web: move WHITE/BLACK onto the WB tab as per-channel points

LIGHT already spends its slope budget on the tone knees, so the two end
points were doing nothing a tone knob could not. On WB they act on each
channel's own distance from the end: the darker channel of a shadow and
the brighter channel of a highlight move most, which neutralises a cast
at the toe and the shoulder. Both shuffles stay cubic in the channel
value, so every channel's curve is still monotonic (>= 0.46).

docker/frontend/shared/types/index.ts

@@ -80,8 +80,8 @@ export interface ColorAdjustments {
   wbBlue?: number; // Fuji WB fine-tune, Blue axis (-9..9) — extra blue-channel gain
   highlight: number; // -10 to +10 (- pulls highlights down / roll, + brightens)
   shadow: number; // -10 to +10 (+ lifts shadows, - deepens)
-  whites?: number; // -10 to +10 (white point: the very top of the tone curve)
-  blacks?: number; // -10 to +10 (black point: the very toe of the tone curve)
+  whites?: number; // -10 to +10 (WB white point: per channel, the shoulder)
+  blacks?: number; // -10 to +10 (WB black point: per channel, the toe)
   denoise: number; // -10 to +10 (+ = blur sigma; - = add film grain back)
   clarity: number; // -10 to +10 (mapped to matrix convolution / bloom)
   grain: number; // 0 to 10 (mapped to noise turbulence opacity/scale)

docker/frontend/shared/utils/paramDefs.ts

@@ -105,30 +105,6 @@ export const PARAM_DEFS: {
       get: (a) => a.shadow ?? 0,
       set: (v) => ({ shadow: v }),
     },
-    {
-      // The end points of the tone curve: WHITE lifts/crushes the top, BLACK the
-      // toe. Same range as the CREATE form's rows, so a look round-trips.
-      key: 'whites',
-      label: 'WHITE',
-      min: -10,
-      max: 10,
-      step: 1,
-      defaultValue: 0,
-      display: sign,
-      get: (a) => a.whites ?? 0,
-      set: (v) => ({ whites: v }),
-    },
-    {
-      key: 'blacks',
-      label: 'BLACK',
-      min: -10,
-      max: 10,
-      step: 1,
-      defaultValue: 0,
-      display: sign,
-      get: (a) => a.blacks ?? 0,
-      set: (v) => ({ blacks: v }),
-    },
   ],
   wb: [
     {
@@ -153,6 +129,32 @@ export const PARAM_DEFS: {
       get: (a) => a.tint ?? 0,
       set: (v) => ({ tint: v }),
     },
+    {
+      // The two points live on WB, not on LIGHT: they shift each channel's own
+      // end of the ramp, which balances a cast at the toe and the shoulder
+      // rather than adding another tone knob. Same range as the CREATE form's
+      // rows, so a look round-trips.
+      key: 'whites',
+      label: 'WHITE',
+      min: -10,
+      max: 10,
+      step: 1,
+      defaultValue: 0,
+      display: sign,
+      get: (a) => a.whites ?? 0,
+      set: (v) => ({ whites: v }),
+    },
+    {
+      key: 'blacks',
+      label: 'BLACK',
+      min: -10,
+      max: 10,
+      step: 1,
+      defaultValue: 0,
+      display: sign,
+      get: (a) => a.blacks ?? 0,
+      set: (v) => ({ blacks: v }),
+    },
   ],
   filters: [
     {

docker/frontend/shared/utils/toneShader.ts

@@ -25,9 +25,11 @@ import { BaseFilter, ColorAdjustments } from '../types';
 //       (Fuji extended DR); 0/auto/DR100 = no extra curve.
 // hl  - highlight -1..1: + lifts toward white, - rolls the bright side down.
 // sh  - shadow    -1..1: + lifts the dark side, - deepens it.
-// wh  - white point -1..1: + pushes the top of the ramp toward white, - rolls
-//       it down. Cubic end-weight, so it never fights the HL knee.
-// bl  - black point -1..1: + lifts the toe (faded black), - crushes it.
+// wh  - white point -1..1: per channel, from the WB tab. + lifts the shoulder,
+//       - rolls it down. Cubic weight in the channel's own value, so the
+//       brighter channel of a highlight moves most.
+// bl  - black point -1..1: per channel. + lifts the toe (faded black), -
+//       crushes it; the darker channel of a shadow moves most.
 // vib - vibrance -1..1: chroma-masked saturation. It rides along in this shader
 //       (rather than the colour matrix) because it needs per-pixel chroma:
 //       already-vivid pixels move least, so skins/skies deepen without the neon
@@ -66,20 +68,20 @@ vec4 main(vec2 xy) {
   // Dynamic range: gentle shadow lift + highlight roll (protect brights).
   o += dr * 0.12 * shMask * (1.0 - t);
   o -= dr * 0.18 * hlMask * t;
-  // White/black point. The HL/SH knees above already spend the slope budget
-  // (each just under 1.0), so these two use cubic end-weights instead of
-  // another smoothstep: only the last/first stretch of the ramp moves, and the
-  // derivative stays >= 1 - 3*0.18 = 0.46 for every combination, so the curve
-  // can never invert. + lifts that end (faded blacks / brighter whites),
-  // - digs it in (true black / rolled white).
-  o += bl * 0.18 * (1.0 - t) * (1.0 - t) * (1.0 - t);
-  o += wh * 0.18 * t * t * t;
   o = clamp(o, 0.0, 1.0);
   // Lightness takes the curve, hue stays: the colour difference is gained
   // only part-way so darkening cannot collapse a colour to black and lifting
   // cannot blow a dark saturated colour out to white.
   float cg = clamp(o / max(t, 0.0004), 0.55, 1.35);
   rgb = clamp(vec3(o) + (rgb - vec3(t)) * cg, 0.0, 1.0);
+  // WHITE/BLACK points, per channel. The weight is cubic in the channel's own
+  // distance from the end, so in the shadows the darker channels move most and
+  // in the highlights the brighter ones do: the two points pull R, G and B
+  // toward a common toe and shoulder, which is a white-balance move (it
+  // neutralises a cast) and not another tone slider. Each channel's curve is
+  // still monotonic — 1 - 3*0.18 = 0.46 at worst — so no value can invert.
+  vec3 dk = 1.0 - rgb;
+  rgb = clamp(rgb + bl * 0.18 * dk * dk * dk + wh * 0.18 * rgb * rgb * rgb, 0.0, 1.0);
   // Split tone (stock look): the shadows and the highlights may each carry
   // their own tint, so the two ends of the curve can drift opposite ways
   // (Classic Neg: green-cyan darks, warm brights) without touching mid-greys.
@@ -189,8 +191,8 @@ export interface ToneUniforms {
   dr: number; // 0..1
   hl: number; // -1..1 (adjustments.highlight / 10)
   sh: number; // -1..1 (adjustments.shadow / 10)
-  wh: number; // -1..1 (adjustments.whites / 10 — white point)
-  bl: number; // -1..1 (adjustments.blacks / 10 — black point)
+  wh: number; // -1..1 (adjustments.whites / 10 — WB white point, per channel)
+  bl: number; // -1..1 (adjustments.blacks / 10 — WB black point, per channel)
   vib: number; // -1..1 (adjustments.vibrance / 10)
   shT: [number, number, number]; // shadow split-tone RGB bias, -1..1
   hlT: [number, number, number]; // highlight split-tone RGB bias, -1..1