mouse.el patch to flash yank position and highlight line

mouse.el patch to flash yank position and highlight line

[Drew Adams]

The mouse.el patch below adds a couple commands:

* `mouse-flash-position' highlights the character under the mouse pointer.

* `mouse-scan-lines' highlights the line at the mouse position.

This highlighting remains, even as you drag. These are to be bound to mouse
`down' events; the end of dragging (at the `up' event) removes the
highlighting.

The idea behind `mouse-flash-position' is to help make it clear exactly
where a `yank' will occur when you use `mouse-2'.  When you press `mouse-2'
(i.e. `down-mouse-2'), if the highlighted position is not exactly what you
want, just keep `mouse-2' held while you move to the right location. The
yank is bound to `mouse-2' (the up event), so the only difference you see is
a brief indication of the position, while the button is depressed.

The idea behind `mouse-scan-lines' is to help you visually align entries
that are in the same row (line), in buffers such as Dired that use tabular
data (tables with columns). Just hold Shift with `mouse-2' and drag over
table rows - the row under the mouse stays highlighted. This needs nothing
built into the buffer (e.g. Dired); it is always available.

There are versions of these commands that have enhanced behavior in the echo
area, where yanking is impossible anyway:

* `mouse-flash-position-or-M-x' - `mouse-flash-position', except same as
`M-x' if in echo area.

*  `mouse-scan-lines-or-M-:' - `mouse-scan-lines', except same as `M-:' if
in echo area.

This means that you can click `mouse-2' in the echo area to get the `M-x'
prompt, and `S-mouse-2' to get the `M-:' prompt. This does not interfere
with standard behavior, because the echo area is read-only (currently,
`mouse-2' there just says that the minibuffer is not active).

The patch also makes these changes:

* A fix to `mouse-yank-secondary', so you get a reasonable error message if
the secondary selection is not yet defined (instead of "Wrong type argument:
char-or-string-p, nil").

* `mouse-tear-off-window' does not try to delete the window if it is the
only one in its frame. Instead, it clones the frame and window. That is, it
does a "tear-off" at the frame level, instead of the window level.

If others agree about this patch, then I'll send NEWS and Change log
updates.

If we agree about the patch, then there's also the question of bindings.
Users could make the following bindings themselves, but I propose that we
make these the default bindings:

* `down-mouse-2' - `mouse-flash-position-or-M-x'
* `S-down-mouse-2' - `mouse-scan-lines-or-M-:'

These would be in addition to the standard `mouse-2' binding for yanking.
WDOT?

You can see more description of these enhancements here:
http://www.emacswiki.org/cgi-bin/wiki/MousePlus.

------------8<------------------------------------

*** mouse-CVS-2007-07-13.el	Fri Jul 13 14:49:54 2007
--- mouse-CVS-patched-2007-07-13.el	Fri Jul 13 15:19:50 2007
***************
*** 38,43 ****
--- 38,71 ----
  ;;; Indent track-mouse like progn.
  (put 'track-mouse 'lisp-indent-function 0)

+ (defface mouse-scan-lines '((t (:background "Yellow")))
+   "*Face used to temporarily highlight line at mouse position."
+   :group 'mouse)
+
+ (defface mouse-flash-position '((t (:background "Yellow")))
+   "*Face used to highlight mouse position temporarily."
+   :group 'mouse)
+
+ (defconst mouse-scan-lines-overlay
+     ;; Create and immediately delete, to get "overlay in no buffer".
+     (let ((ol (make-overlay (point-min) (point-min))))
+       (delete-overlay ol)
+       (overlay-put ol 'face       'mouse-scan-lines)
+       (overlay-put ol 'mouse-face 'mouse-scan-lines)
+       (overlay-put ol 'priority   1000000)
+       ol)
+   "Overlay to highlight line at mouse position.")
+
+ (defconst mouse-flash-posn-overlay
+     ;; Create and immediately delete, to get "overlay in no buffer".
+   (let ((ol (make-overlay (point-min) (point-min))))
+     (delete-overlay ol)
+     (overlay-put ol 'face 'mouse-flash-position)
+     (overlay-put ol 'mouse-face 'mouse-flash-position)
+     (overlay-put ol 'priority 1000000)
+     ol)
+   "Overlay to highlight current mouse position.")
+
  (defcustom mouse-yank-at-point nil
    "*If non-nil, mouse yank commands yank at point instead of at click."
    :type 'boolean
***************
*** 305,311 ****
  	(set-mouse-position (selected-frame) (1- (frame-width)) 0))))

