LightCraft for Android (arm64-v8a)

An unofficial Android port of LightCraft — the real engine and egui interface, packaged as a NativeActivity APK for sideloading on arm64 devices.

Upstream project	storytold/lightcraft — Apache-2.0 OR MIT
Pinned commit	76b537786 (upstream version 0.6.0)
Android package	ai.storyteller.lightcraft
Published APK	lightcraft-0.6.0-arm64-v8a.apk — 21.3 MB, arm64-v8a, signed
APK sha256	90199f68dff6c0344356a410161eb40e852a913ecc028ce825ee3bb177fffb7f
Upstream files changed	7
New port crate	apps/lightcraft-android/ — about 1 400 lines of Rust plus resources

What this repository is

This is not a fork of LightCraft. It holds only the Android layer, so it stays small, readable, and obviously separable from upstream:

apps/lightcraft-android/   the new shell crate — copy it into your checkout of upstream
patches/                   the diff against upstream — apply it after checking out the pin
docs/PORT-NOTES.md         what was changed and why, fix by fix, with how each one was checked
scripts/                   cross-compile environment, build and verify scripts (from shared-android-port)
CHANGELOG.md               what is in the published APK

The Android layer is not a reimplementation. It is a shell crate that fills the same Services struct the desktop binary fills, so the real engine, the real RAW/HEIC decoders and the real egui UI run unchanged.

Build it

Prerequisites: Rust (rustup) with the aarch64-linux-android target, Android SDK + NDK r27, a JDK 21, and cargo install cargo-apk.

git clone https://github.com/storytold/lightcraft.git
cd lightcraft
git fetch --depth 1 origin 76b5377868d912db69a777bda253a5b1b96b22bd
git checkout FETCH_HEAD                        # the exact commit this port targets
git apply /path/to/0001-lightcraft-android-port.patch
cp -r /path/to/lightcraft-android apps/        # the shell crate from this repository

# any keystore of your own signs an installable APK; a throwaway test key is fine for sideloading
keytool -genkeypair -keystore ks.jks -alias lightcraft -keyalg RSA -keysize 2048 -validity 10000 \
        -storepass android -keypass android -dname "CN=Local Test, O=Local, C=US"
export CARGO_APK_RELEASE_KEYSTORE="$PWD/ks.jks" CARGO_APK_RELEASE_KEYSTORE_PASSWORD=android
cargo apk build --release -p lightcraft-android

scripts/android-env.sh is the cross-compile environment this port was built with (the NDK linker and the C compiler the native dependencies need, and the x86_64 linker for an emulator build), scripts/build-apk.sh wraps the build, and scripts/verify-apk.sh checks the artifact: aapt2 dump badging, apksigner verify, and llvm-nm on the .so inside the APK.

Install

adb install -r lightcraft-0.6.0-arm64-v8a.apk

or copy the APK to the device and open it (installing from unknown sources must be allowed).

On first run, grant Settings ▸ Apps ▸ LightCraft ▸ Special access ▸ All files access if you want the in-app picker to reach photos outside the app's own folders. Without it, Android 10+ refuses a read_dir of shared storage by path, and the picker says so on those roots — naming the permission and the Settings path — rather than showing them as empty.

Verification status

Claim	How it was checked
Installs and launches	adb install -r, then the app's own log (/data/data/ai.storyteller.lightcraft/files/lightcraft.log) starts with LightCraft 0.6.0 starting on Android
The library opens and photos render	the log reports library …: 24 photos; a screen grab shows the Develop view with a decoded, rendered photograph, its histogram, ISO 100 · 18mm · f/2.8 · 1/250, and the full edit panel (Light, Curve, Color, Effects)
The file picker works, end to end	File ▸ Import from Folder… → the picker above the editor. Download first reported that shared storage needs "All files access" and named the Settings path; after granting it and tapping Refresh the folder showed (2 files), Choose this folder handed the path back to LightCraft, whose own Import Photos dialog found and selected the pushed test-photo.jpg (and correctly ignored a .wav). After Import 1 Photo the photo was in the filmstrip and rendering.
File ▸ Quit ends the process	the log ends with File > Quit: ending the process, pidof is empty, the task is gone from dumpsys activity activities, and the app relaunches cleanly
Preferences survive	files/.config/lightcraft/ui.json (the docking layout and settings) is written while the app runs, atomically, and the log holds no write failures after the fix described in docs/PORT-NOTES.md
HEIC decoding works	heif is a default feature of the port crate, and it is proven by decoding: lightcraft-cli render on libheif's genuine example.heic (718 114 bytes, ftyp magic) wrote a real 419 907-byte 512×342 PNG of a photograph. The HEVC decoder is statically linked into the shipped arm64 .so (lightcraft_heif…ycc8_to_rgb, heic_rs…hevc…Frame symbols in the APK)
The artifact is what it claims	aapt2 dump badging → package ai.storyteller.lightcraft, versionName 0.6.0, minSdk 26, targetSdk 35, native-code: 'arm64-v8a'; apksigner verify --verbose → v2 and v3 true; llvm-nm --dynamic --defined-only on the .so inside the APK → android_main and ANativeActivity_onCreate; the injected android.app.lib_name is lightcraft, matching liblightcraft.so; configChanges=0x40001ff8; the theme resolves to attr/windowFullscreen; the quit and picker strings are grep -a'd out of that .so

Not verified: the port's modifier-key tracking was not exercised in the emulator (adb cannot deliver a held modifier), and the picker's touch targets and scrolling are only real on a tablet. Engine GPU compute is used only when the saved preference asks for it; the emulator has no GPU, so the CPU pipeline ran there. Anything about a specific phone's driver is not something an emulator can answer.

Known gaps

• No Android picker sheet. The Storage Access Framework needs startActivityForResult, which android-activity 0.6 does not expose, so dialogs are drawn with egui.
• A few dialog-internal Choose… buttons are hidden rather than shown dead (their synchronous slots are None, which is how the app hides such a command): the display-profile chooser, the watermark graphic in the Export dialog, the AI model installers, the sidebar's Browse Folder…, and the Auto-Import / Smart-Previews folder pickers.
• The SAM 3 mask and denoise features are off: each pulls a large ML stack that is not exercised on Android. Catalog, RAW/standard decodes, the develop pipeline and every export format are in; the AI panels degrade to "not included in this build".
• No system clipboard, no Open With / Show in File Manager, no open-URL (arboard and open have no Android backend), so those services stay None.
• The library, settings and log live in the app sandbox (HOME is pointed at it), because Android sets neither HOME nor USERPROFILE — without that the app opened onto "There is no home folder to keep the library in". A fresh install seeds the library with the demo photos.

The rest of this set

• DeckCraft
• EffectCraft
• FilmCraft
• GridCraft
• PdfCraft
• PhotoCraft
• SoundCraft
• VectorCraft
• WordCraft
• shared-android-port — the pieces every port shares

Credits and licence

LightCraft is © its authors at storytold/lightcraft and is dual-licensed Apache-2.0 / MIT; both licence texts are kept here. The Android layer in this repository is an unofficial modification by @kanaaka, carrying the same licence. Not affiliated with or endorsed by the upstream project. See ATTRIBUTION.md.