# Slope Chart (Lumen Halo): prompt.md (v1.0.0)

- id: `lumen-slope-chart` · version 1.0.0 · component · pro (Pro)
- category: Charts
- build: Base UI (one set of files; its dependencies follow the build)
- install (this build): `npx shadcn@latest add @beautiful-ui-pro/lumen-slope-chart`
- npm dependencies: recharts@^3
- registry dependencies: utils, @beautiful-ui/lumen-chart, @beautiful-ui/lumen-stat, https://beautiful-ui.dev/r/lumen-foundation.json
- docs: https://beautiful-ui.dev/components/lumen-slope-chart
- The install command carries everything this item needs (files, CSS, tokens, npm and registry dependencies). Prefer it to copying source by hand.

Before and after for a handful of things, one line each on one shared scale, so the steepness is the change. Both ends carry their values and a rank move sits beside the after value when the order changes.

## Build it
- Stack: React 19 (`ref` is a plain prop), TypeScript, Tailwind CSS v4 utilities, a shadcn-initialised project with the `@/*` alias.
- Packages: `recharts@^3`.
- Files: `components/ui/lumen/charts/slope-chart.tsx`, `components/ui/lumen/charts/chart-frame.tsx`, `components/ui/lumen/charts/cartesian.tsx`.
- Registry dependencies, installed with it automatically: shadcn `utils` (cn), `lumen-chart`, `lumen-stat`, `lumen-foundation`.
- Builds: one set of files for both, but its dependencies come in Base UI and Radix builds. Install the one that matches the project (see Install): a free item's bare URL installs the Base UI build of it and its dependencies.
- Exports to keep: `SlopeChart`, and every exported type.
- CSS: the install merges this item's rules (the registry `css` field) into your global stylesheet, in `@layer components`, and adds the lumen foundation (tokens, keyframes, motion levels) 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.
- Tokens: retheme with the `--lumen-*` custom properties (`--lumen-accent`, `--lumen-accent-foreground`, `--lumen-accent-text`, `--lumen-bad`, `--lumen-bad-text`, `--lumen-chart-accent`, `--lumen-chart-accent-foreground`, `--lumen-chart-accent-text`, `--lumen-focus`, `--lumen-good`, `--lumen-good-text`, `--lumen-hairline`, `--lumen-ink`, `--lumen-muted-ink`, `--lumen-series-1`, `--lumen-series-2`, `--lumen-series-3`, `--lumen-series-4`, `--lumen-series-5`, `--lumen-series-6`, `--lumen-warn`, `--lumen-warn-text`); this item's CSS also reads `--lumen-font-mono`, `--lumen-font-sans`, `--lumen-radius-k`. Never add Tailwind colour classes inside the component.

```tsx
import { SlopeChart } from "@/components/ui/lumen/charts/slope-chart";
```

## Parts

| Part | data-slot | What it is for |
|---|---|---|
| `SlopeChart` | — | The lines, labels, rank moves, states, summary and table. |

## Sound
- Keep every `data-slot` and `data-sound` attribute: the sound layer reads them.
- Installing this item adds no audio. Nothing plays until the app mounts `GlassSoundProvider` once (install: `npx shadcn@latest add https://beautiful-ui.dev/r/glass-sound.json`, import from `@/components/beautiful-ui/glass-sound`); `GlassSoundToggle` is its mute control. Without a provider the audio engine never loads.

## Match the original
- Read `components/ui/lumen/charts/slope-chart.tsx`, `components/ui/lumen/charts/chart-frame.tsx`, `components/ui/lumen/charts/cartesian.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
- slope chart, before and after, period comparison, rank change, year over year, two points in time
- Two points in time for 3–10 things, where who rose and who fell matters more than the path between

### Not when
- Many points in time: use a Line Chart
- More than about ten lines: the labels crowd; use a table or a Bar Chart of the change

## Mistakes
- Keep data and config stable (outside the component, or memoised)
- Both ends share one scale on purpose; don't normalise the values first or the slopes stop meaning change

