OpenLumen

    

Open-source spiritual successor to Chainfire's CF.Lumen. Brings root-grade display color shifting and overlay-based fallback to modern Android, with the AOSP ColorDisplayManager path that CF.Lumen never had.

CF.Lumen has been dormant since December 2020. Red Moon, the main open-source overlay-only competitor, has been unmaintained since August 2022. OpenLumen exists to fill that gap on Android 14 / 15 with a clean Compose UI, no telemetry, and four runtime-selectable display drivers.

Why OpenLumen?

• Four display drivers, runtime-detected — uses the highest-quality one the device supports.
• No INTERNET permission, ever. Fully offline, F-Droid-clean.
• Catppuccin Mocha + AMOLED true-black Compose UI. Dark by default.
• Quick Settings tile for one-tap toggling. CF.Lumen never shipped a tile.
• GPL-3.0-or-later, aligned with Red Moon's lineage.
• Modern Android targets — minSdk 26, targetSdk 35 (Android 15).
• Stack: Kotlin · Jetpack Compose · Material 3 · Hilt · DataStore · kotlinx.serialization.

Display drivers

OpenLumen ships four ColorEngine implementations and probes each at first launch:

¹ Some builds require granting WRITE_SECURE_SETTINGS via: adb shell pm grant com.openlumen android.permission.WRITE_SECURE_SETTINGS

The app falls back gracefully — if none of the root paths work, you still get the overlay driver. If you want to pin a specific driver, Settings → Driver lets you.

Features (v0.5.0 — in development)

Color

• Named presets: Night · Amber · Red · Salmon · Sepia · Grayscale · Deep Sleep · Protan · Deutan · Tritan
• Custom R/G/B picker on Home with live color preview
• Kelvin color-temperature slider (1000–10 000 K) with Tanner Helland conversion
• Per-channel gamma sliders (γR / γG / γB, range 0.5–2.5)
• Intensity slider (0–100% lerp toward identity) and dim slider (0–95%)
• Contrast multiplier (0.5–2.0×)
• AMOLED true-black clamp (opt-in; snaps very dim subpixels to fully off)
• Blue-channel reduction indicator (physical measurement; not a sleep claim)

Scheduling

• Solar-position schedule (NOAA algorithm, hand-rolled, no external library)
• Sunset / sunrise offset sliders (±180 minutes)
• Fixed-time schedule with Material 3 24-hour time pickers
• "Until my next alarm" mode driven by the system alarm clock
• Manual location entry with bundled offline city picker (~95 cities, no Play Services)
• No runtime location permission; solar scheduling uses coordinates the user enters
• Ambient-light-sensor trigger (lux below threshold engages filter; OR with schedule)
• Live lux readout + "calibrate: use current reading" button
• Smooth fade-in / fade-out transitions (Instant / 30 s / 5 min / 15 min / 30 min)
• Schedule timezone hint so fixed-time windows are unambiguous after travel

Command surfaces

• Quick Settings tile (subtitle shows active preset; long-press opens the app)
• 1 × 1 toggle widget
• 4 × 1 favorites widget (tap a chip to switch presets)
• Foreground-service notification with Turn-off and Next-preset actions
• Documented Tasker / Termux / ADB intent surface (docs/automation.md)

Persistence + reliability

• Foreground service with specialUse type (Android 14+ compliant)
• AlarmManager-driven schedule transitions (setExactAndAllowWhileIdle, Doze-resilient)
• Boot persistence with crash-window safety net (no auto-restart after a recent crash)
• Profile export / import as JSON via Storage Access Framework, with diff preview
• Named profile library — save current configuration, load it back later
• Previous-preset restore (one-tap undo of a preset change)
• Local-only crash log + structured diagnostics log (filesDir/, viewable in-app)
• Versioned preference schema with explicit migrations

Trust + privacy

• No INTERNET permission, ever (CI rejects builds that contain one)
• No Play Services / Firebase / Google APIs (CI rejects builds that pull them in)
• No accessibility service, no usage-stats permission, no foreground-app detection
• Permission rationale card for SYSTEM_ALERT_WINDOW (overlay driver)
• In-app driver report (Copy or Share) with zero PII — captures device, build, granted permissions, every engine's probe result

Privacy

OpenLumen requests zero network permissions. No telemetry, no crash reporting, no remote config. Verify with:

aapt dump permissions OpenLumen-release.apk | grep INTERNET
# (no output)

Requirements

• Android 8.0 (API 26) or higher
• For best results: root with Magisk-managed su, OR a Pixel / Android-One device whose system Night Light is functional (the AOSP driver piggy-backs on it).

