这段代码是用Actionscript-2写的，有没有人能帮我把它翻译成AS-3？

Question

this.createEmptyMovieClip('mask_mc',0); 
bg_mc.setMask(mask_mc);
var contor:Number=0;

// function drawCircle draws a circle on mask_mc MovieClip of radius r and having center to mouse coordinates
function drawCircle(mask_mc:MovieClip):Void{
    var r:Number = 20;
    var xcenter:Number = _xmouse;
    var ycenter:Number = _ymouse;
    var A:Number = Math.tan(22.5 * Math.PI/180);
    var endx:Number;
    var endy:Number;
    var cx:Number;
    var cy:Number;

    mask_mc.beginFill(0x000000, 100);
    mask_mc.moveTo(xcenter+r, ycenter);
    for (var angle:Number = Math.PI/4; angle<=2*Math.PI; angle += Math.PI/4) {
       xend = r*Math.cos(angle);
       yend = r*Math.sin(angle);

       xbegin =xend + r* A *Math.cos((angle-Math.PI/2));
       ybegin =yend + r* A *Math.sin((angle-Math.PI/2));
       mask_mc.curveTo(xbegin+xcenter, ybegin+ycenter, xend+xcenter, yend+ycenter);
    }
    mask_mc.endFill();
}

// contor variable is used to hold if the mouse is pressed (contor is 1) or not (contor is 0)
this.onMouseDown=function(){
    drawCircle(mask_mc);
    contor=1;
}

// if the mouse is hold and moved then we draw a circle on the mask_mc
this.onMouseMove=this.onEnterFrame=function(){
    if (contor==1){
        drawCircle(mask_mc);
    }
}
this.onMouseUp=function(){
    contor=0;
}

Answer 1

var mask_mc:MovieClip = new MovieClip();
bg_mc.setMask(mask_mc);
var contor:Number=0;

// function drawCircle draws a circle on mask_mc MovieClip of radius r and having center to mouse coordinates
function drawCircle(mask_mc:MovieClip):void{
    var r:Number = 20;
    var xcenter:Number = mouseX;
    var ycenter:Number = mouseY;
    var A:Number = Math.tan(22.5 * Math.PI/180);
    var endx:Number;
    var endy:Number;
    var cx:Number;
    var cy:Number;

    mask_mc.graphics.beginFill(0x000000, 100);
    mask_mc.graphics.moveTo(xcenter+r, ycenter);
    for (var angle:Number = Math.PI/4; angle<=2*Math.PI; angle += Math.PI/4) {
       xend = r*Math.cos(angle);
       yend = r*Math.sin(angle);

       xbegin =xend + r* A *Math.cos((angle-Math.PI/2));
       ybegin =yend + r* A *Math.sin((angle-Math.PI/2));
       mask_mc.graphics.curveTo(xbegin+xcenter, ybegin+ycenter, xend+xcenter, yend+ycenter);
    }
    mask_mc.graphics.endFill();
}

// contor variable is used to hold if the mouse is pressed (contor is 1) or not (contor is 0)
addEventListener(MouseEvent.MOUSE_DOWN, mouseDown);
addEventListener(MouseEvent.MOUSE_MOVE, mouseMoved);
addEventListener(MouseEvent.MOUSE_UP, mouseUp);
function mouseDown(e:MouseEvent):void{
    drawCircle(mask_mc);
    contor=1;
}
function mouseMoved(e:MouseEvent):void{
    if (contor==1){
        drawCircle(mask_mc);
    }
}
function mouseUp(e:MouseEvent):void{
 contor=0;
}

看到翻译起来有多简单了吗？你应该先试着自己翻译，然后再发表你的尝试。

这只是您的代码片段的直接翻译。您将不得不删除事件侦听器，否则将会有内存泄漏。

Answer 2

这些链接可能对您有用：

AS2 to AS3 Migration Cheatsheet

ActionScript Migration Cookbook

Answer 3

好吧，有时候开始的最好的方法就是试着把它编译成-3，看看它在哪里爆炸了。一些代码可以正常工作，然后你可以在google中输入错误(或者如果你遇到问题，可以向SO提交特定的问题)。如果你不是很了解和理解其中的区别，那么这将比仅仅试图“翻译”它要容易得多。