Re: Bigger fringe bitmaps

[Yuri D'Elia <wavexx@thregr.org>]

On Thu, Mar 17 2022, Eli Zaretskii wrote:
> I did comment on that.  To repeat: it could be a useful new feature,
> but I don't think it should be _the_ solution for showing stuff on the
> fringes on hidpi terminals; we should be able to produce legible
> display of the bitmaps on those terminals.

Seen it, I was just prompting for more feedback on the idea and discuss
if this could be a good and/or bad idea.

>> I like the idea of using 🢱 (or ⤶⤷) for wrapped text, 🮗 as a
>> end-of-buffer, and so on. Easily scaled, and nicely antialiased.
>
> You disregard the issue of which fonts support what characters in the
> relevant Unicode blocks.

Definitely.

> Solving this in the limited fringe screen estate will need some
> non-trivial ideas. And what about 'half-width' or 'minimal'
> fringe-styles?

I mentally imagine this as just scaling the font smaller to fit the
fringe width, centering each character vertically.

>> Especially the fact that this would potentially mean an usable fringe
>> mode on character displays that can be toggled, so that you don't need
>> to provide an alternate signaling mechanism if you rely on the fringe to
>> show makers (like gud).
>
> I don't think I follow.  Emacs doesn't support fringes on TTY
> displays, so what do you mean by "usable fringe mode on character
> displays"?

That would be part of the advantage of allowing a character to be used
in lieu of a bitmap (either as a feature or as a fallback).

On a TTY we could just reserve the first/last column for the "fringe"
and display the lowest-common-denominator format available.

> This is already supported, see overlay-arrow-string. Or do you mean
> something else?

Yes, but it doesn't behave exactly in the same way as the fringe does.

(and I also as I just discovered, if I disable the fringe on a graphical
display I do not get the overlay arrows as a fallback -- or did I miss
some variable to control this behavior?)