A glyph that justification widens to fill the line keeps its Insert Aki
before it at its width, and its own width, which ligature carets stand
in, now starts where the glyph is drawn. Optical kerning measures a pair
from the letter of a cluster rather than from a combining mark whose
advance holds the cluster's Aki.
The SVG test also checks centered and right-aligned lines with Insert Aki.
dotCooCoo
705b688f2b