lisp/textmodes/picture.el

   1 ;;; picture.el --- "Picture mode" -- editing using quarter-plane screen model
   2
   3 ;; Copyright (C) 1985, 1994 Free Software Foundation, Inc.
   4
   5 ;; Author: K. Shane Hartman
   6 ;; Maintainer: FSF
   7 ;; Keywords: convenience wp
   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 code provides the picture-mode commands documented in the Emacs
  29 ;; manual.  The screen is treated as a semi-infinite quarter-plane with
  30 ;; support for rectangle operations and `etch-a-sketch' character
  31 ;; insertion in any of eight directions.
  32
  33 ;;; Code:
  34
  35 (defgroup picture nil
  36   "Picture mode --- editing using quarter-plane screen model."
  37   :prefix "picture-"
  38   :group 'editing)
  39
  40 (defcustom picture-rectangle-ctl ?+
  41   "*Character `picture-draw-rectangle' uses for top left corners."
  42   :type 'character
  43   :group 'picture)
  44 (defcustom picture-rectangle-ctr ?+
  45   "*Character `picture-draw-rectangle' uses for top right corners."
  46   :type 'character
  47   :group 'picture)
  48 (defcustom picture-rectangle-cbr ?+
  49   "*Character `picture-draw-rectangle' uses for bottom right corners."
  50   :type 'character
  51   :group 'picture)
  52 (defcustom picture-rectangle-cbl ?+
  53   "*Character `picture-draw-rectangle' uses for bottom left corners."
  54   :type 'character
  55   :group 'picture)
  56 (defcustom picture-rectangle-v   ?|
  57   "*Character `picture-draw-rectangle' uses for vertical lines."
  58   :type 'character
  59   :group 'picture)
  60 (defcustom picture-rectangle-h   ?-
  61   "*Character `picture-draw-rectangle' uses for horizontal lines."
  62   :type 'character
  63   :group 'picture)
  64
  65
  66 ;; Picture Movement Commands
  67
  68 ;; When a cursor is on a wide-column character (e.g. Chinese,
  69 ;; Japanese, Korean), this variable tells the desired current column
  70 ;; which may be different from (current-column).
  71 (defvar picture-desired-column 0)
  72
  73 ;; If the value of picture-desired-column is far from the current
  74 ;; column, or if the arg ADJUST-TO-CURRENT is non-nil, set it to the
  75 ;; current column.   Return the current column.
  76 (defun picture-update-desired-column (adjust-to-current)
  77   (let ((current-column (current-column)))
  78     (if (or adjust-to-current
  79             (< picture-desired-column (1- current-column))
  80             (> picture-desired-column (1+ current-column)))
  81         (setq picture-desired-column current-column))
  82     current-column))
  83
  84 (defun picture-beginning-of-line (&optional arg)
  85   "Position point at the beginning of the line.
  86 With ARG not nil, move forward ARG - 1 lines first.
  87 If scan reaches end of buffer, stop there without error."
  88   (interactive "P")
  89   (if arg (forward-line (1- (prefix-numeric-value arg))))
  90   (beginning-of-line)
  91   (setq picture-desired-column 0))
  92
  93 (defun picture-end-of-line (&optional arg)
  94   "Position point after last non-blank character on current line.
  95 With ARG not nil, move forward ARG - 1 lines first.
  96 If scan reaches end of buffer, stop there without error."
  97   (interactive "P")
  98   (if arg (forward-line (1- (prefix-numeric-value arg))))
  99   (beginning-of-line)
 100   (skip-chars-backward " \t" (prog1 (point) (end-of-line)))
 101   (setq picture-desired-column (current-column)))
 102
 103 (defun picture-forward-column (arg)
 104   "Move cursor right, making whitespace if necessary.
 105 With argument, move that many columns."
 106   (interactive "p")
 107   (picture-update-desired-column (interactive-p))
 108   (setq picture-desired-column (max 0 (+ picture-desired-column arg)))
 109   (let ((current-column (move-to-column picture-desired-column t)))
 110     (if (and (> current-column picture-desired-column)
 111              (< arg 0))
 112         ;; It seems that we have just tried to move to the right
 113         ;; column of a multi-column character.
 114         (forward-char -1))))
 115
 116 (defun picture-backward-column (arg)
 117   "Move cursor left, making whitespace if necessary.
