### 2.2.117 Stem_engraver

Create stems and single-stem tremolos. It also works together with the beam engraver for overriding beaming.

Music types accepted:

tremolo-event and tuplet-span-event

Properties (read)

> `stemLeftBeamCount` (integer)

>   Specify the number of beams to draw on the left side of the next note. Overrides automatic beaming. The value is only used once, and then it is erased.

> `stemRightBeamCount` (integer)

>   See `stemLeftBeamCount`.

> `tremoloFlags` (integer)

>   The number of tremolo flags to add if no number is specified.

> `whichBar` (string)

>   This property is read to determine what type of bar line to create.

>   Example:

>   >     \set Staff.whichBar = ".|:"

>   This will create a start-repeat bar in this staff only. Valid values are described in ‘`scm/bar-line.scm`’.

This engraver creates the following layout object(s):

Stem and StemTremolo.

`Stem_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, KievanVoice, MensuralVoice, NullVoice, PetrucciVoice, TabVoice and Voice.

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