### 3.2.55 ledger-line-spanner-interface

This spanner draws the ledger lines of a staff. This is a separate grob because it has to process all potential collisions between all note heads. The thickness of ledger lines is controlled by the `ledger-line-thickness` property of the StaffSymbol grob.

#### User settable properties:

> `gap` (dimension, in staff space)

>   Size of a gap in a variable symbol.

> `length-fraction` (number)

>   Multiplier for lengths. Used for determining ledger lines and stem lengths.

> `minimum-length-fraction` (number)

>   Minimum length of ledger line as fraction of note head size.

#### Internal properties:

> `note-heads` (array of grobs)

>   An array of note head grobs.

This grob interface is used in the following graphical object(s): LedgerLineSpanner.

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