Build

git clone https://github.com/SysAdminDoc/OpenLumen.git
cd OpenLumen
./gradlew assembleRelease

Signed release builds require:

export OPENLUMEN_KEYSTORE=/path/to/release.jks
export OPENLUMEN_KEYSTORE_PASSWORD=...
export OPENLUMEN_KEY_ALIAS=openlumen
export OPENLUMEN_KEY_PASSWORD=...
./gradlew assembleRelease

Module layout

OpenLumen/
├── app/             — Compose UI, foreground service, tile, boot receiver
├── core-engine/     — ColorEngine abstraction + 4 driver impls + DriverProbe
├── core-schedule/   — NOAA solar calculator, schedule modes, light sensor adapter
└── core-prefs/      — DataStore-backed prefs, JSON serialization

Documentation

For users

• Troubleshooting — common driver and overlay problems, recovery from stuck states
• Compatibility table — which engines work on which hardware
• Root mode safety and recovery — what can go wrong with root drivers, and how to recover
• Automation — Tasker / Termux / ADB intent reference
• Health and evidence notes — what we will and will not claim

For contributors

• Architecture overview — modules, runtime flow, engine contract
• Contributing — style, tests, driver-work expectations
• Translations and localization — how to contribute a translation
• Device validation matrix — per-engine smoke flow, current device coverage
• Profile import lineage formats — notes for future Red Moon / CF.Lumen importers

For distributors and packagers

• Release checklist — pre-flight, verification, no-INTERNET assertion
• Reproducible build notes — environment pinning, verification procedure
• Play FGS evidence pack — Play specialUse justification

Security and supply chain

• Threat model — MASVS-lite categories with mitigations
• SBOM and advisory scan — CI workflow and triage policy
• Dependency verification — Gradle metadata procedure (opt-in)
• Wake / alarm / battery audit — what wakes the device and why

Roadmap and design

• Roadmap — source-backed release plan with the candidate inventory
• Overlay safety and per-app design notes — why per-app behavior is deferred until the trust posture is sorted
• Deferred roadmap candidates — design sketches for Wear OS / Android TV / etc.
• Android 17 readiness — forward-looking Android-version migration notes (renamed from api-36-readiness.md in rev 4)
• Research watchlist — sources we monitor before release planning

Emergency off

If a release goes wrong and the overlay or root driver leaves your screen in a bad state, the canonical escape hatch is:

adb shell am startservice -a com.openlumen.action.TURN_OFF \
    -n com.openlumen/.service.LumenService

See docs/root-safety.md for more recovery paths.

Roadmap

See ROADMAP.md for the source-backed release plan and the candidate inventory. The Now: v0.5.0 section is largely shipped; the deferred items have design sketches in docs/deferred-candidates.md and docs/overlay-and-per-app-design.md.

Post-v0.5.0 work clusters around:

• A Shizuku-backed privileged path for per-app behavior (C06)
• Broader screenshot screen coverage beyond the initial Compose Preview / Roborazzi theme-token fixtures (C83)
• Wear OS companion as a separate F-Droid package (C21)
• Real-device validation rows in docs/device-matrix.md (C01)

License

GPL-3.0-or-later. See LICENSE.

Acknowledgements

• Chainfire (Jorrit Jongma) for the original CF.Lumen and for documenting the driver-backend approach so thoroughly that this project could be built without the original source.
• LibreShift/red-moon for proving open-source overlay shifting works on Android.