# Lightbox

> Modal image viewer with keyboard navigation across a gallery of images.

- Status: alpha
- Group: media
- Page: https://www.digitaltableteur.com/design-system/components/lightbox
- Contract: https://www.digitaltableteur.com/contracts/v1/Lightbox.contract.json

## When to use

Modal image viewer with keyboard navigation across a gallery of images.

## When not to use

- Do not open a Lightbox from inside a Modal when the images can live on the page; it works (the Lightbox becomes the topmost focus trap and one Escape closes only the Lightbox) but two stacked dialogs are heavier than one.
- Do not use it for non-image content. It is sized and captioned for images; use `Modal` for arbitrary content.

## Look-alikes

- Modal: Do not use it for non-image content. It is sized and captioned for images; use `Modal` for arbitrary content.

## Props

| Prop | Type | Default | Description | Required |
| --- | --- | --- | --- | --- |
| `images` | `LightboxImage[]` | none | No description in the contract. | Yes |
| `initialIndex` | `number` | `0` | No description in the contract. | No |
| `open` | `boolean` | `false` | No description in the contract. | No |
| `onOpenChange` | `(open: boolean) => void` | none | No description in the contract. | No |

## Variants

No variant dimensions and no props with a fixed set of values.

## Invalid combinations

The contract records no invalid combinations.

## Keyboard

| Key | Behaviour |
| --- | --- |
| Escape | Closes the lightbox. |
| ArrowRight | Advances to the next image. |
| ArrowLeft | Returns to the previous image. |
| Tab | Cycles through the panel buttons and is trapped inside the dialog. |
| Shift+Tab | Wraps backwards. |

## Rules

Every item under When not to use is a MUST NOT. MUST and SHOULD follow RFC 2119.

| Level | Rule | How it is checked |
| --- | --- | --- |
| MUST | ARIA: Role=dialog with aria-modal=true on the panel. | Not yet verified: no evidence record. WCAG 4.1.2. |
| MUST | ARIA: Aria-label is the current image's alt, or "Image gallery" when alt is empty; position is announced by the counter's polite live region, not the name. | Not yet verified: no evidence record. WCAG 4.1.2. |
| MUST | ARIA: Focus moves to the close button on open and returns to the previously focused element on close. | Not yet verified: no evidence record. WCAG 4.1.2. |
| MUST | ARIA: While open, every page region outside the dialog (header, main, footer and sibling layers) is inert through the shared focus trap, so aria-modal=true matches what is reachable. | Not yet verified: no evidence record. WCAG 4.1.2. |
| MUST | ARIA: One Escape press calls onOpenChange(false) once; Escape and the arrow keys are ignored while a layer opened above the Lightbox is active. | Not yet verified: no evidence record. WCAG 4.1.2. |
| MUST | ARIA: Re-rendering the parent with a new onOpenChange function does not move focus or toggle inert. | Not yet verified: no evidence record. WCAG 4.1.2. |
| MUST | Required stories produce no axe violations at the configured severity. | Automated by `npm run test:stories:matrix:ci`. WCAG 2.5.8. |
| MUST | The accessibility tree (role, name, state) matches the committed snapshot for every required story. | Automated by `npm run test:stories:matrix:ci`. WCAG 1.3.1, 4.1.2. |
| MUST | The component remains legible and operable under a real browser forced-colors: active pass. | Automated by `npm run test:stories:hc`. |
| MUST | Positional, scale, and opacity motion is suppressed under prefers-reduced-motion. | Manual review, last on 2026-11-04. WCAG 2.2.2, 2.3.3. |
| MUST | Every documented keyboard interaction works as specified. | Manual review, last on 2026-11-04. WCAG 2.1.1, 2.1.2. |

## Install and import

- In-repo only. Lightbox is not exported from `@digitaltableteur/react`, so there is no public import path.
- Alpha components are internal and never exported.

## Links

- Machine-readable contract (Design System Contract 1.0): https://www.digitaltableteur.com/contracts/v1/Lightbox.contract.json
- Markdown version of this page: https://www.digitaltableteur.com/design-system/components/lightbox.md
- Component index as JSON: https://www.digitaltableteur.com/design-system/components.json
- All components: https://www.digitaltableteur.com/design-system/components
- Source: The implementation lives in a private repository. This page, its Markdown twin and the contract are generated from it at build time and are the public source of truth.