Appendix H: Accessibility Support
This appendix is informative, not normative.
H.1 WAI Accessibility Guidelines
This appendix explains how accessibility guidelines
published by W3C's Web Accessibility Initiative (WAI) apply to
- The Web Content Accessibility Guidelines (WCAG) 2.0
explains how authors can create Web content that is
accessible to people with disabilities.
- The Authoring Tool Accessibility Guidelines 1.0
[ATAG] explains how
developers can design accessible authoring tools such as SVG
authoring tools. To conform to the
SVG specification, an SVG authoring tool must conform to
ATAG (priority 1). SVG support for element grouping and reuse is relevant to
designing accessible SVG authoring tools.
- The User Agent Accessibility Guidelines 1.0
[UAAG] explains how
developers can design accessible user agents such as
SVG-enabled browsers. To conform to the SVG specification, an
SVG user agent should conform to UAAG. SVG support for
scaling, style sheets, the DOM, and metadata are all relevant
to designing accessible SVG user agents.
The W3C Note Accessibility Features of SVG
explains in detail how the requirements of the three guidelines
apply to SVG.
H.2 SVG Content Accessibility Guidelines
This section explains briefly how authors can create
accessible SVG documents; it summarizes Accessibility Features of SVG
- Provide text equivalents for
- When the text content of a graphic (e.g., in a
‘text’ element) explains its function, no text
equivalent is required. Use the ‘title’ child element
to explain the function of ‘text’ elements whose meaning
is not clear from their text content.
- When a graphic does not include explanatory text
content, it requires a text equivalent. If the equivalent
is complex, use the ‘desc’ element, otherwise
use the ‘title’ child element.
- If a graphic is built from meaningful parts, build
the description from meaningful parts.
- Do not rely on color alone.
- Do not use color alone to convey information.
- Ensure adequate color contrast. Use style sheets so
that users who require certain color combinations may
apply them through user style sheets.
- Use markup and style sheets and do so
- Represent text as character data, not as images or
curves. Style text with fonts. Authors may describe their
own fonts in SVG.
- Separate structure from presentation.
- Use the ‘g’ element and rich
descriptions to structure SVG documents. Reuse named
- Publish highly-structured documents, not just
graphical representations. Documents that are rich in
structure may be rendered graphically, as speech, or as
braille. For example, express mathematical relationships
[MATHML] and use
SVG for explanatory graphics.
- Author documents that validate to the SVG
- Use style sheets to specify graphical and aural
- Use relative units in style sheets.
- Clarify natural language
- Use ‘xml:lang’ to identify the
natural language of content and changes in natural
- Ensure that dynamic content is
- Ensure that text equivalents for dynamic content are
updated when the dynamic content changes.
- Ensure that SVG documents are usable when scripts or
other programmatic objects are turned off or not