lisp/ruler-mode.el

   1 ;;; ruler-mode.el --- display a ruler in the header line
   2
   3 ;; Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc.
   4
   5 ;; Author: David Ponce <david@dponce.com>
   6 ;; Maintainer: David Ponce <david@dponce.com>
   7 ;; Created: 24 Mar 2001
   8 ;; Version: 1.6
   9 ;; Keywords: convenience
  10
  11 ;; This file is part of GNU Emacs.
  12
  13 ;; This program is free software; you can redistribute it and/or
  14 ;; modify it under the terms of the GNU General Public License as
  15 ;; published by the Free Software Foundation; either version 2, or (at
  16 ;; your option) any later version.
  17
  18 ;; This program is distributed in the hope that it will be useful, but
  19 ;; WITHOUT ANY WARRANTY; without even the implied warranty of
  20 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  21 ;; General Public License for more details.
  22
  23 ;; You should have received a copy of the GNU General Public License
  24 ;; along with this program; see the file COPYING.  If not, write to
  25 ;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  26 ;; Boston, MA 02111-1307, USA.
  27
  28 ;;; Commentary:
  29
  30 ;; This library provides a minor mode to display a ruler in the header
  31 ;; line.  It works only on Emacs 21.
  32 ;;
  33 ;; You can use the mouse to change the `fill-column' `comment-column',
  34 ;; `goal-column', `window-margins' and `tab-stop-list' settings:
  35 ;;
  36 ;; [header-line (shift down-mouse-1)] set left margin end to the ruler
  37 ;; graduation where the mouse pointer is on.
  38 ;;
  39 ;; [header-line (shift down-mouse-3)] set right margin beginning to
  40 ;; the ruler graduation where the mouse pointer is on.
  41 ;;
  42 ;; [header-line down-mouse-2] Drag the `fill-column', `comment-column'
  43 ;; or `goal-column' to a ruler graduation.
  44 ;;
  45 ;; [header-line (control down-mouse-1)] add a tab stop to the ruler
  46 ;; graduation where the mouse pointer is on.
  47 ;;
  48 ;; [header-line (control down-mouse-3)] remove the tab stop at the
  49 ;; ruler graduation where the mouse pointer is on.
  50 ;;
  51 ;; [header-line (control down-mouse-2)] or M-x
  52 ;; `ruler-mode-toggle-show-tab-stops' toggle showing and visually
  53 ;; editing `tab-stop-list' setting.  The `ruler-mode-show-tab-stops'
  54 ;; option controls if the ruler shows tab stops by default.
  55 ;;
  56 ;; In the ruler the character `ruler-mode-current-column-char' shows
  57 ;; the `current-column' location, `ruler-mode-fill-column-char' shows
  58 ;; the `fill-column' location, `ruler-mode-comment-column-char' shows
  59 ;; the `comment-column' location, `ruler-mode-goal-column-char' shows
  60 ;; the `goal-column' and `ruler-mode-tab-stop-char' shows tab stop
  61 ;; locations.  Graduations in `window-margins' and `window-fringes'
  62 ;; areas are shown with a different foreground color.
  63 ;;
  64 ;; It is also possible to customize the following characters:
  65 ;;
  66 ;; - `ruler-mode-basic-graduation-char' character used for basic
  67 ;;   graduations ('.' by default).
  68 ;; - `ruler-mode-inter-graduation-char' character used for
  69 ;;   intermediate graduations ('!' by default).
  70 ;;
  71 ;; The following faces are customizable:
  72 ;;
  73 ;; - `ruler-mode-default-face' the ruler default face.
  74 ;; - `ruler-mode-fill-column-face' the face used to highlight the
  75 ;;   `fill-column' character.
  76 ;; - `ruler-mode-comment-column-face' the face used to highlight the
  77 ;;   `comment-column' character.
  78 ;; - `ruler-mode-goal-column-face' the face used to highlight the
  79 ;;   `goal-column' character.
  80 ;; - `ruler-mode-current-column-face' the face used to highlight the
  81 ;;   `current-column' character.
  82 ;; - `ruler-mode-tab-stop-face' the face used to highlight tab stop
  83 ;;   characters.
  84 ;; - `ruler-mode-margins-face' the face used to highlight graduations
  85 ;;   in the `window-margins' areas.
