Hi,
?gpar says:
Specifying the value 'NULL' for a parameter is the same as not
specifying any value for that parameter, except for 'col' and
'fill', where 'NULL' indicates not to draw a border or not
to fill
an area (respectively).
However, I get
> library(grid)
> grid.points(gp = gpar(font = 1)) # works fine
> grid.points(gp = gpar(font = 1, fontface = NULL))
Error in validGP(list(...)) : Must specify only one of 'font' and
'fontface'
This happens in 2.3.1 as well as r-devel.
Deepayan