https://ebooks.edu.gr/ebooks/static/js/holder.js?v1.1

1/*
2 * The contents of this file are subject to the license and copyright
3 * detailed in the LICENSE and NOTICE files at the root of the source
4 * tree and available online at
5 *
6 * http://www.dspace.org/license/
7 */
8/*
9
10Holder - 2.0 - client side image placeholders
11(c) 2012-2013 Ivan Malopinsky / http://imsky.co
12
13Provided under the Apache 2.0 License: http://www.apache.org/licenses/LICENSE-2.0
14Commercial use requires attribution.
15
16*/
17
18var Holder = Holder || {};
19(function (app, win) {
20
21var preempted = false,
22fallback = false,
23canvas = document.createElement('canvas');
24
25//getElementsByClassName polyfill
26document.getElementsByClassName||(document.getElementsByClassName=function(e){var t=document,n,r,i,s=[];if(t.querySelectorAll)return t.querySelectorAll("."+e);if(t.evaluate){r=".//*[contains(concat(' ', @class, ' '), ' "+e+" ')]",n=t.evaluate(r,t,null,0,null);while(i=n.iterateNext())s.push(i)}else{n=t.getElementsByTagName("*"),r=new RegExp("(^|\\s)"+e+"(\\s|$)");for(i=0;i<n.length;i++)r.test(n[i].className)&&s.push(n[i])}return s})
27
28//getComputedStyle polyfill
29window.getComputedStyle||(window.getComputedStyle=function(e,t){return this.el=e,this.getPropertyValue=function(t){var n=/(\-([a-z]){1})/g;return t=="float"&&(t="styleFloat"),n.test(t)&&(t=t.replace(n,function(){return arguments[2].toUpperCase()})),e.currentStyle[t]?e.currentStyle[t]:null},this})
30
31//http://javascript.nwbox.com/ContentLoaded by Diego Perini with modifications
32function contentLoaded(n,t){var l="complete",s="readystatechange",u=!1,h=u,c=!0,i=n.document,a=i.documentElement,e=i.addEventListener?"addEventListener":"attachEvent",v=i.addEventListener?"removeEventListener":"detachEvent",f=i.addEventListener?"":"on",r=function(e){(e.type!=s||i.readyState==l)&&((e.type=="load"?n:i)[v](f+e.type,r,u),!h&&(h=!0)&&t.call(n,null))},o=function(){try{a.doScroll("left")}catch(n){setTimeout(o,50);return}r("poll")};if(i.readyState==l)t.call(n,"lazy");else{if(i.createEventObject&&a.doScroll){try{c=!n.frameElement}catch(y){}c&&o()}i[e](f+"DOMContentLoaded",r,u),i[e](f+s,r,u),n[e](f+"load",r,u)}};
33
34//https://gist.github.com/991057 by Jed Schmidt with modifications
35function selector(a){
36	a=a.match(/^(\W)?(.*)/);var b=document["getElement"+(a[1]?a[1]=="#"?"ById":"sByClassName":"sByTagName")](a[2]);
37	var ret=[];	b!=null&&(b.length?ret=b:b.length==0?ret=b:ret=[b]);	return ret;
38}
39
40//shallow object property extend
41function extend(a,b){var c={};for(var d in a)c[d]=a[d];for(var e in b)c[e]=b[e];return c}
42
43//hasOwnProperty polyfill
44if (!Object.prototype.hasOwnProperty)
45	Object.prototype.hasOwnProperty = function(prop) {
46		var proto = this.__proto__ || this.constructor.prototype;
47		return (prop in this) && (!(prop in proto) || proto[prop] !== this[prop]);
48	}
49
50function text_size(width, height, template) {
51	height = parseInt(height,10);
52	width = parseInt(width,10);
53	var bigSide = Math.max(height, width)
54	var smallSide = Math.min(height, width)
55	var scale = 1 / 12;
56	var newHeight = Math.min(smallSide * 0.75, 0.75 * bigSide * scale);
57	return {
58		height: Math.round(Math.max(template.size, newHeight))
59	}
60}
61
62function draw(ctx, dimensions, template, ratio) {
63	var ts = text_size(dimensions.width, dimensions.height, template);
64	var text_height = ts.height;
65	var width = dimensions.width * ratio,
66		height = dimensions.height * ratio;
