Re: Springs and rods

[Trevor]

Andrew Bernard wrote 18/01/2019 04:33:12
Subject: Springs and rods

> Yet another annoying question about documentation from me.
>
> After figuring out how to make a glissando longer, and discovering this 
> in the NR under the spanner interface:
>
> minimum-length (dimension, in staff space)
> Try to make a spanner at least this long, normally in the horizontal 
> direction. This requires an appropriate callback for the 
> springs-and-rods property. If added to a Tie, this sets the minimum 
> distance between noteheads.
>
> I can only ask and I think reasonably where is this mystical 
> springs-and-rods mechanism explained? Why does one need to do this:
>
>   \override Glissando #'minimum-length = #4
>   \override Glissando #'springs-and-rods = 
> #ly:spanner::set-spacing-rods
This is acknowledged to be sub-optimal. AIUI, it stems from the multiple 
uses
of the 'minimum-length property. It is used in several interfaces, 
including
lyric-hyphen, multi-measure-rest, etc, as well as spanner. Some of these
require the additional override to work correctly; others don't. The 
solution
would be to separate out the two types of use of the 'minimum-length 
property
into two separate properties, one incorporating set-spacing-rods, but 
the
difficulties involved in doing that seem severe as it's at least 6 years 
since this
was discussed as an issue. I don't understand what the  complexities are 
- maybe
one of the devs could explain further. But in the expectation this would
eventually be fixed (and so the need for documentation  obviated) it has 
never
been documented properly.

Trevor