fontcull

A Rust port of the parts of glyphhanger I use regularly.

Why?

glyphhanger is amazing, but it's 5+ years old and requires a specific old version of Chrome/Puppeteer that's become painful to maintain. With the help of Claude, I ported the core functionality to Rust.

What it does

1. Opens URLs in a headless browser (via chromiumoxide)
2. Extracts all glyphs/characters used on the page (including ::before/::after pseudo-elements)
3. Optionally spiders the site to find more pages
4. Subsets font files to only include the characters actually used

Usage

# Just get the unicode range of characters used
fontcull https://example.com

# Subset fonts based on page content
fontcull https://example.com --subset=fonts/*.ttf

# Spider multiple pages
fontcull https://example.com --spider-limit=10 --subset=fonts/*.ttf

# Filter by font family
fontcull https://example.com --subset=fonts/*.ttf --family="My Font"

# Add extra characters to always include
fontcull https://example.com --subset=fonts/*.ttf --whitelist="0123456789"

Subsetting backends

• klippa (default): Pure Rust subsetting via fontations, woff2 compression via vendored Google woff2
• pyftsubset (--pyftsubset): Falls back to Python's fonttools (requires pip install fonttools brotli)

Install

cargo install --git https://github.com/bearcove/fontcull

Requires Chrome/Chromium installed (uses your system browser, no specific version needed).