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 ;; Standard fringe bitmaps
  39
  40 (defconst no-fringe-bitmap 0)
  41 (defconst undef-fringe-bitmap 1)
  42 (defconst left-truncation-fringe-bitmap 2)
  43 (defconst right-truncation-fringe-bitmap 3)
  44 (defconst up-arrow-fringe-bitmap 4)
  45 (defconst down-arrow-fringe-bitmap 5)
  46 (defconst continued-line-fringe-bitmap 6)
  47 (defconst continuation-line-fringe-bitmap 7)
  48 (defconst overlay-arrow-fringe-bitmap 8)
  49 (defconst top-left-angle-fringe-bitmap 9)
  50 (defconst top-right-angle-fringe-bitmap 10)
  51 (defconst bottom-left-angle-fringe-bitmap 11)
  52 (defconst bottom-right-angle-fringe-bitmap 12)
  53 (defconst left-bracket-fringe-bitmap 13)
  54 (defconst right-bracket-fringe-bitmap 14)
  55 (defconst filled-box-cursor-fringe-bitmap 15)
  56 (defconst hollow-box-cursor-fringe-bitmap 16)
  57 (defconst hollow-square-fringe-bitmap 17)
  58 (defconst bar-cursor-fringe-bitmap 18)
  59 (defconst hbar-cursor-fringe-bitmap 19)
  60 (defconst empty-line-fringe-bitmap 20)
  61
  62
  63 ;; Control presence of fringes
  64
  65 (defvar fringe-mode)
  66
  67 (defun set-fringe-mode-1 (ignore value)
  68   "Call `set-fringe-mode' with VALUE.
  69 See `fringe-mode' for valid values and their effect.
  70 This is usually invoked when setting `fringe-mode' via customize."
  71   (set-fringe-mode value))
  72
  73 (defun set-fringe-mode (value)
  74   "Set `fringe-mode' to VALUE and put the new value into effect.
  75 See `fringe-mode' for possible values and their effect."
  76   (setq fringe-mode value)
  77
  78   ;; Apply it to default-frame-alist.
  79   (let ((parameter (assq 'left-fringe default-frame-alist)))
  80     (if (consp parameter)
  81         (setcdr parameter (if (consp fringe-mode)
  82                               (car fringe-mode)
  83                             fringe-mode))
  84       (setq default-frame-alist
  85             (cons (cons 'left-fringe (if (consp fringe-mode)
  86                                          (car fringe-mode)
  87                                        fringe-mode))
  88                   default-frame-alist))))
  89   (let ((parameter (assq 'right-fringe default-frame-alist)))
  90     (if (consp parameter)
  91         (setcdr parameter (if (consp fringe-mode)
  92                               (cdr fringe-mode)
  93                             fringe-mode))
  94       (setq default-frame-alist
  95             (cons (cons 'right-fringe (if (consp fringe-mode)
  96                                           (cdr fringe-mode)
  97                                         fringe-mode))
  98                   default-frame-alist))))
  99
 100   ;; Apply it to existing frames.
 101   (let ((frames (frame-list)))
 102     (while frames
 103       (modify-frame-parameters
 104        (car frames)
 105        (list (cons 'left-fringe (if (consp fringe-mode)
 106                                     (car fringe-mode)
 107                                   fringe-mode))
 108              (cons 'right-fringe (if (consp fringe-mode)
 109                                      (cdr fringe-mode)
 110                                    fringe-mode))))
 111       (setq frames (cdr frames)))))
 112
 113 ;;;###autoload
 114 (defcustom fringe-mode nil
 115   "*Specify appearance of fringes on all frames.
 116 This variable can be nil (the default) meaning the fringes should have
 117 the default width (8 pixels), it can be an integer value specifying
 118 the width of both left and right fringe (where 0 means no fringe), or
 119 a cons cell where car indicates width of left fringe and cdr indicates
 120 width of right fringe (where again 0 can be used to indicate no
 121 fringe).
 122 To set this variable in a Lisp program, use `set-fringe-mode' to make
 123 it take real effect.
 124 Setting the variable with a customization buffer also takes effect.
 125 If you only want to modify the appearance of the fringe in one frame,
 126 you can use the interactive function `toggle-fringe'"
 127   :type '(choice (const :tag "Default width" nil)
 128                  (const :tag "No fringes" 0)
 129                  (const :tag "Only right" (0 . nil))
 130                  (const :tag "Only left" (nil . 0))
 131                  (const :tag "Half width" (5 . 5))
 132                  (const :tag "Minimal" (1 . 1))
 133                  (integer :tag "Specific width")
 134                  (cons :tag "Different left/right sizes"
 135                        (integer :tag "Left width")
 136                        (integer :tag "Right width")))
 137   :group 'frames
 138   :require 'fringe
 139   :set 'set-fringe-mode-1)
 140
 141 (defun fringe-query-style (&optional all-frames)
 142   "Query user for fringe style.
