their appearance and behaviour. Some of these properties are common
to all spanners; others are restricted to a sub-set of the spanners.
-All spanners support the @code{spanner-interface}. A few, esentially
+All spanners support the @code{spanner-interface}. A few, essentially
those that draw a straight line between the two objects, support in
addition the @code{line-spanner-interface}.
@end lilypond
This property is not effective for all spanners. For example,
-seting it to @code{#t} has no effect on slurs or phrasing slurs
+setting it to @code{#t} has no effect on slurs or phrasing slurs
or on other spanners for which terminating on the bar line would
not be meaningful.
@node Aligning objects
@subsection Aligning objects
-Graphical objects which support the @code{self-alignment-interface} and/or
-the @code{side-position-interface} can be
-aligned to a previously placed object in a variety of ways. For a list of these objects, see
+Graphical objects which support the @code{self-alignment-interface}
+and/or the @code{side-position-interface} can be aligned to a previously
+placed object in a variety of ways. For a list of these objects, see
@rinternals{self-alignment-interface} and @rinternals{side-position-interface}.
All graphical objects have a reference point, a horizontal extent and a
vertical extent. The horizontal extent is a pair of numbers
giving the displacements from the reference point of the left and
-right edges, displacements to the left being negative. The
-vertical extent is a pair of numbers giving the displacement from
-the reference point to the bottom and top edges, displacements down
-being negative.
+right edges, displacements to the left being negative. The vertical
+extent is a pair of numbers giving the displacement from the reference
+point to the bottom and top edges, displacements down being negative.
An object's position on a staff is given by the values of the
@code{X-offset} and @code{Y-offset} properties. The value of
-@code{X-offset} gives the displacement from the x coordinate of
+@code{X-offset} gives the displacement from the X coordinate of
the reference point of the parent object, and the value of
@code{Y-offset} gives the displacement from the center line of the
-staff. The values of @code{X-offset} and
-@code{Y-offset} may be set directly or may be set to be calculated
-by procedures in order to achieve alignment with the parent object
-in several ways.
+staff. The values of @code{X-offset} and @code{Y-offset} may
+be set directly or may be set to be calculated by procedures in order
+to achieve alignment with the parent object.
@warning{Many objects have special positioning considerations which
cause any setting of @code{X-offset} or @code{Y-offset} to be
ignored or modified, even though the object supports the
-@code{self-alignment-interface}.}
+@code{self-alignment-interface}. Overriding the @code{X-offset}
+or @code{Y-offset} properties to a fixed value causes the respective
+@code{self-alignment} property to be disregarded.}
-For example, an accidental can be repositioned
-vertically by setting @code{Y-offset} but any changes to
-@code{X-offset} have no effect.
+For example, an accidental can be repositioned vertically by setting
+@code{Y-offset} but any changes to @code{X-offset} have no effect.
-Rehearsal marks may be aligned with
-breakable objects such as bar lines, clef symbols, time signature
-symbols and key signatures. There are special properties to be
-found in the @code{break-aligned-interface} for positioning rehearsal
-marks on such objects.
+Rehearsal marks may be aligned with breakable objects such as bar
+lines, clef symbols, time signature symbols and key signatures. There
+are special properties to be found in the @code{break-aligned-interface}
+for positioning rehearsal marks on such objects.
+
+@seealso
+@ref{Using the break-alignable-interface},
+@rextend{Callback functions}.
@menu
* Setting X-offset and Y-offset directly::
projects / lilypond.git / blobdiff