# Light field (Notchset): prompt.md (v2.0.0)
- id: `light-field` · version 2.0.0 · component · free
- category: Data
- build: one set of files for every shadcn style
- install: `npx shadcn@latest add https://notchset.dev/r/light-field.json`
- npm dependencies: none
- registry dependencies: utils, https://notchset.dev/r/notchset-foundation.json
- docs: https://notchset.dev/components/light-field
- The install command carries everything this item needs (files, CSS, tokens, npm and registry dependencies). Prefer it to copying source by hand.
A wide soft wash of the Signature's light entering from the top right and fading before the page's lower half; in dark it becomes an edge light from the right. Never an orb shape, grain on top, one per page, decoration only..
## Build it
- Stack: React 18.3 or 19, TypeScript, Tailwind CSS v4 utility classes on the foundation's roles, a components.json (imports use its aliases).
- Packages: none beyond React.
- Files: `components/ui/notchset/light-field.tsx`; shared code: `lib/notchset/living.ts`.
- Registry dependencies, installed with it automatically: shadcn `utils` (cn), `notchset-foundation`.
- Builds: one set of files, the same for every shadcn style.
- Exports to keep: `LightField`, and every exported type.
- CSS: the install adds the notchset foundation (its roles, keyframes and motion switch, reading your shadcn tokens for colour) to your global stylesheet once. Nothing to import by hand.
- Re-running `add` (or `--overwrite`) re-applies those rules: put overrides in your own CSS, never in the installed rules.
- Colours: every part reads the foundation's roles (`--ns-canvas`, `--ns-ink`, `--ns-line`, `--ns-signal` …), which read your shadcn tokens (`--background`, `--foreground`, `--border`, `--destructive` …), plus the optional `--success` and `--warning`. Retheme on `:root` or any container; never add Tailwind colour classes inside the component.
- This item reads `--ns-beat`, `--ns-grain`, `--ns-light-1`, `--ns-light-2`, `--ns-light-3`, `--ns-light-spread`, `--ns-light-strength`.
- Retune it (on any ancestor) with the foundation's roles and hooks: `--ns-bad`, `--ns-bad-ink`, `--ns-band`, `--ns-band-edge`, `--ns-band-grade`, `--ns-band-optimal`, `--ns-beat`, `--ns-bezel`, `--ns-canvas`, `--ns-cat-1`, `--ns-cat-2`, `--ns-cat-3`, `--ns-cat-4`, `--ns-cat-5`, `--ns-cat-6`, `--ns-check`, `--ns-chip`, `--ns-control`, `--ns-control-pad`, `--ns-control-sm`, `--ns-deep`, `--ns-deep-ink`, `--ns-deep-ink-2`, `--ns-deep-line`, `--ns-dialog`, `--ns-dialog-lg`, `--ns-dialog-sm`, `--ns-ease`, `--ns-ease-in`, `--ns-ease-panel`, `--ns-ease-pop`, `--ns-field`, `--ns-flood-arc`, `--ns-flood-aurora`, `--ns-flood-behind-1`, `--ns-flood-behind-2`, `--ns-flood-bloom`, `--ns-flood-deep`, `--ns-flood-dial-bloom`, `--ns-flood-glass`, `--ns-flood-grain`, `--ns-flood-image`, `--ns-flood-ink`, `--ns-flood-ink-low`, `--ns-flood-light`, `--ns-flood-mid`, `--ns-flood-pale`, `--ns-flood-pane`, `--ns-flood-pane-edge`, `--ns-flood-pill-ink`, `--ns-flood-ribbon`, `--ns-flood-ribbon-core`, `--ns-flood-shadow`, `--ns-flood-sheen`, `--ns-flood-wash`, `--ns-font-body`, `--ns-font-display`, `--ns-font-mono