### 3.1.21 BreakAlignGroup

BreakAlignGroup objects are created by: Break_align_engraver.

Standard settings:

> `axes` (list):

>   `'(0)`

>   List of axis numbers. In the case of alignment grobs, this should contain only one number.

> `break-align-anchor` (number):

>   `ly:break-aligned-interface::calc-average-anchor`

>   Grobs aligned to this break-align grob will have their X-offsets shifted by this number. In bar lines, for example, this is used to position grobs relative to the (visual) center of the bar line.

> `break-visibility` (vector):

>   `ly:break-aligned-interface::calc-break-visibility`

>   A vector of 3 booleans, `#(end-of-line unbroken begin-of-line)`. `#t` means visible, `#f` means killed.

> `X-extent` (pair of numbers):

>   `ly:axis-group-interface::width`

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

This object supports the following interface(s): axis-group-interface, break-aligned-interface, grob-interface and item-interface.

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