Leon Sans 2.0

Leon Sans is a geometric variable sans-serif typeface designed by Jongmin Kim. Originally created in 2019 as a code-based drawing system to celebrate the birth of his son Leon, Version 2.0 is a standalone OpenType variable TrueType family (LeonSans[wght].ttf) spanning a continuous wght axis from 100 (Thin) to 900 (Black).

Interactive Type Specimen & 470-Glyph Preview → https://leon-kim.com/preview/

This repository contains the installable variable font, editable UFO masters, and reproducible open-source build pipeline. The original animated JavaScript drawing library is maintained separately at cmiscm/leonsans.

Overview & Specification

• File: fonts/variable/LeonSans[wght].ttf
• Family Name: Leon Sans (Version 2.000, 2000 UPM)
• Variable Axis: wght 100–900 interpolated from 8 editable UFO masters (100, 300, 400, 500, 600, 700, 800, 900) with 9 named instances (Thin, ExtraLight, Light, Regular, Medium, SemiBold, Bold, ExtraBold, Black). The default variable instance is Regular (400).
• Character Repertoire (470 Glyphs):
  • Basic & Extended Latin: Google Fonts Latin Core plus pan-European Latin-1, Latin Extended-A/B, stroked letters (Ø ø Ł ł Đ đ Ħ ħ), ligatures (Æ æ Œ œ ß ẞ fi fl), and combining marks.
  • Harmonized Figures & Fractions: Optically balanced lining figures (0–9), full superscripts (⁰–⁹) and subscripts (₀–₉), and vulgar fractions (¼ ½ ¾ ⅓ ⅔).
  • Currencies, Arrows & Calculus: International currency symbols (€ £ ¥ $ ₹ ₩ ¢), geometric arrows (← ↑ → ↓ ↔ ↖ ↗ ↘ ↙), mathematical and calculus operators (π Ω ∑ ∏ √ ∞ ∫ ∂ ∆ ∅ ≈ ≠ ≤ ≥ ÷ × ±), and enclosed/editorial symbols (Ⓓ © ® ™ № ℓ § ¶ † ‡).

Build from Source

Python 3.12+ is supported for building from source using the pinned open-source toolchain:

python -m venv .venv
source .venv/bin/activate
python -m pip install -r requirements.txt
python scripts/build.py

The eight editable UFO masters and LeonSans.designspace are located in sources/. fontmake compiles the variable TTF, and scripts/finalize.py applies STAT/OS/2/name table metadata, IUP-safe 2000-UPM scaling, and non-hinting rasterizer tables (prep/gasp). No proprietary font editor or external binary is required.

To run Google Fonts QA checks:

fontbakery check-googlefonts 'ofl/leonsans/LeonSans[wght].ttf'

Version 2.0 Highlights

• Continuous wght Axis (100–900): Re-engineered from 8 UFO masters on a 2000-UPM grid.
• Optical Curve-to-Stem Transitions: Refined inner and outer bowl joins across weights 300–900 (a, b, d, g, p, q, u, y, 5, 6, 9, @ and accented derivatives) for smooth, natural curvature without pinch points.
• Harmonized Numerals: Unified figure proportions, crossbar alignments, and curve geometry across 0–9 and derived superscripts, subscripts, and fractions.
• OpenType Layout: ccmp canonical composition and contextual dotless forms (i, j, iogonek before top marks), liga standard ligatures, kern pair kerning, and mark/mkmk anchor positioning.

Version 1 static font binaries remain available in Git history.

License & Authorship

Copyright 2019 The Leon Sans Project Authors (https://github.com/cmiscm/leonsansfont). Licensed under the SIL Open Font License 1.1.

Interactive Type Specimen (leon-kim.com/preview/) · Designer Website · Google Fonts PR #11132 · Issue #2169