lisp/tooltip.el

   1 ;;; tooltip.el --- show tooltip windows
   2
   3 ;; Copyright (C) 1997, 1999-2011 Free Software Foundation, Inc.
   4
   5 ;; Author: Gerd Moellmann <gerd@acm.org>
   6 ;; Keywords: help c mouse tools
   7 ;; Package: emacs
   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 3 of the License, or
  14 ;; (at your option) 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.  If not, see <http://www.gnu.org/licenses/>.
  23
  24 ;;; Commentary:
  25
  26 ;;; Code:
  27
  28 (defvar comint-prompt-regexp)
  29
  30 (defgroup tooltip nil
  31   "Customization group for the `tooltip' package."
  32   :group 'help
  33   :group 'gud
  34   :group 'mouse
  35   :group 'tools
  36   :version "21.1"
  37   :tag "Tool Tips")
  38 \f
  39 ;;; Switching tooltips on/off
  40
  41 (define-minor-mode tooltip-mode
  42   "Toggle Tooltip mode.
  43 With ARG, turn Tooltip mode on if and only if ARG is positive.
  44 When this minor mode is enabled, Emacs displays help text
  45 in a pop-up window for buttons and menu items that you put the mouse on.
  46 \(However, if `tooltip-use-echo-area' is non-nil, this and
  47 all pop-up help appears in the echo area.)
  48
  49 When Tooltip mode is disabled, Emacs displays one line of
  50 the help text in the echo area, and does not make a pop-up window."
  51   :global t
  52   ;; Even if we start on a text-only terminal, make this non-nil by
  53   ;; default because we can open a graphical frame later (multi-tty).
  54   :init-value t
  55   :initialize 'custom-initialize-delay
  56   :group 'tooltip
  57   (unless (or (null tooltip-mode) (fboundp 'x-show-tip))
  58     (error "Sorry, tooltips are not yet available on this system"))
  59   (if tooltip-mode
  60       (progn
  61         (add-hook 'pre-command-hook 'tooltip-hide)
  62         (add-hook 'tooltip-functions 'tooltip-help-tips))
  63     (unless (and (boundp 'gud-tooltip-mode) gud-tooltip-mode)
  64       (remove-hook 'pre-command-hook 'tooltip-hide))
  65     (remove-hook 'tooltip-functions 'tooltip-help-tips))
  66   (setq show-help-function
  67         (if tooltip-mode 'tooltip-show-help 'tooltip-show-help-non-mode)))
  68
  69 \f
  70 ;;; Customizable settings
  71
  72 (defcustom tooltip-delay 0.7
  73   "Seconds to wait before displaying a tooltip the first time."
  74   :type 'number
  75   :group 'tooltip)
  76
  77 (defcustom tooltip-short-delay 0.1
  78   "Seconds to wait between subsequent tooltips on different items."
  79   :type 'number
  80   :group 'tooltip)
  81
  82 (defcustom tooltip-recent-seconds 1
  83   "Display tooltips if changing tip items within this many seconds.
  84 Do so after `tooltip-short-delay'."
  85   :type 'number
  86   :group 'tooltip)
  87
  88 (defcustom tooltip-hide-delay 10
  89   "Hide tooltips automatically after this many seconds."
  90   :type 'number
  91   :group 'tooltip)
  92
  93 (defcustom tooltip-x-offset 5
  94   "X offset, in pixels, for the display of tooltips.
  95 The offset is the distance between the X position of the mouse and
  96 the left border of the tooltip window.  It must be chosen so that the
  97 tooltip window doesn't contain the mouse when it pops up, or it may
  98 interfere with clicking where you wish.
  99
 100 If `tooltip-frame-parameters' includes the `left' parameter,
 101 the value of `tooltip-x-offset' is ignored."
 102   :type 'integer
 103   :group 'tooltip)
 104
 105 (defcustom tooltip-y-offset +20
 106   "Y offset, in pixels, for the display of tooltips.
