Accessibility of Rich Media – Part 3 Flash Accessibility

Follow-up to Accessibility of Rich Media – Part 2 PDF Accessibility from Sara's Mindbloggeld

Unless carefully developed Flash presents accessibility barriers for many people with physical disabilities, however it is important to realise it is a medium that can enhance accessibility for many.

Because of the MSAA approach (a database that feeds out flash content to assistive technologies – flashes accessibility implementation) Flash accessibility features are ONLY available to the player that runs in Internet Explorer on Windows. However accessible your Flash content is it will not work with a screen reader on the Mac or Linux platforms

Flash 8 makes it easier to set the reading order in a movie because you now only need to set specific values for relevant objects – you don’t need to set an order for all of the flash elements on the page as you do in Flash 7

NOTE: If you use static text anywhere in a movie it destroys your reading order and sets it back to the default top left to right and then down the page – testing is very important!

Having heard this I do wonder whether static text could be avoided completely in favour of dynamic or input text.

Setting accessibility features via the accessibility panel is still the means of setting accessibility features, or accProps if coded directly through ActionScript. For a full guide to they recommended Adobe Best Practices document. Had a quick look at this link just now and it looked pretty good there is a table that covers the accessibility of 22 components within flex.

Web Content Accessibility Guidelines 2.0 WCAG try to encompass guidance for Flash and PDF but are still draft.

Accessibility Tips:

• Ensure good colour contrast
• Don’t convey info with colour only
• Make use of ‘anti-alias for readability’ on text
• keep a consistent layout to make life easier for magnification users and others who take longer to process information – apply good usability principles and this will benefit all users
• Ensure any sound can be quickly switched off
• Make sure buttons and controls are properly labelled
• Be careful with looping animations, these may cause a screen reader to return to the top of the page every time the movie refreshes
• make sure the reading order is logical
• consider that some users may not have full mobility so drag and drop becomes an issue, click and drop is easier for them
• can the application be navigated via the keyboard only? – voice recognition users have to fall back to a system called mousegrid where they move elements around a numbered grid
• provide captions or sign language (signers use a different vocabulary than spoken english so signing is better than captioning)

Something that occurred to me during the course was the principle of not getting in the users way. So if you can use an external stylesheet for as much styling of fonts, colours etc. as possible then this could be overridden by the screen readers preferences or accessibility stylesheets which would be much better. Particularly given that different options work for different disabilities one set of colours does not work for all dyslexics for instance.

Accessibility Testing

• Check is whether the application can be used via the keyboard only
• Check audio can be turned on and off on each page
• There is good contrast between text and graphics
• The navigation is easy to use
• An intermediate level of checking can be achieved by using a screen reader yourself
• The best testing is via feedback from both a novice and competent screen reader user

Links:

http://www.signacademy.org.uk/
Web Accessibility Toolbar

Sara Lever : 24 Jul 2007 14:38 |  Tags: Ajax Flash Multimedia Pdfs Video |  Comments (0) |  Trackbacks (1) |  Report a problem