 118 With argument, move that many columns."
 119   (interactive "p")
 120   (picture-update-desired-column (interactive-p))
 121   (picture-forward-column (- arg)))
 122
 123 (defun picture-move-down (arg)
 124   "Move vertically down, making whitespace if necessary.
 125 With argument, move that many lines."
 126   (interactive "p")
 127   (picture-update-desired-column nil)
 128   (picture-newline arg)
 129   (let ((current-column (move-to-column picture-desired-column t)))
 130     (if (> current-column picture-desired-column)
 131         (forward-char -1))))
 132
 133 (defvar picture-vertical-step 0
 134   "Amount to move vertically after text character in Picture mode.")
 135
 136 (defvar picture-horizontal-step 1
 137   "Amount to move horizontally after text character in Picture mode.")
 138
 139 (defun picture-move-up (arg)
 140   "Move vertically up, making whitespace if necessary.
 141 With argument, move that many lines."
 142   (interactive "p")
 143   (picture-update-desired-column nil)
 144   (picture-move-down (- arg)))
 145
 146 (defun picture-movement-right ()
 147   "Move right after self-inserting character in Picture mode."
 148   (interactive)
 149   (picture-set-motion 0 1))
 150
 151 (defun picture-movement-left ()
 152   "Move left after self-inserting character in Picture mode."
 153   (interactive)
 154   (picture-set-motion 0 -1))
 155
 156 (defun picture-movement-up ()
 157   "Move up after self-inserting character in Picture mode."
 158   (interactive)
 159   (picture-set-motion -1 0))
 160
 161 (defun picture-movement-down ()
 162   "Move down after self-inserting character in Picture mode."
 163   (interactive)
 164   (picture-set-motion 1 0))
 165
 166 (defun picture-movement-nw (&optional arg)
 167   "Move up and left after self-inserting character in Picture mode.
 168 With prefix argument, move up and two-column left."
 169   (interactive "P")
 170   (picture-set-motion -1 (if arg -2 -1)))
 171
 172 (defun picture-movement-ne (&optional arg)
 173   "Move up and right after self-inserting character in Picture mode.
 174 With prefix argument, move up and two-column right."
 175   (interactive "P")
 176   (picture-set-motion -1 (if arg 2 1)))
 177
 178 (defun picture-movement-sw (&optional arg)
 179   "Move down and left after self-inserting character in Picture mode.
 180 With prefix argument, move down and two-column left."
 181   (interactive "P")
 182   (picture-set-motion 1 (if arg -2 -1)))
 183
 184 (defun picture-movement-se (&optional arg)
 185   "Move down and right after self-inserting character in Picture mode.
 186 With prefix argument, move down and two-column right."
 187   (interactive "P")
 188   (picture-set-motion 1 (if arg 2 1)))
 189
 190 (defun picture-set-motion (vert horiz)
 191   "Set VERTICAL and HORIZONTAL increments for movement in Picture mode.
 192 The mode line is updated to reflect the current direction."
 193   (setq picture-vertical-step vert
 194         picture-horizontal-step horiz)
 195   (setq mode-name
 196         (format "Picture:%s"
 197                 (nth (+ 2 (% horiz 3) (* 5 (1+ (% vert 2))))
 198                      '(wnw nw up ne ene Left left none right Right
 199                            wsw sw down se ese))))
 200   (force-mode-line-update)
 201   (message ""))
 202
 203 (defun picture-move ()
 204   "Move in direction of `picture-vertical-step' and `picture-horizontal-step'."
 205   (if (/= picture-vertical-step 0)
 206       (picture-move-down picture-vertical-step))
 207   (if (/= picture-horizontal-step 0)
 208       (picture-forward-column picture-horizontal-step)))
 209
 210 (defun picture-motion (arg)
 211   "Move point in direction of current picture motion in Picture mode.
 212 With ARG do it that many times.  Useful for delineating rectangles in
 213 conjunction with diagonal picture motion.
 214 Do \\[command-apropos]  picture-movement  to see commands which control motion."
 215   (interactive "p")
 216   (picture-move-down (* arg picture-vertical-step))
 217   (picture-forward-column (* arg picture-horizontal-step)))
 218
 219 (defun picture-motion-reverse (arg)
 220   "Move point in direction opposite of current picture motion in Picture mode.
