R: Describe arrows to add to a line.

This help topic is for R version 2.9.0. For the current version of R, try https://stat.ethz.ch/R-manual/R-patched/library/grid/html/arrow.html

arrow {grid}

R Documentation

Describe arrows to add to a line.

Produces a description of what arrows to add to a line. The result can be passed to a function that draws a line, e.g., grid.lines.

arrow(angle = 30, length = unit(0.25, "inches"),
      ends = "last", type = "open")

`angle`	The angle of the arrow head in degrees (smaller numbers produce narrower, pointier arrows). Essentially describes the width of the arrow head.
`length`	A unit specifying the length of the arrow head (from tip to base).
`ends`	One of `"last"`, `"first"`, or `"both"`, indicating which ends of the line to draw arrow heads.
`type`	One of `"open"` or `"closed"` indicating whether the arrow head should be a closed triangle.

arrow()