## Usage

```tsx
"use client";
import { SlopeChart } from "@/components/ui/lumen/charts/slope-chart";

const channels = [
  { channel: "search", q2: 420, q3: 380 },
  { channel: "social", q2: 260, q3: 410 },
  { channel: "partners", q2: 190, q3: 240 },
  { channel: "email", q2: 310, q3: 290 },
];

const config = {
  search: { label: "Search", color: "var(--chart-1)" },
  social: { label: "Social", color: "var(--chart-2)" },
  partners: { label: "Partners", color: "var(--chart-3)" },
  email: { label: "Email", color: "var(--chart-4)" },
};

export function SignupsByChannel() {
  return <SlopeChart data={channels} name="channel" from="q2" to="q3" fromLabel="Q2" toLabel="Q3" config={config} label="Sign-ups by channel, Q2 to Q3" />;
}
```

## Props

| Prop | Type | Default | What it does |
|---|---|---|---|
| `data / name / from / to` | `Row[] / field / field / field` |  | One row per line: its name, the before value and the after value. |
| `fromLabel / toLabel` | `string / string` |  | The two column headings. Default: the field names. |
| `config` | `ChartConfig` |  | Colour and label per line name. Unlisted lines take the series colours in order. |
| `ranks` | `boolean` | `true` | Show rank moves (▲2, ▼1) beside the after values. |
| `valueFormat` | `StatFormat \| (n) => string` |  | Numbers at both ends, in the table and summary. |
| `active / onActiveChange / onSelect` | `string \| null / (name) => void / (name) => void` |  | The focused line, controlled; and a line was clicked or Enter pressed. |
| `height` | `number` | `320` | Plot height in px. |
| `motion` | `"full" \| "subtle" \| "off"` | `"full"` | Lines draw from before to after in turn; reduced motion always wins. |
| `loading / error / emptyText / label` | `boolean / string / string / string` |  | States in words with the height held, and the chart's accessible name. |

Full docs: https://beautiful-ui.dev/components/lumen-slope-chart

## Customising
- Motion: `motion="full"` (default) | `"subtle"` | `"off"`. prefers-reduced-motion is always respected.
- Colours: set the `--lumen-*` tokens on `:root`, or on a container with the `lumen-scope` class to retheme one area. Add the `lumen-inherit` class to follow your shadcn palette instead (`--chart-N`, `--destructive`).
- Dark mode follows the `.dark` class on an ancestor (the shadcn and next-themes convention).
- Update later by re-running the install with `--overwrite` (review the diff if you edited it). Changelog: https://beautiful-ui.dev/r/changelog.json

## Keyboard

| Keys | Action |
|---|---|
| Tab | Focus the chart |
| ↑ / ↓ / ← / → | Move between lines; the live region says the line |
| Home / End | First or last line |
| Enter / Space | Select the focused line (onSelect) |
| Escape | Clear the focus |

## Performance

- Plain SVG, two dots and a line per row; no chart library work at runtime

## Responsive

- Scales with its container (a fixed-ratio drawing); labels nudge apart so they never overlap; long names truncate on narrow cards

## Motion inventory

| Interaction | What moves |
|---|---|
| Draw | Each line draws from before to after, one after another (motion="subtle" is quicker) |
| Focus | The focused line thickens and the rest fall back |

## Accessibility contract (preserve when editing)
- A labelled figure; the lines are one tab stop (role application) and arrow keys move between them, said through a polite live region with the change and rank move
- Values are written at both ends and rank moves use ▲ / ▼ with a number, so colour is never the only cue
- A one-sentence summary and the full table (before, after, change, rank) for screen readers; missing values are named

## Install

```bash
npx shadcn@latest add @beautiful-ui-pro/lumen-slope-chart
```

Pro item: needs the `@beautiful-ui-pro` registry in `components.json` and `BEAUTIFUL_UI_TOKEN` in `.env.local` (https://beautiful-ui.dev/account). Setup: https://beautiful-ui.dev/docs/pro. Your components.json `style` picks the build: radix-*, new-york and default get Radix, base-* gets Base UI.

## Credits
- Built on shadcn/ui charts conventions (https://ui.shadcn.com/charts)

The lumen foundation (the tokens listed above, keyframes and motion levels) installs once with the first component; its CSS is public at https://beautiful-ui.dev/r/lumen-foundation.json.