  (defun mouse-tear-off-window (click)
!   "Delete the window clicked on, and create a new frame displaying its
buffer."
    (interactive "e")
    (mouse-minibuffer-check click)
    (let* ((window (posn-window (event-start click)))
--- 333,341 ----
  	(set-mouse-position (selected-frame) (1- (frame-width)) 0))))

  (defun mouse-tear-off-window (click)
!   "Create a new frame displaying buffer of clicked window.
! If window is not the only one in frame, then delete it.
! Otherwise, this command effectively clones the frame and window."
    (interactive "e")
    (mouse-minibuffer-check click)
    (let* ((window (posn-window (event-start click)))
***************
*** 313,319 ****
  	 (frame (make-frame)))
      (select-frame frame)
      (switch-to-buffer buf)
!     (delete-window window)))

  (defun mouse-delete-other-windows ()
    "Delete all windows except the one you click on."
--- 343,350 ----
  	 (frame (make-frame)))
      (select-frame frame)
      (switch-to-buffer buf)
!     (save-window-excursion (select-window window)
!                            (unless (one-window-p) (delete-window
window)))))

  (defun mouse-delete-other-windows ()
    "Delete all windows except the one you click on."
***************
*** 1631,1637 ****
    ;; Give temporary modes such as isearch a chance to turn off.
    (run-hooks 'mouse-leave-buffer-hook)
    (or mouse-yank-at-point (mouse-set-point click))
!   (insert (x-get-selection 'SECONDARY)))

  (defun mouse-kill-secondary ()
    "Kill the text in the secondary selection.
--- 1662,1671 ----
    ;; Give temporary modes such as isearch a chance to turn off.
    (run-hooks 'mouse-leave-buffer-hook)
    (or mouse-yank-at-point (mouse-set-point click))
!   (let ((secondary (x-get-selection 'SECONDARY)))
!     (if secondary
!         (insert (x-get-selection 'SECONDARY))
!       (error "No secondary selection"))))

