lisp/mouse-copy.el

   1 ;;; mouse-copy.el --- one-click text copy and move
   2
   3 ;; Copyright (C) 1996, 2001-2018 Free Software Foundation, Inc.
   4
   5 ;; Author: John Heidemann <johnh@ISI.EDU>
   6 ;; Keywords: mouse
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software: you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation, either version 3 of the License, or
  13 ;; (at your option) any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;; What is ``mouse-copy.el''?
  26 ;;
  27 ;; It provides one-click text copy and move.  Rather than the
  28 ;; standard stroke-out-a-region (down-mouse-1, up-mouse-1) followed
  29 ;; by a yank (down-mouse-2, up-mouse-2 or C-y), you can now stroke
  30 ;; out a region and have it automatically pasted at the current
  31 ;; point.  You can also move text just as easily.  Although the
  32 ;; difference may not sound like much, it does make mousing text
  33 ;; around a lot easier, IMHO.
  34 ;;
  35 ;; If you like mouse-copy, you should also check out mouse-drag
  36 ;; for ``one-click scrolling''.
  37 ;;
  38 ;; To use mouse-copy, place the following in your init file:
  39 ;;      (require 'mouse-copy)
  40 ;;     (global-set-key [M-down-mouse-1] 'mouse-drag-secondary-pasting)
  41 ;;     (global-set-key [M-S-down-mouse-1] 'mouse-drag-secondary-moving)
  42 ;;
  43 ;; (These definitions override the old binding of M-mouse-1 to
  44 ;; mouse-drag-secondary.  I find I don't use that command much so its
  45 ;; loss is not important, and it can be made up with a M-mouse-1
  46 ;; followed by a M-mouse-3.  I personally reserve M-mouse bindings
  47 ;; for my window manager and bind everything to C-mouse.)
  48 ;;
  49 ;;
  50 ;; History and related work:
  51 ;;
  52 ;; One-click copying and moving was inspired by lemacs-19.8.
  53 ;; Throw-scrolling was inspired by MacPaint's ``hand'' and by Tk's
  54 ;; mouse-2 scrolling.  The package mouse-scroll.el by Tom Wurgler
  55 ;; <twurgler@goodyear.com> is similar to mouse-drag-throw, but
  56 ;; doesn't pass clicks through.
  57 ;;
  58 ;; These functions have been tested in emacs version 19.30,
  59 ;; and this package has run in the past on 19.25-19.29.
  60 ;;
  61 ;; Originally mouse-copy was part of a larger package.
  62 ;; As of 11 July 96 the scrolling functions were split out
  63 ;; in preparation for incorporation into (the future) emacs-19.32.
  64 ;;
  65 ;;
  66 ;; Known Bugs:
  67 ;;
  68 ;; - Highlighting is sub-optimal under 19.29 and XFree86-3.1.1
  69 ;;   (see \\[mouse-copy-work-around-drag-bug] for details).
  70 ;; - mouse-drag-secondary-pasting and mouse-drag-secondary-moving
  71 ;;   require X11R5 (or better) and so fail under older versions
  72 ;;   of Open Windows (like that present in Solaris/x86 2.1).
  73 ;;
  74 ;;
  75 ;; Future plans:
  76 ;;
  77 ;; I read about the chording features of Plan-9's Acme environment at
  78 ;; <http://www.zip.com.au/~cs/app/wily/auug.html>.  I'd like
  79 ;; to incorporate some of these ideas into mouse-copy.  The only
  80 ;; lose is that this is not the current Emacs Way Of Doing Things, so
  81 ;; there would be a learning curve for existing emacs users.
  82 ;;
  83 ;;
  84 ;; Thanks:
  85 ;;
  86 ;; Thanks to Kai Grossjohann
  87 ;; <grossjoh@dusty.informatik.uni-dortmund.de> for reporting bugs, to
  88 ;; Tom Wurgler <twurgler@goodyear.com> for reporting bugs and
  89 ;; suggesting fixes, and to Joel Graber <jgraber@ti.com> for
  90 ;; prompting me to do drag-scrolling and for an initial
  91 ;; implementation of horizontal drag-scrolling.
  92 ;;
  93 ;;    -johnh, 11-Jul-96
  94 \f
  95 ;;; Code:
  96
  97 ;;
  98 ;; move/paste code
  99 ;;
 100
 101 (defvar mouse-copy-last-paste-start nil
 102   "Internal to `mouse-drag-secondary-pasting'.")
 103 (defvar mouse-copy-last-paste-end nil
 104   "Internal to `mouse-drag-secondary-pasting'.")
 105
 106 (defvar mouse-copy-have-drag-bug nil
 107   "Set to enable mouse-copy-work-around-drag-bug.
 108 See `mouse-copy-work-around-drag-bug' for details.")
 109
 110 (defun mouse-copy-work-around-drag-bug (start-event end-event)
 111   "Code to work around a bug in post-19.29 Emacs: it drops mouse-drag events.
 112 The problem occurs under XFree86-3.1.1 (X11R6pl11) but not under X11R5,
 113 and under post-19.29 but not early versions of Emacs.
