dot-files/.emacs.d/config/window-management.el

;; (C) Copyright Collin J. Doering 2014
;;
;; This program is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
;; 
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.
;; 
;; You should have received a copy of the GNU General Public License
;; along with this program.  If not, see <http://www.gnu.org/licenses/>.

;; File: window-management.el
;; Author: Collin J. Doering <collin.doering@rekahsoft.ca>
;; Date: Oct 22, 2014

;; Use this function to create a X11 emacs frame with a static name so it can
;; be treated specially by xmonad (as a scratch-pad in this case). This is expected
;; to be run from command-line like so:
;;    emacsclient --eval '(make-frame-with-static-name "emacs-scratch")'
(defun make-frame-with-static-name (given-name)
  "Makes a (X11) frame with a unchanging name for the purposes of finding it with
a window manager, and treating it specially."
  (select-frame (make-frame `((name . ,given-name)))))

;; Toggles windows split orientation of 2 adjecent windows
;; Thanks to http://www.emacswiki.org/cgi-bin/wiki?ToggleWindowSplit
(defun toggle-window-split ()
  (interactive)
  (if (= (count-windows) 2)
      (let* ((this-win-buffer (window-buffer))
	     (next-win-buffer (window-buffer (next-window)))
	     (this-win-edges (window-edges (selected-window)))
	     (next-win-edges (window-edges (next-window)))
	     (this-win-2nd (not (and (<= (car this-win-edges)
					 (car next-win-edges))
				     (<= (cadr this-win-edges)
					 (cadr next-win-edges)))))
	     (splitter
	      (if (= (car this-win-edges)
		     (car (window-edges (next-window))))
		  'split-window-horizontally
		'split-window-vertically)))
	(delete-other-windows)
	(let ((first-win (selected-window)))
	  (funcall splitter)
	  (if this-win-2nd (other-window 1))
	  (set-window-buffer (selected-window) this-win-buffer)
	  (set-window-buffer (next-window) next-win-buffer)
	  (select-window first-win)
	  (if this-win-2nd (other-window 1))))))

;; TODO: Modify the below function to accept the universal argument.
;;       Specifically an integer argument (n) where:
;;         - if negative denotes backwards rotation repeated |n| times
;;         - if positive denotes forwards rotation repeated n times
;;         - otherwise, no numerical value is given for the universal argument; ignore. 

;; Rotates windows
;; Thanks to http://www.emacswiki.org/emacs/TransposeWindows
(defun rotate-windows ()
  "Rotate your windows"
  (interactive)
  (cond
   ((not (> (count-windows) 1))
    (message "You can't rotate a single window!"))
   (t
    (let ((i 0)
          (num-windows (count-windows)))
      (while  (< i (- num-windows 1))
        (let* ((w1 (elt (window-list) i))
               (w2 (elt (window-list) (% (+ i 1) num-windows)))
               (b1 (window-buffer w1))
               (b2 (window-buffer w2))
               (s1 (window-start w1))
               (s2 (window-start w2)))
          (set-window-buffer w1 b2)
          (set-window-buffer w2 b1)
          (set-window-start w1 s2)
          (set-window-start w2 s1)
          (setq i (1+ i))))))))

;; Assign keybinding to toggle split orientation of 2 adjacent windows, and to rotate windows
(define-key ctl-x-4-map "t" 'toggle-window-split)
(global-set-key "\C-cr" 'rotate-windows)