 221 With ARG do it that many times.  Useful for delineating rectangles in
 222 conjunction with diagonal picture motion.
 223 Do \\[command-apropos] `picture-movement' to see commands which control motion."
 224   (interactive "p")
 225   (picture-motion (- arg)))
 226
 227 \f
 228 ;; Picture insertion and deletion.
 229
 230 (defun picture-insert (ch arg)
 231   (let* ((width (char-width ch))
 232          ;; We must be sure that the succeeding insertion won't delete
 233          ;; the just inserted character.
 234          (picture-horizontal-step
 235           (if (and (= picture-vertical-step 0)
 236                    (> width 1)
 237                    (< (abs picture-horizontal-step) 2))
 238               (* picture-horizontal-step 2)
 239             picture-horizontal-step)))
 240     (while (> arg 0)
 241       (setq arg (1- arg))
 242       (if (/= picture-desired-column (current-column))
 243           (move-to-column-force picture-desired-column))
 244       (let ((col (+ picture-desired-column width)))
 245         (or (eolp)
 246             (let ((pos (point)))
 247               (move-to-column-force col)
 248               (delete-region pos (point)))))
 249       (insert ch)
 250       (forward-char -1)
 251       (picture-move))))
 252
 253 (defun picture-self-insert (arg)
 254   "Insert this character in place of character previously at the cursor.
 255 The cursor then moves in the direction you previously specified
 256 with the commands `picture-movement-right', `picture-movement-up', etc.
 257 Do \\[command-apropos] `picture-movement' to see those commands."
 258   (interactive "p")
 259   (picture-update-desired-column (not (eq this-command last-command)))
 260   (picture-insert last-command-event arg)) ; Always a character in this case.
 261
 262 (defun picture-clear-column (arg)
 263   "Clear out ARG columns after point without moving."
 264   (interactive "p")
 265   (let* ((original-col (current-column))
 266          (target-col (max 0 (+ original-col arg)))
 267          pos)
 268     (move-to-column-force target-col)
 269     (setq pos (point))
 270     (move-to-column original-col)
 271     (delete-region pos (point))
 272     (save-excursion
 273      (indent-to (max target-col original-col))))
 274   (setq picture-desired-column (current-column)))
 275
 276 (defun picture-backward-clear-column (arg)
 277   "Clear out ARG columns before point, moving back over them."
 278   (interactive "p")
 279   (picture-clear-column (- arg)))
 280
 281 (defun picture-clear-line (arg)
 282   "Clear out rest of line; if at end of line, advance to next line.
 283 Cleared-out line text goes into the kill ring, as do newlines that are
 284 advanced over.  With argument, clear out (and save in kill ring) that
 285 many lines."
 286   (interactive "P")
 287   (if arg
 288       (progn
 289        (setq arg (prefix-numeric-value arg))
 290        (kill-line arg)
 291        (newline (if (> arg 0) arg (- arg))))
 292     (if (looking-at "[ \t]*$")
 293         (kill-ring-save (point) (progn (forward-line 1) (point)))
 294       (kill-region (point) (progn (end-of-line) (point))))))
 295
 296 (defun picture-newline (arg)
 297   "Move to the beginning of the following line.
 298 With argument, moves that many lines (up, if negative argument);
 299 always moves to the beginning of a line."
 300   (interactive "p")
 301   (if (< arg 0)
 302       (forward-line arg)
 303     (while (> arg 0)
 304       (end-of-line)
 305       (if (eobp) (newline) (forward-char 1))
 306       (setq arg (1- arg)))))
 307
 308 (defun picture-open-line (arg)
 309   "Insert an empty line after the current line.
 310 With positive argument insert that many lines."
 311   (interactive "p")
 312   (save-excursion
 313    (end-of-line)
 314    (open-line arg)))
 315
 316 (defun picture-duplicate-line ()
 317   "Insert a duplicate of the current line, below it."
 318   (interactive)
 319   (save-excursion
 320    (let ((contents
 321           (buffer-substring
 322            (progn (beginning-of-line) (point))
 323            (progn (picture-newline 1) (point)))))
 324      (forward-line -1)
 325      (insert contents))))
 326
 327 ;; Like replace-match, but overwrites.
