lisp/disp-table.el

   1 ;;; disp-table.el --- functions for dealing with char tables
   2
   3 ;; Copyright (C) 1987, 1994-1995, 1999, 2001-2011
   4 ;;   Free Software Foundation, Inc.
   5
   6 ;; Author: Erik Naggum <erik@naggum.no>
   7 ;; Based on a previous version by Howard Gayle
   8 ;; Maintainer: FSF
   9 ;; Keywords: i18n
  10 ;; Package: emacs
  11
  12 ;; This file is part of GNU Emacs.
  13
  14 ;; GNU Emacs is free software: you can redistribute it and/or modify
  15 ;; it under the terms of the GNU General Public License as published by
  16 ;; the Free Software Foundation, either version 3 of the License, or
  17 ;; (at your option) any later version.
  18
  19 ;; GNU Emacs is distributed in the hope that it will be useful,
  20 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  21 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22 ;; GNU General Public License for more details.
  23
  24 ;; You should have received a copy of the GNU General Public License
  25 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  26
  27 ;;; Commentary:
  28
  29 ;;; Code:
  30
  31 (put 'display-table 'char-table-extra-slots 6)
  32
  33 ;;;###autoload
  34 (defun make-display-table ()
  35   "Return a new, empty display table."
  36   (make-char-table 'display-table nil))
  37
  38 (or standard-display-table
  39     (setq standard-display-table (make-display-table)))
  40
  41 ;;; Display-table slot names.  The property value says which slot.
  42
  43 (put 'truncation 'display-table-slot 0)
  44 (put 'wrap 'display-table-slot 1)
  45 (put 'escape 'display-table-slot 2)
  46 (put 'control 'display-table-slot 3)
  47 (put 'selective-display 'display-table-slot 4)
  48 (put 'vertical-border 'display-table-slot 5)
  49
  50 ;;;###autoload
  51 (defun display-table-slot (display-table slot)
  52   "Return the value of the extra slot in DISPLAY-TABLE named SLOT.
  53 SLOT may be a number from 0 to 5 inclusive, or a slot name (symbol).
  54 Valid symbols are `truncation', `wrap', `escape', `control',
  55 `selective-display', and `vertical-border'."
  56   (let ((slot-number
  57          (if (numberp slot) slot
  58            (or (get slot 'display-table-slot)
  59                (error "Invalid display-table slot name: %s" slot)))))
  60     (char-table-extra-slot display-table slot-number)))
  61
  62 ;;;###autoload
  63 (defun set-display-table-slot (display-table slot value)
  64   "Set the value of the extra slot in DISPLAY-TABLE named SLOT to VALUE.
  65 SLOT may be a number from 0 to 5 inclusive, or a name (symbol).
  66 Valid symbols are `truncation', `wrap', `escape', `control',
  67 `selective-display', and `vertical-border'."
  68   (let ((slot-number
  69          (if (numberp slot) slot
  70            (or (get slot 'display-table-slot)
  71                (error "Invalid display-table slot name: %s" slot)))))
  72     (set-char-table-extra-slot display-table slot-number value)))
  73
  74 ;;;###autoload
  75 (defun describe-display-table (dt)
  76   "Describe the display table DT in a help buffer."
  77   (with-help-window "*Help*"
  78     (princ "\nTruncation glyph: ")
  79     (prin1 (display-table-slot dt 'truncation))
  80     (princ "\nWrap glyph: ")
  81     (prin1 (display-table-slot dt 'wrap))
  82     (princ "\nEscape glyph: ")
  83     (prin1 (display-table-slot dt 'escape))
  84     (princ "\nCtrl glyph: ")
  85     (prin1 (display-table-slot dt 'control))
  86     (princ "\nSelective display glyph sequence: ")
  87     (prin1 (display-table-slot dt 'selective-display))
  88     (princ "\nVertical window border glyph: ")
  89     (prin1 (display-table-slot dt 'vertical-border))
  90     (princ "\nCharacter display glyph sequences:\n")
  91     (with-current-buffer standard-output
  92       (let ((vector (make-vector 256 nil))
  93             (i 0))
  94         (while (< i 256)
  95           (aset vector i (aref dt i))
  96           (setq i (1+ i)))
  97         (describe-vector vector))
  98       (help-mode))))
  99
 100 ;;;###autoload
 101 (defun describe-current-display-table ()
 102   "Describe the display table in use in the selected window and buffer."