`, `--ns-font-script`, `--ns-glass`, `--ns-glass-blur`, `--ns-glass-shadow`, `--ns-glow`, `--ns-grain`, `--ns-gutter`, `--ns-header`, `--ns-heat`, `--ns-hover`, `--ns-ink`, `--ns-ink-2`, `--ns-ink-3`, `--ns-ink-4`, `--ns-leading`, `--ns-lift`, `--ns-light-1`, `--ns-light-2`, `--ns-light-3`, `--ns-light-spread`, `--ns-light-strength`, `--ns-line`, `--ns-line-soft`, `--ns-lit-edge`, `--ns-menu-dy`, `--ns-menu-row`, `--ns-mesh`, `--ns-mesh-frost`, `--ns-ok`, `--ns-ok-ink`, `--ns-orb-body`, `--ns-orb-cool`, `--ns-orb-core`, `--ns-orb-dawn`, `--ns-orb-deep`, `--ns-orb-edge`, `--ns-orb-grain`, `--ns-orb-ground`, `--ns-orb-halo`, `--ns-orb-inner`, `--ns-orb-key`, `--ns-orb-lift`, `--ns-orb-limb`, `--ns-orb-limb-from`, `--ns-orb-rim`, `--ns-orb-skin-hi`, `--ns-orb-skin-lo`, `--ns-orb-skin-mid`, `--ns-orb-warm`, `--ns-panel`, `--ns-panel-w`, `--ns-prism-edge`, `--ns-prism-glint`, `--ns-prism-sheen`, `--ns-prism-tint`, `--ns-pulse`, `--ns-radius`, `--ns-radius-card`, `--ns-radius-full`, `--ns-radius-lg`, `--ns-radius-sm`, `--ns-radius-xl`, `--ns-raised`, `--ns-range`, `--ns-row`, `--ns-row-compact`, `--ns-segment`, `--ns-selected`, `--ns-series`, `--ns-series-core`, `--ns-series-lilac`, `--ns-series-tint`, `--ns-shadow-dialog`, `--ns-shadow-float`, `--ns-shadow-panel`, `--ns-sheet`, `--ns-sheet-bottom`, `--ns-side`, `--ns-signal`, `--ns-sleep-awake`, `--ns-sleep-deep`, `--ns-sleep-light`, `--ns-sleep-rem`, `--ns-space-1`, `--ns-space-2`, `--ns-space-3`, `--ns-space-4`, `--ns-space-5`, `--ns-space-6`, `--ns-space-8`, `--ns-space-section`, `--ns-stack-on`, `--ns-standing-critical`, `--ns-standing-in`, `--ns-standing-out`, `--ns-state-doing`, `--ns-state-done`, `--ns-state-review`, `--ns-state-todo`, `--ns-switch-h`, `--ns-switch-w`, `--ns-text-body`, `--ns-text-control`, `--ns-text-display`, `--ns-text-figure`, `--ns-text-headline`, `--ns-text-hero`, `--ns-text-lede`, `--ns-text-meta`, `--ns-text-page`, `--ns-text-record`, `--ns-text-small`, `--ns-text-strong`, `--ns-text-sub`, `--ns-text-title`, `--ns-tile-shadow`, `--ns-time-born`, `--ns-time-color`, `--ns-time-dialog`, `--ns-time-menu`, `--ns-time-page`, `--ns-time-panel`, `--ns-time-toast`, `--ns-tint`, `--ns-tint-ink`, `--ns-toast-bottom`, `--ns-toast-left`, `--ns-touch`, `--ns-tracking-display`, `--ns-tracking-headline`, `--ns-warn`, `--ns-warn-ink`, `--ns-wash-clay`, `--ns-wash-dusk`, `--ns-wash-graphite`, `--ns-wash-ink`, `--ns-wash-sage`, `--ns-wash-sand`, `--ns-weight-light`, `--ns-weight-medium`, `--ns-weight-regular`, `--ns-weight-strong`, `--ns-well`.
- Never add Tailwind colour classes inside the component.
```tsx
import { LightField } from "@/components/ui/notchset/light-field";
```
## Parts
- A single export that takes props.
## Match the original
- Read `components/ui/notchset/light-field.tsx` as the reference implementation before changing or recreating anything, and match it: sizes, colours per theme, motion timings, copy and behaviour.
- If you deviate (a prop you can't honour, a style you changed, a dependency you swapped), say so in your reply, part by part.
- Keep the accessibility contract, the keyboard map and the motion levels listed below.
