cffsubr

library0.4.0pypypi✓ verified 86d ago

A standalone CFF (Compact Font Format) subroutinizer based on the AFDKO tx tool. It converts CFF fonts to their subroutinized form, reducing file size. Version 0.4.0 requires Python >=3.10. Releases are irregular; maintained by Adobe Type Tools.

serialization data

pip install cffsubr

github ↗package ↗

INSTALL

IMPORT

SIG · CFFSUBR

cffsubr

serializationpythonv0.4.0

Install

2.6s avg

Import

116ms

Disk

44MB

Pass rate

5/ 10

Env Coverage5 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v0.4.0 · 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 3.10–3.95 runs

build_error

glibc

py 3.10–3.95 runs

installs and imports cleanly · install 2.6s · import 0.116s · 46MB

44MB installed

● package 44MB

Code

Verified usage

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

subroutinize

✓ from cffsubr import subroutinize

✗ from cffsubr.cffsubr import subroutinize

cffsubr is a single module; no submodule.

Load a CFF font, subroutinize it, and save.

from cffsubr import subroutinize from fontTools.ttLib import TTFont font = TTFont('input.otf') subroutinize(font) font.save('output.otf')

cffsubr --version

Debug

Known issues

breakingIn cffsubr 0.4.0, the `subroutinize` function must be called on a TTFont object; it no longer accepts raw bytes or file paths.

fix

Use fontTools to load the font first: TTFont('path.otf').

affects: >=0.3.0

gotchaOnly CFF-flavored OpenType fonts (.otf) are supported. TrueType-flavored fonts (.ttf) will not be processed.

fix

Ensure the input font has CFF outlines (check with TTFont.sfVersion == 'OTTO').

affects: all

gotchaThe `subroutinize` function modifies the font object in place; it does not return a new font or any status code.

fix

After calling, the original font object is modified. Save a copy first if needed.

affects: all

Errors

Common errors & fixes

AttributeError: module 'cffsubr' has no attribute 'subroutinize'

Importing from the wrong path or using an old version where the function was named differently.

fix

Use `from cffsubr import subroutinize` and ensure cffsubr >= 0.2.0.

TypeError: subroutinize() missing 1 required positional argument: 'font'

Called without passing a TTFont object.

fix

Pass a loaded TTFont instance: `subroutinize(font)`.

fontTools.ttLib.TTLibError: Unknown font format

Input file is not a valid OpenType font (e.g., .ttf, .woff, or corrupt file).

fix

Verify the font is a CFF-based .otf file.

Upgrade

Version history

0.4.0latest on PyPI · released Dec 5, 2025

Audit

Dependencies

fonttoolsrequiredUsed to load and manipulate font objects.

Agent activity

15 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/adobe-type-tools/cffsubr ↗

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