The perceivable principle
This page is for everyone on a public website team. WCAG 2.2 groups its success criteria under four principles; the first says that information and interface components must be presentable to users in ways they can perceive (https://www.w3.org/TR/WCAG22/). Below, the four guidelines of this principle, with what each role does in an Exponential project and what the administration already does.
Contents
1.1 Text alternatives
| Role | Does |
|---|---|
| Editors | fill Alternative image text for every informative image; describe charts in text |
| Administrators | switch on "Alternative text is required" on image attributes of the classes editors use |
| Designers | decide how decorative images are marked; icon-only links and buttons get a name |
| Developers | override the image template if decorative images must render alt="" (the standard template falls back to the object name) |
Admin4: every form control has an accessible name (AdminFormLabelsTest.php). See "Alternative text for images".
1.2 Time-based media
| Role | Does |
|---|---|
| Editors | captions for video with speech, transcripts for audio and video, no autoplay |
| Developers | add caption tracks in the media template if you need them (the standard template writes none) |
See "Captions and media".
1.3 Adaptable
| Role | Does |
|---|---|
| Editors | real headings in order, lists, tables with header cells and captions |
| Designers | reading order equals visual order; no meaning by position alone |
| Developers | landmarks, one h1, scope on header cells, labeled form fields, autocomplete on personal fields |
Admin4: landmarks, skip link, scope="col", required fields marked for screen readers, direction for right-to-left
languages (AdminLandmarksTest.php, AdminRightToLeftTest.php).
1.4 Distinguishable
| Role | Does |
|---|---|
| Editors | never color alone ("the fields in red"); no images of text |
| Designers | text 4.5:1, controls and focus 3:1, links distinguishable, reflow at 320 px, 200% zoom, text spacing |
| Developers | tokens, no fixed heights that clip text, no horizontal page scrolling, respect user settings |
Admin4: contrast tokens checked in light and dark mode, notices with icons as well as colors, responsive widths, forced
colors and reduced motion (AdminTokenContrastTest.php, AdminNoticesTest.php, AdminResponsiveTest.php).
Related pages
- Mapping WCAG 2.2 AA to Exponential
- Color and contrast in your theme
- Alternative text for images
- Free documentation: this page is free to copy, translate and improve under the GNU FDL 1.3.
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