tikz arrow outside tikzpicture environment

Question

Is it possible draw an arrow in a tikzpicture environment so that the arrows goes outside the environment? Here's my specific scenario ...

I have a verbatim environment (basically for program code) and I want to draw a boxed text in a margin/sidebar and attach an arrow from this point to a line in the verbatim environment.

Answer 1

This is easily doable using, what else, but \tikzmark. You need to have a way within the verbatim environment to escape back to LaTeX temporarily in order to place the \tikzmark within the verbatim environment. Below I used the verbatim environment provided by the listings package, and escapeinside to provide a way to execute LaTeX macros.

Arrow:

Box and Arrow:

You can extend this to draw the box as well. I have extended \DrawArrow to \DrawBoxAndArrow in the same macro (but perhaps you want a separate macro for that):

Notes:

• This does require two runs. First one to determine the locations, and the second to do the drawing.

• The \tikzmark is from Adding a large brace next to a body of text.

• To ensure that the arrow does not cross over the text, you will need to choose the in=, and out= angles which are provided as the first optional parameter to the \DrawArrow macro. Using out=-60 was enough to get the arrow to curve around the verbatim text at the end of the line.

---

Code (arrow):

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{calc}
\usepackage{listings}

\newcommand{\tikzmark}[1]{\tikz[overlay,remember picture] \node (#1) {};}
\newcommand*{\DrawArrow}[3][]{%
    % #1 = draw options
    % #2 = left point
    % #3 = right point
    \begin{tikzpicture}[overlay,remember picture]
        \draw [-latex, #1] ($(#2)+(0.1em,0.5ex)$) to ($(#3)+(0,0.5ex)$);
    \end{tikzpicture}%
}%


\begin{document}
Here is some text from which I want to draw an arrow from here\tikzmark{start} into the verbatim environment below.

\begin{lstlisting}[escapeinside={(*}{*)}]
  verbatim line 1
  Here is a verbatim line and I want the arrow to 
      point here(*\tikzmark{end}*)
  verbatim line 3
\end{lstlisting}
\DrawArrow[red, thick, out=-60, in=0]{start}{end}
\end{document}

---

Code: (box and arrow):

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{calc}
\usepackage{listings}

\newcommand{\tikzmark}[1]{\tikz[overlay,remember picture] \node (#1) {};}

\newcommand*{\DrawBoxAndArrow}[4][]{%
    % #1 = draw options
    % #2 = left point, start of box
    % #3 = right point, end of box
    % #4 = point where arrow ends
    \begin{tikzpicture}[overlay,remember picture]
        \draw [#1] ($(#2)-(0.1em,0.25ex)$) rectangle ($(#3)+(0.1em,1.5ex)$);
        \draw [-latex, #1] ($(#3)+(0.1em,0.5ex)$) to ($(#4)+(0,0.5ex)$);
    \end{tikzpicture}%
}%

\begin{document}
Here is some text from which I want to draw an arrow from \tikzmark{startBox}here\tikzmark{endBox} into the verbatim environment below.

\begin{lstlisting}[escapeinside={(*}{*)}]
  verbatim line 1
  Here is a verbatim line and I want the arrow to 
      point here(*\tikzmark{endArrow}*)
  verbatim line 3
\end{lstlisting}
\DrawBoxAndArrow[red, thick, out=-60, in=0]{startBox}{endBox}{endArrow}
\end{document}