Re: Distance of secondary beams

[Abraham Lee]

Hi, Urs!

On Tue, Jan 17, 2017 at 8:26 AM, Malte Meyn <address@hidden> wrote:

Am 17.01.2017 um 11:43 schrieb Urs Liska:
> I don't find the appropriate property to modify the distance between
> secondary stems. Attached you'll find the result of \override
> Beam.beam-thickness = 0.15, and I need to adjust the beams to be closer
> together, e.g. to 0.5 staff spaces. I don't see any promising properties
> in Beam and Beam Interface.

It’s Beam.gap or Beam.beam-gap or something similar.

I'm not sure why the calculation for this is so convoluted. Perhaps studying the source code more would enlighten me. Anyways, the property you are looking for is 'length-fraction. The relation to beam spacing depends on the number of beams, as described in the function get_beam_translation, line 114 of lily/beam.cc.

The basic equation goes like this:

if beam_count < 4:

   beam_dy = (2 * staff_space * fract + line * fract - beam_thickness) / 2.0

else:

  beam_dy = (3 * staff_space * fract + line * fract - beam_thickness) / 3.0

As a reference, this means that the beam gap, IIUC, for a beam-thickness of 0.48 (the default) and length-fraction of 1.0, is about 1/3 of a staff-space for beam-count<4 (but I haven't taken any actual measurements to confirm this).

HTH,

Abraham