Re: making a Tie more parabolic

[tisimst]

Kieren MacMillan wrote
> I tried that… Unfortunately, it says “More information on the allowed
> parameters for a grob can be found by looking at the top of the Internals
> Reference page for each interface having a details property.” and I
> haven’t been able to find the “more information” they’re talking about!
> Any hints, for example, on what ‘ratio' actually does, or
> 'multi-tie-region-size’?

Kieren,

I think "ratio" is supposed to do what you want, but as I played around with
the properties (see below), I found that "height-limit" controlled the
effect of "ratio". Seems like a "bug" to me that increasing "ratio" doesn't
change the shape of the tie curve very much if the tie is at its
"height-limit", but maybe it's my ignorance at play here.

I took a look into the source code and here's what it says about each of the
"details" properties (found in 2.19.15 "lily/tie.cc" with the default values
found on IR web page and in "define-grobs.scm"):

---------------------------------------------------------------------

- height-limit (default = 1.0)
The maximum height allowed for this tie.

- ratio (default = 0.33)
Parameter for tie shape. The higher this number, the quicker the slur
attains its height-limit.

- between-length-limit (default = 1.0)
This detail is currently unused.

- wrong-direction-offset-penalty (default = None)
Demerit for ties that are offset in the wrong direction.

- min-length (default = None)
If the tie is shorter than this amount (in staff-spaces) an increasingly
large length penalty is incurred.

- min-length-penalty-factor (default = 26.0)
Demerit factor for tie lengths shorter than "min-length".

- center-staff-line-clearance (default = 0.6)
If the center of the tie is closer to a staff line than this amount, an
increasingly large staff line collision penalty is incurred.

- tip-staff-line-clearance (default = 0.45)
If the tips of the tie are closer to a staff line than this amount, an
increasingly large staff line collision penalty is incurred.

- staff-line-collision-penalty (default = None)
Demerit factor for ties whose tips or center come close to staff lines.

- dot-collision-clearance (default = None)
If the tie comes closer to a dot than this amount, an increasingly large dot
collision penalty is incurred.

- dot-collision-penalty (default = None)
Demerit factor for ties which come close to dots.

- note-head-gap (default = 0.2)
The distance (in staff-spaces) by which the ends of the tie are offset
horizontally from the center line through the note head.

- stem-gap (default = 0.35)
The distance (in staff-spaces) by which the ends of the tie are offset
horizontally from a stem which is on the same side of the note head as the
tie.

- tie-column-monotonicity-penalty (default = None)
Demerit if the y-position of this tie in the set of ties being considered is
less than the y-position of the previous tie.

- tie-tie-collision-distance (default = 0.45)
If this tie is closer than this amount to the previous tie in the set being
considered, an increasingly large tie-tie collision penalty is incurred.

- tie-tie-collision-penalty (default = 25.0)
Demerit factor for a tie in the set being considered which is close to the
previous one.

- horizontal-distance-penalty-factor (default = 10.0)
Demerit factor for ties in the set being considered which are horizontally
distant from the note heads.

- vertical-distance-penalty-factor (default = 7.0)
Demerit factor for ties in the set being considered which are vertically
distant from the note heads.

- same-dir-as-stem-penalty (default = 8.0)
Demerit if tie is on the same side as a stem or on the opposite side to the
one specified.

- intra-space-threshold (default = 1.25)
If the tie's height (in half staff-spaces) is less than this it is
positioned between two adjacent staff lines; otherwise it is positioned to
straddle a staff line further from the note heads.

- outer-tie-length-symmetry-penalty-factor (default = 10.0)
Demerit factor for ties horizontally positioned unsymmetrically with respect
to the two note heads.

- outer-tie-vertical-distance-symmetry-penalty-factor (default = 10.0)
Demerit factor for ties vertically positioned unsymmetrically with respect
to the two note heads.

- outer-tie-vertical-gap (default = 0.25)
Amount (in half staff-spaces) by which a tie is moved away from the note
heads if it is closer to either of them than 0.25 half staff-spaces.

- skyline-padding (default = None)
Padding of the skylines around note heads in chords.

- single-tie-region-size (default = 4)
The number of candidate ties to generate when only a single tie is required. 
Successive candidates differ in their initial vertical position by half a
staff-space.

- multi-tie-region-size (default = 3)
The number of variations that are tried for the extremal ties in a chord. 
Variations differ in their initial vertical position by half a staff-space.

---------------------------------------------------------------------

HTH,
Abraham

P.S.

Developers,

It certainly does say that these are supposed to be visible in the IR, but
why aren't they? What can we do to get things like this there? I'm happy to
assist if I can be given some direction...





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