bug#53776: Modeline indicator when using define-minor-mode

[Stephen Berman]

On Mon, 07 Feb 2022 01:51:25 +0100 Michael Heerdegen <michael_heerdegen@web.de> 
wrote:

> Stephen Berman <stephen.berman@gmx.net> writes:
>
>> Since I don't have mouse-4 and mouse-5
>
> These are the "keys" associated with the mouse wheel.  In case you want
> to scroll with the mouse wheel.

Ah, ok.

>> I just tried evaluating that sexp with integral values (1, 0, -1) for
>>ml-scroll-amnt, and only got truncation.  Maybe I don't understand what
>>you mean by "let mouse-4 and mouse-5 over the mode-line de- and
>>increase `ml-scroll-amnt'".  Can you show me bindings I can try with a
>>3-button mouse, or just with the keyboard?
>
> I dunno how you want to scroll.  Drag with mouse-1, scroll with a wheel
> or a key, something else?
>
> The code
>
> #+begin_src emacs-lisp
> (defvar ml-scroll-amnt 0)
>
> (setq-default
>  mode-line-format
>  `(:eval (substring (format-mode-line ',mode-line-format)
>                     ml-scroll-amnt)))
> #+end_src
>
> has to be evaluated once.  Mode-line looks like before.
>
> (setq ml-scroll-amnt 3) scrolls the mode-line three chars to the left.
> (setq ml-scroll-amnt 0) to scroll back.  Changing `ml-scroll-amnt'
> changes the scroll amount.
>
> How you implement changing the binding of `ml-scroll-amnt' is up to you,
> depends on how you want it to be.

Ok.  When I have more time to spend on this, I'll try to do it.

Steve Berman