Fix coordinates when using overlayarea in beamer

Question

In this example I am using overlayarea to develop a tikz picture over slides:

\documentclass{beamer}
\usepackage{tikz}
\begin{document}
\begin{frame}
    \begin{overlayarea}{\linewidth}{0.9\paperheight}
      \centering
      \begin{tikzpicture}
        \draw[red, very thick](0, 0) -- (3, 0);
        \only<1>{
          \draw(-1, 1) -- (2, 1);
        }
        \only<2>{
          \draw(-2, 2) -- (1, 2);
        }
      \end{tikzpicture}
    \end{overlayarea}
  \end{frame}
\end{document}

Unfortunately, the coordinate system gets readjusted on each slide as evidenced by the jumping of the red thick anchor line:

How to use the same coordinates on each slide when using overlayarea?

Answer 1

Here is a (admittedly somewhat hacky) style, based on this post, that records the bounding box of a picture, which requires an identifier like A. The key recycle bounding box=<identifier> will record the bounding box to the aux file such that it gets restored in the second run.

\documentclass{beamer}
\usepackage{tikz}
\makeatletter
\tikzset{recycle bounding box/.style={%
execute at end picture={%
\immediate\write\@mainaux{\xdef\string\figbb@#1{%
(\the\pgf@picminx,\the\pgf@picminy) rectangle (\the\pgf@picmaxx,\the\pgf@picmaxy)}\relax}},
execute at begin picture={%
\ifcsname figbb@#1\endcsname
 \edef\figbb{\csname figbb@#1\endcsname}
 \path \figbb;
\fi}}}
\makeatother
\begin{document}
\begin{frame}[t]
      \begin{tikzpicture}[recycle bounding box=A]%<- A is an identifier
        \draw[red, very thick](0, 0) -- (3, 0);
        \only<1>{
          \draw(-1, 1) -- (2, 1);
        }
        \only<2>{
          \draw(-2, 2) -- (1, 2);
        }
      \end{tikzpicture}
  \end{frame}
\end{document}

If you have several pictures the bounding boxes of which you want to record, you need to give each of them a unique identifier. In this regard this works like the eqparbox package. Like in eqparbox you need to run twice. (Note to myself: this style will be very useful for animations.)

You can also draw the picture in the overlay mode

\documentclass{beamer}
\usepackage{tikz}
\begin{document}
\begin{frame}
      \begin{tikzpicture}[overlay,remember picture,shift={(current page.center)}]
        \draw[red, very thick](0, 0) -- (3, 0);
        \only<1>{
          \draw(-1, 1) -- (2, 1);
        }
        \only<2>{
          \draw(-2, 2) -- (1, 2);
        }
      \end{tikzpicture}
  \end{frame}
\end{document}

The problem with this approach is that we need to add the shift by hand. Another reading of the question is answered by

use \path[use as bounding box] ....,

as in

\documentclass{beamer}
\usepackage{tikz}
\begin{document}
\begin{frame}
    \begin{overlayarea}{\linewidth}{0.9\paperheight}
      \centering
      \begin{tikzpicture}
        \path[use as bounding box] (-4,-2) rectangle (4,3);
        \draw[red, very thick](0, 0) -- (3, 0);
        \only<1>{
          \draw(-1, 1) -- (2, 1);
        }
        \only<2>{
          \draw(-2, 2) -- (1, 2);
        }
      \end{tikzpicture}
    \end{overlayarea}
  \end{frame}
\end{document}

The downside is that we need to fix the bounding box by hand. This is what gets avoided by the hack at the beginning of the answer.

I personally use the overlay-beamer-styles library. That way you just make the paths invisible but keep them in such that the bounding box does not change.

\documentclass{beamer}
\usepackage{tikz}
\usetikzlibrary{overlay-beamer-styles}
\begin{document}
\begin{frame}
    \begin{overlayarea}{\linewidth}{0.9\paperheight}
      \centering
      \begin{tikzpicture}
        \draw[red, very thick](0, 0) -- (3, 0);
          \draw[visible on=<1>](-1, 1) -- (2, 1);
          \draw[visible on=<2>](-2, 2) -- (1, 2);
      \end{tikzpicture}
    \end{overlayarea}
  \end{frame}
\end{document}

You can introduce short cuts:

\documentclass{beamer}
\usepackage{tikz}
\usetikzlibrary{overlay-beamer-styles}
\begin{document}
\begin{frame}[t]
\frametitle{Some title}
      \centering% the number of # depends on whether or not you add these
      % definitions in the frame and whether or not your frame is `fragile`.
      \begin{tikzpicture}[vo/.style={visible on=<####1>}]
        \draw[red, very thick](0, 0) -- (3, 0);
          \draw[vo={1}](-1, 1) -- (2, 1);
          \draw[vo={2}](-2, 2) -- (1, 2);
      \end{tikzpicture}
\end{frame}
\end{document}