lightcraft/README.md

Your photos. Your pixels. Your machine.

Photo library and raw development; an open-source, clean-room reimplementation of Adobe Lightroom, rebuilt in pure Rust.
Native on macOS, Windows and Linux. In the browser via WebAssembly. Drivable end to end by AI agents over MCP.

Note

The product name, binary names, settings folder and environment-variable prefix are set in one place, brand.toml. This README calls the product "the app"; <app>, <binary>, <cli>, <mcp_server> and <settings_dir> stand for display_name, binary, cli_binary, mcp_server and settings_dir, and <PREFIX> for env_prefix, from that file.

Editing · Color grading · Before & after · Masking · Presets · Library · Agents & MCP · Performance · Status · Quick start · Roadmap · Downloads

Edit like you mean it

The app is a complete darkroom in a single native app. Every adjustment is non-destructive, so your originals are never touched. Every slider renders through a scene-referred, wide-gamut, 32-bit float pipeline: highlights roll off like film, shadows open up without halos, and colour stays clean from capture to export.

☀️ Light Exposure, Contrast, Highlights, Shadows, Whites, Blacks, with edge-aware local tone mapping (a guided filter on log-luminance). Pulling −100 Highlights recovers a blown sky without the grey halos you'd get from a naive curve. 🎨 Color White balance by temperature and tint (Kelvin for raw, relative for JPEG) with presets, Auto and a click-to-neutralise eyedropper. Vibrance that protects skin tones, Saturation, an 8-band Color Mixer (hue / saturation / luminance) and 3-way Color Grading wheels with blending and balance. All of it is computed in OkLCh, a modern perceptual colour space.

✨ Effects Texture for fine detail, Clarity for mid-tone punch, Dehaze (dark-channel prior with guided refinement; push it negative to add atmosphere), post-crop Vignette with highlight priority, roundness and feather, and resolution-independent film Grain with size and roughness. 📈 Tone Curve Parametric region curve with movable splits plus point curves for RGB, Red, Green and Blue. Curves are monotone by construction, so you never get an accidental tone inversion.

_{A gentle S on the RGB point curve, right under the Light sliders. Ansel Adams, 1942 (public domain).}

Color grading, the cinematic way

Split-tone shadows, midtones and highlights independently with drag-anywhere colour wheels. Below, Dorothea Lange's Migrant Mother gets a warm, print-like tone (highlights at 42°, shadows at 28°) in two drags.

_{Shadows, midtones and highlights wheels in the Color panel. Dorothea Lange, "Migrant Mother" (1936). Public domain, Library of Congress.}

Before & after

Hold \ to peek at the original, press Y for side by side, or Shift+Y for a split view. Every image below is a real screenshot of the app, captured automatically by an agent through the control channel.

The Tetons and the Snake River. Highlights −45, Shadows +38, Clarity +28, Dehaze +18. Ansel Adams, 1942 (public domain).	Migrant Mother. Shadows +42, Texture +18, split-toned grade, vignette. Dorothea Lange, 1936 (public domain).
Earthrise. Dehaze +22, Highlights −30, warmer white balance, Vibrance +22. NASA / Bill Anders, Apollo 8, 1968 (public domain).	The Blue Marble. Highlights −38, Blacks −20, Dehaze +15, Vibrance +30. NASA, Apollo 17, 1972 (public domain).

Masking that goes where you point

Paint with a Brush (size, feather, flow, density, erase), drop Linear and Radial Gradients with draggable pins, or select by Luminance Range, Color Range, Sky, Subject and Background. Combine components with Add / Subtract / Intersect, invert any of them, and dial in 15 local adjustments per mask (Temp, Tint, Exposure, Contrast, Highlights, Shadows, Whites, Blacks, Texture, Clarity, Dehaze, Hue, Saturation, Sharpness, Noise) plus an overall Amount.

_{A radial "Sun glow" mask (Temp +40, Exposure +0.50) layered over a linear "Sky" mask. Photo from the app's procedurally generated demo library.}

Presets, profiles & the Color Mixer

Eighteen hand-built presets ship in the box (Golden Hour, Teal & Orange, Faded Matte, Selenium Tone, Crisp Landscape and more), each with an Amount slider from 0 to 200 %. Save your own from any group of settings, mark favourites, and copy, paste or sync edits across a whole selection with exactly the groups you choose.

