怎么实现text的背景图片随文本长度变化而伸缩，保持高度不变

Text(`${this.textStr}`) 
  .height(18) 
  .backgroundImage($r('app.media.blank')) 
  .backgroundImageSize({height: 18, width: '100%'})

@Entry 
@Component 
struct Test { 
  build() { 
    Column(){ 
      Text(`${this.textStr}`) 
        .height(18) 
        .background(this.createBackgroundImg(18)) 
    } 
  } 
  @Builder createBackgroundImg(height: number) { 
    Image($r('app.media.blank')) 
      .height(height) 
      .objectFit(ImageFit.Fill) 
      .width('100%') 
  } 
}