Orthogonal path routing

Question

TLDR; Is there a way I can specify a start and end point it it would route (hopefully orthogonally) around all nodes and other paths.

I'm converting a large number of visio flow charts to TikZ and keep running into one issue. Orthogonal* paths with more than one bend are hard to do. I'm also trying to keep the diagrams dynamic so any future changes can be made without tweaking the chart a bunch.

Now, I'm able to make these and keep them dynamic, but it seems much harder than it should be. Take the red line: that line required a minimum of 3 distinct points and to keep it dynamic, I ended up using 5! It would be nice if I could just specify a start and end point it it would route around all nodes and other paths.

*I'm using terminology from Omnigraffle, so what I mean is that any change in direction for the path is multiple of 90 degrees.

\documentclass{article}

\usepackage{tikz}
\usepackage[margin=0.5in]{geometry}
\pagestyle{empty}

\begin{document}

%\input{../tikz-setup.tex}
\usetikzlibrary{shapes, arrows, calc, positioning}

% Define block styles
\tikzstyle{state}   = [ rounded rectangle, 
                        draw, 
                        text centered, 
                        minimum height=3em ,
                        minimum width = 6em,
                        inner sep = 5pt
                      ]
\tikzstyle{test}    = [ diamond, 
                        draw, 
                        shape aspect=2, 
                        inner sep = 0pt,
                        text width = 7em,
                        text centered
                      ]
\tikzstyle{action}  = [ rectangle, draw,
                        text width=8em,
                        inner sep = 5pt, 
                        minimum height=5em
                      ]
\tikzstyle{data}    = [ trapezium, 
                        draw, 
                        trapezium left angle=60, 
                        trapezium right angle=120pt,
                        minimum height = 6em, 
                        text width = 5em
                       ]
\tikzstyle{line}    = [ draw, -triangle 45 ]

\begin{center}
\begin{tikzpicture}[align = flush center, font = \small]
    % Place nodes
    \matrix [column sep = 2.5em, row sep = 2em] (mtrx)
    {

    \node [state] (a) {a}; &[1em]
    \node (b) {}; \\

    \node [action] (c) {c}; &
    \node [action] (d) {d}; \\

    \node [test] (e) {e}; &
    \node [test] (f) {f}; \\

   \node [action] (g) {g}; &
    \node [action] (h) {h}; \\

    \node [action] (i) {i};&
    \node [action] (j) {j}; \\

    &
    \node [state] (k) {k}; \\
    };

    % Draw edges
    \path [line] (a) -- (c);
    \path [line] (c) -- (e);

    \path [line] (e) -- node [right, near start] {Yes} (g);
    \path [line] (e.east) -- node [above] {No} ( $(e.east)!0.3!(f.west)$ ) |- ( $(g)!0.45!(i)$ );

    \path [line] (g) -- (i);

    \path [line,red] let \p1=( $(a.south)!0.6!(b.south)$ ) in (i.south) -- +(0, -0.5) -| (\p1) -| (d.north);


\end{tikzpicture}
\end{center}
\end{document}

original image

Answer 1

if you often need this functionality, I recommend this to create a specific command, eg

\newcommand{\renvoi}[3][pos=0.5]{
\path (#2) -- (#3)coordinate[#1](mm);
\draw[-latex,green] (#2) --($(#2.south)+(0,-0.5)$)-| (mm) |- ($(#3.north)+(0,0.5)$)--(#3);
}

You'll be able to use almost all returns as in the example below

\documentclass{article}

\usepackage{tikz}
\usetikzlibrary{positioning}
\usepackage[margin=0.5in]{geometry}
\pagestyle{empty}


\newcommand{\renvoi}[3][pos=0.5]{
\path (#2) -- (#3)coordinate[#1](mm);
\draw[-latex,red] (#2) --($(#2.south)+(0,-0.5)$)-| (mm) |- ($(#3.north)+(0,0.5)$)--(#3);
}

\begin{document}

%\input{../tikz-setup.tex}
\usetikzlibrary{shapes, arrows, calc, positioning}

% Define block styles
\tikzstyle{state}   = [ rounded rectangle, 
                        draw, 
                        text centered, 
                        minimum height=3em ,
                        minimum width = 6em,
                        inner sep = 5pt
                      ]
\tikzstyle{test}    = [ diamond, 
                        draw, 
                        shape aspect=2, 
                        inner sep = 0pt,
                        text width = 7em,
                        text centered
                      ]
\tikzstyle{action}  = [ rectangle, draw,
                        text width=8em,
                        inner sep = 5pt, 
                        minimum height=5em
                      ]
\tikzstyle{data}    = [ trapezium, 
                        draw, 
                        trapezium left angle=60, 
                        trapezium right angle=120pt,
                        minimum height = 6em, 
                        text width = 5em
                       ]
\tikzstyle{line}    = [ draw, -triangle 45 ]

\begin{center}
\begin{tikzpicture}[align = flush center, font = \small]
    % Place nodes
    \matrix [column sep = 2.5em, row sep = 2em] (mtrx)
    {

    \node [state] (a) {a}; &[1em]
    \node (b) {}; \\

    \node [action] (c) {c}; &
    \node [action] (d) {d}; \\

    \node [test] (e) {e}; &
    \node [test] (f) {f}; \\

   \node [action] (g) {g}; &
    \node [action] (h) {h}; \\

    \node [action] (i) {i};&
    \node [action] (j) {j}; \\

    &
    \node [state] (k) {k}; \\
    };

    % Draw edges


\renvoi{i}{j}
\renvoi{e}{g}
\renvoi[left=3em of g]{e}{i}
\renvoi[pos=0.7]{f}{c}
\renvoi[right=3em of f]{f}{d}

\end{tikzpicture}
\end{center}
\end{document}

indicating the option selected by you or pass your link

• in the middle of the two nodes \renvoi{i}{j} default
• \renvoi\[pos=0.7\]{f}{c} the crossing point is 0.7 on the segment (f) (c)
• \renvoi[right=3em of f]{f}{d} the crossing point is to the right of 3em (positioning the library is required to use this option)

it has yet to improve this command to draw the link in all cases even add text or change the style of the link.