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
How is one meant to know what an 'appropriate callback is'? What other callback would one use? And what for?
I have to honestly say that if I could ever understand the lilypond internals I would readily volunteer to rewrite these sections in the NR, which occur far too often I am afraid. I've been using lilypond heavily for years, and sections like this simply make me feel dumb. Perhaps I missed something fundamental along the learning curve.
None of this criticism is aimed at any person. I am well aware this sort of manual is reference and not tutorial. There used to be a series of computer publications called [X]: The Missing Manual. I feel we need the missing manual for lilypond. I don't know enough to write it.
All help most appreciated.