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web: make EXPOSURE, EV and HIGHLIGHT mean what Lightroom means

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A stop is a multiplier on light, so EXPOSURE and EV stop living in the sRGB
colour matrix and get a linear-light pass of their own (EXPOSURE_SKSL:
linearise, `C * 2^EV`, re-encode). The matrix keeps CONTRAST: a gain on encoded
values is what made +1 EV land at x1.5 instead of x2. Measured on the neutral
PROVIA sim: EV +1 = x2.011, EV +2 = x3.999, still unclipped at 239.

The pass sits between the matrix and the tone shader, and the tone / cinema /
curve / glow / halation children all sample through it, so HIGHLIGHT finally
sees the value exposure produced instead of the one before it. Recovery keeps
`L + strength * mask * (1 - L)` over `smoothstep(0.50,1.00,luma)`, and the
colour comes back as `color * (luma_new / luma)`: a blown white stays white
(255 -> 255 at -10, 255 at +10), a 0.8 grey loses 33 luma, the midtones beside
it do not move.

AUTO is the histogram the LIGHT tab already draws: weighted mean luminance
(guard 0.001), target 0.48, `log2(0.48 / avg)` clamped to +-2.5 EV, handed to
the same knob. A 0.251 grey asks for EV 0.9 and lands at mean 83.0 against the
83.3 predicted, idempotent on a second press. A stock's own bias rides the same
pass (`SIM_EXPOSURE_BIAS_EV`, VIVID +0.25 EV) and cancels against the knob, so
-1 EXPOSURE on VIVID returns the CLASSIC rendering (measured 0.4149 vs 0.4177).

ponytail: the phone app's `src/utils/colorUtils.ts` keeps the old math, so the
two copies have to move together; recipes saved before this commit (EXPOSURE 2,
HIGHLIGHT +-1) render under the new stop semantics.

