Org Mode Beamer Presentations

Earlier I talked about using Org Mode to produce lesson worksheets for my students. This year I am thinking about using powerpoint-style presentation slides instead of worksheets to encourage students to write more in their books. This naturally led me to look into how to do this with Org Mode.

A Simple Lesson

Making presentations in \(\LaTeX\) is normally done using the beamer package. It turns out that Org Mode has good support for beamer. An example of a simple lesson presentation org-mode file might look like this:

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#+title: Adding Terms
#+subtitle: Algebraic Techniques
#+author: Mr Maguire
#+startup: beamer
#+options: H:1 toc:nil
#+latex_class: beamer
#+latex_class_options: [bigger]
#+columns: %45ITEM %10BEAMER_env(Env) %10BEAMER_act(Act) %4BEAMER_col(Col) %8BEAMER_opt(Opt)
#+beamer_theme: SimplePlus
#+LATEX_HEADER: \usepackage{tasks}

* DO NOW
1. Identify the like terms:
   \[ 4ab^2, 4ab, 2a^2b^2, 3b^2a \]
   \vskip+5ex
2. Which is the constant term?
   | 3x | 4x^2 | 5x^0 | x |

* Adding Terms
To add terms:
- make sure the two terms are *like* terms
- add the coefficients

** Careful! :B_block:
Don't forget to take any minus signs into account!

* Practice
Simplify the following espressions
\begin{tasks}[after-item-skip=8ex](2)
\task $2x+3x$
\task $3a+5b+6a$
\task $a+b+2b+a$
\task $a^{2}+2ab-2ba+b^{2}$
\task* $a+2a-3a+4a-5a+6a-7a+8a-9a+10a$
\end{tasks}

* :B_ignoreheading:
#+begin_center
*What's $2n$ plus $2n$?*
\vskip+2ex
I don't know, it sounds $4n$ to me...
#+end_center

To export the org mode code to a PDF, we need to use a special export command to let org-mode know to make a beamer presentation rather than a normal \(\LaTeX\) document. On my system, the export process is bound to C-c C-e l O which will:

• translate the org mode to a \(\LaTeX\) *.tex file
• produce a PDF file from the \(\LaTeX\) file
• open the PDF file in Emacs (I have pdftools installed in my Emacs config)

If I want to generate the PDF file without opening it (for example, if I already have the PDF file open in another window) then I use the key sequence C-c C-e l P.

This will then produce a PDF file that looks like this:

Preamble

So, let’s break down the contents of the preamble in the org mode file:

• The #+title:, #+subtitle:, #+author: and optionally #+date: are self-explanatory and are used to generate the title slide.
• The #+startup: beamer line tells Emacs that this is a beamer org-mode file and that it should enable the special org mode beamer minor mode for syntax highlighting, etc.
• The #+options: H:1 toc:nil line tells org mode that I don’t want a table of contents slide, and that each level 1 heading in the org file should represent a new slide. If I put H:2 instead, then level 1 headings would represent sections with a section heading slide, and the level 2 headings would be the actual content slides. I want to minimise that extra fluff for my students so that we can focus purely on content, and this is why I use H:1
• The #+latex_class: beamer line uses the predefined Org Mode beamer class, and the #+latex_class_options: [bigger] sets a larger font size to help students make out the slides more clearly. Font size can be overridden for a particular slide using the \fontsize{}{} command at the start of that slide’s content.
• The #+columns: line enables a cool “column mode feature” in Emacs Org Mode. I don’t want to discuss it here, but you can read mode about this in the Org Mode manual .
• The #+beamer_theme: line sets the “look and feel” of the slides. I use a fairly simple theme to minimise cognitive load for the students. You can find other themes on the internet, such as at this site .
• You can then include any packages you might want to use with lines like #+latex_header: \usepackage{}. You can see I use the tasks package, which lets you easily format multi-column lists of problems like I did with the exesheets package in the org mode lesson notes post.

Content

Now that we have set up the environment, we can start making some slides!

1. The first slide I have is a “DO NOW” starter activity. The text in the level 1 heading becomes the title at the top of the slide. In the example, I have a simple enumerated list. You can see we can include maths notiation using the normal "$ ... $" and "\[ ... \]" markers. Sometimes it is better to use "\( ... \)" delimiters for inline maths expressions, as the dollar signs can be confused with currency symbols. If you want to write dollar signs in an expression, you can use a \dollar or \USD command.
2. The second slide shows a bullet list. You can also use standard org-mode markup for bold text, italics, etc.. It also includes a highlighted text box, which you can create using a subheading marked with a :B_block: tag.
3. The third slide makes use of the tasks package. The org mode beamer export filter doesn’t work well with that package, so I find the easiest thing is to simply use \(\LaTeX\) code. You can then easily specify separation between the items with after-item-skip and how many columns of questions we want. Each question is introduced with a \task command, and if you want a longer question to span all the columns we can use \task* with an asterisk.
4. The last slide shows how we can create a slide with no title. You can also use a \(\LaTeX\) environment such as \begin{center} ... \end{center} using the #+begin_center ... #+end_center directives. If we want to create some white space where we can write answers or annotate a solution, we can use a command like \vskip+2ex to create that vertical space.

Further Reading

This is a very quick introduction. If you want to learn more, I suggest you look at:

• A org mode beamer tutorial which was the main basis of the simple example I provided here.
• The org mode beamer user manual