mobile-ink notes surface

[markm39]

First of all, thank you for the amazing work on React Native Skia. It is one of the most important libraries in the React Native ecosystem, and the fact that it makes Skia realistically accessible from RN is a huge part of why this project is possible.

I wanted to share something I’ve been working on: a Notability/GoodNotes-style drawing engine for React Native.

Selection editing

Large notebook performance

Repo: https://github.com/mathnotes-app/mobile-ink
npm: https://www.npmjs.com/package/@mathnotes/mobile-ink

Mobile Ink is an iOS-first native drawing engine for notes-app workloads. Apple Pencil input, smooth strokes, pixel erasing, selection, shape recognition, serialization, preview export, zoom/scroll, and continuous multi-page notebooks.

The UI layer is React Native, but the actual ink surface is a custom native MTKView backed by a C++ Skia drawing engine. It depends on react-native-skia for Skia native libraries/headers, but it does not render the drawing surface through React Native Skia’s React <Canvas> API.

I started building this because I couldn’t find an open-source mobile drawing/canvas engine that handled the kind of stress a real notes app needs: long documents, fast page crossing, Pencil latency, native memory pressure, and smooth interaction while editing.

I’d love feedback from people who know Skia/native rendering, especially around:

• selection transform performance for large stroke groups
• eraser cursor/native state lifecycle
• architecture/API shape for large canvases and multi-page notebooks
• ways I can make the package more useful to the React Native/Skia community

Thanks again for all the work on this library. Happy to share more details about the architecture if useful.