海报生成失败

<template>
  <div class="poster-share__content">
    <!-- canvas生成的海报图片 -->
    <img
      v-if="posterImg"
      class="poster-share__content--img"
      mode="aspectFit"
      :src="posterImg"
    >
    <!-- 分享海报canvas绘制部分 -->
    <canvas
      class="poster-share__content--cvs"
      :canvas-id="canvasId"
    ></canvas>
  </div>
</template>

.poster-share__content {
  position: absolute;
  right: -9999px;
  top: -9999px;
  width: 560px;
  height: 852px;
  opacity: 0;
  z-index: -1;

  &--img {
    width: 100%;
    height: 100%;
  }

  &--cvs {
    width: 100%;
    height: 100%;
  }
}

  name: 'CpPosterShare',
  model: {
    prop: 'value',
    event: 'update:value',
  },
  props: {
    value: {
      type: Boolean,
      default: false,
    },
    config: {
      type: Object,
      default: () => ({}),
    },
  },
  data () {
    return {
      isDraw: false, // 是否开始绘制海报
      posterImg: '', // 生成的海报图片地址
      canvasId: `canvasId${ Math.random() }`,
      screenWidth: null, // 屏幕宽度
    }
  },
  watch: {
    value: {
      handler (val) {
        this.isDraw = val
      },
      immediate: true,
    },
    isDraw (val) {
      this.$emit('update:value', val)
      if (val) {
        this.init()
      }
    },
  },

// 加载图片
loadImg (src) {
  return newPromise((resolve, reject) => {
    Taro.getImageInfo({
      src,
    }).then((res) => {
      resolve({ ...res })
    }).catch((err) => {
      reject(err)
    })
  })
}

const promiseParams = [this.loadImg(BgImage), this.loadImg(QRcode)]
const promiseAll = Promise.all(promiseParams.map((item) =>item.catch(() =>null)))

promiseAll.then((res) => {
  this.draw(res)
}).catch((err) => {
  console.log(err)
})

ctx.draw(false, () => {
  Taro.canvasToTempFilePath({
    canvasId:this.canvasId,
  }).then((res) => {
    this.posterImg = res.tempFilePath

    // 唤起分享菜单
    this.showShareImageMenu()
  }).catch((err) => {
    console.log('海报生成失败', err)
    Taro.showToast({
      title: '海报生成失败',
      icon: 'error',
    })
  }).finally(() => {
    Taro.hideLoading()
    this.isDraw = false
  })
})

showShareImageMenu () {
  if (Taro.showShareImageMenu) {
    Taro.showShareImageMenu({
      path:this.posterImg,
    }).then().catch((err) => {
      console.log(err)
      const { errMsg } = err
      // 取消操作  errMsg === 'showShareImageMenu:fail cancel'
      // 拒绝授权  errMsg: "showShareImageMenu:fail auth deny"
      if (errMsg === 'showShareImageMenu:fail auth deny') {
        authorize({
          scope:'writePhotosAlbum',
          showModal:true,
          authName:'保存图片到相册',
          success: () => {
            this.downloadImg()
          },
        })
      }
    }).finally(() => {
      this.isDraw = false
    })
  } else {
    Taro.showToast({
      title:'小程序版本不支持该功能',
      icon:'error',
    })
  }
}

/**
 * 权限获取流程
 * @param scope       权限英文名称
 * @param success     授权成功的回调
 * @param fail        授权失败的回调
 * @param showModal   授权失败是否展示对话框提示
 * @param authName    授权失败是否展示对话框提示展示的授权名称
 *  // 例子：开启用户的相册权限
    authorize({
      scope: 'writePhotosAlbum',
      showModal: true,
      authName: '保存图片到相册',
      success () {
        console.log('授权成功')
      },
    })
*/
export async function authorize (options) {
  const {
    scope, success, fail, showModal = false, authName = '',
  } = options
  try {
    const scopeName = `scope.${ scope }`
    const auth = await Taro.getSetting()
    if (!auth.authSetting[scopeName]) {
      Taro.authorize({ scope: scopeName }).then((res) => {
        if (res.errMsg === 'authorize:ok' && success) success()
      }, () => {
        if (showModal && authName) {
          Taro.showModal({
            title: '授权提示',
            content: `您拒绝了${ authName }权限，是否打开设置去授权？`,
          }).then((res) => {
            if (res.confirm) {
              Taro.openSetting().then((res2) => {
                if (res2.authSetting[scopeName] && success) {
                  success()
                } else if (fail) {
                  fail()
                }
              })
            } else {
              fail && fail()
            }
          }).catch((res) => {
            fail && fail(res)
          })
        } else {
          fail && fail()
        }
      })
    } else {
      success && success()
    }
  } catch (err) {
    fail && fail(err)
  }
}

<poster-share
  v-model="draw"  // 是否开始绘制海报海报
  config="config"  // 海报配置信息
/>