added helper

Author: tomnelson

jungrapht-visualization/src/main/java/org/jungrapht/visualization/spatial/rtree/RTree.java

@@ -57,6 +57,11 @@ public static <T> RTree<T> create() {
     return new RTree();
   }
 
+  // Add this method inside RTree.java
+  static <T> RTree<T> withRoot(Node<T> root) {
+    return new RTree<>(root);
+  }
+
   public static <T> RTree<T> addAll(
       RTree<T> rtree,
       SplitterContext<T> splitterContext,