Raising DEHAZE drew bright copies of every dark detail in the photo, stacked alongside it. The prior was the reason, and the prior was read wrongly. The 5x5 patch of DEHAZE_SKSL was sampled inline, five taps out at 0.625% of the frame's width each — one tap every 6.67 pixels of the 1067-pixel preview, an average spacing over a 26-pixel patch that is meant to be the minimum over it. A detail thinner than that spacing therefore sat between two taps on one row and under a tap on the next, and the transmission swung between "this patch holds a shadow, leave it alone" and "this patch is all haze, divide hard" with a 7-pixel period around every dark thing on the frame. A rising DEHAZE drew that period: `t` is a per-pixel divisor, so the rows of the detail that were left alone stayed put while the rows read as haze came up bright, and the 13.3-pixel column spacing made the next copy and the copy after that. That is what was stacking. Measured on a synthetic frame of sloped haze with four one-pixel dark lines: the old shader departs from the clean correction by +58 to +102 codes (8-bit) at exactly +/-6.67 and +/-13.3 pixels around each line — the two spacings, in both directions, which is the whole signature of the bug. That frame is otherwise flat, so those deviations are the copies. Three things had to be got right, and each is the smallest fix that removes one of them: - The patch is no longer sampled. The caller builds the dark channel as an image — a 64x64 copy of the frame, smallest channel over a cell-wide neighbourhood, then two box passes — and hands it to the pass as its second child, so the shader's own `dark.eval` IS the patch: one cell covers a whole neighbourhood rather than sampling it, and the bilinear upscale interpolates it back up with no period left in it. The box passes are the doc's soft matting in the one form free here — the map is smoothed, not the pixels. The copy is made with drawImageRect, rect to rect: a paint shader drawing a 64x64 rect reads only the source's 4x4 corner, and a one-pixel line in such a copy lands at 166, i.e. pure haze, because the cell covering it is mostly sky. - What travels as that image is the dark channel and not the transmission. t is 1 + 0.95 at the negative end of the knob, more than a channel can carry, so a copy of t would arrive here clipped to 1 and "put the scattered light back" would become a pass that returns its input. The dark channel is 0..1 by construction and the signed amount stays a uniform, where it costs no range — the knob keeps both of its directions. Swept on the real photo, DEHAZE -100 moves 779,237 pixels brighter and 703,114 darker (worst 110 codes) while the same frame at 0 either side of it moves exactly none, and +100 moves the frame the other way at atmosphericLight [0.93155, 0.90980, 0.93084]. - The pass was reading a shader that does not exist yet. `effects()` is what it asks now, not the module variable: nothing above DEHAZE has asked for the effect, so on the first render the variable is still null and the knob stayed dead until some later render happened to fill it in. A map this small only covers the frame if it is told to, and the matrix that does it is the last thing that had to be right: CanvasKit reads a shader's local matrix as the map's own pixels to the frame's, so the 64x64 copy needs frame over map, `[W/64, 0, 0, 0, H/64, 0, 0, 0, 1]`. Without it the pass covers only the top-left 64 pixels and clamps every pixel past them onto the map's last texel — one constant t over the whole photo, a global inversion and not a dehaze. Measured against the ideal ramp, `scaled(n/w)` clamps the same way; the reciprocal lands on it. The knob is left to over-correct at the top of its range, and that is deliberate. A hazy sky still goes white and a saturated colour beside a dark edge still deepens: `(c - a)/t + a` with an airlight near 0.93 and a plain clamp, which is the arithmetic the doc asks for. It is smooth on the frame — 6x zoom panels of the hazy frame at DEHAZE 100 show one wide gradient and no band repeating at any period — so no knee is added to soften a correction that is no longer producing the symptom. If that side ever needs taming, DEHAZE_MAX_OMEGA is the one number. The MASK's DEHAZE still samples the old 5x5 patch inline (gradientMask.ts, unchanged): the frame-wide pass is what the report was about and what is fixed here. Verified: the synthetic harness over four patch configurations puts the new shader at zero deviation from the clean correction at N=64 — the 16.7-pixel cell swallows the test line, which is why the real photo is the judge. The real photo through the running app, with the slider swept 0, 100, -100, 0, is exact at both zero points and moves the frame at both ends, and its zoomed panels at DEHAZE 100 — roof, floor and a wooden rail at 3x and 6x — show the remaining change as one smooth region, the blue of a tarp and the green of a floor stain deepening where the haze was hiding them, with nothing repeated around the dark detail that used to copy itself. npx tsc --noEmit clean, npm run build clean, scripts/mask-wb-check.mjs and scripts/highlight-knee-check.mjs both pass. Co-authored-by: PenguinHarness <noreply@penguin.local>
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.