Thanks, I'll finaly figure it out. It was not very intuitive though, even looking at the help file. The final code, for whom it might interest is:
xyplot(Volume ~ Age|Farm, groups = Treatment, data = my_data, panel = panel.superpose, panel.groups = function(x,y, group.number, ...) { if (group.number == 1)panel.fill(col = "white") panel.grid(col = "gray",lty = 2) panel.xyplot(x,y,...) } Cristián Montes NCState University > Read ?panel.superpose carefully and pay attention to the comments about > the > group.number argument passed to panel.groups. You can test the value of > this > argument and adjust the plot accordingly. > > > > Bert Gunter > Genentech Nonclinical Statistics > 7-7374 > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > On > Behalf Of [EMAIL PROTECTED] > Sent: Friday, November 30, 2007 8:50 AM > To: r-help@r-project.org > Subject: [R] Set panel background color in a multi-group trellis plot > > Hi everyone, > > I am trying to change some of the default colors in a > multipanel-multigroup lattice graphic, but when I change the panel color > to white, the only group that is plotted is the last one, as panel.fill > overwrites all the previous ones. Is there any way to set the panel > background color for the first panel to a color and keep the rest > transparent? > > My code looks like this: > > #first set defaults for getting more distinct symbols > superp.symbol <- trellis.par.get("superpose.symbol") > superp.symbol$pch = 15:21 > superp.symbol$cex = 1.5 > trellis.par.set("superpose.symbol", superp.symbol) > > #set the default for the colors in the symbols > superp.lines <- trellis.par.get("superpose.line") > superp.lines$lty <- 1:6 > superp.lines$lwd <- 1.5 > trellis.par.set("superpose.line", superp.lines) > > #set the device color to lightblue > trellis.par.set("background", list(col = "lightblue")) > > > xyplot(Volume ~ Age|Farm, > groups = Treatment, > data = my_data, > panel = panel.superpose, > panel.groups = function(x,y, ...) > { > panel.fill(col = "white") > panel.grid(col = "gray",lty = 2) > panel.xyplot(x,y,...) > } > ______________________________________________ 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.