7.7 Presenter Notes

Q: Why using presenter notes?

A: A common mistake in presentations, especially for presenters without much experience, is to stuff a slide with too much content. The consequence is either a speaker, out of breath, reading the so many words out loud, or the audience starting to read the slides quietly by themselves without listening. Slides are not papers or books, so you should try to be brief in the visual content of slides but verbose in verbal narratives. If you have a lot to say about a slide, but cannot remember everything, you may consider using presenter notes.

---

Q: How to add presenter notes in xaringan?

A: In xaringan, presenter notes are written with ???.

Everything after ??? (on the same slide) will not appear on the slide, but will show up in presenter mode when you press p to toggle presenter view.

---

The holy passion of Friendship is of so sweet and steady
and loyal and enduring a nature that it will last through
a whole lifetime...

???
This is notes for presenter only.

• Blank line under ??? is NOT required.

---

Q: What is the behavior of presenter mode?
A: The presenter mode shows thumbnails of the current slide and the next slide on the left, presenter notes on the right (see Section 7.3.5), and also a timer on the top right.

The keys c (clone) and p (presenter mode) can be very useful when you present with your own computer connected to a second screen (such as a projector).

1. Press c to clone the slides to a second screen (e.g., projector).

2. On your own computer, press p to toggle presenter mode.

3. When you present, you can see the presenter notes and the time on your own computer, while the audience sees only the slides on the projector.

   When you nevigate across slides on your own computer, the two screens are synchronized, so the audience sees the same slide as you do.

Only you can see the presenter mode, which means only you can see presenter notes and the time, and preview the next slide. You may press t to restart the timer at any time.

⚠️ One thing to check: if you mirror your display instead of extending it, then the audience will see exactly what you see (including notes). To avoid this, make sure you use extended display mode so only you get the presenter view.

The figure below shows the Displays settings on macOS for extended display mode.

• Do not check the box “Mirror Displays”.
• Instead, separate the two displays, so you can drag the window with the normal view of slides to the second screen.

7.7.1 Print to PDF with presenter notes

Need two files:

• theme/print-notes.css: CSS file to style the print layout, which is used by print-notes.R to generate the PDF with notes.
• print-notes.R: R script to render the slides and print to PDF with notes.

One command, works for any xaringan deck in the repo:

# assume both print-notes.R and your .Rmd are in Slides/
cd Slides
./print-notes.R <deck>.Rmd

That writes <deck>_notes.pdf next to the deck. E.g., ./print-notes.R equity_valuation.Rmd → equity_valuation_notes.pdf.

It also runs fine from the repo root, which is handy if you’re not in Slides/:

Rscript Slides/print-notes.R Slides/equity_valuation.Rmd

• Rscript is the a command-line program to run R scripts.

Flags (all optional):

Flag	Effect
--render	Re-knit the .Rmd first. Without it, the existing .html is printed as-is (fast).
-o FILE	Choose the output path instead of <deck>_notes.pdf.
--zoom 0.5	Shrink the slide on the page to make room for long notes (default 0.58).
--wait 15	Extra seconds for MathJax to finish on heavy decks (default 10).

Typical workflow after editing a deck:

• Approach 1: Render first, then print to PDF with notes. This is the most common workflow. ✅

  # Render first, this creates <deck>.html and <deck>.pdf
  renderthis::to_pdf('<deck>.Rmd')
  
  # Print PDF with notes. This creates <deck>_notes.pdf.
  # without --render, the existing <deck>.html will be used 
  # to print to PDF with notes; fast
  ./print-notes.R <deck>.Rmd

• Approach 2: Use --render to render and print in one command.

  # render and print; creates <deck>_notes.pdf directly from the latest <deck>.Rmd
  ./print-notes.R <deck>.Rmd --render

--render makes sure the R chunks are re-run and the .html is up-to-date before printing to PDF. Otherwise, you may get a PDF with stale content.

If no <deck>.html exists, --render is implied. A render will be conducted before printing to PDF.

Three things to keep in mind:

• Notes come from ??? blocks. Everything between ??? and the next --- in the .Rmd becomes that slide’s notes. A deck with no ??? still prints — you just get portrait pages with a slide and no notes box (I tested mkt_efficiency.Rmd, which has zero notes: 55 pages, slides only). For a slides-only PDF keep using your normal landscape print.
• theme/print-notes.css must stay next to the script, since the script looks for it at <script dir>/theme/print-notes.css. Edit that file to change fonts, the “Presenter notes” label, or the slide border permanently.
• Console noise is normal. Some decks log JS warnings during printing (mkt_efficiency.Rmd prints a \$ is not defined from kePrint.js); the PDF is still produced. Only trust the final ✓ <path> line.

Ref:

• R Markdown: The Definitive Guide, Section 7.3.5