  (defun mouse-kill-secondary ()
    "Kill the text in the secondary selection.
***************
*** 2424,2429 ****
--- 2458,2640 ----
  	(if (null font)
  	    (error "Font not found")))))
  \f
+ (defun mouse-scan-lines-or-M-: (start-event)
+   "In echo area, `M-:'.  Else, highlight current line, tracking pointer."
+   (interactive "e")
+   (let ((win (posn-window (event-start start-event)))
+         (bufs (buffer-list))
+         (M-:-cmd (key-binding "\M-:" t)))
+     (cond ((and (window-minibuffer-p win) (not (minibuffer-window-active-p
win)) M-:-cmd)
+            (read-event)                 ; Ignore mouse up event.
+            (while (string-match "\\` \\*Minibuf-[0-9]+\\*\\'" (buffer-name
(car bufs)))
+              (pop bufs))
+            (when bufs (set-buffer (car bufs)))
+            (switch-to-buffer-other-window (current-buffer))
+            (call-interactively M-:-cmd nil [(meta ?:)]))
+           (t
+            (mouse-scan-lines start-event)))))
+
+ (defun mouse-M-: (start-event)
+   "In the echo area, do `M-:'.  Otherwise, do nothing."
+   (interactive "e")
+   (let ((win (posn-window (event-start start-event)))
+         (bufs (buffer-list))
+         (M-:-cmd (key-binding "\M-:" t)))
+     (cond ((and (window-minibuffer-p win) (not (minibuffer-window-active-p
win)) M-:-cmd)
+            (read-event)                 ; Ignore mouse up event.
+            (while (string-match "\\` \\*Minibuf-[0-9]+\\*\\'" (buffer-name
(car bufs)))
+              (pop bufs))
+            (when bufs (set-buffer (car bufs)))
+            (switch-to-buffer-other-window (current-buffer))
+            (call-interactively M-:-cmd nil [(meta ?:)]))
+           (t
+            (run-hooks 'mouse-leave-buffer-hook))))) ; Let temp modes like
isearch turn off.
+
+ (defun mouse-scan-lines (start-event)
+   "Track mouse drags, highlighting the line under the pointer."
+   (interactive "e")
+   (save-excursion
+     (run-hooks 'mouse-leave-buffer-hook) ; Let temporary modes like
isearch turn off.
+     (let* ((original-window (selected-window))
+            (echo-keystrokes 0)
+            (start-posn (event-start start-event))
+            (start-point (posn-point start-posn))
+            (start-window (posn-window start-posn)))
+       (move-overlay mouse-scan-lines-overlay
+                     (save-excursion (goto-char start-point)
(beginning-of-line) (point))
+                     (save-excursion (goto-char start-point) (end-of-line)
(point)))
+       (let (event end end-point)
+         (track-mouse
+           (while (progn (setq event (read-event))
+                         (or (mouse-movement-p event)
+                             (memq (car-safe event) '(switch-frame
select-window))))
+             (unless (memq (car-safe event) '(switch-frame select-window))
+               (setq end (event-end event) end-point (posn-point end))
+               (when (and (eq (posn-window end) start-window)
(integer-or-marker-p end-point))
+                 (move-overlay
+                  mouse-scan-lines-overlay
+                  (save-excursion (goto-char end-point) (beginning-of-line)
(point))
+                  (save-excursion (goto-char end-point) (end-of-line)
(point)))))))
+         (delete-overlay mouse-scan-lines-overlay)))))
+
+ (defun mouse-move-flash-posn-overlay (ol start end)
+   "Move `mouse-flash-posn-overlay' to position END.
+ START is the position of the start of the current drag operation."
+   (unless (= start end)
+     ;; Go to START first, so that when we move to END, if it's in the
middle
+     ;; of intangible text, point jumps in the direction away from START.
+     ;; Don't do it if START=END, otherwise a single click risks selecting
+     ;; a region if it's on intangible text.  This exception was originally
+     ;; only applied on entry to mouse-drag-region, which had the problem
+     ;; that a tiny move during a single-click would cause the intangible
+     ;; text to be selected.
+     (goto-char start)
+     (goto-char end)
+     (setq end (point)))
+   (move-overlay ol end (min (point-max) (1+ end))))
+
+ (defun mouse-flash-position-or-M-x (start-event)
+   "In the echo area, do `M-x'.  Otherwise, do `mouse-flash-position'."
+   (interactive "e")
+   (let ((win (posn-window (event-start start-event)))
+         (bufs (buffer-list))
+         (M-x-cmd (key-binding "\M-x" t)))
+     (cond ((and (window-minibuffer-p win) (not (minibuffer-window-active-p
win)) M-x-cmd)
+            (read-event)                 ; Ignore mouse up event.
+            (while (string-match "\\` \\*Minibuf-[0-9]+\\*\\'" (buffer-name
(car bufs)))
+              (pop bufs))
+            (when bufs (set-buffer (car bufs)))
+            (switch-to-buffer-other-window (current-buffer))
+            (call-interactively M-x-cmd nil [(meta ?x)]))
+           (t
+            (run-hooks 'mouse-leave-buffer-hook) ; Let temporary modes like
isearch turn off.
+            (mouse-flash-posn-track start-event)))))
+
