Re: Emacs (nowindows) get confused about line display

["David M. Karr" <davidmichaelkarr@gmail.com>]

On 05/20/2016 05:45 PM, David M. Karr wrote:
> On 05/20/2016 04:28 PM, Emanuel Berg wrote:
>> "David M. Karr" <davidmichaelkarr@gmail.com>
>> writes:
>>
>>> On my CentOS laptop, I have a CentOS VM that
>>> I created with Vagrant. I have Emacs 24.3.1
>>> on the VM.
>>>
>>> I start a terminal window on the laptop and ssh
>>> to the VM. I run Emacs, but I don't have X11,
>>> so it's in "no windows" mode.
>>>
>>> Sometimes, when I start emacs on the VM, it
>>> starts up fine and displays properly.
>>>
>>> Quite often, and pretty continuously when it
>>> gets into this state, it will start up with
>>> a blank editor view, with no menu bar, and
>>> the cursor displays on the SECOND line of the
>>> window. When I then view or edit files, it
>>> appears that Emacs is confused about its line
>>> rendering. The cursor appears at the bottom
>>> of the window, even though it "thinks" it's
>>> on the top line of the file I'm viewing.
>>> I can scroll the cursor to the right, and it
>>> will jump back to the beginning when it
>>> reaches the length of the first line, and
>>> so on.
>>>
>>> Emacs is completely useless in this state.
>>>
>>> What can I do at this point?
>> You can analyze the whole chain of invocation.
>> What is the terminal emulator, shell, ssh
>> command, and Emacs invocation command? And if
>> you have tmux or something to that extent in
>> between any of those, that can influence, also.
>>
> Ok, well, $TERM appears to be "xterm-256color", shell is bash, I got 
> there with "vagrant ssh", and I execute Emacs with "emacs".
>
> That gave me the idea to run "emacs -q", and that does provide a 
> clue.  The display is fine after that, but when I load my .emacs after 
> the fact (eval-current-buffer), it's then messed up.  Before I do a 
> binary search to narrow down what initially creates the symptom, are 
> there any other guidelines for narrowing down something like this?
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.