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);
}