 328 (defun picture-replace-match (newtext fixedcase literal)
 329   (let (ocolumn change pos)
 330     (goto-char (setq pos (match-end 0)))
 331     (setq ocolumn (current-column))
 332     ;; Make the replacement and undo it, to see how it changes the length.
 333     (let ((buffer-undo-list nil)
 334           list1)
 335       (replace-match newtext fixedcase literal)
 336       (setq change (- (current-column) ocolumn))
 337       (setq list1 buffer-undo-list)
 338       (while list1
 339         (setq list1 (primitive-undo 1 list1))))
 340     (goto-char pos)
 341     (if (> change 0)
 342         (delete-region (point)
 343                        (progn
 344                          (move-to-column (+ change (current-column)) t)
 345                          (point))))
 346     (replace-match newtext fixedcase literal)
 347     (if (< change 0)
 348         (insert-char ?\ (- change)))))
 349 \f
 350 ;; Picture Tabs
 351
 352 (defcustom picture-tab-chars "!-~"
 353   "*A character set which controls behavior of commands.
 354 \\[picture-set-tab-stops] and \\[picture-tab-search].  It is NOT a
 355 regular expression, any regexp special characters will be quoted.
 356 It defines a set of \"interesting characters\" to look for when setting
 357 \(or searching for) tab stops, initially \"!-~\" (all printing characters).
 358 For example, suppose that you are editing a table which is formatted thus:
 359 | foo           | bar + baz | 23  *
 360 | bubbles       | and + etc | 97  *
 361 and that `picture-tab-chars' is \"|+*\".  Then invoking
 362 \\[picture-set-tab-stops] on either of the previous lines would result
 363 in the following tab stops
 364                 :     :     :     :
 365 Another example - \"A-Za-z0-9\" would produce the tab stops
 366   :               :     :     :
 367
 368 Note that if you want the character `-' to be in the set, it must be
 369 included in a range or else appear in a context where it cannot be
 370 taken for indicating a range (e.g. \"-A-Z\" declares the set to be the
 371 letters `A' through `Z' and the character `-').  If you want the
 372 character `\\' in the set it must be preceded by itself: \"\\\\\".
 373
 374 The command \\[picture-tab-search] is defined to move beneath (or to) a
 375 character belonging to this set independent of the tab stops list."
 376   :type 'string
 377   :group 'picture)
 378
 379 (defun picture-set-tab-stops (&optional arg)
 380   "Set value of `tab-stop-list' according to context of this line.
 381 This controls the behavior of \\[picture-tab].  A tab stop is set at
 382 every column occupied by an \"interesting character\" that is preceded
 383 by whitespace.  Interesting characters are defined by the variable
 384 `picture-tab-chars', see its documentation for an example of usage.
 385 With ARG, just (re)set `tab-stop-list' to its default value.  The tab
 386 stops computed are displayed in the minibuffer with `:' at each stop."
 387   (interactive "P")
 388   (save-excursion
 389     (let (tabs)
 390       (if arg
 391           (setq tabs (default-value 'tab-stop-list))
 392         (let ((regexp (concat "[ \t]+[" (regexp-quote picture-tab-chars) "]")))
 393           (beginning-of-line)
 394           (let ((bol (point)))
 395             (end-of-line)
 396             (while (re-search-backward regexp bol t)
 397               (skip-chars-forward " \t")
 398               (setq tabs (cons (current-column) tabs)))
 399             (if (null tabs)
 400                 (error "No characters in set %s on this line"
 401                        (regexp-quote picture-tab-chars))))))
 402       (setq tab-stop-list tabs)
 403       (let ((blurb (make-string (1+ (nth (1- (length tabs)) tabs)) ?\ )))
 404         (while tabs
 405           (aset blurb (car tabs) ?:)
 406           (setq tabs (cdr tabs)))
 407         (message blurb)))))
 408
 409 (defun picture-tab-search (&optional arg)
 410   "Move to column beneath next interesting char in previous line.
 411 With ARG move to column occupied by next interesting character in this
 412 line.  The character must be preceded by whitespace.
 413 \"interesting characters\" are defined by variable `picture-tab-chars'.
