* Changing context properties on the fly ::
* Modifying context plug-ins::
* Layout tunings within contexts::
-* Defining context defaults ::
+* Changing context default settings::
+* Defining new contexts::
* Which properties to change::
@end menu
from the music, in the @code{\paper} block,
@example
- \paper {
+ \paper @{
@dots{}
\context @{
\StaffContext
+@refbugs
+
+It is not possible to collect changes in a variable, and apply them to
+one @code{\context} definition by referencing that variable.
+
@node Defining new contexts
@subsection Defining new contexts
\name ImproVoice
\type "Engraver_group_engraver"
\consists "Note_heads_engraver"
- \consists "Text_script_engraver"
+ \consists "Text_engraver"
\consists Pitch_squash_engraver
squashedPosition = #0
\override NoteHead #'style = #'slash
}
\context { \StaffContext
\accepts "ImproVoice"
- }
+ }}
\score { \notes \relative c'' {
- a4 d8 bes8 \new ImproVoice { c4^"ad lib" 4
+ a4 d8 bes8 \new ImproVoice { c4^"ad lib"
c4 c^"undress" c c_"while playing :)" }
a1
- }
+ }}
@end lilypond
@code{\paper} block,
@example
- \paper {
- \context {
+ \paper @{
+ \context @{
@dots{}
- }
- }
+ @}
+ @}
@end example
In the following discussion, the example input shown should go on the
@verbatim
\consists Note_heads_engraver
- \consists Text_script_engraver
+ \consists Text_engraver
@end verbatim
but only on the center line,
}
@end verbatim
-Contexts form hierarchies. We want to hang the @consists{ImproVoice}
-under @consists{Staff}, just like normal @code{Voice}s. Therefore, we
+Contexts form hierarchies. We want to hang the @context{ImproVoice}
+under @context{Staff}, just like normal @code{Voice}s. Therefore, we
modify the @code{Staff} definition with the @code{\accepts}
command,@footnote{The opposite of @code{\accepts} is @code{\denies},
which is sometimes when reusing existing context definitions. }
@end verbatim
-@example
-
@node Which properties to change
@menu
* Line breaking::
* Page layout::
-* Defining contexts::
-* Defining new contexts::
@end menu
@node Line breaking
-@node Defining contexts
-@subsection Defining contexts
-
-@cindex context definition
-@cindex translator definition
-
-The most common way to create a new context definition is by extending
-an existing one. An existing context from the paper block is copied
-by referencing a context identifier:
-
-@example
-\paper @{
- \context @{
- @var{context-identifier}
- @}
-@}
-@end example
-
-@noindent
-Every predefined context has a standard identifier. For example, the
-@code{Staff} context can be referred to as @code{\StaffContext}.
-
-The context can then be modified by setting or changing properties,
-e.g.
-@example
-\context @{
- \StaffContext
- Stem \set #'thickness = #2.0
- defaultBarType = #"||"
-@}
-@end example
-These assignments happen before interpretation starts, so a property
-command will override any predefined settings.
-
-@cindex engraver
-
-@refbugs
-
-It is not possible to collect multiple property assignments in a
-variable, and apply to one @code{\context} definition by
-referencing that variable.
-
-
-
-@node Defining new contexts
-@subsection Defining new contexts
-
-
-It is also possible to define new contexts from scratch. To do this,
-you must define give the new context a name. In the following
-example, a very simple Staff context is created: one that will put
-note heads on a staff symbol.
-
-@example
-\context @{
- \type "Engraver_group_engraver"
- \name "SimpleStaff"
- \alias "Staff"
- \consists "Staff_symbol_engraver"
- \consists "Note_head_engraver"
- \consistsend "Axis_group_engraver"
-@}
-@end example
-
-@noindent
-The argument of @code{\type} is the name for a special engraver that
-handles cooperation between simple engravers such as
-@code{Note_head_engraver} and @code{Staff_symbol_engraver}. This
-should always be @code{Engraver_group_engraver} (unless you are
-defining a Score context from scratch, in which case
-@code{Score_engraver} must be used).
-
-The complete list of context modifiers is the following:
-@itemize @bullet
-@item @code{\alias} @var{alternate-name}:
-This specifies a different name. In the above example,
-@code{\set Staff.X = Y} will also work on @code{SimpleStaff}s.
-
-@item @code{\consistsend} @var{engravername}:
-Analogous to @code{\consists}, but makes sure that
-@var{engravername} is always added to the end of the list of
-engravers.
-
-Engravers that group context objects into axis groups or alignments
-need to be at the end of the list. @code{\consistsend} insures that
-engravers stay at the end even if a user adds or removes engravers.
-
-@item @code{\accepts} @var{contextname}:
-This context can contains @var{contextname} contexts. The first
-@code{\accepts} is created as a default context when events (e.g. notes
-or rests) are encountered.
-
-@item @code{\denies}:
-The opposite of @code{\accepts}.
-
-@item @code{\name} @var{contextname}:
-This sets the type name of the context, e.g. @code{Staff},
-@code{Voice}. If the name is not specified, the translator will not
-do anything.
-@end itemize
-
-@c EOF
-
-
-
-
@node Output details
@section Output details
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