HarmonyOS 鸿蒙Next 如何把Colum布局绘制成一张图片并且保存到本地

import { componentSnapshot, display } from '@kit.ArkUI';
import { image } from '@kit.ImageKit';
import { fileIo as fs, fileUri } from '@kit.CoreFileKit';
import { photoAccessHelper } from '@kit.MediaLibraryKit';

@Entry
@Component
struct Page_241119085813097 {
  @State message: string = 'Hello World';
  @State pixmap: image.PixelMap | undefined = undefined

  build() {
    Column(){

     Column(){
       Text(this.message)
         .height('300px')
         .width('100%')
         .fontSize(20)

       .backgroundColor(Color.Gray)

       Text(this.message)
         .height('300px')
         .width('100%')
         .fontSize(20)
       .backgroundColor(Color.Blue)

       Text(this.message)
         .height('300px')
         .width('100%')
         .fontSize(20)
       .backgroundColor(Color.Pink)
     }.id("root")

      Button("将column保存到本地")
        .onClick(() =>{
          componentSnapshot.get("root", {scale : 1, waitUntilRenderFinished : true})
            .then((pixelMap: image.PixelMap) => {
              let fileName  = Date.now().toString()
              let imageFile = fs.openSync(getContext().tempDir+"/"+ fileName + ".jpg", fs.OpenMode.READ_WRITE|fs.OpenMode.CREATE)
              image.createImagePacker().packToFile(pixelMap, imageFile.fd, {
                format: "image/jpeg",
                quality: 100,
              }).then(async () =>{
                const context = getContext(this);
                let phAccessHelper = photoAccessHelper.getPhotoAccessHelper(context)
                let srcFileUri: Array<string> = [fileUri.getUriFromPath(getContext().tempDir+"/"+ fileName + ".jpg")]
                console.debug(`图片 uri is : ${JSON.stringify(srcFileUri)}`)
                let photoCreationConfigs: Array<photoAccessHelper.PhotoCreationConfig> = [
                  {
                    title: '保存图片',
                    fileNameExtension: 'jpg',
                    photoType: photoAccessHelper.PhotoType.IMAGE,
                  }
                ]
                let desFileUris: Array<string> = await phAccessHelper.showAssetsCreationDialog(srcFileUri, photoCreationConfigs)
                console.debug(`目标图片 uri is : ${JSON.stringify(desFileUris)}`)
                if (desFileUris.length > 0) {
                  //文件拷贝
                  for (let index = 0; index < desFileUris.length; index++) {
                    let srcFile = fs.openSync(srcFileUri[index], fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE)
                    let destFile = fs.openSync(desFileUris[index], fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE)
                    fs.copyFileSync(srcFile.fd,destFile.fd)
                    fs.closeSync(srcFile);
                    fs.closeSync(destFile);
                  }
                } else {
                  console.log("11")
                }

                fs.closeSync(imageFile);
              })
              this.pixmap = pixelMap

              pixelMap.release(); // PixelMap使用完后及时释放内存

            }).catch((err:Error) => {
            console.log("error: " + err)
          })
        }).width("100%")
    }
    .height('100%')
    .width('100%')
  }
}