_{The Presets column next to the 8-band Color Mixer. Photo from the demo library.}

✂️ Crop, straighten & geometry Free or locked aspect ratios (1:1, 4:5, 5:7, 2:3, 4:3, 16:9, 16:10, original), drag-to-rotate straightening that always keeps the largest crop inside the image, thirds / grid / golden-ratio overlays, flips and 90° rotations, plus manual Vertical, Horizontal, Rotate, Aspect, Scale and Offset transforms.	⚫️ Black & White One click (V) to monochrome, with an 8-band B&W Mix that lets you darken skies or make foliage glow. Then tone it with Color Grading for selenium, sepia or split-tone prints.
A 16:9 crop straightened +2.5° with the thirds overlay. Ansel Adams, 1942 (public domain).	Split view: colour original on the left, B&W with Clarity, Vignette and Grain on the right. Demo library.

Organize everything

A library that stays out of your way: All Photos, Recently Added, Picks, By Date, Albums nested in Folders, and Recently Deleted. Rate with 0–5, flag with P / X / U, colour-label with 6–9. Search understands fields: rating:>3 flag:pick iso:>800 camera:x2 date:2026-04 keyword:mountains. Every view sorts by capture date, import date, edit date, name, rating, size or at random (a stable shuffle; View → Sort → Reshuffle for a new one). The justified Photo Grid and Square Grid views are virtualized, so they stay smooth whether you have forty photos or forty thousand.

Photo Grid with albums nested in a folder, ratings and flags. Demo library.	Square Grid of the four public-domain showcase photos.
The Info panel: file, dimensions, rating, title, caption, copyright and camera metadata. NASA / Bill Anders, "Earthrise", Apollo 8, 1968 (public domain).

Built for agents

Every menu item, slider, brush stroke, crop handle and keystroke in the app is a command with a stable id and JSON parameters. The UI, the keyboard, the CLI, a JSON-lines control channel and an MCP server all dispatch through the same entry point. An agent can cull a shoot, develop it, mask a sky and export it, and see the result.

<binary> --control 7980 ~/Pictures/trip

{"method": "engine.execute", "params": {"command": "photo.flag",  "params": {"flag": "pick"}}}
{"method": "engine.execute", "params": {"command": "develop.set", "params": {"values": {"light.highlights": -45, "light.shadows": 38}}}}
{"method": "engine.execute", "params": {"command": "mask.add",    "params": {"kind": "radial", "center": [0.62, 0.4], "rx": 0.2, "ry": 0.14}}}
{"method": "ui.clickWidget",   "params": {"id": "slider:effects.clarity"}}       // drive any widget by name
{"method": "ui.pointer",       "params": {"events": [{"kind":"down","x":0.2,"y":0.3}, {"kind":"up","x":0.4,"y":0.3}]}}
{"method": "ui.screenshot",    "params": {"path": "after.png"}}

• Command registry. engine.commands lists the available commands; develop.controls lists every slider's range, default and current value.

• MCP server. <cli> mcp exposes the command registry to Claude (or any MCP client), alongside helpers for import, query, develop, mask, render (returned as an image) and export. It runs headless, or attached to the running app with screenshots, clicks and gestures. See docs/mcp.md.

  cargo build --release -p dac-cli
  claude mcp add <mcp_server> -- "$PWD/target/release/app-cli" mcp ~/Pictures/shoot          # headless
  claude mcp add <mcp_server>-app -- "$PWD/target/release/app-cli" mcp --connect 127.0.0.1:7980  # live app
  

• Scriptable CLI: <cli> run --import in.dng develop.set control=light.exposure value=0.7 app.export path=out.jpg longEdge=2048 runs any chain of commands (headless, on a saved library, or against the running app) and prints one JSON result per command; <cli> render in.dng -o out.jpg --set light.exposure=0.7 --preset ….

