[Tex/LaTex] beamer: Difference between \setbeamertemplate{background canvas} and \usebackgroundtemplate (and \setbeamertemplate{background})

beamer

Question

When I want to change the background of a beamer presentation I used to use something like this:

\setbeamertemplate{background canvas}%
{%
    \includegraphics[width=\paperwidth, height=\paperheight]%
    {%
        Picture.jpg
    }%
}

which is also documented in the beamer documentation. In some answers here I often see

\usebackgroundtemplate{
    \includegraphics[width=\paperwidth,height=\paperheight]{Picture.jpg}
}

Is there a best practice?
Surprisingly I can't find \usebackgroundtemplate when searching in the beamer documentation.

What is difference between template's `background` and `background canvas`? (I added \setbeamertemplate{background} so that the question title is more complete)

Best Answer

Concerning your questions what \usebackgroundtemplate does:

It's defined in beamerbasecompatibility.sty as
```
\def\usebackgroundtemplate{\setbeamertemplate{background canvas}}
```
From the filename I would conclude, that commands defined for compatibility are not the ones to be used as "best practice" - but the result should be the same.
For the difference of \setbeamertemplate{background canvas} and \setbeamertemplate{background}:

Basically these are two different layers, see How does beamer build the frame? for an overview.

Related Solutions

Beamer Backgrounds – Adding Rectangles to Background Canvas

Hi some thing like this could help:

\documentclass{beamer} 

\title{Stackxchng} 
\author{McCool} 
\institute{sth}
\date{the day the music died}   



\begin{document} 

\setbeamercolor{my thing}{fg=red, bg=black}% you can use every beamer color 
 \setbeamertemplate{title page}
   { 
\begin{beamercolorbox}[ht=2cm,wd=\paperwidth, left, sep=.5cm]{my thing}
 \color{black}Upper % use every color you want
\end{beamercolorbox}%
\vskip0pt plus 1filll % see beamerusersguide

\begin{centering} % some Text Macros
 \inserttitle 

  \insertsubtitle 

 \insertauthor 

 \insertdate 

  \insertinstitute 

   \inserttitlegraphic
\end{centering}
\vskip0pt plus 1filll % again tantau magical
\leavevmode \begin{beamercolorbox}[ wd=\paperwidth, ht=2cm, sep=.5cm]{my thing}
  \color{black} Lower % or what ever you like
\end{beamercolorbox}%
}



\frame[plain]{\titlepage} % PLAIN!
\frame{just a frame}
\end{document}

Hope that helps

Beamer – How to Place Images Behind Text (z-order)

You can define a custom environment backgroundblock like this:

\documentclass{beamer}

% For demonstration purposes only, can be removed without harm
\usetheme{Ilmenau}
\usepackage{lipsum}

% beamer: How to place images behind text (z-order)
% (http://tex.stackexchange.com/a/134311)
\makeatletter
\newbox\@backgroundblock
\newenvironment{backgroundblock}[2]{%
  \global\setbox\@backgroundblock=\vbox\bgroup%
    \unvbox\@backgroundblock%
    \vbox to0pt\bgroup\vskip#2\hbox to0pt\bgroup\hskip#1\relax%
}{\egroup\egroup\egroup}
\addtobeamertemplate{background}{\box\@backgroundblock}{}
\makeatother

\begin{document}
\begin{frame}
\begin{backgroundblock}{10mm}{10mm}
\includegraphics[width=50mm]{example-image-a}
\end{backgroundblock}
\lipsum
\begin{backgroundblock}{60mm}{47.5mm}
\includegraphics[width=50mm]{example-image-b}
\end{backgroundblock}
\end{frame}
\end{document}

It is used very much like the textpos environment textblock(*) in absolute mode, i. e.

\begin{backgroundblock}{<hpos>}{<vpos>}
<Content>
\end{backgroundblock}

places <Content> in a box at the coordinates (<hpos>,<vpos>) relative to the top left corner of the slide.

example slide with two backgroundblock environments

Explanation of the code

A box \@backgroundblock is added to the beamer template background which is later filled by the content of the backgroundblock environments. This shouldn't interfere with custom themes, as it is ensured that the box doesn't any occupy any space.