Note on using keyboard as input machine

[user202729]

I recently switch to installing Qwerty-like mode on Georgi. Some notes.

• I modified the source code to implement first-up chord send and filter to take only input from Georgi.
Should write proper input plugin some day.
• On X, Plover calls set keyboard map when the Unicode character is not on the map; however when there are 2 physical keyboards it seems that xmodmap is independent, so it's possible that Plover sets xmodmap for one keyboard (the physical keyboard) then do the output with the other keyboard (xtest).

Maybe something to do with XKB not beingsupported (*), so supporting it would be the best option; however the documentation of python-xlib is less than ideal (should I look at the C API documentation and figure out?)
See discussion in #1164 (and some linked issues).

Reattaching like mentioned in #1030 apparently (seems to) fix the Unicode output error, but it's not permanent. I should also figure out how to listen for new keyboard connect/etc. and patch accordingly (*).

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Anyway, looking around a bit ("where is the documentation?") I figured out roughly how Python-xlib + C libx11 + xserver + the communication protocol works

• someone already implemented the change hierarchy wrapper https://github.com/python-xlib/python-xlib/pull/57
• link to a PR with ext.shape being automatically generated, and Benoit's generating script

Either way, sticking to subprocess.run() should be good for now.

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Documentation links and miscellaneous

• https://unix.stackexchange.com/questions/146287/monitoring-events-keyboard-mouse-in-x → need to listen for HierarchyChanged events (can)
• don't need to grab
• there's the PR linked above for calling ChangeHierarchy from Python, but because Python-xlib is a bit "unmaintained" by now I guess I'll stick with subprocess.run().
• https://tronche.com/gui/x/xlib/
• https://github.com/python-xlib/python-xlib
• https://www.x.org/docs/XProtocol/proto.pdf
• https://github.com/freedesktop/xorg-xinput , https://github.com/freedesktop/xorg-xserver: source code of tools

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For now, I implement a source code patch in user202729@8ab18b4 .