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用仿ActionScript的语法来编写html5——第一篇,显示一张图片

 
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最近开始学习html5,因为一直都是研究as,所以还是觉得as顺眼一点,但是html5也不能不学,于是就想出了,可以把html5用as的语法来写出来,做游戏应该来的比较顺手一些,下面开始第一篇



第一篇,显示一张图片

一,代码对比

as代码:
public var loader:Loader;
public function loadimg():void{
	loader = new Loader();
	loader.contentLoaderInfo.addEventListener(Event.COMPLETE,complete);
	loader.load(new URLRequest("10594855.png"));
}
public function complete(event:Event):void{
	var image:Bitmap = Bitmap(loader.content);
	var bitmap:BitmapData = image.bitmapData;
	addChild(image);
}

js代码:
window.onload = function(){  
    var canvas = document.getElementById("myCanvas");  
    var context = canvas.getContext("2d");  
   
    image = new Image();  
    image.onload = function(){  
        context.drawImage(image, 0, 0, 240, 240);  
    };  
    image.src = "10594855.png";
};

二,编写js类库(暂命名为legend库)后的代码

var loader;
function main(){
	loader = new LLoader();
	loader.addEventListener(LEvent.COMPLETE,loadBitmapdata);
	loader.load("10594855.png","bitmapData");
}
function loadBitmapdata(event){
	var bitmapdata = new LBitmapData(loader.content);
	var bitmap = new LBitmap(bitmapdata);
	addChild(bitmap);
}

三,实现

1,建一个静态类,方便保存及访问公共的方法属性,比如canvas等

var LGlobal = function (){}
LGlobal.type = "LGlobal";

我们始终都用到canvas,所以要把canvas保存起来,给LGlobal类添加属性和方法
LGlobal.canvas = null;
LGlobal.width = 0;
LGlobal.height = 0;
LGlobal.setCanvas = function (id,width,height){
	var canvasObj = document.getElementById(id);
	if(width)canvasObj.width = width;
	if(height)canvasObj.height = height;
	LGlobal.width = canvasObj.width;
	LGlobal.height = canvasObj.height;
	LGlobal.canvas = canvasObj.getContext("2d");
} 

界面的显示,为了能够动态显示,选择不停的刷新canvas
给LGlobal类添加一个不停刷新的方法
LGlobal.onShow = function (){
	if(LGlobal.canvas == null)return;
	LGlobal.canvas.clearRect(0,0,LGlobal.width,LGlobal.height);
}

然后,我预想把所有现实的对象等都保存在一个数组里面,然后按照顺序显示
而所有可以显示的对象,都有一个show方法,用来把自己画到canvas上
LGlobal类最后修改为
var LGlobal = function (){}
LGlobal.type = "LGlobal";
LGlobal.canvas = null;
LGlobal.width = 0;
LGlobal.height = 0;
LGlobal.childList = new Array();
LGlobal.setCanvas = function (id,width,height){
	var canvasObj = document.getElementById(id);
	if(width)canvasObj.width = width;
	if(height)canvasObj.height = height;
	LGlobal.width = canvasObj.width;
	LGlobal.height = canvasObj.height;
	LGlobal.canvas = canvasObj.getContext("2d");
} 
LGlobal.onShow = function (){
	if(LGlobal.canvas == null)return;
	LGlobal.canvas.clearRect(0,0,LGlobal.width,LGlobal.height);
	LGlobal.show(LGlobal.childList);
}
LGlobal.show = function(showlist){
	var key;
	for(key in showlist){
		if(showlist[key].show){
			showlist[key].show();
		}
	}
}

2,as中,图片显示用到BitmapData和Bitmap两个类,为了实现这两个类的功能,我们分别创建两个类LBitmapData和LBitmap

先来看LBitmapData类,LBitmapData类用来储存图片的数据等,我们把Image()储存到LBitmapData类里面
function LBitmapData(image,x,y,width,height){
	var self = this;
	self.type = "LBitmapData";
	self.oncomplete = null;
	if(image){
		self.image = image;
		self.x = (x==null?0:x);  
		self.y = (y==null?0:y);  
		self.width = (width==null?self.image.width:width);  
		self.height = (height==null?self.image.height:height);
	}else{
		self.x = 0;  
		self.y = 0;  
		self.width = 0;  
		self.height = 0;
		self.image = new Image();
	}
}

在看LBitmap类,LBitmap类用来显示LBitmapData类里储存的Image()
function LBitmap(bitmapdata){
	var self = this;
	self.type = "LBitmap";
	self.x = 0;  
	self.y = 0;  
	self.width = 0;  
	self.height = 0;  
	self.scaleX=1;
	self.scaleY=1;
	self.visible=true;
	self.bitmapData = bitmapdata; 
	if(self.bitmapData){
		self.width = self.bitmapData.width;
		self.height = self.bitmapData.height;
	}
}

关于Image()的显示,我们用到一开始说的show方法,实现如下
LBitmap.prototype = {
	show:function (){
		var self = this;
		if(!self.visible)return;
		LGlobal.canvas.drawImage(self.bitmapData.image,
				self.bitmapData.x,self.bitmapData.y,self.bitmapData.width,self.bitmapData.height,
				self.x,self.y,self.width*self.scaleX,self.height*self.scaleY);
	}
}

3,最后,还差一个Loader,我们建立自己的LLoader类
function LLoader(){
	var self = this;
	self.loadtype = "";
	self.content = null;
	self.oncomplete = null;
	self.event = {};
}
LLoader.prototype = {
	addEventListener:function(type,listener){
		var self = this;
		if(type == LEvent.COMPLETE){
			self.oncomplete = listener;
		}
	},
	load:function (src,loadtype){
		var self = this;
		self.loadtype = loadtype;
		if(self.loadtype == "bitmapData"){
			self.content = new Image();
			self.content.onload = function(){
				if(self.oncomplete){
					self.event.currentTarget = self.content;
					self.oncomplete(self.event);
				}
			}
			self.content.src = src; 
		}
	}
}

4,在3里面用到了LEvent类,LEvent类是一个事件类,用来加载事件,点击等,这个以后再慢慢强化
var LEvent = function (){};
LEvent.COMPLETE = "complete";
LEvent.ENTER_FRAME = "enter_frame";


LEvent.currentTarget = null;
LEvent.addEventListener = function (node, type, fun){
	if(node.addEventListener){
		node.addEventListener(type, fun, false);
	}else if(node.attachEvent){
		node['e' + type + fun] = fun;
		node[type + fun] = function(){node['e' + type + fun]();}
		node.attachEvent('on' + type, node[type + fun]);
	}
}

5,在显示之前,我们需要有个addChild方法,如下
function addChild(DisplayObject){
	LGlobal.childList.push(DisplayObject);
}

6,最后,在整个页面读取完成后,就可以把图片显示出来了
function init(speed,canvasname,width,height,func){
	LEvent.addEventListener(window,"load",function(){
		setInterval(function(){LGlobal.onShow();}, speed);
		LGlobal.setCanvas(canvasname,width,height);
		func();
	});
}
init(40,"back",300,300,main);
var loader;
function main(){
	loader = new LLoader();
	loader.addEventListener(LEvent.COMPLETE,loadBitmapdata);
	loader.load("10594855.png","bitmapData");
}
function loadBitmapdata(event){
	var bitmapdata = new LBitmapData(loader.content);
	var bitmap = new LBitmap(bitmapdata);
	addChild(bitmap);
}


第一篇完成,下一篇,实现Sprite类

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