folarrow

A LaTeX package providing arrows with three slanted shaft strokes to denote foliated-bundle projections, for amscd, xy-pic, tikz-cd and inline math.

Version 20261010.0, 2026-10-10. Author: Yuwsuke Kieda

A Japanese README is in README-ja.md.

Description

In a fiber-bundle diagram V -> E -> M, the projection E -> M is usually a vertical or horizontal arrow. Three slanted strokes across its shaft can indicate a foliated bundle. This package provides such arrows:

Diagram-package arrows are unchanged; strokes are overlaid using pict2e (or PGF for tikz-cd). Their length, spacing and thickness follow the current math font's arrowhead and shaft in every math style.

The four inline arrows (\folrightarrow etc.) use single glyphs with the strokes:

• Type 1 fonts for Computer Modern, Latin Modern, newtx, txfonts, newpx and pxfonts;
• OpenType fonts for 49 OpenType math fonts used with unicode-math (LuaLaTeX, XeLaTeX).

These glyphs copy from PDFs as U+2192, U+2190, U+2193 and U+2191. Other math fonts use drawn strokes.

Arrows follow bold math (\boldmath, \bm): inline arrows use fonts made from the bold symbol fonts, and drawn strokes follow bold arrows. With unicode-math, set the bold math font using \setmathfont{...}[version=bold].

The shape of the strokes can be changed with \folarrowsetup{span=, lean=, gap=, shift=, thickness=} or the same package options.

Light version: the lite option

\usepackage[lite]{folarrow}

With lite, all arrows are drawn and no Lua module, measured data or arrow fonts are needed. Use it to avoid embedding arrow fonts in PDFs. Default behaviour is unchanged.

Requirements

• LaTeX 2022-06-01 or later, pict2e, graphics; PGF/TikZ for tikz-cd.
• Tested with pdfLaTeX, LuaLaTeX, XeLaTeX and upLaTeX+dvipdfmx (TeX Live 2025 and 2026). For dvipdfmx, pass the dvipdfmx option to the document class.
• No special fonts are required; the arrow fonts are included.
• In TeX Live 2025 and 2026, xy-pic itself fails with LuaLaTeX (unrelated to this package).

Documentation

The manuals are in English and Japanese, with the same contents.

• doc/folarrow-en.pdf, doc/folarrow-ja.pdf: the full manual, with verification tables.
• doc/folarrow-lite-en.pdf, doc/folarrow-lite-ja.pdf: lite manual; each example is a compilable, complete document.

Installation

Install the files in a TEXMF tree as follows:

pdfLaTeX, LuaLaTeX, dvipdfmx and xdvipdfmx load folarrow.map automatically. For dvips, enable it with updmap (in TeX Live: updmap-user --enable Map=folarrow.map).

Files

• tex/: folarrow.sty (the package), folarrow.lua (LuaTeX module), folarrow-fonts.def (measured data of Type 1 math fonts), folarrow-glyphs.def, folarrow-otf.def (tables of the arrow fonts).
• fonts/: the arrow fonts (Type 1, TFM, OpenType) and the map file.
• doc/: the manuals (PDF and source) and the examples.
• source/: Python scripts for generating arrow fonts (see below).
• LICENSE: the MIT License of the package.
• licenses/: license texts of the arrow fonts, and FONTS.md, the list of the arrow fonts with their original fonts, original copyright notices and licenses.

Sources of the arrow fonts

The arrow fonts are generated from the original math fonts by two Python scripts:

• source/mkfolfonts.py: the Type 1 fonts, their TFM files, folarrow.map and folarrow-glyphs.def;
• source/mkfolotf.py: the OpenType fonts and folarrow-otf.def.

The scripts add three strokes to arrow outlines from the original TeX Live fonts. They require Python 3 with fontTools and skia-pathops, plus TeX Live's kpsewhich, tftopl, vftovp, pltotf and t1asm. Output goes to the TDS tree specified by FOLARROW_ROOT, which must contain tex/latex/folarrow/folarrow-fonts.def; otherwise, the scripts stop without writing. For example, arrange the files of the package in a directory as in the table of the Installation section (a TDS tree) and run

FOLARROW_ROOT=/path/to/the/tree python3 source/mkfolfonts.py
FOLARROW_ROOT=/path/to/the/tree python3 source/mkfolotf.py

mkfolotf.py imports mkfolfonts.py, so keep both scripts together. Package users need not run them.

License

• folarrow.sty, folarrow.lua, the .def files, the documentation and the scripts in source/: MIT License (LICENSE).
• Arrow fonts in fonts/ retain their source licenses: SIL Open Font License 1.1, GUST Font License, or GNU GPL with font exception. See licenses/FONTS.md. Derived font names do not use the originals' Reserved Font Names.