Re: [AUCTeX] Spurious newline after folded macros.

[Ikumi Keita]

Hi Joost,

>>>>> Joost Kremers <address@hidden> writes:
> Hi all,
> On Fri, Mar 23 2018, Joost Kremers wrote:
>> After the recent AUCTeX update to version 12.1.1 (which I installed
>> just two days ago, due to having been on vacation), I noticed a
>> strange problem with TeX-fold-mode. After a folded macro, there is a
>> spurious newline, i.e., the text is continued on the next line, even
>> though there is no newline in the actual text.

> I posted this message about a month ago, but I haven't received any
> replies. I *really* don't want to be the guy that starts whining when
> their question goes unanswered on a public mailing list, but this
> issue happens even with `emacs -Q', so I find it hard to imagine that
> I'm the only one seeing it...

> I just realised that I can examine the contents of the overlay with
> `C-u C-x =', and so I did, and I found that indeed, the overlay
> contains an extra "\n". This is for example the overlay on
> "\textit{Aliquam}" in the screenshots I sent:

> #("Aliquam\n" 0 7
>  (wrap-prefix "" face
>               (font-latex-italic-face)
>               fontified t))

> I also noticed that sometimes, the newline isn't added, though I
> haven't been able to figure out what conditions it. I have, for
> example, an \item in a beamer presentation that shows the problem, but
> when I make the text of the \item shorter, the problem disappears. (I
> confirmed that in the former case, the overlay text is "*\n" and in
> the latter just "*".)

> So here's hoping this time around someone may be able to help. 

Thank you for your report.  I think I found out the origin of the
behavior you reported.  Could you please try the following modified
function?  I.e., put the point (cursor) just after the last ")", type
C-x C-e and try folding again in the latex document buffer.  I expect
that the previous behavior is recovered.
If this fixes the problem, I'll install the change in the git
repository.

(defun TeX-fold-overfull-p (ov-start ov-end display-string)
  "Return t if an overfull line will result after adding an overlay.
The overlay extends from OV-START to OV-END and will display the
string DISPLAY-STRING."
  (and
   (save-excursion
     (goto-char ov-end)
     (search-backward "\n" ov-start t))
   (not (string-match "\n" display-string))
   (> (+ (- ov-start
            (save-excursion
              (goto-char ov-start)
              (line-beginning-position)))
         (length display-string)
         (- (save-excursion
              (goto-char ov-end)
              (line-end-position))
            ov-end))
      (current-fill-column))))

Regards,
Ikumi Keita