  86 ;; - `ruler-mode-fringes-face' the face used to highlight graduations
  87 ;;   in the `window-fringes' areas.
  88 ;; - `ruler-mode-column-number-face' the face used to highlight the
  89 ;;   numbered graduations.
  90 ;;
  91 ;; `ruler-mode-default-face' inherits from the built-in `default' face.
  92 ;; All `ruler-mode' faces inherit from `ruler-mode-default-face'.
  93 ;;
  94 ;; WARNING: To keep ruler graduations aligned on text columns it is
  95 ;; important to use the same font family and size for ruler and text
  96 ;; areas.
  97
  98 ;; Installation
  99 ;;
 100 ;; To automatically display the ruler in specific major modes use:
 101 ;;
 102 ;;    (add-hook '<major-mode>-hook 'ruler-mode)
 103 ;;
 104
 105 ;;; History:
 106 ;;
 107 \f
 108 ;;; Code:
 109 (eval-when-compile
 110   (require 'wid-edit))
 111
 112 (defgroup ruler-mode nil
 113   "Display a ruler in the header line."
 114   :version "21.4"
 115   :group 'convenience)
 116
 117 (defcustom ruler-mode-show-tab-stops nil
 118   "*If non-nil the ruler shows tab stop positions.
 119 Also allowing to visually change `tab-stop-list' setting using
 120 <C-down-mouse-1> and <C-down-mouse-3> on the ruler to respectively add
 121 or remove a tab stop.  \\[ruler-mode-toggle-show-tab-stops] or
 122 <C-down-mouse-2> on the ruler toggles showing/editing of tab stops."
 123   :group 'ruler-mode
 124   :type 'boolean)
 125
 126 ;; IMPORTANT: This function must be defined before the following
 127 ;; defcustoms because it is used in their :validate clause.
 128 (defun ruler-mode-character-validate (widget)
 129   "Ensure WIDGET value is a valid character value."
 130   (save-excursion
 131     (let ((value (widget-value widget)))
 132       (if (char-valid-p value)
 133           nil
 134         (widget-put widget :error
 135                     (format "Invalid character value: %S" value))
 136         widget))))
 137
 138 (defcustom ruler-mode-fill-column-char (if (char-displayable-p ?¶)
 139                                            ?\¶
 140                                          ?\|)
 141   "*Character used at the `fill-column' location."
 142   :group 'ruler-mode
 143   :type '(choice
 144           (character :tag "Character")
 145           (integer :tag "Integer char value"
 146                    :validate ruler-mode-character-validate)))
 147
 148 (defcustom ruler-mode-comment-column-char ?\#
 149   "*Character used at the `comment-column' location."
 150   :group 'ruler-mode
 151   :type '(choice
 152           (character :tag "Character")
 153           (integer :tag "Integer char value"
 154                    :validate ruler-mode-character-validate)))
 155
 156 (defcustom ruler-mode-goal-column-char ?G
 157   "*Character used at the `goal-column' location."
 158   :group 'ruler-mode
 159   :type '(choice
 160           (character :tag "Character")
 161           (integer :tag "Integer char value"
 162                    :validate ruler-mode-character-validate)))
 163
 164 (defcustom ruler-mode-current-column-char (if (char-displayable-p ?¦)
 165                                               ?\¦
 166                                             ?\@)
 167   "*Character used at the `current-column' location."
 168   :group 'ruler-mode
 169   :type '(choice
 170           (character :tag "Character")
 171           (integer :tag "Integer char value"
 172                    :validate ruler-mode-character-validate)))
 173
 174 (defcustom ruler-mode-tab-stop-char ?\T
 175   "*Character used at `tab-stop-list' locations."
 176   :group 'ruler-mode
 177   :type '(choice
 178           (character :tag "Character")
 179           (integer :tag "Integer char value"
 180                    :validate ruler-mode-character-validate)))
 181
 182 (defcustom ruler-mode-basic-graduation-char ?\.
 183   "*Character used for basic graduations."
 184   :group 'ruler-mode
 185   :type '(choice
 186           (character :tag "Character")
 187           (integer :tag "Integer char value"
 188                    :validate ruler-mode-character-validate)))
 189
 190 (defcustom ruler-mode-inter-graduation-char ?\!
 191   "*Character used for intermediate graduations."