67	var font = template.font ? template.font : "sans-serif";
68	canvas.width = width;
69	canvas.height = height;
70	ctx.textAlign = "center";
71	ctx.textBaseline = "middle";
72	ctx.fillStyle = template.background;
73	ctx.fillRect(0, 0, width, height);
74	ctx.fillStyle = template.foreground;
75	ctx.font = "bold " + text_height + "px " + font;
76	var text = template.text ? template.text : (Math.floor(dimensions.width) + "x" + Math.floor(dimensions.height));
77	var text_width = ctx.measureText(text).width;
78	if (text_width / width >= 0.75) {
79		text_height = Math.floor(text_height * 0.75 * (width/text_width));
80	}
81	//Resetting font size if necessary
82	ctx.font = "bold " + (text_height * ratio) + "px " + font;
83	ctx.fillText(text, (width / 2), (height / 2), width);
84	return canvas.toDataURL("image/png");
85}
86
87function render(mode, el, holder, src) {
88	var dimensions = holder.dimensions,
89		theme = holder.theme,
90		text = holder.text ? decodeURIComponent(holder.text) : holder.text;
91	var dimensions_caption = dimensions.width + "x" + dimensions.height;
92	theme = (text ? extend(theme, {
93		text: text
94	}) : theme);
95	theme = (holder.font ? extend(theme, {
96		font: holder.font
97	}) : theme);
98	if (mode == "image") {
99		el.setAttribute("data-src", src);
100		el.setAttribute("alt", text ? text : theme.text ? theme.text + " [" + dimensions_caption + "]" : dimensions_caption);
101		if (fallback || !holder.auto) {
102			el.style.width = dimensions.width + "px";
103			el.style.height = dimensions.height + "px";
104		}
105		if (fallback) {
106			el.style.backgroundColor = theme.background;
107		} else {
108			el.setAttribute("src", draw(ctx, dimensions, theme, ratio));
109		}
110	} else if (mode == "background") {
111		if (!fallback) {
112			el.style.backgroundImage = "url(" + draw(ctx, dimensions, theme, ratio) + ")";
113			el.style.backgroundSize = dimensions.width + "px " + dimensions.height + "px";
114		}
115	} else if (mode == "fluid") {
116		el.setAttribute("data-src", src);
117		el.setAttribute("alt", text ? text : theme.text ? theme.text + " [" + dimensions_caption + "]" : dimensions_caption);
118		if (dimensions.height.substr(-1) == "%") {
119			el.style.height = dimensions.height
120		} else {
121			el.style.height = dimensions.height + "px"
122		}
123		if (dimensions.width.substr(-1) == "%") {
124			el.style.width = dimensions.width
125		} else {
126			el.style.width = dimensions.width + "px"
127		}
128		if (el.style.display == "inline" || el.style.display == "") {
129			el.style.display = "block";
130		}
131		if (fallback) {
132			el.style.backgroundColor = theme.background;
133		} else {
134			el.holderData = holder;
135			fluid_images.push(el);
136			fluid_update(el);
137		}
138	}
139};
140
141function fluid_update(element) {
142	var images;
143	if (element.nodeType == null) {
144		images = fluid_images;
145	} else {
146		images = [element]
147	}
148	for (i in images) {
149		var el = images[i]
150		if (el.holderData) {
151			var holder = el.holderData;
152			el.setAttribute("src", draw(ctx, {
153				height: el.clientHeight,
154				width: el.clientWidth
155			}, holder.theme, ratio));
156		}
157	}
158}
159
160function parse_flags(flags, options) {
161
162	var ret = {
163		theme: settings.themes.gray
164	}, render = false;

165
166	for (sl = flags.length, j = 0; j < sl; j++) {
167		var flag = flags[j];
168		if (app.flags.dimensions.match(flag)) {
169			render = true;
170			ret.dimensions = app.flags.dimensions.output(flag);
