Egret里用矢量挖圆形的洞

 1 private createShape(): egret.Shape {
 2     let magicNum = 1 - 0.55228475;
 3     let radius = 100;
 4     let shape = new egret.Shape();
 5     shape.graphics.begin();
 6     shape.graphics.lineTo(radius, 0);
 7     shape.graphics.cubicCurveTo(magicNum * radius, 0, 0, magicNum * radius, 0, radius);
 8     shape.graphics.lineTo(0, 0);
 9     shape.graphics.endFill();
10     return shape;
11 }