Re: MathJax extension does not work

[chris]

On Sunday, 10 October 2021 11:14:24 CEST Rudolf Adamkovič wrote:
> I would like to use the "\mathclap" command from the "mathtools" package in 
> my Org document. In LaTeX, it works. For HTML, I visited the Org manual [1] 
> where I saw the following example:
> 
> #+HTML_MATHJAX: cancel.js noErrors.js
> 
> with a comment "it loads the two MathJax extensions ‘cancel.js’ and 
> ‘noErrors.js’ [132]." (As a side-note, the first link in [132] points to 
> 404.) Thus, I put the following into my Org file
> 
> #+HTML_MATHJAX: mathtools.js
> 

With similar scenario I ended up with:
(and `mathjax` extensions work very well)

```org-mode
#+STARTUP: latexpreview

#+BEGIN_EXPORT html
<script>
window.MathJax = {
  loader: {
    paths: {unicodeMath:
            
'https://cdn.jsdelivr.net/npm/@amermathsoc/mathjax-unicode-math@1/browser'},
    load: ['[tex]/mathtools', '[unicodeMath]/unicode-math.js']},
    tex: {packages: {'[+]': ['mathtools', 'unicode-math']}}};
</script>
#+END_EXPORT

\begin{array}{ccc}
  \underset{\longrightarrow}{\lim}^f(\alpha_1 \circ p_1)
  &\overset{\underset{\longrightarrow}{\lim}^f \phi}{\longrightarrow}&
  \underset{\longrightarrow}{\lim}^f(\alpha_2 \circ p_2)
  \\
    {}^{\mathllap{\simeq}}\downarrow
    &&
    \downarrow^{\mathrlap{\simeq}}
    \\
    \underset{\longrightarrow}{\lim}^f \alpha_1
    &\underset{f}{\longrightarrow}&
    \underset{\longrightarrow}{\lim}^f \alpha_2
\end{array}

(diagram above from: [[https://ncatlab.org/nlab/show/ind-object][ind-object in 
nLab]])

\(\Bbbc\)

This above uses the other extension, unicode-math.
```

It works when exporting to `latex` and then `pdf`,
it works very well when exporting to `html` via `org-html-export-to-html`,
it almost works with `org-latex-preview`.

Here the relevant part of my `config.org`:

```org-mode
#+begin_src emacs-lisp
  (with-eval-after-load 'org
      (add-to-list 'org-latex-packages-alist '("" "stmaryrd" t))
      (add-to-list 'org-latex-packages-alist '("" "tikz-cd" t))
      (add-to-list 'org-latex-packages-alist '("" "amscd" t))
      (add-to-list 'org-latex-packages-alist '("" "mathtools" t))
      (add-to-list 'org-latex-packages-alist '("" "unicode-math" t))
      ;; (add-to-list 'org-latex-packages-alist '("" "breqn" t))
      (add-to-list 'org-latex-packages-alist '("" "thisisastupidtestfile" t))
      (setq org-latex-create-formula-image-program 'dvisvgm)
      (setq org-format-latex-options
            (plist-put org-format-latex-options :scale 0.80)))
#+end_src
```

`thisisastupidtestfile.sty` contains a few straightforward macro of the sort of 
`\newcommand{\calT}{\mathcal{T}}`.

Everything works save `unicode-math` which doesn't work with anything `dvi`.

I use `dvisvgm` because it allows `tikz` to work with `org-latex-preview`.

Cheers,
Chris


> but it seems to do nothing; the exported HTML code not even contain the word 
> "mathtools".
> 
> A file that demonstrates the problem:
> 
> #+LATEX_HEADER: \usepackage{mathtools}
> #+HTML_MATHJAX: mathtools.js
> 
> \begin{equation*}
> \begin{aligned}
> \lim_{R\to0}F_1
> =\lim_{R\to0}\frac{2PR}{P+R}
> =\lim_{R\to0}\frac{2\cdot0\cdot{}R}{0+R}
> =\lim_{R\to0}\frac{0}{R},
> =\underbrace{\lim_{R\to0}\frac{0}{1}}_{\mathclap{\text{by L'Hôpital's Rule 
> with $\frac{d}{dR}R=1$}}}
> =\lim_{R\to0}0
> =0.
> \end{aligned}
> \end{equation*}
> 
> Rudy
> 
> [1] https://orgmode.org/manual/Math-formatting-in-HTML-export.html
> 
>