bug#19395: 25.0.50; Setting left fringe to 0 messes up window-width

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sat, 20 Dec 2014 18:50:56 +0100
> From: martin rudalics <rudalics@gmx.at>
> CC: malsburg@posteo.de, 19395@debbugs.gnu.org
> 
>  >> You mean as far as the Emacs display engine is concerned, right?  But
>  >> the caller of `face-font' doesn't know that the display engine operates
>  >> on the current buffer regardless of whether it is displayed or not.
>  >
>  > She doesn't need to know: the effect doesn't depend on that.
> 
> If I want to right-adjust the last word of a buffer line I apparently
> have to provide the buffer _and_ the frame in order to know how many
> spaces to insert.

Yes, and with-current-buffer achieves that, right?

>  >> What means "applied"?  Is it merged or does it replace the
>  >> frame-specific face?
>  >
>  > It replaces the original frame-specific face.
> 
> IIUC this contradicts an earlier observation by Titus that
> 
>    if the buffer in the specified window is displayed in two frames,
>    the returned character width was always the one used in the current
>    frame which is not necessarily the character width in the specified
>    window (the window may be in the other frame).  This is a problem
>    because character width can be different, if the two frames use
>    different default fonts.

I don't see any contradictions.  I said nothing about windows, only
about frames and buffers.