Neon on black. Pick up an Apple Pencil, draw, and watch the line light up.
- Draws light. Real neon, not a glow filter: a white hot core inside a saturated halo. 4 styles, 8 gradient inks, and every line shifts colour as it travels.
- Gets out of the way. Pure black canvas, one small toolbar that fades while you draw.
- Lets you rest your hand. Once it has seen a Pencil, your palm is ignored.
- Comes alive. Fireflies drift past your lines, sparks glint off them, a current runs through the tube. Or switch it off and let it sit still.
- Plays itself back. Press play and the drawing redraws itself, at 0.1x to 3x, slowly enough for a kid to follow.
- Saves it. Play mode is where a finished piece goes out: MP4 of the replay, PNG at full resolution, or straight into the share sheet.
git clone https://github.com/bunlongheng/drawing.git
cd drawing
npm install
npm run devOpen http://localhost:3049. For an iPad on the same network, npm run dev -- -H 0.0.0.0 and browse to your machine's address, then Add to Home Screen for a fullscreen pad.
No environment variables, no accounts, no database. Nothing you draw leaves your device.
| Draw | Pencil, finger or mouse |
| Undo, redo | Cmd+Z, Cmd+Shift+Z |
| Save a PNG | Cmd+S |
| Clear | Tap the bin twice |
| Replay | Play, which opens play mode |
| Record, save, share | In play mode: the camera, the arrow, the box |
Zero runtime dependencies beyond Next and React. The glow is additive bloom on a small canvas engine that keeps React out of the hot path, which is how it keeps up with a Pencil at 120Hz.
npm run test:all # 70 unit tests, 34 end to end on Chromium and WebKitMIT (c) 2026 Bunlong Heng