Allow enabling Plover on a subset of keyboards

[user202729]

(as explained in the title.)

Sometimes the user might want to use a mechanical keyboard to type in steno and the normal keyboard to type in Qwerty. It should not be necessary to PHROLG every time.

Extension: allowing multiple keyboards to be able to type in different steno systems.

Another extension: recognizing input from multiple types of machines at once.
(perhaps this is not very useful, same way as how people only type from one keyboard at a time; besides, perhaps keyboard+professional steno machine is the most common option)

[benoit-pierre]

Possible on Linux (the code pretty much already support it: you can try changing XINPUT_DEVICE_ID in plover/oslayer/xkeyboardcontrol.py). From what I remember, hard to impossible on Windows (standard API don't allow differentiating devices). No idea about macOS.

[user202729]

It might be possible on Windows:

https://www.codeproject.com/articles/716591/combining-raw-input-and-keyboard-hook-to-selective

Perhaps ctypes can also be used here, like how it was used for the hook API.

Root (administrator) privilege appears to be unnecessary, unless the driver method is used.

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Related: https://github.com/boppreh/keyboard/issues/21#issuecomment-320483942 (avoid GitHub issue linking) -- for unknown reasons, that comment claims that the hook event comes after the device id so blocking is harder; while the article above claims that the hook is before -- see also the last comment.

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This feature can be implemented in a separate (machine) plugin as well, although there might be significant code duplication with Plover's keyboard/oslayer module.

[user202729]

Testing around a bit macOS can
CGEventGetIntegerValueField(event, kCGKeyboardEventKeyboardType) to distinguish different keyboards... on another read, it merely distinguish between different keyboard layouts (40: ANSI, 88: macOS layout, etc.?)

https://github.com/Hammerspoon/hammerspoon/issues/2643 (no crosslink) contains some more information.

It links to a C program that shows how to suppress all keys in internal keyboard, but that requires IOKit.

Unfortunately, IOKit will not be wrapped in pyobjc... although it looks like there are different libraries.

[user202729]

With all the pending reorganization on oslayer, it would be somewhat hard to get this implemented...

[user202729]

Thinking about it, if this is enabled it would also make sense to set the keyboard error to "disconnected" when none of the keyboards in the subset can be found.

It would be better to disable plover-auto-reconnect-machine plugin with this feature though (because the plugin is hardcoded to check serial port only)

I implemented the feature in my test dev branch, seems to work well. Only for X though since that's the one I need the most.

(also because my keyboard connection is a bit fickle, so seeing whether it's connected is very useful)

[user202729]

My original plan is to develop something like this:

But I realize it is overkill, because it is highly unlikely that the user would want to use more than one keyboard anyway.

There's just one case where it makes sense to enable on all keyboards: when the user uses the default configuration (and there are multiple keyboards connected). Then, we wouldn't know which keyboard the user want to use.

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In retrospect, it would also makes sense to allow setting arpeggiate per keyboard. But implementing all the logic correctly is going to be difficult.
(essentially we want to run multiple machines in parallel, each one collecting key presses and send strokes independently. But if someone needs that feature, it would be beneficial to listen for multiple machines at the same time as well...)

[aerickt]

I'm actually running into this issue. I use a Multisteno with Plover as my main keyboard, but I'm also currently trying to learn controller steno. Having to switch the protocol between Gemini PR and Controller is really cumbersome and annoying.

[user202729]

This is not exactly what this issue addresses (although it is addressed in the extension "Allow from multiple inputs"). If the protocol is different, you can simply use a translation with the format

{plover:set_config:'machine_type':'Gemini PR'}

to switch between them.

Of course, there's also a small problem is if you want to switch from Controller to Gemini PR then you need to press the chord on the controller.