Example lesson

How to teach using org-mode for fun and profit

Olivier Berger

2018-04-23

Introduction

This is a demo document about the codename org-teaching framework, which aims at managing teaching material using Org-mode.

This is a HTML slides deck

  • You're viewing a reveal.js Web slides deck. You may press 's' to view presenter notes.

Org-mode powa

Attention, this framework heavily relies on:

About this slides deck

These slides are one variant of the same teaching material, also available as a PDF handbook.

You may prefer to view them in your Web browser in full-screen (F11 for instance). Should Reveal-JS fail on displaying slides, an alternate format would be the printed PDF (but you're gonna lose the ability to display speaker notes).

Features

Writing teaching material in org-mode

The goal is to be able to edit a single file (namely lesson.org) which will contain, in a single source, all the content of a lesson, written with org-mode syntax.

From this single source, several documents are generated :

  • slides (as a dynamic Web document) for overhead presentation
  • a handbook that contains the same information (or more) and can be handed to the students for work outside the classroom (a PDF file)
  • optionaly, another version of the handbook for the teaching team, to provide additional instructions (also a PDF file)

Frugal org-reveal/reveal.js slides

Pretty much all features of reveal.js, supported by the org-mode reveal.js exporter (org-reveal), should be supported too.

If you're already familiar with reveal.js, you may have noticed that the current settings adopted for our slides generation are quite frugal: no fancy 3D effects and likes.

Structure of the sections / slides

I'm using the 3 levels of outlining / sectioning so that the content can be sectioned in the same way in lesson.org and appear appropriately in the slides and handbook, with these principles:

  1. First level outlines define main sections of the document.
  2. Second level outlines are the main "horizontal" slides that will be played with page up/down
  3. Third level outlines may be used for additional content ("vertical" slides) that may be skipped for the presentation, but is still accessible with cursor keys.

Presenter notes / content for the handbook

org-reveal's Speaker notes may be added to the slides (and will only appear on dual-screen presentation after having pressed 's': standard reveal.js feature).

They will be masked for the audience, but will, by default, appear in the handbook given to the students.

The syntax in the org-mode source is:

#+BEGIN_NOTES
This is a note
#+END_NOTES

Masking content for some audiences

I've implemented some "easy ways" to preserve some of the content of the same lesson.org source for certain outputs (using org exporter's standard EXCLUDE_TAGS):

Slides only material
that won't be embedded in the handbook : surprise stuff for live audience, or HTML-only hacks;
Teachers only material
secret knowledge that only adults need to know (for instance), which won't be exported;
Handbook only material
stuff that only fits in the handbook, and/or only exports as LaTeX and not HTML.

Stuff only meant for presentation

Tagging a section/slide with :slidesonly: means it isn't exported in the handbooks.

Below is an example (or not)…

Regular slide (no tag on heading line)

There should be no "Only in the slides" after this section, in the handbooks, as it has been tagged with slidesonly.

Only in the slides

On the contrary, in the slides view, this appears, as there's a :slidesonly: tag on the current head line.

Stuff only meant for teachers

Tagging a section/slide with :teachersonly: means it isn't exported in the students handbook (nor in the slides).

Below is an example…

Regular slide (no tag on heading line)

There should be no "Only for teachers" after this section, in the slides or in the students handbook, as it has been tagged with teachersonly.

Notes only for the teachers

This slide/section contains notes, but only part of it is displayed in the presentation notes included in the handbook. Special notes and are kept only for the teachers handbook.

We use an org-mode drawer for that (additional benefit is that the content is folded by default in emacs, as it may be verbose and/or "sensitive") :

#+BEGIN_NOTES
This part of the note can be viewed by the students in the handbook.

:TEACHERSONLY:
Not this one
:END:
#+END_NOTES

Stuff only in the handbooks

Just like sections are for slides only, others can be for the handbook only, using the handbookonly tag. This may be useful for Annex sections for instance, or for stuff that the HTML exporter won't like, with inline LaTeX.

Code colorization

Code is colorized / highlighted in the slides :-)

Misc org-mode

Babel powa

As you're using org-mode, its babel components are available, to embed source code in the same lesson.org source, and manage executable code and teaching material at once.

Look for literate programing instructions in the org-mode docs to know more.

Jumping to slide number

Included is the use of the reveal.js jump plugin to allow jumping directly to slides # by entering a number and hitting RETURN. Quite handy while writing and testing slides.

Fragmented SVG display

The following SVG diagram is embedded in the HTML:

#+BEGIN_EXPORT html
  <svg
     width="210mm"
     height="297mm">
      <text
         x="50"
         y="50" class="fragment">A</text>
      <text
         x="100"
         y="50" class="fragment">B</text>
      <text
         x="150"
         y="50" class="fragment">C</text>
  </svg>
#+END_EXPORT

Its elements with the fragment class can be displayed like ordinary reveal.js fragments, as below, right here:

A B C

Missing features ?

