弹幕浮框
.overlay(this.overlayBuilder())
@Builder
overlayBuilder() {
Stack()
.height('100%')
.width('100%')
.linearGradient({ //渐变
direction: GradientDirection.Top, // 渐变方向
colors: [['#5e999595', 0.0], ['#ffa9a7a7', 0.23]]
})
.blendMode(BlendMode.DST_IN, BlendApplyType.OFFSCREEN)
.hitTestBehavior(HitTestMode.None)
}