How to create a bent arrow at a rectangle corner?

Question

I have created a rectangle and just can't find the solution how to draw a bent arrow from the south side (close to the south east corner) to the east side (also close to the south east corner).

\documentclass[12pt,twoside,a4paper]{report}     
\usepackage{a4} 
\usepackage{tikz} 
\usetikzlibrary{calc,decorations.markings,arrows,backgrounds,calendar,matrix,mindmap,patterns,shadows,trees,positioning}

\begin{document} 

\begin{tikzpicture}[auto, node distance=1cm,
    block_small/.style ={rectangle, draw=black, thick, fill=white, text centered, text width=4em, minimum height=4em}]  

\node [block_small, xshift=-3.3cm] (A) {A} ;
\node [block_small,right of=A, xshift=3.3cm] (B) {B} ; 

\begin{pgfonlayer}{background} 

   % Rectangle             
    \path (A.west |- A.north)+(-0.45,0.45) node (a) {};
    \path (B.south -| B.east)+(0.45,-0.45) node (b) {};
    \path[draw=black!50, dashed] (a) rectangle (b);

\end{pgfonlayer} 

\end{tikzpicture}  
\end{document}

I have spent already too much time on this and hope someone may help!

Welcome to TeX.SX! You can have a look at our starter guide to familiarize yourself further with our format. — Benedikt Bauer, Nov 07 '13 at 09:56
That looks like a job for Qrrbrbirlbel's paths.ortho library. — Jake, Nov 07 '13 at 10:00
The arc is expecting arc (start angle:end angle:radius), so for the other corner it would be arc (-180:90:0.5). If you would do arc (180:90:0.5) it would just draw a qurter circle clockwise. If you don't like negative angles, you can also specify angles larger than 360 degree, so arc (180:450:0.5) would also work. — Tom Bombadil, Nov 07 '13 at 12:47

Tom Bombadil · Answer 1 · 2013-11-07T12:41:29.447

You can construct the box easier with the fit library. Just put fit=(a1)(a2)...(an) into the options of a new node, with inner sep=<length> you can control the distance to all the fitted nodes.
The calc library lets you do things like ($(a)+(0,1)$) which is the position 1 unit up from node a. With that you can do things like "from the south side (close to the south east corner)"
for a bent arrow, you can use the to[out=<deg>,in=<deg>,looseness=<val>] operation. If you dont like this arrow, you can also specify more intermediate points. If the arrow starts and ends at the same distance from the corner, you can also use an arc. Arcs are specified via arc (start angle:end angle:radius)

Code

\documentclass[12pt,twoside,a4paper]{report} 
\usepackage{tikz}
\usetikzlibrary{calc,fit,arrows}

\begin{document} 

\begin{tikzpicture}
[   auto, node distance=1cm,
  block_small/.style ={rectangle, draw=black, thick, fill=white, text centered, text width=4em, minimum height=4em}
]
    \node [block_small, xshift=-3.3cm] (A) {A} ;
    \node [block_small,right of=A, xshift=3.3cm] (B) {B} ; 

    % Rectangle             
    \node[fit=(A)(B),dashed,draw,inner sep=0.45cm] (Box) {};

    \draw[-stealth] ($(Box.south east)+(-0.5,0)$) to[out=270,in=0,looseness=5] node[below right] {$\pi$} ($(Box.south east)+(0,0.5)$);

    \draw[-stealth] ($(Box.south west)+(0.5,0)$) arc (360:90:0.5);
\end{tikzpicture}

\end{document}

Output

enter image description here

[xshift=] and friends makes it easier to arrange shifts etc. without the calc dependence — percusse, Nov 07 '13 at 12:51
Thank you very much! The left one is exactly what I wanted. I now tried to switch it to the south east side playing around with the parameters such as \draw[-stealth] ($(Box.south east)+(-0.5,0)$) arc (360:90:0.5); However, it does not bend in the right dirextion. I hope you can help again. Thanks in advance! — Lisa, Nov 07 '13 at 11:13

How to create a bent arrow at a rectangle corner?

1 Answers1

Code

Output