pub fn convert_unit_ratio(unit_arg: &str) -> (i64, i64)Expand description
Convert a unit name into the exact TeX (num, den) fraction such that a
dimension of value units is floor(round(value·65536)·num/den) scaled
points (see numeric_ops::fixpoint_unit).
Physical units use TeX’s set_conversion(num)(denom) fractions verbatim
(tex.web §458, lines 9020-9032): in=7227/100, pc=12/1, cm=7227/254, mm=7227/2540, bp=7227/7200, dd=1238/1157, cc=14856/1157, plus pt=1/1 and
sp=1/65536. px follows LaTeXML in aliasing bp. Font-relative units
(em/ex/mu) return (metric_sp, 65536), matching tex.web §8983’s
nx_plus_y(_, v, xn_over_d(v, f, 65536)) for internal units. This is the
exact-integer counterpart of convert_unit; each physical entry satisfies
convert_unit(u) == 65536·num/den.