NULL
and NA
are returned unchanged.
Single element numeric vectors are returned as a character vector with the
number plus a suffix of "px"
.
Single element character vectors must be "auto"
or "inherit"
,
or a number. If the number has a suffix, it must be valid: px
,
%
, em
, pt
, in
, cm
, mm
, ex
,
or pc
. If the number has no suffix, the suffix "px"
is
appended.
Any other value will cause an error to be thrown.