 192   :group 'ruler-mode
 193   :type '(choice
 194           (character :tag "Character")
 195           (integer :tag "Integer char value"
 196                    :validate ruler-mode-character-validate)))
 197
 198 (defcustom ruler-mode-set-goal-column-ding-flag t
 199   "*Non-nil means do `ding' when `goal-column' is set."
 200   :group 'ruler-mode
 201   :type 'boolean)
 202 \f
 203 (defface ruler-mode-default-face
 204   '((((type tty))
 205      (:inherit default
 206                :background "grey64"
 207                :foreground "grey50"
 208                ))
 209     (t
 210      (:inherit default
 211                :background "grey76"
 212                :foreground "grey64"
 213                :box (:color "grey76"
 214                             :line-width 1
 215                             :style released-button)
 216                )))
 217   "Default face used by the ruler."
 218   :group 'ruler-mode)
 219
 220 (defface ruler-mode-pad-face
 221   '((((type tty))
 222      (:inherit ruler-mode-default-face
 223                :background "grey50"
 224                ))
 225     (t
 226      (:inherit ruler-mode-default-face
 227                :background "grey64"
 228                )))
 229   "Face used to pad inactive ruler areas."
 230   :group 'ruler-mode)
 231
 232 (defface ruler-mode-margins-face
 233   '((t
 234      (:inherit ruler-mode-default-face
 235                :foreground "white"
 236                )))
 237   "Face used to highlight margin areas."
 238   :group 'ruler-mode)
 239
 240 (defface ruler-mode-fringes-face
 241   '((t
 242      (:inherit ruler-mode-default-face
 243                :foreground "green"
 244                )))
 245   "Face used to highlight fringes areas."
 246   :group 'ruler-mode)
 247
 248 (defface ruler-mode-column-number-face
 249   '((t
 250      (:inherit ruler-mode-default-face
 251                :foreground "black"
 252                )))
 253   "Face used to highlight number graduations."
 254   :group 'ruler-mode)
 255
 256 (defface ruler-mode-fill-column-face
 257   '((t
 258      (:inherit ruler-mode-default-face
 259                :foreground "red"
 260                )))
 261   "Face used to highlight the fill column character."
 262   :group 'ruler-mode)
 263
 264 (defface ruler-mode-comment-column-face
 265   '((t
 266      (:inherit ruler-mode-default-face
 267                :foreground "red"
 268                )))
 269   "Face used to highlight the comment column character."
 270   :group 'ruler-mode)
 271
 272 (defface ruler-mode-goal-column-face
 273   '((t
 274      (:inherit ruler-mode-default-face
 275                :foreground "red"
 276                )))
 277   "Face used to highlight the goal column character."
 278   :group 'ruler-mode)
 279
 280 (defface ruler-mode-tab-stop-face
 281   '((t
 282      (:inherit ruler-mode-default-face
 283                :foreground "steelblue"
 284                )))
 285   "Face used to highlight tab stop characters."
 286   :group 'ruler-mode)
 287
 288 (defface ruler-mode-current-column-face
 289   '((t
 290      (:inherit ruler-mode-default-face
 291                :weight bold
 292                :foreground "yellow"
 293                )))
 294   "Face used to highlight the `current-column' character."
 295   :group 'ruler-mode)
 296 \f
 297 (defmacro ruler-mode-left-fringe-cols ()
 298   "Return the width, measured in columns, of the left fringe area."
 299   '(ceiling (or (car (window-fringes)) 0)
 300             (frame-char-width)))
 301
 302 (defmacro ruler-mode-right-fringe-cols ()
 303   "Return the width, measured in columns, of the right fringe area."
 304   '(ceiling (or (nth 1 (window-fringes)) 0)
 305             (frame-char-width)))
 306
 307 (defun ruler-mode-left-scroll-bar-cols ()
 308   "Return the width, measured in columns, of the right vertical scrollbar."
 309   (let* ((wsb   (window-scroll-bars))
 310          (vtype (nth 2 wsb))
 311          (cols  (nth 1 wsb)))
 312     (if (or (eq vtype 'left)
 313             (and (eq vtype t)
 314                  (eq (frame-parameter nil 'vertical-scroll-bars) 'left)))
 315         (or cols
 316             (ceiling
 317              ;; nil means it's a non-toolkit scroll bar,
 318              ;; and its width in columns is 14 pixels rounded up.
