grid.segments              package:grid              R Documentation

Draw Line Segments

Description:

     These functions create and draw line segments.

Usage:

     grid.segments(x0 = unit(0, "npc"), y0 = unit(0, "npc"),
                   x1 = unit(1, "npc"), y1 = unit(1, "npc"),
                   default.units = "npc", 
                   arrow = NULL,
                   name = NULL, gp = gpar(), draw = TRUE, vp = NULL)
     segmentsGrob(x0 = unit(0, "npc"), y0 = unit(0, "npc"),
                   x1 = unit(1, "npc"), y1 = unit(1, "npc"),
                   default.units = "npc", 
                   arrow = NULL, name = NULL, gp = gpar(), vp = NULL)

Arguments:

      x0: Numeric indicating the starting x-values of the line
          segments. 

      y0: Numeric indicating the starting y-values of the line
          segments. 

      x1: Numeric indicating the stopping x-values of the line
          segments. 

      y1: Numeric indicating the stopping y-values of the line
          segments.

default.units: A string. 

   arrow: A list describing arrow heads to place at either end of the
          line segments, as produced by the 'arrow' function.

    name: A character identifier. 

      gp: An object of class 'gpar'. 

    draw: A logical value indicating whether graphics output should be
          produced.

      vp: A Grid viewport object (or NULL).

Details:

     Both functions create a segments grob (a graphical object
     describing segments), but only 'grid.segments' draws the segments
     (and then only if 'draw' is 'TRUE').

Value:

     A segments grob.  'grid.segments' returns the value invisibly.

Author(s):

     Paul Murrell

See Also:

     Grid, 'viewport', 'arrow'

