Fast vertical QuickNav in Gecko-based textInfos

[mltony]

Link to issue number:

Closes #16382.

Summary of the issue:

Vertical navigation is too slow.

Description of user facing changes

N/A

Description of development approach

Retrieving x coordinate faster in Gecko textInfo by doing a direct IAccessible2 call - as opposed to creating an NVDAObject. According to my rough measurement, this speeds up vertical navigation about 10 times.

Testing strategy:

Tested on usecase provided in the issue above.

Known issues with pull request:

N/A

Code Review Checklist:

• Documentation:
  • Change log entry
  • User Documentation
  • Developer / Technical Documentation
  • Context sensitive help for GUI changes
• Testing:
  • Unit tests
  • System (end to end) tests
  • Manual testing
• UX of all users considered:
  • Speech
  • Braille
  • Low Vision
  • Different web browsers
  • Localization in other languages / culture than English
• API is compatible with existing add-ons.
• Security precautions taken.

[XLTechie]

Regarding the "time out on large documents by design" you spoke of in the issue: Can you make that timeout configurable? I do not suggest a UI element for it, but just a hidden config value so that it can be adjusted by anyone wishing to experiment.

[mltony]

I don't have any timeout logic in vertical navigation. What I mean by timeout is that some other part of NVDA - I suspect watchdog - prevents scripts from running for too long and interrupts them after 10 seconds. I am not familiar with that logic so don't know whether it's configurable.

[Adriani90]

How is this suposed to work in Chromium browsers when you use UiA? If this is not gonna work there, we should note that in the user guide or throw a message when people try to navigate vertically while using UIA.
I assume this PR will not have any effect on using vertical nav in MS Word or Outlook. Right? Anyway, I didn't notice performance issues in MS Office, it was only in browsers so far.

[mltony]

It still works in edge+UIA - I just tested. Just not as fast.

[seanbudd]

Thanks @mltony