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Egret 矢量绘图、遮罩、碰撞检测

矢量绘图:

1. 为矢量绘图绘制外边 - graphics.lineStype()

    private createGameScene():void     {           console.log("Runtime start.");                var myShape:egret.Shape = new egret.Shape();                myShape.graphics.lineStyle(10, 0x00ff00, 1);        myShape.graphics.beginFill(0xff0000, 1);        myShape.graphics.drawRect(0,0,100,200);        myShape.graphics.endFill();        this.addChild(myShape);        console.log("Runtime end.");    }

2. 清空一个显示对象的绘图 - graphics.clear()

3. 绘制圆形 - graphics.drawCircle(0, 0, 50)

4. 画直线:

    private createGameScene():void     {                  var myShape:egret.Shape = new egret.Shape();          myShape.graphics.lineStyle(5, 0x00ff00, 1);        myShape.graphics.moveTo(50, 10);    //将画笔移动到起点位置        myShape.graphics.lineTo(100, 20);   //从起点位置划线到终点        myShape.graphics.endFill();        this.addChild(myShape);    }

5. 贝塞尔曲线:

    private createGameScene():void     {                  var myShape:egret.Shape = new egret.Shape();          myShape.graphics.lineStyle(5, 0x00ff00, 1);        myShape.graphics.moveTo(50, 200);           //将画笔移动到起点位置        myShape.graphics.curveTo(150, 50, 250, 200);   //指定起始移动方向的交汇点坐标,与终点坐标后进行画线        myShape.graphics.endFill();        this.addChild(myShape);    }

6. 绘制圆弧:

    private createGameScene():void     {                  var myShape:egret.Shape = new egret.Shape();          myShape.graphics.lineStyle(5, 0x00ff00, 1);        myShape.graphics.beginFill(0x1122cc);    
//圆心坐标、半径、起始弧度、终止弧度,填充的区域是圆弧+圆弧两端点的连接所包含的区域 myShape.graphics.drawArc(200,200,100,Math.PI/3, Math.PI); myShape.graphics.endFill(); this.addChild(myShape); }

7. 值得注意的是:graphic 可以用来绘制多个图形,不用一个 graphic 对应一个图形。

 

遮罩

1. 矩形遮罩:

    private createGameScene():void     {                  var shp: egret.Shape = new egret.Shape();        shp.graphics.beginFill(0xff0000);        shp.graphics.drawRect(0,0,100,100);        shp.graphics.endFill();        this.addChild(shp);                var shp2: egret.Shape = new egret.Shape();        shp2.graphics.beginFill(0x00ff00);        shp2.graphics.drawCircle(0,0,20);        shp2.graphics.endFill();        this.addChild(shp2);        shp2.x = 20;        shp2.y = 20;                  var rect: egret.Rectangle = new egret.Rectangle(20,20,30,50);   //参数指定的区域是遮罩不遮挡的区域        shp.mask = rect;    }

2. 对象遮罩:可以用一个对象当成另一个对象的遮罩

square.mask = circle;    //像这样直接指定即可

 

碰撞检测

    private createGameScene():void {        var infoTest = new egret.TextField();        infoTest.y = 200;        infoTest.text = "碰撞结果";                                                                                                     this.addChild(infoTest);      //显示一个文本以展示测试结果        var shp:egret.Shape = new egret.Shape();        shp.graphics.beginFill(0xff0000);        shp.graphics.drawRect(0, 0, 120, 120);                                                                                                         shp.graphics.endFill();        this.addChild(shp);                             console.log(shp.width);     //shp 的 width 与 height 与显示对线的内容相关,这里是 120        console.log(shp.height);           var testPoint = new egret.Shape();        testPoint.graphics.beginFill(0x000000);        testPoint.graphics.drawRect(100, 100, 5, 5);    //标记一个黑色的边界点        testPoint.graphics.endFill();        this.addChild(testPoint);                  var isHit:boolean = shp.hitTestPoint(110, 110); //结论:是否碰撞与 shp.graphics 相关,而与 shp.width/height 无关        infoTest.text = "碰撞结果" + isHit;              //就算已经 addchild,可以直接修改文本, 结果是 true                shp.graphics.clear();                           //如果不clear, 重新 drawRect 不会生效        shp.graphics.beginFill(0xff0000);        shp.graphics.drawRect(0, 0, 100, 100);                                                                                                         shp.graphics.endFill();            var isHit:boolean = shp.hitTestPoint(110, 110);         infoTest.text = "碰撞结果" + isHit;              //结果是 false                                                                                       }

  值得注意的是,精确坐标的碰撞检测是非常消耗性能的,尽量少用。

 

Egret 矢量绘图、遮罩、碰撞检测