LilyPond program-reference: 3.1.104 System

### 3.1.104 System

System objects are not created by any engraver.

Standard settings:

> `axes` (list):

>   `'(0 1)`

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

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

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

>   Hard coded extent in X direction.

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

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

>   Hard coded extent in Y direction.

> `vertical-skylines` (unknown):

>   `ly:axis-group-interface::calc-skylines`

>   Two skylines, one above and one below this grob.

> `max-stretch` (number):

>   `ly:axis-group-interface::calc-max-stretch`

>   The maximum amount that this `VerticalAxisGroup` can be vertically stretched (for example, in order to better fill a page).

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

#### Internals Reference