NegSwift

macOS-native app for quick film scan processing — import negatives, adjust crop, tone and color, export. The shipping app links the Swift (native) engine in Packages/NegSwiftEngine (in-process, CPU-first, Metal for selected stages). Python remains the parity oracle for make compare-* and Engine/ pytest — build it with the NegSwift-Python scheme when you need the subprocess path.

Backend	Role	How it runs
Swift (native) — default	Approved in-process port of the NegSwift lite path	Linked into the app; no subprocess
Python (oracle) — dev only	Full NegPy pipeline	Engine/.venv subprocess via NegSwift-Python scheme; not shipped

Both backends speak the same NDJSON protocol. Engine selection is compile-time — see docs/ENGINE_SELECTION.md.

Platform: macOS 14+ only. License: GPL-3.0 (see LICENSE and NOTICE). Camera RAW uses LibRaw (LGPL-2.1 or CDDL-1.0).

What you get

• Import — open a folder of scans; film strip with lazy thumbnails; drag-and-drop
• Process — C-41 and B&W negatives; auto density / auto grade; density, grade, saturation; zone tone (shadows/highlights density and split grade); WB cyan / magenta / yellow
• Geometry — auto crop, rotation, reflection, aspect presets
• Retouch — scratch tool (polyline heal along hairs and scratches)
• Export — JPEG and TIFF (sRGB); single frame or batch (all / multi-select)
• Compatibility — .negpy sidecars and the same WorkspaceConfig as desktop NegPy; edits round-trip

Advanced workflows (scanner capture, dodge/burn, gear library, soft proof, contact sheets, etc.) are not available (use NegPy desktop instead).

Status

Track	Status
M0–M15 (lite shell)	Feature complete — import, controls, crop, export, batch export, scratch tool, zone tone
M12 (performance)	In progress — JPEG preview transport and instant revisit done; manual benches remain
S0–S14 (native engine)	S13 automated done — S13a–m and S14 camera RAW shipped; optional S13l + human rows remain

See PLAN.md for the full roadmap. Contributors and agents: read AGENTS.md first.

make sync                  # init submodule + uv sync (oracle / pytest)
make test                  # native SwiftPM + Swift tests + engine pytest
make test-native-engine    # NegSwiftEngine package only
make bench-engine          # M12: refresh synthetic perf baseline JSON
make compare-engines       # Python vs Swift display MAE (informational)
make build-app             # Swift Debug build (no sync required)
make build-release         # Swift Release .app

Layout

NegSwift/
├── Vendor/NegPy/           # upstream color science (git submodule, pinned SHA)
├── Packages/NegSwiftEngine/ # native Swift engine + negswift-engine-swift CLI
├── App/                    # SwiftUI macOS app (Xcode)
├── Engine/                 # thin Python daemon + CLI (imports negpy)
├── Packaging/              # signing + notarization scripts
└── docs/                   # protocol, performance, batch export, release, manual checklist

Development

Requirements: macOS 14+, Xcode, uv, Python 3.13. Clone with submodules. For Swift camera RAW: brew install libraw (stub builds with NEGSWIFT_LIBRAW=0).

git clone --recurse-submodules https://github.com/gacevedo/NegSwift.git
cd NegSwift
make build-app   # Swift default; run from Xcode (⌘R) with scheme NegSwift
make test        # needs make sync for engine pytest

If you already cloned without submodules:

git submodule update --init --recursive

Swift backend (default): scheme NegSwift — in-process engine, no Python venv for preview/export. Camera RAW needs brew install libraw.

Python oracle: scheme NegSwift-Python or make build-app-python after make sync. Override the subprocess path with the NEGSWIFT_ENGINE env var. The standalone CLI negswift-engine-swift serve --stdio passes protocol tests via make test-s7-stdio.

NegPy contributors can point the Python engine at a sibling checkout via Engine/pyproject.override.toml (see Engine/README.md).

Distribution builds, signing, and notarization: docs/RELEASE.md.

Documentation

Doc	Purpose
PLAN.md	Roadmap and milestones (M0–M16 + S0–S14)
docs/ENGINE_SELECTION.md	Build-time Swift vs Python engine
AGENTS.md	Agent and contributor conventions
docs/ENGINE_PROTOCOL.md	NDJSON IPC between app and engine
docs/BATCH_EXPORT.md	Batch export design
docs/PERFORMANCE.md	M12 benchmarks and native-engine perf gates
docs/MANUAL_TEST_CHECKLIST.md	Per-milestone smoke tests
Vendor/NegPy/docs/PIPELINE.md	Pipeline and color science (upstream)