bug#37689: Fringe pixmaps, widgets, etc. look ridiculously tiny in hidpi screen

[Carlos Pita]

On Thu, Oct 10, 2019 at 12:05 PM Eli Zaretskii <eliz@gnu.org> wrote:
>
> > From: Robert Pluim <rpluim@gmail.com>
> > Cc: Eli Zaretskii <eliz@gnu.org>,  37689@debbugs.gnu.org
> > Date: Thu, 10 Oct 2019 16:21:16 +0200
> >
> > Perhaps we should convert those pixmaps to some scaleable format, and
> > then autoscale them?
>
> You mean, SVG?  We could do that, but we'd like images to display well
> even if Emacs cannot display SVG.
>
> Also, I think fringe bitmaps and other icons we use in the UI cannot
> be scalable, we need to scale them ourselves.  Not that I'm an expert
> on that (so don't take my words as definitive and/or final).

At least for the fringe part, what do you think of modifying
define-fringe-bitmap to take into account scaling factor?

For example, if scaling factor > 1.5 make everything x2, if > 2.5 then
x3, etc. It seems quite simple to achieve those integer scalings.