RE: key bindings for mouse wheel

[Drew Adams]

Resending. Does no one know whether `wheel-down' is platform independent and
what the proper, portable way to bind mouse wheel events is?


> From: Drew Adams Sent: Sunday, August 17, 2008 5:47 PM 
> 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)
> 
> Reading some mail on (I think) help-gnu-emacs got me a bit 
> confused however. It gave me the impression that such
> bindings were only for MS Windows and that on
> GNU/Linux `mouse-4' and `mouse-5' must be used instead of 
> `wheel-down' and `wheel-up'. (That sounds odd; I'd expect
> `mouse-4' and `mouse-5' to be a fourth
> and fifth mouse button, as they are on Windows.)
> 
> I looked in the Elisp manual, but I didn't find anything specifically
> recommending how one should bind mouse wheel events. I was 
> assuming that `wheel-down' was platform independent, but now
> I have a doubt.
> 
> The Elisp doc (node Misce Events) speaks about events such as 
> (wheel-up POSITION), but it doesn't speak about just what to
> use when binding such keys. Further, it says that events such
> as (wheel-up POSITION) are not generated on some systems and
> that on those systems "`mouse-4' and `mouse-5' are used
> instead". (Why is that?)
> 
> It does say this, however: "For portable code, use the variables
> `mouse-wheel-up-event' and `mouse-wheel-down-event'", and 
> then it goes on to say where those variables are defined (why?).
> 
> So after a bit of fiddling I switched to this:
> 
> (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. Am I missing something? Is there a
> shorter or better way to say this and still be portable?
> 
> Does anyone else think:
> 
> 1. There should be a shorter way to do this?
> 
> 2. Or, if not, this should at least be documented clearly as 
>    the way to bind mouse wheel events?
> 
> [I would even expect the Emacs manual to tell you how to bind 
> mouse-wheel key sequences... But AFAICT the Emacs manual isn't
> too helpful for even the basics about key binding. I'm
> sending a separate mail about that.]