R: Null Graphical Object

grid.null {grid} | R Documentation

## Null Graphical Object

### Description

These functions create a NULL graphical object, which has zero width, zero height, and draw nothing. It can be used as a place-holder or as an invisible reference point for other drawing.

### Usage

    nullGrob(x = unit(0.5, "npc"), y = unit(0.5, "npc"),
             default.units = "npc",
             name = NULL, vp = NULL)
    grid.null(...)

### Arguments

`x` | A numeric vector or unit object specifying x-location.
`y` | A numeric vector or unit object specifying y-location.
`default.units` | A string indicating the default units to use if `x`, `y`, `width`, or `height` are only given as numeric vectors.
`name` | A character identifier.
`vp` | A Grid viewport object (or NULL).
`...` | Arguments passed to `nullGrob()`.

### Value

A null grob.

### Author(s)

Paul Murrell

### See Also

Grid, `viewport`

### Examples

    grid.newpage()
    grid.null(name="ref")
    grid.rect(height=grobHeight("ref"))
    grid.segments(0, 0, grobX("ref", 0), grobY("ref", 0))

[Package grid version 3.1.2 Index]