1. By default, Source Sans builds OpenType fonts, which is what I have currently packaged. However, it also has the option of converting these to the older TrueType format. Some of the advanced layout information is lost in the TrueType format. OpenType seems well supported by software that consumes fonts, and with only a few exceptions, I don’t see many Debian font packages shipping both OpenType and TrueType fonts. Is there any reason that I should ship the TrueType fonts in 2024 if upstream supports OpenType?
There's a fairly common misconception buried in here: the .ttf fonts contain the exact same functionality as the .otf fonts. The filename extension does not tell you what OpenType Layout (or other smart features) are present. It only _nominally_ tells you if the Beziers are quadratic or cubic (and even that is just by convention). This is the case for many, many existing fonts packaged for Debian that have the .ttf filename extension.
I suspect that there are cases where one rendering environment or another doesn't support cubic Beziers — especially in legacy code — and that is why so many upstream foundries provide both of them. I know from other projects that it has been a longer road to get certain variable-font mechanics to work correctly with the cubic (CFF-table) contour format, but that is largely because CFF is rarely produced in production outside of Adobe, since it came from PostScript. The quadratic (glyf-table) format has been the vast majority of variable fonts because of that.
2. Upstream defaults to building standard OpenType fonts, but it has the option to build the VF (Variable Font) format, which combines several font binary files into one. I noticed that a few packages ship OpenType VF fonts, but none in the font directory that I easily discovered. I am assuming that, at least currently, there is no benefit to shipping the VF format in a font package in Debian.
Variable fonts are well supported throughout the free software stack these days. There are different levels of defining "support", but the critical question of making Named Instances appear and be usable in system font menus has been a "yes" for quite some time, from Fontconfig right up through desktop office and libre graphics apps (in addition to browsers, of course). They're a real plus if you can succeed in getting them to build, particularly for design work. I'd say go for it, wholeheartedly! Users will appreciate it.
Nate
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