Rubrail is a Rust library for building Touch Bar interfaces for Mac OS X.
It creates a persistent icon in the 'Control Strip' region on the right side of the touchbar. This lets you access a Touch Bar menu of your design at any time, regardless of which application is currently active.
Using a pure-Rust API, you can create Touch Bar UIs with the most common items: Buttons, Labels, Sliders, Scrubbers (horizontally scrolling text selections), and recursive menus.
Source for following screencast in examples/example.rs
$ cargo test && cargo run --example example
Note that access to the Control Strip is forbidden by Apple's guidelines. Rubrail uses private APIs to create its menus, and thus is not suitable for distribution through the App Store. A 'dummy' implementation is provided for apps that want to provide Touch Bar support, but want the ability to avoid linking against private frameworks when distributing. Build with the --no-default-features Cargo flag to get a dummy implementation that does nothing.
To communicate with the Touch Bar service, apps using Rubrail must be executed from an app bundle (.app). Running the executable directly will not crash, but the icon will not be registered with the Touch Bar service, so your Touch Bar UI will be unavailable.
The included example uses the fruitbasket crate to automatically re-launch itself as an OS X app bundle.
There is no support for changing the UI of an existing bar. To change the UI layout, you must create a new bar and completely replace the old one. Scrubbers are an exception: their contents are managed by callbacks, but they do not live-refresh when the bar is visible. The user must close and re-open the bar to see scrubber content changes.
The Touch Bar API supports doing just about anything with custom views. Rubrail does not. Only a very limited set of UI options are exposed.
Rubrail links against the private Apple framework DFRFoundation.framework. This is handled by adding the private framework path in build.rs. Applications that use Rubrail do not need to link against it themselves, but should be aware that a dependency does.
Linking requires an XCode version high enough to support the Touch Bar and the private framework. The only tested version of XCode is version 8.3. Applications that use Rubrail must build with a new enough XCode version. If using Travis-CI, this means adding a line like this to your .travis.yml:
osx_image: xcode8.3