Please try and talk to me to suggest new stuff and/or provide patches ;)

Authoring

Modify only the lesson.org

Only one file should be edited for writing the lesson's material : lesson.org

Only exception is modification of some configurations for title pages and other bits that shouldn't change much in time (see section Configuration of layout).

Use Emacs org-mode exporters or the Docker container

You have 2 options to generate the different formats:

  • either manualy use the standard org-mode exporters from inside Emacs
  • or use the Docker container for automation / reproducibility

Manual export for final documents

We're using the standard exporters so each output format will be exported from its corresponding umbrella .org source.

Open the corresponding org-mode source and export :

slides
open slides.org, then C-c C-e R ... for org-reveal export (to slides.html), provided that you have loaded org-reveal in Emacs
handbook
open handbook.org, then C-c C-e l ... for LaTeX export (to handbook.pdf)
teacher handbook
open teacher-handbook.org, then C-c C-e l ... for LaTeX export (to teacher-handbook.pdf)

Exporting slides to HTML with org-reveal

Depending on how you installed org-reveal (Git submodules or otherwise), org-reveal may already be available.

If not yet, load it with M-x load-file from the location of its Git submodule (elisp/org-reveal/ox-reveal.el by default).

Use the docker container exporter

You may use the olberger/docker-org-export docker container image I've prepared, to make org-mode exports. Or you may rebuild it yourself (see below).

Build the Docker container image

This is recommended to avoid man in the middle, IMHO:

cd docker
docker build -t obergixlocal/docker-org-export .

Run the container

Use the provided docker/docker-org-export script, which relies on the olberger/docker-org-export container image. See how Makefile does it.

Configuration of layout

Each lesson.org needs some configuration :

  • Configure org-reveal-title-slide in slides.org.
  • Configure in the headers elements like:

    • header (\lhead{...} and \rhead{...})
    • and footer (\lfoot{...} and \rfoot{...})

    ex: #+LaTeX_HEADER: \rhead{...} in handbook.org and teacher-handbook.org.

Printing slides

I've tested DeckTape using a Docker container containing PhantomJS and decktape to convert the slides to a single PDF document.

See the provided decktape.sh script that runs the container, bind-mounting the working dir into the container, so that input and output files can be found.

Note that I used a rebuilt Docker image, reusing the DeckTape Dockerfile, rebuilding with something alongside:

docker build -t obergixlocal/decktape .

Known Issues

Firefox issues ?

We have experienced issues with presentations made on some versions of Firefox, which are known by reveal.js maintainer… maybe best viewed in chrome.

You may prefer to have a PDF variant of the slides (see Printing slides) in case.

How it works / Installation

Use the source (Luke)

See the contents of the files… but be wary that it's sometimes messy and incrementally obtained.

Emacs is your buddy.

Git clone from https://gitlab.com/olberger/org-teaching.git (see the Gitlab project)

Git submodules

The repository contains Git submodules for :

  • reveal.js/
  • elisp/org-reveal
  • reveal.js's jump plugin (reveal.js-jump-plugin/)

So :

git submodule init
git submodule update

You may prefer to install them another way (ELPA repo, CDN, etc.)

Customize slides appearance

Reveal.js settings

See the org-reveal settings set in the sources and the docs for a detailed explanation.

I'm using the following for a "frugal" look close to what powerpoint or beamer (?) could look like :

#+REVEAL_HLEVEL: 2
#+REVEAL_THEME: simple
#+REVEAL_TRANS: fade
#+REVEAL_SPEED: fast
#+REVEAL_MARGIN: 0.0
#+REVEAL_EXTRA_CSS: ./presentation.css
#+REVEAL_ROOT: ./reveal.js

#+OPTIONS: reveal_center:nil 

Section separators

The highest level sections include the following properties below the heading line, to customize the look of the slide.

:PROPERTIES:
:REVEAL_EXTRA_ATTR: class="center"
:reveal_background: #dbdbed
:END:

This is intended to provide some visual sense of the transitions between sections. Please adapt and report.

Title screen picture (logos, etc.)

I'm not yet sure how much may be achieved with HTML and CSS for the title page of the slides deck, so I've relied on the embedding of a background image that will contain the logos and additional graphics.

#+REVEAL_TITLE_SLIDE_BACKGROUND: ./media/title-slide-background.png

I'm quite sure this could be improved.

Annex

Thanks

  • All contributors to org-mode (special kudos to Carsten Dominik and Bastien Guerry)
  • Yujie Wen for org-reveal
  • Hakim El Hattab for reveal.js
  • My colleagues at Telecom SudParis who had to teach with this tool without much rehersal
  • Our students who endured it for a brand new course (and included bugs)
  • Alexey Lebedeff for his docker-org-export Docker container

Feedback

I may be contacted from my Web page or via the Gitlab project.