actionscript-3 – 如何检测该区域是否100％绘制为as3

其中一种方法是 – 你制作一个屏蔽BitmapData,它具有透明度,并且在你需要你的玩家画画时是不透明的. (根据需要对其进行着色,但要确保颜色完全不透明).然后收集histogram()然后查询第255个值的alpha矢量,这将是填充零百分比的初始值.它们的范围为0-255,因此您不能使用100或任何其他固定值.然后,当玩家正在绘画时,您将画笔绘制在BitmapData上,并将blendMode参数设置为BlendMode.ERASE,这将净化您的BitmapData以获得绘制画笔的透明度.在播放器以任何方式完成绘制后(例如,绘画已用完),您在BitmapData上运行另一个直方图(),并查询Alpha通道矢量的第255个值. 0表示位图是完全透明的(或者至少只有少量像素保持不透明),因此您可以将零计为100％填充,对于任何更大的使用比例.

var bd:BitmapData=new BitmapData(w,h,true,0x0); // fully transparent initial bitmap
bd.draw(yourPaintBase); // a shape that designates area to be painted. Must be fully opaque
var bm:Bitmap=new Bitmap(bd);
// position it as needed,so the area which should be painted is aligned to wherever you need
addChild(bm);
addEventListener(Event.ENTER_FRAME,doPaint);
var baseValue:int=bd.histogram()[3][255]; // Vector #3 contains alpha,#255 contains 
// percentage of those pixels that have alpha of 255 = fully opaque
function doPaint(e:Event):void {
    if (!areWePainting) return;
    var sh:Shape=getBrush(); // shuold return an existing Shape object reference for performance
    sh.x=e.localX;
    sh.y=e.localY; // we are drawing where the mouse is
    bd.draw(sh,null,BlendMode.ERASE);
    decreasePaint(); // we have used some paint
    if (noMorePaint()) {
        e.target.removeEventListener(Event.ENTER_FRAME,doPaint);
        var endValue:int=Math.floor(100*(1-bd.histogram()[3][255]/baseValue));
        // aligning to percentage. This is the value you seek
        reportFilledPercentage(endValue);
    }
}