R help - Feb 2013 - continuous shading in plots

Hi, Can someone help me with the following?  I currently have the following
plot: plot(c(0,14,0,14),c(0,5,0,5),ann = FALSE, xaxs="i",
yaxs="i",bty="L" )
polygon(c(0,18,18), c(0,6,0), col='light grey', border = NA)
polygon(c(0,18,18), c(0,2,0), col='grey', border = NA) However, I would
like to make such a plot, but where there is a continuous shading changing fom
white to darkgrey. Can anyone give me any suggsetions how to do this in R? Thank
you, Elisabeth
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On 02/19/2013 01:20 AM, Elisabeth wever wrote:
>
>
>
>
> Hi, Can someone help me with the following?  I currently have the following
plot: plot(c(0,14,0,14),c(0,5,0,5),ann = FALSE, xaxs="i",
yaxs="i",bty="L" )
> polygon(c(0,18,18), c(0,6,0), col='light grey', border = NA)
> polygon(c(0,18,18), c(0,2,0), col='grey', border = NA) However, I
would like to make such a plot, but where there is a continuous shading changing
fom white to darkgrey. Can anyone give me any suggsetions how to do this in R?
Thank you, Elisabeth
> 	[[alternative HTML version deleted]]
>
Hi Elisabeth,
For a quick hack, try this:

segments(rep(0,100),seq(-4.5,0,length.out=200),rep(14,200),
  seq(0,4.5,length.out=200),
  col=rgb(seq(0.8,0.5,length.out=200),seq(0.8,0.5,length.out=200),
  seq(0.8,0.5,length.out=200)),lwd=2)

Jim

On 02/19/2013 09:50 AM, Jim Lemon wrote:
> Hi Elisabeth,
> For a quick hack, try this:
>
> segments(rep(0,100),seq(-4.5,0,length.out=200),rep(14,200),
> seq(0,4.5,length.out=200),
> col=rgb(seq(0.8,0.5,length.out=200),seq(0.8,0.5,length.out=200),
> seq(0.8,0.5,length.out=200)),lwd=2)
>
and even easier:

library(plotrix)
segments(rep(0,100),seq(-4.5,0,length.out=200),rep(14,200),
 
seq(0,4.5,length.out=200),col=smoothColors("white",198,"darkgray"))

Jim