `img` elements that have a valid `src` attribute and have not already loaded.
$.expr[':'].uncached = function (obj) {
// Ensure we are dealing with an `img` element with a valid `src` attribute.
if (!$(obj).is('img[src!=""]')) {
return false;
}
// Firefox's `complete` property will always be `true` even if the image has not been downloaded.
// Doing it this way works in Firefox.
var img = new Image();
img.src = obj.src;
return !img.complete;
};
$.fn.waitForImages = function (finishedCallback, eachCallback, waitForAll) {
var allImgsLength = 0;
var allImgsLoaded = 0;
// Handle options object.
if ($.isPlainObject(arguments[0])) {
waitForAll = arguments[0].waitForAll;
eachCallback = arguments[0].each;
// This must be last as arguments[0]
// is aliased with finishedCallback.
finishedCallback = arguments[0].finished;
}
// Handle missing callbacks.
finishedCallback = finishedCallback || $.noop;
eachCallback = eachCallback || $.noop;
// Convert waitForAll to Boolean
waitForAll = !! waitForAll;
// Ensure callbacks are functions.
if (!$.isFunction(finishedCallback) || !$.isFunction(eachCallback)) {
throw new TypeError('An invalid callback was supplied.');
}
return this.each(function () {
// Build a list of all imgs, dependent on what images will be considered.
var obj = $(this);
var allImgs = [];
// CSS properties which may contain an image.
var hasImgProperties = $.waitForImages.hasImageProperties || [];
// To match `url()` references.
// Spec: http://www.w3.org/TR/CSS2/syndata.html#value-def-uri
var matchUrl = /url\(\s*(['"]?)(.*?)\1\s*\)/g;
if (waitForAll) {
// Get all elements (including the original), as any one of them could have a background image.
obj.find('*').andSelf().each(function () {
var element = $(this);
// If an `img` element, add it. But keep iterating in case it has a background image too.
if (element.is('img:uncached')) {
allImgs.push({
src: element.attr('src'),
element: element[0]
});
}
$.each(hasImgProperties, function (i, property) {
var propertyValue = element.css(property);
var match;
// If it doesn't contain this property, skip.
if (!propertyValue) {
return true;
}
// Get all url() of this element.
while (match = matchUrl.exec(propertyValue)) {
allImgs.push({
src: match[2],
element: element[0]
});
}
});
});
} else {
// For images only, the task is simpler.
obj.find('img:uncached')
.each(function () {
allImgs.push({
src: this.src,
element: this
});
});
}
allImgsLength = allImgs.length;
allImgsLoaded = 0;
// If no images found, don't bother.
if (allImgsLength === 0) {
finishedCallback.call(obj[0]);
}
$.each(allImgs, function (i, img) {
var image = new Image();
// Handle the image loading and error with the same callback.
$(image).bind('load.' + eventNamespace + ' error.' + eventNamespace, function (event) {
allImgsLoaded++;
// If an error occurred with loading the image, set the third argument accordingly.
eachCallback.call(img.element, allImgsLoaded, allImgsLength, event.type == 'load');
if (allImgsLoaded == allImgsLength) {
finishedCallback.call(obj[0]);
return false;
}
});
image.src = img.src;
});
});
};
}(jQuery));