Brief ggarrow update – Blog | Teun van den Brand

Photo by Timothy Huliselan on pexels

I’m not gonna spend many words when few do: I have a new update for the ggarrow R package, and these are the new features.

Setup code

library(ggarrow)
#> Loading required package: ggplot2

df <- data.frame(
  x = c(1, 3, 3, 1, 1, 2, 2, 3),
  y = c(1, 2, 2, 1, 1, 3, 3, 2),
  g = rep(LETTERS[1:4], each = 2)
)

base <- ggplot(df, aes(x, y, colour = g)) +
  geom_point(colour = "black", size = 5) +
  coord_equal() +
  theme(geom = element_geom(linewidth = 1))

Parallel arrows

You can use the sep argument to separate arrows whose path are the same (or reversed). It takes the number of millimetres to space apart co-located arrows ¹. In this example, it applies to arrows A and B.

base + geom_arrow(sep = 5, resect = 5)

Half-arrows

There are new arrowheads: arrow_head_halfwing() and arrow_head_halfline(). The direction argument control which side of the line displays them.

half_arrow <- arrow_head_halfwing(direction = -1)
base + geom_arrow(sep = 1.5, resect = 5, arrow_head = half_arrow)

Distortions

The new experimental distort argument can be used to pattern the shafts of arrows. The vignette has more details to peruse.

oscillate <- distort_sinewave()
base + geom_arrow(distort = oscillate)

That about covers it, thanks for reading!

Footnotes

The resect argument antedates this release, but can be used to detach arrows from points.↩︎