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Using the self-alignment-interface

Self-aligning objects horizontally

The horizontal alignment of an object which supports the self-alignment-interface is controlled by the value of the self-alignment-X property, provided the object’s X-offset property is set to ly:self-alignment-interface::x-aligned-on-self. self-alignment-X may be given any real value, in units of half the total X extent of the object. Negative values move the object to the right, positive to the left. A value of 0 centers the object on the reference point of its parent, a value of -1 aligns the left edge of the object on the reference point of its parent, and a value of 1 aligns the right edge of the object on the reference point of its parent. The symbols LEFT, CENTER, and RIGHT may be used instead of the values -1, 0, and 1, respectively.

Normally the \override command would be used to modify the value of self-alignment-X, but the \tweak command can be used to separately align several annotations on a single note:

a'
-\tweak self-alignment-X -1
^"left-aligned"
-\tweak self-alignment-X 0
^"center-aligned"
-\tweak self-alignment-X #RIGHT
^"right-aligned"
-\tweak self-alignment-X -2.5
^"aligned further to the right"

Self-aligning objects vertically

Objects may be aligned vertically in an analogous way to aligning them horizontally if the Y-offset property is set to ly:self-alignment-interface::y-aligned-on-self. However, other mechanisms are often involved in vertical alignment: the value of Y-offset is just one variable taken into account. This may make adjusting the value of some objects tricky. The units are just half the vertical extent of the object, which is usually quite small, so quite large numbers may be required. A value of -1 aligns the lower edge of the object with the reference point of the parent object, a value of 0 aligns the center of the object with the reference point of the parent, and a value of 1 aligns the top edge of the object with the reference point of the parent. The symbols DOWN, CENTER, and UP may be substituted for -1, 0, and 1, respectively.

Self-aligning objects in both directions

By setting both X-offset and Y-offset, an object may be aligned in both directions simultaneously.

The following example shows how to adjust a fingering mark so that it nestles close to the note head.

a'
-\tweak self-alignment-X 0.5  % move horizontally left
-\tweak Y-offset #ly:self-alignment-interface::y-aligned-on-self
-\tweak self-alignment-Y -1  % move vertically up
-3  % third finger