[nvda] Re: Audacity problem

Well the short answer is, MSAA is a set of functions that microsoft created to expose certain elements of the information that is sent through the operating system so that assistive programs like screen readers can understand what control they are looking at. Unfortunately, Microsoft did not put as many functions into MSAA as they should have. Now because of this, the larger screen readers like Jaws and Window Eyes decided to bypass or build on the MSAA information by tapping into the video card information as it is written to the screen by creating their own virtual video drivers. Microsoft at the time when this was done did not recommend that they did this but because it did make up for the shortfalls in MSAA the system worked. Now however, the big screen readers are having to redesign their strategy because Vista changes the way video cards access information. MSAA however is still backwards compatible to Microsoft's new accessibility model called UIA. There is one other accessibility model that deserves mention and that is IAccessible2. What IAccessible2 does is it builds off of the MSAA model by adding more functions and objects that a screen reader can recognize. The problem with IAccessible2 though is that it is not very widely supported by applications yet. Mozilla Firefox however is beginning to support IAccessible 2 in its source code. NVDA does also use that IAccessible2 information when reading information in Firefox. I am not completely certain how extensive the support is in Firefox 2 but Firefox 3 is supposed to provide better support for it. But to sum up, all 3 of those accessibility models send text elements to a screen reader. In alot of cases it does depend on how well the programmer of the application allows MSAA to expose this information to the screen reader. I am not certain of this but it does seem like in the case of the Audasity radio buttons they simply forgot to give them an MSAA compatible label. I hope my explaination helped you to understand it a little bit better. ----- Original Message ----- From: "Gene" <gsasner@xxxxxxxxx> 
To: <nvda@xxxxxxxxxxxxx>
Sent: Wednesday, September 26, 2007 11:54 AM
Subject: [nvda] Re: Audacity problem
I don't know if this question can be answered properly for someone without a technical background like me. However, this thread has gotten me curious. While I knew in the past that lack of video hooks imposes limitations in what screen-readers can do, I didn't know much about what these are. My question is, why can a screen-reader without video hooks see text in programs like Notepad, Wordpad, etc. and yet not see text as displayed by Audacity as we have been discussing. There must be some very different way in which the text is displayed.
Another question is whether it makes sense for me to report the kind of problem I found with Audacity if I find something similar elsewhere. Is this just unnecessary information since the lack of video hooks is, evidently likely, the explanation for such problems or is it better to report further cases so they can be definitely determined to be video hook limitations or something else. 

Gene
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Report bugs or make feature requests at:
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