## Use it when
### Not when
## Built from
- Living (shared helper, ships with it)
## Mistakes
- Recreating the component instead of installing it
## Usage
```tsx
"use client";
import { LightField } from "@/components/ui/notchset/light-field";
export default function LightFieldDemo() {
return (
The page's one light, from the top right
);
}
```
## Props
| Prop | Type | Default | What it does |
|---|---|---|---|
| `at` | `string` | `"73% 59%"` | |
| `still` | `boolean` | `false` | |
Full docs: https://notchset.dev/components/light-field
## Customising
- Colours: every part reads the foundation's roles (`--ns-canvas`, `--ns-ink`, `--ns-line`, `--ns-signal` …), which read your shadcn tokens (`--background`, `--foreground`, `--border`, `--destructive` …), plus the optional `--success` and `--warning`. Retheme on `:root` or any container; never add Tailwind colour classes inside the component.
- Dark mode follows the `.dark` class or `data-theme="dark"` on an ancestor (the shadcn and next-themes conventions).
- Update later: Commit or stash local changes first (or copy the files), so the update can be undone. Read https://notchset.dev/r/changelog.json for the new versions: a major version, an entry marked breaking or a merge says what to change. Then re-run the install with `--overwrite`, on a branch. It replaces the component's files, the shared helper files they import, and the item's CSS rules in the global stylesheet, so review the whole diff (components, shared files, CSS), re-apply your own edits, and run the app's typecheck, tests and build.
## Accessibility contract (preserve when editing)
## Install
```bash
npx shadcn@latest add https://notchset.dev/r/light-field.json
```
Or add the `@notchset` registry to components.json and run `npx shadcn@latest add @notchset/light-field`. Every components.json style gets the same files.
## Continue the workflow
- [Flood tile](https://notchset.dev/components/flood-tile)
- [Hue mesh](https://notchset.dev/components/hue-mesh)
- [Prism edge](https://notchset.dev/components/prism-edge)
## Source
### components/ui/notchset/light-field.tsx
```tsx
// Notchset light-field 2.0.0 · https://notchset.dev/changelog
"use client";
import * as React from "react";
import { cn } from "@/lib/utils";
import { useAwake } from "@/lib/notchset/living";
/*
* Light field: the one light on a page, a large soft field of the Signature's light falling across the page's top
* from the right (by day Amethyst's periwinkle wash on Mineral; by night a tall edge light down the right side, in
* Graphite's silver on the family's near-black). Three soft lights, blurred, with grain on top so it reads as light on
* a material; it drifts within a few percent over a minute and holds still under reduced motion. Never an orb shape,
* never a data hue, never a standing. One per page, placed in the page's top section and spilling past it (behind the
* top bar too). The drift moves a layer drawn once (transform only), pauses while the tab is hidden or the field is
* off screen (living.ts), and stops with `still` where another part is the page's one living thing (the coach's orb).
*
* …
*/
function LightField({ at = "73% 59%", still = false, className }: { at?: string | undefined; still?: boolean | undefined; className?: string | undefined }) {
const ref = React.useRef(null);
useAwake(ref, !still);
/* how far the lights reach is the mode's (--ns-light-spread), so the falloff tightens by night */
const k = (n: number) => `calc(${n}% * var(--ns-light-spread))`;
const [x = 73, y = 59] = at.split(" ").map((v) => parseFloat(v));
return (
{/* the drift moves this layer; the blur is drawn once inside it */}
{/* the grain over the light, so the colour reads as material */}
);
}
export { LightField };
```
### lib/notchset/living.ts
```tsx
// Notchset light-field 2.0.0 · https://notchset.dev/changelog
"use client";
/*
* Living light: the few things in an app that move at rest, and the rules they share (LANGUAGE.md, "Motion that
* lives"). Motion that lives is earned by data (a heartbeat at the live heart rate) or by the page's one light (the
* flood tile's drift, the light field), never more than one per page, and a moment that lands (new results) plays
* once. Plain hooks and functions, no markup; the keyframes live in foundation.css and move transform and opacity
* only, so the compositor runs them without layout or paint.
*
* - Asleep when no one can see it: `useAwake` marks the element `data-ns-asleep` while the tab is hidden or the
* element is off screen, and foundation.css pauses every animation under that mark.
* - Still under less motion: the moving parts carry `data-ns-still`, so the app's switch and the device's both
* hold them (foundation.css).
