点击放大至全屏 再次点击缩小至原始  这个弹框是基于element dialog的基础上写的 

1.再utils文件夹下面新建一个directives.js  (封装好了 直接拿去用）

import Vue from 'vue';
import bigPic from '../assets/images/bigChange.png';
// v-dialogDrag: 弹窗拖拽属性
Vue.directive('dialogDrag', {
  bind(el, binding, vnode, oldVnode) {
    //弹框可拉伸最小宽高
    let minWidth = 400;

    let minHeight = 300;

    //初始非全屏

    let isFullScreen = false;

    //当前宽高

    let nowWidth = 0;

    let nowHight = 0;

    //当前顶部高度

    let nowMarginTop = 0;

    //获取弹框头部（这部分可双击全屏）

    const dialogHeaderEl = el.querySelector('.el-dialog__header');

    //弹窗

    const dragDom = el.querySelector('.el-dialog');

    // 全屏按钮

    dialogHeaderEl.insertAdjacentHTML('beforeEnd', '<div class="bigbtn"><div class="changeBig"></div><div class="changeSmall"></div></div>');

    const bigBtn = el.querySelector('.bigbtn');

    const changeBig = el.querySelector('.changeBig');

    const changeSmall = el.querySelector('.changeSmall');
    //给弹窗加上overflow auto；不然缩小时框内的标签可能超出dialog；

    dragDom.style.overflow = "auto";

    //清除选择头部文字效果

    //dialogHeaderEl.onselectstart = new Function("return false");

    //头部加上可拖动cursor

    dialogHeaderEl.style.cursor = 'move';

    // 获取原有属性 ie dom元素.currentStyle 火狐谷歌 window.getComputedStyle(dom元素, null);

    const sty = dragDom.currentStyle || window.getComputedStyle(dragDom, null);

    let moveDown = (e) => {
      // 鼠标按下，计算当前元素距离可视区的距离

      const disX = e.clientX - dialogHeaderEl.offsetLeft;

      const disY = e.clientY - dialogHeaderEl.offsetTop;

      // 获取到的值带px 正则匹配替换

      let styL, styT;

      // 注意在ie中 第一次获取到的值为组件自带50% 移动之后赋值为px

      if (sty.left.includes('%')) {

        styL = +document.body.clientWidth * (+sty.left.replace(/\%/g, '') / 100);

        styT = +document.body.clientHeight * (+sty.top.replace(/\%/g, '') / 100);

      } else {

        styL = +sty.left.replace(/\px/g, '');

        styT = +sty.top.replace(/\px/g, '');

      };

      document.onmousemove = function (e) {
        // 通过事件委托，计算移动的距离

        const l = e.clientX - disX;

        const t = e.clientY - disY;

        // 移动当前元素

        dragDom.style.left = `${l + styL}px`;

        dragDom.style.top = `${t + styT}px`;

        //将此时的位置传出去

        //binding.value({x:e.pageX,y:e.pageY})

      };

      document.onmouseup = function (e) {

        document.onmousemove = null;

        document.onmouseup = null;

      };

    }

    dialogHeaderEl.onmousedown = moveDown;

    //双击头部全屏效果

    bigBtn.onclick = (e) => {
      if (isFullScreen == false) {

        changeBig.style.display = 'none';

        changeSmall.style.display = 'block';

        nowHight = dragDom.clientHeight;

        nowWidth = dragDom.clientWidth;

        nowMarginTop = dragDom.style.marginTop;

        dragDom.style.left = 0;

        dragDom.style.top = 0;

        dragDom.style.height = "100VH";

        dragDom.style.width = "100VW";

        dragDom.style.marginTop = 0;

        isFullScreen = true;

        dialogHeaderEl.style.cursor = 'initial';

        dialogHeaderEl.onmousedown = null;

      } else {

        changeBig.style.display = 'block';

        changeSmall.style.display = 'none';

        dragDom.style.height = "auto";

        dragDom.style.width = nowWidth + 'px';

        dragDom.style.marginTop = nowMarginTop;

        isFullScreen = false;

        dialogHeaderEl.style.cursor = 'move';

        dialogHeaderEl.onmousedown = moveDown;

      }

    }

    dragDom.onmousemove = function (e) {
      // console.log(dialogHeaderEl,dragDom.querySelector('.el-dialog__body'), 123);
      let moveE = e;

      if (e.clientX > dragDom.offsetLeft + dragDom.clientWidth - 10 || dragDom.offsetLeft + 10 > e.clientX) {

        dragDom.style.cursor = 'w-resize';

      } else if (el.scrollTop + e.clientY > dragDom.offsetTop + dragDom.clientHeight - 10) {

        dragDom.style.cursor = 's-resize';

