The alignment of the origin, relative to the size of the box.
This is equivalent to setting an origin based on the size of the box. If it is specified at the same time as an offset, both are applied.
Source
FractionalOffset get alignment => _alignment;
Source
set alignment (FractionalOffset newAlignment) {
assert(newAlignment == null || (newAlignment.dx != null && newAlignment.dy != null));
if (_alignment == newAlignment)
return;
_alignment = newAlignment;
markNeedsPaint();
}