self-contained-math:true in reveal.js format still require internet access

[AndreiBiziuk]

Bug description

When creating presentations with formulas in the reveal.js format, the formulas do not render without Internet access, even if you specify self-contained-math: true.

The presentation file always requests the address https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.0/MathJax.js?config=TeX-AMS_HTML-full and without Internet access the formulas are not rendered.

Steps to reproduce

1. Create new default project
2. Modify _quarto.yml

project:
  title: "Test"

format:
  revealjs: 
    embed-resources: true
    self-contained-math: true 

3. Create index.qmd

---
title: "Test"
---

## Math

$$x^2$$

4. Render project quarto render
5. Open index.html
6. See request to Internet in developer console (F12)
7. Or disconnect from Internet and see not rendered math on slide

Expected behavior

Math rendered offline

Actual behavior

Math do not render offline

Your environment

OS: Arch Linux
IDE: VsCode

Quarto check output

Quarto 1.5.29
[✓] Checking versions of quarto binary dependencies...
      Pandoc version 3.1.11: OK
      Dart Sass version 1.70.0: OK
      Deno version 1.41.0: OK
      Typst version 0.11.0: OK
[✓] Checking versions of quarto dependencies......OK
[✓] Checking Quarto installation......OK
      Version: 1.5.29
      Path: /opt/quarto/bin

[✓] Checking tools....................OK
      Chromium: 869685
      TinyTeX: (not installed)

[✓] Checking LaTeX....................OK
      Using: Installation From Path
      Path: /usr/bin
      Version: undefined

[✓] Checking basic markdown render....OK

[✓] Checking Python 3 installation....OK
      Version: 3.11.8
      Path: /usr/bin/python3
      Jupyter: 5.7.2
      Kernels: haskell, python3

[✓] Checking Jupyter engine render....OK

[✓] Checking R installation...........OK
      Version: 4.3.3
      Path: /usr/lib64/R
      LibPaths:
        - /home/andrei/R/x86_64-pc-linux-gnu-library/4.3
        - /usr/lib/R/library
      knitr: 1.45
      rmarkdown: 2.25

[✓] Checking Knitr engine render......OK

[mcanouil]

Double dollars should be on their own line.
Use single dollar for inline Maths.

I cannot reproduce using a single document project or using _quarto.yml:

Quarto document	HTML
--- title: "Quarto Playground" format: revealjs: embed-resources: true self-contained-math: true --- ## Math This is inline math: $x^2$ This is display math: $$ x^2 $$

[AndreiBiziuk]

---
title: "Quarto Playground"
format:
  revealjs: 
    embed-resources: true
    self-contained-math: true 
---

## Math

This is inline math: $x^2$

This is display math:

$$
x^2
$$

With internet:

Without internet:

[AndreiBiziuk]

Link in the source code of page:

[mcanouil]

What I shared was rendered following the steps below:

1. turning off network connection
2. rendering with Quarto (in a clean workspace, without any previous rendering)

[AndreiBiziuk]

I tried to build the project with the Internet turned off and in a clean directory, nothing changed.

When you opened a presentation offline, did you clear your browser cache?

[AndreiBiziuk]

It looks like the MathJax plugin is embedded in the assembled presentation, but the plugin itself turns to the Internet for resources.

[mcanouil]

Ok, I can reproduce.
Now, is it Quarto or Pandoc that is doing this wrong.

Edit: Quarto takes over that part which works correctly in the case of format: html but not for format: revealjs.
self-contained-math is only listed for html format and not for revealjs, which explains why it does nothing.
At the same time the codebase involves the two format:

• quarto-cli/src/command/render/template.ts

  Lines 178 to 184 in 7edfb45

  	if (isHtmlDocOutput(format.pandoc) || isRevealjsOutput(format.pandoc)) {
  	if (
  	((flags && flags[kSelfContained]) || format.pandoc[kSelfContained] ||
  	(flags && flags[kEmbedResources]) || format.pandoc[kEmbedResources]) &&
  	!format.render[kSelfContainedMath]
  	) {
  	const math = mathConfig(format, flags);

  
  (Cannot investigate this more right now)

[blendersamsonov]

I'm experiencing the same bug. Would love some attention being drawn to the problem

[cderv]

It looks like the MathJax plugin is embedded in the assembled presentation, but the plugin itself turns to the Internet for resources.

This is what happens. Math in Revealjs is supported through the Math Plugins, which expect the mathjax configuration. The JS library is not loaded in a HTML script tag from the HTML itself, like with HTML format.

So the embed logic from Pandoc to make everything inlined is not working here.

As documented in the Revealjs doc (https://revealjs.com/math/), to make it work offline, it would require downloading Mathjax and configuring revealjs to use the local version - but this also means it won't be embed inside a single HTML.

I don't know if there is a good solution here 🤔 Maybe using KaTeX and server side rendering would be the easiest way to provide self contained math in Revealjs.

Pandoc itself is not embedding mathjax JS when doing pandoc --to revealjs -s --mathjax --embed-resources. This is a limitation of Mathjax and self contained feature.

[AndreiBiziuk]

It is not necessary for the presentation to be a single file. The main thing is that it can be launched offline with the ability to draw formulas.

[cderv]

I see. This is is not possible with Mathjax right now. I'll see if other math framework like KaTeX can allow this. Thanks for the feedback