mapotofu

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mapotofu is a build program for CJK composite fonts: it merges a CJK font with a Latin font, and optionally CJK italic sources (a regular-script or slanted font drawn as such), into hinted variable and static fonts, from one TOML file per font project.

Table of Contents

• Overview
• Features
• Prerequisites
• Installation
• Usage
• Font Project Layout
• Configuration
• Output Files
• Testing
• Compatibility
• Disclaimer
• License
• Author

Overview

A font project is a directory holding a mapotofu.toml. mapotofu reads it, downloads the source fonts the project lists, builds every font of every family, region and style in two steps, and packs the result into zip files for a release:

1. Fonts: each font is assembled from the sources as an unhinted CFF2 variable font, with the metadata a web package will need.
2. Desktop: the variable fonts are hinted with otfautohint, the static weights are instanced from them, and both are packaged as standalone OTF files and OTC collections.

The CJK part comes from the variable region fonts of Source Han Sans; the Latin part and, when the project gives any, the ideographs and kana of the italics come from the fonts the project names.

Features

• Variable and static: CFF2 variable-weight fonts, and static CFF instances of the named weights.
• Families: any of Gothic, UI and Mono.
  • Gothic: curly quotes, the middle dot, the ellipsis and the em dash are full width, in the forms of the region.
  • UI: curly quotes keep their proportional width, as in Latin text.
  • Mono: fixed pitch, Latin and punctuation in half-width cells (a Latin source's scale makes it fit).
• Regions: any of SC, TC and J, each with its own glyph forms, language system and local names.
• Extensions: ideographs outside each region's common list go into separate extension fonts, so the main fonts stay small.
• Italics: Latin italics with the upright CJK glyphs, or, for the regions listed in [fonts.italic_cjk], with those of the CJK italic sources; the variable italics switch between their weights along the weight axis (rvrn), and each static italic takes the nearest one. A source whose em box differs (such as a narrow font) can be scaled (scale_x, scale_y) and centred in the full width (advance).
• Hint cache: hints are kept per glyph in the project's hints/, so each glyph is hinted once and later builds take its hints from there.
• Incremental: work is redone only where what it is made from changed (sources, configuration, code, library versions); an interrupted or failed run is resumed by running it again.
• Collections: fonts of one pool share their glyph tables, which an OTC stores once.
• Tools: mapo tool measures, compares, draws and converts fonts (stroke widths and glyph size, how a family changes with weight, the glyphs that change between two weights unlike their kind, whether two fonts have exactly the same glyphs, the same characters in several fonts side by side, every glyph of a font at several weights, the points of an outline, sample lines, TrueType outlines to OTF); the modules behind them can be imported as a Python library.

Prerequisites

• Python ≥3.12
• uv
• Dependencies, installed with mapotofu: afdko ≥5.0.1 (otfautohint and tx), fontTools ≥4.68.0, cffsubr ≥0.4.0, uharfbuzz ≥0.57.0, brotli ≥1.2.1; for the tools, freetype-py ≥2.5.1, NumPy ≥2.5.4, Pillow ≥13.0.0, scikit-image ≥0.26.0, SciPy ≥1.18.1
• Memory: subroutinizing a static font takes about 100 times its size. mapotofu records what each job took in build/memory.json and starts a job only when that much memory is free.

Installation

As a Dependency of the Font Project (Recommended)

1. In the font project (a uv project with a pyproject.toml), add mapotofu:

   uv add mapotofu
   

2. Run it from the project:

   uv run mapo all
   

Note: a font project that wants the same fonts from the same tag should pin mapotofu to a version, e.g. uv add "mapotofu==<version>".

