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emacs/lisp/ruler-mode.el
2001-10-09 12:10:17 +00:00

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;;; ruler-mode.el --- Display a ruler in the header line
;; Copyright (C) 2001 Free Software Foundation, Inc.
;; Author: David Ponce <david@dponce.com>
;; Maintainer: David Ponce <david@dponce.com>
;; Created: 24 Mar 2001
;; Version: 1.3.1
;; Keywords: environment
;; This file is part of GNU Emacs.
;; This program is free software; you can redistribute it and/or
;; modify it under the terms of the GNU General Public License as
;; published by the Free Software Foundation; either version 2, or (at
;; your option) any later version.
;; This program is distributed in the hope that it will be useful, but
;; WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
;; General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with this program; see the file COPYING. If not, write to
;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.
;;; Commentary:
;; This library provides a minor mode to display a ruler in the header
;; line. It works only on Emacs 21.
;;
;; You can use the mouse to change the `fill-column', `window-margins'
;; and `tab-stop-list' settings:
;;
;; [header-line (shift down-mouse-1)] set left margin to the ruler
;; graduation where the mouse pointer is on.
;;
;; [header-line (shift down-mouse-3)] set right margin to the ruler
;; graduation where the mouse pointer is on.
;;
;; [header-line down-mouse-2] set `fill-column' to the ruler
;; graduation where the mouse pointer is on.
;;
;; [header-line (control down-mouse-1)] add a tab stop to the ruler
;; graduation where the mouse pointer is on.
;;
;; [header-line (control down-mouse-3)] remove the tab stop at the
;; ruler graduation where the mouse pointer is on.
;;
;; [header-line (control down-mouse-2)] or M-x
;; `ruler-mode-toggle-show-tab-stops' toggle showing and visually
;; editing `tab-stop-list' setting. The `ruler-mode-show-tab-stops'
;; option controls if the ruler shows tab stops by default.
;;
;; In the ruler the character `ruler-mode-current-column-char' shows
;; the `current-column' location, `ruler-mode-fill-column-char' shows
;; the `fill-column' location and `ruler-mode-tab-stop-char' shows tab
;; stop locations. `window-margins' areas are shown with a different
;; background color.
;;
;; It is also possible to customize the following characters:
;;
;; - `ruler-mode-margins-char' character used to pad margin areas
;; (space by default).
;; - `ruler-mode-basic-graduation-char' character used for basic
;; graduations ('.' by default).
;; - `ruler-mode-inter-graduation-char' character used for
;; intermediate graduations ('!' by default).
;;
;; The following faces are customizable:
;;
;; - `ruler-mode-default-face' the ruler default face.
;; - `ruler-mode-fill-column-face' the face used to highlight the
;; `fill-column' character.
;; - `ruler-mode-current-column-face' the face used to highlight the
;; `current-column' character.
;; - `ruler-mode-tab-stop-face' the face used to highlight tab stop
;; characters.
;; - `ruler-mode-margins-face' the face used to highlight the
;; `window-margins' areas.
;; - `ruler-mode-column-number-face' the face used to highlight the
;; number graduations.
;;
;; `ruler-mode-default-face' inherits from the built-in `default' face.
;; All `ruler-mode' faces inerit from `ruler-mode-default-face'.
;;
;; WARNING: To keep ruler graduations aligned on text columns it is
;; important to use the same font family and size for ruler and text
;; areas.
;; Installation
;;
;; To automatically display the ruler in specific major modes use:
;;
;; (add-hook '<major-mode>-hook 'ruler-mode)
;;
;;; History:
;;
;;; Code:
(eval-when-compile
(require 'wid-edit))
(defgroup ruler-mode nil
"Display a ruler in the header line."
:version "21.2"
:group 'environment)
(defcustom ruler-mode-show-tab-stops nil
"*If non-nil the ruler shows tab stop positions.
Also allowing to visually change `tab-stop-list' setting using
<C-down-mouse-1> and <C-down-mouse-3> on the ruler to respectively add
or remove a tab stop. \\[ruler-mode-toggle-show-tab-stops] or
<C-down-mouse-2> on the ruler toggles showing/editing of tab stops."
