A glyph's metrics for vertical writing, in glyph space units (thousandths of text space).
public CidVerticalMetrics(double VerticalAdvance, double PositionX, double PositionY)
The vertical component of the displacement vector w1 (its horizontal component is 0); usually negative.
The horizontal component of the position vector v, from the horizontal origin to the vertical origin.
The vertical component of the position vector v.
ISO 32000-2 §9.2.4 (Figure 55) and §9.7.4.3: from the CIDFont's W2, else DW2 (default [880 −1000]) with
v.x half the glyph's width. In vertical writing the glyph is painted with its horizontal origin at the current point minus v
(scaled by the font size), and the pen moves by w1.