• Undo for everything, including agent actions: a slider drag (or a scripted burst of updates) is one undo step.

• Every widget is addressable (ui.widgets) and clickable by name, so agents operate the real UI, not a side door.

• The screenshots in this README were produced end to end by the docs/showcase/ scripts. Protocol reference: docs/control-protocol.md.

Fast, native, private

• Pure Rust, no C. Our own RAW decoders (DNG, Canon CR2/CR3, Sony ARW, Nikon NEF, Fujifilm RAF incl. X-Trans, Panasonic RW2 / Leica RWL, Pentax PEF, Olympus ORF), our own colour science, our own pipeline. JPEG, PNG, TIFF, WebP, PSD composites and JPEG XL open today; HEIC/HEIF photos too with --features heif (HEVC is a build-time choice, as in PhotoCraft).
• Scene-referred & wide-gamut. Linear Rec.2020 float internally, Bradford-adapted white balance, gamut mapping instead of clipping, a filmic shoulder for raw and pixel-exact pass-through for JPEGs you haven't touched.
• Resolution-independent edits. Radii and brush sizes are relative to the image, so a 400 px preview, your 5K display and a 60 MP export look the same.
• GPU-accelerated, CPU-exact. The whole develop pipeline runs as wgpu compute kernels (Metal / Vulkan / DX12), checked against the CPU pipeline to within 1/255. On a 24 MP raw (Apple M4 Pro): a slider update re-renders in ~4 ms, a cold 2.5 MP loupe in ~30 ms, and a full-size export in ~0.3 s including a parallel JPEG encode. Without a GPU the same pipeline runs on all CPU cores, redoing only the stages a slider affects.
• Instant culling. Opening a raw shows its embedded camera preview or cached render within ~0.1 s while the full render follows (~0.2–0.5 s for 24 MP). The next and previous photos are prepared in the background, so stepping through a shoot takes ~50 ms per photo.
• Background rendering. A worker pool renders the loupe, before/after and every visible thumbnail off the UI thread: drafts during drags, full quality on release.
• Local-first. No account, no cloud, no telemetry, no subscription. Your catalog is an append-only log of human-readable operations you can diff, back up or replay.

Feature status

The app is young and moving fast. Where we honestly stand (details in the roadmap):

• By feature count we're at ~79% of Lightroom (core features 98%), tracked row by row in docs/parity.md.
• As a day-to-day Lightroom replacement we're nearer 60–70%. It's great for JPEG/DNG and most Nikon / Sony / older-Canon raws on one machine.
• The biggest gaps:
  • camera colour calibration: Sony, Nikon, Panasonic, Fujifilm and Canon CR3 raws have guarded estimates from their camera JPEGs, with built-in ILCE-7M4, X-H2S and X-T4 profiles; measured calibration is missing, and other raws or rejected fits retain a neutral matrix;
  • compressed Olympus raws and unsupported CR3 variants: these use embedded JPEG previews when present. Fujifilm lossless/lossy compressed RAF now decodes sensor data; verification and existing-library reload instructions;
  • AI masks and denoise: subject and sky selection are classical heuristics;
  • HDR, video and the Classic Print / Book / Map modules.
• What's next: see where we're going.

