### 2.2.63 Ledger_line_engraver

Create the spanner to draw ledger lines, and notices objects that need ledger lines.

This engraver creates the following layout object(s):

LedgerLineSpanner.

`Ledger_line_engraver` is part of the following context(s): DrumStaff, GregorianTranscriptionStaff, KievanStaff, MensuralStaff, PetrucciStaff, RhythmicStaff, Staff, TabStaff and VaticanaStaff.

#### Internals Reference v2.18.2 (稳定分支).