grid.grob {grid}R Documentation

Create a Grid Graphical Object


These functions create grid graphical objects.


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)


... For grob and gTree, the named slots describing important features of the graphical object. For gList, 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.


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.

grid.grob is deprecated.


A grob object.


Paul Murrell

See Also

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


[Package grid version 2.5.0 Index]