Keybinding to toggle incremental (fragment) reveal at runtime, for Q&A after a talk

[brry]

Description

During a talk, having bullets appear one at a time (incremental: true)
keeps the audience reading along with me instead of ahead. But once the
talk ends and Q&A starts, that same behavior gets in the way: I want to
jump between slides with a single arrow-key press, not click through
every bullet again. Re-rendering with incremental: false isn't an
option in the middle of a presentation.

reveal.js already has everything needed for this: a runtime option,
Reveal.configure({fragments: true/false}), that does exactly this.
It's just not exposed via any keybinding or UI control.

MWE (two slides, self-contained .qmd, renders to a single HTML file):

---
title: "Toggle incremental reveal at runtime"
format:
  revealjs:
    incremental: true
    embed-resources: true
---

## Normal presentations should reveal bullet points incrementally

- so that viewers read what I talk about, not ahead
- after the talk, during Q&A, incremental reveal gets in the way
- press "a" (no Shift) to toggle incremental reveal on/off

## Toggling that on/off would be a nice feature

- re-rendering with `incremental: false` isn't an option mid-presentation
- you can toggle `Reveal.configure({fragments: ...})` at runtime
- would be nice to have as a built-in keybinding/UI control

<script>
// An inline <script> here lands in the HTML body *before* reveal.js itself
// is loaded and initialized, so `Reveal` is undefined at this point and
// `Reveal.addKeyBinding(...)` throws silently (see browser console).
// Deferring until the DOM/Reveal is ready works around that:
document.addEventListener('DOMContentLoaded', function() {
  function addToggle() {
    Reveal.addKeyBinding(
      {keyCode: 65, key: 'a', description: 'Toggle fragment animations'},
      function() {
        Reveal.configure({fragments: !Reveal.getConfig().fragments});
        Reveal.sync();
      }
    );
  }
  if (window.Reveal && Reveal.isReady()) {
    addToggle();
  } else {
    Reveal.on('ready', addToggle);
  }
});
</script>

Press "a" (no Shift) to toggle. Pressing it again on either slide flips
fragment-by-fragment reveal on/off for the rest of the deck.

Would it make sense to have Quarto's revealjs format expose this as a
built-in keybinding (or at least document the pattern), similar to how
s already toggles the speaker view?

PS: uploading qmd files would be a nice option here :)

[mcanouil]

First, I would suggest for you to build a Quarto extension with the reveal.js plugin snippet you have.
Then based on traction this post and your possible plugin/Quarto extension, it would be possible to considerate making this native.

For instance, in four years, you are the first raising this as an issue.

In addition, to see if there is a broader audience for this, it will allows you to maturate your snippet based on edge cases you did not think about yet, while not putting all that burden onto the Quarto team which has a limited amount of time.

There are at least 52 Quarto extensions that deliver a Reveal.js plugin to fill some gaps in Quarto.
Take my Reveal.js Tabset plugin, it's been around for a year and got quite a lot of updates for various edge cases, I'm even working on it right now for other cases in which it does not work well in Quarto (or even native Reveal.js).
At the same time, it also helps me have tabset that I can navigate with keyboard.

[brry]

Nice, I was not aware anyone can just create plugins in a github repo. I'll see if this discusion gets some traction before doing the work - totally fair enough on your end and thanks for the pointers!!!