Egret 纹理、计时器

1. 九宫切

　　典型例子就是圆角矩形的拉伸问题。

　　先去P一张绿色的圆角矩形。

    private createGameScene():void {
        var box:egret.Bitmap = new egret.Bitmap();
        box.texture = RES.getRes("box_png");
        //拉伸
        box.width *= 2;     //矢量绘图是 Shape/Sprite 的 graphics 有的功能，才有自身的 width/height 与 所绘图形的 width/height
        this.addChild(box);

        var box9:egret.Bitmap = new egret.Bitmap(RES.getRes("box_png"));
        var rect9:egret.Rectangle = new egret.Rectangle(40, 40, 80, 80);
        box9.scale9Grid = rect9;
        box9.width *= 2;
        box9.y = 200;
        this.addChild(box9);
    }

　　看下两者的区别：

2. 纹理集

• 不用每次为一张图片执行一次HTTP请求；
• 引擎渲染时减少IO的次数；

　　主要是在配置与资源调用上进行微调即可：

• 合图并生成 json 配置文件；
• 资源类型为 sheet: {"name":"dogs","type":"sheet","url":"assets/dogs.json"}
• 调用时：RES.getRes( "dogs.dog1" )

 3. Timer

class myTimer extends egret.DisplayObjectContainer
{
    public constructor()
    {
        super();
        var timer:egret.Timer = new egret.Timer(500, 5);    //500ms执行1次，一共执行5次
        timer.addEventListener(egret.TimerEvent.TIMER, ()=>{
            myTimer.count ++;
            console.log("count:" + myTimer.count);
        }, this);
        timer.addEventListener(egret.TimerEvent.TIMER_COMPLETE, ()=>{ console.log("end")}, this);
        timer.start();
    }

    public static count:number = 0;
}

4. Tick： 

    private createGameScene():void {
        var heroTicks = new startTickerTest();

        //要添加到舞台才会触发 egret.Event.ADDED_TO_STAGE 事件，但 Main 这个容器是由 egret 自己添加到舞台的，看不到 addChild
        this.addChild(heroTicks);
    }

class startTickerTest extends egret.DisplayObjectContainer {
    public constructor() {
        super();

        //容器被添加到舞台显示列表时调用
        this.once(egret.Event.ADDED_TO_STAGE, this.onLoad, this);
    }

    private hero:egret.Bitmap;
    private speed:number = 0.05;
    private time:number = 0;

    private onLoad(event:egret.Event) {
        var hero:egret.Bitmap = new egret.Bitmap(RES.getRes("hero1_png"));
        this.addChild(hero);
        this.hero = hero;
        this.time = egret.getTimer();
        //不与帧率挂钩的每秒60次回调
        egret.startTick(this.moveStar, this);
    }

    //egret 在执行 startTick 的回调时，会给予参数 timeStamp(当前时间戳)
    private moveStar(timeStamp:number):boolean {
        var now = timeStamp;
        var time = this.time;
        var pass = now - time;   //平均时间间隔=1000ms/60=16.67ms
        console.log("moveStar: ",(1000 / pass).toFixed(5));
        this.hero.x += this.speed * pass;
        if(this.hero.x >= 300)
            egret.stopTick(this.moveStar, this);
        this.time = now;
        return false;
    }
}

5. 帧事件：

    private createGameScene():void {
        var heroTicks = new startTickerTest();
        this.addChild(heroTicks);
    }

class startTickerTest extends egret.DisplayObjectContainer {
    public constructor() {
        super();
        this.once(egret.Event.ADDED_TO_STAGE,this.onLoad,this);
    }

    private hero:egret.Bitmap;
    private timeOnEnterFrame:number = 0;
    private speed:number = 0.5;

    private onLoad(event:egret.Event) {
        var hero:egret.Bitmap = new egret.Bitmap(RES.getRes("hero1_png"));
        this.addChild(hero);
        this.hero = hero;
        //监听帧事件
 this.addEventListener(egret.Event.ENTER_FRAME,this.onEnterFrame,this); 
        this.timeOnEnterFrame = egret.getTimer();
    }

    private  onEnterFrame(e:egret.Event){
        var now = egret.getTimer();
        var time = this.timeOnEnterFrame;
        var pass = now - time;
        console.log("onEnterFrame: ", (1000 / pass).toFixed(5));
        this.hero.x += this.speed * pass;
        if(this.hero.x > 300)
            this.removeEventListener(egret.Event.ENTER_FRAME,this.onEnterFrame,this);
        this.timeOnEnterFrame = egret.getTimer();
    }
}

　　基础构成看的差不多了，剩下的知识在实际项目应用中边学边用了！