### 3.2.8 balloon-interface

A collection of routines to put text balloons around an object.

#### User settable properties:

> `annotation-balloon` (boolean)

>   Print the balloon around an annotation.

> `annotation-line` (boolean)

>   Print the line from an annotation to the grob that it annotates.

> `padding` (dimension, in staff space)

>   Add this much extra space between objects that are next to each other.

> `text` (markup)

>   Text markup. See Formatting text.

#### Internal properties:

> `spanner-placement` (direction)

>   The place of an annotation on a spanner. `LEFT` is for the first spanner, and `RIGHT` is for the last. `CENTER` will place it on the broken spanner that falls closest to the center of the length of the entire spanner, although this behavior is unpredictable in situations with lots of rhythmic diversity. For predictable results, use `LEFT` and `RIGHT`.

This grob interface is used in the following graphical object(s): BalloonTextItem, FootnoteItem and FootnoteSpanner.

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