 107 The offset is the distance between the Y position of the mouse and
 108 the top border of the tooltip window.  It must be chosen so that the
 109 tooltip window doesn't contain the mouse when it pops up, or it may
 110 interfere with clicking where you wish.
 111
 112 If `tooltip-frame-parameters' includes the `top' parameter,
 113 the value of `tooltip-y-offset' is ignored."
 114   :type 'integer
 115   :group 'tooltip)
 116
 117 (defcustom tooltip-frame-parameters
 118   '((name . "tooltip")
 119     (internal-border-width . 2)
 120     (border-width . 1))
 121   "Frame parameters used for tooltips.
 122
 123 If `left' or `top' parameters are included, they specify the absolute
 124 position to pop up the tooltip.
 125
 126 Note that font and color parameters are ignored, and the attributes
 127 of the `tooltip' face are used instead."
 128   :type 'sexp
 129   :group 'tooltip)
 130
 131 (defface tooltip
 132   '((((class color))
 133      :background "lightyellow"
 134      :foreground "black"
 135      :inherit variable-pitch)
 136     (t
 137      :inherit variable-pitch))
 138   "Face for tooltips."
 139   :group 'tooltip
 140   :group 'basic-faces)
 141
 142 (defcustom tooltip-use-echo-area nil
 143   "Use the echo area instead of tooltip frames for help and GUD tooltips.
 144 To display multi-line help text in the echo area, set this to t
 145 and enable `tooltip-mode'."
 146   :type 'boolean
 147   :group 'tooltip)
 148
 149 \f
 150 ;;; Variables that are not customizable.
 151
 152 (defvar tooltip-functions nil
 153   "Functions to call to display tooltips.
 154 Each function is called with one argument EVENT which is a copy
 155 of the last mouse movement event that occurred.  If one of these
 156 functions displays the tooltip, it should return non-nil and the
 157 rest are not called.")
 158
 159 (define-obsolete-variable-alias 'tooltip-hook 'tooltip-functions "23.1")
 160
 161 (defvar tooltip-timeout-id nil
 162   "The id of the timeout started when Emacs becomes idle.")
 163
 164 (defvar tooltip-last-mouse-motion-event nil
 165   "A copy of the last mouse motion event seen.")
 166
 167 (defvar tooltip-hide-time nil
 168   "Time when the last tooltip was hidden.")
 169
 170 (defvar gud-tooltip-mode) ;; Prevent warning.
 171
 172 ;;; Event accessors
 173
 174 (defun tooltip-event-buffer (event)
 175   "Return the buffer over which event EVENT occurred.
 176 This might return nil if the event did not occur over a buffer."
 177   (let ((window (posn-window (event-end event))))
 178     (and window (window-buffer window))))
 179
 180 \f
 181 ;;; Timeout for tooltip display
 182
 183 (defun tooltip-delay ()
 184   "Return the delay in seconds for the next tooltip."
 185   (if (and tooltip-hide-time
 186            (< (- (float-time) tooltip-hide-time) tooltip-recent-seconds))
 187       tooltip-short-delay
 188     tooltip-delay))
 189
 190 (defun tooltip-cancel-delayed-tip ()
 191   "Disable the tooltip timeout."
 192   (when tooltip-timeout-id
 193     (disable-timeout tooltip-timeout-id)
 194     (setq tooltip-timeout-id nil)))
 195
 196 (defun tooltip-start-delayed-tip ()
 197   "Add a one-shot timeout to call function `tooltip-timeout'."
 198   (setq tooltip-timeout-id
 199         (add-timeout (tooltip-delay) 'tooltip-timeout nil)))
 200
 201 (defun tooltip-timeout (_object)
 202   "Function called when timer with id `tooltip-timeout-id' fires."