Area	Status
Library: albums, folders, smart albums, stacks (incl. auto-stack), virtual copies, ratings, flags, labels, filter bar, search, sort, grids, filmstrip	✅
Culling: Compare (synced zoom) and Survey views, auto-advance, instant previews	✅
Light, Color, Effects (vignette styles), Tone Curve (+ refine saturation, targeted adjustment), Color Mixer (+ targeted), Point Color, Color Grading, Calibration, B&W	✅
Masking: brush, linear, radial, luminance/colour range, add/subtract/intersect	✅ (AI subject/sky use classical heuristics for now)
Crop, straighten tool + auto straighten, flip, rotate, aspect ratios, overlays	✅
Profiles (Color, Neutral, Vivid, Landscape, Portrait, Monochrome: our own looks), presets, versions, history, copy/paste/sync settings	✅
Camera colour: DNG files use their own matrices	✅ DNG · 🟡 own Sony/Fujifilm profiles; measured calibration database missing
Native macOS menu bar (generated from the command registry), control channel + every widget addressable, headless UI snapshots	✅
RAW: DNG, CR2, CR3 (lossless CRX Bayer and version 0x100/0x200 C-RAW), ARW, NEF (uncompressed + lossless/lossy compressed), Fujifilm RAF (uncompressed + lossless/lossy compressed, Bayer + X-Trans), Panasonic RW2 / Leica RWL / Panasonic RAW (every raw format, DMC-LX1 to DC-S1RM2), Pentax PEF, Olympus ORF (uncompressed), Samsung SRW (uncompressed); embedded previews for every format incl. CR3	🟡 · CR3, compressed ORF and compressed SRW decode ⬜
Detail: sharpening, luminance + colour noise reduction	✅ · AI Denoise, Super Resolution ⬜
Remove / Heal / Clone spots (auto source), Visualize Spots, Red Eye and Pet Eye (auto pupil detection, catchlight)	✅ · content-aware fill, spot pin editing 🚧
Export: JPEG / PNG / TIFF / WebP / AVIF / DNG / original, sizing, file-size limit, output sharpening, naming templates, batch, metadata policy, text or image watermark	✅ · HDR export ⬜
Library persistence (crash-safe op log + snapshots, background compaction, failed saves reported), disk thumbnail cache	✅
Import: Add in place / Copy / Move, rename and folder templates, devices, duplicate detection, watched folders; Local folder browsing	✅
MCP server (headless or live app, persistent libraries), CLI, control channel	✅
XMP sidecars (read/write, auto-write), reading crs: develop settings, preset files (.lcpreset, XMP presets)	✅
Optics (distortion, vignetting, auto + manual CA, defringe, lens corrections embedded in DNG files and Panasonic / Leica RW2 / RWL distortion data), Geometry (transforms, Constrain Crop), Upright (Auto/Level/Vertical/Full/Guided)	✅ · camera lens profiles (our own) ⬜
Photo Merge: HDR (auto-align, deghost), Panorama (spherical/cylindrical/perspective, boundary warp, auto crop), HDR Panorama → DNG	✅
GPU pipeline (wgpu compute, CPU-exact within 1/255), CPU fallback on device limits / errors	✅ · WebGPU in the browser 🚧
AI: segmentation masks, AI denoise, super resolution, faces; HDR editing; video	⬜ (see roadmap)
Web build (same UI in the browser via WASM): persistent library in OPFS/IndexedDB, Web Worker rendering, export downloads	✅ · WebGPU, Safari/Firefox testing 🚧

_{✅ works today · 🚧 in progress · ⬜ not started}

Quick start

git clone https://example.invalid/repo && cd repo
cargo xtask brand check                                 # the product name lives only in brand.toml
cargo xtask run                                         # build and open your library (~/Pictures/<app> Library; a new one starts with demo photos)
cargo xtask run -- ~/Pictures/trip                      # import your photos (folders are scanned, duplicates skipped)
cargo xtask run -- --memory                             # a throwaway in-memory demo session (writes nothing)
cargo xtask run -- --control 7980                       # with the automation channel
cargo xtask web --serve                                 # the same app in the browser: http://127.0.0.1:8080/
cargo run --release -p dac-cli -- render photo.jpg -o out.jpg --set light.exposure=0.5
cargo xtask package                                     # installers and archives under the brand binary names
cargo xtask install                                     # install the app and CLI for the current user
cargo xtask ci                                          # fmt, clippy, tests, layering, wasm checks

Inside target/ the binaries are always called app and app-cli; cargo xtask run, package and install give them the brand names from brand.toml. cargo run -p dac-app / -p dac-cli also work for development.

CI defaults to line-table debug information and one build job per 1.5 GB of RAM available when it starts (at most one per CPU; 4 if memory can't be read), so an 8 GB machine with 6 GB free builds with 4, and a busy machine with little free builds with fewer. Test threads follow, capped at 4. Full-debuginfo linkers, one per CPU, otherwise exhaust RAM before any test runs. GPU coverage is unchanged. Explicit CARGO_PROFILE_DEV_DEBUG, CARGO_BUILD_JOBS and RUST_TEST_THREADS settings override these defaults. Ordinary development commands keep their own settings.

