vue中关于element的el-image 图片预览功能增加一个下载按钮(操作方法)

npm i element-ui -S

import ElementUI from 'element-ui'
import 'element-ui/lib/theme-chalk/index.css'
 
Vue.use(ElementUI)

<template>
<div style="margin-top: 2vh">
         <waterfall
             @loadmore="loadmore"
             :col=4
             :lazy-distance="300"
             :load-distance="300"
             :data="xx">
           <div class="cell-item zxzx demo-image__preview "  v-for="(item,index) in xx" :key="index" @click="checkImage" style="padding: 0 1vw;">
             <el-image
                 style="width: 100%; margin-top: 2vh"
                 :src="item.img1"
                 :preview-src-list="[item.img]">
             </el-image>
             <p style="background-color: rgba(0,0,0,0.1); color: #fff; text-align: center;  margin-top: -6px;">{{item.createTime}}</p>
           </div>
         </waterfall>
       </div>
</template>
 
<script>
 mounted() {
window.cl = this.cl
},
methods: {
cl() {
      let srcUrl=document.querySelector('.el-image-viewer__img').src;
      this.downloadIamge(srcUrl,srcUrl)
    },
 checkImage(){//这个事件要绑定el-image父级盒子上
      console.log('点击事件');
      let a=document.querySelector('.el-image-viewer__actions__inner');
      // $(a).append(`<i class="el-icon-download" onclick="installImage()"></i>`)
      // a.append( `<i class="el-icon-download" onclick="cl()"></i>`)
      console.log(a)
      let ff = document.createElement('i')
      ff.innerHTML = `<i class="el-icon-download" onclick="cl()"></i>`
      a.appendChild(ff)
    },
    downloadIamge(imgsrc, name) {//下载图片地址和图片名
      let image = new Image();
      // 解决跨域 Canvas 污染问题
      image.setAttribute("crossOrigin", "anonymous");
      image.onload = function() {
        let canvas = document.createElement("canvas");
        canvas.width = image.width;
        canvas.height = image.height;
        let context = canvas.getContext("2d");
        context.drawImage(image, 0, 0, image.width, image.height);
        let url = canvas.toDataURL("image/png"); //得到图片的base64编码数据
        let a = document.createElement("a"); // 生成一个a元素
        let event = new MouseEvent("click"); // 创建一个单击事件
        a.download = name || "photo"; // 设置图片名称
        a.href = url; // 将生成的URL设置为a.href属性
        a.dispatchEvent(event); // 触发a的单击事件
      };
      image.src = imgsrc;
    },
}
</script>