HarmonyOS CanvasGradient四个参数设置渐变色的规则是什么，设置了不生效

CanvasGradient四个参数设置渐变色的规则是什么，设置了不是很明显。

private drawArea(): void {
    this.context.restore();
    this.context.beginPath();
    let path = new Path2D("M10 165 L10 47 L12.5 46 L14.5 46.5 L16.5 47.5 L18.5 46 L20.5 46 L22.5 46 L24.5 46 L26.5 45.5 L28.5 45.5 L30.5 44.5 L32.5 44 L34.5 45 L36.5 43.5 L38.5 43.5 L40.5 43.5 L42.5 43.5 L44.5 43.5 L46.5 43 L48.5 43 L50.5 43 L52.5 41.5 L54.5 40.5 L56.5 39 L58.5 36.5 L60.5 31.5 L62.5 35 L64.5 35.5 L66.5 35 L68.5 35 L70.5 34 L72.5 33 L74.5 32.5 L76.5 31.5 L78.5 31.5 L80.5 31 L83 29.5 L85 30 L87 31.5 L89 31 L91 29.5 L93 28.5 L95 32.5 L97 35 L99 37.5 L101 39 L103 40.5 L105 39 L107 41 L109 44.5 L111 44 L113 45 L115 43.5 L117 43.5 L119 43.5 L121 43.5 L123 43.5 L123 165 Z");
    let path2d = new Path2D();
    path2d.addPath(path)
    this.context.fillStyle = this.buildStrokeStyle();
    this.context.fill(path2d, 'evenodd')
  }
  private buildStrokeStyle(): CanvasGradient | string {
    let grad = this.context.createLinearGradient(10,47,10,80);
    grad.addColorStop(0, '#bce02e51');
    grad.addColorStop(1, '#b2e9d0d6');
    return grad;
  }