Pmndrs.docs

Introduction

Quick start about how to make your WebGL accessible with @react-three/a11y and react-three-fiber

@react-three/a11y brings accessibility to webGL with easy-to-use react-three-fiber components:

  • Focus and focus indication
  • Tab index and keyboard navigation
  • Screen reader support and alt-text
  • Roles and cursor shapes
  • Descriptive links

You can try a live demo here. Open it with your favourite assistive tech to test it out !

npm install @react-three/a11y

Quick overview to get started

The A11yAnnouncer component

First, place the A11yAnnouncer component next to the R3F Canvas component. This componant is critical since it manage some screen-reader features.

import { Canvas } from '@react-three/fiber'
import { A11yAnnouncer } from '@react-three/a11y'

function App() {
  return (
    <>
      <Canvas />
      <A11yAnnouncer />
    </>
  )
}

Then wrap components you want to make accessible with the A11y component

To add accessibility features to your scene you'll have to wrap components you want to make focusable with the A11y component:

import { A11y } from '@react-three/a11y'
[...]
<A11y>
  <MyComponent />
</A11y>

MyComponent can now receive focus. More accurately, the emulated "focus" will be handled at the A11y components which acts as a provider for children to access its state. But even if objects are focusable, nothing will be displayed or shown by default.

Call function on focus

The focusCall prop of A11y will be called each time this component receives focus (usually through tab navigation).

<A11y role="content" focusCall={()=> console.log("in focus")} ... />

Call function on click / keyboard Click

The actionCall prop of A11y will be called each time this component gets clicked, focused, keyboard activated etc.

<A11y role="button" actionCall={()=> console.log("clicked")} ... />

Provide a description of the currently focused / hovered element

When using the description prop in combination with the role prop, the A11y component will provide a description to the screen reader users on focus/hover. Optionally, you can also show the description to the user on hover by setting showAltText={true}.

// Reads "A rotating red square" to screen readers on focus / hover while also showing it on mouseover
<A11y role="content" description="A rotating red square" showAltText ... />
// Reads "Button, open menu + (description on how to activate depending on the screen reader)" to screen readers on focus / hover
<A11y role="button" description="open menu" actionCall={()=>{someFunction()}} ... />

The four roles of the A11y component

Like in HTML, you can focus different kind of elements and expect different things depending on what you're focusing.

Content

<A11y role="content" ... />

Uses the default cursor. This role is meant to provide information to screen readers or to serve as a step for a user to navigate your site using Tab for instance. It's not meant to trigger anything on click or to be activable with the Keyboard. Therefore it won't show a pointer cursor on hover.

Read more about role content

Button

<A11y
  role="button"
  description="Send email"
  activationMsg="Sending email" ... />

Uses the pointer cursor. Special attributes: activationMsg.

This role is meant to emulate the behaviour of a button or a togglable button. It will display a cursor pointer when your cursor is over the linked 3D object. It will call a function on click but also on any kind of action that would trigger a focused button (Enter, Double-Tap, ...). It is also actionnable by user using a screen reader.

Read more about role button

ToggleButton

By using the role togglebutton, you'll emulate a button with two state that will have the aria-pressed attribute. You'll then be able to use the deactivationMsg property in addition to the usual description and activationMsg properties.

<A11y
  role="togglebutton"
  description="Dark theme "
  activationMsg="Switched to dark theme"
  deactivationMsg="Switched to light theme" ... />

Special attributes: deactivationMsg

Read more about role ToggleButton

Link

<A11y role="link" href="https://url.com" ... />

Uses the pointer cursor. Special attributes: href.

This role is meant to emulate the behaviour of a regular html link. It should be used in combination with something that will trigger navigation on click.

- Don't forget to provide the href attribute as it is required for screen readers to read it correctly! - It will have no effect on the navigation, it's just used as information

Read more about role link

Screen Reader Support

In order to provide informations to screen reader users and use this package at its full potential, fill the description prop of all your A11y components and use the appropriate role prop on each of them.

Use of section

For screen readears, it might be useful to provide additionnal information on how to use some unconventional UI. You can do it by wrapping the concerned part of your code relative to this UI in the A11ySection like so.

<A11ySection
  label="Shape carousel"
  description="This carousel contains 5 shapes. Use the Previous and Next buttons to cycle through all the shapes."
>
  [...]
</A11ySection>

Access user preferences

The A11yUserPreferences component is available in order to access user preferences such as

  • prefers-reduced-motion
  • prefers-color-scheme

Take a look at the A11yUserPreferences page or the demo to see it in action and how to use it. The demo will adapt to your system preferences.

Additionals Features

Use a custom tabindex with for your A11y components by providing a number to the tabIndex attribute

<A11y tabIndex={-1} ... />
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Avoid using tabindex values greater than 0. Doing so makes it difficult for people who rely on assistive technology to navigate and operate page content. Instead, write the document with the elements in a logical sequence.
More about the use of tabIndex on developer.mozilla.org