+ (defun mouse-flash-position (start-event)
+   "Highlight the mouse position as you drag the mouse.
+ This must be bound to a button-down mouse event.  If you bind this to
+ `down-mouse-2', and `mouse-2' is bound to `mouse-yank-at-click' (the
+ default), then the yank occurs just before the highlighted character.
+
+ If you want to prevent the `mouse-2' up-button yank from taking place,
+ perhaps because you changed your mind, you can press and hold `C-g'
+ while releasing the mouse button (press `mouse-2'; drag; press `C-g';
+ release `mouse-2'; release `C-g')."
+   (interactive "e")
+   (run-hooks 'mouse-leave-buffer-hook)  ; Let temporary modes such as
isearch turn off.
+   (mouse-flash-posn-track start-event))
+
+ (defun mouse-flash-posn-track (start-event)
+   "Track mouse drags by highlighting the mouse position"
+   (mouse-minibuffer-check start-event)
+   (let* ((original-window (selected-window))
+          (echo-keystrokes 0)
+ 	 (start-posn (event-start start-event))
+ 	 (start-point (posn-point start-posn))
+ 	 (start-window (posn-window start-posn))
+ 	 (start-window-start (window-start start-window))
+ 	 (start-hscroll (window-hscroll start-window))
+ 	 (bounds (window-edges start-window))
+ 	 (make-cursor-line-fully-visible nil)
+ 	 (top (nth 1 bounds))
+ 	 (bottom (if (window-minibuffer-p start-window)
+ 		     (nth 3 bounds)
+ 		   (1- (nth 3 bounds))))) ; 1-: Don't count the mode line.
+     (mouse-move-flash-posn-overlay mouse-flash-posn-overlay start-point
start-point)
+     (overlay-put mouse-flash-posn-overlay 'window start-window)
+     (deactivate-mark)
+     (unwind-protect
+          (let (event end end-point last-end-point)
+            (track-mouse
+              (while (progn (setq event (read-event))
+                            (or (mouse-movement-p event)
+                                (memq (car-safe event) '(switch-frame
select-window))))
+                (unless (memq (car-safe event) '(switch-frame
select-window))
+                  (setq end (event-end event)
+                        end-point (posn-point end))
+                  (when (numberp end-point) (setq last-end-point
end-point))
+                  (cond
+                    ((and (eq (posn-window end) start-window) ; Moving
within original window.
+                          (integer-or-marker-p end-point))
+                     (mouse-move-flash-posn-overlay
mouse-flash-posn-overlay
+                                                    start-point end-point))
+                    (t
+                     (let ((mouse-row (cddr (mouse-position))))
+                       (cond
+                         ((null mouse-row))
+                         ((< mouse-row top)
+                          (mouse-scroll-subr start-window (- mouse-row top)
+                                             mouse-flash-posn-overlay
start-point))
+                         ((>= mouse-row bottom)
+                          (mouse-scroll-subr start-window (1+ (- mouse-row
bottom))
+                                             mouse-flash-posn-overlay
start-point)))))))))
+            ;; In case we did not get a mouse-motion event for the final
move of
+            ;; the mouse before a drag event, pretend that we did get one.
+            (when (and (memq 'drag (event-modifiers (car-safe event)))
+                       (setq end (event-end event)  end-point (posn-point
end))
+                       (eq (posn-window end) start-window)
+                       (integer-or-marker-p end-point))
+              (mouse-move-flash-posn-overlay mouse-flash-posn-overlay
start-point end-point))
+            (when (consp event)          ; Handle the terminating event.
+              (let ((fun (key-binding (vector (car event)))))
+                ;; Run the binding of the terminating up-event, if
possible.
+                (let* ((stop-point (if (numberp (posn-point (event-end
event)))
+                                       (posn-point (event-end event))
+                                     last-end-point))
+                       (drag-end (if (and stop-point (< stop-point
start-point))
+                                     (overlay-start
mouse-flash-posn-overlay)
+                                   (overlay-end mouse-flash-posn-overlay)))
+                       (drag-start (- (+ (overlay-end
mouse-flash-posn-overlay)
+                                         (overlay-start
mouse-flash-posn-overlay))
+                                      drag-end))
+                       last-command this-command)
+                  (delete-overlay mouse-flash-posn-overlay)
+                  (when (and (= start-hscroll (window-hscroll
start-window))
+                             (or end-point
+                                 (= (window-start start-window)
start-window-start)))
+                    (setq unread-command-events (cons event
unread-command-events)))))))
+       (delete-overlay mouse-flash-posn-overlay))))
+ \f
  ;;; Bindings for mouse commands.

