# Beamer keeping line position constant on itemize

I want to have a slide in beamer with itemize exposing new line on each click while at the bottom part of the slide there are some equations. This is my attempt

\begin{frame}
\begin{overprint}{\textwidth}
\leavevmode
\begin{itemize}[<+->]
\item <1-> Poisson Boltzman equation (PB)
\item <2-> Debye-H\"uckle equation  (DH)
\item <3-> The naive approach - applying (DH) equation to PE
\end{itemize}
\end{overprint}
\begin{tikzpicture}
\node at (0,0) {};
\node<1,2> [text width = 20cm]at (10.5,-1) {$\nabla^2 \phi =\sum_i \frac{n_i q_i\text{e}^{-q_i \phi/kT}}{4 \pi \epsilon}$};
\node <2> [text width = 20cm]at (10.5,-2) {$q_i \phi/kT \ll 1 \Rightarrow \nabla^2 \phi \simeq \kappa^2 \phi$};
\node <2> [text width = 20cm, font=\footnotesize]at (10.5,-2.5) {$\kappa^2 = \lambda^{-1/2} = \sum_i \frac{n_i q_i}{4 \pi \epsilon}$};
\node <3> [text width = 20cm] at(10.5,-1) {$\frac{F_{el}}{VkT} = - \left ( \frac{ 4 \pi e^2}{\epsilon kT} \sum_{i=1} n_i z_i^2 \right )^{3/2} \left ( 12 \pi \right )^{-1}$};
\end{tikzpicture}
\end{frame}


However, the itemized line jump up and down between slides. I've tried to use itemize without any environment surrounding it. I've also tried to use overlayarea instead of overprint. How can I keep the line position constant? I've uploaded a gif animation to display this. On my machine it run really fast and I can't fix this. Hope the problem is understood.

When I run this, I get • Include also the tikzpicture in the overprint helps? – Claudio Fiandrino Jul 9 '13 at 13:43

One possibility with overlayarea:

\documentclass{beamer}
\usepackage{tikz}

\begin{document}

\begin{frame}
\begin{overlayarea}{\textwidth}{.6\textheight}
\begin{itemize}[<+->]
\item <1-> Poisson Boltzman equation (PB)
\item <2-> Debye-H\"uckle equation  (DH)
\item <3-> The naive approach - applying (DH) equation to PE
\end{itemize}
\begin{tikzpicture}
\node at (0,0) {};
\node<1,2> [text width = 20cm]at (10.5,-1) {$\nabla^2 \phi =\sum_i \frac{n_i q_i\text{e}^{-q_i \phi/kT}}{4 \pi \epsilon}$};
\node <2> [text width = 20cm]at (10.5,-2) {$q_i \phi/kT \ll 1 \Rightarrow \nabla^2 \phi \simeq \kappa^2 \phi$};
\node <2> [text width = 20cm, font=\footnotesize]at (10.5,-2.5) {$\kappa^2 = \lambda^{-1/2} = \sum_i \frac{n_i q_i}{4 \pi \epsilon}$};
\node <3> [text width = 20cm] at(10.5,-1) {$\frac{F_{el}}{VkT} = - \left ( \frac{ 4 \pi e^2}{\epsilon kT} \sum_{i=1} n_i z_i^2 \right )^{3/2} \left ( 12 \pi \right )^{-1}$};
\end{tikzpicture}
\end{overlayarea}

\end{frame}

\end{document} By the way, your syntax for overprint is wrong; the width should be declared as an optional argument:

\begin{overprint}[<width>]
...
\end{overprint}

• Thanks. What does the {.6\textwidth} stand for? I'm trying to do this on another slide with terrible results. Also, I had to place the tikz part inside the overlayarea otherwise it ran off the screen. – Yotam Jul 9 '13 at 14:09
• @Yotam the first mandatory argument for overlayarea is the reserved width; the second mandatory argument is the reserved height. As you can see in my example, the tikzpicture is inside the overlayrea. – Gonzalo Medina Jul 9 '13 at 14:12
• Sorry, didn't notice that. My tikz part run down even when inside the overlayarea I had to update its y positions. – Yotam Jul 9 '13 at 14:15
• @Yotam Depending on your actual contents, you can change the reserved height; for example, using \textheight in the second argument will reserve the whole text height for the overlayarea material. – Gonzalo Medina Jul 9 '13 at 14:16
• What does the number .6 mean? Is it an estimate of the proportion of page remaining? – user4417 Dec 8 '19 at 10:05