 319              (or (frame-parameter nil 'scroll-bar-width) 14)
 320              ;; Always round up to multiple of columns.
 321              (frame-char-width)))
 322       0)))
 323
 324 (defun ruler-mode-right-scroll-bar-cols ()
 325   "Return the width, measured in columns, of the right vertical scrollbar."
 326   (let* ((wsb   (window-scroll-bars))
 327          (vtype (nth 2 wsb))
 328          (cols  (nth 1 wsb)))
 329     (if (or (eq vtype 'right)
 330             (and (eq vtype t)
 331                  (eq (frame-parameter nil 'vertical-scroll-bars) 'right)))
 332         (or cols
 333             (ceiling
 334              ;; nil means it's a non-toolkit scroll bar,
 335              ;; and its width in columns is 14 pixels rounded up.
 336              (or (frame-parameter nil 'scroll-bar-width) 14)
 337              ;; Always round up to multiple of columns.
 338              (frame-char-width)))
 339       0)))
 340
 341 (defsubst ruler-mode-full-window-width ()
 342   "Return the full width of the selected window."
 343   (let ((edges (window-edges)))
 344     (- (nth 2 edges) (nth 0 edges))))
 345
 346 (defsubst ruler-mode-window-col (n)
 347   "Return a column number relative to the selected window.
 348 N is a column number relative to selected frame."
 349   (- n
 350      (car (window-edges))
 351      (or (car (window-margins)) 0)
 352      (ruler-mode-left-fringe-cols)
 353      (ruler-mode-left-scroll-bar-cols)))
 354 \f
 355 (defun ruler-mode-mouse-set-left-margin (start-event)
 356   "Set left margin end to the graduation where the mouse pointer is on.
 357 START-EVENT is the mouse click event."
 358   (interactive "e")
 359   (let* ((start (event-start start-event))
 360          (end   (event-end   start-event))
 361          col w lm rm)
 362     (when (eq start end) ;; mouse click
 363       (save-selected-window
 364         (select-window (posn-window start))
 365         (setq col (- (car (posn-col-row start)) (car (window-edges))
 366                      (ruler-mode-left-scroll-bar-cols))
 367               w   (- (ruler-mode-full-window-width)
 368                      (ruler-mode-left-scroll-bar-cols)
 369                      (ruler-mode-right-scroll-bar-cols)))
 370         (when (and (>= col 0) (< col w))
 371           (setq lm (window-margins)
 372                 rm (or (cdr lm) 0)
 373                 lm (or (car lm) 0))
 374           (message "Left margin set to %d (was %d)" col lm)
 375           (set-window-margins nil col rm))))))
 376
 377 (defun ruler-mode-mouse-set-right-margin (start-event)
 378   "Set right margin beginning to the graduation where the mouse pointer is on.
 379 START-EVENT is the mouse click event."
 380   (interactive "e")
 381   (let* ((start (event-start start-event))
 382          (end   (event-end   start-event))
 383          col w lm rm)
 384     (when (eq start end) ;; mouse click
 385       (save-selected-window
 386         (select-window (posn-window start))
 387         (setq col (- (car (posn-col-row start)) (car (window-edges))
 388                      (ruler-mode-left-scroll-bar-cols))
 389               w   (- (ruler-mode-full-window-width)
 390                      (ruler-mode-left-scroll-bar-cols)
 391                      (ruler-mode-right-scroll-bar-cols)))
 392         (when (and (>= col 0) (< col w))
 393           (setq lm  (window-margins)
 394                 rm  (or (cdr lm) 0)
 395                 lm  (or (car lm) 0)
 396                 col (- w col 1))
 397           (message "Right margin set to %d (was %d)" col rm)
 398           (set-window-margins nil lm col))))))
 399
 400 (defvar ruler-mode-dragged-symbol nil
 401   "Column symbol dragged in the ruler.
 402 That is `fill-column', `comment-column', `goal-column', or nil when
 403 nothing is dragged.")
 404
 405 (defun ruler-mode-mouse-grab-any-column (start-event)
 406   "Drag a column symbol on the ruler.
 407 Start dragging on mouse down event START-EVENT, and update the column
 408 symbol value with the current value of the ruler graduation while
 409 dragging.  See also the variable `ruler-mode-dragged-symbol'."
