It is possible to reuse TikZ code?

Question

Let say one create the following figure and save it in a file figure.tex:

\documentclass{scrartcl}
\usepackage{tikz}
\usetikzlibrary{
                arrows.meta,
                bending,
                positioning
               }
\tikzset{
         > = Latex,
         arrows = {[bend]},
         signal/.style = coordinate,
         sum/.style = {
                       draw,
                       circle,
                       minimum size = 2mm
                      },
         block/.style = {
                         draw,
                         rectangle,
                         minimum height = 2em,
                         minimum width = 4em
                        },
         branch/.style = {
                          sum,
                          minimum size = 1mm,
                          fill = black
                         }
        }

\begin{document}

  \begin{tikzpicture}[auto]

    %placing the nodes
    \node[signal] (input) {};
    \node[sum, right = of input] (left sum) {};
    \node[block, right = of left sum] (controller) {$G_R$};
    \node[block, right = of controller] (system) {$G_S$};
    %connecting the controller and system to get the coordinates of u, its needed for the placement of the measurement block
    \draw
      [->] (controller) -- node[name = u] {$U$} (system);
    \node[block, above = of system] (dynamic of disturbances) {$G_D$};
    \node[signal, left = of dynamic of disturbances] (disturbances) {};
    \node[sum, right = of system] (right sum) {};
    \node[branch, right = of right sum] (branch) {};
    \node[signal, right = of branch] (output) {};
    \node[sum, below = of branch] (lower sum) {};
    \node[signal, right = of lower sum] (measurement noise) {};
    \node[block] (measurement) at (u |- lower sum) {$G_M$};
    %connecting the nodes
    \draw
      [->] (input) -- node {$W$} (left sum);
    \draw
      [->] (left sum) -- node {$E$} (controller);
    \draw
      [->] (system) -- (right sum);
    \draw
      [->] (disturbances) -- node {$Z$} (dynamic of disturbances);
    \draw
      [->] (dynamic of disturbances) -| (right sum);
    \draw
      (right sum) -- (branch);
    \draw
      [->] (branch) -- node {$Y$} (output);
    \draw
      [->] (branch) -- (lower sum);
    \draw
      [->] (measurement noise) -- node[above] {$M$} (lower sum);
    \draw
      [->] (lower sum) -- (measurement);
    \draw
      [->] (measurement) -| node[pos = .95] {$-$} (left sum);

  \end{tikzpicture}

\end{document}

Result:

Than one wish to load the file with \input{figure} and adding some code to it (without changing the file figure.tex), for example arrows, see my releated question. Is it possible?

do you know the chains library? It is quite useful to draw control circuits. — Robert Seifert, Nov 29 '19 at 15:31

score 14 · Accepted Answer · answered Nov 22 '19 at 11:31

Why don't you put everything in a macro? In that example I am using a scope to be able to use auto in your graph and not outside, but this is not needed if you use auto everywhere...

In iii.tex:

%%% probably is better left in your main file, but nothing happens if you have this 
%%% multiple times
%%%
\usepackage{tikz}
%%%
%%% ditto
%%%
\usetikzlibrary{
                arrows.meta,
                bending,
                positioning
               }
\tikzset{
         > = Latex,
         arrows = {[bend]},
         signal/.style = coordinate,
         sum/.style = {
                       draw,
                       circle,
                       minimum size = 2mm
                      },
         block/.style = {
                         draw,
                         rectangle,
                         minimum height = 2em,
                         minimum width = 4em
                        },
         branch/.style = {
                          sum,
                          minimum size = 1mm,
                          fill = black
                         }
        }

\newcommand{\mygraph}{%
    \begin{scope}[auto]
    %placing the nodes
    \node[signal] (input) {};
    \node[sum, right = of input] (left sum) {};
    \node[block, right = of left sum] (controller) {$G_R$};
    \node[block, right = of controller] (system) {$G_S$};
    %connecting the controller and system to get the coordinates of u, its needed for the placement of the measurement block
    \draw
      [->] (controller) -- node[name = u] {$U$} (system);
    \node[block, above = of system] (dynamic of disturbances) {$G_D$};
    \node[signal, left = of dynamic of disturbances] (disturbances) {};
    \node[sum, right = of system] (right sum) {};
    \node[branch, right = of right sum] (branch) {};
    \node[signal, right = of branch] (output) {};
    \node[sum, below = of branch] (lower sum) {};
    \node[signal, right = of lower sum] (measurement noise) {};
    \node[block] (measurement) at (u |- lower sum) {$G_M$};
    %connecting the nodes
    \draw
      [->] (input) -- node {$W$} (left sum);
    \draw
      [->] (left sum) -- node {$E$} (controller);
    \draw
      [->] (system) -- (right sum);
    \draw
      [->] (disturbances) -- node {$Z$} (dynamic of disturbances);
    \draw
      [->] (dynamic of disturbances) -| (right sum);
    \draw
      (right sum) -- (branch);
    \draw
      [->] (branch) -- node {$Y$} (output);
    \draw
      [->] (branch) -- (lower sum);
    \draw
      [->] (measurement noise) -- node[above] {$M$} (lower sum);
    \draw
      [->] (lower sum) -- (measurement);
    \draw
      [->] (measurement) -| node[pos = .95] {$-$} (left sum);
\end{scope}}

and in your main file:

\documentclass{scrartcl}
\input{iii}

\begin{document}

\begin{tikzpicture}[auto]
    \mygraph
    %% add things
    \draw[red] (measurement) circle[radius=2cm];
\end{tikzpicture}

\end{document}

which gives the expected:

@gr4nt3d Yes, you can write it as a .sty file --- and the use \usepackage{} to call it. Depending on how much you share the specific code among prjects, can be worth the effort or not... — Rmano, Nov 23 '19 at 17:51

It is possible to reuse TikZ code?

1 Answers1

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