 103   (interactive)
 104   (let ((disptab (or (window-display-table (selected-window))
 105                      buffer-display-table
 106                      standard-display-table)))
 107     (if disptab
 108         (describe-display-table disptab)
 109       (message "No display table"))))
 110
 111 ;;;###autoload
 112 (defun standard-display-8bit (l h)
 113   "Display characters representing raw bytes in the range L to H literally.
 114
 115 On a terminal display, each character in the range is displayed
 116 by sending the corresponding byte directly to the terminal.
 117
 118 On a graphic display, each character in the range is displayed
 119 using the default font by a glyph whose code is the corresponding
 120 byte.
 121
 122 Note that ASCII printable characters (SPC to TILDA) are displayed
 123 in the default way after this call."
 124   (or standard-display-table
 125       (setq standard-display-table (make-display-table)))
 126   (if (> h 255)
 127       (setq h 255))
 128   (while (<= l h)
 129     (if (< l 128)
 130         (aset standard-display-table l
 131               (if (or (< l ?\s) (= l 127)) (vector l)))
 132       (let ((c (unibyte-char-to-multibyte l)))
 133         (aset standard-display-table c (vector c))))
 134     (setq l (1+ l))))
 135
 136 ;;;###autoload
 137 (defun standard-display-default (l h)
 138   "Display characters in the range L to H using the default notation."
 139   (or standard-display-table
 140       (setq standard-display-table (make-display-table)))
 141   (while (<= l h)
 142     (if (and (>= l ?\s) (characterp l))
 143         (aset standard-display-table l nil))
 144     (setq l (1+ l))))
 145
 146 ;; This function does NOT take terminal-dependent escape sequences.
 147 ;; For that, you need to go through create-glyph.  Use one of the
 148 ;; other functions below, or roll your own.
 149 ;;;###autoload
 150 (defun standard-display-ascii (c s)
 151   "Display character C using printable string S."
 152   (or standard-display-table
 153       (setq standard-display-table (make-display-table)))
 154   (aset standard-display-table c (vconcat s)))
 155
 156 ;;;###autoload
 157 (defun standard-display-g1 (c sc)
 158   "Display character C as character SC in the g1 character set.
 159 This function assumes that your terminal uses the SO/SI characters;
 160 it is meaningless for an X frame."
 161   (if (memq window-system '(x w32 ns))
 162       (error "Cannot use string glyphs in a windowing system"))
 163   (or standard-display-table
 164       (setq standard-display-table (make-display-table)))
 165   (aset standard-display-table c
 166         (vector (create-glyph (concat "\016" (char-to-string sc) "\017")))))
 167
 168 ;;;###autoload
 169 (defun standard-display-graphic (c gc)
 170   "Display character C as character GC in graphics character set.
 171 This function assumes VT100-compatible escapes; it is meaningless for an
 172 X frame."
 173   (if (memq window-system '(x w32 ns))
 174       (error "Cannot use string glyphs in a windowing system"))
 175   (or standard-display-table
 176       (setq standard-display-table (make-display-table)))
 177   (aset standard-display-table c
 178         (vector (create-glyph (concat "\e(0" (char-to-string gc) "\e(B")))))
 179
 180 ;;;###autoload
 181 (defun standard-display-underline (c uc)
 182   "Display character C as character UC plus underlining."
 183   (or standard-display-table
 184       (setq standard-display-table (make-display-table)))
 185   (aset standard-display-table c
 186         (vector
 187          (if window-system
 188              (make-glyph-code uc 'underline)
 189            (create-glyph (concat "\e[4m" (char-to-string uc) "\e[m"))))))
 190
 191 ;;;###autoload
 192 (defun create-glyph (string)
 193   "Allocate a glyph code to display by sending STRING to the terminal."
