Beamer: Transparent cover previous and following items

Question

The LaTeX Beamer class offers a transparent overlay (\setbeamercovered{transparent}) which makes the following items a bit transparent. The items that were already shown stay at full opacity. In order to focus the listener's attention on the current item, I would prefer to have both the following and the already discussed items made transparent and only the current point displayed with full opacity.

---

Slide 1

- Foo
- Bar (opacity: 0.5)
- Ham (opacity: 0.5)
- Eggs (opacity: 0.5)

Slide 2

- Foo (opacity: 0.5)
- Bar
- Ham (opacity: 0.5)
- Eggs (opacity: 0.5)

Slide 3

- Foo (opacity: 0.5)
- Bar (opacity: 0.5)
- Ham
- Eggs (opacity: 0.5)

Slide 4

- Foo (opacity: 0.5)
- Bar (opacity: 0.5)
- Ham (opacity: 0.5)
- Eggs

---

How could I achieve this?

Answer 1

You can highlight the current item only with [<+>]:

\documentclass{beamer}

\setbeamercovered{transparent}

\begin{document}

\begin{frame}
\begin{itemize}[<+>]
\item Duck
\item Marmot
\item Sloth
\item Bear
\end{itemize}
\end{frame}


\end{document}

---

And a little experiment just for fun:

\documentclass{beamer}

\setbeamercovered{transparent}
\usepackage{tikzducks,tikzlings}

\begin{document}

\begin{frame}
\begin{itemize}[<+>]
\item \alt<.>{\tikz[scale=0.2]{\duck}}{Duck}
\item \alt<.>{\tikz[scale=0.2]{\marmot}}{Marmot}
\item \alt<.>{\tikz[scale=0.2]{\sloth}}{Sloth}
\item \alt<.>{\tikz[scale=0.2]{\bear}}{Bear}
\end{itemize}
\end{frame}


\end{document}