How to re-use a tikzpicture with coordinates

Question

I have a basic tikzpicture I want to re-use in other tikzpictures and be able to use the coordinates and paths defined within it.

For instance, I have a geometric figure used in a problem and the same geometric figure with labels used in a solution. If I put a tikzpicture inside a \newcommand, I can insert it in another tikzpicture, but the coordinates are messed up. In simple cases I can redefine them, but with complex figures I would like to be able to refer to the coordinates already defined from another tikzpicture.

In the template below the red node A in the second picture was created from the coordinates defined in the first picture: I would like it to be exactly on top of the lower-left, blue node A.

\documentclass[border=3mm]{standalone}
\usepackage{tikz}
\usetikzlibrary{calc}

\begin{document}

% basic figure to be reused
\newcommand{\basic}{%
  \begin{tikzpicture}[remember picture]% doesn't help

  \coordinate (A) at (0,0);
  \coordinate (B) at (1,1);
  \node [blue,below] at (A) {A};
  \draw [blue] (A) -- (B);

  \end{tikzpicture}
}%


\begin{tabular}{@{}c@{}}

\begin{tikzpicture}

  \node at (0,0) (pic1) {\basic};

\end{tikzpicture}

\vspace{1cm} \\

\begin{tikzpicture}

  \node at (0,0) (pic2) {\basic};

  \node [red,below] at (A) {A};

\end{tikzpicture}

\end{tabular}

\end{document}

Perhaps I can automate a coordinate adjustment in the second picture? Or maybe there is a better approach altogether. I tried to use the remember picture option, but didn't quite know how to.

I saw this question but Peter Grill, in his answer, writes "I am not recommending nesting tikzpicture environments." So I wonder what a better solution would be. There is also that question, but in my attempts to use a scope with a yshift, the coordinates were also shifted. Or did I miss something?

Answer 1

Instead of a \newcommand you can use a pic. This is what pic are for, reuse part of tikzpictures.

If the pic has a name, all inner nodes can be referenced combining pic's name and nodes' names. Here you have an example:

\documentclass[border=3mm]{standalone}
\usepackage{tikz}
\usetikzlibrary{calc}

\tikzset{
%basic figure to be reused
    myfig/.pic={
  \coordinate (A) at (0,0);
  \coordinate (B) at (1,1);
  \node [blue,below] at (A) {A};
  \draw [blue] (A) -- (B);
    }
}

\begin{document}

\begin{tabular}{@{}c@{}}

\begin{tikzpicture}

  \pic {myfig};

\end{tikzpicture}

\vspace{1cm} \\

\begin{tikzpicture}

  \pic (original) {myfig};

  \node [red,below] at (originalA) {A};

\end{tikzpicture}

\end{tabular}

\end{document}

Answer 2

The new scontents package does quite what you want, as it allows you to reuse content. IMO is quite slow, but so far it is the only caveat

%Standalone for illustrative purposes
\documentclass{standalone}
\usepackage[store-cmd=tikz]{scontents}
\usepackage{tikz}
\usetikzlibrary{positioning,calc}
%Called with \getstored[1]{tikz}
\Scontents*{\coordinate (A) at (0,0);
    \coordinate (B) at (1,1);
    \node [blue,below] at (A) {A};
    \draw [blue] (A) -- (B);}
%If you need more content, use
%\Scontents*{mycontent...}
\begin{document}
\begin{tabular}{c}
\begin{tikzpicture}
\getstored[1]{tikz}
\end{tikzpicture}
\\
\begin{tikzpicture}
\getstored[1]{tikz}
\node [red,below] at (A) {A};
\end{tikzpicture}
\end{tabular}
\end{document}