[R] curvedarrow (some graphics problem)

[baptiste auguie]

Hi,

Grid offers several functions to help drawing such graphs,

see Paul Murrell's "Can R Draw Graphs? " (useR! 2006)

I came up with this, as a quick example,

vp <-  viewport(
x = unit(0, "npc"),
y = unit(0,  "npc"),
just = c("left", "bottom"),
xscale = c(-1, 1) ,
yscale = c(-1, 1))

vp2 <-  viewport( # probably not needed but I had trouble placing the xaxis
x = unit(0, "npc"),
y = unit(0.5,  "npc"),
just = c("left", "bottom"),
xscale = c(-1, 1) ,
yscale = c(-1, 1))


 pushViewport(vp)
 grid.xaxis(at=seq(-1, 1, by=0.2), label=FALSE,  vp=vp2)
 grid.points(x=0.3, y=0.5, gp=gpar(col=NA), default.units = "npc",    
name="h1", vp=vp)
 grid.points(x=0.8, y=0.5, gp=gpar(col=NA), default.units = "npc",    
name="h2", vp=vp)
 grid.text("t", x=0.3, y=unit(-1, "line"), vp=vp2)
 grid.text("s", 0.8, unit(-1, "line"), gp=gpar(col="red"), vp=vp2)
 
 grid.curve(grobX("h2", 180),
 grobY("h2", 180),
 grobX("h1", 180),
 grobY("h1", 180),
 shape=1, ncp=10,
 square=FALSE,
 curvature=1,
 arrow=arrow())

upViewport()


HTH,

baptiste


casperyc wrote:
> Hi there,
>
> I just wonder how to draw this kind of picture...
>
> http://www.nabble.com/file/p24158796/b.jpg 
> http://www.nabble.com/file/p24158796/a.jpg 
>
> and this is what i have done
>
> %%%%%
> library(shape)
> library(diagram)
> curve(sin(x),bty="n",-8,8,yaxt="n",ylab="",xaxt="n",type="n",xlab="")
> axis(1,labels=F,at=seq(-8,8,1))
> curvedarrow(from=c(-4,-1), to=c(4,-1),curve=-0.035,arr.pos=1,lwd=1)
> text(0,-0.62,substitute(mu(s,t)))
> axis(1,labels="s",at=-4)
> axis(1,labels="t",at=4)
> %%%%%
>
> is there any easier way
> or
> the most proper  way to draw these to graphs?
>
> Thanks in advance!
>
> Chen
>