bug#23755: 25.0.95; Emacs 25.0.95 Line number is in fringe

[Eli Zaretskii <eliz@gnu.org>]

> Date: Fri, 17 Jun 2016 18:41:34 +0100
> From: Alan Third <alan@idiocy.org>
> Cc: James Nguyen <ja.nguyen@gmail.com>, 23755@debbugs.gnu.org
> 
> >   emacs -Q
> >   (add-to-list 'load-path "/path/to/smart-mode-line-master")
> >   (load-library "smart-mode-line")
> >   (sml/setup)
> >   (dolist (sym '(mode-line mode-line-inactive))
> >         (set-face-attribute
> >          sym nil
> >          :box `(:line-width 2 :color ,(face-attribute `,sym :background))))
> > 
> > I see no display problems in the mode line after the above.
> 
> I just tried this on the NS port and it leaves stuff behind.

Then I guess it's either NS-specific or specific to the fonts you are
using.

> Aside from that, the digits seem to be placed wrongly. Sometimes
> they're fine, other times they're all wonky. I've attached a
> screenshot where it's displaying 404, but it looks like the 0 is too
> far left, and the second 4 is cut off, and another screenshot after I
> paged down and you can still see the left edge of the zero.

So what, the NS port cannot even display text correctly?

> I don't know how to tell what font it is, but I suspect it's
> variable-width and Emacs doesn't notice when they change size.

That cannot be true in general, since Emacs displays variable-pitch
fonts correctly since v21.1.

> For example, the misplaced 0 in 404 occurs after scrolling from a
> number starting with 3, and the 3 appears to be narrower than the
> 4. The second digit doesn't move right to compensate for the larger
> first digit.

That can only happen if the font lies to Emacs about the dimensions of
the character glyphs.

> Changing line-width to 1 in your code fixes it.

Which means the font does NOT lie, and thus the fact that some
characters are narrower than others is NOT the reason.