grid.grob                package:grid                R Documentation

Create a Grid Graphical Object

Description:

     These functions create grid graphical objects.

Usage:

     grid.grob(list.struct, cl = NULL, draw = TRUE)
     grob(..., name = NULL, gp = NULL, vp = NULL, cl = NULL) 
     gTree(..., name = NULL, gp = NULL, vp = NULL, children = NULL, 
           childrenvp = NULL, cl = NULL)
     grobTree(..., name = NULL, gp = NULL, vp = NULL, 
              childrenvp = NULL, cl = NULL)
     childNames(gTree)
     gList(...)

Arguments:

     ...: For 'grob' and 'gTree', the named slots describing important
          features of the graphical object. For 'gList' and 'grobTree',
          a series of grob objects. 

list.struct: A list (preferably with each element named).

    name: A character identifier for the grob.  Used to find the grob
          on the display list and/or as a child of another grob. 

children: A gList object. 

childrenvp: A viewport object (or 'NULL').

      gp: A gpar object, typically the output from a call to the
          function 'gpar'.  This is basically a list of graphical
          parameter settings.

      vp: A viewport object (or 'NULL').

      cl: A string giving the class attribute for the 'list.struct'

    draw: A logical value to indicate whether to produce graphical
          output.

   gTree: A gTree object.

Details:

     These functions can be used to create a basic grob, gTree, or
     gList object, or a new class derived from one of these.

     A grid graphical object (grob) is a description of a graphical
     item.  These basic classes provide default behaviour for
     validating, drawing, and modifying graphical objects.  Both call
     the function 'validDetails' to check that the object returned is
     coherent.

     A gTree can have other grobs as children;  when a gTree is drawn,
     it draws all of its children.  Before drawing its children, a
     gTree pushes its childrenvp slot and then navigates back up (calls
     'upViewport') so that the children can specify their location
     within the childrenvp via a vpPath.

     Grob names need not be unique in general, but all children of a
     gTree must have different names.   A grob name can be any string,
     though it is not advisable to use the gPath separator  (currently
     '::') in grob names.

     The function 'childNames' returns the names of the grobs which are
     children of a gTree.

     All grid primitives ('grid.lines', 'grid.rect', ...) and some
     higher-level grid components (e.g., 'grid.xaxis' and 'grid.yaxis')
     are derived from these classes.

     'grobTree' is just a convenient wrapper for 'gTree' when the only
     components of the gTree are grobs (so all unnamed arguments become
     children of the gTree).

     'grid.grob' is deprecated.

Value:

     A grob object.

Author(s):

     Paul Murrell

See Also:

     'grid.draw', 'grid.edit', 'grid.get'.