*/
import * as React from "react";
/** The slowest and fastest heart rates a pulse follows: a beat outside them is drawn at the edge. */
export const BEAT_BPM = [40, 190] as const;
/**
* One heartbeat in seconds at a heart rate (60 / bpm), clamped to 40–190 bpm and rounded to 2 bpm so a reading
* that wobbles by one doesn't restart the beat. No heart rate, no beat (null).
*/
export function beatPeriod(bpm: number | null | undefined): number | null {
if (bpm == null || !Number.isFinite(bpm) || bpm <= 0) return null;
const b = Math.max(BEAT_BPM[0], Math.min(BEAT_BPM[1], Math.round(bpm / 2) * 2));
return Math.round((60 / b) * 1000) / 1000;
}
/* the heartbeat's classes, written whole so Tailwind keeps their keyframes; the period comes from beatStyle */
/** a halo that swells and fades once a beat (the live position) */
export const BEAT_HALO = "animate-[ns-beat_var(--ns-beat)_cubic-bezier(0.2,0.7,0.3,1)_infinite] [transform-origin:center]";
/** a mark that brightens once a beat (the current zone in a heart-rate band) */
export const BEAT_SOFT = "animate-[ns-beat-soft_var(--ns-beat)_cubic-bezier(0.2,0.7,0.3,1)_infinite] [transform-origin:center]";
/** The heartbeat's period for BEAT_HALO or BEAT_SOFT (`--ns-beat`), or none when there's no beat. */
export function beatStyle(bpm: number | null | undefined): React.CSSProperties | undefined {
const s = beatPeriod(bpm);
return s == null ? undefined : ({ "--ns-beat": `${s}s` } as React.CSSProperties);
}
/**
* Marks the element `data-ns-asleep` while the tab is hidden or the element is off screen, so its animations pause
* (foundation.css). `seenAt` is how much of it must show to count as seen (0, any of it; the prismatic sweep waits
* for most of its card). Without an IntersectionObserver (a test) it counts as on screen. It changes the attribute
* only, so scrolling never re-renders the part.
*/
export function useAwake(el: React.RefObject, on = true, seenAt = 0): void {
React.useEffect(() => {
const node = el.current;
if (!node || !on) return;
let seen = true;
const apply = () => {
const a = seen && !document.hidden;
node.toggleAttribute("data-ns-asleep", !a);
};
const io =
typeof IntersectionObserver === "undefined"
? null
: new IntersectionObserver(
(es) => {
seen = es.some((e) => e.isIntersecting && (!seenAt || e.intersectionRatio >= seenAt));
apply();
},
{ threshold: seenAt ? [0, seenAt] : 0 },
);
io?.observe(node);
document.addEventListener("visibilitychange", apply);
apply();
return () => {
io?.disconnect();
document.removeEventListener("visibilitychange", apply);
node.removeAttribute("data-ns-asleep");
};
}, [el, on, seenAt]);
}
/** How long a moment that lands plays (the prismatic edge's one sweep), in ms. */
export const ARRIVAL_MS = 1200;
const readSeen = (k: string) => {
try {
return localStorage.getItem(k);
} catch {
return null;
}
};
const writeSeen = (k: string, v: string) => {
try {
localStorage.setItem(k, v);
} catch {}
};
/**
* A moment that lands once: `[playing, done]`. Playing turns on when `key` (what arrived, a result set's id) is new,
* and off when the part calls `done` (its animation ended, or there was none to play). New means it changed while
* the part is mounted, or it differs from the one this device last saw (kept under `remember`, when given). A first
* sight with nothing remembered, a re-render and a remount of the same key never play it.
*/
export function useArrival(key: string | null | undefined, remember?: string | undefined): readonly [boolean, () => void] {
const [playing, setPlaying] = React.useState(false);
const last = React.useRef(undefined);
React.useEffect(() => {
if (key == null) return;
const before = last.current === undefined ? (remember ? readSeen(remember) : null) : last.current;
last.current = key;
if (remember) writeSeen(remember, key);
if (before != null && before !== key) setPlaying(true);
}, [key, remember]);
const done = React.useCallback(() => setPlaying(false), []);
return [playing, done] as const;
}
```
The foundation (the tokens listed above, keyframes and motion levels) installs once with the first component; its CSS is public at https://notchset.dev/r/notchset-foundation.json.