 414 If no such character is found, move to beginning of line."
 415   (interactive "P")
 416   (let ((target (current-column)))
 417     (save-excursion
 418       (if (and (not arg)
 419                (progn
 420                  (beginning-of-line)
 421                  (skip-chars-backward
 422                   (concat "^" (regexp-quote picture-tab-chars))
 423                   (point-min))
 424                  (not (bobp))))
 425           (move-to-column target))
 426       (if (re-search-forward
 427            (concat "[ \t]+[" (regexp-quote picture-tab-chars) "]")
 428            (save-excursion (end-of-line) (point))
 429            'move)
 430           (setq target (1- (current-column)))
 431         (setq target nil)))
 432     (if target
 433         (move-to-column target t)
 434       (beginning-of-line))))
 435
 436 (defun picture-tab (&optional arg)
 437   "Tab transparently (just move point) to next tab stop.
 438 With prefix arg, overwrite the traversed text with spaces.  The tab stop
 439 list can be changed by \\[picture-set-tab-stops] and \\[edit-tab-stops].
 440 See also documentation for variable `picture-tab-chars'."
 441   (interactive "P")
 442   (let* ((opoint (point)))
 443     (move-to-tab-stop)
 444     (if arg
 445         (let (indent-tabs-mode
 446               (column (current-column)))
 447           (delete-region opoint (point))
 448           (indent-to column)))))
 449 \f
 450 ;; Picture Rectangles
 451
 452 (defvar picture-killed-rectangle nil
 453   "Rectangle killed or copied by \\[picture-clear-rectangle] in Picture mode.
 454 The contents can be retrieved by \\[picture-yank-rectangle]")
 455
 456 (defun picture-clear-rectangle (start end &optional killp)
 457   "Clear and save rectangle delineated by point and mark.
 458 The rectangle is saved for yanking by \\[picture-yank-rectangle] and replaced
 459 with whitespace.  The previously saved rectangle, if any, is lost.  With
 460 prefix argument, the rectangle is actually killed, shifting remaining text."
 461   (interactive "r\nP")
 462   (setq picture-killed-rectangle (picture-snarf-rectangle start end killp)))
 463
 464 (defun picture-clear-rectangle-to-register (start end register &optional killp)
 465   "Clear rectangle delineated by point and mark into REGISTER.
 466 The rectangle is saved in REGISTER and replaced with whitespace.  With
 467 prefix argument, the rectangle is actually killed, shifting remaining text."
 468   (interactive "r\ncRectangle to register: \nP")
 469   (set-register register (picture-snarf-rectangle start end killp)))
 470
 471 (defun picture-snarf-rectangle (start end &optional killp)
 472   (let ((column (current-column))
 473         (indent-tabs-mode nil))
 474     (prog1 (save-excursion
 475              (if killp
 476                  (delete-extract-rectangle start end)
 477                (prog1 (extract-rectangle start end)
 478                       (clear-rectangle start end))))
 479            (move-to-column column t))))
 480
 481 (defun picture-yank-rectangle (&optional insertp)
 482   "Overlay rectangle saved by \\[picture-clear-rectangle]
 483 The rectangle is positioned with upper left corner at point, overwriting
 484 existing text.  With prefix argument, the rectangle is inserted instead,
 485 shifting existing text.  Leaves mark at one corner of rectangle and
 486 point at the other (diagonally opposed) corner."
 487   (interactive "P")
 488   (if (not (consp picture-killed-rectangle))
 489       (error "No rectangle saved")
 490     (picture-insert-rectangle picture-killed-rectangle insertp)))
 491
 492 (defun picture-yank-at-click (click arg)
 493   "Insert the last killed rectangle at the position clicked on.
 494 Also move point to one end of the text thus inserted (normally the end).
 495 Prefix arguments are interpreted as with \\[yank].
 496 If `mouse-yank-at-point' is non-nil, insert at point
 497 regardless of where you click."
 498   (interactive "e\nP")
 499   (or mouse-yank-at-point (mouse-set-point click))
 500   (picture-yank-rectangle arg))
 501
 502 (defun picture-yank-rectangle-from-register (register &optional insertp)
 503   "Overlay rectangle saved in REGISTER.
 504 The rectangle is positioned with upper left corner at point, overwriting
 505 existing text.  With prefix argument, the rectangle is
 506 inserted instead, shifting existing text.  Leaves mark at one corner
 507 of rectangle and point at the other (diagonally opposed) corner."
