The Ink library is a freehand stroke generation library. It produces smoothed, modeled stroke shapes with brush effect shaders as mesh-based vector graphics.

This library provides the core of the implementation of the Android Jetpack Ink module, which is currently in alpha. While the implementation is well-tested, the developers of this library are not currently making hard guarantees about interface stability. We probably will attempt to introduce a versioned release process after the Jetpack module stable release.

• Bazel 7: https://bazel.build/install
• Android NDK: https://developer.android.com/ndk/downloads
  • Download and set ANDROID_NDK_HOME to point to it.
  • Alternately use sdkmanager or Android Studio: https://developer.android.com/studio/projects/install-ndk
• You may need to install libtinfo for clang
  • sudo apt-get install libtinfo5

Ink can be built and tested from the repo root:

bazel test --config=linux ink/...

Ink consists of a set of modules that can be used separately. You should only need to include the parts of the library that you need.

 ┌──────────┐ ┌───────┐
 │Rendering │ │Storage│
 └────┬─────┘ └──┬────┘
      │          │
      ▼          │
   ┌───────┐     │
   │Strokes│◄────┘
   └─┬────┬┘
     │    │
     │    ▼
     │ ┌────────┐
     │ │Geometry│
     │ └───┬────┘
     │     │
     ▼     ▼
 ┌─────┐ ┌─────┐
 │Color│ │Types│
 └─────┘ └─────┘

• color: color spaces, encoding, and format conversion.
• types: utility types; time, units, constants, small arrays.
• geometry: geometric types (point, segment, triangle, rect, quad), meshes, transforms, utility functions, and algorithms (intersection, envelope).
• strokes: the primary Stroke data type and InProgressStroke builder.
• rendering: rendering utilities for strokes. Currently only has support for android.graphics.Mesh based rendering.
• storage: Protobuf serialization utilities for Stroke and related types.

See CONTRIBUTING.md for details on sending a PR.

Use GitHub Issues to file feedback: https://github.com/google/ink/issues