Files

T

3dtours 166a677590 light: the tone ramp is four bumps on the identity, not straight segments between five knots — a knot is an angle, an angle in a tone curve is a Mach band, and the wedge reads the seams: BLACK +100 broke at 0.030 with 105 of second difference, HIGHLIGHT -100 at 0.747 with 72

The ramp was a0..a4 with the pixel's base interpolated straight between them.
A segment meets its neighbour at an ANGLE, and the second derivative of a tone
curve is what a gradient reads as a band — so a knob left a line across the
mid-tones, worst exactly where it was reported: BLACK +100 put its whole lift
inside 0.25 and the stretch from 0.25 up came back identical to the untouched
frame (the "transition stays grey" it was reported for), and HIGHLIGHT -100
folded a seam into 0.747, between the highlights it pulled and the shadow it
left under them.

Measured on a 1024-step luma wedge through the exported pass, second
difference through a ±1% box: BLACK +100 read 105 at 0.030 against 0.000 from
0.25 up, HIGHLIGHT -100 read 72 at 0.747. Step of the first derivative across
the knots: 0.955 at 0.25 and 1.146 at 0.75 — the curve arrived folded, and
1.146 is a sign flip, not a bend.

So each knob is now a BUMP on the identity, peaking on its own knot — BLACK on
0.00, SHADOW on 0.25, HIGHLIGHT on 0.75, WHITE on 1.00 — with the kernel
(1-u^2)^2 over a half-width (a half of the ramp for the two ends, whose knots
ARE the ends, a quarter for the two heads). Level at u = 0, so a knot moves
without a fold at its own top; level at u = 1, so a move lands on the identity
and on its neighbour without an angle; C1 everywhere between. The two bumps of
a half meet on 0.50 both on zero, which is the same fixed midpoint as before,
and DR still moves the same knots (0.12 on the toe, 0.18 on the head, half of
each on the heads beside them).

A sum of bumps can overshoot where two steep sides land on one stretch — past a
slope of 1 the curve runs BACKWARDS, a worse band than the seams this replaces,
and it is reachable: DR alone was under it, BLACK and SHADOW +100 together were
not (unguarded min slope -0.0141). The guard reads each pair at its own
steepest points, 8/(3*sqrt(3))/w per unit amplitude (TONE_BUMP_SLOPE_HALF 3.0792,
TONE_BUMP_SLOPE_QUARTER 6.1584), holds the two under one and gives them up
together past it. A single knob never reaches it (a full BLACK is 0.77, a full
SHADOW 0.77), so every slider keeps its whole travel; the worst case is DR at
full, which gives up a tenth of its head roll (0.18 -> 0.8376 on the head), and
BLACK with SHADOW both at +100, which arrive at 0.65 of their own lift instead
of folding. Guarded, the sweep over five levels of all four knobs and DR reads
a min slope of +0.0183 and a max of 1.9937, with the largest slope jump 0.00005.

After: the same wedge, the same pass. The knot steps are 0.096 at 0.25 and
0.478 at 0.75, with no sign flip — C1 across the knot instead of a fold. BLACK
+100 now carries the rework out of its own quarter: +0.139 at 0.25, +0.101 at
0.30, +0.033 at 0.40, 0.000 at 0.50, where it used to read 0.000 from 0.25 all
the way up. HIGHLIGHT -100 keeps its lift (-0.126 peak against -0.121 before) and
spends it over the quarter instead of into a line. Every knob on zero is the
identity to the last bit — the pass also runs for the stock split tones and for
DR alone — and 0.50 is still the one value no knob moves.

Checks: tone-base-check.mjs now runs the bump and the guard as arithmetic
beside the shader (with the negative control: the unguarded pair still folds,
the guard is what stops it). highlight-knee-check.mjs reads the kernel and the
two slope constants off the source, pins the four amplitudes and the guard, and
sweeps the travel of every knob as before. All ten checks that run without a
browser pass, build clean.

Skipped: the guard's ceiling is a constant, not a search for the widest travel
that still clears a band we cannot see. Add when a frame shows a band the
deflections in hand cannot explain.

