nodeview: further optimization of node view

app/widget/nodeview/nodeview.cpp

@@ -147,14 +147,10 @@ void NodeView::SelectWithDependencies(QList<Node *> nodes)
 
 void NodeView::ItemsChanged()
 {
-  QList<QGraphicsItem*> items = scene_.items();
+  QHash<NodeEdge *, NodeViewEdge *>::const_iterator i;
 
-  foreach (QGraphicsItem* item, items) {
-    NodeViewEdge* edge = dynamic_cast<NodeViewEdge*>(item);
-
-    if (edge != nullptr) {
-      edge->Adjust();
-    }
+  for (i=scene_.edge_map().begin();i!=scene_.edge_map().end();i++) {
+    i.value()->Adjust();
   }
 }
 

app/widget/nodeview/nodeviewscene.cpp

@@ -47,6 +47,11 @@ const QHash<Node *, NodeViewItem *> &NodeViewScene::item_map() const
   return item_map_;
 }
 
+const QHash<NodeEdge *, NodeViewEdge *> &NodeViewScene::edge_map() const
+{
+  return edge_map_;
+}
+
 void NodeViewScene::AddNode(Node* node)
 {
   NodeViewItem* item = new NodeViewItem();

app/widget/nodeview/nodeviewscene.h

@@ -39,6 +39,7 @@ public:
   void SetGraph(NodeGraph* graph);
 
   const QHash<Node*, NodeViewItem*>& item_map() const;
+  const QHash<NodeEdge*, NodeViewEdge*>& edge_map() const;
 
 public slots:
   /**