Querying the Viewport Tree: 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

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

all

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

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

Details

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

Examples

Run this code

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)