# Ink App Builder

Adds inking and freehand drawing capabilities to an Android app using Jetpack Ink...

- Repository: https://github.com/android/skills (10219 stars)
- Category: Mobile
- License: Complete terms in LICENSE.txt
- Last updated: 2026-10-29
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add android/skills --skill ink-app-builder -g -a claude-code -y`
Codex: `npx skills add android/skills --skill ink-app-builder -g -a codex -y`
Cursor: `npx skills add android/skills --skill ink-app-builder -g -a cursor -y`
Gemini CLI: `npx skills add android/skills --skill ink-app-builder -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add android/skills`

## Description

Adds inking and freehand drawing capabilities to an Android app using Jetpack Ink (androidx.ink) and Compose. Use this skill when implementing stylus or touch drawing surfaces, rendering wet and dry ink strokes, configuring stock brushes (pressure pen, marker, highlighter), implementing geometry-based erasing, linear undo and redo history, or stroke persistence with Room. Delivers working Compose and ViewModel implementations. Don't use for View-based (XML) inking or programmatic custom BrushFamily creation. For custom BrushFamily creation, custom tip shapes, or behavior node graphs, suggest the ink-custom-brush-builder skill.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

The Android Ink API (`androidx.ink`) is a modular Jetpack library for building
high-performance, low-latency freehand drawing experiences on Android. It uses a
**wet ink and dry ink** two-phase model:

- **Wet ink** : Real-time, ultra-low-latency rendering while the user is drawing, handled by the `InProgressStrokes` composable.
- **Dry ink** : Finalized, immutable `Stroke` objects rendered by the app using `CanvasStrokeRenderer`.

## Setup and dependencies

The Ink API requires **`minSdk = 26`** , which corresponds to Android 8.0 (API
level 26) and higher. All `androidx.ink` modules MUST share an identical version
in `gradle/libs.versions.toml`. Ask user permission before modifying project
build files.

### Version selection (`1.0.0` stable versus `1.1.0-alpha03` and higher)

- Use **`1.0.0` (Stable)** for production apps that rely on `StockBrushes` or pre-serialized `.brush` assets decoded with `BrushFamily.decode`. In `1.0.0` stable, `BrushFamily.encode`, `BrushFamily.decode`, `AndroidBrushFamilySerialization`, and `BrushFamilyDecodeCallback` require `@OptIn(ExperimentalInkCustomBrushApi::class)`.
- Use **`1.1.0-alpha03` and higher** when the app constructs programmatic custom brushes (`BrushFamily`, `BrushCoat`, `BrushTip`, `BrushPaint`, `BrushBehavior`) in Kotlin code. Starting in `1.1.0-alpha02` and higher, `BrushFamily` serialization requires no `@OptIn` (and in `1.1.0-alpha05` and higher, `ExperimentalInkCustomBrushApi` is `@RestrictTo(LIBRARY_GROUP)`, so NEVER annotate `1.1.0-alpha03` and higher code with it).

### Version catalog (`gradle/libs.versions.toml`)

    [versions]
    ink = "<latest_version>"
    inputMotionPrediction = "<latest_version>"

The rest: https://github.com/android/skills/blob/HEAD/jetpack-compose/ink/ink-app-builder/SKILL.md