treeeeeeeeees

Author: Arne Böckmann

tutorials/tutorial_basic_envire_treeview.md

@@ -11,20 +11,14 @@ vertex_descriptors can be hashed in constant time (they are just pointers).
 
 ## Creating Tree Views
 TreeViews can be created by calling ``getTree()`` and providing a root node.
+<pre><code data-snippetId="graph_trees_get_1" data-file="https://raw.githubusercontent.com/envire/envire-tutorials/master/src/envire_graph_tutorials/trees.cpp"></code></pre>
 
-```cpp
-EnvireGraph g;
-const FrameId a = "frame_a";
-/* ... */
-TreeView view = g.getTree(graph.vertex(a));
-```
 Note that the view will most likely be copied on return. If the tree is large
 you might want to avoid that copy and pass an empty view as out-parameter instead:
+<pre><code data-snippetId="graph_trees_get_2" data-file="https://raw.githubusercontent.com/envire/envire-tutorials/master/src/envire_graph_tutorials/trees.cpp"></code></pre>
 
-```cpp
-EnvireGraph g;
-const FrameId a = "frame_a";
-/* ... */
-TreeView view;
-g.getTree(a, &view);
-```
+By default, a tree view shows a snapshot of the graph. I.e. if the graph changes,
+the changes will not be visible in the view. The view or parts of it might
+become invalid when vertices or edges are removed from the graph.
+To avoid this, you can request a self-updating tree view:
+<pre><code data-snippetId="graph_trees_get_3" data-file="https://raw.githubusercontent.com/envire/envire-tutorials/master/src/envire_graph_tutorials/trees.cpp"></code></pre>