breather

Give tall inline math room to breathe. One show rule fixes lines that
overlap because of display-style fractions, matrices, big operators,
nested roots — while leaving the spacing of ordinary lines untouched.

The problem

Typst computes line spacing from the font's cap-height and baseline
text edges, not from the actual ink. Inline math that extends past those
edges — a math.display fraction, a matrix — collides with the
neighbouring lines:

The usual workarounds both hurt: raising par(leading) wastes space on
every line, and setting top-edge: "bounds" on all equations makes
ordinary lines uneven (a mere descender in $y_p$ pushes lines apart).

The fix

breathe measures every inline equation and switches it to bounds-based
edges only when it is actually tall. Tall lines expand exactly as
needed; every other line keeps perfectly regular leading.

#import "@preview/breather:0.1.0": breathe
#show: breathe

That's it — active for the whole document. It also works in justified
paragraphs where tall math wraps naturally:

Options

#show: breathe.with(threshold: 1.1em, only: none, enabled: true)

Option	Default	Description
threshold	1.1em	Equations with ink taller than this get corrected spacing. Em values resolve against the text size at the equation.
only	none	Restrict the check to equations containing given elements: only: math.frac, only: ("frac", "mat"). none checks every inline equation.
enabled	true	Initial state — handy as a template flag: breathe.with(enabled: flag).

Toggling mid-document

breathe-on and breathe-off flip the rule anywhere after #show: breathe:

#import "@preview/breather:0.1.0": breathe, breathe-on, breathe-off
#show: breathe

#breathe-off()                             // Typst default behaviour again
#breathe-on(threshold: 1.4em)              // back on, higher bar
#breathe-on(only: math.frac)               // only equations with fractions
#breathe-on(only: none)                    // back to checking everything

Notes

• The / fraction shorthand desugars to math.frac, so only: math.frac
  catches $1/2$ too.
• Spacing between the expanded line and its neighbours is still governed
  by par(leading) — breather only makes the line's true height known.
• Works inside grids, columns and list/task layouts (e.g. the
  taskize package): it fixes
  the \-separated lines within a cell, and it also stops cells with
  tall math from bleeding across the row gutter — gutter values are never
  changed, they just become the real visual gap.
• Overhead is one extra measurement per inline equation: a stress test
  with 3000 equations compiles about 25% slower; a typical worksheet
  (~200 equations) pays around 15 ms.
• This works around typst#1028;
  if Typst gains native ink-aware line spacing, you can simply delete the
  two lines.

Changelog

[0.1.0] - 2026-07-13

Added

• breathe: document-wide show rule that measures every inline equation
  (with bounds text edges, since plain measurement under-reports the ink
  height of matrices and similar) and expands only lines whose math is
  taller than threshold.
• only filter to restrict the check to equations containing given
  elements (math.frac, "mat", …).
• enabled flag for template integration.
• breathe-on / breathe-off to toggle or retune the rule mid-document.

License

MIT