lisp/fringe.el

   1 ;;; fringe.el --- fringe setup and control
   2
   3 ;; Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008 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 3, 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., 51 Franklin Street, Fifth Floor,
  24 ;; Boston, MA 02110-1301, USA.
  25
  26 ;;; Commentary:
  27
  28 ;; This file contains code to initialize the built-in fringe bitmaps
  29 ;; as well as helpful functions for customizing the appearance of the
  30 ;; fringe.
  31
  32 ;; The code is influenced by scroll-bar.el and avoid.el.  The author
  33 ;; gratefully acknowledge comments and suggestions made by Miles
  34 ;; Bader, Eli Zaretski, Richard Stallman, Pavel Janík and others which
  35 ;; improved this package.
  36
  37 ;;; Code:
  38
  39 (defgroup fringe nil
  40   "Window fringes."
  41   :version "22.1"
  42   :group 'frames)
  43
  44 ;; Define the built-in fringe bitmaps and setup default mappings
  45
  46 (when (boundp 'fringe-bitmaps)
  47   (let ((bitmaps '(question-mark
  48                    left-arrow right-arrow up-arrow down-arrow
  49                    left-curly-arrow right-curly-arrow
  50                    left-triangle right-triangle
  51                    top-left-angle top-right-angle
  52                    bottom-left-angle bottom-right-angle
  53                    left-bracket right-bracket
  54                    filled-rectangle hollow-rectangle
  55                    filled-square hollow-square
  56                    vertical-bar horizontal-bar
  57                    empty-line))
  58         (bn 1))
  59     (while bitmaps
  60       (push (car bitmaps) fringe-bitmaps)
  61       (put (car bitmaps) 'fringe bn)
  62       (setq bitmaps (cdr bitmaps)
  63             bn (1+ bn))))
  64
  65   (setq-default fringe-indicator-alist
  66                 '((truncation . (left-arrow right-arrow))
  67                   (continuation . (left-curly-arrow right-curly-arrow))
  68                   (overlay-arrow . right-triangle)
  69                   (up . up-arrow)
  70                   (down . down-arrow)
  71                   (top . (top-left-angle top-right-angle))
  72                   (bottom . (bottom-left-angle bottom-right-angle
  73                              top-right-angle top-left-angle))
  74                   (top-bottom . (left-bracket right-bracket
  75                                  top-right-angle top-left-angle))
  76                   (empty-line . empty-line)
  77                   (unknown . question-mark)))
  78
  79   (setq-default fringe-cursor-alist
  80                 '((box . filled-rectangle)
  81                   (hollow . hollow-rectangle)
  82                   (bar . vertical-bar)
  83                   (hbar . horizontal-bar)
  84                   (hollow-small . hollow-square))))
  85
  86
  87 (defmacro fringe-bitmap-p (symbol)
  88   "Return non-nil if SYMBOL is a fringe bitmap."
  89   `(get ,symbol 'fringe))
  90
  91
  92 ;; Control presence of fringes
  93
  94 (defvar fringe-mode)
  95
  96 (defun set-fringe-mode-1 (ignore value)
  97   "Call `set-fringe-mode' with VALUE.
  98 See `fringe-mode' for valid values and their effect.
  99 This is usually invoked when setting `fringe-mode' via customize."
 100   (set-fringe-mode value))
 101
 102 (defun set-fringe-mode (value)
 103   "Set `fringe-mode' to VALUE and put the new value into effect.
 104 See `fringe-mode' for possible values and their effect."
 105   (setq fringe-mode value)
 106
 107   ;; Apply it to default-frame-alist.
