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Slider accessibility #2777

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157 changes: 73 additions & 84 deletions src/pages/components/slider/accessibility.mdx
Original file line number Diff line number Diff line change
Expand Up @@ -6,99 +6,88 @@ description:
tabs: ['Usage', 'Style', 'Code', 'Accessibility']
---

import {
StructuredListWrapper,
StructuredListHead,
StructuredListBody,
StructuredListRow,
StructuredListInput,
StructuredListCell,
OrderedList,
ListItem,
} from 'carbon-components-react';
import localVideo from './videos/slider.mp4';
import localPoster from './images/slider-accessibility-3.png';

<PageDescription>

The slider React Carbon component has been tested against the latest
[W3C Web Content Accessibility Guidelines (WCAG) 2.1 Level A and AA success criteria](https://www.w3.org/TR/WCAG21/)
and violations have been identified as high priority issues. This document will
be updated when these accessibility issues are resolved.
No accessibility annotations are needed for sliders, but keep these
considerations in mind if you are modifying Carbon or creating a custom
component.

</PageDescription>

<AnchorLinks>
<AnchorLink>Accessibility considerations</AnchorLink>
<AnchorLink>Resources</AnchorLink>
<AnchorLink>Accessibility testing</AnchorLink>
<AnchorLink>What Carbon provides</AnchorLink>
<AnchorLink>Development considerations</AnchorLink>
</AnchorLinks>

## Accessibility considerations

1. Labels should be clear and concise.

## Resources

- [W3C WAI-ARIA Authoring Practices Slider Design Pattern](https://www.w3.org/TR/wai-aria-practices/#slider)
covers the usage of ARIA names, state and roles, as well as the expected
keyboard interactions.
- [IBM Accessibility Requirements](https://www.ibm.com/able/requirements/requirements/):
- [1.3.1 Info and Relationships](https://www.ibm.com/able/requirements/requirements/#1_3_1)
(WCAG Success Criteria
[1.3.1](https://www.w3.org/WAI/WCAG21/Understanding/info-and-relationships))
- [1.3.2 Meaningful Sequence](https://www.ibm.com/able/requirements/requirements/#1_3_2)
(WCAG Success Criteria
[1.3.2](https://www.w3.org/WAI/WCAG21/Understanding/meaningful-sequence))
- [2.1.1 Keyboard](https://www.ibm.com/able/requirements/requirements/#2_1_1)
(WCAG Success Criteria
[2.1.1](https://www.w3.org/WAI/WCAG21/Understanding/keyboard))
- [2.4.3 Focus Order](https://www.ibm.com/able/requirements/requirements/#2_4_3)
(WCAG Success Criteria
[2.4.3](https://www.w3.org/WAI/WCAG21/Understanding/focus-order))
- [2.4.6 Headings and Labels](https://www.ibm.com/able/requirements/requirements/#2_4_6)
(WCAG Success Criteria
[2.4.6](https://www.w3.org/WAI/WCAG21/Understanding/headings-and-labels))
- [2.4.7 Focus Visible](https://www.ibm.com/able/requirements/requirements/#2_4_7)
(WCAG Success Criteria
[2.4.7](https://www.w3.org/WAI/WCAG21/Understanding/focus-visible))
- [4.1.2 Name, Role, Value](https://www.ibm.com/able/requirements/requirements/#4_1_2)
(WCAG Success Criteria
[4.1.2](https://www.w3.org/TR/UNDERSTANDING-WCAG20/ensure-compat-rsv.html))

## Accessibility testing

Accessibility issues are tracked in the
[Carbon Component GitHub repository](https://github.com/carbon-design-system/carbon/issues?q=is%3Aopen+label%3A%22type%3A+a11y+%E2%99%BF%22+label%3A%22component%3A+slider%22+).

### Automated test
## What Carbon provides

Carbon bakes keyboard operation into its components, improving the experience of
blind users and others who operate via the keyboard. Carbon incorporates many
other accessibility considerations, some of which are described below.

### Keyboard interactions

Tab order goes from slider to text input. Arrow keys are used to change the
slider value. `Shift`+arrow changes the slider value by a larger increment (such
as by 10 instead of 1). Users can also directly enter a value in the input.

<Row>
<Column colLg={8}>

![example of slider keyboard interaction](images/slider-accessibility-1.png)

<Caption>
Both the slider and input are in the tab order and keyboard operable.
</Caption>

</Column>
</Row>

### Labeling and updates

<Row>
<Column colLg={8}>

![slider label is connected to slider control and text input](images/slider-accessibility-2.png)

<Caption>
The slider label is programmatically associated with both the slider and
input.
</Caption>

</Column>
</Row>

<Row>
<Column noGutterSm>
<StructuredListWrapper>
<StructuredListHead>
<StructuredListRow head>
<StructuredListCell head>
Automated test environment
</StructuredListCell>
<StructuredListCell head>Results</StructuredListCell>
</StructuredListRow>
</StructuredListHead>
<StructuredListBody>
<StructuredListRow>
<StructuredListCell>
- macOS Mojave version 10.14.6 with VoiceOver
<br />
- Chrome version 77.0.3865.90
<br />
- Dynamic Assessment Plugin (DAP) version 1.8.0.0 - IBM
Accessibility WCAG 2.1 Sept. 2019 Ruleset
<br />- Carbon React version 7.7.1
</StructuredListCell>
<StructuredListCell>
<strong>DAP test:</strong>
<br />- No violations
</StructuredListCell>
</StructuredListRow>
</StructuredListBody>
</StructuredListWrapper>
</Column>
<Column colLg={8}>

<Video
src={localVideo}
poster={localPoster}
aria-label="pointer clicks on slider range and input updates to 80. input value changes to 75 and slider repositions to match"
/>

<Caption>
The input value and slider position are in sync. An update to either causes
the other to update.
</Caption>

</Column>
</Row>

## Development considerations

Keep these considerations in mind if you are modifying Carbon or creating a
custom component:

- The `step` value determines the change increment when moving the slider,
either by pointer or keyboard. A value of `"1"` is recommended.
- The `stepMultiplier` determines the value change when the keyboard is used to
alter the slider by pressing `Shift`+ Arrow key. A tenth of the total range is
recommended as a value, such as `"10"` in a 0-100 slider.
- See the
[ARIA authoring practices](https://www.w3.org/TR/wai-aria-practices-1.2/#slider)
for more considerations.
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