ufoLib2

library0.18.1pypypi✓ verified 85d ago

ufoLib2 is a UFO font processing library for reading, writing, and manipulating Unified Font Object (UFO) files. It provides Python objects for font, layer, glyph, and other UFO structures with lazy loading and efficient serialization. Current version: 0.18.1. Requires Python >=3.9. Maintained by the fonttools project; release cadence is irregular with several minor releases per year.

serialization data

pip install ufoLib2

github ↗package ↗

INSTALL

IMPORT

SIG · UFOLIB2

ufoLib2

serializationpythonv0.18.1

Install

3.0s avg

Import

384ms

Disk

44MB

Pass rate

10/ 10

Env Coverage10 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v0.18.1 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

py 3.10–3.915 runs

installs and imports cleanly · install 0.0s · import 0.404s · 43.3MB

glibc

py 3.10–3.915 runs

installs and imports cleanly · install 3.0s · import 0.364s · 47MB

44MB installed

● package 44MB

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

Font

✓ from ufoLib2 import Font

✗ from ufoLib2.objects import Font

Font is exported at package level since v0.10.0; direct import from objects works but is not recommended.

Glyph

✓ from ufoLib2.objects import Glyph

✗ from ufoLib2 import Glyph

Glyph is not exported at package level; must import from ufoLib2.objects.

Layer

✓ from ufoLib2.objects import Layer

✗ from ufoLib2 import Layer

Layer is not exported at package level; must import from ufoLib2.objects.

Create a new UFO font, set unitsPerEm, save to a temporary directory, then reopen it.

from ufoLib2 import Font # Create a new font font = Font() font.info.unitsPerEm = 1000 # Save to a temporary path (will create .ufo directory) import tempfile with tempfile.TemporaryDirectory() as tmpdir: ufo_path = f"{tmpdir}/MyFont.ufo" font.save(ufo_path) print(f"Saved to {ufo_path}") # Open an existing UFO font2 = Font.open(ufo_path) print(font2.info.unitsPerEm)

Debug

Known issues

breakingPython 3.8 support dropped in v0.18.0. Use Python >=3.9.

fix

Upgrade Python to 3.9 or later.

affects: >=0.18.0

deprecatedThe 'fs' module (import fs) will be removed; replaced with tempfile.TemporaryDirectory. Do not rely on fs internals.

fix

Replace usage of tempfs with tempfile.TemporaryDirectory.

affects: >=0.18.0

gotchaFont objects are lazily loaded by default. Modifying glyphs or layers may require explicit loading.

fix

Access properties or call .load() to trigger loading. Use Font.open(ufo, lazy=False) to disable lazy loading.

affects: all

gotchaSaving a UFO creates a directory (UFO format) not a single file. Ensure the save path ends with .ufo and the parent directory exists.

fix

Use font.save('/path/to/MyFont.ufo') which creates a directory.

affects: all

breakingcattrs minimum version upped to 1.10.0 as of v0.13.1. Older cattrs may cause errors with converters.

fix

Ensure cattrs >=1.10.0 is installed if using converters extra.

affects: >=0.14.0

deprecatedUse of 'from ufoLib2.objects import Font' is discouraged; prefer 'from ufoLib2 import Font'.

fix

Change import to 'from ufoLib2 import Font'.

affects: all

Errors

Common errors & fixes

ModuleNotFoundError: No module named 'ufoLib2'

Library not installed.

fix

pip install ufoLib2

AttributeError: module 'ufoLib2' has no attribute 'Glyph'

Glyph is not exported at package level.

fix

from ufoLib2.objects import Glyph

TypeError: save() takes 1 positional argument but 2 were given

Trying to save with a file path as argument without keyword? Actually save only takes the path as positional.

fix

font.save('/path/to/font.ufo')

ufoLib2.errors.UFOError: Invalid UFO version: 3

UFO file has format spec version that is not supported or malformed.

fix

Ensure the UFO is valid; check ufo/lib/formatversion.txt. ufoLib2 supports UFO v3 and v2.

ImportError: cannot import name 'Font' from 'ufoLib2.objects' (unknown location)

Wrong import path or outdated version.

fix

Use 'from ufoLib2 import Font' instead.

Upgrade

Version history

0.18.1latest on PyPI · released Jul 10, 2025

Audit

Dependencies

fonttoolsrequiredRequired for UFO data structures and glyph drawing

fsrequiredUsed internally for filesystem abstraction (deprecated as of 0.18.0, replaced by tempfile.TemporaryDirectory)

Agent activity

27 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/fonttools/ufoLib2 ↗

packagehttps://pypi.org/project/ufoLib2/ ↗