 410   (interactive "e")
 411   (setq ruler-mode-dragged-symbol nil)
 412   (let* ((start (event-start start-event))
 413          col newc oldc)
 414     (save-selected-window
 415       (select-window (posn-window start))
 416       (setq col  (ruler-mode-window-col (car (posn-col-row start)))
 417             newc (+ col (window-hscroll)))
 418       (and
 419        (>= col 0) (< col (window-width))
 420        (cond
 421
 422         ;; Handle the fill column.
 423         ((eq newc fill-column)
 424          (setq oldc fill-column
 425                ruler-mode-dragged-symbol 'fill-column)
 426          t) ;; Start dragging
 427
 428         ;; Handle the comment column.
 429         ((eq newc comment-column)
 430          (setq oldc comment-column
 431                ruler-mode-dragged-symbol 'comment-column)
 432          t) ;; Start dragging
 433
 434         ;; Handle the goal column.
 435         ;; A. On mouse down on the goal column character on the ruler,
 436         ;;    update the `goal-column' value while dragging.
 437         ;; B. If `goal-column' is nil, set the goal column where the
 438         ;;    mouse is clicked.
 439         ;; C. On mouse click on the goal column character on the
 440         ;;    ruler, unset the goal column.
 441         ((eq newc goal-column)          ; A. Drag the goal column.
 442          (setq oldc goal-column
 443                ruler-mode-dragged-symbol 'goal-column)
 444          t) ;; Start dragging
 445
 446         ((null goal-column)             ; B. Set the goal column.
 447          (setq oldc goal-column
 448                goal-column newc)
 449          ;; mouse-2 coming AFTER drag-mouse-2 invokes `ding'.  This
 450          ;; `ding' flushes the next messages about setting goal
 451          ;; column.  So here I force fetch the event(mouse-2) and
 452          ;; throw away.
 453          (read-event)
 454          ;; Ding BEFORE `message' is OK.
 455          (when ruler-mode-set-goal-column-ding-flag
 456            (ding))
 457          (message "Goal column set to %d (click on %s again to unset it)"
 458                   newc
 459                   (propertize (char-to-string ruler-mode-goal-column-char)
 460                               'face 'ruler-mode-goal-column-face))
 461          nil) ;; Don't start dragging.
 462         )
 463        (if (eq 'click (ruler-mode-mouse-drag-any-column-iteration
 464                        (posn-window start)))
 465            (when (eq 'goal-column ruler-mode-dragged-symbol)
 466              ;; C. Unset the goal column.
 467              (set-goal-column t))
 468          ;; At end of dragging, report the updated column symbol.
 469          (message "%s is set to %d (was %d)"
 470                   ruler-mode-dragged-symbol
 471                   (symbol-value ruler-mode-dragged-symbol)
 472                   oldc))))))
 473
 474 (defun ruler-mode-mouse-drag-any-column-iteration (window)
 475   "Update the ruler while dragging the mouse.
 476 WINDOW is the window where occurred the last down-mouse event.
 477 Return the symbol `drag' if the mouse has been dragged, or `click' if
 478 the mouse has been clicked."
 479   (let ((drags 0)
 480         event)
 481     (track-mouse
 482       (while (mouse-movement-p (setq event (read-event)))
 483         (setq drags (1+ drags))
 484         (when (eq window (posn-window (event-end event)))
 485           (ruler-mode-mouse-drag-any-column event)
 486           (force-mode-line-update))))
 487     (if (and (zerop drags) (eq 'click (car (event-modifiers event))))
 488         'click
 489       'drag)))
 490
 491 (defun ruler-mode-mouse-drag-any-column (start-event)
 492   "Update the value of the symbol dragged on the ruler.
 493 Called on each mouse motion event START-EVENT."
 494   (let* ((start (event-start start-event))
 495          (end   (event-end   start-event))
 496          col newc)
 497     (save-selected-window
 498       (select-window (posn-window start))
 499       (setq col  (ruler-mode-window-col (car (posn-col-row end)))
 500             newc (+ col (window-hscroll)))
 501       (when (and (>= col 0) (< col (window-width)))
 502         (set ruler-mode-dragged-symbol newc)))))
 503 \f
 504 (defun ruler-mode-mouse-add-tab-stop (start-event)
 505   "Add a tab stop to the graduation where the mouse pointer is on.