171		} else if (app.flags.fluid.match(flag)) {
172			render = true;
173			ret.dimensions = app.flags.fluid.output(flag);
174			ret.fluid = true;
175		} else if (app.flags.colors.match(flag)) {
176			ret.theme = app.flags.colors.output(flag);
177		} else if (options.themes[flag]) {
178			//If a theme is specified, it will override custom colors
179			ret.theme = options.themes[flag];
180		} else if (app.flags.text.match(flag)) {
181			ret.text = app.flags.text.output(flag);
182		} else if (app.flags.font.match(flag)) {
183			ret.font = app.flags.font.output(flag);
184		} else if (app.flags.auto.match(flag)) {
185			ret.auto = true;
186		}
187	}
188
189	return render ? ret : false;
190
191};
192
193
194
195if (!canvas.getContext) {
196	fallback = true;
197} else {
198	if (canvas.toDataURL("image/png")
199		.indexOf("data:image/png") < 0) {
200		//Android doesn't support data URI
201		fallback = true;
202	} else {
203		var ctx = canvas.getContext("2d");
204	}
205}
206
207var dpr = 1, bsr = 1;
208	
209if(!fallback){
210    dpr = window.devicePixelRatio || 1,
211    bsr = ctx.webkitBackingStorePixelRatio || ctx.mozBackingStorePixelRatio || ctx.msBackingStorePixelRatio || ctx.oBackingStorePixelRatio || ctx.backingStorePixelRatio || 1;
212}
213
214var ratio = dpr / bsr;
215
216var fluid_images = [];
217
218var settings = {
219	domain: "holder.js",
220	images: "img",
221	bgnodes: ".holderjs",
222	themes: {
223		"gray": {
224			background: "#eee",
225			foreground: "#aaa",
226			size: 12
227		},
228		"social": {
229			background: "#3a5a97",
230			foreground: "#fff",
231			size: 12
232		},
233		"industrial": {
234			background: "#434A52",
235			foreground: "#C2F200",
236			size: 12
237		}
238	},
239	stylesheet: ".holderjs-fluid {font-size:16px;font-weight:bold;text-align:center;font-family:sans-serif;margin:0}"
240};
241
242
243app.flags = {
244	dimensions: {
245		regex: /^(\d+)x(\d+)$/,
246		output: function (val) {
247			var exec = this.regex.exec(val);
248			return {
249				width: +exec[1],
250				height: +exec[2]
251			}
252		}
253	},
254	fluid: {
255		regex: /^([0-9%]+)x([0-9%]+)$/,
256		output: function (val) {
257			var exec = this.regex.exec(val);
258			return {
259				width: exec[1],
260				height: exec[2]
261			}
262		}
263	},
264	colors: {
265		regex: /#([0-9a-f]{3,})\:#([0-9a-f]{3,})/i,
266		output: function (val) {
267			var exec = this.regex.exec(val);
268			return {
269				size: settings.themes.gray.size,
270				foreground: "#" + exec[2],
271				background: "#" + exec[1]
272			}
273		}
274	},
275	text: {
276		regex: /text\:(.*)/,
277		output: function (val) {
278			return this.regex.exec(val)[1];
279		}
280	},
281	font: {
282		regex: /font\:(.*)/,
283		output: function (val) {
284			return this.regex.exec(val)[1];
285		}
286	},
287	auto: {
288		regex: /^auto$/
289	}
290}
291
292for (var flag in app.flags) {
293	if (!app.flags.hasOwnProperty(flag)) continue;
294	app.flags[flag].match = function (val) {
295		return val.match(this.regex)
296	}
297}
298
299app.add_theme = function (name, theme) {
300	name != null && theme != null && (settings.themes[name] = theme);
301	return app;
302};
303
304app.add_image = function (src, el) {
305	var node = selector(el);
306	if (node.length) {
307		for (var i = 0, l = node.length; i < l; i++) {
308			var img = document.createElement("img")
309			img.setAttribute("data-src", src);
310			node[i].appendChild(img);
311		}
312	}
313	return app;
314};
315
316app.run = function (o) {