  (define-key global-map [down-mouse-1] 'mouse-drag-region)

Re: mouse.el patch to flash yank position and highlight line

[Richard Stallman]

    * A fix to `mouse-yank-secondary', so you get a reasonable error message if
    the secondary selection is not yet defined (instead of "Wrong type argument:
    char-or-string-p, nil").

That fix should be installed.  Could you please send a patch
for just that fix?

    * `mouse-tear-off-window' does not try to delete the window if it is the
    only one in its frame. Instead, it clones the frame and window. That is, it
    does a "tear-off" at the frame level, instead of the window level.

That seems like a good idea, but the implementation is wrong.  It
should try to do delete-window, and if that fails, then clone the
frame.

As for the bulk of the change, I just don't understand the point.
Your message explains the details from the bottom up, and these
things sound like facilities for doing something else.  What is the
something else?

RE: mouse.el patch to flash yank position and highlight line

[Drew Adams]

>     * A fix to `mouse-yank-secondary', so you get a reasonable
>       error message if the secondary selection is not yet defined
>       (instead of "Wrong type argument: char-or-string-p, nil").
>
> That fix should be installed.  Could you please send a patch
> for just that fix?

-----8<----------------
*** mouse-CVS-2007-07-13.el	Fri Jul 13 14:49:54 2007
--- mouse-CVS-patched-2007-07-14a.el	Sat Jul 14 12:12:34 2007
***************
*** 1631,1637 ****
    ;; Give temporary modes such as isearch a chance to turn off.
    (run-hooks 'mouse-leave-buffer-hook)
    (or mouse-yank-at-point (mouse-set-point click))
!   (insert (x-get-selection 'SECONDARY)))

  (defun mouse-kill-secondary ()
    "Kill the text in the secondary selection.
--- 1631,1640 ----
    ;; Give temporary modes such as isearch a chance to turn off.
    (run-hooks 'mouse-leave-buffer-hook)
    (or mouse-yank-at-point (mouse-set-point click))
!   (let ((secondary (x-get-selection 'SECONDARY)))
!     (if secondary
!         (insert (x-get-selection 'SECONDARY))
!       (error "No secondary selection"))))

  (defun mouse-kill-secondary ()
    "Kill the text in the secondary selection.
-----8<----------------

>     * `mouse-tear-off-window' does not try to delete the window
>       if it is the only one in its frame. Instead, it clones the
>       frame and window. That is, it does a "tear-off" at the frame
>       level, instead of the window level.
>
> That seems like a good idea, but the implementation is wrong.  It
> should try to do delete-window, and if that fails, then clone the
> frame.

I don't see why. If `one-window-p' is true, why would you try to delete the
window? The deletion will never succeed, will it? What's the point? This is
the code:

(save-window-excursion (select-window window)
                       (unless (one-window-p) (delete-window window)))

This was the previous code: (delete-window window)

The new frame was already being created in the old code, in any case; I made
no change in that regard. No explicit frame cloning is done. The window
being deleted is in the old frame; it is deleted because the buffer is now
displayed in a new frame. If the original frame is `one-window-p', then
there is no need to delete the original window, and it is impossible to do
so, in any case.

Please elaborate, if you think I'm misunderstanding you.

> As for the bulk of the change, I just don't understand the point.

Please try again.

> Your message explains the details from the bottom up,

Not at all. At the very beginning I describe the new commands, which is all
there is. I propose that commands `mouse-flash-position-or-M-x' and
`mouse-scan-lines-or-M-:' be bound to `down-mouse-2' and `S-down-mouse-2',
respectively.

Do you not understand the descriptions of those commands? I will try to
explain better, if you let me know what part you don't understand.

Does the following information help?

