nubAlign property
Horizontal position of the nub, 0 (reading-start) .. 1 (reading-end) of the bubble width — physical left..right in LTR, physical right..left in RTL (ENH-38), so a caller says "near the start of the thing it's pointing at" without caring which locale is active. Clamped away from the rounded corners inside the painter.
Implementation
final double nubAlign;