:group 'ruler-mode
:type 'boolean)
;; IMPORTANT: This function must be defined before the following
;; defcustoms because it is used in their :validate clause.
(defun ruler-mode-character-validate (widget)
"Ensure WIDGET value is a valid character value."
(save-excursion
(let ((value (widget-value widget)))
(if (char-valid-p value)
nil
(widget-put widget :error
(format "Invalid character value: %S" value))
widget))))
(defcustom ruler-mode-fill-column-char (if window-system
?\<5C>
?\|)
"*Character used at the `fill-column' location."
:group 'ruler-mode
:type '(choice
(character :tag "Character")
(integer :tag "Integer char value"
:validate ruler-mode-character-validate)))
(defcustom ruler-mode-current-column-char (if window-system
?\<5C>
?\@)
"*Character used at the `current-column' location."
:group 'ruler-mode
:type '(choice
(character :tag "Character")
(integer :tag "Integer char value"
:validate ruler-mode-character-validate)))
(defcustom ruler-mode-tab-stop-char ?\T
"*Character used at `tab-stop-list' locations."
:group 'ruler-mode
:type '(choice
(character :tag "Character")
(integer :tag "Integer char value"
:validate ruler-mode-character-validate)))
(defcustom ruler-mode-margins-char ?\
"*Character used in margin areas."
:group 'ruler-mode
:type '(choice
(character :tag "Character")
(integer :tag "Integer char value"
:validate ruler-mode-character-validate)))
(defcustom ruler-mode-basic-graduation-char ?\.
"*Character used for basic graduations."
:group 'ruler-mode
:type '(choice
(character :tag "Character")
(integer :tag "Integer char value"
:validate ruler-mode-character-validate)))
(defcustom ruler-mode-inter-graduation-char ?\!
"*Character used for intermediate graduations."
:group 'ruler-mode
:type '(choice
(character :tag "Character")
(integer :tag "Integer char value"
:validate ruler-mode-character-validate)))
(defface ruler-mode-default-face
'((((type tty))
(:inherit default
:background "grey64"
:foreground "grey50"
))
(t
(:inherit default
:background "grey76"
:foreground "grey64"
:box (:color "grey76"
:line-width 1
:style released-button)
)))
"Default face used by the ruler."
:group 'ruler-mode)
(defface ruler-mode-column-number-face
'((t
(:inherit ruler-mode-default-face
:foreground "black"
)))
"Face used to highlight number graduations."
:group 'ruler-mode)
(defface ruler-mode-fill-column-face
'((t
(:inherit ruler-mode-default-face
:foreground "red"
)))
"Face used to highlight the fill column character."
:group 'ruler-mode)
(defface ruler-mode-tab-stop-face
'((t
(:inherit ruler-mode-default-face
:foreground "steelblue"
)))
"Face used to highlight tab stop characters."
:group 'ruler-mode)
(defface ruler-mode-margins-face
'((((type tty))
(:inherit ruler-mode-default-face
:background "grey50"
))
(t
(:inherit ruler-mode-default-face
:background "grey64"
)))
"Face used to highlight the `window-margins' areas."
:group 'ruler-mode)
(defface ruler-mode-current-column-face
'((t
(:inherit ruler-mode-default-face
:weight bold
:foreground "yellow"
)))
"Face used to highlight the `current-column' character."
:group 'ruler-mode)
(defun ruler-mode-mouse-set-left-margin (start-event)
"Set left margin to the graduation where the mouse pointer is on.
START-EVENT is the mouse click event."
(interactive "e")
(let* ((start (event-start start-event))
(end (event-end start-event))
w col m lm0 lm rm)
(if (eq start end) ;; mouse click
(save-selected-window
(select-window (posn-window start))
(setq m (window-margins)
lm0 (or (car m) 0)
rm (or (cdr m) 0)
w (window-width)
col (car (posn-col-row start))
lm (min (- w rm) col))
(message "Left margin set to %d (was %d)" lm lm0)
(set-window-margins nil lm rm)))))
(defun ruler-mode-mouse-set-right-margin (start-event)
"Set right margin to the graduation where the mouse pointer is on.
