;;; facemenu.el -- Create a face menu for interactively adding fonts to text
;; Copyright (c) 1994 Free Software Foundation, Inc.

;; Author: Boris Goldowsky <boris@cs.rochester.edu>
;; Keywords: faces

;; This file is part of GNU Emacs.

;; GNU Emacs 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.

;; GNU Emacs 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 GNU Emacs; see the file COPYING.  If not, write to
;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

;;; Commentary:
;; This file defines a menu of faces (bold, italic, etc) which allows you to
;; set the face used for a region of the buffer.  Some faces also have
;; keybindings, which are shown in the menu.  Faces with names beginning with
;; "fg:" or "bg:", as in "fg:red", are treated specially.
;; Such faces are assumed to consist only of a foreground (if "fg:") or
;; background (if "bg:") color.  They are thus put into the color submenus
;; rather than the general Face submenu.  These faces can also be
;; automatically created by selecting the "Other..." menu items in the
;; "Foreground" and "Background" submenus.
;;
;; The menu also contains submenus for indentation and justification-changing
;; commands.

;;; Usage:
;; Selecting a face from the menu or typing the keyboard equivalent will
;; change the region to use that face.  If you use transient-mark-mode and the
;; region is not active, the face will be remembered and used for the next
;; insertion.  It will be forgotten if you move point or make other
;; modifications before inserting or typing anything.
;;
;; Faces can be selected from the keyboard as well.  
;; The standard keybindings are M-g (or ESC g) + letter:
;; M-g i = "set italic",  M-g b = "set bold", etc.

;;; Customization:
;; An alternative set of keybindings that may be easier to type can be set up
;; using "Alt" or "Hyper" keys.  This requires that you either have or create
;; an Alt or Hyper key on your keyboard.  On my keyboard, there is a key
;; labeled "Alt", but to make it act as an Alt key I have to put this command
;; into my .xinitrc:
;;    xmodmap -e "add Mod3 = Alt_L"
;; Or, I can make it into a Hyper key with this:
;;    xmodmap -e "keysym Alt_L = Hyper_L" -e "add Mod2 = Hyper_L"
;; Check with local X-perts for how to do it on your system.
;; Then you can define your keybindings with code like this in your .emacs:
;;   (setq facemenu-keybindings
;;    '((default     . [?\H-d])
;;      (bold        . [?\H-b])
;;      (italic      . [?\H-i])
;;      (bold-italic . [?\H-l])
;;      (underline   . [?\H-u])))
;;   (setq facemenu-keymap global-map)
;;   (setq facemenu-key nil)
;;   (define-key global-map [?\H-c] 'facemenu-set-foreground) ; set fg color
;;   (define-key global-map [?\H-C] 'facemenu-set-background) ; set bg color
;;   (require 'facemenu)
;;
;; The order of the faces that appear in the menu and their keybindings can be
;; controlled by setting the variables `facemenu-keybindings' and
;; `facemenu-new-faces-at-end'.  List faces that you don't use in documents
;; (eg, `region') in `facemenu-unlisted-faces'.

;;; Known Problems:
;; Bold and Italic do not combine to create bold-italic if you select them
;; both, although most other combinations (eg bold + underline + some color)
;; do the intuitive thing.
;;
;; There is at present no way to display what the faces look like in
;; the menu itself.
;;
;; `list-faces-display' shows the faces in a different order than
;; this menu, which could be confusing.  I do /not/ sort the list
;; alphabetically, because I like the default order: it puts the most
;; basic, common fonts first.
;;
;; Please send me any other problems, comments or ideas.

;;; Code:

(provide 'facemenu)

(defvar facemenu-key "\M-g"
  "Prefix to use for facemenu commands.")

(defvar facemenu-keybindings
  '((default     . "d")
    (bold        . "b")
    (italic      . "i")
    (bold-italic . "l") ; {bold} intersect {italic} = {l}
    (underline   . "u"))
  "Alist of interesting faces and keybindings. 
Each element is itself a list: the car is the name of the face,
the next element is the key to use as a keyboard equivalent of the menu item;
the binding is made in facemenu-keymap.

