Is it possible to use Arrows header style in igraph package for ggplot segments and axis lines? There are some options in grid, but these options do not yield the arrows in igraph.
library(igraph)
plot(0, 0, xlab="", ylab="", xlim=c(0,1), ylim=c(0,1))
iArrows <- igraph:::igraph.Arrows
iArrows(c(0,0,0.5), c(0,0,0.5), c(0,1,1), c(1,0,1), h.lwd=2, sh.lwd=2, width=1, size=1.5)
library(ggplot2)
qplot(0,0,xlim=c(0,1), ylim=c(0,1), xlab="", ylab="") + theme_classic() +
geom_segment(aes(x = 0.5, y = 0.5, xend = 1, yend = 1),
arrow = arrow(length = unit(0.5, "cm")))