 508   (interactive "cRectangle from register: \nP")
 509   (let ((rectangle (get-register register)))
 510     (if (not (consp rectangle))
 511         (error "Register %c does not contain a rectangle" register)
 512       (picture-insert-rectangle rectangle insertp))))
 513
 514 (defun picture-insert-rectangle (rectangle &optional insertp)
 515   "Overlay RECTANGLE with upper left corner at point.
 516 Optional argument INSERTP, if non-nil causes RECTANGLE to be inserted.
 517 Leaves the region surrounding the rectangle."
 518   (let ((indent-tabs-mode nil))
 519     (if (not insertp)
 520         (save-excursion
 521           (delete-rectangle (point)
 522                             (progn
 523                               (picture-forward-column (length (car rectangle)))
 524                               (picture-move-down (1- (length rectangle)))
 525                               (point)))))
 526     (push-mark)
 527     (insert-rectangle rectangle)))
 528
 529 (defun picture-current-line ()
 530   "Return the vertical position of point.  Top line is 1."
 531   (+ (count-lines (point-min) (point))
 532      (if (= (current-column) 0) 1 0)))
 533
 534 (defun picture-draw-rectangle (start end)
 535   "Draw a rectangle around region."
 536   (interactive "*r")                    ; start will be less than end
 537   (let* ((sl     (picture-current-line))
 538          (sc     (current-column))
 539          (pvs    picture-vertical-step)
 540          (phs    picture-horizontal-step)
 541          (c1     (progn (goto-char start) (current-column)))
 542          (r1     (picture-current-line))
 543          (c2     (progn (goto-char end) (current-column)))
 544          (r2     (picture-current-line))
 545          (right  (max c1 c2))
 546          (left   (min c1 c2))
 547          (top    (min r1 r2))
 548          (bottom (max r1 r2)))
 549     (goto-line top)
 550     (move-to-column-force left)
 551     (picture-update-desired-column t)
 552
 553     (picture-movement-right)
 554     (picture-insert picture-rectangle-ctl 1)
 555     (picture-insert picture-rectangle-h (- right picture-desired-column))
 556
 557     (picture-movement-down)
 558     (picture-insert picture-rectangle-ctr 1)
 559     (picture-insert picture-rectangle-v (- bottom (picture-current-line)))
 560
 561     (picture-movement-left)
 562     (picture-insert picture-rectangle-cbr 1)
 563     (picture-insert picture-rectangle-h (- picture-desired-column left))
 564
 565     (picture-movement-up)
 566     (picture-insert picture-rectangle-cbl 1)
 567     (picture-insert picture-rectangle-v (- (picture-current-line) top))
 568
 569     (picture-set-motion pvs phs)
 570     (goto-line sl)
 571     (move-to-column sc t)))
 572
 573 \f
 574 ;; Picture Keymap, entry and exit points.
 575
 576 (defconst picture-mode-map nil)
 577
 578 (defun picture-substitute (oldfun newfun)
 579   (substitute-key-definition oldfun newfun picture-mode-map global-map))
 580
 581 (if (not picture-mode-map)
 582     (progn
 583       (setq picture-mode-map (make-keymap))
 584       (picture-substitute 'self-insert-command 'picture-self-insert)
 585       (picture-substitute 'completion-separator-self-insert-command
 586                           'picture-self-insert)
 587       (picture-substitute 'completion-separator-self-insert-autofilling
 588                           'picture-self-insert)
 589       (picture-substitute 'forward-char 'picture-forward-column)
 590       (picture-substitute 'backward-char 'picture-backward-column)
 591       (picture-substitute 'delete-char 'picture-clear-column)
 592       ;; There are two possibilities for what is normally on DEL.
