HarmonyOS 绘制圆滑折线或绘制曲线

drawing模块绘制贝塞尔曲线的例子可以参考以下案例：

import { RenderNode, DrawContext, FrameNode, NodeController } from "@ohos.arkui.node"
import drawing from "@ohos.graphics.drawing"

class TextRenderNode extends RenderNode {

  async draw(context: DrawContext) {
    const canvas = context.canvas;
    const pen = new drawing.Pen();
    pen.setStrokeWidth(5);
    pen.setColor({alpha: 255, red: 255, green: 0, blue: 0});
    let path = new drawing.Path();
    path.moveTo(200,200);
    path.cubicTo(250, 200, 250, 100, 300, 100);
    // path.moveTo(400,400);
    path.cubicTo(350,100,350,200,400,200)
    // path.close();
    canvas.attachPen(pen);
    canvas.drawPath(path);
    canvas.detachPen();
  }
}

class MyNodeController extends NodeController {
  private rootNode: FrameNode | null = null;
  private nodeArray: Array<TextRenderNode> = []
  addMyNode(item:TextRenderNode){
    this.nodeArray.push(item)
  }

  makeNode(uiContext: UIContext): FrameNode | null {
    this.rootNode = new FrameNode(uiContext);
    const renderNode = this.rootNode.getRenderNode();
    if (renderNode === null) {
      return this.rootNode;
    }
    if (renderNode) {
      renderNode.clearChildren()
      this.nodeArray.forEach((item) => {
        renderNode.appendChild(item)
      })
    }
    return this.rootNode;
  }
}

@Entry
@Component
struct Index {
  @State newNode:TextRenderNode = new TextRenderNode();
  @State nodeCV:MyNodeController = new MyNodeController()
  tempY = 0
  build() {
    Column() {
      Column() {
        NodeContainer(this.nodeCV)
          .width('100%')
          .height(200)
        Button('Invalidate')
          .onClick(() => {
            let newNode = new TextRenderNode()
            newNode.frame = { x: 0, y: this.tempY, width: 200, height: 100 }
            this.nodeCV.addMyNode(newNode)
            this.nodeCV.rebuild()
            this.tempY += 100
          })
      }
      .width('100%')
      .height('100%')
    }
    .height('100%')
  }
}

相关接口：https://developer.huawei.com/consumer/cn/doc/harmonyos-references-V5/js-apis-graphics-drawing-V5#cubicto

画虚线参考：https://developer.huawei.com/consumer/cn/doc/harmonyos-references-V5/ts-canvasrenderingcontext2d-V5#setlinedash