[R] parallel rotated strips with color gradient

[Paul Murrell]

Hi


Kexin Ji wrote:
> Hi,
> I want to produce two parallel rotated strips with color gradient. So  
> far, the sample strip is something produced by this:
> 
> pushViewport(viewport(x = unit(0.638, "npc"), y =unit(0.386, "npc"),  
> width=.62, height=0.006, angle=137.2))
> grid.rect(y=100:1/100, just="top",
>           gp=gpar(col=NA,
>                   fill=colorRampPalette(c("lightgray", "white"),
>                                         space="Lab")(200)))
> 
> I want a same one parallel to it to the right.


This should at least run for you ...

# Come back out of original viewport
popViewport()
# Push new viewport alongside
pushViewport(viewport(x = unit(0.648, "npc"), y=unit(0.386, "npc"),
                       width=unit(.62 , "npc"), height=unit(0.006, "npc"),
                       angle=137.2))

grid.rect(y=100:1/100, just="top",
           gp=gpar(col=NA,
                   fill=colorRampPalette(c("lightgray", "white"),
                                         space="Lab")(200)))

popViewport()

... but that still might not look like what you want;  you might want to 
use just one viewport and draw each set of rectangles in half the height 
of the viewport.

Paul


> I've tried something like:
> 
> pushViewport(viewport(x = unit(c(0.638, 0.648), "npc"), y  
> =unit(c(0.386, 0.386), "npc"), width=unit(c(.62, .62) , "npc"),  
> height=unit(c(0.006, 0.006), "npc"),  angle=137.2, layout  
> =grid.layout(1,2)))
> 
> grid.rect(y=100:1/100, just="top",
>           gp=gpar(col=NA,
>                   fill=colorRampPalette(c("lightgray", "white"),
>                                         space="Lab")(200)))
> 
> grid.rect(y=100:1/100, just="top",
>           gp=gpar(col=NA,
>                   fill=colorRampPalette(c("lightgray", "white"),
>                                         space="Lab")(200)))
> 
> Or
> 
> vpList(pushViewport(viewport(x = 0.638, y = 0.386, width=.62,  
> height=0.006, angle=137.2)))
> 
> grid.rect(y=100:1/100, just="top",
>           gp=gpar(col=NA,
>                   fill=colorRampPalette(c("lightgray", "white"),
>                                         space="Lab")(200)))
> 
> But kept getting error messages.
> 
> Would someone please give me some hint?
> 
> Thank you very much!!
> Kexin
> 
> 
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> 
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-- 
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/