Re: auto-beaming

[Trevor Daniels]

Hi

This is almost but not quite possible.  You have to use beam-ending 
rules to obtain different beaming for different note durations 
(rather than beat-grouping rules, which apply to all note 
durations).

In 2.12 the beam-ending rules are

   ((end * * 2 4) . ,(ly:make-moment 1 4))
   ((end 1 32 2 4) . ,(ly:make-moment 1 8))
   ((end 1 32 2 4) . ,(ly:make-moment 3 8))

These end all beams at the half-bar (1/4 moment) and 32nd beams at 
the quarter bar (1/8 and 3/8 moments).

You want:

8th note beams to end only at bar end, so you need to revert the 
first rule and add one to end these beams at bar end.

16th note beams to end at the 1/4 moment, so you need to add a rule 
to do this.

32nd note beams also to end at the 1/4 moment (only), so you need to 
revert the
last two rules and add two more to do this.

Here's how to code it:

#(revert-auto-beam-setting '(end * * 2 4) 1 4)
#(revert-auto-beam-setting '(end 1 32 2 4) 1 8)
#(revert-auto-beam-setting '(end 1 32 2 4) 3 8)
#(override-auto-beam-setting '(end 1 8 2 4) 2 4)
#(override-auto-beam-setting '(end 1 16 2 4) 1 4)
#(override-auto-beam-setting '(end 1 32 2 4) 1 4)

To subdivide the beams at 8th notes you need to set the beatLength 
to 1/8 and subdivideBeams to #t:

\set beatLength = #(ly:make-moment 1 8)
\set subdivideBeams = ##t

Unfortunately, this will also subdivide 16th beams too.  This is 
what I meant by "not quite possible".  You would need to turn 
subdivideBeams on and off as required.

Note that this will change in 2.13 - the revert commands will not be 
necessary as these beam-ending rules have been removed.

HTH

Trevor



----- Original Message ----- 
From: "David Bobroff" <address@hidden>
To: <address@hidden>
Sent: Thursday, March 19, 2009 7:17 AM
Subject: auto-beaming


> I'm trying to work out some auto-beaming modifications.
>
> In 2/4 time I want:
>
> 4 8th notes beamed
> 4 16th notes beamed
> 8 32nd notes beamed with a subdivision at the 8th note level
>
> Is this possible?  I understand that I'll need to revert some 
> beaming rules in auto-beam.scm.  Frankly, I get a bit lost when 
> working out which rules need to be reverted.  First, I just need 
> to know if my auto-beaming wish can be made to happen.
>
> -David
>
>
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