更改垂直对齐中框

Question

我有三个要点，我想在一帧上连续地提出，一张一张地展示。第二点需要澄清一下，所以我想插入一张包含这个要点的幻灯片，以及关于它的注释。三个要点居中对齐，但这个注释可能相当长，所以我想将包含注释的幻灯片顶部对齐（与选项一样[t]）。理想情况下，我希望所有这些都发生在一页上。也就是说，页码不会在任何这些幻灯片中增加。

最小工作示例：

\documentclass{beamer}

\usetheme{Ilmenau}

\begin{document}

\begin{frame}
    \begin{onlyenv}<-2,4->
        \begin{block}{Block One}
            This is my first block.
        \end{block}
    \end{onlyenv}
    \begin{onlyenv}<2->
        \begin{block}{Block Two}
            This is my second block.
        \end{block}
    \end{onlyenv}
    \begin{onlyenv}<3>
        \begin{block}{Note}
            This is a really long note about block two that takes several lines.
            When it appears on slide 3 the entire frame should be top aligned,
            rather than centered as on slides 1, 2, and 4.
        \end{block}
    \end{onlyenv}
    \begin{onlyenv}<4->
        \begin{block}{Block Three}
            This is my third block.
        \end{block}
    \end{onlyenv}
\end{frame}

\end{document}

为了更加明确，我希望Block One在幻灯片 1 中单独居中显示。在幻灯片 2 中，Block One和Block Two应该居中显示。幻灯片 3 应包含Block Two和Note 顶部对齐，然后幻灯片 4 应包含Block One、Block Two和Block Three，再次居中。

我尝试创建另外两个框架来代表幻灯片 3 和 4，但这样会产生大量重复代码，而且我似乎也无法协调页数。我也尝试过\againframe只为第三张幻灯片创建框架，但遇到了同样的问题。

Answer 1

您可以使用[t]op 对齐框架并\vfill在所有覆盖层的顶部插入一个应居中的：

\documentclass{beamer}

\usetheme{Ilmenau}

\begin{document}

\begin{frame}[t]
    \only<1,2,4>{\vfill}
    \begin{onlyenv}<-2,4->
        \begin{block}{Block One}
            This is my first block.
        \end{block}
    \end{onlyenv}
    \begin{onlyenv}<2->
        \begin{block}{Block Two}
            This is my second block.
        \end{block}
    \end{onlyenv}
    \begin{onlyenv}<3>
        \begin{block}{Note}
            This is a really long note about block two that takes several lines.
            When it appears on slide 3 the entire frame should be top aligned,
            rather than centered as on slides 1, 2, and 4.
        \end{block}
    \end{onlyenv}
    \begin{onlyenv}<4->
        \begin{block}{Block Three}
            This is my third block.
        \end{block}
    \end{onlyenv}
\end{frame}

\end{document}