This function is modeled on the element_*
functions used in
ggplot2
to specify graphical properties in themes. It is primarily
used to create the value on the right-hand side of an assignment involving
the props<-
group of setter functions.
A horizontal or vertical rule (hvrule) is actually drawn as long, narrow
rectangle, with a line centered inside it. The narrowness of the
rectangle, and thus how much space the hvrule adds to the table, is
controlled by space
. The thickness of the line inside the
rectangle is controlled by size
. Setting linetype
to 0
means no line will be drawn, but the enclosing rectangle will be. In that
way hvrules can be used to insert extra blank space between rows or
columns of a table.
Quantitative properties size
and space
may be specified
using the ggplot2
function rel()
. This function indicates
that the value is to be interpreted as a multiplier to be applied to
whatever the current value of the property is. For example
space=rel(1.2)
specifies that the space
property of an entry
is to be increased by 20% from its current value.