beamer：让图片停留在前景中

Question

我正在尝试为海报框架编写一些样式文件，以供我们使用。标题几乎已准备就绪：

\setbeamertemplate{headline}
{
  \begin{beamercolorbox}[ht=15cm]{headline}
    \begin{tikzpicture}[overlay, remember picture]
    %title text
      \node [anchor=north west,inner sep=0pt,text width=60cm] at ($(current page.north west)+(4.5cm,-2.8cm)$)
    {
    {\usebeamerfont{title}\usebeamercolor{headline}\color{fg}\inserttitle\par}%
    \ifx\insertsubtitle\@empty%
    \else%
        \vskip28mm\par%
        {\usebeamerfont{subtitle}\usebeamercolor{headline}\color{fg}\insertsubtitle\par}%
    \fi%
    %{\usebeamerfont{subtitle}\usebeamercolor{headline}\color{fg}\insertauthor\par}%
    %   {\usebeamerfont{institute}\usebeamercolor{headline}\color{fg}\insertinstitute\par}              
    };
    %hzdr logo
    \node [anchor=north east,inner sep=0pt] at ($(current page.north east)-(2cm,2.8cm)$)
    {\includegraphics[width=22.39cm,hiresbb]{HIF_E_weiss_auf_transparent}};
    %
    \node [anchor=north east, inner sep=0pt] at ($(current page.north east)-(-3cm,13cm)$)
    {\includegraphics[hiresbb]{PIKTO_ENGL_300DPI21}};
    \end{tikzpicture}
 \end{beamercolorbox}
}

最后一张图超出了实际的标题。它应该是可见的，即应该留在前景中，无论在海报的标题下添加什么。海报主要由其他 beamercolorboxes 组成：

\newcommand\posterblock[4][]
{
\fcolorbox{hzdr-blue}{white}{
    \begin{beamercolorbox}[colsep*=1ex,#1]{bgblock}%use bigger values for colsep* if you want to make the box around the text bigger;warning: if you use the option rounded this will disable the horizontal spaces around the text
        \begin{block}{\usebeamerfont{block title}#2}\justify
            {\usebeamerfont{small block title}\color{hzdr-blue}{#3}}\vspace{2ex}

            {\usebeamerfont{block body}#4}
        \end{block}
    \end{beamercolorbox}}
    \quad
}

但是当我使用这个海报块时，它总是在图片上方。有人能帮忙让图片保持在前景吗？

Answer 1

Beamer 将不同的框架组件层叠放置：

[图片借自https://tex.stackexchange.com/a/27302/36296，请参阅此处了解更多信息]

如果您希望图像位于顶部，请选择适当的图层，例如脚注。

\documentclass{beamer}

\setbeamertemplate{footline}{%
    \begin{picture}(0,0)
        \put(0,95){\includegraphics[width=3cm]{example-image}}
    \end{picture}   
}

\begin{document}
  \begin{frame}
        Bla
  \end{frame} 
\end{document}