HarmonyOS 如何实现线性控制字体背景颜色的透明度

colors使用rgba试试，请参考下方代码：

@Entry
@Component
struct Index {
  build() {

    Column(){
      Text("立即登录")
        .textAlign(TextAlign.Center)
        .fontColor(Color.White)
        .fontSize(12)
        .height(24)
        .textAlign(TextAlign.Center)
        .margin({ right: 10, })
        .alignRules({
          top: { anchor: "__container__", align: VerticalAlign.Top },
          bottom: { anchor: "__container__", align: VerticalAlign.Bottom },
          right: { anchor: "__container__", align: HorizontalAlign.End }
        })
        .borderRadius(50)
        .padding({
          top: 4,
          bottom: 4,
          left: 8,
          right: 8
        })
        .linearGradient({
          angle: 45,
          colors: [['rgba(149,137,244,1)', 0], ['rgba(149,137,244,0.66)', 0.33],['rgba(149,137,244,0.33)', 0.66],['rgba(149,137,244,0)', 1]]
        })
    }
  }
}