I would love to see Lagrange running on all kinds of devices. Using C and SDL makes this achievable — exhibit A: the app on 2017 iPad Pro.
The more mobile things get, the more one needs to adapt the UI and behavior. You get a lot of stuff for free with native UI components, but with custom UI and SDL there's none of that.
Just getting the code to run is the easy part, and I'm happy to report that it runs smoothly.
@makeworld Yeah SDL is great library, and thanks to Gemini being limited in scope it's feasible to implement a fully custom UI from scratch.
Of course there are drawbacks, too... Things like accessibility and localization also have to be done from scratch. Mobile OS's have tons of custom APIs for various features, and a well-behaving app should use them as intended. SDL provides some basic things, but it's still quite a hurdle.