Avoid empty table in documentation of `Global' context.

[lilypond.git] / Documentation / user / changing-defaults.itely

diff --git a/Documentation/user/changing-defaults.itely b/Documentation/user/changing-defaults.itely
index d88bf689156c1882bc1a214a95534a4b32af40cc..fb480d6d2a66f372b8d8c5389a41160e227d6844 100644 (file)
--- a/Documentation/user/changing-defaults.itely
+++ b/Documentation/user/changing-defaults.itely
@@ -56,14 +56,14 @@ notation.  For example, giving each staff a separate time signature.
 @item
 Page layout: changing the appearance of the spacing, line
 breaks, and page dimensions.  These modifications are discussed
 @item
 Page layout: changing the appearance of the spacing, line
 breaks, and page dimensions.  These modifications are discussed

-in @ref{Non-musical notation} and @ref{Spacing issues}.
+in @ref{Non-musical notation}, and @ref{Spacing issues}.

 @end itemize
 
 Internally, LilyPond uses Scheme (a LISP dialect) to provide
 infrastructure.  Overriding layout decisions in effect accesses the
 program internals, which requires Scheme input.  Scheme elements are
 introduced in a @code{.ly} file with the hash mark
 @end itemize
 
 Internally, LilyPond uses Scheme (a LISP dialect) to provide
 infrastructure.  Overriding layout decisions in effect accesses the
 program internals, which requires Scheme input.  Scheme elements are
 introduced in a @code{.ly} file with the hash mark

-@code{#}.@footnote{@ref{Scheme tutorial} contains a short tutorial
+@code{#}.@footnote{@ref{Scheme tutorial}, contains a short tutorial

 on entering numbers, lists, strings, and symbols in Scheme.}
 
 
 on entering numbers, lists, strings, and symbols in Scheme.}
 
 


@@ -437,6 +437,7 @@ This section describes what contexts are, and how to modify them.
 * Changing context default settings::  
 * Defining new contexts::       
 * Aligning contexts::           
 * Changing context default settings::  
 * Defining new contexts::       
 * Aligning contexts::           

+* Vertical grouping of grobs::  

 @end menu
 
 
 @end menu
 
 


@@ -444,7 +445,7 @@ This section describes what contexts are, and how to modify them.
 @subsection Contexts explained
 
 When music is printed, a lot of notational elements must be added to the
 @subsection Contexts explained
 
 When music is printed, a lot of notational elements must be added to the

-input.  For example, compare the input and output of the following example:
+output.  For example, compare the input and output of the following example:

 
 @lilypond[quote,verbatim,relative=2,fragment]
 cis4 cis2. g4
 
 @lilypond[quote,verbatim,relative=2,fragment]
 cis4 cis2. g4


@@ -889,7 +890,7 @@ Here @var{name} is the name of a graphical object, like @code{Stem} or
 @code{NoteHead}, and @var{property} is an internal variable of the
 formatting system (@q{grob property} or @q{layout property}).  The latter is a
 symbol, so it must be quoted.  The subsection @ref{Constructing a
 @code{NoteHead}, and @var{property} is an internal variable of the
 formatting system (@q{grob property} or @q{layout property}).  The latter is a
 symbol, so it must be quoted.  The subsection @ref{Constructing a

-tweak} explains what to fill in for @var{name}, @var{property}, and
+tweak}, explains what to fill in for @var{name}, @var{property}, and

 @var{value}.  Here we only discuss the functionality of this command.
 
 The command
 @var{value}.  Here we only discuss the functionality of this command.
 
 The command


@@ -917,8 +918,8 @@ within the current @context{Staff}.  After the command is interpreted
 all stems are thickened.
 
 Analogous to @code{\set}, the @var{context} argument may be left out,
 all stems are thickened.
 
 Analogous to @code{\set}, the @var{context} argument may be left out,

-causing it to default to @context{Voice}, and adding @code{\once} applies
-the change during one timestep only
+causing the default context @context{Voice} to be used.  Adding
+@code{\once} applies the change during one timestep only.

 
 @lilypond[quote,fragment,verbatim,relative=2]
 c4
 
 @lilypond[quote,fragment,verbatim,relative=2]
 c4


@@ -1004,8 +1005,8 @@ from the music in the @code{\layout} block,
 @}
 @end example
 
 @}
 @end example
 

-Here @code{\Staff} takes the existing definition for context @context{Staff} from the
-identifier @code{\Staff}.
+The @code{\Staff} command brings in the existing definition of the
+staff context so that it can be modified.

 
 The statements
 @example
 
 The statements
 @example


@@ -1100,11 +1101,10 @@ These settings are defined within a @code{\context} block inside a
 @}
 @end example
 
 @}
 @end example
 

-In the following discussion, the example input shown should go on the
-@dots{} in the previous fragment.
+In the following discussion, the example input shown should go in place
+of the @dots{} in the previous fragment.

