Say all does not turn the page properly in bookworm

[Mohamed00]

Steps to reproduce:

1. Download Bookworm, a book reader. A build can be found here. https://ci.appveyor.com/api/buildjobs/kffqbo4qru8pok39/artifacts/scripts%2FBookworm-2022.1b1-x64-portable.zip. Go into general preferences by pressing control+shift+p, and make sure the Try to support the screen reader's continuous reading mode by automatically turning pages (may not work in some cases) option is enabled.
2. Open a PDF file and read it using say all. Example: https://www.dropbox.com/s/rlq00oplvkfzfl2/DoubleTalk%20RC8660%20Chipset%20Manual.pdf?dl=1.

Actual behavior:

Say all doesn't turn the page after the end of it is reached. You will notice that it will stop reading around the end of page 1.

Expected behavior:

Say all should be able to continuously turn the page.

NVDA logs, crash dumps and other attachments:

System configuration

NVDA installed/portable/running from source:

Installed

NVDA version:

alpha-25928,3894e25f

Windows version:

Windows 11, Version 22H2 (OS Build 25158.1000).

Name and version of other software in use when reproducing the issue:

Bookworm 2022.1b1.

Other information about your system:

N/A

Other questions

Does the issue still occur after restarting your computer?

Yes.

Have you tried any other versions of NVDA? If so, please report their behaviors.

Yes, NVDA snapshot alpha-25824,9172c09a and below work normally.

If NVDA add-ons are disabled, is your problem still occurring?

Yes.

Does the issue still occur after you run the COM Registration Fixing Tool in NVDA's tools menu?

Yes.

[lukaszgo1]

Possibly caused by #13670 cc @mltony

[seanbudd]

I can reproduce this.
It appears that the next page is reached successfully, however the cursor remains at the end of the page, so all speech on the page is skipped.

[mltony]

I will take a look this weekend.

[seanbudd]

Likely related: #13420

The title says "some applications" but this is just bookworm right?

[Mohamed00]

It seems so, but I think it's an NVDA issue. The debug log repeatedly mentions say all:line reached callbacks when it fails to turn the page. Example: IO - speech.speech.speak (04:59:21.177) - MainThread (19208):
Speaking [CallbackCommand(name=say-all:lineReached), CallbackCommand(name=say-all:lineReached), CallbackCommand(name=say-all:lineReached), CallbackCommand(name=say-all:lineReached), CallbackCommand(name=say-all:lineReached), CallbackCommand(name=say-all:lineReached), CallbackCommand(name=say-all:lineReached), CallbackCommand(name=say-all:lineReached), CallbackCommand(name=say-all:lineReached), CallbackCommand(name=say-all:lineReached)]
IO - speech.speech.speak (04:59:21.348) - MainThread (19208):
Speaking [CallbackCommand(name=say-all:lineReached), CallbackCommand(name=say-all:lineReached), CallbackCommand(name=say-all:lineReached), CallbackCommand(name=say-all:lineReached), CallbackCommand(name=say-all:lineReached), CallbackCommand(name=say-all:lineReached), CallbackCommand(name=say-all:lineReached), CallbackCommand(name=say-all:lineReached), CallbackCommand(name=say-all:lineReached), CallbackCommand(name=say-all:lineReached)]
DEBUG - speech.sayAll._TextReader.nextLine (04:59:21.583) - MainThread (19208):
no self.reader.

[mltony]

I was overwhelmed by urgent issues at work, so didn't have time to fix this yet. Will try to find time in the next couple of weeks.

[mltony]

I spent some time looking into this issue. I haven't figured out how to fix it yet, but here is what I found in case anyone is interested.
So far it appears that BookWorm detects certain pattern in API calls of how NVDA retrieves more text. It appears that BookWorm returns empty paragraph at the end of the page and if that empty paragraph was requested a few times, then it assumes that it is time to turn page. Its page turning seems to be separate from NVDA page turning, e.g. I see some logic in sayall that triggers page turns in some other apps, but that logic is not triggered with BookWorm.
Now after my refactoring the sequence of API calls appears to be slightly different and this confuses BookWorm. I can actually see that in the refactored version NVDA finds this empty paragraph at the end of the page during sayAll, and also it requests next paragraph a few hundred times, still receiving empty paragraphs each time. Somehow page turning logic in BookWorm doesn't trigger in this case.
My preliminary conclusion is that this is peculiarity of BookWorm, as it expects some API calls in just the right sequence to trigger a page turn. I will try to identify which API call sequence did I change in my refactoring and I will try to mimick the old behavior.

[cary-rowen]

We might ask @mush42 to explain about Bookworm's page-turning mechanism.

[mush42]

Hi @cary-rowen @mltony

Here is how we do it:

• We use the default wx.TextCtrl which, in turn, uses the richedit control
• We add a custom WndProc for the richedit to be able to recieve WM_NOTIFY window messages
• We explicitly tell the underlying richedit to notify us about selection events, including empty selection, which identifies a caret move event, by adding the ENM_SELCHANGE flag to the control's event mask
• When our WndProc recieves a message whith a notification header code of EN_SELCHANGE we examine whether the selection type is SEL_EMPTY. If so, we add the message to a queue.
• A custom backround thread has an infinite loop that processes items from the queue, and fires a custom wx.Event if the latest caret position is different from the previous position
• If say all is enabled by the user, we process caret movement events, and if the caret is at the last (empty) line, and about 0.75 seconds has elapsed from the last page turn, we load the next page

Best
Musharraf

[seanbudd]

Blocking #13469, #13956

[lukaszgo1]

@seanbudd Please change the milestone for this issue - 2022.3 -> 2022.4