The faces specifically mentioned in this list are put at the top of
the menu, in the order specified.  All other faces which are defined,
except for those in `facemenu-unlisted-faces', are listed after them, 
but get no keyboard equivalents.

If you change this variable after loading facemenu.el, you will need to call
`facemenu-update' to make it take effect.")

(defvar facemenu-new-faces-at-end t
  "Where in the menu to insert newly-created faces.
This should be nil to put them at the top of the menu, or t to put them
just before \"Other\" at the end.")

(defvar facemenu-unlisted-faces
  '(modeline region secondary-selection highlight scratch-face)
  "List of faces not to include in the Face menu.
Set this before loading facemenu.el, or call `facemenu-update' after
changing it.

If this variable is t, no faces will be added to the menu.  This is useful for
temporarily turning off the feature that automatically adds faces to the menu
when they are created.")

(defvar facemenu-face-menu
  (let ((map (make-sparse-keymap "Face")))
    (define-key map "o" (cons "Other..." 'facemenu-set-face))
    map)
  "Menu keymap for faces.")
(defalias 'facemenu-face-menu facemenu-face-menu)

(defvar facemenu-foreground-menu 
  (let ((map (make-sparse-keymap "Foreground Color")))
    (define-key map "o" (cons "Other" 'facemenu-set-foreground))
    map)
  "Menu keymap for foreground colors.")
(defalias 'facemenu-foreground-menu facemenu-foreground-menu)

(defvar facemenu-background-menu
  (let ((map (make-sparse-keymap "Background Color")))
    (define-key map "o" (cons "Other" 'facemenu-set-background))
    map)
  "Menu keymap for background colors")
(defalias 'facemenu-background-menu facemenu-background-menu)

(defvar facemenu-special-menu 
  (let ((map (make-sparse-keymap "Special")))
    (define-key map [read-only] (cons "Read-Only" 'facemenu-set-read-only))
    (define-key map [invisible] (cons "Invisible" 'facemenu-set-invisible))
    map)
  "Menu keymap for non-face text-properties.")
(defalias 'facemenu-special-menu facemenu-special-menu)

(defvar facemenu-justification-menu
  (let ((map (make-sparse-keymap "Justification")))
    (define-key map [?c] (cons "Center" 'set-justification-center))
    (define-key map [?b] (cons "Full" 'set-justification-full))
    (define-key map [?r] (cons "Right" 'set-justification-right))
    (define-key map [?l] (cons "Left" 'set-justification-left))
    (define-key map [?u] (cons "Unfilled" 'set-nofill))
    map)
  "Submenu for text justification commands.")
(defalias 'facemenu-justification-menu facemenu-justification-menu)

(defvar facemenu-indentation-menu
  (let ((map (make-sparse-keymap "Indentation")))
    (define-key map [UnIndentRight] 
      (cons "UnIndentRight" 'decrease-right-margin))
    (define-key map [IndentRight]
      (cons "IndentRight" 'increase-right-margin))
    (define-key map [Unindent]
      (cons "UnIndent" 'decrease-left-margin))
    (define-key map [Indent]
      (cons "Indent" 'increase-left-margin))
    map)
  "Submenu for indentation commands.")
(defalias 'facemenu-indentation-menu facemenu-indentation-menu)

(defvar facemenu-menu 
  (let ((map (make-sparse-keymap "Face")))
    (define-key map [dc] (cons "Display Colors" 'list-colors-display))
    (define-key map [df] (cons "Display Faces" 'list-faces-display))
    (define-key map [rm] (cons "Remove Props" 'facemenu-remove-all))
    (define-key map [s1] (list "-----------------"))
    (define-key map [in] (cons "Indentation" 'facemenu-indentation-menu))
    (define-key map [ju] (cons "Justification" 'facemenu-justification-menu))
    (define-key map [s2] (list "-----------------"))
    (define-key map [sp] (cons "Special Props" 'facemenu-special-menu))
    (define-key map [bg] (cons "Background Color" 'facemenu-background-menu))
    (define-key map [fg] (cons "Foreground Color" 'facemenu-foreground-menu))
    (define-key map [fc] (cons "Face" 'facemenu-face-menu))
    map)
  "Facemenu top-level menu keymap.")
(defalias 'facemenu-menu facemenu-menu)