 
 

-First the context's name is defined.  Instead of @context{Voice} it
-will be called @context{ImproVoice},
+First it is necessary to define a name for the new context:

 
 @example
 \name ImproVoice
 
 @example
 \name ImproVoice


@@ -1118,14 +1118,15 @@ giving the new context an alias @context{Voice},
 \alias Voice
 @end example
 
 \alias Voice
 @end example
 

-The context will print notes, and instructive texts
+The context will print notes and instructive texts, so we need to add
+the engravers which provide this functionality,

 
 @example
 \consists Note_heads_engraver
 \consists Text_engraver
 @end example
 
 
 @example
 \consists Note_heads_engraver
 \consists Text_engraver
 @end example
 

-but only on the center line,
+but we only need this on the center line,

 
 @example
 \consists Pitch_squash_engraver
 
 @example
 \consists Pitch_squash_engraver


@@ -1240,14 +1241,31 @@ ossia = { f4 f f f }
 @end lilypond
 
 
 @end lilypond
 
 

+@node Vertical grouping of grobs
+@subsection Vertical grouping of grobs
+
+The VerticalAlignment and VerticalAxisGroup grobs work together.
+VerticalAxisGroup groups together different grobs like Staff, Lyrics,
+etc. VerticalAlignment then vertically aligns the different grobs
+grouped together by VerticalAxisGroup. There is usually only one
+VerticalAlignment per score but every Staff, Lyrics, etc. has its own
+VerticalAxisGroup. 
+

 
 @node The \override command
 
 @node The \override command

-@section The \override command
+@section The @code{\override} command

 
 In the previous section, we have already touched on a command that
 changes layout details: the @code{\override} command.  In this section,
 
 In the previous section, we have already touched on a command that
 changes layout details: the @code{\override} command.  In this section,

-we will look in more detail at how to use the command in practice.
+we will look in more detail at how to use the command in practice.  The
+general syntax of this command is:
+
+@example
+\override @var{context}.@var{layout_object} #'@var{layout_property} = #@var{value}
+@end example

 
 

+This will set the @var{layout_property} of the specified @var{layout_object},
+which is a member of the @var{context}, to the @var{value}.

 
 @menu
 * Constructing a tweak::        
 
 @menu
 * Constructing a tweak::        


@@ -1255,7 +1273,8 @@ we will look in more detail at how to use the command in practice.
 * Layout interfaces::           
 * Determining the grob property::  
 * Objects connected to the input::  
 * Layout interfaces::           
 * Determining the grob property::  
 * Objects connected to the input::  

-* \set vs. \override::          
+* Using Scheme code instead of \tweak::  
+* \set versus \override::       

 * Difficult tweaks::            
 @end menu
 
 * Difficult tweaks::            
 @end menu
 


@@ -1271,7 +1290,7 @@ Commands which change output generally look like
 @end example
 
 @noindent
 @end example
 
 @noindent

-This means that we must determine these bits of information:
+To construct this tweak we must determine these bits of information:

 
 @itemize
 @item the context: here @context{Voice}.
 
 @itemize
 @item the context: here @context{Voice}.


@@ -1294,10 +1313,17 @@ properties.  To tweak those, use commands in the form
 @funindex \override
 @cindex internal documentation
 
 @funindex \override
 @cindex internal documentation
 

+For many properties, regardless of the data type of the property, setting the
+property to false ( @code{##f} ) will result in turning it off, causing
+Lilypond to ignore that property entirely.  This is particularly useful for
+turning off grob properties which may otherwise be causing problems.
+

 We demonstrate how to glean this information from the notation manual
 and the program reference.
 
 
 We demonstrate how to glean this information from the notation manual
 and the program reference.
 
 

+
+

 @node Navigating the program reference
 @subsection Navigating the program reference
 
 @node Navigating the program reference
 @subsection Navigating the program reference
 


@@ -1358,6 +1384,14 @@ second bit of information listed under @b{See also} in the Notation
 manual.
 @end ignore
 
 manual.
 @end ignore
 

+@ifnothtml
+The programmer's reference is available as an HTML document.  It is
+highly recommended that you read it in HTML form, either online or
+by downloading the HTML documentation.  This section will be much more
+difficult to understand if you are using the 
+PDF manual.
+@end ifnothtml
+

 Follow the link to @internalsref{Fingering}.  At the top of the
 page, you will see
 
 Follow the link to @internalsref{Fingering}.  At the top of the
 page, you will see
 


@@ -1366,8 +1400,8 @@ Fingering objects are created by: @internalsref{Fingering_engraver} and
 @internalsref{New_fingering_engraver}.
 @end quotation
 
 @internalsref{New_fingering_engraver}.
 @end quotation
 

-By clicking around in the program reference, we can follow the
-flow of information within the program, following links like this:
+By following related links inside the program reference, we can follow the
+flow of information within the program:

 
 @itemize @bullet
 
 
 @itemize @bullet
 


@@ -1425,7 +1459,7 @@ The page for @code{Fingering} lists the definitions for the
 @end quotation
 
 @noindent
 @end quotation
 
 @noindent

-which means that the number will be kept at a distance of at least 0.6
+which means that the number will be kept at a distance of at least 0.5

 of the note head.
 
 
 of the note head.
 
