Development: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:
- Specialist pointing devices, keyboards.
- Screen magnification.
- Screen readers: JAWS, Window-Eyes, Thunder/WebbIE (speech or braille).
- Speech recognition: Dragon Naturally Speaking ...
- Operating system built-in: Mac Voiceover, Windows Narrator ...
- Web site built-in: Browsealoud, style sheet switching/ high-contrast, font size (bad?) ...
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 .