 194   (if (= (length glyph-table) 65536)
 195       (error "No free glyph codes remain"))
 196   ;; Don't use slots that correspond to ASCII characters.
 197   (if (= (length glyph-table) 32)
 198       (setq glyph-table (vconcat glyph-table (make-vector 224 nil))))
 199   (setq glyph-table (vconcat glyph-table (list string)))
 200   (1- (length glyph-table)))
 201
 202 ;;;###autoload
 203 (defun make-glyph-code (char &optional face)
 204   "Return a glyph code representing char CHAR with face FACE."
 205   ;; Due to limitations on Emacs integer values, faces with
 206   ;; face id greater that 512 are silently ignored.
 207   (if (not face)
 208       char
 209     (let ((fid (face-id face)))
 210       (if (< fid 64) ; we have 32 - 3(LSB) - 1(SIGN) - 22(CHAR) = 6 bits for face id
 211           (logior char (lsh fid 22))
 212         (cons char fid)))))
 213
 214 ;;;###autoload
 215 (defun glyph-char (glyph)
 216   "Return the character of glyph code GLYPH."
 217   (if (consp glyph)
 218       (car glyph)
 219     (logand glyph #x3fffff)))
 220
 221 ;;;###autoload
 222 (defun glyph-face (glyph)
 223   "Return the face of glyph code GLYPH, or nil if glyph has default face."
 224   (let ((face-id (if (consp glyph) (cdr glyph) (lsh glyph -22))))
 225     (and (> face-id 0)
 226          (catch 'face
 227            (dolist (face (face-list))
 228              (when (eq (face-id face) face-id)
 229                (throw 'face face)))))))
 230
 231 ;;;###autoload
 232 (defun standard-display-european (arg)
 233   "Semi-obsolete way to toggle display of ISO 8859 European characters.
 234
 235 This function is semi-obsolete; you probably don't need it, or else you
 236 probably should use `set-language-environment' or `set-locale-environment'.
 237
 238 This function enables European character display if ARG is positive,
 239 disables it if negative.  Otherwise, it toggles European character display.
 240
 241 When this mode is enabled, characters in the range of 160 to 255
 242 display not as octal escapes, but as accented characters.  Codes 146
 243 and 160 display as apostrophe and space, even though they are not the
 244 ASCII codes for apostrophe and space.
 245
 246 Enabling European character display with this command noninteractively
 247 from Lisp code also selects Latin-1 as the language environment.
 248 This provides increased compatibility for users who call this function
 249 in `.emacs'."
 250
 251   (if (or (<= (prefix-numeric-value arg) 0)
 252           (and (null arg)
 253                (char-table-p standard-display-table)
 254                ;; Test 161, because 160 displays as a space.
 255                (equal (aref standard-display-table
 256                             (unibyte-char-to-multibyte 161))
 257                       (vector (unibyte-char-to-multibyte 161)))))
 258       (progn
 259         (standard-display-default
 260          (unibyte-char-to-multibyte 160) (unibyte-char-to-multibyte 255))
 261         (unless (or (memq window-system '(x w32 ns)))
 262           (and (terminal-coding-system)
 263                (set-terminal-coding-system nil))))
 264
 265     (display-warning 'i18n
 266                      "`standard-display-european' is semi-obsolete; see its doc string for details"
 267                      :warning)
 268
 269     ;; Switch to Latin-1 language environment
 270     ;; unless some other has been specified.
 271     (if (equal current-language-environment "English")
 272         (set-language-environment "latin-1"))
 273     (unless (or noninteractive (memq window-system '(x w32 ns)))
 274       ;; Send those codes literally to a character-based terminal.
 275       ;; If we are using single-byte characters,
 276       ;; it doesn't matter which coding system we use.
 277       (set-terminal-coding-system
 278        (let ((c (intern (downcase current-language-environment))))
 279          (if (coding-system-p c) c 'latin-1))))
 280     (standard-display-european-internal)))
 281
 282 (provide 'disp-table)
 283
 284 ;;; disp-table.el ends here