bug-gnu-emacs
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

bug#18417: 24.3.93; posn-at-point confused by fill-column-indicator


From: Alp Aker
Subject: bug#18417: 24.3.93; posn-at-point confused by fill-column-indicator
Date: Sun, 7 Sep 2014 23:11:35 -0400

> The recipe in effect invokes undefined behavior in posn-at-point,
> because fci-mode uses a zero-length (a.k.a. "empty") overlay to
> place, in a very convoluted way, a stretch of whitespace followed
> by an image, before the newline.
[snip]
> Since the buffer position of the newline is not "covered" by the
> empty overlay, Emacs happily stops when it reaches the newline,
> oblivious to the fact that on the way it produced the stretch
> glyph of a very large width.

I'm not sure it's due to the overlay having zero length.  Here's a minimal recipe that provokes the same behavior using a overlay of length 1 (covering the newline):

(progn
  (delete-all-overlays)
  (goto-char (point-min))
  (insert "\n")
  (setq o (make-overlay 1 2)
        s (propertize " "
                      'display '(space :align-to 10)
                      'cursor t))
  (overlay-put o 'before-string s)
  (goto-char (point-min))
  (setq col (car (posn-col-row (posn-at-point (point)))))
  (message (concat "Current column: " (number-to-string col))))



reply via email to

[Prev in Thread] Current Thread [Next in Thread]