Toggle full view of window in Emacs

Add below code into your ~/.emacs:

(defun toggle-full-window()
  "Toggle the full view of selected window"
  (interactive)
  ;; @see http://www.gnu.org/software/emacs/manual/html_node/elisp/Splitting-Windows.html
  (if (window-parent)
      (delete-other-windows)
    (winner-undo)
    ))

I use evil, so I assign hot key ",ff" to `toggle-full-window`.