Sourcerer

Sourcerer is a modified font based on Source Serif 4, optimized for e-readers.

The original Source Serif 4 variable font is located in src and is available under the same OFL as the end result, which is included in LICENSE.

Downloads

Two versions are generated via the pipeline of the latest release:

• KF_Sourcerer.zip — Kobo-optimized TrueType fonts with a legacy kern table and KF prefix. Use this if you have a Kobo e-reader, this version contains optimizations made with Kobo Font Fix.
• Sourcerer.zip — The standard, unmodified fonts, as TrueType files. Useful for other e-readers and use on your desktop computer or smartphone.

Project structure

• src: Source Serif 4 variable font TTFs
• build.py: The build script to generate Sourcerer
• LICENSE: The OFL license
• COPYRIGHT: Copyright information, later embedded in font
• VERSION: The version number, later embedded in font

After running build.py, you should get:

• out/ttf: final TTF fonts
• out/kf: Kobo-optimized KF variants

Building

Use the prebuilt fntbld-oci container:

podman run --rm -v "$PWD":/work -w /work \
  ghcr.io/nicoverbruggen/fntbld-oci:latest \
  python3 build.py

The build script uses fontTools, FontForge, and ttfautohint from the container to transform the Source Serif 4 variable fonts into Sourcerer. The pipeline instances Regular, Bold, Italic, and Bold Italic; applies Sourcerer's metrics and outline fixes; exports hinted TTFs; post-processes style flags and the lowercase e glyph; and generates Kobo KF_ variants via Kobo Font Fix.