Re: Start keybinding combination

[Ergus <spacibba@aol.com>]

On Sun, Jan 30, 2022 at 09:44:58PM +0200, Eli Zaretskii wrote:
>> Date: Sun, 30 Jan 2022 20:15:39 +0100
>> From: Ergus <spacibba@aol.com>
>>
>> If a user wants to start a command like `C-x r b` I would like to change
>> the mode-line color after the `C-x`. I suppose that this may be a call
>> to a hook in the same place that updates the echo area inserting the
>> current prefix.
>
>What would such a hook do to produce the effect that you want?  The
>mode-line color change will not be visible unless you force redisplay
>of the mode line.
>
Hi Eli:

My question comes from the fact that I see the prefix in the echo area
and it looks inconspicuous. So, some redisplay is actually done
right?. I thought that a hook and let the user implement something could
work.

Something like:

(add-hook the-new-hook (lambda ()
           (face-remap-add-relative 'mode-line :background some-color)))

And then call `face-remap-remove-relative` in the opposed|symmetric exit
hook... similar to what minibuffer-setup-hook/minibuffer-exit-hook do.

But I could be wrong.

Does it makes sense?