Verified on the rebuilt container (BASE=http://localhost:8090):
- web-exposure-probe.cjs 20 PASS / 0 FAIL (neutral 128 -> 128, EV +1 ratio
  2.011, EV +2 ratio 3.999, EXPOSURE +10 ratio 5.62 / -10 ratio 0.172, AUTO
  EV 0.9, HIGHLIGHT -10 on a 204 grey 204 -> 171, white 255 -> 255, no console
  errors)
- sim-exposure-test.cjs 9 PASS / 0 FAIL (classic 0.4149, vivid 0.4531, knob -1
  returning 0.4177, bias 0.0382)
- regression suite, 28 probes: mask 53/0, brush-edit 35/0, heal-idle 23/0,
  heal-zoom-drag 28/0, sims 31/0, sim-vivid 9/0, white-black 4/0, temp-swatch
  33/0, tone-curve clean, compare 25/0, create 52/0, wb-preset 33/0, zoom 25/0,
  save-recent 25/0, web-smoke 9/0 (its export step was stale — EXPORT opens a
  size picker now). panel-test 4 FAIL, histogram-wb 1 FAIL, studio-save-hl and
  progate timeouts, landing-test 6 FAIL ($0.99 pricing) are pre-existing.
- npx tsc --noEmit clean.
This commit is contained in:
3dtours
2026-09-25 17:44:28 +07:00
parent d2115941c7
commit 7e47a153b8
6 changed files with 186 additions and 69 deletions
Download Patch File Download Diff File Expand all files Collapse all files
docker/frontend/src/engine/exportEngine.ts
+42 -22
View File
@@ -22,9 +22,10 @@
import { Skia } from './skiaShim';
import type { Recipe, GPSInfo, FrameId, AspectRatio, CropRect } from '../../shared/types';
import { ASPECT_RATIO_W_H } from '../../shared/types';
import { getSkiaColorMatrix, applyExposureGain } from '../../shared/utils/colorUtils';
import { getSkiaColorMatrix, exposureStops } from '../../shared/utils/colorUtils';
import {
TONE_SKSL,
EXPOSURE_SKSL,
GLOW_SKSL,
CLARITY_SKSL,
getToneUniforms,
@@ -143,6 +144,7 @@ function flush(surface: any): void {
let sharpenEffect: any = null;
let toneEffect: any = null;
let exposureEffect: any = null;
let cinemaEffect: any = null;
let glowEffect: any = null;
let halationEffect: any = null;
@@ -151,11 +153,12 @@ let curveEffect: any = null;
function effects() {
if (!sharpenEffect) sharpenEffect = Skia.RuntimeEffect.Make(CLARITY_SKSL);
if (!toneEffect) toneEffect = Skia.RuntimeEffect.Make(TONE_SKSL);
if (!exposureEffect) exposureEffect = Skia.RuntimeEffect.Make(EXPOSURE_SKSL);
if (!cinemaEffect) cinemaEffect = Skia.RuntimeEffect.Make(CINEMA_SKSL);
if (!glowEffect) glowEffect = Skia.RuntimeEffect.Make(GLOW_SKSL);
if (!halationEffect) halationEffect = Skia.RuntimeEffect.Make(HALATION_SKSL);
if (!curveEffect) curveEffect = Skia.RuntimeEffect.Make(CURVE_SKSL);
return { sharpenEffect, toneEffect, cinemaEffect, glowEffect, halationEffect, curveEffect };
return { sharpenEffect, toneEffect, exposureEffect, cinemaEffect, glowEffect, halationEffect, curveEffect };
}
// FX's HEAL is the one effect whose shader depends on the recipe rather than on
@@ -443,20 +446,24 @@ export async function renderPhoto(input: RenderInput): Promise<RenderResult | nu
const adjustments = recipe.adjustments;
// 3. Colour matrix (+2^EV gain unless the camera already biased the shot).
// The matrix grades into its OWN image first, because a SkPaint runs its
// shader before its colourFilter: with both on one paint the exposure gain
// landed AFTER the tone pass, so +EXPOSURE took the 0.78 a rolled-back
// highlight came out at and pushed it straight back to 1.0 — the HIGHLIGHT
// slider looked dead the moment exposure went up (measured, see the order
// probe). The tone shader's child is the graded image, so the highlight
// mask finally sees the exposed value it is meant to pull back.
const evStops = adjustments.exposureCompensation ?? 0;
const evMatrix = options?.evFromCamera
? getSkiaColorMatrix(recipe.baseFilter, adjustments)
: applyExposureGain(getSkiaColorMatrix(recipe.baseFilter, adjustments), evStops);
const colorFilter = own(Skia.ColorFilter.MakeMatrix(evMatrix));
const matrixIsIdentity = evMatrix.every((v, i) => v === (i % 6 === 0 ? 1 : 0));
// 3. Colour matrix, then the exposure pass (+EV unless the camera already
// biased the shot). The matrix grades into its OWN image first, because a
// SkPaint runs its shader before its colourFilter: with both on one paint the
// exposure gain landed AFTER the tone pass, so +EXPOSURE took the 0.78 a
// rolled-back highlight came out at and pushed it straight back to 1.0 — the
// HIGHLIGHT slider looked dead the moment exposure went up (measured, see the
// order probe). The tone shader's child is the graded-and-exposed image, so