START-EVENT is the mouse click event."
(interactive "e")
(let* ((start (event-start start-event))
(end (event-end start-event))
m col w lm rm0 rm)
(if (eq start end) ;; mouse click
(save-selected-window
(select-window (posn-window start))
(setq m (window-margins)
rm0 (or (cdr m) 0)
lm (or (car m) 0)
col (car (posn-col-row start))
w (window-width)
rm (max 0 (- w col)))
(message "Right margin set to %d (was %d)" rm rm0)
(set-window-margins nil lm rm)))))
(defun ruler-mode-mouse-set-fill-column (start-event)
"Set `fill-column' to the graduation where the mouse pointer is on.
START-EVENT is the mouse click event."
(interactive "e")
(let* ((start (event-start start-event))
(end (event-end start-event))
m col w lm rm hs fc)
(if (eq start end) ;; mouse click
(save-selected-window
(select-window (posn-window start))
(setq m (window-margins)
lm (or (car m) 0)
rm (or (cdr m) 0)
col (- (car (posn-col-row start)) lm)
w (window-width)
hs (window-hscroll)
fc (+ col hs))
(and (>= col 0) (< (+ col lm rm) w)
(progn
(message "Fill column set to %d (was %d)" fc fill-column)
(setq fill-column fc)))))))
(defun ruler-mode-mouse-add-tab-stop (start-event)
"Add a tab stop to the graduation where the mouse pointer is on.
START-EVENT is the mouse click event."
(interactive "e")
(if ruler-mode-show-tab-stops
(let* ((start (event-start start-event))
(end (event-end start-event))
m col w lm rm hs ts)
(if (eq start end) ;; mouse click
(save-selected-window
(select-window (posn-window start))
(setq m (window-margins)
lm (or (car m) 0)
rm (or (cdr m) 0)
col (- (car (posn-col-row start)) lm)
w (window-width)
hs (window-hscroll)
ts (+ col hs))
(and (>= col 0) (< (+ col lm rm) w)
(not (member ts tab-stop-list))
(progn
(message "Tab stop set to %d" ts)
(setq tab-stop-list
(sort (cons ts tab-stop-list)
#'<)))))))))
(defun ruler-mode-mouse-del-tab-stop (start-event)
"Delete tab stop at the graduation where the mouse pointer is on.
START-EVENT is the mouse click event."
(interactive "e")
(if ruler-mode-show-tab-stops
(let* ((start (event-start start-event))
(end (event-end start-event))
m col w lm rm hs ts)
(if (eq start end) ;; mouse click
(save-selected-window
(select-window (posn-window start))
(setq m (window-margins)
lm (or (car m) 0)
rm (or (cdr m) 0)
col (- (car (posn-col-row start)) lm)
w (window-width)
hs (window-hscroll)
ts (+ col hs))
(and (>= col 0) (< (+ col lm rm) w)
(member ts tab-stop-list)
(progn
(message "Tab stop at %d deleted" ts)
(setq tab-stop-list
(delete ts tab-stop-list)))))))))
(defun ruler-mode-toggle-show-tab-stops ()
"Toggle showing of tab stops on the ruler."
(interactive)
(when ruler-mode
(setq ruler-mode-show-tab-stops (not ruler-mode-show-tab-stops))
(force-mode-line-update)))
(defvar ruler-mode-map
(let ((km (make-sparse-keymap)))
(define-key km [header-line down-mouse-1]
#'ignore)
(define-key km [header-line down-mouse-3]
#'ignore)
(define-key km [header-line down-mouse-2]
#'ruler-mode-mouse-set-fill-column)
(define-key km [header-line (shift down-mouse-1)]
#'ruler-mode-mouse-set-left-margin)
(define-key km [header-line (shift down-mouse-3)]
#'ruler-mode-mouse-set-right-margin)
(define-key km [header-line (control down-mouse-1)]
#'ruler-mode-mouse-add-tab-stop)
(define-key km [header-line (control down-mouse-3)]
#'ruler-mode-mouse-del-tab-stop)
(define-key km [header-line (control down-mouse-2)]
#'ruler-mode-toggle-show-tab-stops)
km)
"Keymap for ruler minor mode.")