      } else {

        dragDom.style.cursor = 'default';

        dragDom.onmousedown = null;

      }

      dragDom.onmousedown = (e) => {

        const clientX = e.clientX;

        const clientY = e.clientY;

        let elW = dragDom.clientWidth;

        let elH = dragDom.clientHeight;

        let EloffsetLeft = dragDom.offsetLeft;

        let EloffsetTop = dragDom.offsetTop;

        dragDom.style.userSelect = 'none';

        let ELscrollTop = el.scrollTop;

        //判断点击的位置是不是为头部

        if (clientX > EloffsetLeft && clientX < EloffsetLeft + elW && clientY > EloffsetTop && clientY < EloffsetTop + 100) {

          //如果是头部在此就不做任何动作，以上有绑定dialogHeaderEl.onmousedown = moveDown;

        } else {

          document.onmousemove = function (e) {

            e.preventDefault(); // 移动时禁用默认事件

            //左侧鼠标拖拽位置

            if (clientX > EloffsetLeft && clientX < EloffsetLeft + 10) {

              //往左拖拽

              if (clientX > e.clientX) {

                dragDom.style.width = elW + (clientX - e.clientX) * 2 + 'px';

              }

              //往右拖拽

              if (clientX < e.clientX) {

                if (dragDom.clientWidth < minWidth) {

                } else {

                  dragDom.style.width = elW - (e.clientX - clientX) * 2 + 'px';

                }

              }

            }

            //右侧鼠标拖拽位置

            if (clientX > EloffsetLeft + elW - 10 && clientX < EloffsetLeft + elW) {

              //往左拖拽

              if (clientX > e.clientX) {

                if (dragDom.clientWidth < minWidth) {

                } else {

                  dragDom.style.width = elW - (clientX - e.clientX) * 2 + 'px';

                }

              }

              //往右拖拽

              if (clientX < e.clientX) {

                dragDom.style.width = elW + (e.clientX - clientX) * 2 + 'px';

              }

            }

            //底部鼠标拖拽位置

            if (ELscrollTop + clientY > EloffsetTop + elH - 20 && ELscrollTop + clientY < EloffsetTop + elH) {

              //往上拖拽

              if (clientY > e.clientY) {

                if (dragDom.clientHeight < minHeight) {

                } else {

                  dragDom.style.height = elH - (clientY - e.clientY) * 2 + 'px';

                }

              }

              //往下拖拽

              if (clientY < e.clientY) {

                dragDom.style.height = elH + (e.clientY - clientY) * 2 + 'px';

              }

            }

          };

          //拉伸结束

          document.onmouseup = function (e) {

            document.onmousemove = null;

            document.onmouseup = null;

          };

        }

      }

    }
  }
})

2.再main.js引入

import './utils/directives.js';

3.页面直接以自定义属性名进行使用  (  v-dialogDrag  )

<el-dialog
     v-dialogDrag
      title="用户信息"
      :visible.sync="dialogVisible"
      width="50%"
      :close-on-click-modal="false"
      :before-close="handleClose">
      <div>
        <el-table :data="phoneData" style="width: 100%">
          <el-table-column prop="fullName" label="姓名" width="100"></el-table-column>
          <el-table-column prop="sex" label="性别" width="80"></el-table-column>
          <el-table-column prop="idCard" label="身份证号" min-width="120" show-overflow-tooltip></el-table-column>
          <el-table-column prop="mobile" label="联系电话" width="150"></el-table-column>
          <el-table-column prop="censusAreaName" label="户籍区划" min-width="120" show-overflow-tooltip></el-table-column>
          <el-table-column prop="censusAddr" label="户籍地址" min-width="100" show-overflow-tooltip></el-table-column>
          <el-table-column label="操作" width="120" fixed="right" align="center">
            <template slot-scope="{row}">
              <span @click="chooseInfor(row.id)" class="table-btn">选择</span>
            </template>
          </el-table-column>
        </el-table>
      </div>
    </el-dialog>

4.CSS也一并奉上 （注意查看directives.js里面的标签元素）

.changeBig {
    width: 20px;
    height: 20px;
    background: url("../assets/images/bigChange.png") no-repeat center;
    background-size: 100% 100%;
    cursor: pointer;
    position: absolute;
    top: 14px;
    right: 60px;
}
.changeSmall {
    width: 20px;
    height: 20px;
    background: url("../assets/images/smallChange.png") no-repeat center;
    background-size: 100% 100%;
    cursor: pointer;
    position: absolute;
    top: 14px;
    right: 60px;
    display: none;
}