@hemicycle/react

React component for rendering parliament-style hemicycle seat charts.

@hemicycle/react is the React wrapper around @hemicycle/vanilla. Drop in a <Hemicycle> component, pass your seat data as props, and get a fully rendered SVG chart that re-renders reactively on changes.

Features

• Single <Hemicycle> component — configure layout and data entirely through props
• Per-seat React wrappers — wrap any seat with a custom React node (tooltips, popovers, links, etc.)
• Per-seat SVG props — attach onClick, aria-*, data-*, and any other SVG attributes to individual seats
• All @hemicycle/vanilla options — shapes (arc, rect, circle), aisles, mirroring, radii, and more
• TypeScript generics — type your seat data end-to-end with HemicycleProps<T>

Installation

npm install @hemicycle/react

Requires React ≥ 18 and Node.js ≥ 18.

Quick Start

import { Hemicycle } from "@hemicycle/react";

export function ParliamentChart() {
  return (
    <Hemicycle
      rows={7}
      totalSeats={577}
      innerRadius={40}
      outerRadius={95}
      width={800}
      height={420}
    />
  );
}

API

<Hemicycle>

All props are optional. Accepts all @hemicycle/vanilla config options plus:

| Prop | Type | Description | | ------------ | ------------------------------- | ------------------------------------------------- | | data | HemicycleData<T>[] | Seat data array (see below) | | svgProps | React.SVGProps<SVGSVGElement> | Extra props forwarded to the root <svg> element | | seatConfig | SeatConfig<T> | Default visual style and behavior for all seats |

SeatConfig<T>

Extends the vanilla SeatConfig (shape, color, borderRadius, radius) with two React-specific additions:

| Option | Type | Description | | --------- | -------------------------------- | ------------------------------------------------- | | wrapper | (content, data) => ReactNode | Wraps each seat's <path> in a custom React node | | props | React.SVGProps<SVGPathElement> | Default SVG props applied to every seat <path> |

Seat data

Each item in the data array identifies a seat by index or by coordinates, exactly as in @hemicycle/core, and may include a per-seat seatConfig to override styles and behavior for that seat:

type HemicycleData<T> = T &
  ({ idx: number } | { rowIndex: number; seatIndex: number }) & {
    seatConfig?: SeatConfig<T>;
  };

Per-seat seatConfig is merged on top of the global seatConfig prop, so you only need to specify what differs.

Examples

Coloring seats by party

const members = [
  { idx: 0, party: "Left", color: "#e63946" },
  { idx: 1, party: "Center", color: "#457b9d" },
  // ...
];

<Hemicycle
  rows={7}
  totalSeats={577}
  data={members.map((m) => ({
    idx: m.idx,
    party: m.party,
    seatConfig: { color: m.color },
  }))}
/>;

Clickable seats with tooltips

<Hemicycle
  rows={5}
  totalSeats={100}
  data={seats.map((seat) => ({
    idx: seat.idx,
    seatConfig: {
      color: seat.partyColor,
      props: {
        onClick: () => setSelected(seat),
        style: { cursor: "pointer" },
      },
      wrapper: (content, data) => (
        <Tooltip key={data?.idx} label={data?.party}>
          {content}
        </Tooltip>
      ),
    },
  }))}
/>

Custom SVG container props

<Hemicycle
  rows={5}
  totalSeats={100}
  svgProps={{
    className: "my-chart",
    "aria-label": "Parliament seating chart",
    style: { maxWidth: "100%" },
  }}
/>

Typed seat data

type Member = {
  name: string;
  party: string;
};

const data: HemicycleData<Member>[] = members.map((m) => ({
  idx: m.seatNumber,
  name: m.name,
  party: m.party,
  seatConfig: { color: m.partyColor },
}));

<Hemicycle<Member> data={data} rows={7} totalSeats={577} />;

Seat Shapes

| Shape | Description | | -------- | ---------------------------------------------------------------- | | arc | Curved wedge following the concentric arc of the row (default) | | rect | Rectangle aligned to the seat's arc midpoint | | circle | Circle centered at the seat's midpoint |

Related

• @hemicycle/core — layout engine (geometry only, no rendering)
• @hemicycle/vanilla — framework-free SVG renderer

Contributing

Bug reports and pull requests are welcome on GitHub.

Support

• Issues: GitHub Issues
• Source: github.com/GabrielVidal1/hemicycle

Maintainer

Gabriel Vidal — [email protected]

License

MIT