Querying the Viewport Tree {grid}

R Documentation

Get the Current Grid Viewport (Tree)

Description

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

current.parent returns the parent of the current viewport.

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.

current.rotation returns the (total) rotation for the current viewport.

Usage

current.viewport()
current.parent(n=1)
current.vpTree(all=TRUE)
current.vpPath()
current.transform()

Arguments

n	The number of generations to go up.
all	A logical value indicating whether the entire viewport tree should be returned.

Details

It is possible to get the grandparent of the current viewport (or higher) using the n argument to current.parent().

The parent of the ROOT viewport is NULL. It is an error to request the grandparent of the ROOT viewport.

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)

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