- `mouse-flash-position-or-M-x' helps with the problem that some people
sometimes have of not being able to tell exactly where the mouse pointer is
pointing. They sometimes accidentally paste a character to the left or right
of what they intended. Some people reported on Emacs Wiki even setting
'mouse-yank-at-point' to 't' just because of this annoyance. With
`mouse-flash-position-or-M-x', you see the yank position highlighted while
the mouse button is depressed. This helps you guide your paste.

- `mouse-scan-lines-or-M-:' highlights the entire line under the pointer as
long as the mouse button is depressed. Use this for whatever you want. I use
it for reading and for visually aligning text that is in the same line.

Both of these track mouse movement. That is, the highlight follows the
pointer during a drag. This means, for example, that you can correct the
yank position before releasing the mouse button to yank. Or you can use
`C-g' before releasing the button, to cancel yanking altogether.

Each of these commands has an alternative functionality for use in the echo
area, where yanking is not possible and there is no need for line
highlighting. This functionality is totally unrelated to the highlighting
features, but I see no reason not to provide it. Just as `C-mouse-1' acts
differently whether you click the mode-line or within a buffer, so clicking
`mouse-2' can act differently whether you click in the echo area or not.

If the echo area were available as a pseudo key like the mode-line is, then
these unrelated features could be implemented by binding different commands,
one for use in the echo area, and one for use elsewhere. Instead, a single
command tests whether the click is in the echo area and acts appropriately.

> and these things sound like facilities for doing something else.  What is
the
> something else?

There is nothing else.

Re: mouse.el patch to flash yank position and highlight line

[Richard Stallman]

    >     * A fix to `mouse-yank-secondary', so you get a reasonable
    >       error message if the secondary selection is not yet defined
    >       (instead of "Wrong type argument: char-or-string-p, nil").
    >
    > That fix should be installed.  Could you please send a patch
    > for just that fix?

    -----8<----------------
    *** mouse-CVS-2007-07-13.el	Fri Jul 13 14:49:54 2007
    --- mouse-CVS-patched-2007-07-14a.el	Sat Jul 14 12:12:34 2007
    ***************
    *** 1631,1637 ****
	;; Give temporary modes such as isearch a chance to turn off.
	(run-hooks 'mouse-leave-buffer-hook)

Please send a change log entry with that patch, and someone will
install it.

Re: mouse.el patch to flash yank position and highlight line

[Richard Stallman]

    > That seems like a good idea, but the implementation is wrong.  It
    > should try to do delete-window, and if that fails, then clone the
    > frame.

    I don't see why. If `one-window-p' is true, why would you try to delete the
    window? The deletion will never succeed, will it? What's the point? This is
    the code:

What I was thinking was, there are many reasons why deleting the
window could fail, and it seems like a good idea to copy the frame
whenever you can't delete the window.

But maybe that isn't really better.

RE: mouse.el patch to flash yank position and highlight line

[Drew Adams]

>     >     * A fix to `mouse-yank-secondary', so you get a reasonable
>     >       error message if the secondary selection is not yet defined
>     >       (instead of "Wrong type argument: char-or-string-p, nil").
>     >
>     > That fix should be installed.  Could you please send a patch
>     > for just that fix?
>
>     -----8<----------------
>     *** mouse-CVS-2007-07-13.el	Fri Jul 13 14:49:54 2007
>     --- mouse-CVS-patched-2007-07-14a.el	Sat Jul 14 12:12:34 2007
>     ***************
>     *** 1631,1637 ****
> 	;; Give temporary modes such as isearch a chance to turn off.
> 	(run-hooks 'mouse-leave-buffer-hook)
>
> Please send a change log entry with that patch, and someone will
> install it.


2007-07-13  Drew Adams  <drew.adams@oracle.com>

      * mouse.el (mouse-yank-secondary): Better error message if no
secondary
        selection.

Re: mouse.el patch to flash yank position and highlight line

[Richard Stallman]

    >     >     * A fix to `mouse-yank-secondary', so you get a reasonable
    >     >       error message if the secondary selection is not yet defined
    >     >       (instead of "Wrong type argument: char-or-string-p, nil").

I installed that bug fix.  Thanks.