feature: add drag dialog (#477)

src/directive/el-dragDialog/drag.js

@@ -0,0 +1,46 @@
+export default{
+  bind(el, binding) {
+    const dialogHeaderEl = el.querySelector('.el-dialog__header')
+    const dragDom = el.querySelector('.el-dialog')
+    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)
+
+    dialogHeaderEl.onmousedown = (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
+      }
+    }
+  }
+}

src/directive/el-dragDialog/index.js

@@ -0,0 +1,13 @@
+import drag from './drag'
+
+const install = function(Vue) {
+  Vue.directive('el-drag-dialog', drag)
+}
+
+if (window.Vue) {
+  window['el-drag-dialog'] = drag
+  Vue.use(install); // eslint-disable-line
+}
+
+drag.install = install
+export default drag