lisp/fringe.el

   1 ;;; fringe.el --- change fringes appearance in various ways
   2
   3 ;; Copyright (C) 2002 Free Software Foundation, Inc.
   4
   5 ;; Author: Simon Josefsson <simon@josefsson.org>
   6 ;; Maintainer: FSF
   7 ;; Keywords: frames
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software; you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation; either version 2, or (at your option)
  14 ;; any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  23 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  24 ;; Boston, MA 02111-1307, USA.
  25
  26 ;;; Commentary:
  27
  28 ;; This file contains helpful functions for customizing the appearance
  29 ;; of the fringe.
  30
  31 ;; The code is influenced by scroll-bar.el and avoid.el.  The author
  32 ;; gratefully acknowledge comments and suggestions made by Miles
  33 ;; Bader, Eli Zaretski, Richard Stallman, Pavel Janík and others which
  34 ;; improved this package.
  35
  36 ;;; Code:
  37
  38 (defvar fringe-mode)
  39
  40 (defun set-fringe-mode-1 (ignore value)
  41   "Call `set-fringe-mode' with VALUE.
  42 See `fringe-mode' for valid values and their effect.
  43 This is usually invoked when setting `fringe-mode' via customize."
  44   (set-fringe-mode value))
  45
  46 (defun set-fringe-mode (value)
  47   "Set `fringe-mode' to VALUE and put the new value into effect.
  48 See `fringe-mode' for possible values and their effect."
  49   (setq fringe-mode value)
  50
  51   ;; Apply it to default-frame-alist.
  52   (let ((parameter (assq 'left-fringe default-frame-alist)))
  53     (if (consp parameter)
  54         (setcdr parameter (if (consp fringe-mode)
  55                               (car fringe-mode)
  56                             fringe-mode))
  57       (setq default-frame-alist
  58             (cons (cons 'left-fringe (if (consp fringe-mode)
  59                                          (car fringe-mode)
  60                                        fringe-mode))
  61                   default-frame-alist))))
  62   (let ((parameter (assq 'right-fringe default-frame-alist)))
  63     (if (consp parameter)
  64         (setcdr parameter (if (consp fringe-mode)
  65                               (cdr fringe-mode)
  66                             fringe-mode))
  67       (setq default-frame-alist
  68             (cons (cons 'right-fringe (if (consp fringe-mode)
  69                                           (cdr fringe-mode)
  70                                         fringe-mode))
  71                   default-frame-alist))))
  72
  73   ;; Apply it to existing frames.
  74   (let ((frames (frame-list)))
  75     (while frames
  76       (modify-frame-parameters
  77        (car frames)
  78        (list (cons 'left-fringe (if (consp fringe-mode)
  79                                     (car fringe-mode)
  80                                   fringe-mode))
  81              (cons 'right-fringe (if (consp fringe-mode)
  82                                      (cdr fringe-mode)
  83                                    fringe-mode))))
  84       (setq frames (cdr frames)))))
  85
  86 (defcustom fringe-mode nil
  87   "*Specify appearance of fringes on all frames.
  88 This variable can be nil (the default) meaning the fringes should have
  89 the default width (8 pixels), it can be an integer value specifying
  90 the width of both left and right fringe (where 0 means no fringe), or
  91 a cons cell where car indicates width of left fringe and cdr indicates
  92 width of right fringe (where again 0 can be used to indicate no
  93 fringe).
  94 To set this variable in a Lisp program, use `set-fringe-mode' to make
  95 it take real effect.
  96 Setting the variable with a customization buffer also takes effect.
  97 If you only want to modify the appearance of the fringe in one frame,
  98 you can use the interactive function `toggle-fringe'"
  99   :type '(choice (const :tag "Default width" nil)
 100                  (const :tag "No fringes" 0)
 101                  (const :tag "Only right" (0 . nil))
 102                  (const :tag "Only left" (nil . 0))
 103                  (const :tag "Half width" (5 . 5))
 104                  (const :tag "Minimal" (1 . 1))
 105                  (integer :tag "Specific width")
 106                  (cons :tag "Different left/right sizes"
 107                        (integer :tag "Left width")
 108                        (integer :tag "Right width")))
 109   :group 'frames
 110   :require 'fringe
 111   :set 'set-fringe-mode-1)
 112
 113 (defun fringe-query-style (&optional all-frames)
 114   "Query user for fringe style.
 115 Returns values suitable for left-fringe and right-fringe frame parameters.
 116 If ALL-FRAMES, the negation of the fringe values in
 117 `default-frame-alist' is used when user enters the empty string.
 118 Otherwise the negation of the fringe value in the currently selected
 119 frame parameter is used."
 120   (let ((mode (intern (completing-read
 121                        "Select fringe mode for all frames (SPACE for list): "
 122                        '(("none") ("default") ("left-only")
 123                          ("right-only") ("half") ("minimal"))
 124                        nil t))))
 125     (cond ((eq mode 'none) 0)
 126           ((eq mode 'default) nil)
 127           ((eq mode 'left-only) '(nil . 0))
 128           ((eq mode 'right-only) '(0 . nil))
 129           ((eq mode 'half) '(5 . 5))
 130           ((eq mode 'minimal) '(1 . 1))
 131           ((eq mode (intern ""))
 132            (if (eq 0 (cdr (assq 'left-fringe
 133                                 (if all-frames
 134                                     default-frame-alist
 135                                   (frame-parameters (selected-frame))))))
 136                nil
 137              0)))))
 138
 139 ;;;###autoload
 140 (defun fringe-mode (&optional mode)
 141   "Toggle appearance of fringes on all frames.
 142 Valid values for MODE include `none', `default', `left-only',
 143 `right-only', `minimal' and `half'.  MODE can also be a cons cell
 144 where the integer in car will be used as left fringe width and the
 145 integer in cdr will be used as right fringe width. If MODE is not
 146 specified, the user is queried.
 147 It applies to all frames that exist and frames to be created in the
 148 future.
 149 If you want to set appearance of fringes on the selected frame only,
 150 see `set-fringe-style'."
 151   (interactive (list (fringe-query-style 'all-frames)))
 152   (set-fringe-mode mode))
 153
 154 ;;;###autoload
 155 (defun set-fringe-style (&optional mode)
 156   "Set appearance of fringes on selected frame.
 157 Valid values for MODE include `none', `default', `left-only',
 158 `right-only', `minimal' and `half'.  MODE can also be a cons cell
 159 where the integer in car will be used as left fringe width and the
 160 integer in cdr will be used as right fringe width. If MODE is not
 161 specified, the user is queried.
 162 If you want to set appearance of fringes on all frames, see `fringe-mode'."
 163   (interactive (list (fringe-query-style)))
 164   (modify-frame-parameters
 165    (selected-frame)
 166    (list (cons 'left-fringe (if (consp mode) (car mode) mode))
 167          (cons 'right-fringe (if (consp mode) (cdr mode) mode)))))
 168
 169 (provide 'fringe)
 170
 171 ;;; fringe.el ends here