[Tour 05] Math and Copying as LaTeX

Formulas render as SVG at 1.15 times the size of the text around them, in New Computer Modern Math. A comma or full stop after an inline formula stays on its line. Select text around a formula and copy, and the formula comes out as LaTeX: $...$ inline, $$...$$ display. Double-click a formula to select just that one.

01Try it#

Select this paragraph and the formula under it, copy, and paste somewhere. This sum converts: $\sum_{i=1}^n x_i^2$ . So do this fraction, $\frac{a + b}{2}$ , and this labelled arrow, $a \xrightarrow{\text{f}} b$ . This one is not convertible: $\text{[unsupported formula]}$ , and neither is this boxed one: $\text{[unsupported formula]}$ . Written with mi instead, the first converts after all, exactly as typed: $\text{[unsupported formula]}$ . The display formula converts too, its two rows in an aligned block:

\begin{aligned} (a + b)^2 &= a^2 + 2 a b + b^2 \\ &\geq 4 a b \end{aligned}

The convertible formulas paste as LaTeX; the two that are not paste as \text{[unsupported formula]}, and a tip at the foot of the window names what stopped them: font style and box.

02Writing math#

Write Typst’s own math between dollar signs, or LaTeX with mi (inline) and mitex (display) from utils/mitex.typ. Both render the same:

typst

#import "/utils/mitex.typ": mi, mitex

Typst $e^(i pi) + 1 = 0$ and LaTeX #mi(`e^{i\pi} + 1 = 0`).

#mitex(`\int_0^\infty e^{-x^2} \, dx = \frac{\sqrt{\pi}}{2}`)

Renders as

Typst $e^{i \pi} + 1 = 0$ and LaTeX $e^{i \pi} + 1 = 0$ .

\int_0^{\infty} e^{- x^2} \, d x = \frac{\sqrt{\pi}}{2}

03Copying as LaTeX#

A formula written with mi or mitex copies as the LaTeX you wrote, exactly. Typst’s own math has lost its source text by the time the page is built, so the theme rebuilds LaTeX from the parsed formula: the same maths, with its own spacing and braces.

Table 1

Typst	Renders	Copies as
$sum_(i=1)^n x_i^2$	$\sum_{i=1}^n x_i^2$	`\sum_{i=1}^n x_i^2`
$f(x) = cases(x^2 "if" x > 0, 0 "otherwise")$	$f(x) = \begin{cases} x^2 \text{ if } x > 0 \\ 0 \text{ otherwise} \end{cases}$	`f(x) = \begin{cases} x^2 \text{ if } x > 0 \\ 0 \text{ otherwise} \end{cases}`
$(a + b)/2 + sqrt(x) + root(3, y)$	$\frac{a + b}{2} + \sqrt{x} + \sqrt[3]{y}$	`\frac{a + b}{2} + \sqrt{x} + \sqrt[3]{y}`
$bold(v) + bb(R)^n + cal(L)$	$\boldsymbol{v} + \mathbb{R}^n + \mathcal{L}$	`\boldsymbol{v} + \mathbb{R}^n + \mathcal{L}`
$lim_(x -> 0) (sin x)/x = 1$	$\lim_{x \to 0} \frac{\sin x}{x} = 1$	`\lim_{x \to 0} \frac{\sin x}{x} = 1`
$mat(1, 2; 3, 4) vec(x, y)$	$\begin{pmatrix} 1 & 2 \\ 3 & 4 \end{pmatrix} \begin{pmatrix} x \\ y \end{pmatrix}$	`\begin{pmatrix} 1 & 2 \\ 3 & 4 \end{pmatrix} \begin{pmatrix} x \\ y \end{pmatrix}`
$integral_0^1 f(x) dif x$	$\int_0^1 f(x) \,\mathrm{d} x$	`\int_0^1 f(x) \,\mathrm{d} x`
$a stretch(->)^"f" b$	$a \xrightarrow{\text{f}} b$	`a \xrightarrow{\text{f}} b`
$hat(x) + overline(z) + abs(x) + norm(v)$	$\hat{x} + \overline{z} + \|x\| + \\|v\\|$	`\hat{x} + \overline{z} + \|x\| + \\|v\\|`

The converter covers scripts and primes, fractions, roots, binomials, brackets (with \left / \right around tall content), matrices and vectors, cases, rows and alignment (in aligned / gathered), accents, over- and underbraces, labelled arrows (\xrightarrow), operators such as \sin and \lim, font styles (\mathbf, \mathbb, \mathcal, …), spacing, and about 430 symbols taken from MiTeX’s command table. Quoted text copies as \text{...}, escaped for LaTeX.

04What cannot be converted#

Some formulas have parts LaTeX has no counterpart for. Rather than copy LaTeX that is wrong or will not compile, the whole formula copies as \text{[unsupported formula]}, and a tip at the foot of the window names the parts.

Table 2

Typst	Renders	Stopped by
$bold(cal(A))$	$\text{[unsupported formula]}$	`font style`
$mat(1, 2; 3, 4; augment: #1)$	$\text{[unsupported formula]}$	`augment`
`$x + #box(stroke: .5pt, inset: 2pt)[$y$]$`	$\text{[unsupported formula]}$	`box`
$a ⧺ b$	$\text{[unsupported formula]}$	`⧺`

Font style: two styles stacked, such as bold calligraphic, match none of the single LaTeX styles the converter tells apart.
augment: a matrix’s dividing line, which LaTeX’s matrix environments do not draw.
box: an element with no LaTeX counterpart the converter knows.
⧺: a symbol missing from the table; LaTeX has no standard command for it.

While tola dev runs, the terminal lists every such formula after each rebuild, pointing at its line in the source like a compiler warning, so it can be rewritten before anyone copies it. A page that shows such formulas on purpose, as this one does, opts out with a line // math-check: ignore in its source.

When a formula has to copy cleanly, write it in LaTeX with mi. These two render the same as the first and third rows and copy as written:

typst

#mi(`\boldsymbol{\mathcal{A}}`) and #mi(`x + \boxed{y}`)

Renders as

\text{[unsupported formula]}

and

\text{[unsupported formula]}

05Design choices#

A copied formula usually lands in Markdown, notes or a chat, where KaTeX or MathJax draws it (GitHub, Obsidian and Typora use MathJax). Where LaTeX has more than one spelling, the theme writes the one both read as they come, with no extra packages or settings; pasting into a full LaTeX document comes second.

Table 3

Choice	Trade-off
Equivalent LaTeX, rebuilt from the formula	The same maths, not the text you typed. Write `mi` / `mitex` to copy your own text.
A whole formula or a placeholder	A formula with one part LaTeX lacks copies as `\text{[unsupported formula]}`, never as LaTeX that is wrong.
Symbols one of the two lacks, as the character itself	`≔`, `⟦` and `∯` paste as Unicode, which both draw; pdfLaTeX rejects them.
Special characters in quoted text, outside `\text{}`	`"snake_case"` copies as `\text{snake}\_\text{case}`, since MathJax shows escapes inside `\text{}` as typed. `~` and `^` become `\sim` and `\hat{}`, which look close.
Labelled `⇒`, `⇔` and `↪` with `\overset` / `\underset`	MathJax lacks their stretching commands, so the arrow keeps its length under a long label. `→`, `←` and `↦` stretch (`\xrightarrow`).
Spacing as the nearest command	`space.thin` and its kind become `\,`, `\:`, `\;` or `\quad`; the rest `\hspace` or `\phantom`.

Colour and the numbers of numbered equations are not copied. In a full LaTeX document, some commands need amsmath, amssymb, mathtools, cancel or mathrsfs.