lisp/tooltip.el

   1 ;;; tooltip.el --- show tooltip windows
   2
   3 ;; Copyright (C) 1997, 1999-2012 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 use of graphical tooltips (Tooltip mode).
  43 With a prefix argument ARG, enable Tooltip mode if ARG is
  44 positive, and disable it otherwise.  If called from Lisp, enable
  45 it if ARG is omitted or nil.
  46
  47 When Tooltip mode is enabled, Emacs displays help text in a
  48 pop-up window for buttons and menu items that you put the mouse
  49 on.  \(However, if `tooltip-use-echo-area' is non-nil, this and
  50 all pop-up help appears in the echo area.)
  51
  52 When Tooltip mode is disabled, Emacs displays one line of
  53 the help text in the echo area, and does not make a pop-up window."
  54   :global t
  55   ;; Even if we start on a text-only terminal, make this non-nil by
  56   ;; default because we can open a graphical frame later (multi-tty).
  57   :init-value t
  58   :initialize 'custom-initialize-delay
  59   :group 'tooltip
  60   (unless (or (null tooltip-mode) (fboundp 'x-show-tip))
  61     (error "Sorry, tooltips are not yet available on this system"))
  62   (if tooltip-mode
  63       (progn
  64         (add-hook 'pre-command-hook 'tooltip-hide)
  65         (add-hook 'tooltip-functions 'tooltip-help-tips))
  66     (unless (and (boundp 'gud-tooltip-mode) gud-tooltip-mode)
  67       (remove-hook 'pre-command-hook 'tooltip-hide))
  68     (remove-hook 'tooltip-functions 'tooltip-help-tips))
  69   (setq show-help-function
  70         (if tooltip-mode 'tooltip-show-help 'tooltip-show-help-non-mode)))
  71
  72 \f
  73 ;;; Customizable settings
  74
  75 (defcustom tooltip-delay 0.7
  76   "Seconds to wait before displaying a tooltip the first time."
  77   :type 'number
  78   :group 'tooltip)
  79
  80 (defcustom tooltip-short-delay 0.1
  81   "Seconds to wait between subsequent tooltips on different items."
  82   :type 'number
  83   :group 'tooltip)
  84
  85 (defcustom tooltip-recent-seconds 1
  86   "Display tooltips if changing tip items within this many seconds.
  87 Do so after `tooltip-short-delay'."
  88   :type 'number
  89   :group 'tooltip)
  90
  91 (defcustom tooltip-hide-delay 10
  92   "Hide tooltips automatically after this many seconds."
  93   :type 'number
  94   :group 'tooltip)
  95
  96 (defcustom tooltip-x-offset 5
  97   "X offset, in pixels, for the display of tooltips.
  98 The offset is the distance between the X position of the mouse and
  99 the left border of the tooltip window.  It must be chosen so that the
 100 tooltip window doesn't contain the mouse when it pops up, or it may
 101 interfere with clicking where you wish.
 102
 103 If `tooltip-frame-parameters' includes the `left' parameter,
 104 the value of `tooltip-x-offset' is ignored."
 105   :type 'integer
 106   :group 'tooltip)
 107
 108 (defcustom tooltip-y-offset +20
 109   "Y offset, in pixels, for the display of tooltips.
 110 The offset is the distance between the Y position of the mouse and
 111 the top border of the tooltip window.  It must be chosen so that the
 112 tooltip window doesn't contain the mouse when it pops up, or it may
 113 interfere with clicking where you wish.
 114
 115 If `tooltip-frame-parameters' includes the `top' parameter,
 116 the value of `tooltip-y-offset' is ignored."
 117   :type 'integer
 118   :group 'tooltip)
 119
 120 (defcustom tooltip-frame-parameters
 121   '((name . "tooltip")
 122     (internal-border-width . 2)
 123     (border-width . 1))
 124   "Frame parameters used for tooltips.
 125
 126 If `left' or `top' parameters are included, they specify the absolute
 127 position to pop up the tooltip.
 128
 129 Note that font and color parameters are ignored, and the attributes
 130 of the `tooltip' face are used instead."
 131   :type 'sexp
 132   :group 'tooltip)
 133
 134 (defface tooltip
 135   '((((class color))
 136      :background "lightyellow"
 137      :foreground "black"
 138      :inherit variable-pitch)
 139     (t
 140      :inherit variable-pitch))
 141   "Face for tooltips."
 142   :group 'tooltip
 143   :group 'basic-faces)
 144
 145 (defcustom tooltip-use-echo-area nil
 146   "Use the echo area instead of tooltip frames for help and GUD tooltips.
 147 To display multi-line help text in the echo area, set this to t
 148 and enable `tooltip-mode'."
 149   :type 'boolean
 150   :group 'tooltip)
 151
 152 \f
 153 ;;; Variables that are not customizable.
 154
 155 (defvar tooltip-functions nil
 156   "Functions to call to display tooltips.
