R/g_legend.r

In SubgrPlots: Graphical Displays for Subgroup Analysis in Clinical Trials

# Function to extract legend from ggplot
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)}