Generate Beamer Slides From Org Mode

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Introduction

I have been using pandoc (from John Macfarlane) to generate PowerPoint slides. I have documented this here.

For specific projects, where the presentations had to include mathematical formulas, footnotes and citations, I decided to generate "Beamer" slides from org-mode source documents.

Summary

"Beamer" slides are PDF files, which are generated using the LaTeX system.

org-mode has an out-of-the-box beamer export module. Hence Emacs and LaTeX is all you need to generate beamer slides

I have documented below my settings, customisations and observations. You can download the file ./org2beamer.zip to see my test and configuration files.

Prerequisites

I use the "texlive" TeX/LaTeX software. I installed the following Debian packages:

texlive: This is not the full TeX/LaTeX set, but sufficient, except for the next item
texlive-latex-extra: is needed because of wrapfig.sty, which is required by the org-mode exporter (Emacs v28.2 org-mode v9.5.5)
cm-super: makes sure you get decent looking "type 1" fonts included in the output PDF document. By default you get "type 3" bit-mapped fonts which do not look smooth
texlive-lang-german: because I write in german and english
texlive-latex-recommended-doc: to have documentation available locally
inkscape: TeX/LaTeX cannot directly deal with scalable vector graphics (SVG) but it calls inkscape automatically to support SVG

I put in init.el

;;; Beamer export
(require 'ox-beamer)

to have the beamer export option show in the org-mode exporter front-end.

Manifest

The file org2beamer.zip contains the following files:

README.txt	txt version of this web-page
test.org	Test org-mode source file
test.pdf	Resulting beamer output PDF slides
test.tex	Resulting intermediate LaTeX file
mysetup-bmr-169-ysctn.org	Org set-up file
myAddUTF8.tex	LaTeX symbol definitions
redetho-logo1.svg	Test logo
blind_*.svg	Test vector graphics file
blind_*.jpg	Test image files
lit.bib	Test BibTeX file for citations
mysetup-bmr-169-nsctn.org	Org set-up file when not using sections

The files are provided as is. I do not take any responsibility nor provide any warranty.

Installation

Unzip ./org2beamer.zip to any convenient directory
You might want to copy mysetup-bmr-169-ysctn.org to your home directory. If you choose a different location, please amend the path in the first line of test.org
You might want to copy myAddUTF8.tex to ~/texmf/. If you choose a different location, please amend the line
```
#+LATEX_HEADER: \input{~/texmf/myAddUTF8}
```
in file mysetup-bmr-169-ysctn.org

Test Usage to Generate a Beamer-PDF-File

Open test.org in Emacs
Export to a beamer PDF file by pressing C-c C-e l P, which runs the command org-beamer-export-to-pdf
View the resulting file test.pdf using your favourite PDF-viewer. Please note that the ZIP archive also contains a result file test.pdf and the intermediate file test.tex for your reference. You might want to rename those two before

While the C-c C-e standard org-mode exporter is fine for tests and occasional exports, I use a Makefile for more complex projects. That Makefile would typically contain (covers both Windows and Linux):

ifeq ($(OS),Windows_NT)
	EMACSCL=$(MYPROGPATH)/emacs-27.2/bin/emacsclientw.exe
else
	EMACSCL=emacsclient
endif

test.pdf:	test.org $(HOME)/mysetup-bmr-169-ysctn.org
	$(EMACSCL) --eval "(find-file \"test.org\")" \
	 "(org-beamer-export-to-pdf)"

Using Org-Mode's SETUPFILE Mechanism for Configuration

The file test.org contains the slide content and essential meta data. It references the file mysetup-bmr-169-ysctn.org using org-mode's #+SETUPFILE: mechanism. mysetup-bmr-169-ysctn.org configures the org-mode beamer exporter and contains LaTeX and Beamer settings. The key settings are:

16:9 slide aspect ratio
Section divider slides shall be used

Obviously, different key settings require different set-up files, hence the names of the set-up files. I include in the ZIP archive the file mysetup-bmr-169-nsctn.org which is meant for shorter presentations that do not need section divider slides.

Please read below for details about slide format customisation, which is also effected by the set-up file.

Observations

Note that some of the issues discussed below are LaTeX/Beamer issues. However, I discuss them here because I collected solutions for them from various documentation pieces or from the internet.

I also document how these issues can be addressed directly from the org-mode source code or the setup-file which gets included by the org-mode source file.

Tables

So far I did not need to change the table settings from the defaults.

Links

When you want to generate a link in a beamer presentation to a PDF document from org-mode, you need to provide a description, like so

[[./file.pdf][Description]]

If you omit the description, like

[[./file.pdf]]

the first page of the PDF document gets embedded in the output beamer PDF file.

Language Support

For non-English language texts, you would add

#+LANGUAGE xx

to your org-mode text, where xx is the ISO language code. The org-mode exporter will add that language to the

\usepackage[shorthands=off,english]{babel}

statement from the set-up file. The desired language gets added after the english babel option in the intermediate .tex file. Hence it will become the "start" language used for the slides.

However: The table of contents will always read "Outline".

Support for special characters

The set-up file includes the statement

#+LATEX_HEADER: \input{~/texmf/myAddUTF8}

The file myAddUTF8.tex is included in the ZIP-file. It contains LaTeX definitions for additional UTF-8 characters you could use directly in the org-mode main file. I chose to store myAddUTF8.tex in the texmf sub-directory of my home directory.

Images - Scaling

The file test.org shows how to scale images. I found that scaling relative to the LaTeX paperheight works best for slides, both for 16:9 and 4:3 aspect ratios. However, for LaTeX article documents I usually scale relative to paperwidth, as article has portrait aspect ratio.

Images - Multiple on a page

Beamer allows for fine grained control of how to use the slide real estate of individual slides, e.g. when placing multiple images on a slide. However, I have not yet needed that functionality.

Scalable Vector Graphics (SVG) Text Issues

When referencing SVG files to be included in the PDF-slides, inkscape is being run automatically in the background, to help LaTeX/beamer deal with SVG.

By default text elements (text objects), which are contained in the SVG files, would be processed by LaTeX/Beamer. E.g. an underscore would switch to subscript. Usually, this is not what you want. To prevent this, the set-up file contains the line

#+LATEX_HEADER: \svgsetup{inkscapelatex=false}

Various Beamer Slide Format Customisations

The set-up file mysetup-bmr-169-ysctn.org contains various customisations, how the generated slides shall look like. The customisations are applied to the default LaTeX/beamer "theme" (theme is a beamer term for a defined slide layout). These are my personal preferences:

Everything shall be top-aligned vertically. The default is centered
The title page shall have everything left aligned horizontally. The default is centered
The bullet glyphs for enumerations level 1 to 3 are set explicitly
Navigation symbols are switched off
The fonts are set to be bfseries (sans serif)
All colours are set to black, except for hyperlinks which are set to blue
I define a specific footer. Note that a logo is set in the test.org main org file, rather than the set-up file, because I need different logos for different projects

Covered Functionality

The org-mode built-in exporter for Beamer slides supports the full org functionality, like macro support and org babel support.

When using Pandoc instead, you might want to try the ox-pandoc package, to be able to use most of org's functionality and use Pandoc for additional target formats like PowerPoint.

Other

I trust you notice that mysetup-bmr-169-ysctn.org also contains org-mode in-buffer customisations for HTML export and text export. I have written about HTML export here

You might also be interested in LaTeX article generation from org-mode or using pandoc together with org-mode.