Hi all,

CONTEXT

I've now spent several years redoing font packaging automation in Fedora, culminating with this guideline change proposal: https://pagure.io/packaging-committee/pull-request/934

It should soon be dead easy to package industrial quantities of nice OFL fonts Fedora-side, without giving up on quality, right?

Unfortunately, no. Font files have gotten a lot more complex in the past decade. But font authors are no more careful than they were in the past. Thus, the amount of fixing required fontconfig-side has grown.

However, the fontconfig language is little more expressive today, than it was a decade ago. Despite Fedora shipping fontconfig templates maintained by Akira himself, our fontconfig state is, at best, poor.

PROPOSAL

I would like the fontconfig project to consider a configuration language update based on the following proposal: https://gitlab.freedesktop.org/fontconfig/fontconfig/issues/200

It is based on the experience, gained, analysing hundreds of Fedora fontconfig files, while streamlining the corresponding packaging.

This update is a mix of: – syntax sugar enhancements – tweaked fontconfig engine behaviour – new features

It is presented both in traditional XML, and in YAML.

The proposal is only intended as documentation of the kind of thing that would be useful to fontconfig users. I don’t care if this exact syntax is adopted, or if it’s only partially implemented. Please provide something that does the kind of thing I documented.

The current fontconfig syntax is awkward for simple traditional font projects, and does not scale at all to the level required for modern complex font project.

CONCISENESS

The proposal results in drastically more succinct config files, which are easier to write, review and maintain. Conciseness is its own feature.

For example, the description of IBM Plex Sans takes 106 lines in the XML variant, and 27 lines in the YAML Variant. That may seem awful, but my current incomplete attempt to describe Plex Sans with today’s fontconfig syntax is more than 1700 lines long.

Given what I know of today’s fontconfig syntax, this attempt will never achieve what’s in the proposal. The necessary logic is missing in the fontconfig engine. It's not just a templating problem.

And, the missing logic is not complex. fontconfig is very close to where it should be engine-side. Little things just snowball out of control in presence of complex font projects.

Plex is not a pathological font project. On the contrary, it’s well funded, and its authors clearly try to do the right thing. But, Plex is modern, complex font project. That leaves a lot of room for small mistakes.

ORDERING INDEPENDANCE

The proposal results in largely order-independant config files, removing the need to agonize over proper ordering and ordering side- effects, and removing the need to split configuration for a font family over multiple files (that required specifying engine behaviour tweaks).

CORRECT ABSTRACTION LEVEL

The proposal avoids over-specifying low-level fontconfig behaviour, leaving room to tweak the logic when new lessons are learnt, without requiring the rewrite of thousands of configuration lines spread over hundreds of files.

DOING THE CORRECT THING BY DEFAULT

The proposal makes some fixes automatic (generally, just applying OpenType recommendations), so they're not forgotten half the time, and we can all focus on more interesting things.

COMPATIBILITY

The proposal is backwards-compatible.

I hope you’ll find it interesting.

Best regards,