317	var options = extend(settings, o),
318	    images = [], imageNodes = [], bgnodes = [];
319	    
320	if(typeof(options.images) == "string"){
321	    imageNodes = selector(options.images);
322	}
323	else if (window.NodeList && options.images instanceof window.NodeList) {
324		imageNodes = options.images;
325	} else if (window.Node && options.images instanceof window.Node) {
326		imageNodes = [options.images];
327	}
328
329	if(typeof(options.bgnodes) == "string"){
330	    bgnodes = selector(options.bgnodes);
331	} else if (window.NodeList && options.elements instanceof window.NodeList) {
332		bgnodes = options.bgnodes;
333	} else if (window.Node && options.bgnodes instanceof window.Node) {
334		bgnodes = [options.bgnodes];
335	}
336
337	preempted = true;
338
339	for (i = 0, l = imageNodes.length; i < l; i++) images.push(imageNodes[i]);
340
341	var holdercss = document.getElementById("holderjs-style");
342	if (!holdercss) {
343		holdercss = document.createElement("style");
344		holdercss.setAttribute("id", "holderjs-style");
345		holdercss.type = "text/css";
346		document.getElementsByTagName("head")[0].appendChild(holdercss);
347	}
348	
349	if (!options.nocss) {
350	    if (holdercss.styleSheet) {
351		    holdercss.styleSheet.cssText += options.stylesheet;
352	    } else {
353		    holdercss.appendChild(document.createTextNode(options.stylesheet));
354	    }
355	}
356
357	var cssregex = new RegExp(options.domain + "\/(.*?)\"?\\)");
358
359	for (var l = bgnodes.length, i = 0; i < l; i++) {
360		var src = window.getComputedStyle(bgnodes[i], null)
361			.getPropertyValue("background-image");
362		var flags = src.match(cssregex);
363		var bgsrc = bgnodes[i].getAttribute("data-background-src");
364
365		if (flags) {
366			var holder = parse_flags(flags[1].split("/"), options);
367			if (holder) {
368				render("background", bgnodes[i], holder, src);
369			}
370		}
371		else if(bgsrc != null){
372		    var holder = parse_flags(bgsrc.substr(bgsrc.lastIndexOf(options.domain) + options.domain.length + 1)
373				.split("/"), options);
374		    if(holder){
375			render("background", bgnodes[i], holder, src);
376		    }
377		}
378	}
379
380	for (l = images.length, i = 0; i < l; i++) {
381	    
382		var attr_src = attr_data_src = src = null;
383		
384		try{
385		    attr_src = images[i].getAttribute("src");
386		    attr_datasrc = images[i].getAttribute("data-src");
387		}catch(e){}
388				
389		if (attr_datasrc == null && !! attr_src && attr_src.indexOf(options.domain) >= 0) {
390			src = attr_src;
391		} else if ( !! attr_datasrc && attr_datasrc.indexOf(options.domain) >= 0) {
392			src = attr_datasrc;
393		}
394		
395		if (src) {
396			var holder = parse_flags(src.substr(src.lastIndexOf(options.domain) + options.domain.length + 1)
397				.split("/"), options);
398			if (holder) {
399				if (holder.fluid) {
400					render("fluid", images[i], holder, src)
401				} else {
402					render("image", images[i], holder, src);
403				}
404			}
405		}
406	}
407	return app;
408};
409
410contentLoaded(win, function () {
411	if (window.addEventListener) {
412		window.addEventListener("resize", fluid_update, false);
413		window.addEventListener("orientationchange", fluid_update, false);
414	} else {
415		window.attachEvent("onresize", fluid_update)
416	}
417	preempted || app.run();
418});
419
420if (typeof define === "function" && define.amd) {
421	define("Holder", [], function () {
422		return app;
423	});
424}
425
426})(Holder, window);