[AS3]as3画笔实例实现橡皮擦功能源代码

    //主容器 
    var main:Sprite = new Sprite(); 
    main.mouseEnabled = false; 
    addChild(main) 
    //临时容器(所有操作都将先画在临时容器里,再进行"画"或"擦") 
    var mc:Sprite = new Sprite() 
    main.addChild(mc) 
    //保存最终画出来的内容的bitmapdata 
    var content:BitmapData = new BitmapData(550,400,true,0x00FFFFFF); 
    //把content显示出来 
    var show:Bitmap = new Bitmap(content) 
    main.addChildAt(show,0) 
     
    //默认选中画笔 
    var action:Number = 0 
    txt.text = "当前选中:画笔" 
     
     
    mc_move.addEventListener(MouseEvent.MOUSE_DOWN,startDraw) 
    a.addEventListener(MouseEvent.CLICK,changeAction) 
    b.addEventListener(MouseEvent.CLICK,changeAction) 
    function changeAction(e:MouseEvent):void 
    { 
        if(e.target.name == "a") 
        { 
            action = 0 
            txt.text = "当前选中:画笔" 
            mc.visible = true 
        }else 
        { 
            action = 1 
            txt.text = "当前选中:橡皮" 
            mc.visible = false 
        } 
    } 
    function startDraw(e:MouseEvent):void 
    { 
        mc.graphics.lineStyle(20,cp.selectedColor); 
        mc.graphics.moveTo(mouseX,mouseY); 
        mc_move.addEventListener(MouseEvent.MOUSE_MOVE,drawing); 
        stage.addEventListener(MouseEvent.MOUSE_UP,stopDraw); 
    } 
    function stopDraw(e:MouseEvent):void 
    { 
        if(action!=1)content.draw(mc,new Matrix(),new ColorTransform(),BlendMode.NORMAL,new Rectangle(0,0,550,400)) 
        mc.graphics.clear() 
        mc_move.removeEventListener(MouseEvent.MOUSE_MOVE,drawing); 
        stage.removeEventListener(MouseEvent.MOUSE_UP,stopDraw); 
    } 
    function drawing(e:MouseEvent):void 
    { 
        mc.graphics.lineTo(mouseX,mouseY) 
        if(action==1)content.draw(mc,new Matrix(),new ColorTransform(),BlendMode.ERASE) 
        e.updateAfterEvent() 
    }