glyphore

Glyph PBF (SDF) generator for MapLibre GL styles. Build static glyph directories with the CLI, or generate individual 256-codepoint ranges on demand from Rust, browsers, and Node.

The range API is designed for live style editors such as Kartore: drop a font file and make it available immediately, without a separate glyph build and hosting step.

Install

JavaScript

pnpm add @kartore/glyphore

Rust with Cargo

Add the Rust API without the CLI dependency:

cargo add glyphore --no-default-features

Use the lower-level engine directly when building another integration layer:

cargo add glyphore-core

Install the native command-line interface with Cargo:

cargo install glyphore

CLI

Build every covered glyph range from the TTF and OTF files in a directory:

npx @kartore/glyphore build fonts/ -o glyphs/
npx @kartore/glyphore info fonts/NotoSans-Regular.ttf

The output uses each font's internal fontstack name as its directory, including spaces: glyphs/Noto Sans Regular/0-255.pbf. Only ranges containing mapped glyphs are written; unlike build_pbf_glyphs, empty ranges are omitted.

These per-font directories are directly usable with a single-entry text-font array. MapLibre joins multiple text-font entries with commas when expanding {fontstack}; glyphore does not generate those combined directories.

The native CLI installed through Cargo offers the same commands and output layout:

glyphore build fonts/ -o glyphs/

For GitHub Actions, the build can run with Node alone:

steps:
  - uses: actions/checkout@v4
  - uses: actions/setup-node@v4
    with:
      node-version: 24
  # Pin glyphore so the generator cannot change when the latest tag advances.
  - run: npx --yes @kartore/glyphore@0.2.0 build fonts/ -o glyphs/

Generated PBF files contain data derived from the source font. Check the font's license before redistributing them.

Browser

import { generateRange, loadFont } from "@kartore/glyphore";

{
	using font = await loadFont(fontBytes);
	// U+0000–U+00FF. Range starts must be multiples of 256.
	const pbf = generateRange(font, 0);
	console.log(font.info.fontstackName, pbf);
}

Use [font.info.fontstackName] as a symbol layer's text-font array. With that single entry, MapLibre substitutes the same name for the glyph URL's {fontstack} placeholder. font.info.coveredRanges contains the sorted range starts that have at least one glyph.

The using declaration releases the loaded font when its scope exits. For Node, import loadFont and generateRange from @kartore/glyphore/node; it reads the bundled WebAssembly file automatically. See the package README for complete browser and Node examples.

Rust

use glyphore::{FontFace, generate_range};

fn main() -> Result<(), Box<dyn std::error::Error>> {
	let bytes = std::fs::read("NotoSans-Regular.ttf")?;
	let face = FontFace::parse(&bytes)?;
	let pbf = generate_range(&face, 0)?;
	std::fs::write("0-255.pbf", pbf)?;
	Ok(())
}

See the glyphore API documentation for feature selection and the low-level glyphore-core API documentation for direct core usage.

Development

cargo fmt --check
cargo clippy --workspace -- -D warnings
cargo test --workspace
pnpm build
pnpm typecheck
pnpm test

License

Licensed under either of Apache License, Version 2.0 or MIT license at your option.