R help - Jul 2003 - line colors in lattice.xyplot with png device.

Hi,

R is very new for me, so excuse if my questions are too basic...

	BTW, are there any forum  where new R users could get help without 
	annoying this huge mailing list ?
	
	
In following code, I'd like to choose the color for each of the curve
diplayed.

png(filename = filename, width = 950, height = 600, pointsize = 10,  bg
"white")
xyplot(HITS+MS1*3+FREQ~TIME   |SERVER*LOCAL, data=myd,allow.multiple = TRUE,
scales = "same", type="l")
dev.off()

another problem is that I don't get a white backgroud, which is quite
problematic when printing the output.
(I works on WIN2K)


and last but not least, is there a way to use 2 different y axis, i.e. curve
1& 2 => left axis, curve 3 => right axis ?


Sample codes would be welcome as I'm not yet used with the R syntax


Thanks,

Marc Mamin

for the background try: 

# open a trellis device. If not open the next step will not work
trellis.device(device=windows) #x11 in linux

# set background to white. Only works on an open trellis device
background<-trellis.par.get("background")
background$col<-"white"
trellis.par.set("background",background)

# set the default line colour to black
plot.line<-trellis.par.get("plot.line")
plot.line$col<-"black"
trellis.par.set("plot.line",plot.line)

# set the default symbol colour to black
dot.symbol<-trellis.par.get("dot.symbol")
dot.symbol$col<-"black"
trellis.par.set("dot.symbol",dot.symbol)

# set strip background color
strip.background<-trellis.par.get("strip.background")
strip.background$col<-"white"
trellis.par.set("strip.background",strip.background)

should be self explanatory

try ?par to get na idea on how to get different colours for the line. the
lattice/trellis manual is avalable in pdf from bell labs

FC


========================
Federico C.F. Calboli

Department of Biology
University College London
Room 327
Darwin Building
Gower Street
London
WClE 6BT

Tel: (+44) 020 7679 4395 
Fax (+44) 020 7679 7096
f.calboli at ucl.ac.uk

here is the solution:



col<-c("#cc0000", "#330099",
"#66cc00","#ff6600" ,"#ff00cc",
"#00000",
"#bo7080", "#7080bo")
lty<-c(1,1,1,1,1,1,1,1)
lwd<-c(1,1,1,1,1,1,1,1)
mylines<-list(col=col,lty=lty,lwd=lwd)

filename<- "c:\\temp\\test.png"
trellis.device(png,filename = filename, width = 940, height = 600, pointsize
= 10,  bg = "white")

trellis.par.set("superpose.line",mylines)

xyplot(HITS+FREQ~TIME   |SERVER*LOCAL, data=subset(myd,
TYPE=="xxx"),allow.multiple = TRUE, scales = "same", 
type="l",xlim=range(myd$TIME), ylim=c(0,80000),layout=c(3,2),
key = list(lines = Rows(trellis.par.get("superpose.line"),
      c(1:2)), 
      text = list(lab=c("total hits", "hits per day")),
      columns = 2),
dev.off()




Thanks to Andy Liaw and Federico C.F. Calboli


Marc Mamin