2026-09-30 21:24:01 +07:00

backend

PRO cutoff: an account that signed up before 2026-12-01 keeps the whole studio with its Activated Pro box ticked by the calendar, signups from the cutoff on start basic

2026-09-30 12:22:59 +07:00

frontend

light: the tone ramp is four bumps on the identity, not straight segments between five knots — a knot is an angle, an angle in a tone curve is a Mach band, and the wedge reads the seams: BLACK +100 broke at 0.030 with 105 of second difference, HIGHLIGHT -100 at 0.747 with 72

2026-09-30 21:24:01 +07:00

.env.example

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.gitignore

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docker-compose.yml

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README.md

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README.md

RecipesCam web — self-contained stack

A Docker-hosted web build of RecipesCam. Everything it needs is in this folder: move it to another machine, run two commands, and the app is up. It does not need the React Native project around it.

cp .env.example .env
docker compose up -d --build
# → http://localhost:8090

What runs where

Service	Image	Role
`frontend`	`nginx:1.27-alpine` (built by `frontend/Dockerfile`)	Static SPA + `/api/` reverse proxy
`api`	`node:22-slim` (built by `backend/Dockerfile`)	Accounts + saved recipes, SQLite on `./data`

frontend resolves api through Docker's embedded DNS and proxies /api/* to it — that is why the API container is named api and why it is not published on the host. Only ${WEB_PORT:-8090} is exposed.

Photos never leave the browser. The CanvasKit render pipeline (grade, frame, watermarks, JPEG encode) runs in the visitor's tab; the API only stores recipes as JSON.

Layout

docker-compose.yml      the stack
.env.example            WEB_PORT
data/                   SQLite (created on first run, gitignored)
backend/                Fastify + better-sqlite3 API, own Dockerfile
frontend/               Vite + React + CanvasKit SPA, own Dockerfile + nginx.conf
  shared/               vendored copies of the app's types + utils (see below)
  src/engine/           skiaShim.ts (CanvasKit) + exportEngine.ts (render pipeline)
                        + session.ts (localStorage/IndexedDB studio persistence)

Vendored files

frontend/shared/{types/index.ts,utils/*.ts} are byte-identical copies of src/types/index.ts and ten src/utils/*.ts files from the React Native project (@shopify/react-native-skia is aliased to src/engine/skiaShim.ts in vite.config.ts + tsconfig.json, so those files compile unchanged):

cinemaShader colorUtils defaultRecipes exifWrite frameUtils jpegDpi paramDefs recipeShare skiaImage toneShader.

The landing page needs no CDN: frontend/public/assets/fonts/*.woff2 are the seven self-hosted faces behind the three font groups the Themes menu offers (Plus Jakarta Sans / Inter / JetBrains Mono, Fraunces / Be Vietnam Pro / Courier Prime, Be Vietnam Pro / Space Mono — all SIL OFL, pulled from Google Fonts, vietnamese + latin + latin-ext subsets), and frontend/public/assets/samples/s*.jpg are the six placeholder negatives the film strip, preset tester and QR card show (swap them for real graded stills whenever we have them). Its one foreign request is the QR image from api.qrserver.com, which degrades to an empty slot offline.

When the app changes one of them, copy it back in — the renderer is only "parity" for as long as these stay in sync:

cd <repo>/docker/frontend/shared/utils
cp <repo>/src/utils/<name>.ts .

Operations

docker compose logs -f api        # API log
docker compose restart api        # after backend/src changes (rebuild: --build)
docker compose down               # stop; ./data survives

Backup is the ./data folder — that is the whole database.

Checks

curl -s http://localhost:8090/api/health          # {"ok":true}
curl -sI http://localhost:8090/                   # 200, index.html

Then open the UI, drop a photo in, and confirm the preview shows the picture and EXPORT downloads a JPEG that opens. The preview going solid black while the export still reports a plausible size is the one failure mode worth knowing: it means the CanvasKit GPU surfaces lost their shared GrDirectContext (see frontend/src/engine/skiaShim.ts), and with no GPU the raster fallback renders the same pipeline correctly, just slower.