;;; pp-c-l.el --- Display Control-l characters in a pretty way ;; ;; Filename: pp-c-l.el ;; Description: Display Control-l characters in a buffer in a pretty way ;; Author: Drew Adams ;; Maintainer: Drew Adams (concat "drew.adams" "@" "oracle" ".com") ;; Copyright (C) 2007-2025, Drew Adams, all rights reserved. ;; Created: Thu Feb 08 20:28:09 2007 ;; Version: 0 ;; Package-Requires: () ;; Last-Updated: Wed Jan 8 11:11:44 2025 (-0800) ;; By: dradams ;; Update #: 282 ;; URL: https://www.emacswiki.org/emacs/download/pp-c-l.el ;; Doc URL: https://emacswiki.org/emacs/PrettyControlL ;; Keywords: display, convenience, faces ;; Compatibility: GNU Emacs: 20.x, 21.x, 22.x, 23.x, 24.x, 25.x, 26.x ;; ;; Features that might be required by this library: ;; ;; None ;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; ;;; Commentary: ;; ;; Faces defined here: ;; ;; `pp^L-highlight'. ;; ;; User options defined here: ;; ;; `pp^L-^L-string', `pp^L-^L-string-function', ;; `pp^L-^L-string-post', `pp^L-^L-string-pre', ;; `pretty-control-l-mode'. ;; ;; Commands defined here: ;; ;; `pp^l', `pretty-control-l-mode', `refresh-pretty-control-l'. ;; ;; Non-interactive functions defined here: ;; ;; `pp^L-^L-display-table-entry', `pp^L-make-glyph-code'. ;; ;; ;; To use this library, add this to your initialization file ;; (~/.emacs or ~/_emacs): ;; ;; (require 'pp-c-l) ; Load this library. ;; ;; To turn on this mode by default, then either customize option ;; `pretty-control-l-mode' to non-nil or add this line also to your ;; init file: ;; ;; (pretty-control-l-mode 1) ; Turn on pretty display of `^L'. ;; ;; For most of the user options defined here, if you change the value ;; then you will need to re-enter `pretty-control-l-mode', for the ;; new value to take effect. ;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; ;;; Change Log: ;; ;; 2017/10/29 dadams ;; Address Emacs bug #29050: ;; pretty-control-l-mode: Add refresh-pretty-control-l to window-size-change-functions too. ;; refresh-pretty-control-l: Added unused optional arg. ;; 2011/01/04 dadams ;; Removed autoloads: non def* sexps & non-interactive fns. Added for defalias. ;; 2010/04/28 dadams ;; Added autoload cookie for pp^L-^L-display-table-entry. Thx to Peter Galbraith. ;; 2010/04/08 dadams ;; Added autoload cookies. Thx to Peter Galbraith. ;; 2009/03/02 dadams ;; Enhancement by Andrey Paramonov. ;; pp^L-^L-display-table-entry: Added window argument. ;; pretty-control-l-mode: Update display table of each window. ;; Add/remove refresh to window-configuration-hook. ;; refresh-pretty-control-l: Just call mode function when turned on. ;; 2009/02/26 dadams ;; Added: pp^L-^L-string-function, refresh-pretty-control-l. ;; pp^L-^L-display-table-entry: Use pp^L-^L-string-function if non-nil. ;; 2008/05/02 dadams ;; pp^L-make-glyph-code: If make-glyph-code exists, use that (alias). ;; 2007/05/28 dadams ;; pp^L-make-glyph-code: Reported Emacs 23 bug to Emacs. ;; Fixed to work also with Emacs 23+, per Kenichi Handa's suggestion. ;; 2007/02/08 dadams ;; Created. ;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; ;; 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., 51 Franklin Street, Fifth ;; Floor, Boston, MA 02110-1301, USA. ;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; ;;; Code: ;;;;;;;;;;;;;;;;;;;; ;; Quiet the byte-compiler (defvar pretty-control-l-mode) ;; Convenience function suggested by Kim Storm to [email protected], in response to ;; my email 2007-02-05, subject: "cannot understand Elisp manual node Glyphs". ;; Added to Emacs as `make-glyph-code' starting with Emacs 23. ;; The version here works also for Emacs versions before Emacs 23. ;; The constant passed as second arg to lsh must be the same as constant ;; CHARACTERBITS in `src/lisp.h'. (if (fboundp 'make-glyph-code) (defalias 'pp^L-make-glyph-code 'make-glyph-code) (defun pp^L-make-glyph-code (char &optional face) "Return a glyph code representing char CHAR with face FACE." (if face (logior char (lsh (face-id face) 19)) ; CHARACTERBITS char))) ;;;###autoload (defgroup Pretty-Control-L nil "Options to define pretty display of Control-l (`^L') characters." :prefix "pp^L-" :group 'convenience :group 'wp :link `(url-link :tag "Send Bug Report" ,(concat "mailto:" "drew.adams" "@" "oracle" ".com?subject=pp-c-l.el bug: \ &body=Describe bug here, starting with `emacs -q'. \ Don't forget to mention your Emacs and library versions.")) :link '(url-link :tag "Other Libraries by Drew" "https://www.emacswiki.org/emacs/DrewsElispLibraries") :link '(url-link :tag "Download" "https://www.emacswiki.org/emacs/download/pp-c-l.el") :link '(url-link :tag "Description" "https://www.emacswiki.org/emacs/PrettyControlL") :link '(emacs-commentary-link :tag "Commentary" "pp-c-l")) ;;;###autoload (defface pp^L-highlight (if (> emacs-major-version 21) '((((type x w32 mac graphic) (class color)) (:box (:line-width 3 :style pressed-button))) (t (:inverse-video t))) '((((type x w32 mac graphic) (class color)) (:foreground "Blue" :background "DarkSeaGreen1")) (t (:inverse-video t)))) "*Face used to highlight display-table entry for Control-l (`^L') char." :group 'Pretty-Control-L :group 'faces) ;;;###autoload (defcustom pp^L-^L-string " Section (Printable Page) " "*Highlighted string displayed in place of each Control-l (^L) character. If `pp^L-^L-string-function' is non-nil, then the string that function returns is used instead of `pp^L-^L-string'." :type 'string :group 'Pretty-Control-L) (defcustom pp^L-^L-string-function nil "*Function to produce string displayed in place of a Control-l (^L) char. The function accepts as argument the window where the ^L is displayed. If the option value is non-nil, option `pp^L-^L-string' is not used. You can use this option to have a dynamically defined display string. For example, this value displays a window-width horizontal line: (lambda (win) (make-string (1- (window-width win)) ?_))" :type '(choice (const :tag "None" nil) function) :group 'Pretty-Control-L) (defcustom pp^L-^L-string-pre (if (> emacs-major-version 21) "\n" "") "*String displayed just before `pp^L-^L-string'. This text is not highlighted." :type 'string :group 'Pretty-Control-L) (defcustom pp^L-^L-string-post "" "*String displayed just after `pp^L-^L-string'. This text is not highlighted." :type 'string :group 'convenience :group 'wp) (unless (fboundp 'define-minor-mode) ; Emacs 20. (defcustom pretty-control-l-mode nil "*Toggle pretty display of Control-l (`^L') characters. Setting this variable directly does not take effect; use either \\[customize] or command `pretty-control-l-mode'." :set (lambda (symbol value) (pretty-control-l-mode (if value 1 -1))) :initialize 'custom-initialize-default :type 'boolean :group 'Pretty-Control-L)) (defun pp^L-^L-display-table-entry (window) "Returns the display-table entry for Control-l (`^L') char in WINDOW. A vector determining how a Control-l character is displayed in WINDOW. Either a vector of characters or nil. The characters are displayed in place of the Control-l character. nil means `^L' is displayed. In effect, this concatenates `pp^L-^L-string-pre', `pp^L-^L-string', and `pp^L-^L-string-post'." (vconcat (mapconcat (lambda (c) (list c)) pp^L-^L-string-pre "") (mapcar (lambda (c) (pp^L-make-glyph-code c 'pp^L-highlight)) (if pp^L-^L-string-function (funcall pp^L-^L-string-function window) pp^L-^L-string)) (mapconcat (lambda (c) (list c)) pp^L-^L-string-post ""))) ;;;###autoload (defalias 'pp^l 'pretty-control-l-mode) (if (fboundp 'define-minor-mode) ;; Emacs 21 and later. ;; We eval this so that even if the library is byte-compiled with Emacs 20, ;; loading it into Emacs 21+ will define variable `pretty-control-l-mode'. (eval '(define-minor-mode pretty-control-l-mode "Toggle pretty display of Control-l (`^L') characters. With ARG, turn pretty display of `^L' on if and only if ARG is positive." :init-value nil :global t :group 'Pretty-Control-L :link `(url-link :tag "Send Bug Report" ,(concat "mailto:" "drew.adams" "@" "oracle" ".com?subject=\ pp-c-l.el bug: \ &body=Describe bug here, starting with `emacs -q'. \ Don't forget to mention your Emacs and library versions.")) :link '(url-link :tag "Other Libraries by Drew" "https://www.emacswiki.org/emacs/DrewsElispLibraries") :link '(url-link :tag "Download" "https://www.emacswiki.org/emacs/download/pp-c-l.el") :link '(url-link :tag "Description" "https://www.emacswiki.org/emacs/PrettyControlL") :link '(emacs-commentary-link :tag "Commentary" "pp-c-l") (cond (pretty-control-l-mode (add-hook 'window-configuration-change-hook 'refresh-pretty-control-l) (when (boundp 'window-size-change-functions) (add-hook 'window-size-change-functions 'refresh-pretty-control-l))) (t (remove-hook 'window-configuration-change-hook 'refresh-pretty-control-l) (when (boundp 'window-size-change-functions) (remove-hook 'window-size-change-functions 'refresh-pretty-control-l)))) (walk-windows (lambda (window) (let ((display-table (or (window-display-table window) (make-display-table)))) (aset display-table ?\014 (and pretty-control-l-mode (pp^L-^L-display-table-entry window))) (set-window-display-table window display-table))) 'no-minibuf 'visible))) ;; Emacs 20 (defun pretty-control-l-mode (&optional arg) "Toggle pretty display of Control-l (`^L') characters. With ARG, turn pretty display of `^L' on if and only if ARG is positive." (interactive "P") (setq pretty-control-l-mode (if arg (> (prefix-numeric-value arg) 0) (not pretty-control-l-mode))) (if pretty-control-l-mode (add-hook 'window-configuration-change-hook 'refresh-pretty-control-l) (remove-hook 'window-configuration-change-hook 'refresh-pretty-control-l)) (walk-windows (lambda (window) (let ((display-table (or (window-display-table window) (make-display-table)))) (aset display-table ?\014 (and pretty-control-l-mode (pp^L-^L-display-table-entry window))) (set-window-display-table window display-table))) 'no-minibuf 'visible))) ;;;###autoload (defun refresh-pretty-control-l (&optional _frame) "Reinitialize `pretty-control-l-mode', if on, to update the display." (interactive) (when pretty-control-l-mode (pretty-control-l-mode 1))) ;;;;;;;;;;;;;;;;;;;; (provide 'pp-c-l) ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;; pp-c-l.el ends here