inkit

A simple, fast note-taking app for Android with an eye toward bullet journaling. inkit is designed to be used with Bigme e-ink devices and built on top of inksdk for low-latency stylus input.

Special thanks to imedwei/inksdk for the underlying low-latency ink library that makes this possible.

Philosophy

inkit aims to stay out of your way:

• Simple — pen, eraser, page nav. Nothing else to learn.
• Fast — low-latency stylus input via inksdk's vendor-specific ink controllers.
• Bullet-journal friendly — quick page creation and navigation for daily logs, collections, and rapid logging.
• E-ink first — designed and tuned for Bigme devices, with fallback support for other Android tablets.

Features

• Pen / finger differentiation — uses MotionEvent.getToolType() to distinguish stylus from finger.
• Toggle finger touch — disable finger drawing while pen input remains active, so you can rest your hand on the screen.
• Low-latency ink — leverages vendor-specific ink controllers for pen input.
• Touch-through buttons — control buttons remain tappable even when finger touch is disabled on the canvas.
• Multi-page canvas — flip between pages for journaling-style workflows.

Screenshots

Building

Prerequisites

1. Android SDK (API level 34 or higher)
2. Java 17+ (JDK)
3. Set ANDROID_HOME environment variable pointing to your SDK

Setup

git clone <repo-url>
cd inkit

export ANDROID_HOME=/path/to/android-sdk

./gradlew assembleDebug

The APK will be at: app/build/outputs/apk/debug/app-debug.apk

Usage

1. Draw with stylus — always works (pen input bypasses the finger touch toggle).
2. Draw with finger — works when touch is enabled.
3. Toggle button — enables/disables finger touch on the canvas.
4. Pen / eraser / clear — switch tools or wipe the current page.
5. Prev / next / new — navigate or add pages.

Project Structure

app/
├── src/main/java/com/merrythieves/inkit/
│   ├── MainActivity.kt      # Activity with toolbar and page controls
│   ├── InkSurfaceView.kt    # Custom SurfaceView with pen/finger differentiation
│   ├── CanvasStore.kt       # Page persistence
│   └── InkitApp.kt          # Application class
├── src/main/res/layout/activity_main.xml
└── build.gradle.kts
inksdk/                       # Embedded inksdk library (https://github.com/imedwei/inksdk)
└── src/main/java/com/inksdk/ink/
    ├── InkController.kt     # Interface for ink controllers
    ├── BigmeInkController.kt
    ├── OnyxInkController.kt
    └── NoopInkController.kt

How it Works

Input Differentiation

private fun isPenInput(event: MotionEvent): Boolean {
    val toolType = event.getToolType(0)
    return toolType == MotionEvent.TOOL_TYPE_STYLUS ||
           toolType == MotionEvent.TOOL_TYPE_ERASER
}

private fun isFingerInput(event: MotionEvent): Boolean {
    val toolType = event.getToolType(0)
    return toolType == MotionEvent.TOOL_TYPE_FINGER ||
           toolType == MotionEvent.TOOL_TYPE_MOUSE
}

Touch Event Handling

1. Pen input — always handled (bypasses the touchEnabled flag).
2. Finger input — only handled if touchEnabled = true.
3. When finger touch is disabled, onTouchEvent returns false, allowing events to bubble up to parent views (buttons can still be clicked).

Architecture Notes

• Uses the InkController interface for vendor abstraction.
• Supports Bigme (via HandwrittenClient), Onyx (via TouchHelper), and a fallback (standard MotionEvent path).
• Ink is mirrored to a bitmap for compatibility with system UI composes.
• Onyx TouchHelper owns the surface during raw drawing; Bigme paints to a separate ION buffer.

Acknowledgements

Huge thanks to @imedwei and the inksdk project — inkit would not exist without it.

License

Apache 2.0 (same as inksdk)