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fontdone

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Latest release: 2.14.3-alpha.11.

A pure Rust font engine for glyph rendering and metrics, with selected FreeType-compatible APIs. Use it from Rust, C/C++, Node.js, or a browser. This alpha has documented compatibility limits.

Documentation · Supported features · Benchmark results

Install

Your application Distribution Guide
Rust Cargo: fontdone Rust guide
Node.js or browser npm: fontdone JavaScript guide
C/C++ SDK archive on GitHub Releases C guide

There is one public Cargo crate, one npm package, and no PyPI package. The Rust crate requires Rust 1.87 or newer.

[dependencies]
fontdone = "=2.14.3-alpha.11"

Render a glyph in Rust

use fontdone::Font;

fn render_a(font_bytes: &[u8]) -> Result<Vec<u8>, fontdone::FontError> {
    let font = Font::truetype(font_bytes, 16.0)?;
    let mask = font.getmask("A")?;
    assert_eq!(mask.pixels.len() as u64, u64::from(mask.width) * u64::from(mask.height));
    Ok(mask.pixels)
}

Pass bytes from a font you are licensed to use. The font copies the input; the mask owns its pixels. getmask and getbbox process the first Unicode scalar. getlength sums advances across the string without kerning. See the Rust guide for units, errors, ownership, and explicit glyph loading.

Is it right for my application?

  • Render glyph masks and obtain metrics through the compact Rust or JavaScript APIs.
  • Use supported FreeType-shaped functions when migrating Rust or native C code.
  • Add a separate shaping/layout layer for ligatures, bidi text, fallback fonts, and paragraphs.
  • Check the compatibility guide for font formats and partial features.

This alpha does not promise full FreeType replacement or ABI stability. Create a separate face per thread and verify the fonts and operations you use.

Performance

View benchmark results for per-operation timings. Historical and timing-only measurements remain labeled. They do not establish a universal speedup or performance on every font.

Contribute and get help

Contributing covers builds, tests, benchmark development, and reporting problems. See the contributor documentation index and measured compatibility evidence for details. Releases · Changelog · Security · Code of conduct

Fontdone is distributed under the FreeType License. See NOTICE.md for attribution.

Acknowledgements

Thank you to FreeType and its contributors for the reference implementation and public contracts, and to the authors who provide licensed test fonts.