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bug#4478: 23.1; key bindings for mouse wheel - unclear
From: |
Stefan Monnier |
Subject: |
bug#4478: 23.1; key bindings for mouse wheel - unclear |
Date: |
Fri, 18 Sep 2009 09:34:14 -0400 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/23.1.50 (gnu/linux) |
> 1. Doc bug: The doc is not clear about how to bind the mouse wheel
> (rotations).
Indeed. The way to do it is currently messy and ugly.
> I've been using bindings such as this:
> (define-key map [wheel-down] 'aaa)
> (define-key map [wheel-down] 'bbb)
> (define-key map [C-wheel-down] 'ccc)
> (define-key map [C-wheel-down] 'ddd)
IIUC this is "the right way". And it works under w32 and ns.
Under X11, sadly, mouse-wheel events are usually represented as mouse
clicks for buttons 4 and 5, and there's no way for Emacs to know whether
these correspond to mouse clicks (on mice with more than 3 buttons) or
mouse-wheel events. Worse yet, Emacs doesn't offer an easy way to map
all the variants of `mouse-4' and `mouse-5' (with and without each of
the possible modifiers) to wheel-up and wheel-down.
The code appended below does manage to do such a remap, but as you can
see it's ugly, and worse yet: there can only be one such thing because
it uses the "default" binding. [ And it probably won't work with
xterm-mouse-mode. ]
> (define-key map (vector mouse-wheel-down-event) 'aaa)
> (define-key map (vector mouse-wheel-up-event) 'bbb)
> (define-key map
> (vector (list 'control mouse-wheel-down-event)) 'ccc)
> (define-key map
> (vector (list 'control mouse-wheel-up-event)) 'ddd)
> I haven't tested on GNU/Linux, but I'm assuming this is what to use
> for portable code. Is there a shorter or better way to say this and
> still be portable?
I think this is about as good as it gets for now, yes.
> 1. If there is not, there should be (a shorter way to do this).
The [wheel-down] and friends shown above is what there should be.
Stefan
(define-key function-key-map [t]
'(menu-item "" nil
:filter sm-rewrite-mwheel))
(defun sm-rewrite-mwheel (ignore)
(let* ((events (this-single-command-raw-keys))
(event (unless (zerop (length events))
(aref events (1- (length events))))))
(message "sm-rewrite-mwheel: key=%s" event)
(case (event-basic-type event)
(mouse-4
(let* ((mods (delete 'click (event-modifiers event)))
(new-key (event-convert-list (append mods '(wheel-up))))
(new-event (cons new-key (cdr event))))
(vector new-event)))
(mouse-5
(let* ((mods (delete 'click (event-modifiers event)))
(new-key (event-convert-list (append mods '(wheel-down))))
(new-event (cons new-key (cdr event))))
(vector new-event))))))