LilyPond Internals Reference: 3.2.68 note-collision-interface

### 3.2.68 note-collision-interface

An object that handles collisions between notes with different stem directions and horizontal shifts. Most of the interesting properties are to be set in note-column-interface: these are `force-hshift` and `horizontal-shift`.

#### User settable properties:

> `merge-differently-dotted` (boolean)

>   Merge note heads in collisions, even if they have a different number of dots. This is normal notation for some types of polyphonic music.

>   `merge-differently-dotted` only applies to opposing stem directions (i.e., voice 1 & 2).

> `merge-differently-headed` (boolean)

>   Merge note heads in collisions, even if they have different note heads. The smaller of the two heads is rendered invisible. This is used in polyphonic guitar notation. The value of this setting is used by note-collision-interface.

>   `merge-differently-headed` only applies to opposing stem directions (i.e., voice 1 & 2).

> `prefer-dotted-right` (boolean)

>   For note collisions, prefer to shift dotted up-note to the right, rather than shifting just the dot.

#### Internal properties:

> `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): NoteCollision.

#### Internals Reference