R: Convert between Graphics Coordinate Systems

convertXY {graphics} | R Documentation

## Convert between Graphics Coordinate Systems

### Description

Convert between graphics coordinate systems.

### Usage

    grconvertX(x, from = "user", to = "user")
    grconvertY(y, from = "user", to = "user")

### Arguments

`x, y` | numeric vector of coordinates.
`from, to` | character strings giving the coordinate systems to convert between.

### Details

The coordinate systems are

`"user"`
  user coordinates.
`"inches"`
  inches.
`"device"`
  the device coordinate system.
`"ndc"`
  normalized device coordinates.
`"nfc"`
  normalized figure coordinates.
`"npc"`
  normalized plot coordinates.
`"nic"`
  normalized inner region coordinates. (The ‘inner region’ is that inside the outer margins.)

(These names can be partially matched.) For the ‘normalized’ coordinate systems the lower left has value 0 and the top right value 1.

Device coordinates are those in which the device works: they are usually in pixels where that makes sense and in big points (1/72 inch) otherwise (e.g. `pdf` and `postscript`).

### Value

A numeric vector of the same length as the input.

### Examples

    op <- par(omd=c(0.1, 0.9, 0.1, 0.9), mfrow = c(1, 2))
    plot(1:4)
    for(tp in c("in", "dev", "ndc", "nfc", "npc", "nic"))
        print(grconvertX(c(1.0, 4.0), "user", tp))
    par(op)

[Package graphics version 2.8.1 Index]