[R] line colors in lattice.xyplot with png device

[Deepayan Sarkar]

On Friday 18 July 2003 12:28, r-help-request at stat.math.ethz.ch wrote:
> Message: 9
> Date: Thu, 17 Jul 2003 13:50:29 +0200
> From: Marc Mamin <M.Mamin at intershop.de>
> Subject: [R] line colors in lattice.xyplot with png device.
> To: r-help at stat.math.ethz.ch
>
> 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()

With (simpler) simulated data:

y1 <- rnorm(50)
y2 <- rnorm(50)
x <- 1:50

xyplot(y1 + y2 ~ x, allow.m = TRUE, type = 'l', 
       col = c("red", "blue"))

There are more complicated ways, namely by changing the trellis parameter 
superpose.line (see ?trellis.par.get and ?lset).

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

Try (see ?trellis.device)

trellis.device(png, ..., bg = "white")

Also, see ?col.whitebg

> 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 ?

Not really, unless you are willing to write some complicated panel functions.

HTH,

Deepayan