(defvar ruler-mode-header-line-format-old nil
"Hold previous value of `header-line-format'.")
(make-variable-buffer-local 'ruler-mode-header-line-format-old)
(defconst ruler-mode-header-line-format
'(:eval (ruler-mode-ruler))
"`header-line-format' used in ruler mode.")
;;;###autoload
(define-minor-mode ruler-mode
"Display a ruler in the header line if ARG > 0."
nil nil
ruler-mode-map
:group 'ruler-mode
(if ruler-mode
(progn
;; When `ruler-mode' is on save previous header line format
;; and install the ruler header line format.
(setq ruler-mode-header-line-format-old header-line-format
header-line-format ruler-mode-header-line-format)
(add-hook 'post-command-hook ; add local hook
#'force-mode-line-update nil t))
;; When `ruler-mode' is off restore previous header line format if
;; the current one is the ruler header line format.
(if (eq header-line-format ruler-mode-header-line-format)
(setq header-line-format ruler-mode-header-line-format-old))
(remove-hook 'post-command-hook ; remove local hook
#'force-mode-line-update t)))
;; Add ruler-mode to the the minor mode menu in the mode line
(define-key mode-line-mode-menu [ruler-mode]
`(menu-item "Ruler" ruler-mode
:button (:toggle . ruler-mode)))
(defconst ruler-mode-ruler-help-echo
"\
S-mouse-1/3: set L/R margin, \
mouse-2: set fill col, \
C-mouse-2: show tabs"
"Help string shown when mouse pointer is over the ruler.
`ruler-mode-show-tab-stops' is nil.")
(defconst ruler-mode-ruler-help-echo-tab
"\
C-mouse1/3: set/unset tab, \
C-mouse-2: hide tabs"
"Help string shown when mouse pointer is over the ruler.
`ruler-mode-show-tab-stops' is non-nil.")
(defconst ruler-mode-left-margin-help-echo
"Left margin %S"
"Help string shown when mouse is over the left margin area.")
(defconst ruler-mode-right-margin-help-echo
"Right margin %S"
"Help string shown when mouse is over the right margin area.")
(defvar ruler-mode-left-fringe-cols nil
"Hold last result of function `ruler-mode-left-fringe-cols'.
This cache is local to each frame.")
(make-variable-frame-local 'ruler-mode-left-fringe-cols)
(defun ruler-mode-left-fringe-cols (&optional check)
"Return the character width of fringe and left vertical scrollbar.
That is a pair (FRINGE-COLS . VSCROLLBAR-COLS) where:
- - FRINGE-COLS is the number of columns occupied by a fringe area.
- - VSCROLLBAR-COLS is the number of columns occupied by the left
vertical scrollbar or 0 if there is no vertical scrollbar on the
left side.
The first time this function is called its result is saved in a frame
local cache and then returned on next calls. If optional argument
CHECK is non-nil or if the frame 'vertical-scroll-bars parameter has
been changed the function re-computes the result."
(let* ((f (selected-frame))
(vsb (frame-parameter f 'vertical-scroll-bars))
(lfc (frame-parameter f 'ruler-mode-left-fringe-cols)))
(if (or check (not (eq (cdr lfc) vsb)))
(let* ((w (frame-first-window f))
(sbw (frame-pixel-width f))
(chw (frame-char-width f))
(chx (/ 1.0 (float chw)))
(pos (cons 0.0 0))
(lfw 0.0)
coord)
(if vsb
(modify-frame-parameters
f '((vertical-scroll-bars . nil))))
(setq coord (coordinates-in-window-p pos w))
(while (not (memq coord '(left-fringe mode-line)))
(setcdr pos (1+ (cdr pos)))
(setq coord (coordinates-in-window-p pos w)))
(while (eq coord 'left-fringe)
(setcar pos (+ (car pos) chx))
(setq lfw (+ lfw chx)
coord (coordinates-in-window-p pos w)))
(or vsb
(modify-frame-parameters
f '((vertical-scroll-bars . right))))
(setq sbw (/ (abs (- sbw (frame-pixel-width f))) chw)
lfw (floor lfw))
(setq lfc (cons (cons lfw (if (eq vsb 'left) sbw 0)) vsb))
(modify-frame-parameters
f (list (cons 'vertical-scroll-bars vsb)
(cons 'ruler-mode-left-fringe-cols lfc)))))
(car lfc)))
(defun ruler-mode-ruler ()
"Return a string ruler."
