fix layout bug

src/core/layout.js

@@ -144,9 +144,10 @@ kity.extendClass(Minder, {
 
         root = root || this.getRoot();
 
+        // traverse without root
         root.traverse(function(node) {
             node.setLayoutTransform(null);
-        });
+        }, true);
 
         function layoutNode(node) {
 

src/core/node.js

@@ -113,11 +113,11 @@ var MinderNode = KityMinder.MinderNode = kity.createClass('MinderNode', {
      * 先序遍历当前节点树
      * @param  {Function} fn 遍历函数
      */
-    preTraverse: function(fn) {
+    preTraverse: function(fn, excludeThis) {
         var children = this.getChildren();
-        var value = fn(this);
+        if (!excludeThis) fn(this);
         for (var i = 0; i < children.length; i++) {
-            value = children[i].preTraverse(fn, value);
+            children[i].preTraverse(fn);
         }
     },
 
@@ -125,17 +125,16 @@ var MinderNode = KityMinder.MinderNode = kity.createClass('MinderNode', {
      * 后序遍历当前节点树
      * @param  {Function} fn 遍历函数
      */
-    postTraverse: function(fn) {
+    postTraverse: function(fn, excludeThis) {
         var children = this.getChildren();
-        var value;
         for (var i = 0; i < children.length; i++) {
-            value = children[i].postTraverse(fn, value);
+            children[i].postTraverse(fn);
         }
-        fn(this, value);
+        if (!excludeThis) fn(this);
     },
 
-    traverse: function(fn) {
-        return this.postTraverse(fn);
+    traverse: function(fn, excludeThis) {
+        return this.postTraverse(fn, excludeThis);
     },
 
     getChildren: function() {