Chinese and Japanese text need the shared font repo, an optional build input (official releases always include it):

git clone https://github.com/storytold/craft-fonts ../craft-fonts
CRAFT_FONTS_DIR=../craft-fonts cargo run --release -p dac-app

Without it the app builds and runs the same, but Chinese and Japanese text have no glyphs. Fonts are never committed to this repo; see craftrules standards/fonts.md.

Interface language: Edit → Language (English, 简体中文, 繁體中文（台灣）, 日本語, Português (Brasil), Deutsch) or Settings → General → Language; the choice applies immediately and persists. See docs/localization.md.

Logs: the desktop app writes its log to standard error and to logs/<binary>.log in its settings folder (Linux $XDG_CONFIG_HOME/<settings_dir>/logs/, by default ~/.config/<settings_dir>/logs/; macOS ~/Library/Application Support/<settings_dir>/logs/; Windows %APPDATA%\<settings_dir>\logs\), never in the library. A launch from a desktop menu or the Dock has no terminal, so attach this file to a bug report (Help ▸ Open Log Folder shows it in the file manager). Each start moves the previous log to <binary>.1.log and that one to <binary>.2.log, so the log of a run that crashed survives the next start; the file stops growing at 16 MiB, --version and --help write none, and runs with <PREFIX>_NO_PREFS log to standard error only. By default the app's own crates log at info and everything else at warn. <PREFIX>_LOG=info or debug works as before (that level for the app's own crates, warnings and errors from the rest; any other value: warnings and errors only) and wins over RUST_LOG, which otherwise replaces the default with env_logger-style directives such as RUST_LOG=debug or RUST_LOG=warn,dac_pipeline=trace (a directive ending in * covers every target starting with it, as in dac*=debug). Panics are recorded there too, and still in <binary>-panics.log in the temp folder. The logger is apps/app/src/logging.rs.

The web build needs the wasm32-unknown-unknown target and the matching wasm-bindgen CLI (cargo xtask web prints the exact install command); see docs/web.md.

Nix builds the desktop app and <cli> (the Nix build always includes the craft-fonts input, so Japanese text has glyphs):

nix run <flake-url>                    # the desktop app
nix build <flake-url>                  # → ./result/bin/{<binary>,<cli>}
nix develop <flake-url>                # rust toolchain + native deps + fonts

In a flake configuration (NixOS, home-manager, nix-darwin):

# flake.nix
inputs.app.url = "<flake-url>";
# optional: build against your own nixpkgs instead of the one the app pins
# inputs.app.inputs.nixpkgs.follows = "nixpkgs";

# then, in a NixOS or home-manager module (where `inputs` is in scope):
nixpkgs.overlays = [ inputs.app.overlays.default ];   # makes `pkgs.<binary>` available
environment.systemPackages = [ pkgs.<binary> ];           # home-manager: home.packages = [ pkgs.<binary> ];

nix build installs the same desktop file, hicolor icons and AppStream metadata as the .deb/.rpm, and runs cargo test --workspace as its check phase (skip it with pkgs.<binary>.overrideAttrs { doCheck = false; }).

Keyboard: G grid · D detail · E edit · C crop · M masking · Shift+P presets · \ original · Y before/after · Z zoom · J clipping · ⌘Z undo · ⌘/ all shortcuts.

How it's built

An engine-first Cargo workspace of small, tested crates with enforced layering (cargo xtask layers): geom, color, raster, tiff → raw, codecs, meta, develop → pipeline → catalog → engine → ui-egui. The egui frontend is one swappable crate; nothing below it knows a UI exists. mcp and the apps (app, <cli>) sit on top of engine.