 506 START-EVENT is the mouse click event."
 507   (interactive "e")
 508   (when ruler-mode-show-tab-stops
 509     (let* ((start (event-start start-event))
 510            (end   (event-end   start-event))
 511            col ts)
 512       (when (eq start end) ;; mouse click
 513         (save-selected-window
 514           (select-window (posn-window start))
 515           (setq col (ruler-mode-window-col (car (posn-col-row start)))
 516                 ts  (+ col (window-hscroll)))
 517           (and (>= col 0) (< col (window-width))
 518                (not (member ts tab-stop-list))
 519                (progn
 520                  (message "Tab stop set to %d" ts)
 521                  (setq tab-stop-list (sort (cons ts tab-stop-list)
 522                                            #'<)))))))))
 523
 524 (defun ruler-mode-mouse-del-tab-stop (start-event)
 525   "Delete tab stop at the graduation where the mouse pointer is on.
 526 START-EVENT is the mouse click event."
 527   (interactive "e")
 528   (when ruler-mode-show-tab-stops
 529     (let* ((start (event-start start-event))
 530            (end   (event-end   start-event))
 531            col ts)
 532       (when (eq start end) ;; mouse click
 533         (save-selected-window
 534           (select-window (posn-window start))
 535           (setq col (ruler-mode-window-col (car (posn-col-row start)))
 536                 ts  (+ col (window-hscroll)))
 537           (and (>= col 0) (< col (window-width))
 538                (member ts tab-stop-list)
 539                (progn
 540                  (message "Tab stop at %d deleted" ts)
 541                  (setq tab-stop-list (delete ts tab-stop-list)))))))))
 542
 543 (defun ruler-mode-toggle-show-tab-stops ()
 544   "Toggle showing of tab stops on the ruler."
 545   (interactive)
 546   (setq ruler-mode-show-tab-stops (not ruler-mode-show-tab-stops))
 547   (force-mode-line-update))
 548 \f
 549 (defvar ruler-mode-map
 550   (let ((km (make-sparse-keymap)))
 551     (define-key km [header-line down-mouse-1]
 552       #'ignore)
 553     (define-key km [header-line down-mouse-3]
 554       #'ignore)
 555     (define-key km [header-line down-mouse-2]
 556       #'ruler-mode-mouse-grab-any-column)
 557     (define-key km [header-line (shift down-mouse-1)]
 558       #'ruler-mode-mouse-set-left-margin)
 559     (define-key km [header-line (shift down-mouse-3)]
 560       #'ruler-mode-mouse-set-right-margin)
 561     (define-key km [header-line (control down-mouse-1)]
 562       #'ruler-mode-mouse-add-tab-stop)
 563     (define-key km [header-line (control down-mouse-3)]
 564       #'ruler-mode-mouse-del-tab-stop)
 565     (define-key km [header-line (control down-mouse-2)]
 566       #'ruler-mode-toggle-show-tab-stops)
 567     km)
 568   "Keymap for ruler minor mode.")
 569
 570 (defvar ruler-mode-header-line-format-old nil
 571   "Hold previous value of `header-line-format'.")
 572 (make-variable-buffer-local 'ruler-mode-header-line-format-old)
 573
 574 (defconst ruler-mode-header-line-format
 575   '(:eval (ruler-mode-ruler))
 576   "`header-line-format' used in ruler mode.")
 577
 578 ;;;###autoload
 579 (define-minor-mode ruler-mode
 580   "Display a ruler in the header line if ARG > 0."
 581   nil nil
 582   ruler-mode-map
 583   :group 'ruler-mode
 584   (if ruler-mode
 585       (progn
 586         ;; When `ruler-mode' is on save previous header line format
 587         ;; and install the ruler header line format.
 588         (when (local-variable-p 'header-line-format)
 589           (setq ruler-mode-header-line-format-old header-line-format))
 590         (setq header-line-format ruler-mode-header-line-format)
 591         (add-hook 'post-command-hook    ; add local hook
 592                   #'force-mode-line-update nil t))
 593     ;; When `ruler-mode' is off restore previous header line format if
 594     ;; the current one is the ruler header line format.