 593       (picture-substitute 'backward-delete-char-untabify 'picture-backward-clear-column)
 594       (picture-substitute 'delete-backward-char 'picture-backward-clear-column)
 595       (picture-substitute 'kill-line 'picture-clear-line)
 596       (picture-substitute 'open-line 'picture-open-line)
 597       (picture-substitute 'newline 'picture-newline)
 598       (picture-substitute 'newline-and-indent 'picture-duplicate-line)
 599       (picture-substitute 'next-line 'picture-move-down)
 600       (picture-substitute 'previous-line 'picture-move-up)
 601       (picture-substitute 'beginning-of-line 'picture-beginning-of-line)
 602       (picture-substitute 'end-of-line 'picture-end-of-line)
 603
 604       (define-key picture-mode-map "\C-c\C-d" 'delete-char)
 605       (define-key picture-mode-map "\e\t" 'picture-toggle-tab-state)
 606       (define-key picture-mode-map "\t" 'picture-tab)
 607       (define-key picture-mode-map "\e\t" 'picture-tab-search)
 608       (define-key picture-mode-map "\C-c\t" 'picture-set-tab-stops)
 609       (define-key picture-mode-map "\C-c\C-k" 'picture-clear-rectangle)
 610       (define-key picture-mode-map "\C-c\C-w" 'picture-clear-rectangle-to-register)
 611       (define-key picture-mode-map "\C-c\C-y" 'picture-yank-rectangle)
 612       (define-key picture-mode-map "\C-c\C-x" 'picture-yank-rectangle-from-register)
 613       (define-key picture-mode-map "\C-c\C-r" 'picture-draw-rectangle)
 614       (define-key picture-mode-map "\C-c\C-c" 'picture-mode-exit)
 615       (define-key picture-mode-map "\C-c\C-f" 'picture-motion)
 616       (define-key picture-mode-map "\C-c\C-b" 'picture-motion-reverse)
 617       (define-key picture-mode-map "\C-c<" 'picture-movement-left)
 618       (define-key picture-mode-map "\C-c>" 'picture-movement-right)
 619       (define-key picture-mode-map "\C-c^" 'picture-movement-up)
 620       (define-key picture-mode-map "\C-c." 'picture-movement-down)
 621       (define-key picture-mode-map "\C-c`" 'picture-movement-nw)
 622       (define-key picture-mode-map "\C-c'" 'picture-movement-ne)
 623       (define-key picture-mode-map "\C-c/" 'picture-movement-sw)
 624       (define-key picture-mode-map "\C-c\\" 'picture-movement-se)))
 625
 626 (defcustom picture-mode-hook nil
 627   "If non-nil, its value is called on entry to Picture mode.
 628 Picture mode is invoked by the command \\[picture-mode]."
 629   :type 'hook
 630   :group 'picture)
 631
 632 (defvar picture-mode-old-local-map)
 633 (defvar picture-mode-old-mode-name)
 634 (defvar picture-mode-old-major-mode)
 635 (defvar picture-mode-old-truncate-lines)
 636
 637 ;;;###autoload
 638 (defun picture-mode ()
 639   "Switch to Picture mode, in which a quarter-plane screen model is used.
 640 Printing characters replace instead of inserting themselves with motion
 641 afterwards settable by these commands:
 642   C-c <   Move left after insertion.
 643   C-c >   Move right after insertion.
 644   C-c ^   Move up after insertion.
 645   C-c .   Move down after insertion.
 646   C-c `   Move northwest (nw) after insertion.
 647   C-c '   Move northeast (ne) after insertion.
 648   C-c /   Move southwest (sw) after insertion.
 649   C-c \\   Move southeast (se) after insertion.
 650   C-u C-c `  Move westnorthwest (wnw) after insertion.
 651   C-u C-c '  Move eastnortheast (ene) after insertion.
 652   C-u C-c /  Move westsouthwest (wsw) after insertion.
 653   C-u C-c \\  Move eastsoutheast (ese) after insertion.
 654 The current direction is displayed in the mode line.  The initial
 655 direction is right.  Whitespace is inserted and tabs are changed to
 656 spaces when required by movement.  You can move around in the buffer
 657 with these commands:
 658   \\[picture-move-down]   Move vertically to SAME column in previous line.
 659   \\[picture-move-up]     Move vertically to SAME column in next line.
 660   \\[picture-end-of-line]         Move to column following last non-whitespace character.
 661   \\[picture-forward-column]      Move right inserting spaces if required.
 662   \\[picture-backward-column]     Move left changing tabs to spaces if required.
