拖动窗口指令 v-el-draggable-dialog

[theydy]

export const elDraggableDialog = {
  bind(el, _, vnode) {
    const dragDom = el.querySelector('.el-dialog');
    const dialogHeaderEl = el.querySelector('.el-dialog__header');
    dragDom.style.cssText += ';top:0px;';
    dialogHeaderEl.style.cssText += ';cursor:move;';

    dialogHeaderEl.onmousedown = (e) => {
      const disX = e.clientX - dialogHeaderEl.offsetLeft;
      const disY = e.clientY - dialogHeaderEl.offsetTop;

      const dragDomWidth = dragDom.offsetWidth;
      const dragDomHeight = dragDom.offsetHeight;

      const screenWidth = document.body.clientWidth;
      const screenHeight = document.body.clientHeight;

      const minDragDomLeft = dragDom.offsetLeft;
      const maxDragDomLeft = screenWidth - dragDom.offsetLeft - dragDomWidth;

      const minDragDomTop = dragDom.offsetTop;
      const maxDragDomTop = screenHeight - dragDom.offsetTop - dragDomHeight;

      const styleLeftStr = getComputedStyle(dragDom).left;
      const styleTopStr = getComputedStyle(dragDom).top;
      if (!styleLeftStr || !styleTopStr) return
      let styleLeft;
      let styleTop;

      // Format may be "##%" or "##px"
      if (styleLeftStr.includes('%')) {
        styleLeft = +document.body.clientWidth * (+styleLeftStr.replace(/%/g, '') / 100);
        styleTop = +document.body.clientHeight * (+styleTopStr.replace(/%/g, '') / 100);
      } else {
        styleLeft = +styleLeftStr.replace(/px/g, '');
        styleTop = +styleTopStr.replace(/px/g, '');
      }

      document.onmousemove = (e) => {
        let left = e.clientX - disX;
        let top = e.clientY - disY;

        // Handle edge cases
        if (-(left) > minDragDomLeft) {
          left = -minDragDomLeft;
        } else if (left > maxDragDomLeft) {
          left = maxDragDomLeft;
        }
        if (-(top) > minDragDomTop) {
          top = -minDragDomTop;
        } else if (top > maxDragDomTop) {
          top = maxDragDomTop;
        }

        // Move current element
        dragDom.style.cssText += `;left:${left + styleLeft}px;top:${top + styleTop}px;`;

        // Emit on-dialog-drag event
        // See https://stackoverflow.com/questions/49264426/vuejs-custom-directive-emit-event
        if (vnode.componentInstance) {
          vnode.componentInstance.$emit('on-dialog-drag');
        } else if (vnode.elm) {
          vnode.elm.dispatchEvent(new CustomEvent('on-dialog-drag'));
        }
      }

      document.onmouseup = () => {
        document.onmousemove = null;
        document.onmouseup = null;
      }
    }
  }
}

// Vue.directive('el-draggable-dialog', elDraggableDialog); // v-el-draggable-dialog