 114
 115 19.29 and 19.30 seems to drop mouse drag events
 116 sometimes. (Reproducible under XFree86-3.1.1 (X11R6pl11) and
 117 XFree86-3.1.2 under Linux 1.2.x.  Doesn't occur under X11R5 and SunOS
 118 4.1.1.)
 119
 120 To see if you have the problem:
 121 Disable this routine (with (setq mouse-copy-have-drag-bug nil)).
 122 Click and drag for a while.
 123 If highlighting stops tracking, you have the bug.
 124 If you have the bug (or the real fix :-), please let me know."
 125
 126   ;; To work-around, call mouse-set-secondary with a fake
 127   ;; drag event to set the overlay,
 128   ;; the load the x-selection.
 129   (save-excursion
 130     (let*
 131         ((start-posn (event-start start-event))
 132          (end-posn (event-end end-event))
 133          (end-buffer (window-buffer (posn-window end-posn)))
 134          ;; First, figure out the region (left as point/mark).
 135          (range (progn
 136                   (set-buffer end-buffer)
 137                   (mouse-start-end (posn-point start-posn)
 138                                  (posn-point end-posn)
 139                                  (1- (event-click-count start-event)))))
 140          (beg (car range))
 141          (end (car (cdr range))))
 142       ;; Second, set the overlay.
 143       (if mouse-secondary-overlay
 144           (move-overlay mouse-secondary-overlay beg end)
 145         (setq mouse-secondary-overlay (make-overlay beg (posn-point end))))
 146       (overlay-put mouse-secondary-overlay 'face 'secondary-selection)
 147       ;; Third, set the selection.
 148       ;; (setq me-beg beg me-end end me-range range)  ; for debugging
 149       (set-buffer end-buffer)
 150       (gui-set-selection 'SECONDARY (buffer-substring beg end)))))
 151
 152
 153 (defun mouse-drag-secondary-pasting (start-event)
 154   "Drag out a secondary selection, then paste it at the current point.
 155
 156 To test this function, evaluate:
 157         (global-set-key [M-down-mouse-1] \\='mouse-drag-secondary-pasting)
 158 put the point at one place, then click and drag over some other region."
 159   (interactive "e")
 160   ;; Work-around: We see and react to each part of a multi-click event
 161   ;; as it proceeds.  For a triple-event, this means the double-event
 162   ;; has already copied something that the triple-event will re-copy
 163   ;; (a Bad Thing).  We therefore undo the prior insertion if we're on
 164   ;; a multiple event.
 165   (if (and mouse-copy-last-paste-start
 166            (>= (event-click-count start-event) 2))
 167       (delete-region mouse-copy-last-paste-start
 168                      mouse-copy-last-paste-end))
 169
 170   ;; HACK: We assume that mouse-drag-secondary returns nil if
 171   ;; there's no secondary selection.  This assumption holds as of
 172   ;; emacs-19.22 but is not documented.  It's not clear that there's
 173   ;; any other way to get this information.
 174   (if (mouse-drag-secondary start-event)
 175       (progn
 176         (if mouse-copy-have-drag-bug
 177             (mouse-copy-work-around-drag-bug start-event last-input-event))
 178         ;; Remember what we do so we can undo it, if necessary.
 179         (setq mouse-copy-last-paste-start (point))
 180         (insert (gui-get-selection 'SECONDARY))
 181         (setq mouse-copy-last-paste-end (point)))
 182     (setq mouse-copy-last-paste-start nil)))
 183
 184
 185 (defun mouse-kill-preserving-secondary ()
 186   "Kill the text in the secondary selection, but leave the selection set.
 187
 188 This command is like \\[mouse-kill-secondary] (that is, the secondary
 189 selection is deleted and placed in the kill ring), except that it also
 190 leaves the secondary buffer active on exit.
 191
 192 This command was derived from mouse-kill-secondary in emacs-19.28
 193 by johnh@ficus.cs.ucla.edu."
 194   (interactive)
 195   (let* ((keys (this-command-keys))
 196          (click (elt keys (1- (length keys)))))
 197     (or (eq (overlay-buffer mouse-secondary-overlay)
 198             (if (listp click)
 199                 (window-buffer (posn-window (event-start click)))
 200               (current-buffer)))
 201         (error "Select or click on the buffer where the secondary selection is")))
 202   (with-current-buffer (overlay-buffer mouse-secondary-overlay)
 203     (kill-region (overlay-start mouse-secondary-overlay)
 204                  (overlay-end mouse-secondary-overlay)))
 205   ;; (delete-overlay mouse-secondary-overlay)
 206   ;; (gui-set-selection 'SECONDARY nil)
 207   ;; (setq mouse-secondary-overlay nil)
 208 )
 209
 210 (defun mouse-drag-secondary-moving (start-event)
 211   "Sweep out a secondary selection, then move it to the current point."
 212   (interactive "e")
 213   ;; HACK:  We assume that mouse-drag-secondary returns nil if
 214   ;; there's no secondary selection.  This works as of emacs-19.22.
 215   ;; It's not clear that there's any other way to get this information.
 216   (if (mouse-drag-secondary start-event)
 217       (progn
 218         (mouse-kill-preserving-secondary)
 219         (insert (gui-get-selection 'SECONDARY))))
 220 )
 221
 222 (provide 'mouse-copy)
 223
 224 ;;; mouse-copy.el ends here