Querying the Viewport Tree       package:grid       R Documentation

Get the Current Grid Viewport (Tree)

Description:

     'current.viewport()' returns the viewport that Grid is going to
     draw into.

     'current.vpTree' returns the entire Grid viewport tree.

     'current.vpPath' returns the viewport path to the current
     viewport.

     'current.transform' returns the transformation matrix for the
     current viewport.

Usage:

     current.viewport(vp=NULL)
     current.vpTree(all=TRUE)
     current.vpPath()
     current.transform()

Arguments:

      vp: A Grid viewport object.  Use of this argument has been
          deprecated.

     all: A logical value indicating whether the entire viewport tree
          should be returned.

Details:

     If 'all' is 'FALSE' then 'current.vpTree' only returns the subtree
     below the current viewport.

Value:

     A Grid viewport object from 'current.viewport' or
     'current.vpTree'.

     'current.transform' returns a 4x4 transformation matrix.

     The viewport path returned by 'current.vpPath' is 'NULL' if the
     current viewport is the 'ROOT' viewport

Author(s):

     Paul Murrell

See Also:

     'viewport'

Examples:

     grid.newpage()
     pushViewport(viewport(width=0.8, height=0.8, name="A"))
     pushViewport(viewport(x=0.1, width=0.3, height=0.6,
       just="left", name="B"))
     upViewport(1)
     pushViewport(viewport(x=0.5, width=0.4, height=0.8,
       just="left", name="C"))
     pushViewport(viewport(width=0.8, height=0.8, name="D"))
     current.vpPath()
     upViewport(1)
     current.vpPath()
     current.vpTree()
     current.viewport()
     current.vpTree(all=FALSE)
     popViewport(0)

