vue基于element dialog实现放大缩小拖拽功能

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1.在utils文件下新建一个drag.js 文件

import Vue from 'vue';
// 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.在main.js引入

import "./utils/drag.js"

3.页面直接以自定义属性名进行使用  (  v-dialogDrag  )

<el-dialog
  v-dialogDrag
  :title="dialogTitle"
  :visible.sync="dialogVisible"
  width="100%"
  :close-on-click-modal="false"
  :modal="false"
  append-to-body
  top="20vh"
>
</el-dialog>