(defvar facemenu-keymap 
  (let ((map (make-sparse-keymap "Set face")))
    (define-key map "o" (cons "Other" 'facemenu-set-face))
    map)
  "Map for keyboard face-changing commands.
`Facemenu-update' fills in the keymap according to the bindings
requested in `facemenu-keybindings'.")
(defalias 'facemenu-keymap facemenu-keymap)

;;; Internal Variables

(defvar facemenu-color-alist nil
  ;; Don't initialize here; that doesn't work if preloaded.
  "Alist of colors, used for completion.
If null, `facemenu-read-color' will set it.")

(defvar facemenu-loc nil)

(defun facemenu-update ()
  "Add or update the \"Face\" menu in the menu bar.
You can call this to update things if you change any of the menu configuration
variables."
  (interactive)
  
  ;; Global bindings:
  (define-key global-map [C-down-mouse-2] 'facemenu-menu)
  (if facemenu-key (define-key global-map facemenu-key 'facemenu-keymap))

  ;; Add each defined face to the menu.
  (facemenu-iterate 'facemenu-add-new-face
		    (facemenu-complete-face-list facemenu-keybindings)))

;;;###autoload
(defun facemenu-set-face (face &optional start end)
  "Add FACE to the region or next character typed.
It will be added to the top of the face list; any faces lower on the list that
will not show through at all will be removed.

Interactively, the face to be used is prompted for.
If the region is active, it will be set to the requested face.  If 
it is inactive \(even if mark-even-if-inactive is set) the next
character that is typed \(or otherwise inserted) will be set to
the the selected face.  Moving point or switching buffers before
typing a character cancels the request." 
  (interactive (list (read-face-name "Use face: ")))
  (barf-if-buffer-read-only)
  (facemenu-add-new-face face)
  (if mark-active
      (let ((start (or start (region-beginning)))
	    (end (or end (region-end))))
	(facemenu-add-face face start end))
    (facemenu-self-insert-face face)))

;;;###autoload
(defun facemenu-set-foreground (color &optional start end)
  "Set the foreground color of the region or next character typed.
The color is prompted for.  A face named `fg:color' is used \(or created).
If the region is active, it will be set to the requested face.  If
it is inactive \(even if mark-even-if-inactive is set) the next
character that is typed \(via `self-insert-command') will be set to
the the selected face.  Moving point or switching buffers before
typing a character cancels the request." 
  (interactive (list (facemenu-read-color "Foreground color: ")))
  (let ((face (intern (concat "fg:" color))))
    (or (facemenu-get-face face)
	(error "Unknown color: %s" color))
    (facemenu-set-face face start end)))

;;;###autoload
(defun facemenu-set-background (color &optional start end)
  "Set the background color of the region or next character typed.
The color is prompted for.  A face named `bg:color' is used \(or created).
If the region is active, it will be set to the requested face.  If
it is inactive \(even if mark-even-if-inactive is set) the next
character that is typed \(via `self-insert-command') will be set to
the the selected face.  Moving point or switching buffers before
typing a character cancels the request." 
  (interactive (list (facemenu-read-color "Background color: ")))
  (let ((face (intern (concat "bg:" color))))
    (or (facemenu-get-face face)
	(error "Unknown color: %s" color))
    (facemenu-set-face face start end)))

(defun facemenu-set-face-from-menu (face start end)
  "Set the face of the region or next character typed.
This function is designed to be called from a menu; the face to use
is the menu item's name.
If the region is active, it will be set to the requested face.  If
it is inactive \(even if mark-even-if-inactive is set) the next
character that is typed \(or otherwise inserted) will be set to
the the selected face.  Moving point or switching buffers before
typing a character cancels the request." 
  (interactive (list last-command-event
		     (if mark-active (region-beginning))
		     (if mark-active (region-end))))
  (barf-if-buffer-read-only)
  (facemenu-get-face face)
  (if start 
      (facemenu-add-face face start end)
    (facemenu-self-insert-face face)))