As a Tool

uvx --from mapotofu mapo all

Building from Source

git clone https://github.com/lutianyu2001/mapotofu.git
cd mapotofu
uv sync

A font project can then take it by path in its pyproject.toml:

[tool.uv.sources]
mapotofu = { path = "../mapotofu", editable = true }

Usage

Run in a font project, i.e. the directory holding mapotofu.toml or one below it. MAPOTOFU_ROOT names the project when run from elsewhere. -h, --version and --man work in any directory. mapo and mapotofu are the same command.

mapo [-h] [-j N] [--only [KEY ...]] [--man] [--version] STEP

• -j, --jobs (default: 4)
  • Parallel processes; for desktop, the pools hinted at once, each over cores/N runs
• --only
  • For fonts, desktop and all: only the pools of these fonts, such as Gothic-SC-Upright, or these pools, such as Italic-SC
• --man
  • Show the manual (see Manual)
• --version
  • Print the version

Recommended order for a new project:

1. Download the sources:

   uv run mapo fetch
   

2. Build everything:

   uv run mapo all
   

3. Pack the release:

   uv run mapo release
   

If a run stops (out of memory, interrupted), run the same command again: finished work is kept.

Tools

mapo tool NAME runs one of the tools that come with mapotofu. They take font files and need no font project, so they run in any directory; mapo tool lists them and mapo tool NAME -h shows the arguments of one.

A FONT is a file, a face of a collection (Font.ttc#2) or a place on the axes of a variable font (Font[wght].ttf@wght=500).

Example:

mapo tool stems <FONT_A> "<FONT_B>@wght=400"
mapo tool sheet <OUT.png> "永国あA" <FONT_A> "<FONT_B>@wght=400"

The tools are modules of the package mapotofu.tools, and their functions can be imported, as can the two modules they are made of: mapotofu.tools.raster (fonts opened by such a spec, their glyphs rasterised) and mapotofu.tools.skeleton (the skeleton of a glyph as a graph, with the width of its strokes and strokes traced through junctions).

from mapotofu.tools.raster import FontSource
from mapotofu.tools.stems import font_stems

print(font_stems(FontSource("<FONT>")))

Manual

man mapo (or man mapotofu) is the whole manual, in English and in Chinese: the steps and options, and every key of mapotofu.toml and sources.toml, with a complete example. mapotofu installs it into its environment, so man finds it wherever that environment's bin is on PATH, as under uv run:

uv run man mapo

mapo --man shows the same page from anywhere: in the pager, in the language of the locale.

Font Project Layout

sources.toml lists zip archives, with the members to take, and single files:

[[archive]]
url = "<URL of a zip file>"
sha256 = "<SHA-256 of the file>"
members = { "<path inside the zip>" = "<name under sources/>" }

[[file]]
url = "<URL of a font file>"
sha256 = "<SHA-256 of the file>"

Configuration

mapotofu.toml has four tables. Which one a change is in decides how much is built again:

The manual explains every key and has a complete example (see Manual); tests/project/mapotofu.toml is a full configuration with comments.

Output Files

Note: fonts made from other fonts are Modified Versions of them. With sources under the SIL Open Font License, the result must be released under it too, and its names must not use the sources' Reserved Font Names (Source Han Sans reserves "Source").

Testing

uv run pytest

The tests run on tests/project, which builds nothing. Tests on built fonts belong to the font project.

Compatibility

Tested on:

• Ubuntu 24.04.4 LTS, 32 cores, 32 GB of memory
  • Python 3.12.3, afdko 5.0.1, fontTools 4.68.0, cffsubr 0.4.0, uharfbuzz 0.57.0
  • Source Han Sans 2.005R
• GitHub Actions ubuntu-latest, one pool per job

Disclaimer

This project is not affiliated with, endorsed by, or sponsored by Adobe Inc. Adobe and Source are either registered trademarks or trademarks of Adobe in the United States and/or other countries and are referenced here solely for descriptive purposes.

License

Copyright 2026 Tianyu (Sky) Lu

The entire repository is licensed under the Apache License, Version 2.0 (the "License"); you may not use any file in this repository except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Author

Tianyu (Sky) Lu