[linux-audio-user] Re: snd-ls: help with selections

[Kjetil S. Matheussen]

On Wed, 29 Nov 2006, Forest Bond wrote:

> On Wed, Nov 29, 2006 at 04:35:45AM +0100, Kjetil S. Matheussen wrote:
>> Forest Bond:
>>> I am using snd-ls 0.9.7.12.  I have searched through documentation, and
>>> fail to
>>> see how I can define the end point of a selection started with C-space.
>>> Am I
>>> missing something?  I would like to move the cursor into position, press
>>> C-space, move the cursor to a new position, and press some key to have the
>>> selection end there.  I am expecting to see a high-lighted selection at
>>> the end
>>> of that process.
>>
>> I don't know if theres anything built in, but its relatively easy to add a
>> keybinding to do it yourself.
>>
>> To let C-space select both start and end of selection plus cancel it, put
>> the following lines into your .snd-ls file:
>>
>> (bind-key (char->integer #\ ) 4
>> 	  (let ((selstart #f))
>> 	    (lambda ()
>> 	      (let ((set-selstart! (lambda ()
>> 				     (report-in-minibuffer (format #f
>> 				     "Selection start at ~A" (cursor)))
>> 				     (set! selstart (cursor)))))
>> 		(if (c-selection?)
>> 		    (begin
>> 		      (set! (selection-member? #t) #f)
>> 		      (set-selstart!))
>> 		    (if selstart
>> 			(begin
>> 			  (c-set-selection! (c-selected-sound) 0 (min
>> 			  selstart (cursor)) (max selstart (cursor)))
>> 			  (report-in-minibuffer "")
>> 			  (set! selstart #f))
>> 			(set-selstart!)))))))
>> (load-from-path "snd_conffile.scm")
>
> Hmm.  I definately wouldn't have come up with that.

Well. :-)

It was ment to be a complete well-working example. You could get away with
something like this:

(bind-key (char->integer #\n) 4
   (lambda ()
      (set! (selection-frames) (- (cursor) (selection-position))))))

but the first one is much better. And this one is even better:

(bind-key (char->integer #\ ) 4
 	  (lambda ()
 	    (let* ((snd (c-selected-sound))
 		   (old-selstart (c-get snd 'c-space-selstart #f))
 		   (new-selstart (cursor)))
 	      (cond ((c-selection?)
 		     (set! (selection-member? #t) #f))
 		    (old-selstart
 		     (c-set-selection! (c-selected-sound) 0 (min old-selstart new-selstart) (max old-selstart new-selstart))
 		     (set! new-selstart! #f)))
 	      (report-in-minibuffer (if new-selstart
 					(format #f "Selection starts at ~A" new-selstart)
 					""))
 	      (c-put snd 'c-space-selstart new-selstart)))))



>  How do people normally
> terminate a selection?  Or is it just always done with the mouse?

Yeah, I just use the mouse. Its not very efficient, but I don't
terminate a selection very often. I'm going to add the above code
to snd-ls though.


>  If so, why
> have the default C-space binding at all?
>

Don't know...