Try this: with(trees, symbols(Height, Volume, circles=Girth/24, inches=FALSE, fg = "gray30", bg = sapply(apply(rbind(col2rgb(gray(seq(0,1, l = 10)))/255, alpha = 0.5), 2, as.list), do.call, what = rgb)))
On Thu, Mar 31, 2011 at 2:52 PM, Frostygoat <frostyg...@gmail.com> wrote: > Is there a grayscale equivalent to alpha levels in rgb? > > Example: I have the following to make red transparent circles overlap > with previously plotted blue symbols. > > symbols(x=sites$long,y=sites$lat,circles=log(sites$prop.nem > +1),add=T,inches=F,bg=rgb(red=1,green=0,blue=0, > alpha=0.5),fg=rgb(red=1,green=0,blue=0, alpha=0.5)) > > I'm having a hard time coming up with a grayscale equivalent. > > Thanks! > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > -- Henrique Dallazuanna Curitiba-Paraná-Brasil 25° 25' 40" S 49° 16' 22" O ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