 595     (when (eq header-line-format ruler-mode-header-line-format)
 596       (kill-local-variable 'header-line-format)
 597       (when (local-variable-p 'ruler-mode-header-line-format-old)
 598         (setq header-line-format ruler-mode-header-line-format-old)))
 599     (remove-hook 'post-command-hook     ; remove local hook
 600                  #'force-mode-line-update t)))
 601 \f
 602 ;; Add ruler-mode to the minor mode menu in the mode line
 603 (define-key mode-line-mode-menu [ruler-mode]
 604   `(menu-item "Ruler" ruler-mode
 605               :button (:toggle . ruler-mode)))
 606
 607 (defconst ruler-mode-ruler-help-echo
 608   "\
 609 S-mouse-1/3: set L/R margin, \
 610 mouse-2: set goal column, \
 611 C-mouse-2: show tabs"
 612   "Help string shown when mouse is over the ruler.
 613 `ruler-mode-show-tab-stops' is nil.")
 614
 615 (defconst ruler-mode-ruler-help-echo-when-goal-column
 616   "\
 617 S-mouse-1/3: set L/R margin, \
 618 C-mouse-2: show tabs"
 619   "Help string shown when mouse is over the ruler.
 620 `goal-column' is set and `ruler-mode-show-tab-stops' is nil.")
 621
 622 (defconst ruler-mode-ruler-help-echo-when-tab-stops
 623   "\
 624 C-mouse1/3: set/unset tab, \
 625 C-mouse-2: hide tabs"
 626   "Help string shown when mouse is over the ruler.
 627 `ruler-mode-show-tab-stops' is non-nil.")
 628
 629 (defconst ruler-mode-fill-column-help-echo
 630   "drag-mouse-2: set fill column"
 631   "Help string shown when mouse is on the fill column character.")
 632
 633 (defconst ruler-mode-comment-column-help-echo
 634   "drag-mouse-2: set comment column"
 635   "Help string shown when mouse is on the comment column character.")
 636
 637 (defconst ruler-mode-goal-column-help-echo
 638   "\
 639 drag-mouse-2: set goal column, \
 640 mouse-2: unset goal column"
 641   "Help string shown when mouse is on the goal column character.")
 642
 643 (defconst ruler-mode-margin-help-echo
 644   "%s margin %S"
 645   "Help string shown when mouse is over a margin area.")
 646
 647 (defconst ruler-mode-fringe-help-echo
 648   "%s fringe %S"
 649   "Help string shown when mouse is over a fringe area.")
 650 \f
 651 (defun ruler-mode-ruler ()
 652   "Return a string ruler."
 653   (when ruler-mode
 654     (let* ((fullw (ruler-mode-full-window-width))
 655            (w     (window-width))
 656            (m     (window-margins))
 657            (lsb   (ruler-mode-left-scroll-bar-cols))
 658            (lf    (ruler-mode-left-fringe-cols))
 659            (lm    (or (car m) 0))
 660            (rsb   (ruler-mode-right-scroll-bar-cols))
 661            (rf    (ruler-mode-right-fringe-cols))
 662            (rm    (or (cdr m) 0))
 663            (ruler (make-string fullw ruler-mode-basic-graduation-char))
 664            (o     (+ lsb lf lm))
 665            (x     0)
 666            (i     o)
 667            (j     (window-hscroll))
 668            k c l1 l2 r2 r1 h1 h2 f1 f2)
 669
 670       ;; Setup the default properties.
 671       (put-text-property 0 fullw 'face 'ruler-mode-default-face ruler)
 672       (put-text-property 0 fullw
 673                          'help-echo
 674                          (cond
 675                           (ruler-mode-show-tab-stops
 676                            ruler-mode-ruler-help-echo-when-tab-stops)
 677                           (goal-column
 678                            ruler-mode-ruler-help-echo-when-goal-column)
 679                           (t
 680                            ruler-mode-ruler-help-echo))
 681                          ruler)
 682       ;; Setup the local map.
 683       (put-text-property 0 fullw 'local-map ruler-mode-map ruler)
 684
 685       ;; Setup the active area.
 686       (while (< x w)
 687         ;; Graduations.
 688         (cond
 689          ;; Show a number graduation.
 690          ((= (mod j 10) 0)
 691           (setq c (number-to-string (/ j 10))
 692                 m (length c)
 693                 k i)
 694           (put-text-property
 695            i (1+ i) 'face 'ruler-mode-column-number-face
 696            ruler)
 697           (while (and (> m 0) (>= k 0))
 698             (aset ruler k (aref c (setq m (1- m))))
 699             (setq k (1- k))))
 700          ;; Show an intermediate graduation.
