Single modeline for all buffers?

Single modeline for all buffers?

[Göktuğ Kayaalp]

Hi, is it possible to have Emacs show only one modeline at the very
bottom of the screen, which shows information about the buffer in the
selected window? E.g. instead of this,

     | [#]include <stdio.h>     | (defun add (x y) (+ x y)\|
     | int main(int argc, char \| )                        |
     | ** argv, char ** envp) { | (ad[d] 5 6) ;=> 11       |
     -------------------------------------------------------
     |-:-- hello.c  Top (1, 0)  |-:**- *scratch* Top (2, 2)|
     -------------------------------------------------------
     |                                                     |
     -------------------------------------------------------

Can I have sth. like the following?

     | [#]include <stdio.h>     | (defun add (x y) (+ x y)\|
     | int main(int argc, char \| )                        |
     | ** argv, char ** envp) { | (add 5 6) ;=> 11         |
     -------------------------------------------------------
     |-:-- hello.c  Top (1, 0)   (C/l Arev AC hl-p hl-s Abb|
     -------------------------------------------------------
     |                                                     |
     -------------------------------------------------------

Cheers

--
GK

«Most people do not listen with the intent to understand; they listen
 with the intent to reply.»
                                                      — Stephen R. Covey

Re: Single modeline for all buffers?

[Søren Pilgård]

On Wed, Feb 5, 2014 at 10:38 AM, Göktuğ Kayaalp <self@gkayaalp.com> wrote:
>
> Hi, is it possible to have Emacs show only one modeline at the very
> bottom of the screen, which shows information about the buffer in the
> selected window? E.g. instead of this,
>
>      | [#]include <stdio.h>     | (defun add (x y) (+ x y)\|
>      | int main(int argc, char \| )                        |
>      | ** argv, char ** envp) { | (ad[d] 5 6) ;=> 11       |
>      -------------------------------------------------------
>      |-:-- hello.c  Top (1, 0)  |-:**- *scratch* Top (2, 2)|
>      -------------------------------------------------------
>      |                                                     |
>      -------------------------------------------------------
>
> Can I have sth. like the following?
>
>      | [#]include <stdio.h>     | (defun add (x y) (+ x y)\|
>      | int main(int argc, char \| )                        |
>      | ** argv, char ** envp) { | (add 5 6) ;=> 11         |
>      -------------------------------------------------------
>      |-:-- hello.c  Top (1, 0)   (C/l Arev AC hl-p hl-s Abb|
>      -------------------------------------------------------
>      |                                                     |
>      -------------------------------------------------------
>
> Cheers
>

One problem with this is distinguishing the border between two buffers
above/below each other.  You might still want some kind of bar rendered there,
perhaps with a different content?

Re: Single modeline for all buffers?

[martin rudalics]

 > Can I have sth. like the following?
 >
 >      | [#]include <stdio.h>     | (defun add (x y) (+ x y)\|
 >      | int main(int argc, char \| )                        |
 >      | ** argv, char ** envp) { | (add 5 6) ;=> 11         |
 >      -------------------------------------------------------
 >      |-:-- hello.c  Top (1, 0)   (C/l Arev AC hl-p hl-s Abb|
 >      -------------------------------------------------------
 >      |                                                     |
 >      -------------------------------------------------------

Not really.  This would require a major redesign of the involved
components.  If you have Emacs 24.4 you can try (better with Emacs -Q)
the proof of concept below (for fun only).

If you are really interested, you'd have to fill in two things:

(1) A mechanism that would allow this to work with multiple frames (that
     is, things like mode-line-buffer and mode-line-window would have to
     become frame parameters).  This is fairly easy.

(2) A mechanism to implement keybindings in the mode-line buffer.  This
     should be easy too but is likely tedious.  You would mostly have to
     replace occurrences of

       (with-selected-window (posn-window (event-start event))

     with something like

       (with-selected-window mode-line-really-selected-window

     where mode-line-really-selected-window would refer to the window the
     mode-line is currently talking about.

martin


(defvar mode-line-buffer (get-buffer-create "mode-line"))

(defvar mode-line-window (display-buffer-in-side-window mode-line-buffer nil))

(defvar original-mode-line nil)
(make-variable-buffer-local 'original-mode-line)

(with-current-buffer mode-line-buffer
   (font-lock-mode -1)
   (setq mode-line-format nil))

(defun mode-line-buffer-list ()
   (walk-window-tree
    (lambda (window)
      (with-current-buffer (window-buffer window)
        (when mode-line-format
	 (setq original-mode-line-format mode-line-format)
	 (setq mode-line-format nil))))))

(defun mode-line-post-command ()
   (let ((format original-mode-line-format)
	(buffer (current-buffer))
	(window (selected-window)))
     (with-selected-window mode-line-window
       (erase-buffer)
       (insert (format-mode-line format 'mode-line window buffer))
       (let ((window-min-height 1)
	    (window-resize-pixelwise t))
	(setq window-size-fixed nil)
	(fit-window-to-buffer)
	(set-window-start nil (point-min))
	(setq window-size-fixed t)))))

(with-selected-window mode-line-window
   (buffer-face-set 'mode-line)
   (setq default-frame-alist '((right-divider-width . 4) (bottom-divider-width . 4)))
   (set-window-margins nil 0 0)
   (set-window-fringes nil 0 0)
   (set-window-scroll-bars nil 0)
   (setq cursor-type nil)
   (set-window-parameter nil 'no-other-window t)
   (set-window-dedicated-p nil t))

(add-hook 'post-command-hook 'mode-line-post-command)
(add-hook 'buffer-list-update-hook 'mode-line-buffer-list)

RE: Single modeline for all buffers?

[Drew Adams]

My response would be: why?
A mode line is mode-specific by design.

Sounds like this might be an XY problem.
http://meta.stackoverflow.com/questions/66377/what-is-the-xy-problem

What is the real problem you are trying to solve or the
real feature you are looking for?  Can you describe it without
mentioning the mode line?