In a custom crossref, is it possible to set latex math font size (for equations)

[zeigerpuppy]

Description

I am trying to increase the math font size in a custom quarto crossref environment.

Rendering to PDF, I have included an custom environment, to create floats for equations:

crossref:
  custom:
    - kind: float
      reference-prefix: Equation
      key: eqn
      latex-env: eqn

equations can then be added in the qmd file and they are properly floated, for example:

::: {#eqn-schrodinger}
$$
i \hbar \frac{d}{d t}|\Psi(t)\rangle=\hat{H}|\Psi(t)\rangle
$$ 

Time-dependent Schrödinger equation, $\hbar$=reduced Planck constant, $t$=time, $|\Psi(t)\rangle$=state vector, $\hat{H}$=Hamiltonian operator
:::

in the .tex file produced, this is correctly added to the environment:

\begin{eqn}

\centering{

\[
i \hbar \frac{d}{d t}|\Psi(t)\rangle=\hat{H}|\Psi(t)\rangle
\]

}

\caption{\label{eqn-schrodinger}Time-dependent Schrödinger equation,
\(\hbar\)=reduced Planck constant, \(t\)=time, \(|\Psi(t)\rangle\)=state
vector, \(\hat{H}\)=Hamiltonian operator}

\end{eqn}%

However, I would like to increase the size of the math environment text for all equations.

I have tried some changes in the latex template and header.tex, but none have worked.

Tried:

1. DeclareMathSizes in preamble (LaTeX template): \DeclareMathSizes{10}{30}{16}{12} but it does not change text size
2. AddToHook in header.tex: \AddToHook{env/eqn/begin}{\LARGE}
3. modifying environment in header.tex:

\usepackage{environ}
\NewEnviron{eqn}{%
    \begin{equation}
    \scalebox{1.5}{$\BODY$}
    \end{equation}
    }

None of these changes have increased the math font in the eqn environment.

Is there a way to modify the equation size using a custom crossref environment?

[mcanouil]

Have you tried searching in more specialised platforms where this specific LaTeX might have already been answered?

(Your question is a LaTeX question rather than a Quarto question.)

[zeigerpuppy]

Yes, I did try a number of options from general LaTeX forums.

While, I agree that this is primarily a LaTeX issue, the way in which Quarto implements the custom cross-ref environments does make this a bit tricky (and I think relevant).

When the custom crossref is added (as above)... quarto inserts the following after anything which is added in header.tex

\@ifpackageloaded{float}{}{\usepackage{float}}
\floatstyle{plain}
\@ifundefined{c@chapter}{\newfloat{eqn}{h}{loeqn}}{\newfloat{eqn}{h}{loeqn}[chapter]}
\floatname{eqn}{Equation}
\newcommand*\listofeqns{\listof{eqn}{List of Equations}}

Therefore, customisations to that environment made in the LaTeX template will generally be overridden by the quarto-defined environment.

I guess the more quarto-specific question, is how would we customise that environment (as I don't know of a template mechanism that will allow further environment customisation to be set before /begin{document}.

I guess, ideally it would be good for crossref to allow a hook to have some customisation of the environments created.

[zeigerpuppy]

p.s. I will try modifications in before-body.tex (although that is added after /begin{document})

[zeigerpuppy]

After a bit more digging, a workaround for this is to use the Theorem environment. That has a much better default math font size (using amsthm).

I do think it would be great to have the option of modifying some characteristics of custom crossref environments, but great to see there is an existing environment which meets most of the use-case.

[mcanouil]

You can make a more formal feature request at https://github.com/orgs/quarto-dev/discussions/categories/feature-requests

Note that because Quarto is multi format, new features tends to require to work across most if not all formats.