il-keebd VS composite-joystick

Going to toot my own horn a little bit here. I used this capability on this work project: https://github.com/nhsx/il-magic-scanner (long story short: use a pi camera to read ID info off a phone screen, then pretend to be a keyboard and "type" it into an attached computer). There's a spun-off standalone daemon at https://github.com/nhsx/il-keebd which handles the "pretend to be a keyboard" bit. It listens on a local socket for text, converts it to scancodes, and squirts them up to the usb host.

The keymap isn't complete by any means, but it's got enough there to be interesting.

I've done this, it's super useful. The use case for me was that I wanted to simultaneously use two joysticks with the same game, mixing their inputs together instead of just using one or the other for each axis. The behavior only ended up being possible by writing a "joystick mux" program that would accept input from multiple joysticks and then retransmit it as a gadget-mode device.

Side note, USB HID descriptors are a disaster and someone should do something about it. Even commercial devices by reputable manufacturers have broken descriptors. A tool with modern ergo and integration would probably get a surprising amount of traction.

https://github.com/saulrh/composite-joystick