Add Braille Viewer to NVDA

[LeonarddeR]

@feerrenrut created a handy tool to view braille on screen. Especially for sighted testers, it would be ideal if this would be available in core.

Note that braille.BrailleBuffer now has a windowRawText auto property which can be used to get the raw text for the current window. It should also be made sure that the braille viewer does not conflict with the speech viewer. May be even tie them together?

[feerrenrut]

@LeonarddeR this tool came from @jcsteh originally. I have been looking at how to integrate this into core. I agree that it would be quite handy!

A couple of points:

• I would suggest braille viewer it is kept independent from speech viewer
• Like speech viewer it should be enabled through the tools menu
• A real braille display should be able to be used at the same time
  • For simplicity (of displaying, and navigating etc), I would suggest that the braille viewer tool adapts to take on the same number of cells as the active physical braille display.
• The braille viewer should show the raw text as well as the dots.

[LeonarddeR]

@feerrenrut commented on 22 nov. 2017 08:19 CET:

• Like speech viewer it should be enabled through the tools menu

Seems like a completely new implementation. How about a toggle to switch between speech and braille in the speech viewer?

• For simplicity (of displaying, and navigating etc), I would suggest that the braille viewer tool adapts to take on the same number of cells as the active physical braille display.

I agree, but that might add some complexity in case of lengthy displays, in which case braille dots and/or text may not fit on one line of the screen.

[feerrenrut]

@LeonarddeR I have pushed a proof of concept for the braille viewer tool. This is far from finished, although quite functional. See branch i7788-integrateBrailleViewer and comparison with master

[feerrenrut]

How about a toggle to switch between speech and braille in the speech viewer?

I for one would like to be able to view them both at the same time, often I want to compare the output.

I agree, but that might add some complexity in case of lengthy displays, in which case braille dots and/or text may not fit on one line of the screen.

This is true, however, matching the number of cells simplifies the implementation within braille.py. If it proved to be a problem for people, I think we could handle this on the GUI side.

[LeonarddeR]

Looks quite good, except for that I'm a bit worried about compatibility with braille support in the NVDA Remote add-on, which also magically changes braille.handler.displaySize. This is likely to cause issues when a remote connection is established with someone having a shorter braille display than the current braille display width. Also, I belief that in the current situation, NVDA Remote will simply disable the braille handler as soon as a user without a braille display disconnects from a system with a braille display, even though the viewer is active.

[feerrenrut]

Ok, I'll have to look at how NVDA Remote interacts here.

How are these issues currently handled when physical braille displays are present?

[DrSooom]

In my opinion the braille viewer window should contain the following:

1. First line in plain text mode (Consolas). The text on the braille display can be read here as "normal" text. The Braille-Cursor is shown as an underlined letter. And the underline should blink depending on the time set up in the braille settings window.
2. Second line in braille dots mode (Consolas, but using U+2800 to U+28FF for the unicode braille characters). The Braille-Cursor is shown as set up in the braille settings dialog.
3. A Button "scroll backwards" on the left bottom corner.
4. Followed by the checkbox "Mirroring current connected braille display". Default value is "false". And "false" will enable the following.
5. Combobox "Length" which contains the following firm values: 12, 14, 16, 18, 20, 24, 32, 40, 42, 44, 60, 64, 80, 84 and 88. This setting offers the developer to test the braille output without having braille display of different lengths.
6. And of course the button "scroll forward" in the right bottom corner.
7. And last but not least: Clicking on an letter in the plain text line as well as on an unicode braille character in the second with a left mouse click line will force to emulate a (braille) routing key press. And a right click will force to the 2nd routing function.
8. Well, and the speaker and braille viewer should be of course two different window because I don't think the a developer needs and wants to have always both output at the same time.

[lukaszgo1]

Hi @feerrenrut,
I've tested your code and it is working well except one small thing

STR

1. enable braille viewer or switch to physical braille display
2. open python console and type the following
   import braille
   braille.handler.message('')

expected

The braille display or braille viewer window should be empty for the timeout configured in NVDA settings.

actual

File "braille.pyc", line 1731, in message
File "braille.pyc", line 1685, in update
File "baseObject.pyc", line 21, in get
File "braille.pyc", line 1332, in _get_windowRawText
File "braille.pyc", line 1174, in bufferPositionsToRawText
IndexError: list index out of range

[feerrenrut]

It's taken me a while to come back to this.
Thanks @lukaszgo1, I have fixed this issue now.
@DrSooom these would be nice to have, however first I would like to get this integrated in it's most basic form. Further requests should be opened in new issues.

[feerrenrut]

Fixed with commit 1863d23 via PR #10173