LilyPond Internals Reference: 3.2.104 outside-staff-axis-group-interface

### 3.2.104 `outside-staff-axis-group-interface`

A vertical axis group on which outside-staff skyline calculations are done.

#### User settable properties:

`outside-staff-placement-directive` (symbol)

  One of four directives telling how outside staff objects should be placed.

  - `left-to-right-greedy` – Place each successive grob from left to right.
  - `left-to-right-polite` – Place a grob from left to right only if it does not potentially overlap with another grob that has been placed on a pass through a grob array. If there is overlap, do another pass to determine placement.
  - `right-to-left-greedy` – Same as `left-to-right-greedy`, but from right to left.
  - `right-to-left-polite` – Same as `left-to-right-polite`, but from right to left.

#### Internal properties:

`vertical-skyline-elements` (array of grobs)

  An array of grobs used to create vertical skylines.

This grob interface is used in the following graphical object(s): `BassFigureLine`, `System` and `VerticalAxisGroup`.

#### LilyPond – Internals Reference v2.24.4 (stable-branch).