convertXY              package: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)