 701          ((= (mod j 5) 0)
 702           (aset ruler i ruler-mode-inter-graduation-char)))
 703         ;; Special columns.
 704         (cond
 705          ;; Show the `current-column' marker.
 706          ((= j (current-column))
 707           (aset ruler i ruler-mode-current-column-char)
 708           (put-text-property
 709            i (1+ i) 'face 'ruler-mode-current-column-face
 710            ruler))
 711          ;; Show the `goal-column' marker.
 712          ((and goal-column (= j goal-column))
 713           (aset ruler i ruler-mode-goal-column-char)
 714           (put-text-property
 715            i (1+ i) 'face 'ruler-mode-goal-column-face
 716            ruler)
 717           (put-text-property
 718            i (1+ i) 'help-echo ruler-mode-goal-column-help-echo
 719            ruler))
 720          ;; Show the `comment-column' marker.
 721          ((= j comment-column)
 722           (aset ruler i ruler-mode-comment-column-char)
 723           (put-text-property
 724            i (1+ i) 'face 'ruler-mode-comment-column-face
 725            ruler)
 726           (put-text-property
 727            i (1+ i) 'help-echo ruler-mode-comment-column-help-echo
 728            ruler))
 729          ;; Show the `fill-column' marker.
 730          ((= j fill-column)
 731           (aset ruler i ruler-mode-fill-column-char)
 732           (put-text-property
 733            i (1+ i) 'face 'ruler-mode-fill-column-face
 734            ruler)
 735           (put-text-property
 736            i (1+ i) 'help-echo ruler-mode-fill-column-help-echo
 737            ruler))
 738          ;; Show the `tab-stop-list' markers.
 739          ((and ruler-mode-show-tab-stops (member j tab-stop-list))
 740           (aset ruler i ruler-mode-tab-stop-char)
 741           (put-text-property
 742            i (1+ i) 'face 'ruler-mode-tab-stop-face
 743            ruler)))
 744         (setq i (1+ i)
 745               j (1+ j)
 746               x (1+ x)))
 747
 748       ;; Highlight the fringes and margins.
 749       (if (nth 2 (window-fringes))
 750           ;; fringes outside margins.
 751           (setq l1 lf
 752                 l2 lm
 753                 r2 rm
 754                 r1 rf
 755                 h1 ruler-mode-fringe-help-echo
 756                 h2 ruler-mode-margin-help-echo
 757                 f1 'ruler-mode-fringes-face
 758                 f2 'ruler-mode-margins-face)
 759         ;; fringes inside margins.
 760         (setq l1 lm
 761               l2 lf
 762               r2 rf
 763               r1 rm
 764               h1 ruler-mode-margin-help-echo
 765               h2 ruler-mode-fringe-help-echo
 766               f1 'ruler-mode-margins-face
 767               f2 'ruler-mode-fringes-face))
 768       (setq i lsb j (+ i l1))
 769       (put-text-property i j 'face f1 ruler)
 770       (put-text-property i j 'help-echo (format h1 "Left" l1) ruler)
 771       (setq i j j (+ i l2))
 772       (put-text-property i j 'face f2 ruler)
 773       (put-text-property i j 'help-echo (format h2 "Left" l2) ruler)
 774       (setq i (+ o w) j (+ i r2))
 775       (put-text-property i j 'face f2 ruler)
 776       (put-text-property i j 'help-echo (format h2 "Right" r2) ruler)
 777       (setq i j j (+ i r1))
 778       (put-text-property i j 'face f1 ruler)
 779       (put-text-property i j 'help-echo (format h1 "Right" r1) ruler)
 780
 781       ;; Show inactive areas.
 782       (put-text-property 0 lsb   'face 'ruler-mode-pad-face ruler)
 783       (put-text-property j fullw 'face 'ruler-mode-pad-face ruler)
 784
 785       ;; Return the ruler propertized string.
 786       ruler)))
 787
 788 (provide 'ruler-mode)
 789
 790 ;; Local Variables:
 791 ;; coding: iso-latin-1
 792 ;; End:
 793
 794 ;;; arch-tag: b2f24546-5605-44c4-b67b-c9a4eeba3ee8
 795 ;;; ruler-mode.el ends here