Fix：修复节点前后自定义内容导出图片时显示空白的问题

simple-mind-map/src/core/render/node/Node.js

@@ -11,7 +11,8 @@ import { CONSTANTS } from '../../../constants/constant'
 import {
   copyNodeTree,
   createForeignObjectNode,
-  createUid
+  createUid,
+  addXmlns
 } from '../../../utils/index'
 
 //  节点类
@@ -204,10 +205,7 @@ class Node {
     }
     // 如果没有返回内容，那么还是使用内置的节点内容
     if (this._customNodeContent) {
-      this._customNodeContent.setAttribute(
+      addXmlns(this._customNodeContent)
-        'xmlns',
-        'http://www.w3.org/1999/xhtml'
-      )
       return
     }
     this._imgData = this.createImgNode()
@@ -220,9 +218,15 @@ class Node {
     this._prefixData = createNodePrefixContent
       ? createNodePrefixContent(this)
       : null
+    if (this._prefixData && this._prefixData.el) {
+      addXmlns(this._prefixData.el)
+    }
     this._postfixData = createNodePostfixContent
       ? createNodePostfixContent(this)
       : null
+    if (this._postfixData && this._postfixData.el) {
+      addXmlns(this._postfixData.el)
+    }
   }
 
   //  计算节点的宽高

simple-mind-map/src/core/render/node/nodeCreateContents.js

@@ -5,7 +5,8 @@ import {
   addHtmlStyle,
   checkIsRichText,
   isUndef,
-  createForeignObjectNode
+  createForeignObjectNode,
+  addXmlns
 } from '../../../utils'
 import { Image as SVGImage, SVG, A, G, Rect, Text } from '@svgdotjs/svg.js'
 import iconsSvg from '../../../svg/icons'
@@ -157,7 +158,7 @@ function createRichTextNode() {
   div.innerHTML = html
   let el = div.children[0]
   el.classList.add('smm-richtext-node-wrap')
-  el.setAttribute('xmlns', 'http://www.w3.org/1999/xhtml')
+  addXmlns(el)
   el.style.maxWidth = textAutoWrapWidth + 'px'
   let { width, height } = el.getBoundingClientRect()
   // 如果文本为空，那么需要计算一个默认高度

simple-mind-map/src/utils/index.js

@@ -1335,7 +1335,7 @@ export const handleGetSvgDataExtraContent = ({
       if (!res) return
       const { el, cssText, height } = res
       if (el instanceof HTMLElement) {
-        el.setAttribute('xmlns', 'http://www.w3.org/1999/xhtml')
+        addXmlns(el)
         const foreignObject = createForeignObjectNode({ el, height })
         callback(foreignObject, height)
       }
@@ -1525,3 +1525,8 @@ export const defenseXSS = text => {
   // 返回最终结果
   return result
 }
+
+// 给节点添加命名空间
+export const addXmlns = el => {
+  el.setAttribute('xmlns', 'http://www.w3.org/1999/xhtml')
+}