(defun facemenu-self-insert-face (face)
  (setq self-insert-face face
	self-insert-face-command this-command))

(defun facemenu-set-invisible (start end)
  "Make the region invisible.
This sets the `invisible' text property; it can be undone with
`facemenu-remove-all'."
  (interactive "r")
  (put-text-property start end 'invisible t))

(defun facemenu-set-intangible (start end)
  "Make the region intangible: disallow moving into it.
This sets the `intangible' text property; it can be undone with
`facemenu-remove-all'."
  (interactive "r")
  (put-text-property start end 'intangible t))

(defun facemenu-set-read-only (start end)
  "Make the region unmodifiable.
This sets the `read-only' text property; it can be undone with
`facemenu-remove-all'."
  (interactive "r")
  (put-text-property start end 'read-only t))

(defun facemenu-remove-all (start end)
  "Remove all text properties that facemenu added to region."
  (interactive "*r") ; error if buffer is read-only despite the next line.
  (let ((inhibit-read-only t))
    (remove-text-properties 
     start end '(face nil invisible nil intangible nil 
		      read-only nil category nil))))

;;;###autoload
(defun facemenu-read-color (prompt)
  "Read a color using the minibuffer."
  (let ((col (completing-read (or  "Color: ") 
			      (or facemenu-color-alist
				  (if (eq 'x window-system)
				      (mapcar 'list (x-defined-colors))))
			      nil t)))
    (if (equal "" col)
	nil
      col)))

;;;###autoload
(defun list-colors-display (&optional list)
  "Display colors.
You can optionally supply a LIST of colors to display, or this function will
get a list for the current display, removing alternate names for the same
color."
  (interactive)
  (if (and (null list) (eq 'x window-system))
      (let ((l (setq list (x-defined-colors))))
	(while (cdr l)
	  (if (facemenu-color-equal (car l) (car (cdr l)))
	      (setcdr l (cdr (cdr l)))
	    (setq l (cdr l))))))
  (with-output-to-temp-buffer "*Colors*"
    (save-excursion
      (set-buffer standard-output)
      (let ((facemenu-unlisted-faces t)
	    s)
	(while list
	  (setq s (point))
	  (insert (car list))
	  (indent-to 20)
	  (put-text-property s (point) 'face 
			     (facemenu-get-face 
			      (intern (concat "bg:" (car list)))))
	  (setq s (point))
	  (insert "  " (car list) "\n")
	  (put-text-property s (point) 'face 
			     (facemenu-get-face 
			      (intern (concat "fg:" (car list)))))
	  (setq list (cdr list)))))))

(defun facemenu-color-equal (a b)
  "Return t if colors A and B are the same color.
A and B should be strings naming colors.  The window-system server is queried
to find how they would actually be displayed.  Nil is always returned if the
correct answer cannot be determined."
  (cond ((equal a b) t)
	((and (eq 'x window-system)
	      (equal (x-color-values a) (x-color-values b))))))

(defun facemenu-add-face (face start end)
  "Add FACE to text between START and END.
For each section of that region that has a different face property, FACE will
be consed onto it, and other faces that are completely hidden by that will be
removed from the list.

As a special case, if FACE is `default', then the region is left with NO face
text property.  Otherwise, selecting the default face would not have any
effect."
  (interactive "*xFace:\nr")
  (if (eq face 'default)
      (remove-text-properties start end '(face default))
    (let ((part-start start) part-end)
      (while (not (= part-start end))
	(setq part-end (next-single-property-change part-start 'face nil end))
	(let ((prev (get-text-property part-start 'face)))
	  (put-text-property part-start part-end 'face
			     (if (null prev)
				 face
			       (facemenu-discard-redundant-faces
				(cons face
				      (if (listp prev) prev (list prev)))))))
	(setq part-start part-end)))))

