uni-app自定义摄像头拍照添加人物框

<template>
  <view class="content" v-if="showHeader"
    style="position: fixed;top: 0;left: 0;z-index: 777;width: 100%;height: 100vh;background-color: #FFFFFF;">
    <camera :binderror="handleCameraError" :device-position="devicePosition" flash="off"
      style="width: 100%; height: 80vh;">
      <cover-image src="https://ucc.alicdn.com/images/user-upload-01/20210126152753150.png"
        style="width: 100%;height: 700rpx;margin-top:100rpx;"></cover-image>
    </camera>
    <view class="btns" style="width: 100%;height: 20vh;background: #3B4144;">
      <image class="item" @tap="chooseImage" src="../../static/write/photo.png"></image>
      <image class="item" @tap="takePhotoByHead" src="../../static/write/camare.png"></image>
      <image class="item" @tap="reverseCamera" src="../../static/write/change.png"></image>
    </view>
    <!-- <view class="error-handler" v-if="!authCamera">
      <button class="nobtn" openType="openSetting">打开相机授权</button>
    </view> -->
  </view>
</template>
<script>
  export default {
    data() {
      return {
        authCamera: false,
        showHeader: true,
        ctxHeader: null,
        devicePosition:'front'
      }
    }, 
    watch:{
      showHeader(val){
        console.log(val)
        return
        var that = this;
        //获取相机权限
        uni.getSetting({
          success(res) {
            console.log('相机权限:', res)
            if (res.authSetting["scope.camera"]) {
              that.authCamera = true
            } else {
              that.authCamera = false
              // uni.showModal({
              //  title: '权限申请',
              //  content: '需要摄像头权限，以拍摄照片。',
              //  success: (btn_res) => {
              //    if (btn_res.confirm) {
              //      uni.authorize({
              //        scope: 'scope.camera',
              //        success() {
              //          that.authCamera = true
              //        }
              //      })
              //    } else if (btn_res.cancel) {
              //    }
              //  }
              // });
            }
          }
        })
      }
    },
    onShow() {
      var that = this;
      //获取相机权限
      uni.getSetting({
        success(res) {
          console.log('相机权限:', res)
          if (res.authSetting["scope.camera"]) {
            that.authCamera = true
          } else {
            that.authCamera = false
            // uni.showModal({
            //  title: '权限申请',
            //  content: '需要摄像头权限，以拍摄照片。',
            //  success: (btn_res) => {
            //    if (btn_res.confirm) {
            //      uni.authorize({
            //        scope: 'scope.camera',
            //        success() {
            //          that.authCamera = true
            //        }
            //      })
            //    } else if (btn_res.cancel) {
            //    }
            //  }
            // });
          }
        }
      })
    },
    onLoad() {
      // console.log(window.innerHeight)
      // if (uni.createCameraContext) {
      //  setTimeout(() => {
      //    this.cameraContext = uni.createCameraContext();
      //  }, 200)
      // } else {
      //  // 如果希望用户在最新版本的客户端上体验您的小程序，可以这样子提示
      //  uni.showModal({
      //    title: '提示',
      //    content: '当前微信版本过低，无法使用该功能，请升级到最新微信版本后重试。'
      //  })
      // }
    },
    methods: {
      chooseImage(){
        uni.chooseImage({
            count: 1, //默认9
            sizeType: ['original', 'compressed'], //可以指定是原图还是压缩图，默认二者都有
            sourceType: ['album'], //从相册选择
            success: (res)=> {
            this.newPath = res.tempFilePaths[0]
            console.log(this.newPath)
            this.$store.commit('set_photo', this.newPath)
            uni.navigateBack({
                delta: 1
            });
            }
        });
      },
      //拍摄头像
      takePhotoByHead() {
        this.showHeader = true //开启拍照
        this.ctxHeader = uni.createCameraContext();
        this.ctxHeader.takePhoto({
          quality: 'high',
          success: (res) => {
            console.log(res)
            uni.compressImage({
              src: res.tempImagePath,
              quality: 90, //压缩比例
              success: ress => {
                this.newPath = ress.tempFilePath; //图片
                console.log(this.newPath)
                this.$store.commit('set_photo', this.newPath)
                uni.navigateBack({
                    delta: 1
                });
              }
            })
          }
        });
      },
      handleCameraError() {
        uni.showToast({
          title: '用户拒绝使用摄像头',
          icon: 'none'
        })
      },
      reverseCamera() {
        this.devicePosition = (("back" === this.devicePosition) ? "front" : "back")
      },
    }
  }
</script>
<style lang="scss" scoped>
  .content {
    display: flex;
    flex-direction: column;
    // align-items: center;
    justify-content: center;
    background: #fff;
    box-sizing: border-box;
    height: 100%;
    width: 100vw;
    .btns {
      display: flex;
      justify-content: space-around;
      align-items: center;
      .item {
        width: 100rpx;
        height: 100rpx;
      }
    }
  }
</style>