bug#31020: 27.0; Please provide a way to know about menu-bar wrapping

[Drew Adams <drew.adams@oracle.com>]

> So what you can do is the following: Make a frame with a _visibly
> unwrapped_ menu bar, get the menu bar height via
> (cddr (assq 'menu-bar-size (frame-geometry)))
> 
> Do the same for a frame with a _visibly wrapped_ two-lines menu bar.
> You can now derive the height of the single-line and any additional
> menu bar line and use these values together with 'frame-geometry' for
> getting the actual number of lines.

That's good to know; thanks.  But I don't think it will
help code that has only a given frame to examine, e.g.,
code that doesn't want to bother some user by creating
or resizing frames to determine this.  And anyway, the
_code_ cannot, by itself, tell the _visibly wrapped_
condition.

IOW, that suggestion might help a user to determine,
by looking, what the situation is.  But I don't see how
I could use in from Lisp to know what the situation is.
Let me know, if I'm missing something simple.

> Obviously, this will work only as long as you do not change themes,
> the menu bar height of the current theme or the resolution of your
> screen or whatever else could affect this.  And since you have to
> visuallly check the "wrappedness" of the menu bar, this work cannot be
> reasonably done from within Emacs.

Ah, that's just what I meant above.  Thanks for confirming.