Display fringe only if not one-window-p?

Display fringe only if not one-window-p?

[Drew Adams]

I generally use one window per frame, and I automatically resize the frame
to fit the window (using
http://www.emacswiki.org/elisp/auto-resize-frames.el).

In Emacs 21 (.3.50), I would like to remove the fringe area for such
windows, but I don't necessarily want to remove the fringe area when a frame
has more than one window. Anyone know how to do this easily?

Better: Is there a way (an easy way) to associate a _predicate_ with display
of things like fringe area - to display the fringe area for a window, for
instance, only if a line wraps or is truncated?   I can of course modify
display-buffer, but I'm wondering if there is a clean and easier way.

Also, I don't see what fringes-outside-margins does. I've changed it to t or
nil and done set-window-buffer, but I don't seen any visible change.

Re: Display fringe only if not one-window-p?

[Kim F. Storm]

"Drew Adams" <drew.adams@oracle.com> writes:

> I generally use one window per frame, and I automatically resize the frame
> to fit the window (using
> http://www.emacswiki.org/elisp/auto-resize-frames.el).
>
> In Emacs 21 (.3.50), I would like to remove the fringe area for such
> windows, but I don't necessarily want to remove the fringe area when a frame
> has more than one window. Anyone know how to do this easily?
>
> Better: Is there a way (an easy way) to associate a _predicate_ with display
> of things like fringe area - to display the fringe area for a window, for
> instance, only if a line wraps or is truncated?   I can of course modify
> display-buffer, but I'm wondering if there is a clean and easier way.

It can probably be done with a post-command-hook:

call sit-for to update the display

then scan the fringes of each display line for
truncation bitmaps etc. with fringe-bitmaps-at-pos,

then use set-window-fringes to show/hide the fringes.

>
> Also, I don't see what fringes-outside-margins does. I've changed it to t or
> nil and done set-window-buffer, but I don't seen any visible change.

It is only used if the window has display margins (see set-window-margins).


-- 
Kim F. Storm  http://www.cua.dk

Re: Display fringe only if not one-window-p?

[Stefan Monnier]

> It can probably be done with a post-command-hook:
> call sit-for to update the display
> then scan the fringes of each display line for
> truncation bitmaps etc. with fringe-bitmaps-at-pos,

Hmm... that would work to detect when a fringe is present-but-empty.
How 'bout detecting when a fringe is absent-but-needed?


        Stefan

Re: Display fringe only if not one-window-p?

[Kim F. Storm]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

>> It can probably be done with a post-command-hook:
>> call sit-for to update the display
>> then scan the fringes of each display line for
>> truncation bitmaps etc. with fringe-bitmaps-at-pos,
>
> Hmm... that would work to detect when a fringe is present-but-empty.
> How 'bout detecting when a fringe is absent-but-needed?

You are right.

I thought (slippery memory) that the fringe bitmaps were still
determined internally even if the fringes have zero width, but they
are not.

However, it would be trivial to add a new variable force-fringe-bitmap-update
or some such which did the fringe calculations even for zero-width fringes.
WDYT?

-- 
Kim F. Storm <storm@cua.dk> http://www.cua.dk