The four knots were read at the pixel's own luma, which makes the ramp a global curve: every pixel at luma t lands on the same o whatever surrounds it. SHADOW's a1 is the head of the quarter above it, so lifting it squashed that whole quarter to the half slope left over — measured on a real frame, 0.50 of its spread (shadow-band.py), 0.57 on the deployed bundle — the grey sheet the knob was reported for. A curve drawn through the pixel cannot see local contrast; that is what the eye was reading. So the ramp is read at TONE_BASE_RADIUS (2.5% of the frame) of the luma around the pixel — a 3x3 range-weighted blur, the fix_shadow.md Base x Detail split — and the pixel then rides the neighbourhood's gain o/base, keeping its own difference from it. Base moves, detail stays: the same lift on the same pixels, with the texture inside the region left standing. Full deflection keeps 0.78 of the band's spread now. The base is the same maths in every caller: bx = 0 (a mask, which has no neighbourhood) reads the pixel nine times and gets the old global move back, and with every knob on zero the ramp at base IS base, so the ratio is 1 and the pass is the identity however coarse the base is. Skipped: no chroma compensation (Hunt). Measured, the ratio held saturation (0.3184 -> 0.3169), so it is not earned yet. No linear-light ramp either: the multiply is a uniform gain on encoded values, which is the same stop exposureMove already argues for.
RecipesCam
RecipesCam is a camera and photo-editing app built around recipes — reusable
looks that carry a film simulation plus a full set of adjustments. You shoot or
open a photo, dial in a look, and keep it as a recipe you can apply again, share
as a .recipe file, or save to your account.
It ships twice from one repository: a React Native (Expo) app for iOS and
Android, and a self-contained web build under docker/ that runs the same
render pipeline in the browser.
What it does
- Shoot with a recipe applied. Live viewfinder, GPS-tagged captures, and the recipe baked into the saved file.
- Film simulations. Built-in looks — PROVIPES, VELVIPES, CLASSIC CHRIPES, CLASSIC NEGIPES, ASTIPES, ETERNIPES, ACRIPES, B&W HIGH CONTRAST and the LC STREETLIFE pair — each with its own grain and tone curve.
- The full adjustment set. Exposure, contrast, highlights and shadows, saturation, colour temperature, clarity, grain, and an HSL mixer with a colour picker that samples straight off the photo.
- Geometry. Crop to a fixed ratio or free-form, quarter turns, and a straighten ruler, plus printed frames (classic border, retro instant, wall frame portrait/landscape).
- Finishing. Watermark and GPS stamp, EXIF carried through the export, JPEG written with a proper 300 DPI JFIF header.
- On-device upscaling. A Real-ESRGAN pass runs locally when an export asks for more pixels than the source has — no server sees the photo.
- Recipes. Save, favourite, export and import
.recipefiles; the web build keeps them in your account, the phone build also keeps them on device.
The two builds
| Build | Where | Stack |
|---|---|---|
| iOS / Android | repo root | Expo + React Native, @shopify/react-native-skia for the render pipeline, NativeWind for styling |
| Web | docker/ |
Vite + React, CanvasKit (canvaskit-wasm) for the same pipeline, Fastify + SQLite API for accounts and recipes |
The render engine is shared by design: the web build compiles the app's own
src/utils/* and type definitions unchanged, with @shopify/react-native-skia
aliased to a CanvasKit shim (docker/frontend/src/engine/skiaShim.ts). A look
looks the same on both because it is the same code.
Running the web build
cd docker
cp .env.example .env
docker compose up -d --build
# → http://localhost:8090
Photos never leave the browser: grading, framing, watermarking and JPEG
encoding all run in the visitor's tab; the API only stores accounts and recipe
JSON. See docker/README.md for the layout and the proxy setup.
Running the app
npm install
npx expo start # Expo Go / dev client
npx expo run:android # or run:ios for a native build
Repository layout
App.tsx, src/ the Expo app: screens, tool rail, viewfinder, shaders
docker/ the web build (frontend + API + compose file)
frontend/shared/ vendored copies of the app's types and utils
frontend/src/engine/ CanvasKit shim, export engine, super-resolution
docs/ privacy policy
THIRD_PARTY_NOTICES.md licences of the bundled fonts, models and libraries
Licence
See LICENSE and THIRD_PARTY_NOTICES.md.