You can use the function set-hard-newline-properties to mark all newlines
in some range as hard. For the inverse you can remove the 'hard property
with (remove-text-property START END '(hard nil)).

On Thu, Dec 14, 2017 at 2:44 PM, Uwe Brauer <oub@mat.ucm.es> wrote:


> Hi
>
> For email I start to use messages-are-flowing.el (for example in this
> message) which insert and display hardlines. (This is useful when sending
> message to devices with small screens since then the line ending is better
> displayed).
>
> However sometimes it is a bit too much. So I still have a function which
> replaces softline by hardlines, namely
>
> (defun harden-newlines () (interactive)  (save-excursion ;    (goto-char
> (point-min))    (mail-text) (while (search-forward "\n" nil t)
> (put-text-property (1- (point)) (point) 'hard t))))
> So I thought the inverse operation could be
> (defun soften-newlines () (interactive)  (save-excursion ;    (goto-char
> (point-min))    (mail-text) (while (search-forward "\n" nil t)
> (put-text-property (1- (point)) (point) 'soft t))))
> But unfortunately this did not work out. I tried to google for the
> put-text-property function but did not find anything useful.
>
> Somebody has an idea how to do that, replace hardlines again by softlines?
>
> Thanks
>
> Uwe Brauer
>
> ​