Re: Layered display API

[Eli Zaretskii]

> Date: Thu, 14 Aug 2014 06:35:11 +0400
> From: Dmitry Gutov <address@hidden>
> CC: address@hidden, address@hidden
> 
> I've been under impression that "tty menus" could work in graphical 
> mode, too, but now I understand that they're non-portable, like the name 
> suggests. That's too bad.

Doing the same on GUI frames would hit all the difficulties that we've
been discussing in this thread, due to proportional and variable-size
fonts, and other display features that don't exist on a TTY.  More
importantly, the TTY menus were developed because there were no menus
on text-mode frames, a problem that didn't exist on GUI frames.

> Why use the special new property, then? Just put a new overlay over it. 
> If it also has `display' and higher priority, it would take over.

Because you want to get priority not only over other overlays, but
also over display properties and maybe other things.

> >> Will the menu allow me to customize the keymap it's using?
> >
> > Of course!  This is Emacs.  See the end of menu-bar.el: the menu
> > navigation keys are defined as a keymap.
> 
> So, you would suggest I dynamically rebind `tty-menu-navigation-map'?

If you need that, yes.