Whenever a voice switches to another staff a line connecting the notes
can be printed automatically. This is switched on by setting
PianoStaff.followVoice to true
\context PianoStaff <<
\set PianoStaff.followVoice = ##t
\context Staff \context Voice {
c1
\change Staff=two
b2 a
}
\context Staff=two { \clef bass \skip 1*2 }
>>
Program reference: VoiceFollower.
\showStaffSwitch,
\hideStaffSwitch.
This page is for LilyPond-2.4.5 (stable-branch).