Re: Emacs (nowindows) get confused about line display

[Eli Zaretskii <eliz@gnu.org>]

> From: John Mastro <john.b.mastro@gmail.com>
> Date: Fri, 20 May 2016 18:19:00 -0700
> Cc: "help-gnu-emacs@gnu.org" <help-gnu-emacs@gnu.org>
> 
> David M. Karr <davidmichaelkarr@gmail.com> wrote:
> > Actually, narrowing it down didn't take very long, but I'd still like to
> > understand this better.
> >
> > The 2-3rd line of my .emacs file has this:
> > --------------------------
> > (set-frame-position (selected-frame) 0 0)
> > (set-frame-height (selected-frame) 60)
> > ----------------
> >
> > This is obviously not relevant in a emacs-nw situation, but I copied this
> > from my "home" .emacs file.  Why would this cause the symptom that I'm
> > seeing?
> >
> > It's easy enough to wrap this with a "(display-graphic-p)" call, but I'd
> > like to understand why this is happening.
> 
> It looks like the problem is with the call to `set-frame-height'
> specifically. `set-frame-position' has no effect on a tty frame.
> 
> Further, (set-frame-height (selected-frame) (frame-height)) didn't cause
> any problems in my experiments; only when I set a wrong frame height did
> I get Emacs into a bad state. So it's not that `set-frame-height'
> inherently breaks things on a tty.
> 
> However, I don't know whether there are scenarios where it makes sense
> to call `set-frame-height' on a tty frame, or if this is just one of
> those "well don't do that" situations.

I suggest to upgrade to a later version of Emacs, but in general, my
advice is not to use set-frame-height in TTY sessions.  That function
does produce a non-trivial effect on a TTY, but the effect is only
useful for debugging Emacs, not for normal usage.