Re: Custom screen access


Travis Siegel
 

In general, if you have the source code for an application, (and with opensource, you do), there's no need to fiddle with screen reader built-in functions at all, just rewrite the actual application to use standard windows api calls, (instead of custom functionality) such as gui elements, buttons, and the like. This will automatically translate to better functionality in screen readers, because they're already built to watch the regular apis for information. I.E.
If the app is written in java, instead of drawing your text onto a canvas, like so many apps do, simply use a standard text control instead, it may take more work to make it look the way you want (which is why some folks use the graphical canvas), but it will automatically become more accessible without you having to do anything at all. in regards to the screen readers. Other languages have similar functionality issues. In general, using a nongraphical method to get the text to the screen, properly labeling graphical elements, and using standard windows controls instead of creating your own from scratch will make the applications completely accessible, with very few tweaks being necessary to complete any accessibility issues that may remain.
In general, the more custom gui elements you use, the less accessible your application becomes. Obviously, there's ways to get around this, but few (If any) developers know enough about accessibility out of the box to make those required modifications to custom elements so they work with screen readers. I don't know specifically what you're trying to fix, I've never heard of the application you're trying to fix, neither do I know what language it's written in, but most of the time, making an application more accessible doesn't require writing scripts or screen reader modules, simply make the application use standard windows controls at the source level, and most of those things will solve themselves.

On Sun, 21 Jun 2020, Christian Comaschi wrote:

Hello,
I'm asking a question that might be a little off topic because I'm not planning to develop anything for NVDA at the moment; but I'm working on an accessibility project and I'd like to know more about screen readers internals, and I think that someone here can help me find the info I need.
I'm writing custom code to improve the accessibility of an open source application (Plover), because common screen reader scripts and app modules alone don't allow me to bring it to the needed accessiblity requirements.
The problem is that at some point I need to read text from editable controls of any application in a "screen reader"-like manner, so I would like to know how screen readers can get the caret position and read the text of an editable control and the different approach of JAWS and NVDA.
I'm asking you the details of this functionality because I am trying to figure out if it could be a viable solution to read text from the screen in a "screen-reader like" manner with an approach that is valid for almost every application, or if it'stoo complex because it would require re-inventing a screen driver from scratch or re-inventing scripts for common application. In this latter case, I would consider a less stand-alone approach and make the application work in tandem with JAWS or NVDA.

After some analysis I have come to a conclusion and I would like to know if it's righgt:
- NVDA has no generic way to "read" the text given a screen position, but there are scripts for the most common applications that provide this information to the main module using the most proper technique for the single application (Win32 API, MSAA, UIA or other means);
- JAWS seems to have generic functions such as "SayLine", "SayRow" or "SaySentence" that work for most of the applications because of its video intercept driver.

As a first try, I wrote some small scripts to use just UIA to read the text and caret position inside Notepad or Winword, but it didn't work; I also tried to use the inspect tool from Microsoft, meant to analyze the windows of any application to get accessibility info, but even that tool wasn't able to get the caret position inside the edit windows.
Am I missing something or is it really that complex?
Thanks in advance
Best,
Christian









Join nvda-devel@groups.io to automatically receive all group messages.