Accessibility notes

These are DRAFT notes on what CSS classes, PHP functions and the so on have been added to Moodle 1.6 onwards to aid accessibility. They can be seen as design patterns, techniques, guidelines, and perhaps best practice(?) Based on a workshop at Moodlemoot 2007, Canada Lots for me to add/edit! Comments welcome! Nick Freear 11:38, 28 August 2007 (CDT)

Assistive technology

Technology to enable those with disabilities to use a computer can be categorised in terms of their distance from the user. For example:

• Physical layer: specialist pointing devices, mice, joy-sticks, keyboards.
• Operating system layer: Mac Voiceover, Windows Narrator ...
• System specialisation layer: technology not part of the OS that tries to work with all software tools.
  • Screen magnification.
  • Screen readers: JAWS, Window-Eyes, Thunder/WebbIE (speech or braille).
  • Speech recognition: Dragon Naturally Speaking ...
• Software tool layer: audio browsers, plug-ins for Web browsers, word processors.
• Application layer: technology integrated in a web site, eg. Browsealoud, style sheet switching/ high-contrast, font size (bad?); ?
• Document layer: tagged PDFs, well-structured semantic PDFs, Word documents, HTML documents.

What JAWS says

Examples of what the JAWS screen reader verbalises for good and bad markup.

Accessibility design patterns

Pattern 1: unlist, inline-list

Cascading style sheet (CSS) classes to remove default list-styles from HTML lists. Class inline-list also makes a list horizontal (at present only in side blocks).

Difficulty: easy I hope. Please use!
Available: ? Moodle 1.8 December 2006 (MDL-6838, nested lists are safe).
Definition: theme/standard/styles_layout.css

.unlist, .inline-list {
  list-style: none;
  padding: 0;
  margin: 0;
}
.sideblock .content .inline-list li {
  display: inline;
}

Use Count: 5+ (12 including deprecated list)
Example: blocks/../block_blog_tags.php

<ul class="inline-list">
  <li><a .. class=" s20">Accessibility</a></li>
  <li><a .. class=" s10">Test</a></li> 
</ul>

Pattern 2: accesshide

CSS class for text to be 'seen' by screen readers but not visual users.

Text classed as accesshide provides context for a non-sighted user, where the context or meaning would otherwise be clear from formatting, for example coloured text, or a silent character (TODO: link). The example below shows how additional text is provided to differentiate today from the other days in the Moodle calendar - visual differentiation is provided in the standard theme by a black border, and the accesshide text is duplicated, in this case using Javascript (TODO: modify code! Javascript should use the title attribute.)

Please, use cautiously — most necessary uses have already been identified.

• Difficulty: tricky — please put the same text in an adjacent/parent title.
• Available: Moodle 1.6 March 2006 (30-May-06: MDL-5628 <acronym title="Internet Explorer">IE</acronym>6 Farsi <acronym title="Right-to-left">RTL </acronym>language)
• Definition: theme/standard/styles_layout.css

.accesshide {
  position: absolute;
  top: -1000px;
}

• Use Count: 29 !
  
• Example: calendar/lib.php

...
<td class="day">26</td>
<td class="day today">
  <span class="accesshide">Today Friday, 27 April </span>
  <a onmouseover="return overlib(.. 'Today Friday, 27 April')" ..>27</a>
</td>
<td class="weekend day">28</td>
...

Pattern 3: left, right arrows

PHP variables holding 'silent' representations of right and left arrows (example ► ►), to avoid misuse of characters including "greater than" >, "right angle quote" ». The variables are initialised by the function weblib.php: check_theme_arrows, unless they have first been defined in the theme config.php.

• Difficulty: medium. Careful with fonts.
  
• Available: Moodle 1.7
• Functions in lib/weblib.php

function check_theme_arrows()
function link_arrow_right($text, $url='', $accesshide=false, $addclass='')
function link_arrow_left($text, $url='', $accesshide=false, $addclass='')
function get_separator()

$THEME->rarrow
$THEME->larrow 

• Associated CSS in theme/standard/styles_fonts.css

.arrow, .arrow_button input {
  font-family: Arial,Helvetica,Courier,'Arial Unicode MS',sans-serif;
}

• Use count: ?
• Example PHP: weblib.php function print_navigation - breadcrumb trail.
• Also: Weekscss course format, Moodleforms .