 157 Each function is called with one argument EVENT which is a copy
 158 of the last mouse movement event that occurred.  If one of these
 159 functions displays the tooltip, it should return non-nil and the
 160 rest are not called.")
 161
 162 (define-obsolete-variable-alias 'tooltip-hook 'tooltip-functions "23.1")
 163
 164 (defvar tooltip-timeout-id nil
 165   "The id of the timeout started when Emacs becomes idle.")
 166
 167 (defvar tooltip-last-mouse-motion-event nil
 168   "A copy of the last mouse motion event seen.")
 169
 170 (defvar tooltip-hide-time nil
 171   "Time when the last tooltip was hidden.")
 172
 173 (defvar gud-tooltip-mode) ;; Prevent warning.
 174
 175 ;;; Event accessors
 176
 177 (defun tooltip-event-buffer (event)
 178   "Return the buffer over which event EVENT occurred.
 179 This might return nil if the event did not occur over a buffer."
 180   (let ((window (posn-window (event-end event))))
 181     (and window (window-buffer window))))
 182
 183 \f
 184 ;;; Timeout for tooltip display
 185
 186 (defun tooltip-delay ()
 187   "Return the delay in seconds for the next tooltip."
 188   (if (and tooltip-hide-time
 189            (< (- (float-time) tooltip-hide-time) tooltip-recent-seconds))
 190       tooltip-short-delay
 191     tooltip-delay))
 192
 193 (defun tooltip-cancel-delayed-tip ()
 194   "Disable the tooltip timeout."
 195   (when tooltip-timeout-id
 196     (disable-timeout tooltip-timeout-id)
 197     (setq tooltip-timeout-id nil)))
 198
 199 (defun tooltip-start-delayed-tip ()
 200   "Add a one-shot timeout to call function `tooltip-timeout'."
 201   (setq tooltip-timeout-id
 202         (add-timeout (tooltip-delay) 'tooltip-timeout nil)))
 203
 204 (defun tooltip-timeout (_object)
 205   "Function called when timer with id `tooltip-timeout-id' fires."
 206   (run-hook-with-args-until-success 'tooltip-functions
 207                                     tooltip-last-mouse-motion-event))
 208
 209 \f
 210 ;;; Displaying tips
 211
 212 (defun tooltip-set-param (alist key value)
 213   "Change the value of KEY in alist ALIST to VALUE.
 214 If there's no association for KEY in ALIST, add one, otherwise
 215 change the existing association.  Value is the resulting alist."
 216   (let ((param (assq key alist)))
 217     (if (consp param)
 218         (setcdr param value)
 219       (push (cons key value) alist))
 220     alist))
 221
 222 (declare-function x-show-tip "xfns.c"
 223                   (string &optional frame parms timeout dx dy))
 224
 225 (defun tooltip-show (text &optional use-echo-area)
 226   "Show a tooltip window displaying TEXT.
 227
 228 Text larger than `x-max-tooltip-size' is clipped.
 229
 230 If the alist in `tooltip-frame-parameters' includes `left' and `top'
 231 parameters, they determine the x and y position where the tooltip
 232 is displayed.  Otherwise, the tooltip pops at offsets specified by
 233 `tooltip-x-offset' and `tooltip-y-offset' from the current mouse
 234 position.
 235
 236 Optional second arg USE-ECHO-AREA non-nil means to show tooltip
 237 in echo area."
 238   (if use-echo-area
 239       (tooltip-show-help-non-mode text)
 240     (condition-case error
 241         (let ((params (copy-sequence tooltip-frame-parameters))
 242               (fg (face-attribute 'tooltip :foreground))
 243               (bg (face-attribute 'tooltip :background)))
 244           (when (stringp fg)
 245             (setq params (tooltip-set-param params 'foreground-color fg))
 246             (setq params (tooltip-set-param params 'border-color fg)))
 247           (when (stringp bg)
 248             (setq params (tooltip-set-param params 'background-color bg)))
 249           (x-show-tip (propertize text 'face 'tooltip)
 250                       (selected-frame)
 251                       params
 252                       tooltip-hide-delay
 253                       tooltip-x-offset
 254                       tooltip-y-offset))
 255       (error
 256        (message "Error while displaying tooltip: %s" error)
 257        (sit-for 1)
 258        (message "%s" text)))))
 259
 260 (declare-function x-hide-tip "xfns.c" ())
 261
 262 (defun tooltip-hide (&optional _ignored-arg)
 263   "Hide a tooltip, if one is displayed.
 264 Value is non-nil if tooltip was open."
 265   (tooltip-cancel-delayed-tip)
 266   (when (x-hide-tip)
 267     (setq tooltip-hide-time (float-time))))
 268
 269 \f
 270 ;;; Debugger-related functions
 271
 272 (defun tooltip-identifier-from-point (point)
 273   "Extract the identifier at POINT, if any.
 274 Value is nil if no identifier exists at point.  Identifier extraction
 275 is based on the current syntax table."
