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81 lines
1.9 KiB
81 lines
1.9 KiB
/**
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* @class Images
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* This class loads images and keeps them stored.
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*/
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function Images() {
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this.images = {};
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this.callback = undefined;
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}
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Images.prototype._resolveRelativeUrl = function(url){
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var img = document.createElement('img');
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img.src = url; // set string url
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url = img.src; // get qualified url
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img.src = null; // no server request
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return url;
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}
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/**
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* Set an onload callback function. This will be called each time an image
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* is loaded
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* @param {function} callback
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*/
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Images.prototype.setOnloadCallback = function(callback) {
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this.callback = callback;
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};
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/**
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*
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* @param {string} url Url of the image
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* @param {string} url Url of an image to use if the url image is not found
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* @return {Image} img The image object
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*/
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Images.prototype.load = function(url, brokenUrl) {
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var img = this.images[url];
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if (img === undefined) {
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// create the image
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var me = this;
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img = new Image();
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img.onload = function () {
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// IE11 fix -- thanks dponch!
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if (this.width == 0) {
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document.body.appendChild(this);
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this.width = this.offsetWidth;
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this.height = this.offsetHeight;
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document.body.removeChild(this);
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}
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if (me.callback) {
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me.images[url] = img;
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me.callback(this);
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}
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};
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img.onerror = function () {
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if (brokenUrl === undefined) {
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console.error("Could not load image:", url);
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delete this.src;
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if (me.callback) {
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me.callback(this);
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}
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}
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else if (this.src === me._resolveRelativeUrl(brokenUrl)){
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console.error("Could not load brokenImage:", brokenUrl);
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delete this.src;
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if (me.callback) {
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me.callback(this);
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}
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}
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else {
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this.src = brokenUrl;
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}
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};
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img.src = url;
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}
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return img;
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};
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module.exports = Images;
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