Problem with viewports, print.trellis and more/newpage

Dear R-users,

I have got the following problem. I need to create 4x2 arrays of xyplot's on
several pages. The plots are created within a loop and plotted using the
print function. It seems that I cannot find the proper grid syntax with my
viewports, and the more/newpage arguments.

The following script is a simplification but hopefully will suffice to
illustrate my problem. Any suggestion from the list would be greatly
appreciated.

Sebastien

#########

library(lattice)

foo <- data.frame(x=1:10,y=1:10)

for (i in 1:4) {
?#isnewpage <- ? ? FALSE

?plots <- xyplot(y~x,data=foo)

?pushViewport(viewport(x=0,
? ? ? ? ? ? ? ? ? ? ? y=0,
? ? ? ? ? ? ? ? ? ? ? width=1,
? ? ? ? ? ? ? ? ? ? ? height=0.95,
? ? ? ? ? ? ? ? ? ? ? just=c(0,0)))

?print(plots, split=c(1,1,2,4), more=T)#, newpage=isnewpage)
?print(plots, split=c(2,1,2,4), more=T)#, newpage=isnewpage)
?print(plots, split=c(1,2,2,4), more=T)#, newpage=isnewpage)
?print(plots, split=c(2,2,2,4), more=T)#, newpage=isnewpage)
?print(plots, split=c(1,3,2,4), more=T)#, newpage=isnewpage)
?print(plots, split=c(2,3,2,4), more=T)#, newpage=isnewpage)
?print(plots, split=c(1,4,2,4), more=T)#, newpage=isnewpage)
?print(plots, split=c(2,4,2,4), more=F)#, newpage=isnewpage)
? ??popViewport()
? ??pushViewport(viewport(x=0,
? ? ? ? ? ? ? ? ? ? ? y=0.95,
? ? ? ? ? ? ? ? ? ? ? width=1,
? ? ? ? ? ? ? ? ? ? ? height=0.05,
? ? ? ? ? ? ? ? ? ? ? just=c(0,0)))
? ? grid.text(label = i,
? ? ? ? ? ? ? just = c("centre","centre"),
? ? ? ? ? ? ? gp = gpar(fontsize = 10, font = 2))
? ? popViewport()
? ??# Updates isnewpage
?# isnewpage <- TRUE
}
--
*Sebastien Bihorel, PharmD, PhD*
PKPD Scientist
Cognigen Corp
Email: sebastien.bihorel at cognigencorp.com
<mailto:sebastien.bihorel at cognigencorp.com>
Phone: (716) 633-3463 ext. 323