Slide for animation with beamer an TikZ

Question

With the commands \pause of beamer and \foreach of tikz together is possible to create slides that work as layers for an animation in video.

For example:

\documentclass{beamer}
\usepackage{pgf,tikz}

\begin{document}

\begin{frame}[fragile]
    \begin{tikzpicture}
        \foreach \x in {1,2,...,4}{
            \only<\x>{
                \clip (0,0) rectangle (8,4.5);
                \draw[line width=6pt] (0,0) rectangle (8,4.5);
                \fill (2*\x,\x) circle  (.2); % animated object
            }
        }
    \end{tikzpicture}
\end{frame}

\end{document}

I would like to create a new environment as follows:

\documentclass{beamer}
\usepackage{pgf,tikz}

\newenvironment{animation}[1]{
    \begin{frame}
    \begin{tikzpicture}
        \foreach \x in {1,2,...,#1}{
            \only<\x>{
}{
            }
        }
    \end{tikzpicture}
    \end{frame}
}

\begin{document}


\begin{animation}{4}
    \clip (0,0) rectangle (8,4.5);
    \draw[line width=6pt] (0,0) rectangle (8,4.5);
    \fill (2*\x,\x) circle  (.2);
\end{animation}

\end{document}

But doing it this way doesn't work. Would anyone know how this can be done? Whether it can be done?

Answer 1

Try with \NewDocumentEnvironment:

\documentclass{beamer}
\usepackage{pgf,tikz}
\NewDocumentEnvironment{animation}{m +b}{
    \begin{frame}
    \begin{tikzpicture}
        \foreach \x in {1,2,...,#1}{
            \only<\x>{#2}
        }
    \end{tikzpicture}
    \end{frame}
}{}  


\begin{document}
\begin{animation}{4}
    \clip (0,0) rectangle (8,4.5);
    \draw[line width=6pt] (0,0) rectangle (8,4.5);
    \fill (2*\x,\x) circle  (.2);
\end{animation}
\end{document}