actionscript-3 - AS3 : How do I clear graphics in a specific pixel/area

Question

我知道你用 graphics.clear要清除所有图形但从舞台上清除图形，我想清除特定像素中或 x-y 值之间的图形，我该怎么做？

Answer 1

没有办法用图形来做到这一点。我刚试过，绘制透明形状不会产生洞，唉。

您应该将您拥有的图形转换为 Bitmap 实例并使用像素:

package
{
    import flash.geom.Matrix;
    import flash.geom.Rectangle;

    import flash.display.Sprite;
    import flash.display.Bitmap;
    import flash.display.BitmapData;
    import flash.display.DisplayObject;

    public class Holey extends Sprite
    {
        public function Holey() 
        {
            super();

            // Lets create some example graphics.
            graphics.beginFill(0x990000);
            graphics.drawCircle(200, 200, 100);
            graphics.endFill();

            // Convert into raster and make 1 pixel transparent.
            var aBit:Bitmap = rasterize(this);
            aBit.bitmapData.setPixel32(50, 50, 0x00000000);

            graphics.clear();
            addChild(aBit);
        }

        private function rasterize(source:DisplayObject):Bitmap
        {
            // Obtain bounds of the graphics.
            var aBounds:Rectangle = source.getBounds(source);

            // Create raster of appropriate size.
            var aRaster:BitmapData = new BitmapData(aBounds.width, aBounds.height, true, 0x00000000);

            // Make an offset to capture all the graphics.
            var aMatrix:Matrix = new Matrix;
            aMatrix.translate(-aBounds.left, -aBounds.top);

            aRaster.draw(source, aMatrix);
            return new Bitmap(aRaster);
        }
    }
}