(defun facemenu-discard-redundant-faces (face-list &optional mask)
  "Remove from FACE-LIST any faces that won't show at all.
This means they have no non-nil elements that aren't also non-nil in an
earlier face."
  (let ((useful nil))
    (cond ((null face-list) nil)
	  ((null mask)
	   (cons (car face-list)
		 (facemenu-discard-redundant-faces
		  (cdr face-list) 
		  (copy-sequence (internal-get-face (car face-list))))))
	  ((let ((i (length mask))
		 (face (internal-get-face (car face-list))))
	     (while (>= (setq i (1- i)) 0)
	       (if (and (aref face i)
			(not (aref mask i)))
		   (progn (setq useful t)
			  (aset mask i t))))
	     useful)
	   (cons (car face-list)
		 (facemenu-discard-redundant-faces (cdr face-list) mask)))
	  (t (facemenu-discard-redundant-faces (cdr face-list) mask)))))

(defun facemenu-get-face (symbol)
  "Make sure FACE exists.
If not, it is created.  If it is created and is of the form `fg:color', then
set the foreground to that color. If of the form `bg:color', set the
background.  In any case, add it to the appropriate menu.  Returns the face,
or nil if given a bad color."
  (if (or (internal-find-face symbol)
	  (let* ((face (make-face symbol))
		 (name (symbol-name symbol))
		 (color (substring name 3)))
	    (cond ((string-match "^fg:" name)
		   (set-face-foreground face color)
		   (and (eq 'x window-system) (x-color-defined-p color)))
		  ((string-match "^bg:" name)
		   (set-face-background face color)
		   (and (eq 'x window-system) (x-color-defined-p color)))
		  (t))))
      symbol))

(defun facemenu-add-new-face (face)
  "Add a FACE to the appropriate Face menu.
Automatically called when a new face is created."
  (let* ((name (symbol-name face))
	 (menu (cond ((string-match "^fg:" name) 
		      (setq name (substring name 3))
		      'facemenu-foreground-menu)
		     ((string-match "^bg:" name) 
		      (setq name (substring name 3))
		      'facemenu-background-menu)
		     (t 'facemenu-face-menu)))
	 (key (cdr (assoc face facemenu-keybindings)))
	 function menu-val)
    (cond ((eq t facemenu-unlisted-faces))
	  ((memq face facemenu-unlisted-faces))
	  (key ; has a keyboard equivalent.  These go at the front.
	   (setq function (intern (concat "facemenu-set-" name)))
	   (fset function
		 (` (lambda () (interactive)
		      (facemenu-set-face (quote (, face))))))
	   (define-key 'facemenu-keymap key (cons name function))
	   (define-key menu key (cons name function)))
	  ((facemenu-iterate ; check if equivalent face is already in the menu
	    (lambda (m) (and (listp m) 
			     (symbolp (car m))
			     (face-equal (car m) face)))
	    (cdr (symbol-function menu))))
	  (t   ; No keyboard equivalent.  Figure out where to put it:
	   (setq key (vector face)
		 function 'facemenu-set-face-from-menu
		 menu-val (symbol-function menu))
	   (if (and facemenu-new-faces-at-end
		   (> (length menu-val) 3))
	       (define-key-after menu-val key (cons name function)
		 (car (nth (- (length menu-val) 3) menu-val)))
	     (define-key menu key (cons name function))))))
  nil) ; Return nil for facemenu-iterate

(defun facemenu-complete-face-list (&optional oldlist)
  "Return list of all faces that are look different.
Starts with given ALIST of faces, and adds elements only if they display 
differently from any face already on the list.
The faces on ALIST will end up at the end of the returned list, in reverse 
order."
  (let ((list (nreverse (mapcar 'car oldlist))))
    (facemenu-iterate 
     (lambda (new-face) 
       (if (not (memq new-face list))
	   (setq list (cons new-face list)))
       nil)
     (nreverse (face-list)))
    list))

(defun facemenu-iterate (func iterate-list)
  "Apply FUNC to each element of LIST until one returns non-nil.
Returns the non-nil value it found, or nil if all were nil."
  (while (and iterate-list (not (funcall func (car iterate-list))))
    (setq iterate-list (cdr iterate-list)))
  (car iterate-list))

(facemenu-update)

;;; facemenu.el ends here