Table of 2x2 tikzpictures

Question

I'm attempting to condense 4 tikzpictures into a smaller space in my document. The solution I have is as follows:

\documentclass{article}
\usepackage[paperwidth=6in, paperheight=4in]{geometry}
\usepackage[english]{babel}
\usepackage[utf8x]{inputenc}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{tikz}
\usepackage{multicol}

\begin{document}

Examples

\begin{multicols}{2}

\begin{tikzpicture}[xscale=.5, yscale=.5]
\draw [<->,thick] (0,5) |- (5,0);
\draw [thick] (4,1) --(4,4) node [right] {$A$ is not open in $\mathbb{R}^{2}$.};
\draw [thick, dashed] (4,1) -- (1,1) -- (1,4) -- (4,4);
\draw [fill] (4,1) circle [radius=0.1];
\draw [fill] (4,4) circle [radius=0.1];
\node at (2.5,2.5) {$A$};
\end{tikzpicture}

\begin{tikzpicture}[xscale=.5, yscale=.5]
\draw [<->,thick] (0,5) |- (5,0);
\draw [thick, dashed] (1,1) to [out=90, in=280] (1,4) to [out=30, in=150] (2,3.5) to [out=30, in=200] (4,4) to [out=40, in=90] (5,3) to [out=270, in=90] node [right] {$A$ is open.} (4,1) to [out=180, in=30] (1,1);
\node at (2.5,2.5) {$A$};
\end{tikzpicture}

\begin{tikzpicture}[xscale=.5, yscale=.5]
\draw [<->,thick] (0,5) |- (5,0);
\draw [fill] (4,1) circle [radius=0.1];
\draw [fill] (2,1) circle [radius=0.1];
\draw [fill] (3,5) circle [radius=0.1];
\draw [fill] (1,3) circle [radius=0.1];
\node at (5,3) {$A$ is not open.};
\end{tikzpicture}

$\newline$

\begin{tikzpicture}[xscale=.5, yscale=.5]
\draw [<->,thick] (0,2) |- (5,0);
\draw [ultra thick] (1,0) --(3,0) node [above] {$A$};
\node at (7,-1) {$A$ is not open in $\mathbb{R}^{2}$ but open in $\mathbb{R}$.};
\draw [fill=white] (1,0) circle [radius=0.1];
\draw [fill=white] (3,0) circle [radius=0.1];
\end{tikzpicture}

\end{multicols}

\end{document}

This produces:

The solution involves creating columns and placing the tikzpictures within the columns and forcing them to separate with a \newline.

But this is, in my opinion, an ugly solution. I'd like to be able to place the 4 tikzpictures in a 2x2 grid, each tikzpicture horizontally and vertically centered within it's cell plus turning each node that currently acts as a label (e.g. "A is open.") into a caption for that tikzpicture.

I tried to do this before by placing each tikzpicture within a minipage, but then this can't be captioned (something about float and absolute figures?), also I tried putting \figures of minipages of tikzpictures which, obviously, didn't work and became messy quickly.

Is there a simple solution to this?

Answer 1

While tabularx works, it's a bit overkill in this case.

\documentclass{article}
\usepackage[paperwidth=7in, paperheight=5in]{geometry}
\usepackage[english]{babel}
\usepackage[utf8x]{inputenc}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{tikz}
\usepackage[labelformat=empty]{caption}
\usepackage{tabularx}

\begin{document}

Examples
\begin{center}
\begin{minipage}[b]{.5\textwidth}
\centering
\begin{tikzpicture}[xscale=.5, yscale=.5]
\draw [<->,thick] (0,5) |- (5,0);
\draw [thick] (4,1) --(4,4);
\draw [thick, dashed] (4,1) -- (1,1) -- (1,4) -- (4,4);
\draw [fill] (4,1) circle [radius=0.1];
\draw [fill] (4,4) circle [radius=0.1];
\node at (2.5,2.5) {$A$};
\end{tikzpicture}
\captionof{figure}{$A$ is not open in $\mathbb{R}^{2}$.}
\end{minipage}%
\begin{minipage}[b]{.5\textwidth}
\centering
\begin{tikzpicture}[xscale=.5, yscale=.5]
\draw [<->,thick] (0,5) |- (5,0);
\draw [thick, dashed] (1,1) to [out=90, in=280] (1,4) to [out=30, in=150] (2,3.5) to [out=30, in=200] (4,4) to [out=40, in=90] (5,3) to [out=270, in=90] (4,1) to [out=180, in=30] (1,1);
\node at (2.5,2.5) {$A$};
\end{tikzpicture}
\captionof{figure}{$A$ is open.}
\end{minipage}

