Align independent tikzpictures

Question

I have two tikzpictures:

\documentclass{article}
\usepackage{tikz}
\usepackage{subcaption}
\usetikzlibrary{shapes,arrows}
\begin{document}
\pagestyle{empty}

\tikzstyle{notarget} = [rectangle, rounded corners, minimum
  width=1cm, minimum height=1cm,text centered, draw=none,
  opacity=0,text opacity=1,align=center]
\tikzstyle{target} = [rectangle, rounded corners, minimum width=1cm, minimum
  height=1cm,text centered, draw=black, very thick,text
  opacity=1,align=center]

\begin{figure}[ht]
  \centering
  \begin{subfigure}[b]{0.3\textwidth}
    \begin{tikzpicture}[node distance=1.2cm]
      \node (n1) [notarget] {I\\PRP};
      \node (n2) [notarget, right of=n1] {saw\\VBD};
      \node (n3) [target, right of=n2] {a\\DT};
      \node (n4) [target, right of=n3] {girl\\NN};
%      \draw [thick,->] (n4) -- ++(1cm,0);
    \end{tikzpicture}
    \caption{}
  \end{subfigure}
  \qquad\qquad
  \centering
  \begin{subfigure}[b]{0.3\textwidth}
    \begin{tikzpicture}[node distance=1.2cm]
      \node (n1) [notarget] {I\\PRP};
      \node (n2) [notarget, right of=n1] {saw\\VBD};
      \node (n3) [target, right of=n2] {a\\DT};
      \node (n4) [target, below of=n3,anchor=north] {girl\\NN};
      \draw [thick,->] (n4) -- (n3);
    \end{tikzpicture}
    \caption{}
  \end{subfigure}
  \label{fig:rightaction}
\end{figure}
\end{document}

But I do not know how to align the to figures vertically, currently it shows like this:

I would like to align it like this:

I have tried the following answers, without success:

UPDATE

I get it working with the help of Guilherme, here is:

\begin{figure}[ht]
  \centering
  \begin{subfigure}[b]{0.4\textwidth}
    \begin{tikzpicture}[node distance=2mm]
      \node (n1) [notarget] {I\\PRP};
      \node (n2) [notarget, right=of n1] {saw\\VBD};
      \node (n3) [target, right=of n2] {a\\DT};
      \node (n4) [target, right=of n3] {girl\\NN};
      \node (n4') [target, right=of n4,draw=none,anchor=west] {};
      \node (n5') [target, below=5mm of n4',anchor=north,draw=none] {};
      \draw [thick,->] (n5'.center) -- ++(5mm,0);
    \end{tikzpicture}
    \caption{}
  \end{subfigure}
  \qquad\qquad
  \centering
  \begin{subfigure}[b]{0.4\textwidth}
    \begin{tikzpicture}[node distance=2mm]
      \node (n1) [notarget] {I\\PRP};
      \node (n2) [notarget, right=of n1] {saw\\VBD};
      \node (nn) [notarget,draw=none,right=of n2] {};
      \node (n3) [target, right=of nn] {girl\\NN};
      \node (n4) [target, below=5mm of n3] {a\\DT};
      \draw [thick,->] (n4) -- (n3);
    \end{tikzpicture}
    \caption{}
  \end{subfigure}
\end{figure}

And the result:

UPDATE 2

Finally I've used gemot's solution:

\begin{figure}[ht]
  \centering
  \begin{tabular}{p{0.4\textwidth}cp{0.4\textwidth}}
    \begin{tikzpicture}[node distance=2mm,baseline=(n3)]
      \node (n1) [notarget] {I\\PRP};
      \node (n2) [notarget, right=of n1] {saw\\VBD};
      \node (n3) [target, right=of n2] {a\\DT};
      \node (n4) [target, right=of n3] {girl\\NN};
    \end{tikzpicture}
  &
    \tikz\draw [thick,->] (0,0) -- ++(.5cm,0);
  &
    \begin{tikzpicture}[node distance=2mm,baseline=(n3)]
      \node (n1) [notarget] {I\\PRP};
      \node (n2) [notarget, right=of n1] {saw\\VBD};
      \node (n3) [target, right=of n2] {a\\DT};
      \node (n4) [target, below=5mm of n3,anchor=north] {girl\\NN};
      \draw [thick,->] (n4) -- (n3);
    \end{tikzpicture}
  \\
    \subcaption{}
  &&
    \subcaption{}
  \end{tabular}
  \label{fig:rightaction}
\end{figure}

One way would be to use \tikzmark(many examples on this site) to mark an alignment point in the first picture and use that in the second picture to do the alignment. This will require two consiecutive runs of pdflatex. — Peter Grill, Dec 08 '16 at 06:24
If you can't get it to work fully post how far you got and am sure someone here will help out. — Peter Grill, Dec 08 '16 at 06:46

score 4 · Answer 1 · answered Dec 08 '16 at 07:26

There are probably lots of ways to do this. Two I can see easily implemented: (i) use a \savebox and \raisebox or (ii) do the same drawing, but invisible (with \path). I'll show only the second because I think it's considerably less complicated and, as far as I know, the \savebox/\raisebox solution is already in the site.

