### 3.1.137 VoiceFollower

VoiceFollower objects are created by: Note_head_line_engraver.

Standard settings:

> `after-line-breaking` (boolean):

>   `ly:spanner::kill-zero-spanned-time`

>   Dummy property, used to trigger callback for `after-line-breaking`.

> `bound-details` (list):

>   `'((right (attach-dir . 0) (padding . 1.5)) (left (attach-dir . 0) (padding . 1.5)))`

>   An alist of properties for determining attachments of spanners to edges.

> `gap` (dimension, in staff space):

>   `0.5`

>   Size of a gap in a variable symbol.

> `left-bound-info` (list):

>   `ly:line-spanner::calc-left-bound-info`

>   An alist of properties for determining attachments of spanners to edges.

> `non-musical` (boolean):

>   `#t`

>   True if the grob belongs to a `NonMusicalPaperColumn`.

> `right-bound-info` (list):

>   `ly:line-spanner::calc-right-bound-info`

>   An alist of properties for determining attachments of spanners to edges.

> `stencil` (stencil):

>   `ly:line-spanner::print`

>   The symbol to print.

> `style` (symbol):

>   `'line`

>   This setting determines in what style a grob is typeset. Valid choices depend on the `stencil` callback reading this property.

> `X-extent` (pair of numbers)

>   Extent (size) in the X direction, measured in staff-space units, relative to object’s reference point.

> `Y-extent` (pair of numbers)

>   Extent (size) in the Y direction, measured in staff-space units, relative to object’s reference point.

This object supports the following interface(s): grob-interface, line-interface, line-spanner-interface and spanner-interface.

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