Re: Regarding on-key-up event

[Po Lu]

Also, I forgot to say that key press repetition is implemented in the X server, 
not a toolkit.

On February 4, 2023 7:45:20 AM GMT+08:00, Ag Ibragimov 
<agzam.ibragimov@gmail.com> wrote:
>Eli Zaretskii <eliz@gnu.org> writes:
>
>Sorry Eli, I accidentally replied without CC, so this one would show up
>for you twice. My apologies.
>
>>> From: Ag Ibragimov <agzam.ibragimov@gmail.com>
>>> Cc: emacs-devel@gnu.org
>>> Date: Fri, 03 Feb 2023 13:25:53 -0600
>>> 
>>> > I don't think I understand the question.  Emacs produces a key event
>>> > when a key was pressed and then released.  So technically, we already
>>> > have an "on-key-up" event.
>>> 
>>> But you can't register "on-release" event, right? That makes for example
>>> difficult to implement UX similar to an app switcher in a desktop
>>> manager - Alt+Tab. Where as long you keep holding Alt, pressing Tab
>>> performs an action, but releasing Alt-key gets you out.
>>
>> Yes, you can "register" an on-release event, just not for modifier
>> keys like Shift or Alt.
>>
>
>Wait, really? Are you saying that aside the modifier keys, it's possible to 
>let's say
>bind a command to a key e.g., (kbd "a"), so when a user presses the key,
>it would to run one command, but when the key is released to run a
>different command?
>
>>> Or even something much simpler, like temporarily increasing the
>>> font-size while you hold the key.
>>
>> While you hold a key, a typical keyboard auto-repeats, so I see no
>> problem here.
>
>Right, it would auto-repeat, registering a sequence of "key-pressed"
>events, but can we detect when the key gets released?
>