svg2ttf

Convert a legacy SVG font into a binary TrueType (TTF) font.

The crate reads an SVG document that contains a <font> element with <glyph> and <missing-glyph> children, normalizes each glyph outline, reduces cubic Beziers to quadratics, and writes the eleven SFNT tables (GSUB, OS/2, cmap, glyf, head, hhea, hmtx, loca, maxp, name, post) with their offsets and checksums.

Installation

[dependencies]
svg2ttf = "0.2"

Usage

use svg2ttf::{svg2ttf, Options};

let svg = std::fs::read_to_string("font.svg")?;
let ttf = svg2ttf(&svg, &Options::default())?;
std::fs::write("font.ttf", ttf)?;
# Ok::<(), Box<dyn std::error::Error>>(())

The single entry point is svg2ttf(svg: &str, options: &Options) -> Result<Vec<u8>, Error>.

Options

All fields are optional. Each text field overrides a value derived from the SVG font. Precedence is the option, then the SVG value, then a built-in default.

Field	Effect
id	Font id.
family_name	Family name. Falls back to the SVG family, then the id.
copyright	Copyright string. Falls back to the SVG metadata.
description	Description. Defaults to a fixed line.
url	Vendor url. Defaults to a fixed url.
subfamily_name	Subfamily name (name id 2). Defaults to Regular.
full_name	Full name (name id 4) and PostScript name (id 6).
version	Version string. Must match Version x.y or x.y.
timestamp	Unix timestamp in seconds. Fixes the head created and modified dates.

Reproducible output

The head created and modified dates are the only part of the output that depends on anything besides the input. Set timestamp to fix them, and the same SVG and the same timestamp always produce the same bytes. Without timestamp the dates use the current time.

Errors

svg2ttf returns an Error, an enum with a variant per failure cause. It fails when the SVG has no <font> tag, the <font> has no <font-face>, a glyph lacks a path, the version option is malformed, or a glyph coordinate falls outside the signed 16-bit range. Match on the variant to branch on the cause. The Display text stays stable for showing to a user.

License

Licensed under the MIT license.