HarmonyOS 按钮或其他控件背景色的渐变方案

@Entry  
@Component  
struct BlendModeDemo1 {  
  build() {  
    Column(){  
      Button('test')  
        .width(200)  
        .height(50)  
        .backgroundColor('#00000000')  
        .linearGradient({  
          angle: 90,  
          colors: [[0xff0000, 0.0], [0x0000ff, 0.3], [0xffff00, 1.0]]  
        })  
    }  
  }  
}