// the highlight mask finally sees the value it is meant to pull back.
//
// The gain itself is the linear-light pass of its own (EXPOSURE_SKSL), not a
// row of the matrix: a stop is a multiplier on light and the matrix runs on
// sRGB-encoded values (see colorUtils.exposureStops). It carries the EXPOSURE
// knob, the stock's bias and the EV knob, all in stops.
const userEv = options?.evFromCamera ? 0 : adjustments.exposureCompensation ?? 0;
const evStops = exposureStops(adjustments, recipe.baseFilter) + userEv;
const matrix = getSkiaColorMatrix(recipe.baseFilter, adjustments);
const colorFilter = own(Skia.ColorFilter.MakeMatrix(matrix));
const matrixIsIdentity = matrix.every((v, i) => v === (i % 6 === 0 ? 1 : 0));
// 3b. Tone shader.
const tone = getToneUniforms(adjustments, recipe.baseFilter);
@@ -473,7 +480,8 @@ export async function renderPhoto(input: RenderInput): Promise<RenderResult | nu
const curveOn = curveIsActive(curve);
let paintShader: any = null;
let gradeImage = skImage;
const graded = (toneIsActive(tone) || cinemaOn || curveOn) && !matrixIsIdentity;
const expOn = evStops !== 0;
const graded = (toneIsActive(tone) || cinemaOn || curveOn || expOn) && !matrixIsIdentity;
if (graded) {
const snapshot = gradeThrough(skImage, width, height, colorFilter);
if (snapshot) {
@@ -487,20 +495,32 @@ export async function renderPhoto(input: RenderInput): Promise<RenderResult | nu
Skia.TileMode.Clamp, Skia.TileMode.Clamp, Skia.FilterMode.Linear, Skia.MipmapMode.None
)
);
// Exposure takes the place of the colour filter on the draw, so it too needs
// the matrix to be IN its child — hence expOn in `graded` above. Everything
// downstream that samples "the image" now samples after the exposure.
let exposeShader: any = null;
if (expOn) {
const { exposureEffect: effect } = effects();
if (effect) exposeShader = own(effect.makeShaderWithChildren([evStops], [imageShaderOf()]));
}
const baseShaderOf = () => exposeShader ?? imageShaderOf();
if (toneIsActive(tone)) {
const { toneEffect: effect } = effects();
if (effect) {
toneShader = own(effect.makeShaderWithChildren(toneUniformArray(tone), [imageShaderOf()]));
toneShader = own(effect.makeShaderWithChildren(toneUniformArray(tone), [baseShaderOf()]));
}
}
if (cinemaOn) {
const { cinemaEffect: effect } = effects();
if (effect) {
const cs = own(effect.makeShaderWithChildren(cinema.flat, [toneShader ?? imageShaderOf()]));
const cs = own(effect.makeShaderWithChildren(cinema.flat, [toneShader ?? baseShaderOf()]));
if (cs) paintShader = cs;
}
}
if (!paintShader && toneShader) paintShader = toneShader;
// The exposure pass must survive as the last member of the chain when nothing
// else is active — it is a shader, not a colour filter, so the draw needs it.
if (!paintShader && exposeShader) paintShader = exposeShader;
// 3e. The curve pass, last: whatever the stock, the matrix, the mixer or the
// seasonal grade did, a point moved on the graph lands the pixel where the
// graph says. The table is an image, so the shader can look it up per channel
@@ -533,7 +553,7 @@ export async function renderPhoto(input: RenderInput): Promise<RenderResult | nu
: null;
const cs =
effect && lutShader
? own(effect.makeShaderWithChildren([], [paintShader ?? imageShaderOf(), lutShader]))
? own(effect.makeShaderWithChildren([], [paintShader ?? baseShaderOf(), lutShader]))
: null;
if (cs) paintShader = cs;
}
@@ -577,7 +597,7 @@ export async function renderPhoto(input: RenderInput): Promise<RenderResult | nu
const strength = (adjustments.hdf ?? 0) / 10;
const sigma = width * (0.006 + 0.024 * strength);
const { glowEffect: effect } = effects();
const srcShader = paintShader ?? imageShaderOf();
const srcShader = paintShader ?? baseShaderOf();
const glowShader =
effect != null ? own(effect.makeShaderWithChildren(glowUniformArray(), [srcShader])) : null;
const glowPaint = own(Skia.Paint());
@@ -645,7 +665,7 @@ export async function renderPhoto(input: RenderInput): Promise<RenderResult | nu
// chips still mean 0/3/6; a sensor stock carries none at any amount.
if (grainAmount > 0 && stock.halation > 0 && stock.halo > 0) {
const { halationEffect: effect } = effects();
const srcShader = paintShader ?? imageShaderOf();
const srcShader = paintShader ?? baseShaderOf();
const haloShader = effect ? own(effect.makeShaderWithChildren(halationUniformArray(stock), [srcShader])) : null;
if (haloShader) {
const haloPaint = own(Skia.Paint());