ggplot2_ex

ggplot2_ex.r

#credit http://stackoverflow.com/questions/13649473/add-a-common-legend-for-combined-ggplots

require(ggplot2)
require(reshape)
require(gridExtra)

p.dat<-data.frame(step=row.names(grp.dat),grp.dat,stringsAsFactors=F)
p.dat<-melt(p.dat,id='step')
p.dat$step<-as.numeric(p.dat$step)

p<-ggplot(p.dat,aes(x=step,y=value))

p1<-p + geom_area(aes(fill=variable)) + theme(legend.position="bottom")

p2<-p + geom_area(aes(fill=variable),position='fill')

g_legend<-function(a.gplot){
  tmp <- ggplot_gtable(ggplot_build(a.gplot))
  leg <- which(sapply(tmp$grobs, function(x) x$name) == "guide-box")
  legend <- tmp$grobs[[leg]]
  return(legend)}

mylegend<-g_legend(p1)

grid.arrange(arrangeGrob(p1 + theme(legend.position="none"),
                         p2 + theme(legend.position="none"),
                         nrow=1),
             mylegend, nrow=2,heights=c(10, 1))