grps <- rbind(c("low0","low6","1"),
      c("high0","low6","2"),
      c("low0","high6","3"),
      c("high0","high6","4"))

tmes <- c(48,62,55,323)

tbl <- data.frame(grps,tmes)

colnames(tbl) <- c("t1","t2","grp","n")

library(ggalluvial)

cls <- viridisLite::turbo(4,direction=-1)

cls
stRoke::color_plot(viridisLite::turbo(4,direction=-1))

p <- ggplot(tbl,aes(y = n, axis1 = t1, axis2 = t2)) +
  geom_alluvium(
    aes(fill = grp, color = grp),
    width = 1 / 16,
    alpha = .6,
    knot.pos = 0.4
  ) +
  # geom_stratum(aes(size=10),width = 1 / 4,
  #              fill = box,
  #              color = border) +
  # geom_text(stat = "stratum", aes(label = after_stat(stratum)), colour = "white", size = 20) +
  scale_x_continuous(breaks = 1:2,
                     labels = c("Pre-stroke\nquartile", "Six months\nquartile"))     +
  scale_y_continuous(breaks=c(0,103,488))+
  scale_fill_manual(values  = cls) +
  scale_color_manual(values = cls) +
  # labs(title=NULL, legend=NULL)+
  theme_minimal()

png(
  filename = "sankey_change_WSC.png",
  units = "mm",
  width = 500,
  height = 500,
  pointsize = 15,
  res = 300
); p+
  theme_minimal() +
  theme(
    legend.position = "none",
    panel.grid.major = element_blank(),
    panel.grid.minor = element_blank(),
    axis.text.y = element_blank(),
    axis.title.y = element_blank(),
    axis.text.x = element_blank(),
    plot.title = element_blank(),
    panel.background = element_rect(fill='transparent'), 
    plot.background = element_rect(fill='transparent', color=NA)
  ); dev.off()