 276   (save-excursion
 277     (goto-char point)
 278     (let ((start (progn (skip-syntax-backward "w_") (point))))
 279       (unless (looking-at "[0-9]")
 280         (skip-syntax-forward "w_")
 281         (when (> (point) start)
 282           (buffer-substring start (point)))))))
 283
 284 (defmacro tooltip-region-active-p ()
 285   "Value is non-nil if the region should override command actions."
 286   `(use-region-p))
 287
 288 (defun tooltip-expr-to-print (event)
 289   "Return an expression that should be printed for EVENT.
 290 If a region is active and the mouse is inside the region, print
 291 the region.  Otherwise, figure out the identifier around the point
 292 where the mouse is."
 293   (with-current-buffer (tooltip-event-buffer event)
 294     (let ((point (posn-point (event-end event))))
 295       (if (tooltip-region-active-p)
 296           (when (and (<= (region-beginning) point) (<= point (region-end)))
 297             (buffer-substring (region-beginning) (region-end)))
 298         (tooltip-identifier-from-point point)))))
 299
 300 (defun tooltip-process-prompt-regexp (process)
 301   "Return regexp matching the prompt of PROCESS at the end of a string.
 302 The prompt is taken from the value of `comint-prompt-regexp' in
 303 the buffer of PROCESS."
 304   (let ((prompt-regexp (with-current-buffer (process-buffer process)
 305                          comint-prompt-regexp)))
 306     (concat "\n*"
 307             ;; Most start with `^' but the one for `sdb' cannot be easily
 308             ;; stripped.  Code the prompt for `sdb' fixed here.
 309             (if (= (aref prompt-regexp 0) ?^)
 310                 (substring prompt-regexp 1)
 311               "\\*")
 312             "$")))
 313
 314 (defun tooltip-strip-prompt (process output)
 315   "Return OUTPUT with any prompt of PROCESS stripped from its end."
 316   (save-match-data
 317     (if (string-match (tooltip-process-prompt-regexp process) output)
 318         (substring output 0 (match-beginning 0))
 319       output)))
 320
 321 \f
 322 ;;; Tooltip help.
 323
 324 (defvar tooltip-help-message nil
 325   "The last help message received via `show-help-function'.
 326 This is used by `tooltip-show-help' and
 327 `tooltip-show-help-non-mode'.")
 328
 329 (defvar tooltip-previous-message nil
 330   "The previous content of the echo area.")
 331
 332 (defun tooltip-show-help-non-mode (help)
 333   "Function installed as `show-help-function' when Tooltip mode is off.
 334 It is also called if Tooltip mode is on, for text-only displays."
 335   (when (and (not (window-minibuffer-p)) ;Don't overwrite minibuffer contents.
 336              (not cursor-in-echo-area))  ;Don't overwrite a prompt.
 337     (cond
 338      ((stringp help)
 339       (setq help (replace-regexp-in-string "\n" ", " help))
 340       (unless (or tooltip-previous-message
 341                   (string-equal help (current-message))
 342                   (and (stringp tooltip-help-message)
 343                        (string-equal tooltip-help-message
 344                                      (current-message))))
 345         (setq tooltip-previous-message (current-message)))
 346       (setq tooltip-help-message help)
 347       (let ((message-truncate-lines t)
 348             (message-log-max nil))
 349         (message "%s" help)))
 350      ((stringp tooltip-previous-message)
 351       (let ((message-log-max nil))
 352         (message "%s" tooltip-previous-message)
 353         (setq tooltip-previous-message nil)))
 354      (t
 355       (message nil)))))
 356
 357 (defun tooltip-show-help (msg)
 358   "Function installed as `show-help-function'.
 359 MSG is either a help string to display, or nil to cancel the display."
 360   (if (display-graphic-p)
 361       (let ((previous-help tooltip-help-message))
 362         (setq tooltip-help-message msg)
 363         (cond ((null msg)
 364                ;; Cancel display.  This also cancels a delayed tip, if
 365                ;; there is one.
 366                (tooltip-hide))
 367               ((equal previous-help msg)
 368                ;; Same help as before (but possibly the mouse has moved).
 369                ;; Keep what we have.
 370                )
 371               (t
 372                ;; A different help.  Remove a previous tooltip, and
 373                ;; display a new one, with some delay.
 374                (tooltip-hide)
 375                (tooltip-start-delayed-tip))))
 376     ;; On text-only displays, try `tooltip-show-help-non-mode'.
 377     (tooltip-show-help-non-mode msg)))
 378
 379 (defun tooltip-help-tips (_event)
 380   "Hook function to display a help tooltip.
 381 This is installed on the hook `tooltip-functions', which
 382 is run when the timer with id `tooltip-timeout-id' fires.
 383 Value is non-nil if this function handled the tip."
 384   (when (stringp tooltip-help-message)
 385     (tooltip-show tooltip-help-message tooltip-use-echo-area)
 386     t))
 387
 388 (provide 'tooltip)
 389
 390 ;;; tooltip.el ends here