HarmonyOS 底部自定义tabbar凹凸弧度效果

参考如下demo：

import { CustomTabBar } from './CustomTabBar';
@Entry
@Component
struct Index {
  tabController: TabsController = new TabsController()
  @State currentIndex: number = 0;
  @Provide('pageInfos') pageInfos: NavPathStack = new NavPathStack()
  @Builder

  build() {
    Navigation(this.pageInfos) {
      Stack() {
        Flex({ direction: FlexDirection.Column }) {
          Tabs({
            barPosition: BarPosition.End, //底部导航
            index: this.currentIndex,
            controller: this.tabController
          }) {
            TabContent() {
              Text('首页')
            }

            TabContent() {
              Text('消息')
            }

            TabContent() {
              Text('服务')
            }

            TabContent() {
              Text('小慧')
            }

            TabContent() {
              Text('我的')
            }
          }
          .animationDuration(0) //去掉切换页面的动画
          .scrollable(false) //去掉左右滑动的效果
          .barHeight(0)
          .layoutWeight(1)
          .scrollable(false)
          .onChange((index: number) => {
            this.currentIndex = index
          })

          CustomTabBar({
            currentIndex: $currentIndex
          })
        }
      }.width('100%')
      .height('100%')
    }
    .hideTitleBar(true)
    .mode(NavigationMode.Stack)
  }
}

// CustomTabBar.ets


@Preview
@Component
export struct CustomTabBar {
  @Link currentIndex: number;
  @State subscriptStr: string = ''

  @Builder
  subscript() {
    Row() {
      Text(this.subscriptStr)
        .textAlign(TextAlign.Center)
        .width('100%')
        .fontColor(Color.White)
        .fontSize(12)
    }
    .position({ x: 10, y: -10 })
    .width(25)
    .height(20)
    .backgroundColor(Color.Red)
    .borderRadius(10)
  }

  build() {
    Flex({
      direction: FlexDirection.Row,
      alignItems: ItemAlign.Center,
      justifyContent: FlexAlign.SpaceAround
    }) {
      ForEach(TabsInfos, (item: tabInfo, index: number) => {
        Column() {
          if (index === 2) {
            Column({ space: 10 }){
              Column(){
                Image(item.icon)
                  .size({width: 60 , height: 45 })
                  .interpolation(ImageInterpolation.High)
              }
              .padding(2)
              .margin({top:-30})
              .backgroundColor(Color.Transparent)

              Text(item.title)
                .fontSize(16)
                .fontColor(this.currentIndex === index ? '#333333':Color.Blue)
            }
          } else {
            Column({ space: 5 }){
              Image(this.currentIndex === index ? item.iconSel : item.icon)
                .size({ width: 30, height: 30 })
              Text(item.title)
                .fontSize(16)
                .fontColor(this.currentIndex === index ? '#333333':Color.Blue)
            }
          }
        }
        .onClick(() => {
          this.currentIndex = index
        })
      }, (item: tabInfo) => JSON.stringify(item))
    }
    .padding({ top: 5, bottom: Number(AppStorage.get('bottomRectHeight')) })
    .backgroundColor(Color.White)
    .shadow({radius:10,color:"#fff8f5f5", offsetY: -13})
  }
}

//  constantData.ets
export interface tabInfo {
  icon: Resource
  iconSel: Resource
  title: string
}

export const TabsInfos: tabInfo[] = [
  {
    icon: $r('app.media.icon'),
    iconSel: $r('app.media.weathergrey'),
    title: '首页'
  },
  {
    icon: $r('app.media.startIcon'),
    iconSel: $r('app.media.startIcon'),
    title: '消息'
  },
  {
    icon: $r('app.media.service'),
    iconSel: $r('app.media.service'),
    title: '服务'
  },
  {
    icon: $r('app.media.icon'),
    iconSel: $r('app.media.icon'),
    title: '小慧'
  },
  {
    icon: $r('app.media.icon'),
    iconSel: $r('app.media.icon'),
    title: '我的'
  },
]
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