Guide, node Updating translation committishes..
@end ignore
-@c \version "2.15.10"
+@c \version "2.15.20"
@node Changing defaults
@chapter Changing defaults
options available in LilyPond. It is written as a HTML document,
which is available
@c leave the @uref as one long line.
-@uref{http://@/lilypond@/.org/@/doc/@/stable/@/Documentation/@/user/@/lilypond@/-internals/,on@/-line},
+@uref{http://@/lilypond@/.org/@/doc/@/stable/@/Documentation/@/internals/,on@/-line},
and is also included with the LilyPond documentation package.
Internally, LilyPond uses Scheme (a LISP dialect) to provide
Modifications can be made to the @code{Score} context or all
@code{Voice} contexts in a similar way.
-@knownissues
-
-It is not possible to collect context changes in a variable and apply
-them to a @code{\context} definition by referring to that variable.
+Context changes can be placed in a variable and applied to a
+@code{\context} definition by prepending the modification with
+@code{\with}:
+@lilypond[quote,verbatim]
+blubb = \with {
+ fontSize = #-4
+ \override Stem #'thickness = #4.0
+ \remove "Time_signature_engraver"
+}
-The @code{\Staff \RemoveEmptyStaves} will overwrite your current
-@code{\Staff} settings. If you wish to change the defaults for a
-staff which uses @code{\Staff \RemoveEmptyStaves}, you must do so
-after calling @code{\Staff \RemoveEmptyStaves}, ie
+bla = \with {
+ fontSize = #3
+ \override Stem #'thickness = #-2.0
+}
-@example
-\layout @{
- \context @{
- \Staff \RemoveEmptyStaves
+melody = \relative c'' {
+ a4 a a a |
+ a4 a a a |
+}
- \override Stem #'thickness = #4.0
- @}
-@}
-@end example
+\score {
+ <<
+ \new Staff <<
+ \melody
+ s1*0^"Small, thicker stems, no time signature"
+ >>
+ \new Staff \bla <<
+ \melody
+ s1*0^"Different"
+ >>
+ >>
+ \layout {
+ \context {
+ \Staff
+ \blubb
+ }
+ }
+}
+@end lilypond
@c TODO: add \with in here.
\override NoteHead #'style = #'slash
\override Stem #'transparent = ##t
\override Flag #'transparent = ##t
-\override Flag #'transparent = ##t
@end example
All these plug-ins have to cooperate, and this is achieved with a
\override NoteHead #'style = #'slash
\override Stem #'transparent = ##t
\override Flag #'transparent = ##t
- \override Flag #'transparent = ##t
\alias Voice
@}
@end example
TrillPitchGroup - not tried
@end ignore
-These indications affect all notes until they are cancelled.
+These indications affect all notes until they are canceled.
@lilypond[verbatim,quote,relative=2]
c2( c)
* Vertical grouping of grobs::
* Modifying stencils::
* Modifying shapes::
+* Unpure-pure containers::
@end menu
Internals Reference:
@rinternals{TieColumn}.
+@cindex Scheme, pure containers
+@cindex Scheme, unpure containers
+@cindex pure containers, Scheme
+@cindex unpure containers, Scheme
+@cindex horizontal spacing, overriding
+
+@node Unpure-pure containers
+@subsection Unpure-pure containers
+
+Unpure-pure containers are useful for overriding @emph{Y-axis} spacing
+calculations - specifically @code{Y-offset} and @code{Y-extent} - with a
+Scheme function instead of a literal (i.e. a number or pair).
+
+For certain grobs, the @code{Y-extent} is based on the @code{stencil}
+property, overriding the stencil property of one of these will
+require an additional @code{Y-extent} override with an unpure-pure
+container. When a function overrides a @code{Y-offset} and/or
+@code{Y-extent} it is assumed that this will trigger line breaking
+calculations too early during compilation. So the function is not
+evaluated at all (usually returning a value of @samp{0} or
+@samp{'(0 . 0)}) which can result in collisions. A @q{pure} function
+will not affect properties, objects or grob suicides and therefore will
+always have its Y-axis-related evaluated correctly.
+
+Currently, there are about thirty functions that are already considered
+@q{pure} and Unpure-pure containers are a way to set functions not on
+this list as @q{pure}. The @q{pure} function is evaluated @emph{before}
+any line-breaking and so the horizontal spacing can be adjusted
+@q{in time}. The @q{unpure} function is then evaluated @emph{after}
+line breaking.
