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Re: New key binding syntax


From: Yuri Khan
Subject: Re: New key binding syntax
Date: Fri, 5 Nov 2021 17:03:19 +0700

On Fri, 5 Nov 2021 at 16:13, Alexandre Garreau <galex-713@galex-713.eu> wrote:

> so it’s like a down, b down, …, f down… and then until I release any key
> between a and f, if I press down “g”, the keyboard won’t say anything to
> the application/OS?

As I said, it depends. (Also, I’d like to see you do that with just
your left hand.)

    q w E r t
     A s D F G
      z x C v B

> wdym by “simultaneously”? “close enough in time of pressing”? or “while
> the others haven’t been released yet”?

The latter.

> what? I thought the usb kbd firmware worked by sending events that
> triggered interruptions, not that it stored keystate itself :o I thought
> keystate was saved and registered application-side, with each event

Well, this explains your reactions. What travels over the wire is the
state (level), not the changes (edges). It is the OS, input subsystem
of the desktop, and possibly toolkit, that translates that into press,
release, and autorepeat events.

Otherwise, for example, what would happen if you held down a bunch of
keys and then unplugged the keyboard? Should the host system remember
that these keydowns originally came from device X and auto-generate
posthumous keyups for them when device X is unplugged?

(It is also the OS and the desktop’s input subsystem that interprets
keyboard layouts and turns a Shift+AB01 into a capital Z on a US
system or capital Y on a German system. But you probably knew that.)



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