https://www.gov.hk/js/libs/jquery.cover.js?20161109.151942

1/*! 
2 * jQuery Cover plugin - v1.0.0 (https://github.com/greenish/jquery-cover)
3 * 
4 * Copyright (c) 2011 Philipp Adrian (www.philippadrian.com)
5 *
6 * The MIT Licence (http://opensource.org/licenses/MIT)
7 *   
8 * Permission is hereby granted, free of charge, to any person obtaining a copy
9 * of this software and associated documentation files (the "Software"), to deal
10 * in the Software without restriction, including without limitation the rights
11 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
12 * copies of the Software, and to permit persons to whom the Software is
13 * furnished to do so, subject to the following conditions: 
14
15 * The above copyright notice and this permission notice shall be included in
16 * all copies or substantial portions of the Software.
17
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
21 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
22 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
23 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
24 * THE SOFTWARE.
25 */
26
27(function($) {
28////////////////////////////////////////////////////////////////////////////////
29var cover=$.fn.cover = function (method){	
30	var call, args;
31	if(typeof(method) === 'object' || !method) {
32		args=arguments;
33		call="_init";
34	}
35	else if(cover[method]) {
36		args=Array.prototype.slice.call(arguments,1);
37		call=method;
38	}
39	else throw "Error: The method \""+method+"\" doesn't exist in jQuery Cover";
40	
41	return $(this).each(function(){
42//		Make sure to select the image (and not a wrapper)
43		var img=$(this).is("img") ? $(this) : $("img", this),
44			data = img.data("data");
45			
46//			IF already initialized -> update options.
47			if(call == "_init" && data) {
48				cover._opts(data, method, true);
49				return;				
50			}
51			data = data || {
52				self:$(this),
53				callbacks : []
54			};
55			
56		if(call=="_init") {
57			data.opts=method=="_init"?Array.prototype.slice.call(arguments,1):method;
58			args=[data];
59		}
60		else args=[data].concat(args);
61		img.data("data", data);
62		if(call=="_triggerCallback") return cover[call].apply(img, args);
63		else try { 
64				cover[call].apply(img, args);
65			}
66			catch(err){
67				if(err!="callbackReturnedFalse") throw err;
68			}
69	});
70};
71$.extend(cover, {
72	interval:false,
73////////////////////////////////////////////////////////////////////////////////
74	_init : function (data) {
75		
76//		Extends defaults into opts.
77		var opts=cover._opts(data, data.opts, true);
78		data.img = new Image();
79
80//		binding callbacks to make them available.
81		for(var callbacks in opts.callbacks) cover.bindCallback(data,callbacks,opts.callbacks[callbacks]);
82
83		data.img.src = data.self.attr("src");
84		data.self.wrap($("<div class=\"greenishCover height\"\><div\>"));
85		data.wrapper=data.self.parent().parent();
86		
87		if(opts.backgroundPosition) {
88			if(opts.backgroundPosition.search(/top/i) >= 0) data.wrapper.addClass("top");
89			else if(opts.backgroundPosition.search(/bottom/i) >= 0) data.wrapper.addClass("bottom");
90			if(opts.backgroundPosition.search(/left/i) >= 0) data.wrapper.addClass("left");
91			else if(opts.backgroundPosition.search(/right/i) >= 0) data.wrapper.addClass("right");
92		}
93		
94		if(opts.loadHidden) data.self.css({visibility:"hidden"});
95		data.self.cover("_triggerCallback","preLoading"); // #CALLBACK
96		if(!cover.interval) cover.interval=setInterval(cover._loading, 100);
97
98		data.opts.checkWindowResize && $(window)
99			.unbind("resize.cover")
100			.bind("resize.cover", function(){$(".greenishCover").cover("update")});
101	},
102////////////////////////////////////////////////////////////////////////////////
103	update : function() {
104		var that = $(this),
105			img=that.is("img") ? that : that.find("img"),
106			data = img.data("data"),
107			wrapper = data.wrapper,

108			current = wrapper.hasClass("height") ? "height":"width",
109			newRatio = wrapper.height()/wrapper.width() >= data.ratio ? "height":"width";
110
111		if(current !== newRatio) {
112			wrapper.addClass(newRatio).removeClass(current);
113			img.cover("_triggerCallback","ratioSwitch"); // #CALLBACK
114		}
115	},
116////////////////////////////////////////////////////////////////////////////////
117	_loading : function () {
118		cover.complete=true;
119		$(".greenishCover").each(function (){
120			var data = $("img", this).data("data"),
121				image= data.img;
122			if(!image || !image.complete || image.height <= 0 || image.width <= 0) {
123				cover.complete=false;
124				return;
125			}
126			data.ratio=image.height/image.width;
127			var marginTop=50/image.width*image.height; // Based on the fact that (marginTop 100% == width).
128			data.self.css({"marginTop":-marginTop+"%"});
129			if(data.opts.loadHidden) data.self.css({visibility:"visible"});
130			data.self.cover("_triggerCallback","postLoading"); // #CALLBACK
131			data.wrapper.cover("update");
132		});
133		if(cover.complete) {
134			clearInterval(cover.interval);
135			cover.interval=false;
136		}
137	},
138////////////////////////////////////////////////////////////////////////////////
139	bindCallback : function (data, callback, func) {
140		func=typeof(func)=="function"?[func]:func;
141		data.callbacks[callback]=data.callbacks[callback]||[];
142		for(var key in func) data.callbacks[callback].push(func[key]);
143	},
144////////////////////////////////////////////////////////////////////////////////
145	_triggerCallback : function (data, callback, param) {
146		if(!data.callbacks[callback] || data.callbacks[callback].length <= 0) return param;
147		for(var key in data.callbacks[callback]) 
148			if((param=data.callbacks[callback][key].apply(this, [data,param])) !== false) continue;
149			else throw "callbackReturnedFalse";
150		return param;
151	},	
152////////////////////////////////////////////////////////////////////////////////	
153	_opts : function (data, opts, save) {
154		opts=$.extend(true,{},this.defaults, data.opts||{}, opts||{});
155		if(save) data.opts=opts;
156		return opts;
157	},
158////////////////////////////////////////////////////////////////////////////////	
159	defaults : {
160		backgroundPosition:false,
161		callbacks: {},
162		checkWindowResize:true,
163		loadHidden : true
164	}
165});
166})(jQuery);
167