1. 安装cropperjs依赖库

npm install cropperjs

2. 编写组件SimpleCropper.vue

<template>
  <div class="v-simple-cropper">
    <slot>
      <button @click="upload">上传图片</button>
    </slot>
    <input class="file" ref="file" type="file" accept="image/*" @change="uploadChange">
    <div class="v-cropper-layer" ref="layer">
      <div class="layer-header">
        <button class="cancel" @click="cancelHandle">取消</button>
        <button class="confirm" @click="confirmHandle">裁剪</button>
      </div>
      <img ref="cropperImg">
    </div>
  </div>
</template>

<script>
import Cropper from 'cropperjs'
import 'cropperjs/dist/cropper.min.css'
export default {
  name: 'v-simple-cropper',
  props: {
    initParam: Object,
    successCallback: {
      type: Function,
      default: () => {}
    }
  },
  data () {
    return {
      cropper: {},
      filename: ''
    }
  },
  mounted () {
    this.init()
  },
  methods: {
    // 初始化裁剪插件
    init () {
      let cropperImg = this.$refs['cropperImg']
      this.cropper = new Cropper(cropperImg, {
        aspectRatio: 1 / 1,
        dragMode: 'move'
      })
    },
    // 点击上传按钮
    upload () {
      this.$refs['file'].click()
    },
    // 选择上传文件
    uploadChange (e) {
      let file = e.target.files[0]
      this.filename = file['name']
      let URL = window.URL || window.webkitURL
      this.$refs['layer'].style.display = 'block'
      this.cropper.replace(URL.createObjectURL(file))
    },
    // 取消上传
    cancelHandle () {
      this.cropper.reset()
      this.$refs['layer'].style.display = 'none'
      this.$refs['file'].value = ''
    },
    // 确定上传
    confirmHandle () {
      let cropBox = this.cropper.getCropBoxData()
      let scale = this.initParam['scale'] || 1
      let cropCanvas = this.cropper.getCroppedCanvas({
        width: cropBox.width * scale,
        height: cropBox.height * scale
      })
      let imgData = cropCanvas.toDataURL('image/jpeg')
      let formData = new window.FormData()
      formData.append('fileType', this.initParam['fileType'])
      formData.append('img', imgData)
      formData.append('signId', this.$localStorage('signId'))
      formData.append('originalFilename', this.filename)
      window.$axios(this.initParam['uploadURL'], formData, {
        method: 'post',
        headers: {'Content-Type': 'multipart/form-data'}
      }).then(res => {
        this.successCallback(res.data)
        this.cancelHandle()
      })
    }
  }
}
</script>

<style lang="less">
.v-simple-cropper {
  .file {
    display: none;
  }
  .v-cropper-layer {
    position: fixed;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
    background: #fff;
    z-index: 99999;
    display: none;
    .layer-header {
      position: absolute;
      top: 0;
      left: 0;
      z-index: 99999;
      background: #fff;
      width: 100%;
      height: .8rem;
      padding: 0 .2rem;
      box-sizing: border-box;
    }
    .cancel,
    .confirm {
      line-height: .8rem;
      font-size: .28rem;
      background: inherit;
      border: 0;
      outline: 0;
      float: left;
    }
    .confirm {
      float: right;
    }
    img {
      position: inherit!important;
      border-radius: inherit!important;
      float: inherit!important;
    }
  }
}
</style>

3. 引用组件

<template>
  <simple-cropper :initParam="uploadParam" :successCallback="uploadHandle" ref="cropper">
    <img :src="userImg" @click="upload">
  </simple-cropper>
</template>

<script>
import SimpleCropper from '@/components/SimpleCropper'
export default {
  name: 'info',
  data () {
    return {
      uploadParam: {
        fileType: 'recruit', // 其他上传参数
        uploadURL: this.$dataURL + 'uploadAction/qcloudImg', // 上传地址
        scale: 4  // 相对手机屏幕放大的倍数: 4倍
      },
      userImg: this.$dataURL + 'test.png'
    }
  },
  methods: {
    // 上传头像
    upload () {
      this.$refs['cropper'].upload()
    },
    // 上传头像成功回调
    uploadHandle (data) {
      if (data.state === 'SUCCESS') {
        this.userImg = this.form.headImgUrl = data.fileId
      }
    }
  },
  components: {
    SimpleCropper
  }
}
</script>

4. 示例图