Graph flow chart of transition from states

Question

I\'m trying to find a way to graph something like this in R:

It is a tr

Answer 1

My answer is just a proof of concept to demonstrate the feasibility of this plot using grid and bezier. I use lattice to plot the scene and then grid package in the native. It is just a start, I think you can easily complete it.

library(grid)
library(lattice)

dat <- data.frame(x=c(1,1,2,2),
                  y=c(1,2,1,2),
                  weight=c(2,1,1,2),
                  text=c('B','A','B','A'))
cols <- colorRampPalette(c("grey", "green"))(nrow(dat))
xyplot(y~x,data=dat,groups=weight,
       xlim=extendrange(dat$x,f=1),
       ylim=extendrange(dat$y,f=1),
       panel=function(x,y,groups,...){
         lapply(seq_along(x),function(i){
         grid.roundrect(x[i],y[i],
                        width=.5, 
                        height=.5*groups[i],
                        gp=gpar(fill=cols[i],lwd=5,col='blue'),
                        def='native')
         grid.text(x[i],y[i],label=dat$text[i],
                    gp=gpar(cex=5,col='white'),
                   def='native')
        })
         xx <- c(x[1]+0.25, x[1]+0.25, x[3]-0.25, x[3]-0.25)
         yy <- c(y[1], y[1], y[3], y[3])
         grid.bezier(xx, yy,
                     gp=gpar(lwd=3, fill="black"),
                     arrow=arrow(type="closed"),
                     def='native')
         xx <- c(x[1]+0.25, 1, 2, x[4]-0.25)
         yy <- c(y[1], 2, 1, y[4])
         grid.bezier(xx, yy,
                     gp=gpar(lwd=3, fill="black"),
                     arrow=arrow(type="closed",
                                 length=unit(0.5, "inches")),
                     def='native')
         xx <- c(x[2]+0.25, x[2]+0.25, x[4]-0.25, x[4]-0.25)
         yy <- c(y[2], y[2], y[4], y[4])
         grid.bezier(xx, yy,
                     gp=gpar(lwd=3, fill="black"),
                     arrow=arrow(type="closed",
                                 length=unit(0.5, "inches")),
                     def='native')

         })