;;; vt-control.el --- Common VTxxx control functions
;; Copyright (C) 1993, 1994 Free Software Foundation, Inc.
;; Author: Rob Riepel <firstname.lastname@example.org>
;; Maintainer: Rob Riepel <email@example.com>
;; Keywords: terminals
;; This file is part of GNU Emacs.
;; GNU Emacs 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 2, or (at your option)
;; any later version.
;; GNU Emacs 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 GNU Emacs; see the file COPYING. If not, write to
;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
;; The functions contained in this file send various VT control codes
;; to the terminal where emacs is running. The following functions are
;; Function Action
;; vt-wide set wide screen (132 characters)
;; vt-narrow set narrow screen (80 characters)
;; vt-toggle-screen toggle wide/narrow screen
;; vt-keypad-on set applications keypad on
;; vt-keypad-off set applications keypad off
;; vt-numlock toggle applications keypad on/off
;; To use enable these functions, simply load this file.
;; Note: vt-control makes no effort to determine how the terminal is
;; initially set. It assumes the terminal starts with a width
;; of 80 characters and the applications keypad enabled. Nor
;; does vt-control try to restore the terminal when emacs is
;; killed or suspended.
;;; Global variables
(defvar vt-applications-keypad-p t
"If non-nil, keypad is in applications mode.")
(defvar vt-wide-p nil
"If non-nil, the screen is 132 characters wide.")
;;; Screen width functions.
(defun vt-wide nil
"Set the screen 132 characters wide."
(setq vt-wide-p t))
(defun vt-narrow nil
"Set the screen 80 characters wide."
(setq vt-wide-p nil))
(defun vt-toggle-screen nil
"Toggle between 80 and 132 character screen width."
(if vt-wide-p (vt-narrow) (vt-wide)))
;;; Applications keypad functions.
(defun vt-keypad-on (&optional tell)
"Turn on the VT applications keypad."
(setq vt-applications-keypad-p t)
(if (or tell (interactive-p)) (message "Applications keypad enabled.")))
(defun vt-keypad-off (&optional tell)
"Turn off the VT applications keypad."
(setq vt-applications-keypad-p nil)
(if (or tell (interactive-p)) (message "Applications keypad disabled.")))
(defun vt-numlock nil
"Toggle VT application keypad on and off."
(if vt-applications-keypad-p (vt-keypad-off (interactive-p))
;;; vt-control.el ends here