Contributing

Humans and agents follow the same rules, so read AGENTS.md first. The short version:

• Clean-room. Never read Adobe binaries or GPL raw/photo code (darktable, RawTherapee, LibRaw, rawspeed, dcraw…); work from public specs and black-box observation.
• No Adobe assets, ever: no icons, screenshots, presets, profiles, LUTs or fonts from Adobe products. Every image, icon and font in the repo is original, public domain, Creative Commons, OFL or permissively licensed, and has an entry in assets/ATTRIBUTION.md added in the same commit. New fonts go to storytold/craft-fonts, not here.
• Pure Rust, enforced crate layering, everything is a command, and cargo xtask ci green before every commit (one task id per commit).
• Never crash. Non-test code returns errors instead of panicking: no unwrap(), expect(), panic! or unsafe, checked indexing on anything derived from input, and a regression test with every crash fix. Details in AGENTS.md.

Downloads

Release builds are listed on the project's releases page. <ver> in the file names is the version number, <binary>/<cli> are the brand binary names, and SHA256SUMS.txt lists a checksum for every file. Build them yourself with cargo xtask package.

Windows

Build	Installer	Portable
x64 (64-bit Intel/AMD)	<binary>-<ver>-windows-x64.msi	<binary>-<ver>-windows-x64-portable.zip
arm64 (Snapdragon and other ARM PCs)	<binary>-<ver>-windows-arm64.msi	<binary>-<ver>-windows-arm64-portable.zip
x86 (32-bit)	<binary>-<ver>-windows-x86.msi	<binary>-<ver>-windows-x86-portable.zip

Installers and executables are code-signed.

macOS

Build	File	Notes
App, universal (Apple silicon + Intel)	<binary>-<ver>-macos-universal.dmg	Signed and notarized
Command-line tool, universal	<cli>-<ver>-macos-universal.zip	Signed and notarized

Linux

Format	x86_64	aarch64 (ARM64)	Notes
AppImage	<binary>-<ver>-linux-x86_64.AppImage	<binary>-<ver>-linux-aarch64.AppImage	Runs anywhere; updates itself with AppImageUpdate (.zsync files)
Flatpak	<binary>-<ver>-linux-x86_64.flatpak	<binary>-<ver>-linux-aarch64.flatpak	Sandboxed; flatpak install --user <file>
Debian/Ubuntu	<binary>-<ver>-linux-x86_64.deb	<binary>-<ver>-linux-aarch64.deb
Fedora/RHEL/openSUSE	<binary>-<ver>-linux-x86_64.rpm	<binary>-<ver>-linux-aarch64.rpm
Tarball	<binary>-<ver>-linux-x86_64.tar.gz	<binary>-<ver>-linux-aarch64.tar.gz	Unpack anywhere

FreeBSD

Build	File
x86_64	<binary>-<ver>-freebsd-x86_64.tar.gz

Web (WebAssembly)

Build	File	Notes
Static site	<binary>-web-<ver>.zip	Runs in a modern browser; host it on any static server

License and credits

The app is licensed under the MIT License, except crates/segment and crates/fetch, which are Apache-2.0 only. It is a fork of an upstream open-source project; the upstream copyright notices and required third-party notices are in LICENSE and NOTICE.

Bundled fonts, icons, images and other assets keep their own open licenses; each one is listed with its author, source and license in assets/ATTRIBUTION.md.

Showcase photographs are public-domain works, used via Wikimedia Commons: Ansel Adams, The Tetons and the Snake River (1942, U.S. National Archives); Dorothea Lange, Migrant Mother (1936, Library of Congress); Bill Anders / NASA, Earthrise (1968); NASA, The Blue Marble (1972). The demo library is procedurally generated by the app. UI font: Inter (SIL OFL 1.1). Builds made with craft-fonts (all official releases) also embed its Chinese and Japanese fonts (Noto Sans CJK SC, BIZ UDPGothic, BIZ UDMincho, Shippori Mincho; SIL OFL 1.1), listed in its ATTRIBUTION.md. All icons are original.

Forks and modified versions must remove them.

_{Adobe, Photoshop, Illustrator, Premiere Pro, Lightroom, Acrobat, After Effects and InDesign are trademarks or registered trademarks of Adobe Inc. in the United States and/or other countries. The app is an independent, open-source project and is not affiliated with, sponsored by or endorsed by Adobe Inc.; these names are used only to describe the workflows it is compatible with.}