GNU LilyPond

-- --

beam-interface

A beam.

#'thickness= weight of beams, in staffspace

We take the least squares line through the ideal-length stems, and then damp that using

damped = tanh (slope)

this gives an unquantized left and right position for the beam end. Then we take all combinations of quantings near these left and right positions, and give them a score (according to how close they are to the ideal slope, how close the result is to the ideal stems, etc.). We take the best scoring combination.

auto-knee-gap (number):

If a gap is found between noteheads where a horizontal beam fits that is larger than this number, make a kneed beam. Default value: (unset)

beamed-stem-shorten (list):

shorten beamed stems in forced direction. Default value: (unset)

chord-tremolo (boolean):

if set, this beam is a tremolo. TODO: use interface for this! Default value: (unset)

concaveness-gap (number):

A beam is considered to be concave if the distance of an inner notehead to the line between two outer noteheads is bigger than this gap. Default value: (unset)

concaveness-threshold (number):

A beam is considered to be concave is concaveness is bigger than this threshold. Concaveness is calculated as the sum of the vertical distances of inner noteheads that fall outside the interval of the two outer noteheads, to the vertically nearest outer notehead, divided by the square of the inner notes involved. Default value: (unset)

damping (integer):

amount of beam slope damping should beam slope be damped? 0: no, 1: yes, 100000: horizontal beams . Default value: (unset)

dir-function (procedure):

function of type (count total)->direction. Default value: beam-dir-majority, also available: beam-dir-mean, beam-dir-median.

The ways to calculate the direction of a beam work as follows:

majority

number count of up or down notes

mean

mean center distance of all notes

median

mean centre distance weighted per note

Default value: (unset)

flag-width-function (procedure):

Procedure that computes the width of a half-beam (a non-connecting beam.). Default value: (unset)

french-beaming (boolean):

Use French beaming style: stems stop at innermost beams. Default value: (unset)

gap (number):

Size of a gap in a variable symbol. Default value: (unset)

knee (boolean):

Is this beam a knee? Default value: (unset)

least-squares-dy (number):

ideal beam slope, without damping. Default value: (unset)

neutral-direction (direction):

Where to go if we're on the neutral position of the staff (by default, the middle of the staff; see also grob-property neutral-position). [Ross] has the following to say about this: Some engravers consider the middle line neutral, and take the option of using either up- or down-stems for notes that fall on it. However, more up-to-date engraving no longer permits an option; now a down-stem is always appropriate. Default value: (unset)

position-callbacks (list):

list of functions set spanner positions. Default value: (unset)

positions (pair):

cons of staff positions (LEFT . RIGHT Default value: (unset)

quant-score (number):

Beam quanting score - can be stored for debugging Default value: (unset)

shorten (number):

the amount of space that a stem should be shortened (DOCME!) Default value: (unset)

space-function (procedure):

return interbeam space given Beam grob and multiplicity. Default value: (unset)

thickness (number):

thickness, measured in stafflinethickness. Default value: (unset)

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Copyright (c) 1997--2002 Han-Wen Nienhuys and Jan Nieuwenhuizen.

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