Here are two functions that do the same. Note that these will only work for two windows.
;; Swap windows
(defun swap-windows ()
(interactive)
(if (= (count-windows) 2)
(let* ((this-win-buffer (window-buffer))
(next-win-buffer (window-buffer (next-window))))
(set-window-buffer (next-window) this-win-buffer)
(set-window-buffer (selected-window) next-win-buffer))))
(define-key ctl-x-4-map "s" 'swap-windows)
The swap-windows() function swaps the buffers between the two windows while the toogle-window-split() toogles between the vertical and horizontal split. I think I found the toogle-window-split() on StackOverflow and wrote the swap-windows() based on that.
;; Toggle buffer splits from vertical to horizontal
(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))))))
(define-key ctl-x-4-map "t" 'toggle-window-split)
