[R] adding line to spinogram

[Prof Brian Ripley]

Package vcd is built on grid, not base graphics.

On Mon, 15 May 2006, Viktor Tron wrote:

> Dear all,
> I wonder what's special about spinograms {vcd} that prevents me from using
> it the way I do with other plots.
>
> I do:
>
>> spine(f.speaker.identity ~ x.log.lengthening,
>> data=ms,breaks=45,gp=gpar(fill=c("red","green")),xlab="length difference
>> (log ms)",ylab="speaker")
>> curve(0*x,add=T)
> Error in plot.xy(xy.coords(x, y), type = type, col = col, lty = lty, ...) :
> 	plot.new has not been called yet
>
>
> OK, if I do
>> curve(0*x,add=)
>> spine(f.speaker.identity ~ x.log.lengthening,
>> data=ms,breaks=45,gp=gpar(fill=c("red","green")),xlab="length difference
>> (log ms)",ylab="speaker")
>> curve(0*x,add=T)
>
> then the plot is what I want, but note that I had to use y=0 to get the
> line put at 0.5!!!! so it is already suspicious.
> But then:
>
>> dev.print(pdf,"mde_speakerration_by_lengthening.pdf")
> Error in dev.copy(device = function (file = ifelse(onefile, "Rplots.pdf",
> :
> 	invalid graphics state
>
> Can anyone suggest a remedy?

Use grid primitives to add to the plot.

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
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