LilyPond Internals Reference: 3.2.23 dot-column-interface

### 3.2.23 dot-column-interface

Group dot objects so they form a column, and position dots so they do not clash with staff lines.

#### User settable properties:

> `direction` (direction)

>   If `side-axis` is `0` (or `#X`), then this property determines whether the object is placed `#LEFT`, `#CENTER` or `#RIGHT` with respect to the other object. Otherwise, it determines whether the object is placed `#UP`, `#CENTER` or `#DOWN`. Numerical values may also be used: `#UP`=`1`, `#DOWN`=`-1`, `#LEFT`=`-1`, `#RIGHT`=`1`, `#CENTER`=`0`.

#### Internal properties:

> `dots` (array of grobs)

>   Multiple `Dots` objects.

> `positioning-done` (boolean)

>   Used to signal that a positioning element did its job. This ensures that a positioning is only done once.

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

#### Internals Reference