(if ruler-mode
(let* ((lfr (ruler-mode-left-fringe-cols))
(w (+ (window-width) 1 (cdr lfr)))
(m (window-margins))
(l (or (car m) 0))
(r (or (cdr m) 0))
(j (+ (car lfr) (cdr lfr)))
(o (- (window-hscroll) l j))
(i 0)
(ruler (concat
;; unit graduations
(make-string w ruler-mode-basic-graduation-char)
;; extra space to fill the header line
(make-string j ?\ )))
c k)
;; Setup default face and help echo.
(put-text-property 0 (length ruler)
'face 'ruler-mode-default-face
ruler)
(put-text-property 0 (length ruler)
'help-echo
(if ruler-mode-show-tab-stops
ruler-mode-ruler-help-echo-tab
ruler-mode-ruler-help-echo)
ruler)
;; Setup the local map.
(put-text-property 0 (length ruler)
'local-map ruler-mode-map
ruler)
(setq j (+ l j))
;; Setup the left margin area.
(put-text-property
i j 'face 'ruler-mode-margins-face
ruler)
(put-text-property
i j 'help-echo (format ruler-mode-left-margin-help-echo l)
ruler)
(while (< i j)
(aset ruler i ruler-mode-margins-char)
(setq i (1+ i)))
;; Setup the ruler area.
(setq r (- w r))
(while (< i r)
(setq j (+ i o))
(cond
((= (mod j 10) 0)
(setq c (number-to-string (/ j 10))
m (length c)
k i)
(put-text-property
i (1+ i) 'face 'ruler-mode-column-number-face
ruler)
(while (and (> m 0) (>= k 0))
(aset ruler k (aref c (setq m (1- m))))
(setq k (1- k)))
)
((= (mod j 5) 0)
(aset ruler i ruler-mode-inter-graduation-char)
)
)
(setq i (1+ i)))
;; Setup the right margin area.
(put-text-property
i (length ruler) 'face 'ruler-mode-margins-face
ruler)
(put-text-property
i (length ruler) 'help-echo
(format ruler-mode-right-margin-help-echo (- w r))
ruler)
(while (< i (length ruler))
(aset ruler i ruler-mode-margins-char)
(setq i (1+ i)))
;; Show the `fill-column' marker.
(setq i (- fill-column o))
(and (>= i 0) (< i r)
(aset ruler i ruler-mode-fill-column-char)
(put-text-property
i (1+ i) 'face 'ruler-mode-fill-column-face
ruler))
;; Show the `tab-stop-list' markers.
(if ruler-mode-show-tab-stops
(let ((tsl tab-stop-list) ts)
(while tsl
(setq ts (car tsl)
tsl (cdr tsl)
i (- ts o))
(and (>= i 0) (< i r)
(aset ruler i ruler-mode-tab-stop-char)
(put-text-property
i (1+ i)
'face (cond
;; Don't override the fill-column face
((eq ts fill-column)
'ruler-mode-fill-column-face)
(t
'ruler-mode-tab-stop-face))
ruler)))))
;; Show the `current-column' marker.
(setq i (- (current-column) o))
(and (>= i 0) (< i r)
(aset ruler i ruler-mode-current-column-char)
(put-text-property
i (1+ i) 'face 'ruler-mode-current-column-face
ruler))
ruler)))
(provide 'ruler-mode)
;; Local Variables:
;; coding: iso-latin-1
;; End:
;;; ruler-mode.el ends here