January 17th, 2017

Using San Francisco font in Swing applications on a Mac

Starting from OS X El Capitan (10.11), there’s a new default system font in town – San Francisco. And it came with a very big underlying change, as detailed by Craig Hockenberry:

Apple has started abstracting the idea of a system font: it doesn’t have a publicly exposed name. They’ve also stated that any private names are subject to change. These private names all begin with a period: the Ultralight face for San Francisco is named “.SFNSDisplay-Ultralight”. To determine this name, you need to dig around in the font instances returned by NSFont or UIFont; it’s not easy by design.

The motivation for this abstraction is so the operating system can make better choices on which face to use at a given weight. Apple is also working on font features, such as selectable “6” and “9” glyphs or non-monospaced numbers. It’s my guess that they’d like to bring these features to the web, as well.

Even though the underlying .otf files are still in /System/Library/Fonts, San Francisco is no longer exposed via the regular APIs that web and desktop developers have grown used to. Specifically for Swing developers (of which there may not be many, so at some point it will kind of take care of itself), passing “San Francisco” to the Font constructor ends up using the previous default – Lucida Grande.

JavaFX is already doing the right thing, using San Francisco as the default UI font on El Capitan and Sierra. Swing’s legacy is to have each look-and-feel decide which font to use, and I was expecting the “System” look-and-feel which maps to Aqua to be using the right font family on the latest OS releases. That is not the case as I’m writing this entry, and Swing apps on both El Capitan and Sierra are still using Lucida Grande on both 8u112 and 9-ea.

Last week Phil Race pointed me to this issue that tracked syncing up the internal implementation details of glyph mapping between JavaFX and AWT. That issue has been fixed in early access builds of JDK 9, and is slated to be available in JDK 8 u152 scheduled for October 2017. At the present moment there is no public API to get either a name or a font instance itself that will be mapped to Lucida Grande on 10.10 and earlier, and to San Francisco on 10.11 and 10.12. The only available solution is quite brittle as it depends on the internal naming conventions exposed by the underlying OS:

  • .Helvetica Neue DeskInterface on El Capitan (10.11)
  • .SF NS Text on Sierra (10.12)

Note that you need a leading dot in both cases, and that this only works on early access builds of JDK 9 at the moment:

In this screenshot the second button is using new Font(“.SF NS Text”, Font.PLAIN, 24) while the rest are rendered with Lucida Grande. The most noticeable differences are in the curvy strokes of “e”, “g”, “5” and “9”, as well as the straight leg of “a”.

Ideally, there’d be an officially supported way to use the right font on OS X / macOS, either in a form on some kind of a static Font API or a synthetic font family that maps to the underlying system font on all supported platforms. Phil has filed a bug to track the progress on that front.