Defines the size of a rendered face of a font, in pixels, horizontally and
vertically. A vertical scale of y pixels means that the distance betwen
the ascent and descent lines (see VMetrics) of the face will be y
pixels. If x and y are equal the scaling is uniform. Non-uniform scaling
by a factor f in the horizontal direction is achieved by setting x equal
to f times y.
SharedBytes handles the lifetime of font data used in RustType. The data
is either a shared reference to externally owned data, or managed by
reference counting. SharedBytes can be conveniently used with From and
Into, and dereferences to the contained bytes.