bug#20847: [display engine] 25.0.50; company-mode popup makes point jump to an entirely different location

[Eli Zaretskii]

> Cc: 20847@debbugs.gnu.org
> From: Dmitry Gutov <dgutov@yandex.ru>
> Date: Sun, 21 Jun 2015 23:01:10 +0300
> 
> On 06/21/2015 09:09 PM, Eli Zaretskii wrote:
> 
> > There are only 2 situations, from your POV: either a line goes all the
> > way to the window edge, or it doesn't.
> 
> Could you suggest the best way to check whether the former is the case?
> 
> (>= (car (posn-col-row (posn-at-point)))
>      (window-width))

Something like that, but perhaps using end-of-visual-line as well.

>  >   The former can happen either if there's a newline that ends a line, 
>  > or if word-wrap is in effect.
> 
> Does that constitute at least three different cases we'd need to handle?
> 
> - Not near the window edge
> - near the edge and newline
> - near the edge and no newline?

I'm not sure I understand the meaning of "near" here.  Can you define
what "near the edge" means, in this context?  Does it mean "close", as
in "less than N columns away", or does it mean "flushed all the way to
the edge", i.e. not even a single column between the last character
and the window edge?

> > Yes, there could be such artifacts, but IMO losing some of the text is
> > worse.
> 
> I'm not sure what you mean by "losing some of the text".

The rightmost characters in each continued line are removed from
display because you put a newline there.