Re: fill length of visual line mode

[Stefan Monnier <monnier@iro.umontreal.ca>]

> It just boils down to setting the right margin. I have to hide the right
> fringe or it looks wrong.

Better to swap the margin and the fringe with fringes-outside-margins.

> (defun ivan-gnus-hack-visual-line-length ()
>   "Set visual line length by expanding the right margin of the
> buffer’s window."
>   (let ((window (selected-window)))
>     (select-window (car (get-buffer-window-list gnus-article-buffer)))
>     (set-window-margins nil 0 (- (window-width) 80))
>     (set-window-fringes (selected-window) 8 0)
>     (visual-line-mode)
>     (select-window window)))

You want to use `with-selection-window' above.
Additionally, the above will lose its effect if you hide the window and
show it again: you'd need to do it via window-configuration-change-hook.
Other problem: if window-width is smaller than 80 (which I gather is
your target fill-column in the above code), you end up setting
a negative margin.

> It just feels hackish and wrong.  The right thing I feel is to use
> fill-column.

I'm not opposed to a patch that would let it obey fill-column
(optionally).  But it does beg the question: what if the window is
smaller than fill-column?  Should it then fill at the window's edge or
should it continue as if truncate-lines is set?


        Stefan