HarmonyOS 目前如何截超长图

示例参考：

import componentSnapshot from '@ohos.arkui.componentSnapshot'
import image from '@ohos.multimedia.image'

@Entry
@Component
struct SnapshotTestPage {
  @State pixmap: image.PixelMap | undefined = undefined
  build() {
    Column() {
      Scroll() {
        Column() {
          Image($r('app.media.1111111')).width('100%').height('auto').id('image1')
          Image($r('app.media.1111111')).width('100%').height('auto').id('image2')
          Image($r('app.media.1111111')).width('100%').height('auto').id('image3')
          Image($r('app.media.1111111')).width('100%').height('auto').id('image4')
        }.width('100%').id('column')
      }.width('100%')
      .height('100%')
      .id('scroll')
      .onAreaChange((oldValue: Area, newValue: Area) => {
        console.info('组件宽高：' + vp2px(newValue.width as number).toString() + '，' +
        vp2px(newValue.height as number).toString())
      })

      Button("click to generate UI snapshot")
        .onClick(() => {

          componentSnapshot.get("scroll", (error: Error, pixmap: image.PixelMap) => {
            if (error) {
              console.log("error: " + JSON.stringify(error))
              return;
            }
            this.pixmap = pixmap
            this.pixmap.getImageInfo().then((imageInfo: image.ImageInfo) => {
              if (imageInfo == undefined) {
                console.error("Failed to obtain the image pixel map information.");
              }
              console.info('imageSize: ' + imageInfo.size.width.toString() + '，' + imageInfo.size.height.toString())
            })
          })
        }).margin(10)
        .position({ top: 100, left: 20 })
    }
    .width('100%')
    .height('100%')
    .alignItems(HorizontalAlign.Center)
  }
}