[R] Darker markers for symbols in lattice

[Deepayan Sarkar]

On Sun, Mar 29, 2009 at 12:35 PM, Naomi B. Robbins
<nbrgraphs at optonline.net> wrote:
> In lattice, using the command trellis.par.get for superpose.symbol, plot,
> symbol and/or dot.symbol shows that we can specify alpha, cex, col, fill
> (for  superpose.symbol and plot.symbol), font, and pch.  Trial and error
> shows that the font affects letters but not pch=1 or pch=3 (open circles
> and plus signs.) I want to use open circles and plus signs, keep the colors
> and cex  I've specified but make the symbols bolder, much the way a
> higher lwd makes lines bolder.  Does anyone know of a library that
> does that or can anyone think of a workaround to make the markers
> stand out better without making them larger?

?grid::gpar lists 'lex' as a "Multiplier applied to line width", and
that seems to work when supplied as a top-level argument (though not
in the parameter settings):

xyplot(1:10 ~ 1:10, pch = c(1, 3), cex = 2, lex = 3)

I'm not sure if 'lwd' should have the same effect (it does in base graphics).

-Deepayan