/fontations

Reading and writing font files

Primary LanguageRustApache License 2.0Apache-2.0

Fontations

This repo contains a number of foundational crates for reading and manipulating OpenType font files. It is motivated by a desire to have more robust and performant open tools for a variety of font engineering and production tasks. For an overview of the motivations, see googlefonts/oxidize.

structure

Currently, this repo contains three main library crates: font-types, read-fonts, and write-fonts, in addition to one binary crate, otexplorer:

  • font-types contains common definitions of the core types used in the OpenType spec. This is a small crate, and is intended as a basic dependency for any project reading or manipulating font data.
  • read-fonts contains code for parsing and accessing font files. It is intended to be a high performance parser, suitable for shaping. In particular this means that it performs no allocation and no copying.
  • write-fonts contains code for modifying and writing font data. It contains owned types representing the various tables and records in the specification, as well as code for compiling these and writing out font files. It has an optional dependency on read-fonts, in which case it can also parse font data, which can then be modified and written back out to disk.
  • otexplorer is a binary crate for exploring the contents of font files. It is developed as a debugging tool, and may also be useful as an example of how the read-fonts crate can be used.

codegen

Much of the code in the read-fonts and write-fonts crate is generated automatically. Code generation is performed by the font-codegen crate. For an overview of what we generate and how it works, see the codegen-tour. For an overview of how to use the font-codegen crate, see the readme at font-codegen/README.md.

contributing

We have included a few git hooks that you may choose to use to ensure that patches will pass CI; these are in resources/githooks.

If you would like to have these run automatically when you commit or push changes, you can set this as your git hooksPath:

git config core.hooksPath "./resources/githooks"

note: If you wish to use the hooks on macOS, install the gnu coreutils (brew install coreutils, via homebrew.)

releasing

We use cargo-release to help guide the release process. It can be installed with cargo install cargo-release. You may need to install pkg-config via your package manager for this to work.

Releasing involves the following steps:

  1. Determine which crates may need to be published: run cargo release changes to see which crates have been modified since their last release.

  2. Determine the new versions for the crates.

    • Before 1.0, breaking changes bump the minor version number, and non-breaking changes modify the patch number.
  3. Update manifest versions and release. ./resources/scripts/bump-version.sh orchestrates this process.

    • cargo release does all the heavy lifting
    # To see usage
    ./resources/scripts/bump-version.sh
    # To do the thing
    ./resources/scripts/bump-version.sh read-fonts write-fonts patch
  4. Commit these changes to a new branch, get it approved and merged, and switch to the up-to-date main.

  5. Publish the crates. ./resources/scripts/release.sh orchestrates the process.

    • You will be prompted to review changes along the way
    # To see usage
    ./resources/scripts/release.sh
    # To do the thing
    ./resources/scripts/release.sh read-fonts write-fonts