TEMP was a kelvin and nothing else, and the seven presets were seven numbers
the two platforms disagreed about: AUTO 5500, DAYLIGHT 5600, DAYLIGHT -3R
5800, CLOUDY 6500, SHADE 7500 here and 8000 in both recipe-creation forms,
TUNGSTEN 3200, FLUOR 4000. A chip tapped in the recipe panel and the same
chip tapped on the photo printed different frames.
The presets are now the phone's own WB_PAIRS — kelvin AND tint — in all three
places, so every chip lands the same pair on either platform:
AUTO 5500/0 DAYLIGHT 5500/0 DAYLIGHT -3R 5500/-3 CLOUDY 6500/1
SHADE 7500/2 TUNGSTEN 3200/0 FLUOR 4000/3
SHADE read 8000K in RecipeCreatePanel and RecipeCreateModal; it is the WB
tab's 7500K/+2 now, so a recipe created in a form prints what the same chip
prints on the photo.
AUTO and DAYLIGHT stand for one pair, so the pair alone cannot say which of
the two is lit. TEMP is therefore keyed by preset and not by value: `wbChoice`
remembers the chip last tapped (the phone's own wbChoice), and `wbValue()`
answers it only while the engine pair still matches, else the first preset
that pair maps to, else the bare kelvin. `wbLabel()` names that pick on the
chip, which now always carries one: TEMP AUTO at the neutral pair, TEMP SHADE
on a preset, TEMP 6300K on the app's own default recipe where a hand-dragged
ruler landed. Measured on the deployed build (`wb-preset-test.cjs`, 33/0):
AUTO and DAYLIGHT print the same frame to the level, DAYLIGHT -3R moves the
green away from DAYLIGHT at the same 5500K, the ruler warms monotonically
across TUNGSTEN 0.525 / FLUOR 0.730 / AUTO 1.000 / CLOUDY 1.141 / SHADE 1.295,
a hand-drag to 10000K names the chip `10000K` and warms the picture R x1.183
B x0.793, SHADE tapped after that drag restores the pair 7500/2 and prints the
same frame the first tap did (R 156.8 vs 156.8), and a temperature drag leaves
a preset's tint standing (FLUOR's +3).
kelvinToRGB itself was the other half. It took the ratio of the sRGB-ENCODED
blackbody colours and square-rooted it, which measured R x1.06 / B x0.89 from
5500K to 10000K — a shift a swatch shows and a sunset does not. White balance
is a gain on LIGHT, so the ratio is taken in linear light now
(`planckianLinear`) and tamed by a new `KELVIN_TAME = 0.5`: the same 10000K
moves the frame R x1.16 / B x0.76, and 2500K its mirror, which is what a
camera does with its WB set 4500K off the scene. One constant scales the whole
ruler and both platforms carry the same one. Measured through the app
(`_temp-probe.cjs`, gains against 5500K): 2500 R x0.569 B x1.640, 4000 R x0.866
B x1.197, 6500 R x1.057 B x0.940, 10000 R x1.140 B x0.759 — the readout is
compressed against the raw gain because the cast lands on encoded, clipping
pixels, which is the reason for the tame in the first place.
ponytail: no scene meter, so AUTO stays the neutral 5500K/0 pair and is a name
for it, not a measurement. Add one when the engine reads the frame.
ponytail: KELVIN_TAME scales the whole ruler both ways. Split it into a warm
and a cool constant only if the two ends are ever asked to move apart.
Verified: `wb-preset-test.cjs` 33/0 and `_temp-probe.cjs`, `sims-test.cjs`
31/0, `fx-mono-test.cjs` 15/0, `wm-font-test.cjs` 38/0 against the deployed
build; web `tsc --noEmit` clean, the phone's scoped check down to its two
pre-existing `skiaImage.ts` nulls.
3dtours
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