trellis.device            package:lattice            R Documentation

Initializing Trellis Displays

Description:

     'trellis.device' initializes a Trellis display device with
     appropriate settings of the graphics control parameter
     'trellis.settings'.

Usage:

     trellis.device(device = getOption("device"),
                    color = !(dev.name == "postscript"),
                    theme = getOption("lattice.theme"),
                    bg = NULL,
                    new = TRUE,
                    retain = FALSE,
                    ...)
     canonical.theme(name, color)

Arguments:

  device: name of a function (possibly as a character string) that
          initializes a device. Admissible values include "x11",
          "windows", "mac", "postscript", "pdf", "png", etc. 

   color: logical, whether the display should be color or black and
          white. 'FALSE' for postscript devices, 'TRUE' otherwise. 

   theme: list of components that change the settings of the device
          opened, or, a function that when called produces such a list.
          The function name can be supplied as a quoted string.

          A possible use of this argument is to change the default
          settings at session startup, for example by setting
          'options(lattice.theme = "col.whitebg")'. If 'theme' is a
          function, it will not be supplied any arguments, however, it
          is guaranteed that a device will already be open when it is
          called, so one may use '.Device' inside the function to
          ascertain what device has been opened. 

      bg: background color for the device.

     new: logical flag indicating whether a new device should be
          started. If 'FALSE',  the options for the current device are
          changed to the defaults determined by the other arguments. 

  retain: logical. If 'TRUE' and a setting for this device already
          exists, then that is used instead of the defaults for this
          device. By default, pre-existing settings are overwritten
          (and lost). 

    name: name of the device for which the setting is required, as
          returned by '.Device' 

     ...: additional parameters to be passed to the 'device' function,
          most commonly 'file' for non-screen devices. 

Details:

     'trellis.device' calls the 'device' function to start a display,
     and sets an appropriate component of the variable 'lattice.theme'
     (in an unexported environment named '.LatticeEnv') to appropriate
     (device-specific) values.

     The device specific settings are determined by 'canonical.theme'
     which returns a list (see below).

     The settings can subsequently be handled by the interface
     functions 'trellis.par.get', 'trellis.par.set' and 'lset'

Value:

     'canonical.theme' returns a list of components defining graphical
     parameter settings for Lattice displays. It is used internally in
     'trellis.device', and can also be used as an argument to 'lset',
     or even as 'theme' in 'trellis.device' to use the defaults for
     another device.

Author(s):

     Deepayan Sarkar deepayan@stat.wisc.edu

See Also:

     'trellis.par.set', 'lset',  'postscript','x11', 'Lattice'