\medskip

\begin{minipage}[b]{.5\textwidth}
\centering
\begin{tikzpicture}[xscale=.5, yscale=.5]
\draw [<->,thick] (0,5) |- (5,0);
\draw [fill] (4,1) circle [radius=0.1];
\draw [fill] (2,1) circle [radius=0.1];
\draw [fill] (3,5) circle [radius=0.1];
\draw [fill] (1,3) circle [radius=0.1];
\end{tikzpicture}
\captionof{figure}{$A$ is not open.}
\end{minipage}%
\begin{minipage}[b]{.5\textwidth}
\centering
\begin{tikzpicture}[xscale=.5, yscale=.5]
\draw [<->,thick] (0,2) |- (5,0);
\draw [ultra thick] (1,0) --(3,0) node [above] {$A$};
\draw [fill=white] (1,0) circle [radius=0.1];
\draw [fill=white] (3,0) circle [radius=0.1];
\end{tikzpicture}
\captionof{figure}{$A$ is not open in $\mathbb{R}^{2}$ but open in $\mathbb{R}$.}
\end{minipage}
\end{center}

\end{document}

Note the % after the first \end{minipage} in each row, to avoid a spurious space. The center environment is just to remove indentations and to give some room after "Examples".

Use a different vertical space command instead of \medskip, if you prefer.

The \label commands are useless, as you don't number the captions. In any case, the strings should be different from each other.

Answer 2

The solution I've settled on uses the tabularx package. I'm not sure why this allows captions when the tabular package gave me errors, but it does.

Here's the code:

\documentclass{article}
\usepackage[paperwidth=7in, paperheight=5in]{geometry}
\usepackage[english]{babel}
\usepackage[utf8x]{inputenc}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{tikz}
\usepackage[labelformat=empty]{caption}
\usepackage{tabularx}

\begin{document}

Examples

\begin{tabularx}{\textwidth}{ X X }
\begin{tikzpicture}[xscale=.5, yscale=.5]
\draw [<->,thick] (0,5) |- (5,0);
\draw [thick] (4,1) --(4,4);
\draw [thick, dashed] (4,1) -- (1,1) -- (1,4) -- (4,4);
\draw [fill] (4,1) circle [radius=0.1];
\draw [fill] (4,4) circle [radius=0.1];
\node at (2.5,2.5) {$A$};
\end{tikzpicture}
\captionof{figure}{$A$ is not open in $\mathbb{R}^{2}$.}
\label{tikz}

&

\begin{tikzpicture}[xscale=.5, yscale=.5]
\draw [<->,thick] (0,5) |- (5,0);
\draw [thick, dashed] (1,1) to [out=90, in=280] (1,4) to [out=30, in=150] (2,3.5) to [out=30, in=200] (4,4) to [out=40, in=90] (5,3) to [out=270, in=90] (4,1) to [out=180, in=30] (1,1);
\node at (2.5,2.5) {$A$};
\end{tikzpicture}
\captionof{figure}{$A$ is open.}
\label{tikz}

\\

\begin{tikzpicture}[xscale=.5, yscale=.5]
\draw [<->,thick] (0,5) |- (5,0);
\draw [fill] (4,1) circle [radius=0.1];
\draw [fill] (2,1) circle [radius=0.1];
\draw [fill] (3,5) circle [radius=0.1];
\draw [fill] (1,3) circle [radius=0.1];
\end{tikzpicture}
\captionof{figure}{$A$ is not open.}
\label{tikz}

&

\begin{tikzpicture}[xscale=.5, yscale=.5]
\draw [<->,thick] (0,2) |- (5,0);
\draw [ultra thick] (1,0) --(3,0) node [above] {$A$};
\draw [fill=white] (1,0) circle [radius=0.1];
\draw [fill=white] (3,0) circle [radius=0.1];
\end{tikzpicture}
\captionof{figure}{$A$ is not open in $\mathbb{R}^{2}$ but open in $\mathbb{R}$.}
\label{tikz}

\end{tabularx}

\end{document}

And what it produces:

Although the captions don't seem "centered" below each tikzpicture, I'm satisfied.