Something's wrong--perhaps a missing \item. \end{frame}: tikzpicture

Question

I have following tikzpicture in my presentation:

\begin{frame}{Unitary bounds}
\begin{figure}
    \scalebox{.7}{
\begin{center}
\begin{tikzpicture}
\fill[red,opacity=.2] (-.5,-1) rectangle (4,3);
\fill[green!80!black,opacity=.2] (-.5,3) rectangle (4,5);
\draw[very thick,green!80!black] (-1,3) -- (5,3) node[right, black] {$\Delta=\Delta_A$};
\draw[very thick, green!80!black] (-1,1) -- (5,1) node[right,black] {$\Delta=\Delta_B$};
\draw[thick,->] (0,-1) -- (0,5.5) node[right] {$\Delta$};
\node at (2,2) {non-unitary};
\node at (2,0) {non-unitary};
\node at (2,4) {unitary};
\end{tikzpicture}
\end{center}}
\caption{Unitarity structure of superconformal multiplets.}\label{fig:unitarity}
\end{figure}
\end{frame}

But unfortunately this lead to

Something's wrong--perhaps a missing \item. \end{frame}

don't put a center environment inside a scalebox. That makes no sense at all. — Ulrike Fischer, Jul 08 '20 at 16:32

muzimuzhi Z · Accepted Answer · 2020-07-08T17:10:11.077

After commenting out center environment and loading tikz package, your problem disappears.
Also, you can void \scalebox by using tikz option scale=0.7 instead. If you do want to scale the node text as well, use every node/.append style={scale=0.7} as suggested in How to scale a tikzpicture including texts?.
~~In the following example, center environment is replaced with \centering.~~ Using \centering is not necessary, since figure environment centers its contents by default.

\documentclass{beamer}
\usepackage{tikz}
\begin{document}
\begin{frame}{Unitary bounds}
  \begin{figure}
    \begin{tikzpicture}[scale=0.7, every node/.append style={scale=0.7}]
      \fill[red,opacity=.2] (-.5,-1) rectangle (4,3);
      \fill[green!80!black,opacity=.2] (-.5,3) rectangle (4,5);
      \draw[very thick,green!80!black] (-1,3) -- (5,3) node[right, black] {$\Delta=\Delta_A$};
      \draw[very thick, green!80!black] (-1,1) -- (5,1) node[right,black] {$\Delta=\Delta_B$};
      \draw[thick,->] (0,-1) -- (0,5.5) node[right] {$\Delta$};
      \node at (2,2) {non-unitary};
      \node at (2,0) {non-unitary};
      \node at (2,4) {unitary};
    \end{tikzpicture}
    \caption{Unitarity structure of superconformal multiplets.}\label{fig:unitarity}
  \end{figure}
\end{frame}
\end{document}

Something's wrong--perhaps a missing \item. \end{frame}: tikzpicture

1 Answers1