Liberation fonts and the tricky task of internationalization

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Fedora is debating dropping the storied Liberation font family from its distribution in favor of a fork. Liberation was one of the highest-profile open fonts, but it has languished since its initial release. Licensing issues were part of the problem, but so was the subtler disconnect of Liberation's origin as a commissioned work from a proprietary company, without an interest in working with the community. But the pressures of internationalization means the community has long sought a replacement; one that it can continue to develop.

Liberation through the ages

Liberation was released in 2007 by Red Hat, who had commissioned the designs from the commercial foundry Ascender Corporation. The initial set consisted of three fonts — Liberation Sans, Liberation Serif, and Liberation Mono — specifically designed to have the same metrics as the proprietary Monotype fonts Arial, Times New Roman, and Courier New, respectively. That meant that every character in Liberation would be the exact same height and width as its counterpart in the proprietary font, and Liberation could serve as a "drop in" replacement without disturbing line breaks or pagination. In 2010, Oracle donated a fourth typeface to Liberation: Liberation Sans Narrow, which was designed to be metric-compatible with Arial Narrow.

The Liberation family was regarded as high-quality, but it covered only the Latin, Greek, and Cyrillic alphabets, which left a lot of writing systems unaddressed. That alone is not a problem; fonts can — and are — extended to new writing systems frequently. But Liberation was licensed under unique terms, which inadvertently prevented such expansion.

Originally, the license was the GPLv2 with the Free Software Foundation's standard font embedding exception (which specifies that embedding the font in a PDF or similar document does not make the document itself a "combined work" triggering the GPL). However, Red Hat subsequently appended additional clauses to the license covering trademark and intellectual property concerns, and included a custom anti-Tivoization provision. After an examination of the extra clauses, Debian decided that they constituted additional restrictions on the GPLv2, which made the license self-contradictory and the fonts impossible to redistribute. The FSF reportedly found the Liberation license not to be a self-contradicting paradox, but said it was incompatible with the GPL. Furthermore, in recent times the GPL-with-font-embedding-exemption approach has fallen out of favor as an open font licensing choice, largely in favor of the SIL Open Font License (OFL). Fedora is aware of this shift, and now recommends the OFL for font projects.

Regardless of the exact details, however, the general consensus was that Liberation's peculiar license was, at best, problematic. More importantly, the practical upshot that few people were interested in contributing new character sets. The fonts have essentially remained unchanged since 2007. Minor fixes and isolated characters have been added, but no entirely new scripts.

Replacement plan

But the metric-compatibility feature of Liberation was its main selling point: it enabled Linux users to share documents with colleagues that had the popular Monotype fonts installed (e.g., all Windows systems), while ensuring compatibility.

On May 17, Parag Nemade emailed the Fedora-devel list to request packaging the Croscore family as a default, to serve as an alternative to Liberation. The Croscore family covers all of the same language blocks as Liberation, plus several new ones (such as Hebrew, Pinyin, and many African alphabets). It consists of three fonts: Arimo, Tinos, and Cousine, which also offer metric compatibility with Monotype's Arial, Times New Roman, and Courier New.

They were commissioned by Google for use in ChromeOS, and not only are they also the work of Steve Matteson, the same designer who created Liberation, but they are in fact a more recent version of the exact same designs. In an amusing bit of irony, however, Ascender Corporation (Matteson's company) was acquired by Monotype in 2010, so the new font family is copyrighted by Monotype, but designed to replace other Monotype fonts.

More to the point, however, Google made Croscore available under the OFL, which makes it simpler for outside contributors to extend the fonts to new character sets. Following the discussion in Nemade's thread, Fedora font packager Pravin Satpute proposed importing the Croscore sources into the Liberation package, replacing the problematically-licensed content rather than starting a separate package.

The Fontconfig package handles automatic font substitution on Linux, so once a change is pushed through with rules that replace (for example) Courier New with Croscore's Cousine instead of Liberation Mono, the only remaining hurdle will be for users to get used to the new names in the "Font" menu. On the other hand, growing the fonts to extend coverage to new writing systems is not trivial. The OFL license makes it easier; it enables developers to import and reshape glyphs from the large assortment of other OFL-licensed fonts.

What makes all this so difficult, anyway?

The Fedora plan calls for the community to continue development on the "Liberation 2.0" series, in the open, where the original Liberation was not. It would probably be a minor story if it were not for the fact that the same stalemate situation has developed for other open font commissions.

Much the same sequence of events befell the Bitstream Vera font family, which was designed by Bitstream (another commercial foundry which has since been acquired by Monotype) for the GNOME Foundation, and released in 2003. It, too, was under a license unique to the project, and has not seen any significant updates since its original release. Google has commissioned two fonts for distribution with Android: the familiar Droid family and the newer Roboto; both licensed under the Apache License (as is most of Android itself). Both offer wide language coverage in at least one of the faces (the sans serif), but have not otherwise seen significant expansion.

About the only open font commissioned from a commercial foundry that has grown to include more languages and alphabets is the Ubuntu font family designed by the Dalton Maag foundry. Although the details are of course private, Dalton Maag has an ongoing arrangement with Canonical to add more character sets over time. But the project does use a public issue tracker and accepts input and feedback from the user community, which none of the other commercial font commissions do.

Those differences are revealing. Commissioned open font projects such as Liberation and Bitstream Vera invariably attract significant attention — as do large "donations" of other types to open source. But when they are delivered in a self-contained bundle and not developed further, they have far less impact. It is easy for those of us who natively read European languages to forget just how many writing systems are not covered by basic Latin, Greek, and Cyrillic. Meanwhile, there are purely community-driven font projects that do cover far more of the globe's writing systems, such as Linux Libertine or DejaVu (the latter of which extends Bitstream Vera, side-stepping the peculiar Bitstream license by releasing its changes into the public domain).

The perception among the public is that the commercial fonts are of higher quality than the community-built fonts; a charge likely to rankle anyone who works on free software professionally. But by choosing non-standard licenses and not establishing the font as a software package that can be studied and patched, the early commercial commissions made that charge difficult to disprove. The problem is exacerbated when the foundry is uninterested in continuing to participate (as Bitstream was, when it said it was only interested in extending Vera if it were paid to do so).

But stagnation is detrimental to a font package just as it is to any software. Not only can every font be extended to cover more languages, but there are updated technologies like OpenType features and the Web Open Font Format (WOFF) to consider. Adding new character sets to a font is clearly a challenging task, demanding familiarity with multiple alphabets, and often requiring patches to be integrated by hand in a tool like FontForge. Hopefully the re-started Liberation 2.0 effort can draw on the lessons learned by Dalton Maag and DejaVu, and grow a sustainable project around the family. The original Liberation fonts filled a vital gap on Linux desktops and watching them languish has been disconcerting. Liberation now has the opportunity to re-import an entire codebase under a better license than the one that has hampered it for five years; few projects get a chance to start over at that same level — this is one that at least deserves to take a second shot.