 


@@ -1577,7 +1611,7 @@ Fingering_engraver is part of contexts: @dots{} @internalsref{Voice}
 @funindex \tweak
 
 In some cases, it is possible to take a short-cut for tuning graphical
 @funindex \tweak
 
 In some cases, it is possible to take a short-cut for tuning graphical

-objects. For objects that result directly from a piece of the input,
+objects.  For objects that result directly from a piece of the input,

 you can use the @code{\tweak} function, for example
 
 @lilypond[relative=2,fragment,verbatim,ragged-right]
 you can use the @code{\tweak} function, for example
 
 @lilypond[relative=2,fragment,verbatim,ragged-right]


@@ -1589,7 +1623,7 @@ you can use the @code{\tweak} function, for example
 >4-\tweak #'padding #10 -.
 @end lilypond
 
 >4-\tweak #'padding #10 -.
 @end lilypond
 

-As you can see, properties are set directly in the objects directly,
+As you can see, properties are set in the objects directly,

 without mentioning the grob name or context where this should be
 applied.
 
 without mentioning the grob name or context where this should be
 applied.
 


@@ -1597,8 +1631,8 @@ This technique only works for objects that are directly connected to
 an @internalsref{event} from the input, for example
 
 @itemize @bullet
 an @internalsref{event} from the input, for example
 
 @itemize @bullet

-@item note heads, caused by chord-pitch (i.e., notes inside a chord).
-@item articulation signs, caused by articulation instructions.
+@item note heads, caused by chord-pitch (i.e., notes inside a chord)
+@item articulation signs, caused by articulation instructions

 @end itemize
 
 It notably does not work for stems and accidentals (these are caused
 @end itemize
 
 It notably does not work for stems and accidentals (these are caused


@@ -1614,12 +1648,58 @@ to output, so
 @end example
 
 @noindent
 @end example
 
 @noindent

-will not change color.  See @ref{Displaying music expressions} for
+does not change color.  See @ref{Displaying music expressions}, for

 details.
 
 
 details.
 
 

-@node \set vs. \override
-@subsection \set vs. \override
+@node Using Scheme code instead of \tweak
+@subsection Using Scheme code instead of @code{\tweak}
+
+The main disadvantage of @code{\tweak} is its syntactical
+inflexibility.  For example, the following produces a syntax error.
+
+@example
+F = \tweak #'font-size #-3 -\flageolet
+
+\relative c'' @{
+  c4^\F c4_\F
+@}
+@end example
+
+@noindent
+With other words, @code{\tweak} doesn't behave like an articulation
+regarding the syntax; in particular, it can't be attached with
+@samp{^} and @samp{_}.
+
+Using Scheme, this problem can be circumvented.  The route to the
+result is given in @ref{Adding articulation to notes (example)},
+especially how to use @code{\displayMusic} as a helping guide.
+
+@example
+F = #(let ((m (make-music 'ArticulationEvent
+                          'articulation-type "flageolet")))
+       (set! (ly:music-property m 'tweaks)
+             (acons 'font-size -3
+                    (ly:music-property m 'tweaks)))
+       m)
+ 
+\relative c'' @{
+  c4^\F c4_\F
+@}
+@end example
+
+@noindent
+Here, the @code{tweaks} properties of the flageolet object
+@samp{m} (created with @code{make-music}) are extracted with
+@code{ly:music-property}, a new key-value pair to change the
+font size is prepended to the property list with the
+@code{acons} Scheme function, and the result is finally
+written back with @code{set!}.  The last element of the
+@code{let} block is the return value, @samp{m} itself.
+
+
+@node \set versus \override
+@subsection @code{\set} vs. @code{\override}

 
 We have seen two methods of changing properties: @code{\set} and
 @code{\override}.  There are actually two different kinds of
 
 We have seen two methods of changing properties: @code{\set} and
 @code{\override}.  There are actually two different kinds of


@@ -1740,16 +1820,20 @@ one.  For example, if using this with @code{Hairpin},
 
 
 @item Some objects cannot be changed with @code{\override} for
 
 
 @item Some objects cannot be changed with @code{\override} for

-technical reasons. Examples of those are @code{NonMusicalPaperColumn}
+technical reasons.  Examples of those are @code{NonMusicalPaperColumn}

 and @code{PaperColumn}.  They can be changed with the
 and @code{PaperColumn}.  They can be changed with the

-@code{\outputProperty} function, which works similar to @code{\once
-\override}, but uses a different syntax,
+@code{\overrideProperty} function, which works similar to @code{\once
+\override}, but uses a different syntax.

 
 @example
 
 @example

-\outputProperty
+\overrideProperty

 #"Score.NonMusicalPaperColumn"  % Grob name
 #'line-break-system-details     % Property name
 #'((next-padding . 20))         % Value
 @end example
 
 #"Score.NonMusicalPaperColumn"  % Grob name
 #'line-break-system-details     % Property name
 #'((next-padding . 20))         % Value
 @end example
 

+Note, however, that @code{\override}, applied to
+@code{NoteMusicalPaperColumn} and @code{PaperColumn}, still works as
+expected within @code{\context} blocks.
+

 @end itemize
 @end itemize