安装

npm install vue-cropper
// 最好使用
npm install vue-cropper@0.3.6

如果使用vueCropper报错：Failed to mount component: template or render function not defined
原因是vue-cropper新版本报错，最方便的解决办法是将vue-cropper降到旧版本，我使用的是0.3.6。

npm uninstall vue-cropper
npm install vue-cropper@0.3.6

使用

main.js里面

import VueCropper from 'vue-cropper'
Vue.use(VueCropper)

组件内

1、两种上传按钮

<!-- element 上传图片按钮 -->
      <el-upload class="upload-demo" action="" drag 
:auto-upload="false" :show-file-list="false" :on-change='changeUpload'>
        <i class="el-icon-upload"></i>
        <div class="el-upload__text">点击上传</div>
        <div class="el-upload__tip">支持绝大多数图片格式，单张图片最大支持5MB</div>
      </el-upload>

使用element-ui的上传按钮，要配置:auto-upload="false"（不要自动上传）， :on-change='changeUpload'（选择完图片后的方法），一会儿再交代changeUpload方法

    <el-upload
        class="avatar-uploader"
        action=""
        :on-change="(file,filelist)=>onFileChange(file,filelist)"
        :show-file-list="false"
        :auto-upload="false"
        accept="image/*, .jpg, .png, .bmp"
      >
        <el-button type="primary" icon="el-icon-refresh-left">上传图片</el-button>
      </el-upload>

2、设置一个弹出层，放剪裁图片的cropper

 <!-- vueCropper 剪裁图片实现-->
    <el-dialog title="图片剪裁" :visible.sync="dialogVisible" append-to-body>
      <div class="cropper-content">
        <div class="cropper" style="text-align:center">
        <vueCropper
            ref="cropper"
            :img="option.img"
            :outputSize="option.size"
            :outputType="option.outputType"
            :info="true"
            :full="option.full"
            :canMove="option.canMove"
            :canMoveBox="option.canMoveBox"
            :original="option.original"
            :autoCrop="option.autoCrop"
            :fixed="option.fixed"
            :fixedNumber="option.fixedNumber"
            :centerBox="option.centerBox"
            :infoTrue="option.infoTrue"
            :fixedBox="option.fixedBox"
            @realTime="realTime"
          ></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>

或者

<el-dialog title="上传图片" :visible.sync="dialogVisible3" width="25%">
      <el-form :model="addForm">
        <div class="cropper-content" v-show="dialogVisible4">
          <div class="cropper" style="text-align:center">
            <vueCropper
              ref="cropper"
              :img="option.img"
              :autoCrop="true"
              :fixedNumber="[1, 1]"
              :fixed="true"
              :canScale="false"
              :outputType="'png'"
              :fixedBox="true"
              :outputSize='1'
              :maxImgSize='3000'
              :full="true"
            ></vueCropper>
          </div>
        </div>
      </el-form>
      <div slot="footer" class="dialog-footer">
        <el-upload
          class="avatar-uploader"
          action=""
          :on-change="(file,filelist)=>onFileChange(file,filelist)"
          :show-file-list="false"
          :auto-upload="false"
          accept="image/*, .jpg, .png, .bmp"
        >
          <el-button type="primary" icon="el-icon-refresh-left">上传图片</el-button>
        </el-upload>
        <el-button class="btnCus" icon="el-icon-check" @click="uploadImg" :loading="loadingImg">确认</el-button>
      </div>
    </el-dialog>

3、剪裁框的样式

// 截图
.cropper-content {
    .cropper {
        width: auto;
        height: 300px;
    }
}

4、方法
option是剪裁插件的属性配置，具体更多含义查看官网介绍，vue方式

<script>
import { client } from '@/utils/alioss'
export default {
  data() {
    return {
      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: 300, // 默认生成截图框宽度
        // autoCropHeight: 200, // 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: [7, 5], // 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
      },
      picsList: [],  //页面显示的数组
      // 防止重复提交
      loading: false
    }
  },
  methods: {
    // 上传按钮   限制图片大小
    changeUpload(file, fileList) {
      const isLt5M = file.size / 1024 / 1024 < 5
      if (!isLt5M) {
        this.$message.error('上传文件大小不能超过 5MB!')
        return false
      }
      this.fileinfo = file

      // 上传成功后将图片地址赋值给裁剪框显示图片
      this.$nextTick(() => {
        this.option.img = file.url
        this.dialogVisible = true
      })
    },
    // 点击裁剪，这一步是可以拿到处理后的地址
    finish() {
      this.$refs.cropper.getCropBlob((data) => {
        var fileName = 'goods' + this.fileinfo.uid
        this.loading = true
       //上传阿里云服务器
        client().put(fileName, data).then(result => {
          this.dialogVisible = false
          this.picsList.push(result.url)
        }).catch(err => {
          console.log(err)
          this.loading = false
        })
      })
    }
  }
}
</script>

使用typescript下

<script lang="ts">
import VueCropper from 'vue-cropper'
@Component({
    components: {
      VueCropper
    }
})
export default class CarManagePanel extends Vue {
  public fileinfo: any;
  public dialogVisible4: boolean = false;
  public option = {
    img: '', // 裁剪图片的地址
  }
  public addForm = {
    id: "",
    vehicleTypeName: "",
    imageUrl: "",
    file: "",
    attachmentName: ""
  };
  // 添加图片
  public onFileChange(e,list) {
    const isLt5M = e.size / 1024 / 1024 < 5
    if (!isLt5M) {
      this.$message.error('上传文件大小不能超过 5MB!')
      return false
    }
    this.fileinfo = e;
    let objectUrl = URL.createObjectURL(e.raw);
    // this.addForm.imageUrl = objectUrl;
    // this.addForm.file = e.raw;
    this.addForm.attachmentName = e.raw.name;
    // 上传成功后将图片地址赋值给裁剪框显示图片
    this.$nextTick(() => {
      this.option.img = objectUrl;
      this.dialogVisible4 = true;
    })
  }
// 上传图片
  public async uploadImg() {
    let files = {};
    let objectUrl = '';
    this.$refs.cropper.getCropBlob(data => {
      files = new window.File([data], this.addForm.attachmentName, {type: data.type});
      aliupload().upload(files, this.addForm.attachmentName).then(res=>{
        if (res.res.statusCode == '200') {
          this.addForm.imageUrl = res.res.requestUrls[0].split('?')[0];
          this.loadingImg = false;
          this.dialogVisible3 = false;
          this.showDelete = true;
        } else {
          this.loadingImg = false;
          this.$message.warning('上传图片失败!')
        }
      })
    })
  }
// 保存
  public saveForm() {
    if(this.addForm.id == ''){
      this.addVehicleType({
        vehicleTypeName: this.addForm.vehicleTypeName,
        vehicleImagePath: this.addForm.imageUrl
      }).then(res=>{
        this.addFormVisible = false;
        this.$message({ message: '添加成功', type: 'success' });
      })
    }else{
      this.editVehicleType({
        id: this.addForm.id,
        vehicleTypeName: this.addForm.vehicleTypeName,
        vehicleImagePath: this.addForm.imageUrl
      }).then(res=>{
        this.addFormVisible = false;
        this.$message({ message: '修改成功', type: 'success' });
      })
    }
    this.$emit("road");
  }
}
</script>