In this section, we show some ways to fine tune the final output of a
piece. We do so using a single measure of a moderately complex piano
piece: a Brahms intermezzo (opus 119, no. 1).
+@cindex Brahms, Johannes
The code for the untuned example shows us some new things.
@lilypondfile[verbatim]{brahms-original.ly}
+
+@cindex dynamics
+@cindex loudness
+@cindex forte
+@cindex crescendo
+@cindex @code{\<}
+@cindex @code{\!}
+
+The crescendo is ended at the half note by the escaped exclamation
+mark @code{\!}.
+
Hairpin dynamics can be indicated using @code{\>} to start a
decrescendo, and @code{\!} to end one. The crescendo is started using
@code{\<} and also ended using @code{\!}. Absolute dynamics can be
-entered using @code{\p}, @code{\mf}, etc.
+entered using @code{\p}, @code{\mf}, etc. All these commands apply to
+the complete chord where they are entered, but for syntactical
+reasons, they must be attached to one of the notes of the chord.
+
+@cindex fingering instructions
Fingering indications are entered simply using @code{-@var{N}}, where
@var{N} is a digit.
@lilypondfile{brahms-tweaked.ly}
+@cindex tuning grob behavior
+
The basic process that we follow is that we override defaults in the
printing system. We do this by setting variables in so-called grobs.
Printed symbols are internally represented by Graphical Objects
etc. The initial values of these settings are set in the Scheme file
@file{scm/grob-description.scm}.
+@cindex slur attachments
+
We start with the slur: the slur in the upper part, running from the F
sharp to the A, runs from stem to stem in the printed edition, while
ours starts from the note head at the left. The following property
different types of Grobs, that may be created in 14 different context
types besides Voice.
+@cindex internal documentation
+@cindex finding grobs
+@cindex grob descriptiosn
+
The interesting information is how you can figure out which properties
to tune for your own scores. To discover this, you must have a copy of
the internals document. This is a set of HTML pages, which should be
``Documentation: other'' on the side bar, click
``lilypond-internals'', under information for users.
+You might want to bookmark either the HTML files on disk, or the one
+on the web. One word of caution is in place here: the internals
+documentation is generated from the definitions that lily uses. For
+that reason, it is strongly tied to the version of LilyPond that you
+use. Before you proceed, please make sure that you are using the
+documentation that corresponds to the LilyPond version that you use.
+
Suppose that you wanted to tune the behavior of the slur. The first
step is to get some general info on slurs in lilypond. Turn to the
-index, and look up slur. The text says
+index, and look up slur. The section on slurs says
@quotation
The grob for this object is @internalsref{Slur}, generally in
@internalsref{Voice} context.
and select ``slur'' (the list is alphabetical.)
Now you get a list of all the properties that the slur object
-supports, along with their default values.
+supports, along with their default values. Among the properties we
+find the @code{attachment} property, leading to
+@example
+ \property Voice.Slur \set #'attachment = #'(stem . stem)
+@end example
+
+If you ran the previous example, you have unknowingly already used
+this kind of command. The @file{ly/property-init.ly} contains the
+definition of @code{\stemUp}
+@example
+ stemUp = \property Voice.Stem \set #'direction = #1
+@end example
We also want to move around the fingering `3'. In the printed edition
The second fingering instruction should be moved up a little, to avoid
a collision with the slur. This could be achieved with
@code{extra-offset}, but in this case, a simpler mechanism also
-works. We insert an empty text between the 5 and note. The empty text
-pushes the fingering instruction away:
+works. We insert an empty text between the 5 and the note. The empty
+text pushes the fingering instruction away:
@example
a^" "^#'(finger "5")
@end example
finger and the note, we have disguised the fingering instruction as a
text: @code{(finger "5")}.
+Normally, one would specify dynamics in a single voice, and start and
+end dynamics (such as @b{f} and @b{p}) will be aligned with
+hairpins. In this case, we want the decrescendo to be in a different
+place from the piano sign. We achieve this by putting the dynamic
+markings in different voices. The crescendo should be above the upper
+staff. This can be forced by the precooked command
+@example
+ \dynamicsUp
+@end example
+
+However, if you do that, the decrescendo will be too close to the
+upper voice, and collide with the stems. Looking at the manual for
+dynamics, we notice that ``Vertical positioning of these symbols is
+handled by the @internalsref{DynamicLineSpanner} grob.''. If we turn
+to the documentation of @code{DynamicLineSpanner}, we find that the
+@code{DynamicLineSpanner} supports several so-called
+`interfaces'. This grob not only puts dynamic objects next to the
+staff (@code{side-position-interface}), but it also groups dynamic
+objects (@code{axis-group-interface}), is considered a dynamic sign
+itself (@code{dynamic-interface}) and is a grob: it has the
+@code{grob-interface}, with all the variables that come with it.
+
+For the moment, we are interested in the side positioning:
+@quotation
+ side-position-interface
-
-@separate
+ Position a victim object (this one) next to other objects (the
+ support). In this case, the direction signifies where to put the
+ victim object relative to the support (left or right, up or down?)
+@end quotation
+Between the grob and its support (in this case: the notes in the voice
+going down), there should be more space. This space is controlled by
+@code{padding}, so we increase it.
@example
- stemDown = \property Voice.Stem \override #'direction = #-1
+ \property Voice.DynamicLineSpanner \override #'padding = #5.0
@end example
-Set a property for all Stem grobs in the current Voice:
-@code{direction} is set to @code{-1}, which encodes down. The setting
-remains in effect until it is reverted.
+This command is almost like the command for setting slur attachments,
+but subtly different in its details. Grob properties can be
+manipulated with two commands: @code{\override} extends the grob
+variables with a setting, and @code{\revert} releases this
+setting. This has a certain theoretical appeal: the operations are
+simple and symmetric. For practical use, it can be cumbersome. Both
+commands act like parentheses: you should carefully balance the use of
+@code{\override} and @code{\revert}. The @code{\set} command is more
+friendly: it first does a @code{\revert} followed by @code{\override}.
+
+Finally, Brahms uses music notation is a slightly unorthodox way. Ties
+usually happen only within one voice. In this piece, the composer
+gladly produces ties that jump voices. We deal with this by faking
+these ties: whenever we need such a tie, we insert a notehead in a
+different voice, and blank the stem. This is done in the following
+snippet of code.
-@separate
@example
- \property Voice.Stem \revert #'direction
+ \property Voice.Stem \set #'transparent = ##t
+ d'
+ \property Voice.Stem \revert #'transparent
@end example
-Revert the to the previous setting. The effect of precisely one
-@code{\stemDown} or @code{\stemUp} is neutralized.
-
-
-@cindex dynamics
-@cindex loudness
-@cindex forte
-@code{\f} places a forte symbol under the chord. The forte applies to
-the whole chord, but the syntax requires that commands like forte and
-arpeggio are attached to a note, so here we attach them to the first
-note.
-
-On the first chord, a crescendo is started with
-@code{\<}. To be precise, the crescendo start is syntactically attached
-to the preceding note, the @code{d}.
-
-@cindex dynamics
-@cindex crescendo
-@cindex @code{\<}
-
-@cindex @code{\!}
-
-The crescendo is ended at the half note by the escaped exclamation
-mark @code{\!}.
+Finally, the last tie is forced up using @code{\tieUp}.
@node An orchestral score
projects / lilypond.git / blobdiff