+
+@warning{As it is difficult to always know which functions are on this
+list we recommend that any @q{pure} functions you create do not use
+@code{Beam} or @code{VerticalAlignment} grobs.}
+
+An unpure-pure container is constructed as follows;
+
+@code{(ly:make-unpure-pure-container f0 f1)}
+
+where @code{f0} is a function taking @var{n} arguments (@var{n >= 1})
+and the first argument must always be the grob. This is the function
+that gives the actual result. @var{f1} is the function being labeled
+as @q{pure} that takes @var{n + 2} arguments. Again, the first argument
+must always still be the grob but the second and third are @q{start}
+and @q{end} arguments.
+
+@var{start} and @var{end} are, for all intents and purposes, dummy
+values that only matter for @code{Spanners} (i.e @code{Hairpin} or
+@code{Beam}), that can return different height estimations based on a
+starting and ending column.
+
+The rest are the other arguments to the first function (which
+may be none if @var{n = 1}).
+
+The results of the second function are used as an approximation of the
+value needed which is then used by the first function to get the real
+value which is then used for fine-tuning much later during the spacing
+process.
+
+@lilypond[verbatim,quote,ragged-right]
+#(define (square-line-circle-space grob)
+(let* ((pitch (ly:event-property (ly:grob-property grob 'cause) 'pitch))
+ (notename (ly:pitch-notename pitch)))
+ (if (= 0 (modulo notename 2))
+ (make-circle-stencil 0.5 0.0 #t)
+ (make-filled-box-stencil '(0 . 1.0)
+ '(-0.5 . 0.5)))))
+
+squareLineCircleSpace = {
+ \override NoteHead #'stencil = #square-line-circle-space
+}
+
+smartSquareLineCircleSpace = {
+ \squareLineCircleSpace
+ \override NoteHead #'Y-extent =
+ #(ly:make-unpure-pure-container
+ ly:grob::stencil-height
+ (lambda (grob start end) (ly:grob::stencil-height grob)))
+}
+
+\new Voice \with { \remove "Stem_engraver" }
+\relative c'' {
+ \squareLineCircleSpace
+ cis4 ces cisis c
+ \smartSquareLineCircleSpace
+ cis4 ces cisis c
+}
+@end lilypond
+
+In the first measure, without the unpure-pure container, the spacing
+engine does not know the width of the note head and lets it collide with
+the accidentals. In the second measure, with unpure-pure containers,
+the spacing engine knows the width of the note heads and avoids the
+collision by lengthening the line accordingly.
+
+Usually for simple calculations nearly-identical functions for both the
+@q{unpure} and @q{pure} parts can be used, by only changing the number
+of arguments passed to, and the scope of, the function.
+
+@warning{If a function is labeled as @q{pure} and it turns out not to
+be, the results can be unexpected.}
+
@node Using music functions
@section Using music functions
must return @code{#t}.
@item @code{@var{@dots{}music@dots{}}}
-@tab normal LilyPond input, using @code{$} to reference arguments
-(eg. @samp{$arg1}).
+@tab normal LilyPond input, using @code{$} (in places where only
+Lilypond constructs are allowed) or @code{#} (to use it as a Scheme
+value or music function argument) to reference arguments
+(eg. @samp{#arg1}).
@end multitable
-
The @code{parser} and @code{location} arguments are mandatory, and
are used in some advanced situations as described in the
@q{Extending} manual (see @rextend{Music functions}). For
@example
boolean?
cheap-list? @emph{(use instead of }@q{list?}@emph{ for faster processing)}
+ly:duration?
ly:music?
+ly:pitch?
markup?
number?
pair?
(parser location padding)
(number?)
#{
- \once \override TextScript #'padding = $padding
+ \once \override TextScript #'padding = #padding
#})
\relative c''' {
(parser location padding tempotext)
(number? string?)
#{
- \once \override Score.MetronomeMark #'padding = $padding
- \tempo \markup { \bold $tempotext }
+ \once \override Score.MetronomeMark #'padding = #padding
+ \tempo \markup { \bold #tempotext }
#})
\relative c'' {
projects / lilypond.git / blobdiff