[Accessibility-ia2] next changes to IAccessible2
jamie at nvaccess.org
Thu Jun 9 04:08:54 PDT 2011
While I recognise the importance of media accessibility, I think special
purpose interfaces are generally best avoided and so extreme caution
needs to be exercised when considering them. I think we need to clearly
determine the use cases for each interface and part thereof. My initial
feeling is that most of this either does not belong in an accessibility
API or can be done in a far more general way.
I don't see the need for a special interface to control media. The media
playback controls can already be exposed as normal controls to ATs (e.g.
buttons, sliders, etc.), just as they are now, with the application
providing keyboard shortcuts as appropriate. Selection and toggling of
media tracks can (and should) similarly be handled by the application
using a standard UI.
Output of text cues can be generalised and handled using live regions.
The only piece remaining is pausing of audio while the AT reports the
cue to the user if that reporting would overlap with another cue. This
really does venture outside the scope of current accessibility APIs, as
ATs don't generally change application behaviour, but rather allow
exposure and interaction with UI. I don't really have a good solution
for this yet. However, the proposed solution has several problems:
1. The event could be picked up by multiple ATs, but not all of them may
want the pause on exit behaviour. An event shouldn't generally change
application behaviour just because an app picked it up; it should be
passive. Also, keep in mind that many a11y clients register for all
events, even if they don't use them all.
2. What if a user is using multiple ATs; e.g. screen reader and
magnifier? One might issue a request to fetch the next cue, but another
might not be finished outputting it yet.
On 8/06/2011 7:46 PM, Alexander Surkov wrote:
> Based on my talk with Silvia couple days ago I think I can suggest API
> for your consideration -
> Thank you.
Vice President, Developer
NV Access Inc, ABN 61773362390
Email: jamie at nvaccess.org
Web site: http://www.nvaccess.org/
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