\Header{locator}{Graphical Input}
\keyword{iplot}{locator}
\begin{Usage}
\begin{verbatim}
locator(n=512)
\end{verbatim}
\end{Usage}
\begin{Description}
\texttt{locator} reads the position of the graphics cursor when
the (first) mouse button is pressed.  Unless the process
is terminated prematurely by the user (see below) at most
\texttt{n} positions are determined.

The input process can be terminated prematurely by
pressing any mouse button other than the first,
or by clicking outside the graphics window.\end{Description}
\begin{Value}
A list containing \texttt{x} and \texttt{y} components which are
the coordinates of the identified points.\end{Value}