 663   C-c C-f Move in direction of current picture motion.
 664   C-c C-b Move in opposite direction of current picture motion.
 665   Return  Move to beginning of next line.
 666 You can edit tabular text with these commands:
 667   M-Tab   Move to column beneath (or at) next interesting character.
 668             `Indents' relative to a previous line.
 669   Tab     Move to next stop in tab stop list.
 670   C-c Tab Set tab stops according to context of this line.
 671             With ARG resets tab stops to default (global) value.
 672             See also documentation of variable  picture-tab-chars
 673             which defines \"interesting character\".  You can manually
 674             change the tab stop list with command \\[edit-tab-stops].
 675 You can manipulate text with these commands:
 676   C-d     Clear (replace) ARG columns after point without moving.
 677   C-c C-d Delete char at point - the command normally assigned to C-d.
 678   \\[picture-backward-clear-column]  Clear (replace) ARG columns before point, moving back over them.
 679   \\[picture-clear-line]          Clear ARG lines, advancing over them.  The cleared
 680             text is saved in the kill ring.
 681   \\[picture-open-line]   Open blank line(s) beneath current line.
 682 You can manipulate rectangles with these commands:
 683   C-c C-k Clear (or kill) a rectangle and save it.
 684   C-c C-w Like C-c C-k except rectangle is saved in named register.
 685   C-c C-y Overlay (or insert) currently saved rectangle at point.
 686   C-c C-x Like C-c C-y except rectangle is taken from named register.
 687   C-c C-r Draw a rectangular box around mark and point.
 688   \\[copy-rectangle-to-register]   Copies a rectangle to a register.
 689   \\[advertised-undo]   Can undo effects of rectangle overlay commands
 690             commands if invoked soon enough.
 691 You can return to the previous mode with:
 692   C-c C-c Which also strips trailing whitespace from every line.
 693             Stripping is suppressed by supplying an argument.
 694
 695 Entry to this mode calls the value of `picture-mode-hook' if non-nil.
 696
 697 Note that Picture mode commands will work outside of Picture mode, but
 698 they are not defaultly assigned to keys."
 699   (interactive)
 700   (if (eq major-mode 'picture-mode)
 701       (error "You are already editing a picture")
 702     (set (make-local-variable 'picture-mode-old-local-map) (current-local-map))
 703     (use-local-map picture-mode-map)
 704     (set (make-local-variable 'picture-mode-old-mode-name) mode-name)
 705     (set (make-local-variable 'picture-mode-old-major-mode) major-mode)
 706     (setq major-mode 'picture-mode)
 707     (set (make-local-variable 'picture-killed-rectangle) nil)
 708     (set (make-local-variable 'tab-stop-list) (default-value 'tab-stop-list))
 709     (set (make-local-variable 'picture-tab-chars)
 710          (default-value 'picture-tab-chars))
 711     (make-local-variable 'picture-vertical-step)
 712     (make-local-variable 'picture-horizontal-step)
 713     (set (make-local-variable 'picture-mode-old-truncate-lines) truncate-lines)
 714     (setq truncate-lines t)
 715     (picture-set-motion 0 1)
 716
 717     ;; edit-picture-hook is what we used to run, picture-mode-hook is in doc.
 718     (run-hooks 'edit-picture-hook 'picture-mode-hook)
 719     (message "Type %s in this buffer to return it to %s mode."
 720              (substitute-command-keys "\\[picture-mode-exit]")
 721              picture-mode-old-mode-name)))
 722
 723 ;;;###autoload
 724 (defalias 'edit-picture 'picture-mode)
 725
 726 (defun picture-mode-exit (&optional nostrip)
 727   "Undo picture-mode and return to previous major mode.
 728 With no argument strips whitespace from end of every line in Picture buffer
 729   otherwise just return to previous mode."
 730   (interactive "P")
 731   (if (not (eq major-mode 'picture-mode))
 732       (error "You aren't editing a Picture")
 733     (if (not nostrip) (delete-trailing-whitespace))
 734     (setq mode-name picture-mode-old-mode-name)
 735     (use-local-map picture-mode-old-local-map)
 736     (setq major-mode picture-mode-old-major-mode)
 737     (kill-local-variable 'tab-stop-list)
 738     (setq truncate-lines picture-mode-old-truncate-lines)
 739     (force-mode-line-update)))
 740
 741 (provide 'picture)
 742
 743 ;;; picture.el ends here