### 3.1.62 LeftEdge

LeftEdge objects are created by: Break_align_engraver.

Standard settings:

> `break-align-anchor` (number):

>   `ly:break-aligned-interface::calc-extent-aligned-anchor`

>   Grobs aligned to this break-align grob will have their X-offsets shifted by this number. In bar lines, for example, this is used to position grobs relative to the (visual) center of the bar line.

> `break-align-symbol` (symbol):

>   `'left-edge`

>   This key is used for aligning and spacing breakable items.

> `break-visibility` (vector):

>   `#(#t #f #t)`

>   A vector of 3 booleans, `#(end-of-line unbroken begin-of-line)`. `#t` means visible, `#f` means killed.

> `extra-spacing-height` (pair of numbers):

>   `'(+inf.0 . -inf.0)`

>   In the horizontal spacing problem, we increase the height of each item by this amount (by adding the ‘car’ to the bottom of the item and adding the ‘cdr’ to the top of the item). In order to make a grob infinitely high (to prevent the horizontal spacing problem from placing any other grobs above or below this grob), set this to `(-inf.0 . +inf.0)`.

> `non-musical` (boolean):

>   `#t`

>   True if the grob belongs to a `NonMusicalPaperColumn`.

> `space-alist` (list):

>   `'((ambitus extra-space . 2.0) (breathing-sign minimum-space . 0.0) (cue-end-clef extra-space . 0.8) (clef extra-space . 0.8) (cue-clef extra-space . 0.8) (staff-bar extra-space . 0.0) (key-cancellation extra-space . 0.0) (key-signature extra-space . 0.8) (time-signature extra-space . 1.0) (custos extra-space . 0.0) (first-note fixed-space . 2.0) (right-edge extra-space . 0.0))`

>   A table that specifies distances between prefatory items, like clef and time-signature. The format is an alist of spacing tuples: `(break-align-symbol type . distance)`, where type can be the symbols `minimum-space` or `extra-space`.

> `X-extent` (pair of numbers):

>   `'(0 . 0)`

>   Extent (size) in the X direction, measured in staff-space units, relative to object’s reference point.

This object supports the following interface(s): break-aligned-interface, grob-interface and item-interface.

#### Internals Reference v2.18.2 (稳定分支).