5.3.3 The \override command
There is a special type of context property: the grob
description. Grob descriptions are named in StudlyCaps
(starting with capital letters). They contain the
‘default settings’ for a particular kind of grob as an
association list. See ‘scm/define-grobs.scm’
to see the settings for each grob description. Grob descriptions
are modified with \override.
The syntax for the \override command is
\override [context.]GrobName.property = #value
For example, we can increase the thickness of a note stem by
overriding the thickness property of the Stem
object:
c''4 c'' \override Voice.Stem.thickness = #3.0 c''4 c''
If no context is specified in an \override, the bottom
context is used:
\override Staff.Stem.thickness = #3.0
<<
\relative {
e''4 e
\override Stem.thickness = #0.5
e4 e
} \\
\relative {
c''4 c c c
}
>>
Some tweakable options are called ‘subproperties’ and reside inside properties. To tweak those, use commands in the form
\override Stem.details.beamed-lengths = #'(4 4 3)
or to modify the ends of spanners, use a form like these
\override TextSpanner.bound-details.left.text = "left text" \override TextSpanner.bound-details.right.text = "right text"
The effects of \override can be undone by \revert.
The syntax for the \revert command is
\revert [context.]GrobName.property
For example,
\relative {
c''4
\override Voice.Stem.thickness = #3.0
c4 c
\revert Voice.Stem.thickness
c4
}
The effects of \override and \revert apply to all
grobs in the affected context from the current time forward:
<<
\relative {
e''4
\override Staff.Stem.thickness = #3.0
e4 e e
} \\
\relative {
c''4 c c
\revert Staff.Stem.thickness
c4
}
>>
\once can be used with \override or \revert
to affect only the current time step:
<<
\relative c {
\override Stem.thickness = #3.0
e''4 e e e
} \\
\relative {
c''4
\once \override Stem.thickness = #3.0
c4 c c
}
>>
See also
Internals Reference: Backend