[R] gridBase and new.page() / grid.newpage()

[Peter Cowan]

Paul,

The real case is a function where I'd want to allow end users to pass
an arbitrary plotting function to be a sub plot within a larger plot
(e.g. the code that does the density plots would actually be passed as
a parameter.  I adapted my example to reflect this.   I expect most of
my end users to be unfamiliar with grid, yet familiar with base
graphics.

Thanks,

Peter

Aplot <- function(){
    par(plt = gridPLT(), new = TRUE)
    grid.rect(gp=gpar(fill="light grey"))
    dens <- density(rnorm(10))
    plot.density(dens, axes = FALSE,
        mar = c(0,0,0,0), main = "", xlab = "", ylab = "")
}

myplot <- function(subplot) {
   grid.newpage()
   plot.new()
   n <- 10
   datalayout <- grid.layout(ncol = 2, width = unit(c(1, 1/n),
c('null', 'null')))

   pushViewport(viewport(width = .8, height = .8, layout = datalayout))
   grid.rect(gp=gpar(col="grey"))

   for(i in 1:n) {
       pushViewport(viewport(
           y = i/n - 0.5 / n, x = 1,
           height = unit(1/n, 'npc'),
           width = unit(1/n, 'npc')))
           subplot()
       upViewport()
   }
   pushViewport(viewport(xscale = c(0, 1), layout.pos.col = 1))
   grid.rect(gp=gpar(fill="grey"))
   grid.points()
   upViewport()
   upViewport()
}

myplot(Aplot)
myplot(Aplot)

pdf()
myplot(Aplot)
myplot(Aplot)
dev.off()


On Sun, Aug 10, 2008 at 1:48 PM, Paul Murrell <p.murrell at auckland.ac.nz> wrote:
> Hi
>
>
> Peter Cowan wrote:
>> Hello all,
>>
>> I'm trying to write a function using the gridBase package.  I'd like
>> to push several base subplots to a larger plot constructed with grid.
>> However, I'm having trouble getting consistent results when running
>> the function when the plotting window (quartz) is closed, when it is
>> left open and the plot function is repeated to the same window, and
>> when the output is saved to a pdf, see the example below.  In the case
>> of the pdf plot pages are preceded by a blank page.  However, leaving
>> out either plot.new() or grid.newpage() each presents different
>> problems.  I looked through the R Graphics book and package vignette
>> but didn't see this particular issue addressed.
>
>
> There can be complications when both the 'graphics' package and the
> 'grid' package try to start a new page.
>
> Before trying to untangle this particular example, is it possible to
> side step the problem by drawing those density plots using a
> grid-compatible system such as either lattice or ggplot ?
>
> Or, if the "real" case is as simple as this, perhaps even just
> grid.lines() will do the job (?)
>
> Paul
>
>
>> Thanks in advance,
>>
>> Peter
>>
>> myplot <- function() {
>>     grid.newpage()
>>     plot.new()
>>     n <- 10
>>     datalayout <- grid.layout(ncol = 2, width = unit(c(1, 1/n),
>> c('null', 'null')))
>>
>>     pushViewport(viewport(width = .8, height = .8, layout = datalayout))
>>     grid.rect(gp=gpar(col="grey"))
>>
>>     for(i in 1:n) {
>>         pushViewport(viewport(
>>             y = i/n - 0.5 / n, x = 1,
>>             height = unit(1/n, 'npc'),
>>             width = unit(1/n, 'npc')))
>>             par(plt = gridPLT(), new = TRUE)
>>             grid.rect(gp=gpar(fill="light grey"))
>>             dens <- density(rnorm(10))
>>             plot.density(dens, axes = FALSE,
>>                 mar = c(0,0,0,0), main = "", xlab = "", ylab = "")
>>         upViewport()
>>     }
>>     pushViewport(viewport(xscale = c(0, 1), layout.pos.col = 1))
>>     grid.rect(gp=gpar(fill="grey"))
>>     grid.points()
>>     upViewport()
>>     upViewport()
>> }
>>
>> myplot()
>> myplot()
>>
>> pdf()
>> myplot()
>> myplot()
>> dev.off()
>>
>> ______________________________________________
>> R-help at 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.
>
> --
> Dr Paul Murrell
> Department of Statistics
> The University of Auckland
> Private Bag 92019
> Auckland
> New Zealand
> 64 9 3737599 x85392
> paul at stat.auckland.ac.nz
> http://www.stat.auckland.ac.nz/~paul/
>