Create Grid Graphical Objects, aka "Grob"s
Creating grid graphical objects, short (grobs).
gTree() are the basic creators,
gList() take several grobs to build a new
## Grob Creation: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) gList(...)## Grob Properties: childNames(gTree) is.grob(x)
gTree, the named slots describing important features of the graphical object. For
grobTree, a series of grob objects.
- a character identifier for the grob. Used to find the grob on the display list and/or as a child of another grob.
- A gpar object, typically the output
from a call to the function
gpar. This is basically a list of graphical parameter settings.
- string giving the class attribute for the new class.
- An R object.
These functions can be used to create a basic
"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
and modifying graphical objects. Both
gTree() call the function
validDetails to check
that the object returned is internally coherent.
"gTree" can have other grobs as children; when a gTree is drawn, it
draws all of its children. Before drawing its children, a gTree
childrenvp slot and then navigates back up (calls
upViewport) so that the children can specify their location
childrenvp via a
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.
childNames returns the names of the grobs
which are children of a gTree.
grobTree is just a convenient wrapper for
when the only components of the gTree are grobs (so all
unnamed arguments become children of the gTree).
grid.grob function is defunct.
An R object of class
"grob", a graphical object.