Is there a way to print two tikzpictures next to each other marked with a and b?

Question

I have the following code that should print the two figures next to each other with an a to the left of the first figure and a b to the left of the second one. The code below does this, but everything is aligned to the bottom line. Is there an option to force the pictures down? Or maybe a totally different way of avhiving my goal? Thanks!

\documentclass{scrbook}

\usepackage{tikz-qtree}

\begin{document}

\begin{figure}[htbp]
\centering
\begin{tabular}[t]{@{}ll@{\hspace{2cm}}ll@{}}
a. & \begin{tikzpicture}
\Tree[.N 
          [.PV pazirāi ]
          [.N 
            [.V kon- ] ande ] ]
\end{tikzpicture} &
b. &
\begin{tikzpicture}
\Tree[.N 
          [.V 
            [.PV pazirāi ]
            [.V kon- ] ] ande ] 
\end{tikzpicture}
\end{tabular}
\end{figure}


\end{document}

Answer 1

Here's an option using the floatrow and subfig packages; as an advantage of this approach, you don't have to manually label the figures and can easily control the vertical position of the labels; furthermore, you can cross-reference the subfigures:

\documentclass{scrbook}
\usepackage{tikz-qtree}
\usepackage{floatrow}
\usepackage{subfig}

\floatsetup[figure]{style=plain,subcapbesideposition=center}

\begin{document}

\begin{figure}
\sidesubfloat[]{%
\begin{tikzpicture}
\Tree[.N 
          [.PV pazirāi ]
          [.N 
            [.V kon- ] ande ] ]
\end{tikzpicture} 
}\qquad%
\sidesubfloat[]{%
\begin{tikzpicture}
\Tree[.N 
          [.V 
            [.PV pazirāi ]
            [.V kon- ] ] ande ] 
\end{tikzpicture}
}
\end{figure}

\end{document}

Simply loading the bidi package in the above solution (and processing with XeLaTeX), as in the following document:

\documentclass{scrbook}
\usepackage{tikz-qtree}
\usepackage{floatrow}
\usepackage{subfig}
\usepackage{bidi}

\floatsetup[figure]{style=plain,subcapbesideposition=center}

\begin{document}

\begin{figure}
\sidesubfloat[]{%
\begin{tikzpicture}
\Tree[.N 
          [.PV pazirāi ]
          [.N 
            [.V kon- ] ande ] ]
\end{tikzpicture} 
}\qquad%
\sidesubfloat[]{%
\begin{tikzpicture}
\Tree[.N 
          [.V 
            [.PV pazirāi ]
            [.V kon- ] ] ande ] 
\end{tikzpicture}
}
\end{figure}

\end{document}

produces the error

! LaTeX Error: \floatc@plain undefined.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
 ...                                              

l.16 \renewcommand\floatc@plain
                               [2]{\setbox\@tempboxa\hbox{{\@fs@cfont #1:} #2}%

? 

A workaround then is to define \floatc@plain before loading the bidi package; the definition can be found in the float.sty file; the following code can be processed without errors and produces the desired result:

\documentclass{scrbook}
\usepackage{tikz-qtree}
\usepackage{floatrow}
\usepackage{subfig}
\makeatletter
\newcommand\floatc@plain[2]{\setbox\@tempboxa\hbox{{\@fs@cfont #1:} #2}%
  \ifdim\wd\@tempboxa>\hsize {\@fs@cfont #1:} #2\par
    \else\hbox to\hsize{\hfil\box\@tempboxa\hfil}\fi}
\makeatother
\usepackage{bidi}

\floatsetup[figure]{style=plain,subcapbesideposition=center}

\begin{document}

\begin{figure}
\sidesubfloat[]{%
\begin{tikzpicture}
\Tree[.N 
          [.PV pazirāi ]
          [.N 
            [.V kon- ] ande ] ]
\end{tikzpicture} 
}\qquad%
\sidesubfloat[]{%
\begin{tikzpicture}
\Tree[.N 
          [.V 
            [.PV pazirāi ]
            [.V kon- ] ] ande ] 
\end{tikzpicture}
}
\end{figure}

\end{document}

Answer 2

The following example shows two methods to shift the tikz pictures. The first is using \raisebox{-.5\height}{...} that would also work with images. Then second uses a option baseline:

\documentclass{scrbook}

\usepackage{tikz-qtree}

\begin{document}

\begin{figure}[htbp]
\centering
\begin{tabular}[t]{@{}ll@{\hspace{2cm}}ll@{}}
a. & \raisebox{-.5\height}{\begin{tikzpicture}
\Tree[.N
          [.PV pazirai ]
          [.N
            [.V kon- ] ande ] ]
\end{tikzpicture}} &
b. &
\begin{tikzpicture}[baseline=(current bounding box.center)]
\Tree[.N
          [.V
            [.PV pazirai ]
            [.V kon- ] ] ande ]
\end{tikzpicture}
\end{tabular}
\end{figure}

\end{document}

Answer 3

You can also use one TikZ picture and the local bounding box options but I would recommend using the subcaption package to handle your subfigures properly. Here is an example:

\documentclass{scrbook}

\usepackage{tikz-qtree}
\usetikzlibrary{positioning}

\begin{document}

\begin{figure}[htbp]
\centering
\begin{tikzpicture}

\begin{scope}[local bounding box=aa]
\Tree[.N 
          [.PV pazirāi ]
          [.N 
            [.V kon- ] ande ] ]

\end{scope}

\begin{scope}[shift={(6,0)},local bounding box=bb]
\Tree[.N 
          [.V 
            [.PV pazirāi ]
            [.V kon- ] ] ande ] 

\end{scope}

\node[right = -1cm of aa.west] {a.)};
\node[right = -1cm of bb.west] {b.)};

\end{tikzpicture}
\end{figure}


\end{document}

It might need additional shifts if the scope heights are different.

Answer 4

This solution doesn't give the format you requested, but it uses the subcaption to give (a) and (b) below each subfigure. Note that a lot of people reading your document will expect to see the captions below the figures, and won't necessarily be looking for them to the side.

Using this approach is somewhat advantageous because you can reference them easily using the standard label and ref techniques.

\documentclass{article}

\usepackage{tikz-qtree}
\usepackage{subcaption}

\begin{document}

\begin{figure}[htbp]
    \begin{subfigure}{.5\textwidth}
        \centering
        \begin{tikzpicture}
            \Tree[.N 
            [.PV pazirāi ]
            [.N 
            [.V kon- ] ande ] ]
        \end{tikzpicture} 
        \caption{First subpicture}
        \label{fig:myfirstsubfig}
    \end{subfigure}%
    \begin{subfigure}{.5\textwidth}
        \centering
        \begin{tikzpicture}
            \Tree[.N 
            [.V 
            [.PV pazirāi ]
            [.V kon- ] ] ande ] 
        \end{tikzpicture}
        \caption{Second subpicture}
        \label{fig:mysecondsubfig}
    \end{subfigure}
\end{figure}

\end{document}

Answer 5

Another option for manual labeling is too put the figures into minipages. I use this technique to align all kind of figures, especially when the baseline of the figure can not be controlled (which is possible for TikZ figures though).

\documentclass{article}
\usepackage{tikz-qtree}
\makeatletter
\newsavebox{\my@figbox}
\newcommand{\myfigbox}[2][\empty]{
  \if#1\empty\else\textbf{#1}\fi%
  \savebox{\my@figbox}{#2}%
  \begin{minipage}[c]{\wd\my@figbox}
    \centering\vspace{0pt}
    \usebox{\my@figbox}%
  \end{minipage}%
}
\makeatother
\begin{document}

\myfigbox[a.]{%
\begin{tikzpicture}
  \Tree[.N 
          [.PV pazirai ]
          [.N 
            [.V kon- ] ande ] ]
\end{tikzpicture}
}%
\myfigbox[b.]{%
\begin{tikzpicture}
\Tree[.N 
          [.V 
            [.PV pazirai ]
            [.V kon- ] ] ande ] 
\end{tikzpicture}
}

\end{document}

Often space can be saved by laying the labels over the figure. For this one can modify the \myfigbox macro as follows:

\newcommand{\myfigbox}[2][\empty]{
  \if#1\empty\else\makebox[0pt][l]{\textbf{#1}}\fi%
  \savebox{\my@figbox}{#2}%
  \begin{minipage}[t]{\wd\my@figbox}
    \centering\vspace{0pt}
    \usebox{\my@figbox}%
  \end{minipage}%
}

which yields