Re: Consistent face for keys in *Help* and `substitute-command-keys'

[Stefan Kangas <stefan@marxist.se>]

Juri Linkov <juri@linkov.net> writes:

> When the contrast with the default background is too low, then users
> will miss the highlighting, so when the user doesn't see that it has
> a different color then it will look as if there is no highlighting at all.

Yes, we definitely want to avoid that situation.

> But when it's slightly darker, then I see no problem for users.
> So it seems better to have a slightly darker color than to let users
> miss highlighting.
>
> To decide what would be a good default, you need to take into accounts
> opinions of the majority of users, but also possible problems
> that the default could cause to the minority of users.

Good, I think we agree on the principles.

The problem I have, and again that's just with my combination of eyes
and monitor, I find it hard to read when the background is too dark.

I suspect that my screen is simply darker than yours for some reason.
(Or my eyes are less sensitive to light, if that's a thing.)

> Maybe, I tried grey95, but when the prompt us at the bottom of the screen:
>
>   foo changed on disk; really edit the buffer? (y, n, r or C-h)
>
> highlighting of single letters is indistinguishable from the background.

This confirms that our situations are indeed different.

>> Here I see #fafbfc for keys, which is between gray98 and gray99, with an
>> added outline:
>>
>> https://docs.github.com/en/github/getting-started-with-github/keyboard-shortcuts
>
> Indeed, with a border, it's hard to miss highlighting.
[...]
> Then it's possible to use flat with rounded borders, without 3D effect.

What do you think of something like:

     :background "grey92" :foreground "DarkBlue"
     :box (:line-width 1 :color "grey80"))

On my screen, this is legible.  The DarkBlue and border makes it at the
same time stand out as highlighted.

I'm very open to another color (or indeed none at all, but it stands out
a bit more to me with something lighter than #000).  For me the DarkBlue
is very subtle, and my wife tells me the same (using her own set of
eyes, but my monitor).

If it doesn't work very well in your situation, could you propose
something which does?  Maybe we can tweak it so it is acceptable (or
even good) for us both, and then hope for the best.  With a bit of luck,
we are both close to the extreme ends of the spectrum here.  This
assumption could of course be wildly inaccurate, but then we can only
hope that someone protests.