 108   (let ((parameter (assq 'left-fringe default-frame-alist)))
 109     (if (consp parameter)
 110         (setcdr parameter (if (consp fringe-mode)
 111                               (car fringe-mode)
 112                             fringe-mode))
 113       (setq default-frame-alist
 114             (cons (cons 'left-fringe (if (consp fringe-mode)
 115                                          (car fringe-mode)
 116                                        fringe-mode))
 117                   default-frame-alist))))
 118   (let ((parameter (assq 'right-fringe default-frame-alist)))
 119     (if (consp parameter)
 120         (setcdr parameter (if (consp fringe-mode)
 121                               (cdr fringe-mode)
 122                             fringe-mode))
 123       (setq default-frame-alist
 124             (cons (cons 'right-fringe (if (consp fringe-mode)
 125                                           (cdr fringe-mode)
 126                                         fringe-mode))
 127                   default-frame-alist))))
 128
 129   ;; Apply it to existing frames.
 130   (let ((frames (frame-list)))
 131     (while frames
 132       (modify-frame-parameters
 133        (car frames)
 134        (list (cons 'left-fringe (if (consp fringe-mode)
 135                                     (car fringe-mode)
 136                                   fringe-mode))
 137              (cons 'right-fringe (if (consp fringe-mode)
 138                                      (cdr fringe-mode)
 139                                    fringe-mode))))
 140       (setq frames (cdr frames)))))
 141
 142 ;; For initialization of fringe-mode, take account of changes
 143 ;; made explicitly to default-frame-alist.
 144 (defun fringe-mode-initialize (symbol value)
 145   (let* ((left-pair (assq 'left-fringe default-frame-alist))
 146          (right-pair (assq 'right-fringe default-frame-alist))
 147          (left (cdr left-pair))
 148          (right (cdr right-pair)))
 149     (if (or left-pair right-pair)
 150         ;; If there's something in default-frame-alist for fringes,
 151         ;; don't change it, but reflect that into the value of fringe-mode.
 152         (progn
 153           (setq fringe-mode (cons left right))
 154           (if (equal fringe-mode '(nil . nil))
 155               (setq fringe-mode nil))
 156           (if (equal fringe-mode '(0 . 0))
 157               (setq fringe-mode 0)))
 158       ;; Otherwise impose the user-specified value of fringe-mode.
 159       (custom-initialize-reset symbol value))))
 160
 161 (defcustom fringe-mode nil
 162   "*Specify appearance of fringes on all frames.
 163 This variable can be nil (the default) meaning the fringes should have
 164 the default width (8 pixels), it can be an integer value specifying
 165 the width of both left and right fringe (where 0 means no fringe), or
 166 a cons cell where car indicates width of left fringe and cdr indicates
 167 width of right fringe (where again 0 can be used to indicate no
 168 fringe).
 169 To set this variable in a Lisp program, use `set-fringe-mode' to make
 170 it take real effect.
 171 Setting the variable with a customization buffer also takes effect.
 172 If you only want to modify the appearance of the fringe in one frame,
 173 you can use the interactive function `set-fringe-style'."
 174   :type '(choice (const :tag "Default width" nil)
 175                  (const :tag "No fringes" 0)
 176                  (const :tag "Only right" (0 . nil))
 177                  (const :tag "Only left" (nil . 0))
 178                  (const :tag "Half width" (5 . 5))
 179                  (const :tag "Minimal" (1 . 1))
 180                  (integer :tag "Specific width")
 181                  (cons :tag "Different left/right sizes"
 182                        (integer :tag "Left width")
 183                        (integer :tag "Right width")))
 184   :group 'fringe
 185   :require 'fringe
 186   :initialize 'fringe-mode-initialize
 187   :set 'set-fringe-mode-1)
 188
 189 (defun fringe-query-style (&optional all-frames)
 190   "Query user for fringe style.
 191 Returns values suitable for left-fringe and right-fringe frame parameters.
 192 If ALL-FRAMES, the negation of the fringe values in
 193 `default-frame-alist' is used when user enters the empty string.
 194 Otherwise the negation of the fringe value in the currently selected
 195 frame parameter is used."
