fontdue 0.0.4

A simple no_std font parser and rasterizer.


Documentation Documentation License

Fontdue is a simple, no_std, pure Rust, truetype font parser and rasterizer. It aims to support all valid (unicode encoded) TrueType fonts correctly, and strives to make interacting with fonts as fast as possible. This includes: layout and rasterization.

A non-goal of this library is to be allocation free and have a fast, "zero cost" initial load. This library does make allocations and depends on the alloc crate. Fonts are fully parsed on creation and relevant information is stored in a more convenient to access format. Unlike other font libraries, the font structures have no lifetime dependencies since it allocates its own space.

Ideally, font loading should be faster in the future, but making the loading process correct and readable was the initial priority.

TrueType Table Support

  • cmap Character to glyph mapping (Unicode only)
    • Supports popular formats 0, 4, 6, 10, 12, 13
    • Planned support: formats 2, 8, 14
  • glyf Glyph outlining
    • Planned support: Compound glyph matched points, compound glyph scaled offset
  • head General font information
  • hhea General horizontal layout (Optional)
  • hmtx Glyph horizontal layout (Optional)
  • vhea General vertical layout (Optional)
  • vmtx Glyph vertical layout (Optional)
  • loca Glyph outline offsets and lengths
  • maxp Maximum values used for the font

Planned support for:

  • kern Kerning pair layout


// Read the font data.
let font = include_bytes!("../resources/Roboto-Regular.ttf") as &[u8];
// Parse it into the font type.
let mut font = fontdue::Font::from_bytes(font).unwrap();
// Rasterize and get the layout metrics for the letter 'g' at 17px.
let (metrics, bitmap) = font.rasterize('g', 17.0);


Strives to be the fastest.


Here are some benchmarks. They generate the layout metrics and bitmap for the letter 'g' are different sizes. This is going straight from the character 'g' to the metrics and bitmap, which is how the majority of people will interact with a font library and is the expected real world performance.

Fontdue: Metrics + Rasterize 'g'/20  time:   [993.07 ns 995.05 ns 997.21 ns]
Fontdue: Metrics + Rasterize 'g'/40  time:   [1.4955 us 1.4969 us 1.4987 us]
Fontdue: Metrics + Rasterize 'g'/60  time:   [2.1639 us 2.1653 us 2.1672 us]
Fontdue: Metrics + Rasterize 'g'/80  time:   [3.0232 us 3.0256 us 3.0284 us]


Other popular font library.

RustType: Metrics + Rasterize 'g'/20 time:   [11.701 us 11.719 us 11.738 us]
RustType: Metrics + Rasterize 'g'/40 time:   [18.993 us 19.036 us 19.081 us]
RustType: Metrics + Rasterize 'g'/60 time:   [27.106 us 27.188 us 27.276 us]
RustType: Metrics + Rasterize 'g'/80 time:   [37.033 us 37.177 us 37.335 us]


Inspired by how simple the wonderful rusttype crate made font parsing look (link), and how fast the font-rs crate made rasterization look (link).