\documentclass{article}
\usepackage{tikz,calc}
\usepackage{subcaption}
\usetikzlibrary{shapes,arrows}
\begin{document}
\pagestyle{empty}

\tikzset{notarget/.style={rectangle, rounded corners, minimum
  width=1cm, minimum height=1cm,text centered, draw=none,
  opacity=0,text opacity=1,align=center},
    target/.style={rectangle, rounded corners, minimum width=1cm, minimum
  height=1cm,text centered, draw=black, very thick,text
  opacity=1,align=center}}

\begin{figure}[ht]
  \centering
  \begin{subfigure}[b]{0.3\textwidth}
    \begin{tikzpicture}[node distance=1.2cm]
      \node (n1) [notarget] {I\\PRP};
      \node (n2) [notarget, right of=n1] {saw\\VBD};
      \node (n3) [target, right of=n2] {a\\DT};
      \node (n4) [target, right of=n3] {girl\\NN};
      \node (n4') [target, below of=n3,anchor=north,draw=none] {};% <<<<<<< INVISIBLE
      \path [thick,->] (n4) -- (n3);% <<<<<<<<<<< INVISIBLE
%      \draw [thick,->] (n4) -- ++(1cm,0);
    \end{tikzpicture}
    \caption{}
  \end{subfigure}
  \qquad\qquad
  \centering
  \begin{subfigure}[b]{0.3\textwidth}
    \begin{tikzpicture}[node distance=1.2cm]
      \node (n1) [notarget] {I\\PRP};
      \node (n2) [notarget, right of=n1] {saw\\VBD};
      \node (n3) [target, right of=n2] {a\\DT};
      \node (n4) [target, below of=n3,anchor=north] {girl\\NN};
      \draw [thick,->] (n4) -- (n3);
    \end{tikzpicture}
    \caption{}
  \end{subfigure}
  \label{fig:rightaction}
\end{figure}
\end{document}

score 4 · Accepted Answer · answered Dec 08 '16 at 11:30

Here is a solution that does not require phantom drawings.

Use the baseline option of tikzpicture to specify the horizonal alignment.
Use some tabular environment for the overall arrangement. Because of the captions, you have to use p columns or some other type creating a box.

\documentclass{article}
\usepackage{tikz}
\usepackage{subcaption}
\usetikzlibrary{shapes,arrows}
\begin{document}
\pagestyle{empty}
\tikzset
  {common/.style =
    {rectangle, rounded corners, minimum width=1cm, minimum height=1cm,
     text centered, text opacity=1, align=center
    }
  ,notarget/.style = {common, draw=none, opacity=0}
  ,target/.style   = {common, draw=black, very thick}
  }

\begin{figure}[ht]
  \centering
  \begin{tabular}{p{0.4\textwidth}cp{0.4\textwidth}}
    \begin{tikzpicture}[node distance=1.2cm,baseline=(n3)]
      \node (n1) [notarget] {I\\PRP};
      \node (n2) [notarget, right of=n1] {saw\\VBD};
      \node (n3) [target, right of=n2] {a\\DT};
      \node (n4) [target, right of=n3] {girl\\NN};
    \end{tikzpicture}
  &
    \tikz\draw [thick,->] (0,0) -- ++(1cm,0);
  &
    \begin{tikzpicture}[node distance=1.2cm,baseline=(n3)]
      \node (n1) [notarget] {I\\PRP};
      \node (n2) [notarget, right of=n1] {saw\\VBD};
      \node (n3) [target, right of=n2] {a\\DT};
      \node (n4) [target, below of=n3,anchor=north] {girl\\NN};
      \draw [thick,->] (n4) -- (n3);
    \end{tikzpicture}
  \\
    \subcaption{before}
  &&
    \subcaption{after}
  \end{tabular}
  \caption{A transformation}\label{fig:rightaction}
\end{figure}
\end{document}

I am going to keep with this solution, thanks! – Alejandro Alcalde Dec 08 '16 at 11:40 — Alejandro Alcalde, Dec 08 '16 at 11:40

Align independent tikzpictures

2 Answers2