locator                 package:base                 R Documentation

Graphical Input

Description:

     Reads the position of the graphics cursor when the (first) mouse
     button is pressed.

Usage:

     locator(n = 512, type = "n", ...)

Arguments:

       n: the maximum number of points to locate.

    type: One of `"n"', `"p"', `"l"' or `"o"'. If `"p"' or `"o"' the
          points are plotted; if `"l"'  or `"o"' they are joined by
          lines.

     ...: additional graphics parameters used if `type != "n"' for
          plotting the locations.

Details:

     Unless the process is terminated prematurely by the user (see
     below) at most `n' positions are determined.

     The identification process can be terminated by pressing any mouse
     button other than the first.

     The current graphics parameters apply just as if `plot.default'
     has been called with the same value of `type'. The plotting of the
     points and lines is subject to clipping, but locations outside the
     current clipping rectangle will be returned.

     If the window is resized or hidden and then exposed before the
     input  process has terminated, any lines or points drawn by
     `locator' will disappear.  These will reappear once the input
     process has  terminated and the window is resized or hidden and
     exposed again. This is because the points and lines drawn by
     `locator' are not recorded in the device's display list until the
     input process has terminated.

Value:

     A list containing `x' and `y' components which are the coordinates
     of the identified points.

See Also:

     `identify'

