[]这种进度条怎么实现?

import Sprite = Laya.Sprite



export default class Test extends Sprite{



	public DEF_SIZE: number = 200

	public CIRCLE_WIDTH: number = 20

	public $circleSprite: Sprite = new Sprite()

	public startY: number = -90





	constructor() {

		super()

		this._init()

	}



	private _init() {

		this.cacheAs = "bitmap"

		this.size(this.DEF_SIZE,this.DEF_SIZE)

		this.pos(200,200)

		this.cacheAs = "bitmap"

		this.graphics.drawPie(this.DEF_SIZE >> 1, this.DEF_SIZE >> 1, this.DEF_SIZE >> 1,-90,this.startY,'#ff0000')

		this.$circleSprite.blendMode = "destination-out"

		this.$circleSprite.pos(this.CIRCLE_WIDTH >> 1,this.CIRCLE_WIDTH >> 1)

		this.$circleSprite.graphics.clear()

		this.$circleSprite.graphics.drawCircle((this.DEF_SIZE - this.CIRCLE_WIDTH) >> 1, (this.DEF_SIZE - this.CIRCLE_WIDTH) >> 1, (this.DEF_SIZE - 20) >> 1, "#fff")

		this.addChild(this.$circleSprite)

		this.start()

	}





	public start() {

		this.timerLoop(2, this, this.draw)

	}



	public draw() {

		if (this.startY >= 270) {

			this.clearTimer(this, this.draw)

		}

		this.startY++

		this.graphics.clear()

		this.graphics.drawPie(this.DEF_SIZE >> 1, this.DEF_SIZE >> 1, this.DEF_SIZE >> 1,-90,this.startY,'#ff0000')

	}

}

Laya.stage.addChild(new Test())