lisp/fringe.el

   1 ;;; fringe.el --- change fringes appearance in various ways
   2
   3 ;; Copyright (C) 2002, 2003 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 ;;;###autoload
  87 (defcustom fringe-mode nil
  88   "*Specify appearance of fringes on all frames.
  89 This variable can be nil (the default) meaning the fringes should have
  90 the default width (8 pixels), it can be an integer value specifying
  91 the width of both left and right fringe (where 0 means no fringe), or
  92 a cons cell where car indicates width of left fringe and cdr indicates
  93 width of right fringe (where again 0 can be used to indicate no
  94 fringe).
  95 To set this variable in a Lisp program, use `set-fringe-mode' to make
  96 it take real effect.
  97 Setting the variable with a customization buffer also takes effect.
  98 If you only want to modify the appearance of the fringe in one frame,
  99 you can use the interactive function `toggle-fringe'"
 100   :type '(choice (const :tag "Default width" nil)
 101                  (const :tag "No fringes" 0)
 102                  (const :tag "Only right" (0 . nil))
 103                  (const :tag "Only left" (nil . 0))
 104                  (const :tag "Half width" (5 . 5))
 105                  (const :tag "Minimal" (1 . 1))
 106                  (integer :tag "Specific width")
 107                  (cons :tag "Different left/right sizes"
 108                        (integer :tag "Left width")
 109                        (integer :tag "Right width")))
 110   :group 'frames
 111   :require 'fringe
 112   :set 'set-fringe-mode-1)
 113
 114 (defun fringe-query-style (&optional all-frames)
 115   "Query user for fringe style.
 116 Returns values suitable for left-fringe and right-fringe frame parameters.
 117 If ALL-FRAMES, the negation of the fringe values in
 118 `default-frame-alist' is used when user enters the empty string.
 119 Otherwise the negation of the fringe value in the currently selected
 120 frame parameter is used."
 121   (let ((mode (intern (completing-read
 122                        "Select fringe mode for all frames (SPACE for list): "
 123                        '(("none") ("default") ("left-only")
 124                          ("right-only") ("half") ("minimal"))
 125                        nil t))))
 126     (cond ((eq mode 'none) 0)
 127           ((eq mode 'default) nil)
 128           ((eq mode 'left-only) '(nil . 0))
 129           ((eq mode 'right-only) '(0 . nil))
 130           ((eq mode 'half) '(5 . 5))
 131           ((eq mode 'minimal) '(1 . 1))
 132           ((eq mode (intern ""))
 133            (if (eq 0 (cdr (assq 'left-fringe
 134                                 (if all-frames
 135                                     default-frame-alist
 136                                   (frame-parameters (selected-frame))))))
 137                nil
 138              0)))))
 139
 140 ;;;###autoload
 141 (defun fringe-mode (&optional mode)
 142   "Set the default appearance of fringes on all frames.
 143
 144 When called interactively, query the user for MODE.  Valid values
 145 for MODE include `none', `default', `left-only', `right-only',
 146 `minimal' and `half'.
 147
 148 When used in a Lisp program, MODE can be a cons cell where the
 149 integer in car specifies the left fringe width and the integer in
 150 cdr specifies the right fringe width.  MODE can also be a single
 151 integer that specifies both the left and the right fringe width.
 152 If a fringe width specification is nil, that means to use the
 153 default width (8 pixels).  This command may round up the left and
 154 right width specifications to ensure that their sum is a multiple
 155 of the character width of a frame.  It never rounds up a fringe
 156 width of 0.
 157
 158 Fringe widths set by `set-window-fringes' override the default
 159 fringe widths set by this command.  This command applies to all
 160 frames that exist and frames to be created in the future.  If you
 161 want to set the default appearance of fringes on the selected
 162 frame only, see the command `set-fringe-style'."
 163   (interactive (list (fringe-query-style 'all-frames)))
 164   (set-fringe-mode mode))
 165
 166 ;;;###autoload
 167 (defun set-fringe-style (&optional mode)
 168   "Set the default appearance of fringes on the selected frame.
 169
 170 When called interactively, query the user for MODE.  Valid values
 171 for MODE include `none', `default', `left-only', `right-only',
 172 `minimal' and `half'.
 173
 174 When used in a Lisp program, MODE can be a cons cell where the
 175 integer in car specifies the left fringe width and the integer in
 176 cdr specifies the right fringe width.  MODE can also be a single
 177 integer that specifies both the left and the right fringe width.
 178 If a fringe width specification is nil, that means to use the
 179 default width (8 pixels).  This command may round up the left and
 180 right width specifications to ensure that their sum is a multiple
 181 of the character width of a frame.  It never rounds up a fringe
 182 width of 0.
 183
 184 Fringe widths set by `set-window-fringes' override the default
 185 fringe widths set by this command.  If you want to set the
 186 default appearance of fringes on all frames, see the command
 187 `fringe-mode'."
 188   (interactive (list (fringe-query-style)))
 189   (modify-frame-parameters
 190    (selected-frame)
 191    (list (cons 'left-fringe (if (consp mode) (car mode) mode))
 192          (cons 'right-fringe (if (consp mode) (cdr mode) mode)))))
 193
 194 (provide 'fringe)
 195
 196 ;;; arch-tag: 6611ef60-0869-47ed-8b93-587ee7d3ff5d
 197 ;;; fringe.el ends here