[Tex/LaTex] redefine \includegraphics for beamer

beamergraphicspandoc

I'm using Pandoc to convert from markdown to LaTeX or Beamer.
The LaTeX template of Pandoc has nice command so that images are resized to fit the text width but the Beamer output is not.

\makeatletter
\def\maxwidth{\ifdim\Gin@nat@width>\linewidth\linewidth
\else\Gin@nat@width\fi}
\makeatother
\let\Oldincludegraphics\includegraphics
\renewcommand{\includegraphics}[1]{\Oldincludegraphics[width=\maxwidth]{#1}}

So I tried to copy the commands to the Beamer template, but then it gives an error while compiling with pdflatex.
I checked the preamble but couldn't figure out which one is incompatible. Maybe beamer class itself is the problem?

Here is my sample beamer code.

\documentclass[ignorenonframetext,]{beamer}
\usepackage{amssymb,amsmath}
\usepackage{ifxetex,ifluatex}
\usepackage{fixltx2e} % provides \textsubscript
\ifxetex
  \usepackage{fontspec,xltxtra,xunicode}
  \defaultfontfeatures{Mapping=tex-text,Scale=MatchLowercase}
\else
  \ifluatex
    \usepackage{fontspec}
    \defaultfontfeatures{Mapping=tex-text,Scale=MatchLowercase}
  \else
    \usepackage[utf8]{inputenc}
  \fi
\fi

\usepackage{graphicx}
\makeatletter
\def\maxwidth{\ifdim\Gin@nat@width>\linewidth\linewidth
\else\Gin@nat@width\fi}
\makeatother
\let\Oldincludegraphics\includegraphics
\renewcommand{\includegraphics}[1]{\Oldincludegraphics[width=\maxwidth]{#1}}
% Comment these out if you don't want a slide with just the
% part/section/subsection/subsubsection title:
\AtBeginPart{\frame{\partpage}}
\AtBeginSection{\frame{\sectionpage}}
\AtBeginSubsection{\frame{\subsectionpage}}
\AtBeginSubsubsection{\frame{\subsubsectionpage}}
\setlength{\parindent}{0pt}
\setlength{\parskip}{6pt plus 2pt minus 1pt}
\setlength{\emergencystretch}{3em}  % prevent overfull lines
\setcounter{secnumdepth}{0}


\begin{document}

\begin{frame}\frametitle{Introduction}

Testing image size from R saved by various methods.

\end{frame}

\begin{frame}\frametitle{Results}

All images were set width = 7. For ggsave, the dpi =300.

\begin{block}{Saved by ggsave}

\begin{figure}[htbp]
\centering
\includegraphics{./plot_by_ggsave.pdf}
\caption{Saved by ggsave}
\end{figure}

\end{block}
\end{frame}

\end{document}

Best Answer

The beamer class redefines \includegraphics, but "at begin document", so your redefinition must be given at the same time:

\usepackage{letltxmacro}
\makeatletter
\def\maxwidth{\ifdim\Gin@nat@width>\linewidth\linewidth\else\Gin@nat@width\fi}
\makeatother
\AtBeginDocument{
  \LetLtxMacro\Oldincludegraphics\includegraphics
  \renewcommand{\includegraphics}[2][]{%
    \Oldincludegraphics[#1,width=\maxwidth]{#2}}
}

See the documentation of letltxmacro for understanding why \LetLtxMacro is needed.

Related Solutions

[Tex/LaTex] Redefine block template for Beamer theorem-like environment

You can set the theorem begin and theorem end templates to use an exampleblock:

\documentclass{beamer}
\usetheme{CambridgeUS}

\makeatletter
\setbeamertemplate{theorem begin}
{%
  \begin{exampleblock}
  {%
%    \inserttheoremheadfont% uncomment if you want amsthm-like formatting
    \inserttheoremname
    \inserttheoremnumber
    \ifx\inserttheoremaddition\@empty\else\ (\inserttheoremaddition)\fi%
    \inserttheorempunctuation
  }%
}
\setbeamertemplate{theorem end}{\end{exampleblock}}
\makeatother

\begin{document}

\begin{frame}
\begin{definition}
Test text.
\end{definition}
\begin{exampleblock}{Definition}
(Definition here)
\end{exampleblock}
\end{frame}

\end{document}

enter image description here

The above solution makes all theorem-like environments inherit the settings for exampleblock; if just the default definition environment must behave like exampleblock, all one has to do is to change the default style used for definition to make it equal to the example style; a simple way to achieve this is to \let both commands \definition and \enddefinition to \relax and then use \newtheorem to define the definition structure using the example style.

An example showing this approach; definition behaves as an exampleblock, but all other theorem-like structures preserve theis default behaviour:

\documentclass{beamer}
\usetheme{CambridgeUS}

\let\definition\relax
\let\enddefinition\relax

\theoremstyle{example}
\newtheorem{definition}[theorem]{\translate{Definition}}

\begin{document}

\begin{frame}
\begin{definition}
Test text.
\end{definition}
\begin{exampleblock}{Definition}
Test text.
\end{exampleblock}
\begin{theorem}
Test text.
\end{theorem}
\end{frame}

\end{document}

enter image description here

[Tex/LaTex] Loop for includegraphics

You can define a PGF array and access it via \pgfmathparse, the array index starts from 0 instead. I've used a,b,c for convenience.

EDIT: Added a general content loop but still it is not that economic on verbosity.

\documentclass{beamer}
\usepackage{tikz,etoolbox}
\usepackage{mwe} %<- for dummy images

\begin{document}

\def\fnames{a,b,c}
\def\tnames{{"white","gray","black"}}


\foreach \x[count=\xcount from 0] in \fnames {%
\def\myframecontents{}
\foreach\y in{1,2,3}{
    \gappto\myframecontents{%
        \column{0.33\textwidth}%
        \includegraphics[width=4.cm]{example-image-\x}%
    }
}

\pgfmathparse{\tnames[\xcount]}
\begin{frame}{\pgfmathresult}
   \begin{columns}    
       \myframecontents
   \end{columns} 
\end{frame}%
}
 \end{document}

enter image description here

Best Answer

Related Solutions

[Tex/LaTex] Redefine block template for Beamer theorem-like environment

[Tex/LaTex] Loop for includegraphics

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