\HeaderA{arrow}{Describe arrows to add to a line.}{arrow}
\keyword{dplot}{arrow}
\begin{Description}\relax
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., \code{grid.lines}.
\end{Description}
\begin{Usage}
\begin{verbatim}
arrow(angle = 30, length = unit(0.25, "inches"),
      ends = "last", type = "open")
\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{angle}] The angle of the arrow head in degrees (smaller numbers
produce narrower, pointier arrows).  Essentially describes
the width of the arrow head.
\item[\code{length}] A unit specifying the length of the arrow head (from tip
to base).
\item[\code{ends}] One of \code{"last"}, \code{"first"}, or \code{"both"},
indicating which ends of the line to draw arrow heads.
\item[\code{type}] One of \code{"open"} or \code{"closed"} indicating
whether the arrow head should be a closed triangle.
\end{ldescription}
\end{Arguments}
\begin{Examples}
\begin{ExampleCode}
arrow()
\end{ExampleCode}
\end{Examples}