 203   (run-hook-with-args-until-success 'tooltip-functions
 204                                     tooltip-last-mouse-motion-event))
 205
 206 \f
 207 ;;; Displaying tips
 208
 209 (defun tooltip-set-param (alist key value)
 210   "Change the value of KEY in alist ALIST to VALUE.
 211 If there's no association for KEY in ALIST, add one, otherwise
 212 change the existing association.  Value is the resulting alist."
 213   (let ((param (assq key alist)))
 214     (if (consp param)
 215         (setcdr param value)
 216       (push (cons key value) alist))
 217     alist))
 218
 219 (declare-function x-show-tip "xfns.c"
 220                   (string &optional frame parms timeout dx dy))
 221
 222 (defun tooltip-show (text &optional use-echo-area)
 223   "Show a tooltip window displaying TEXT.
 224
 225 Text larger than `x-max-tooltip-size' is clipped.
 226
 227 If the alist in `tooltip-frame-parameters' includes `left' and `top'
 228 parameters, they determine the x and y position where the tooltip
 229 is displayed.  Otherwise, the tooltip pops at offsets specified by
 230 `tooltip-x-offset' and `tooltip-y-offset' from the current mouse
 231 position.
 232
 233 Optional second arg USE-ECHO-AREA non-nil means to show tooltip
 234 in echo area."
 235   (if use-echo-area
 236       (tooltip-show-help-non-mode text)
 237     (condition-case error
 238         (let ((params (copy-sequence tooltip-frame-parameters))
 239               (fg (face-attribute 'tooltip :foreground))
 240               (bg (face-attribute 'tooltip :background)))
 241           (when (stringp fg)
 242             (setq params (tooltip-set-param params 'foreground-color fg))
 243             (setq params (tooltip-set-param params 'border-color fg)))
 244           (when (stringp bg)
 245             (setq params (tooltip-set-param params 'background-color bg)))
 246           (x-show-tip (propertize text 'face 'tooltip)
 247                       (selected-frame)
 248                       params
 249                       tooltip-hide-delay
 250                       tooltip-x-offset
 251                       tooltip-y-offset))
 252       (error
 253        (message "Error while displaying tooltip: %s" error)
 254        (sit-for 1)
 255        (message "%s" text)))))
 256
 257 (declare-function x-hide-tip "xfns.c" ())
 258
 259 (defun tooltip-hide (&optional _ignored-arg)
 260   "Hide a tooltip, if one is displayed.
 261 Value is non-nil if tooltip was open."
 262   (tooltip-cancel-delayed-tip)
 263   (when (x-hide-tip)
 264     (setq tooltip-hide-time (float-time))))
 265
 266 \f
 267 ;;; Debugger-related functions
 268
 269 (defun tooltip-identifier-from-point (point)
 270   "Extract the identifier at POINT, if any.
 271 Value is nil if no identifier exists at point.  Identifier extraction
 272 is based on the current syntax table."
 273   (save-excursion
 274     (goto-char point)
 275     (let ((start (progn (skip-syntax-backward "w_") (point))))
 276       (unless (looking-at "[0-9]")
 277         (skip-syntax-forward "w_")
 278         (when (> (point) start)
 279           (buffer-substring start (point)))))))
 280
 281 (defmacro tooltip-region-active-p ()
 282   "Value is non-nil if the region should override command actions."
 283   `(use-region-p))
 284
 285 (defun tooltip-expr-to-print (event)
 286   "Return an expression that should be printed for EVENT.
 287 If a region is active and the mouse is inside the region, print
 288 the region.  Otherwise, figure out the identifier around the point
 289 where the mouse is."
 290   (with-current-buffer (tooltip-event-buffer event)
 291     (let ((point (posn-point (event-end event))))
 292       (if (tooltip-region-active-p)
 293           (when (and (<= (region-beginning) point) (<= point (region-end)))
 294             (buffer-substring (region-beginning) (region-end)))
 295         (tooltip-identifier-from-point point)))))
 296
 297 (defun tooltip-process-prompt-regexp (process)
 298   "Return regexp matching the prompt of PROCESS at the end of a string.
