### 2.2.17 Clef_engraver

Determine and set reference point for pitches.

Properties (read)

> `clefGlyph` (string)

>   Name of the symbol within the music font.

> `clefPosition` (number)

>   Where should the center of the clef symbol go, measured in half staff spaces from the center of the staff.

> `clefTransposition` (integer)

>   Add this much extra transposition. Values of 7 and -7 are common.

> `clefTranspositionStyle` (symbol)

>   Determines the way the ClefModifier grob is displayed. Possible values are ‘`default`’, ‘`parenthesized`’ and ‘`bracketed`’.

> `explicitClefVisibility` (vector)

>   ‘`break-visibility`’ function for clef changes.

> `forceClef` (boolean)

>   Show clef symbol, even if it has not changed. Only active for the first clef after the property is set, not for the full staff.

This engraver creates the following layout object(s):

Clef and ClefModifier.

`Clef_engraver` is part of the following context(s): DrumStaff, GregorianTranscriptionStaff, KievanStaff, MensuralStaff, PetrucciStaff, Staff, TabStaff and VaticanaStaff.

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