/** @language chinese
 * LLoader 类可用于加载图像（JPG、PNG 或 GIF）文件。使用 load() 方法来启动加载。
 * @class LLoader
 * @extends LEventDispatcher
 * @constructor
 * @since 1.0.0
 * @public
 */
var LLoader = (function () {
	function LLoader () {
		var s = this;
		LExtends(s, LEventDispatcher, []);
		s.type = "LLoader";
	}
	LLoader.TYPE_BITMAPDATE = "bitmapData";
	/** @language chinese
	 * 将 JPEG、渐进式 JPEG、非动画 GIF 或 PNG 文件加载到此 LLoader 对象的子对象中。如果加载 GIF 动画文件，将仅显示第一帧。
	 * @method load
	 * @param {String} url 所请求的 URL。
	 * @param {String} type 读取文件种类，目前只支持"bitmapData"。
	 * @param {Boolean} xhr 是否利用xhr来读取图片。默认为false。
	 * @example
	 * 	LInit(1000/50,"legend",800,450,main);
	 * 	var loader;
	 * 	function main(){
	 * 		LGlobal.setDebug(true);
	 * 		loader = new LLoader();
	 * 		loader.addEventListener(LEvent.COMPLETE, loadBitmapdata); 
	 * 		loader.load("lufylegend.js.png", "bitmapData");
	 * 	}
	 * 	function loadBitmapdata (event) {
	 * 		trace(loader.objectIndex == event.currentTarget.objectIndex);//true
	 * 		trace(event.currentTarget.content == event.target);//true
	 * 		var bitmapdata = new LBitmapData(event.target);  
	 * 		var bitmap = new LBitmap(bitmapdata);
	 * 		addChild(bitmap);
	 * 	}
	 * @examplelink <p><a href="../../../api/LLoader/index.html" target="_blank">测试链接</a></p>
	 * @public
	 * @since 1.0.0
	 */
	LLoader.prototype.load = function (u, t, xhr) {
		var s = this;
		if (!t) {
			t = LLoader.TYPE_BITMAPDATE;
		}
		s.loadtype = t;
		s.useXHR = xhr && !LAjax.local && LAjax.canUseBlob;
		if (t == LLoader.TYPE_BITMAPDATE) {
			if(s.useXHR){
				LAjax.responseType = LAjax.ARRAY_BUFFER;
				LAjax.progress = function(e){
					var event = new LEvent(LEvent.PROGRESS);
					event.currentTarget = s;
					event.target = e.currentTarget;
					event.loaded = e.loaded;
					event.total = e.total;
					event.responseURL = e.responseURL;
					s.dispatchEvent(event);
				};
				LAjax.post(u, {}, function(response){
					var blob;
					try {
						blob = new Blob([response], {type : 'image/png'});
					} catch (e) {
						if(e.name === 'TypeError' && window.BlobBuilder){
							var builder = new BlobBuilder();
							builder.append(response);
							blob = builder.getBlob();
						}else{
							blob = null;
							s.useXHR = false;
						}
					}
					if(s.useXHR){
						u = s.createObjectURL(blob);
					}
					s.loadStart(u);
				}, function(request){
					var event = new LEvent(LEvent.ERROR);
					event.currentTarget = s;
					event.target = request;
					event.responseURL = request.responseURL;
					s.dispatchEvent(event);
				});
			}else{
				s.loadStart(u);
			}
		}
	};
	LLoader.prototype.loadStart = function(u){
		var s = this;
		s.content = new Image();
		s.content.onload = function () {
			s.content.onload = null;
			var event = new LEvent(LEvent.COMPLETE);
			event.currentTarget = s;
			event.target = s.content;
			if(s.useXHR){
				s.revokeObjectURL(s.content.src);
			}
			s.dispatchEvent(event);
			delete s.content;
		};
		if(!s.useXHR){
			s.content.onerror = function(e){
				var event = new LEvent(LEvent.ERROR);
				event.currentTarget = s;
				event.target = e.target;
				event.responseURL = e.target.src;
				s.dispatchEvent(event);
			};
		}
		s.content.src = u;
	};
	LLoader.prototype.createObjectURL = function(obj){
		var URL = window.URL || window.webkitURL;
		return URL.createObjectURL(obj);
	};
	LLoader.prototype.revokeObjectURL = function(src){
		var URL = window.URL || window.webkitURL;
		URL.revokeObjectURL(src);
	};
	return LLoader;
})();
/** @language chinese
 * 图片加载完成事件。
 * <p><a href="LEvent.html#property_COMPLETE">LEvent.COMPLETE</a></p>
 * @event LEvent.COMPLETE
 * @since 1.0.0
 */
/** @language chinese
 * 图片加载进度事件。
 * <p><a href="LEvent.html#property_PROGRESS">LEvent.PROGRESS</a></p>
 * @event LEvent.PROGRESS
 * @since 1.10.1
 */
/** @language chinese
 * 图片加载异常事件。
 * <p><a href="LEvent.html#property_ERROR">LEvent.ERROR</a></p>
 * @event LEvent.ERROR
 * @since 1.10.1
 */