Edged arrows with tikz-qtree

Question

I've seen this nice little example tree drawn with LaTeX, afaik not tikz. Can I draw similar arrows with tikz-qtree by specifying start and end point only?

Answer 1

This isn't too hard to do with tikz-qtree. In order to get the movement arrow from T to C to go under the VP, I made the object DP a node and used that as a reference point to create an intermediate node that the line passes through. Thanks very much to both Peter Grill and percusse for suggesting elegant ways to avoid the VP structure. The final solution is due to percusse, who also provided the nifty code to have the one arrow jump over the other.

\documentclass{article}
\usepackage{tikz-qtree, tikz-qtree-compat}
\tikzset{every tree node/.style={align=center, anchor=north}}
\usetikzlibrary{positioning}
\usepackage{fixltx2e}
\newcommand*\sub{\textsubscript}
\begin{document}
\begin{tikzpicture}
\Tree [.CP  
        [.\node (DP) {DP};  \edge[roof];  {Die Kinder} ]
        [.C\1 
          [.\node (C) {C\\haben}; ] 
          [.TP [.\node (DPt1) {DP\\t\sub{i}}; ] 
            [.T\1 
              [.VP 
                [.VP [.\node (DPt2) {DP\\t\sub{i}}; ] 
                  [.V\1  
                    [.\node (Obj) {DP}; \edge[roof]; {diesen Film} ]  
                    [.V\\gesehen ] ] ] 
                [.\node (Aux) {V\\t\sub{j}}; ] ] 
            [.\node (T) {T\\t\sub{j}}; ]]]]]
\node (DPn) [below=1cm of DP] {};
\draw [->] (DPt1) -|  (DPn);
\draw [->] (DPt2) -| (DPt1);
\draw [->] (Aux.south) -| (T);
\draw [->] (T.east) |- ([yshift=-1.5cm] Obj.south) 
           -| ([yshift=-1.5mm]C |- DPt1) arc (-90:90:1.5mm) -- (C);
\end{tikzpicture}
\end{document}