 143 Returns values suitable for left-fringe and right-fringe frame parameters.
 144 If ALL-FRAMES, the negation of the fringe values in
 145 `default-frame-alist' is used when user enters the empty string.
 146 Otherwise the negation of the fringe value in the currently selected
 147 frame parameter is used."
 148   (let ((mode (intern (completing-read
 149                        "Select fringe mode for all frames (type ? for list): "
 150                        '(("none") ("default") ("left-only")
 151                          ("right-only") ("half") ("minimal"))
 152                        nil t))))
 153     (cond ((eq mode 'none) 0)
 154           ((eq mode 'default) nil)
 155           ((eq mode 'left-only) '(nil . 0))
 156           ((eq mode 'right-only) '(0 . nil))
 157           ((eq mode 'half) '(5 . 5))
 158           ((eq mode 'minimal) '(1 . 1))
 159           ((eq mode (intern ""))
 160            (if (eq 0 (cdr (assq 'left-fringe
 161                                 (if all-frames
 162                                     default-frame-alist
 163                                   (frame-parameters (selected-frame))))))
 164                nil
 165              0)))))
 166
 167 ;;;###autoload
 168 (defun fringe-mode (&optional mode)
 169   "Set the default appearance of fringes on all frames.
 170
 171 When called interactively, query the user for MODE.  Valid values
 172 for MODE include `none', `default', `left-only', `right-only',
 173 `minimal' and `half'.
 174
 175 When used in a Lisp program, MODE can be a cons cell where the
 176 integer in car specifies the left fringe width and the integer in
 177 cdr specifies the right fringe width.  MODE can also be a single
 178 integer that specifies both the left and the right fringe width.
 179 If a fringe width specification is nil, that means to use the
 180 default width (8 pixels).  This command may round up the left and
 181 right width specifications to ensure that their sum is a multiple
 182 of the character width of a frame.  It never rounds up a fringe
 183 width of 0.
 184
 185 Fringe widths set by `set-window-fringes' override the default
 186 fringe widths set by this command.  This command applies to all
 187 frames that exist and frames to be created in the future.  If you
 188 want to set the default appearance of fringes on the selected
 189 frame only, see the command `set-fringe-style'."
 190   (interactive (list (fringe-query-style 'all-frames)))
 191   (set-fringe-mode mode))
 192
 193 ;;;###autoload
 194 (defun set-fringe-style (&optional mode)
 195   "Set the default appearance of fringes on the selected frame.
 196
 197 When called interactively, query the user for MODE.  Valid values
 198 for MODE include `none', `default', `left-only', `right-only',
 199 `minimal' and `half'.
 200
 201 When used in a Lisp program, MODE can be a cons cell where the
 202 integer in car specifies the left fringe width and the integer in
 203 cdr specifies the right fringe width.  MODE can also be a single
 204 integer that specifies both the left and the right fringe width.
 205 If a fringe width specification is nil, that means to use the
 206 default width (8 pixels).  This command may round up the left and
 207 right width specifications to ensure that their sum is a multiple
 208 of the character width of a frame.  It never rounds up a fringe
 209 width of 0.
 210
 211 Fringe widths set by `set-window-fringes' override the default
 212 fringe widths set by this command.  If you want to set the
 213 default appearance of fringes on all frames, see the command
 214 `fringe-mode'."
 215   (interactive (list (fringe-query-style)))
 216   (modify-frame-parameters
 217    (selected-frame)
 218    (list (cons 'left-fringe (if (consp mode) (car mode) mode))
 219          (cons 'right-fringe (if (consp mode) (cdr mode) mode)))))
 220
 221 (defsubst fringe-columns (side &optional real)
 222   "Return the width, measured in columns, of the fringe area on SIDE.
 223 If optional argument REAL is non-nil, return a real floating point
 224 number instead of a rounded integer value.
 225 SIDE must be the symbol `left' or `right'."
 226   (funcall (if real '/ 'ceiling)
 227            (or (funcall (if (eq side 'left) 'car 'cadr)
 228                         (window-fringes))
 229                0)
 230            (float (frame-char-width))))
 231
 232 (provide 'fringe)
 233
 234 ;;; arch-tag: 6611ef60-0869-47ed-8b93-587ee7d3ff5d
 235 ;;; fringe.el ends here