bug#1305: All code that currently beeps should use visual bell instead

[Dmitry Gutov]

On 19.04.2021 16:16, Gregory Heytings wrote:
> > 'match' for purposes other than matching?
>
> Why not?  That would be only a default value, to call the user's 
> attention that the reason of the error is displayed there.  IMO using 
> yellow for that purpose is much better than green (highlight face).

Perhaps I'm just used to the 'inverse-video' effect on GNU/Linux, but 
that monochrome effect (having black and white switch places on two 
lines of the frame) is both noticeable but not alarming.

> > And speaking of 'error', seeing red is most likely more obtrusive than 
> > the current GNU/Linux behavior.
>
> Do you really mean that seeing the cursor becoming red during 0.25 
> seconds is obtrusive?

The cursor itself will be a mild disturbance, the colorful flash at the 
bottom should be a tad more jarring.

I'm not sure if red is a good choice, though. After all, the action we 
just performed (abort/quit) does not necessarily imply any kind of error.

> The current GNU/Linux default behavior is (for those who use Gnome or 
> KDE and have not disabled the system bell) to ring the system bell 
> (typically during 0.5 seconds).  That's IMO far more obtrusive (in 
> particular for your colleagues!) than seeing the cursor becoming red and 
> the echo area flashing during a fourth of a second.

I'm comparing to the (setq visible-bell t) behavior on GNU/Linux.