 299 The prompt is taken from the value of `comint-prompt-regexp' in
 300 the buffer of PROCESS."
 301   (let ((prompt-regexp (with-current-buffer (process-buffer process)
 302                          comint-prompt-regexp)))
 303     (concat "\n*"
 304             ;; Most start with `^' but the one for `sdb' cannot be easily
 305             ;; stripped.  Code the prompt for `sdb' fixed here.
 306             (if (= (aref prompt-regexp 0) ?^)
 307                 (substring prompt-regexp 1)
 308               "\\*")
 309             "$")))
 310
 311 (defun tooltip-strip-prompt (process output)
 312   "Return OUTPUT with any prompt of PROCESS stripped from its end."
 313   (save-match-data
 314     (if (string-match (tooltip-process-prompt-regexp process) output)
 315         (substring output 0 (match-beginning 0))
 316       output)))
 317
 318 \f
 319 ;;; Tooltip help.
 320
 321 (defvar tooltip-help-message nil
 322   "The last help message received via `show-help-function'.
 323 This is used by `tooltip-show-help' and
 324 `tooltip-show-help-non-mode'.")
 325
 326 (defvar tooltip-previous-message nil
 327   "The previous content of the echo area.")
 328
 329 (defun tooltip-show-help-non-mode (help)
 330   "Function installed as `show-help-function' when Tooltip mode is off.
 331 It is also called if Tooltip mode is on, for text-only displays."
 332   (when (and (not (window-minibuffer-p)) ;Don't overwrite minibuffer contents.
 333              (not cursor-in-echo-area))  ;Don't overwrite a prompt.
 334     (cond
 335      ((stringp help)
 336       (setq help (replace-regexp-in-string "\n" ", " help))
 337       (unless (or tooltip-previous-message
 338                   (string-equal help (current-message))
 339                   (and (stringp tooltip-help-message)
 340                        (string-equal tooltip-help-message
 341                                      (current-message))))
 342         (setq tooltip-previous-message (current-message)))
 343       (setq tooltip-help-message help)
 344       (let ((message-truncate-lines t)
 345             (message-log-max nil))
 346         (message "%s" help)))
 347      ((stringp tooltip-previous-message)
 348       (let ((message-log-max nil))
 349         (message "%s" tooltip-previous-message)
 350         (setq tooltip-previous-message nil)))
 351      (t
 352       (message nil)))))
 353
 354 (defun tooltip-show-help (msg)
 355   "Function installed as `show-help-function'.
 356 MSG is either a help string to display, or nil to cancel the display."
 357   (if (display-graphic-p)
 358       (let ((previous-help tooltip-help-message))
 359         (setq tooltip-help-message msg)
 360         (cond ((null msg)
 361                ;; Cancel display.  This also cancels a delayed tip, if
 362                ;; there is one.
 363                (tooltip-hide))
 364               ((equal previous-help msg)
 365                ;; Same help as before (but possibly the mouse has moved).
 366                ;; Keep what we have.
 367                )
 368               (t
 369                ;; A different help.  Remove a previous tooltip, and
 370                ;; display a new one, with some delay.
 371                (tooltip-hide)
 372                (tooltip-start-delayed-tip))))
 373     ;; On text-only displays, try `tooltip-show-help-non-mode'.
 374     (tooltip-show-help-non-mode msg)))
 375
 376 (defun tooltip-help-tips (_event)
 377   "Hook function to display a help tooltip.
 378 This is installed on the hook `tooltip-functions', which
 379 is run when the timer with id `tooltip-timeout-id' fires.
 380 Value is non-nil if this function handled the tip."
 381   (when (stringp tooltip-help-message)
 382     (tooltip-show tooltip-help-message tooltip-use-echo-area)
 383     t))
 384
 385 (provide 'tooltip)
 386
 387 ;;; tooltip.el ends here