 196   (let ((mode (intern (completing-read
 197                        (concat
 198                         "Select fringe mode for "
 199                         (if all-frames "all frames" "selected frame")
 200                         " (type ? for list): ")
 201                        '(("none") ("default") ("left-only")
 202                          ("right-only") ("half") ("minimal"))
 203                        nil t))))
 204     (cond ((eq mode 'none) 0)
 205           ((eq mode 'default) nil)
 206           ((eq mode 'left-only) '(nil . 0))
 207           ((eq mode 'right-only) '(0 . nil))
 208           ((eq mode 'half) '(5 . 5))
 209           ((eq mode 'minimal) '(1 . 1))
 210           ((eq mode (intern ""))
 211            (if (eq 0 (cdr (assq 'left-fringe
 212                                 (if all-frames
 213                                     default-frame-alist
 214                                   (frame-parameters (selected-frame))))))
 215                nil
 216              0)))))
 217
 218 (defun fringe-mode (&optional mode)
 219   "Set the default appearance of fringes on all frames.
 220
 221 When called interactively, query the user for MODE.  Valid values
 222 for MODE include `none', `default', `left-only', `right-only',
 223 `minimal' and `half'.
 224
 225 When used in a Lisp program, MODE can be a cons cell where the
 226 integer in car specifies the left fringe width and the integer in
 227 cdr specifies the right fringe width.  MODE can also be a single
 228 integer that specifies both the left and the right fringe width.
 229 If a fringe width specification is nil, that means to use the
 230 default width (8 pixels).  This command may round up the left and
 231 right width specifications to ensure that their sum is a multiple
 232 of the character width of a frame.  It never rounds up a fringe
 233 width of 0.
 234
 235 Fringe widths set by `set-window-fringes' override the default
 236 fringe widths set by this command.  This command applies to all
 237 frames that exist and frames to be created in the future.  If you
 238 want to set the default appearance of fringes on the selected
 239 frame only, see the command `set-fringe-style'."
 240   (interactive (list (fringe-query-style 'all-frames)))
 241   (set-fringe-mode mode))
 242
 243 (defun set-fringe-style (&optional mode)
 244   "Set the default appearance of fringes on the selected frame.
 245
 246 When called interactively, query the user for MODE.  Valid values
 247 for MODE include `none', `default', `left-only', `right-only',
 248 `minimal' and `half'.
 249
 250 When used in a Lisp program, MODE can be a cons cell where the
 251 integer in car specifies the left fringe width and the integer in
 252 cdr specifies the right fringe width.  MODE can also be a single
 253 integer that specifies both the left and the right fringe width.
 254 If a fringe width specification is nil, that means to use the
 255 default width (8 pixels).  This command may round up the left and
 256 right width specifications to ensure that their sum is a multiple
 257 of the character width of a frame.  It never rounds up a fringe
 258 width of 0.
 259
 260 Fringe widths set by `set-window-fringes' override the default
 261 fringe widths set by this command.  If you want to set the
 262 default appearance of fringes on all frames, see the command
 263 `fringe-mode'."
 264   (interactive (list (fringe-query-style)))
 265   (modify-frame-parameters
 266    (selected-frame)
 267    (list (cons 'left-fringe (if (consp mode) (car mode) mode))
 268          (cons 'right-fringe (if (consp mode) (cdr mode) mode)))))
 269
 270 (defsubst fringe-columns (side &optional real)
 271   "Return the width, measured in columns, of the fringe area on SIDE.
 272 If optional argument REAL is non-nil, return a real floating point
 273 number instead of a rounded integer value.
 274 SIDE must be the symbol `left' or `right'."
 275   (funcall (if real '/ 'ceiling)
 276            (or (funcall (if (eq side 'left) 'car 'cadr)
 277                         (window-fringes))
 278                0)
 279            (float (frame-char-width))))
 280
 281 (provide 'fringe)
 282
 283 ;;; arch-tag: 6611ef60-0869-47ed-8b93-587ee7d3ff5d
 284 ;;; fringe.el ends here