Hi,

I also want to show user's name at the lower-left corner. So I added one
more line to Deepayan's code but it didn't work. I am not sure how to use
the "page" argument here. Appreciate any comment.

lattice.options(default.args = list(page = function(n) {
   panel.text(lab = sprintf("%s", date()), x = 0.99, y = 0.02, adj = 1)
   panel.text(lab = sprintf("%s", paste("User:",Sys.getenv("USERNAME"))), x
= 0.01, y = 0.02)
}))


Jun

On Fri, Apr 23, 2010 at 10:32 AM, Deepayan Sarkar <deepayan.sarkar@gmail.com
> wrote:

> On Wed, Apr 21, 2010 at 4:02 PM, David Winsemius <dwinsemius@comcast.net>
> wrote:
> >
> > On Apr 21, 2010, at 6:58 PM, David Winsemius wrote:
> >
> >> Sarkar offers a worked example of taking user input regarding location
> for
> >> locating a grid viewport outside the plot area.
> >>
> >> http://lmdvr.r-forge.r-project.org/figures/figures.html
> >>
> >> See Figure 12.1
> >>
> >> state <- data.frame(state.x77, state.region)
> >> trellis.vpname("xlab", prefix = "plot1")
> >> trellis.vpname("strip", column = 2, row = 2, prefix = "plot2")
> >>
> >>
> >> data(Chem97, package = "mlmRev")
> >> qqmath(~ gcsescore | factor(score), Chem97, groups = gender,
> >>      f.value = function(n) ppoints(100),
> >>      aspect = "xy",
> >>      page = function(n) {
> >>          cat("Click on plot to place legend", fill = TRUE)
> >>          ll <- grid.locator(unit = "npc")
> >>          if (!is.null(ll))
> >>              draw.key(simpleKey(levels(factor(Chem97$gender))),
> >>                       vp = viewport(x = ll$x, y = ll$y),
> >>                       draw = TRUE)
> >>      })
> >>
> >
> > Furthermore when I try:
> >
> > mtext(date(), side=3, line=4, adj=0)
> >
> > .... I get a datetime stamp even though I am mixing graphic paradigms.
> This
> > would seem to be one of those instances where you needn't worry about
> > getting the internal coordinates to match up.
>
> Appearances can be deceiving. Try to create a PDF file with this, and
> you will get
>
> > pdf()
> > xyplot(1 ~ 1)
> > mtext(date(), side=1, line=4, adj=0)
> Error in mtext(date(), side = 1, line = 4, adj = 0) :
>  plot.new has not been called yet
> > dev.off()
>
> Try to copy the screen device to PDF, and you will get
>
> > dev.copy(pdf, file = "/tmp/foo.pdf")
> Error in dev.copy(pdf, file = "/tmp/foo.pdf") : invalid graphics state
>
> For a footnote in lattice plots, page is the appropriate argument to
> use. Adapting an example from the book (section 9.3), the following
> will add a timestamp to all subsequent lattice plots:
>
> lattice.options(default.args = list(page = function(n) {
>    panel.text(lab = sprintf("%s", date()), x = 0.99, y = 0.05, adj = 1)
> }))
>
> xyplot(1 ~ 1)
>
>
> -Deepayan
>

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