vue+element怎么实现图片上传及裁剪功能

npm install vue-cropper

import { VueCropper } from 'vue-cropper' 
components: {
 VueCropper,
},

<template>
  <div>
    <h2>图片上传</h2>
    <div>
      <el-upload
        class="avatar-uploader"
        action="https://jsonplaceholder.typicode.com/posts/"
        :show-file-list="false"
        :on-success="handleAvatarSuccess"
        :before-upload="beforeAvatarUpload"
      >
      <img v-if="imageUrl" :src="imageUrl" class="avatar">
      <i v-else class="el-icon-plus avatar-uploader-icon"></i>
      </el-upload>
    </div>
    <el-dialog title="图片剪裁" :visible.sync="dialogVisible" append-to-body>
      <div class="cropper-content">
        <div class="cropper" >
          <vueCropper
            ref="cropper"
            :img="option.img"
            :outputSize="option.outputSize"
            :outputType="option.outputType"
            :info="option.info"
            :canScale="option.canScale"
            :autoCrop="option.autoCrop"
            :autoCropWidth="option.autoCropWidth"
            :autoCropHeight="option.autoCropHeight"
            :fixed="option.fixed"
            :fixedBox="option.fixedBox"
            :fixedNumber="option.fixedNumber"
          ></vueCropper>
        </div>
      </div>
      <div slot="footer" class="dialog-footer">
        <el-button @click="dialogVisible = false">取 消</el-button>
        <el-button type="primary" @click="finish" :loading="loading">确认</el-button>
      </div>
    </el-dialog>
  </div>
</template>
<script>
import {VueCropper} from 'vue-cropper'
export default {
  components: {
    VueCropper
  },
  data(){
    return{
      imageUrl: '',
      dialogVisible: false,
      // 裁剪组件的基础配置option
      option: {
        img: '', // 裁剪图片的地址
        info: true, // 裁剪框的大小信息
        outputSize: 0.8, // 裁剪生成图片的质量
        outputType: 'jpeg', // 裁剪生成图片的格式
        canScale: false, // 图片是否允许滚轮缩放
        autoCrop: true, // 是否默认生成截图框
        autoCropWidth: 100, // 默认生成截图框宽度
        autoCropHeight: 100, // 默认生成截图框高度
        fixedBox: true, // 固定截图框大小 不允许改变
        fixed: true, // 是否开启截图框宽高固定比例
        fixedNumber: [1, 1], // 截图框的宽高比例
        full: true, // 是否输出原图比例的截图
        canMoveBox: false, // 截图框能否拖动
        original: false, // 上传图片按照原始比例渲染
        centerBox: false, // 截图框是否被限制在图片里面
        infoTrue: true, // true 为展示真实输出图片宽高 false 展示看到的截图框宽高
        canMove:true,
      },
      picsList: [], //页面显示的数组
      // 防止重复提交
      loading: false,
      fileinfo:{}
    }
  },
  methods: {
   handleAvatarSuccess(res, file,fileList) {
    //上传成功后将图片地址赋值给裁剪框显示图片
    this.$nextTick(() => {
      this.option.img = URL.createObjectURL(file.raw);
      this.fileinfo = res
      this.dialogVisible = true
    })
   },
   beforeAvatarUpload(file) {
    const isJPG = file.type === 'image/jpeg'||file.type==='image/png';
    const isLt2M = file.size / 1024 / 1024 < 2;
 
    if (!isJPG) {
     this.$message.error('上传头像图片只能是 JPG 格式!');
    }
    if (!isLt2M) {
     this.$message.error('上传头像图片大小不能超过 2MB!');
    }
    return isJPG && isLt2M;
   },
    finish() {
      this.$refs.cropper.getCropBlob((data) => {
        var fileName = 'goods' + this.fileinfo.uid
        this.loading = true
        //上传阿里云服务器
        //请求
      })
    }
  }
}
</script>
<style scoped>
  .avatar-uploader{
    background:red!important;
    width:150px;height:150px;
    text-align: center;
    line-height: 150px;
  }
  .el-icon-plus{
    width:150px;height:150px;font-size:30px;
  }
  .cropper-content{
    width:500px;height:500px;background: pink;
  }
  .cropper{
    width:500px;
    height:500px;
    background: yellow;
  }
</style>