trellis.object: A Trellis Plot Object
Description
This class of objects is returned by high level lattice display
  functions, and is usually plotted by default by its `print' method.Value
- A trellis object, as returned by high level lattice functions like
  xyplot, is a list with the ``class'' attribute set to
  ``trellis''.  Many of the components of this list are simply the
  arguments to the high level function that produced the object.  Among
  them are:
- layout
- page
- panel
- prepanel
- main
- sub
- par.settings
- par.strip.text
- strip
- skip
- xlab
- ylab
describe
- index.condlist with index for each of the conditioning variables
- perm.condpermutation of the order of the conditioning variables
- aspect.fill
- {
      logical, whether aspectis ``fill''
    }
- aspect.rationumeric, aspect ratio to be used if- aspect.fillis- FALSE
- call
- { call that generated the object. }
- condlevels
- {
      list with levels of the conditioning variables
    }
- legend
- {
      list describing the legend(s) to be drawn
    }
- panel.argsa list as long as the number of panels, each element being a list
      itself, containing the arguments in named form to be passed to the
      panel function in that panel.
- panel.args.commona list containing the arguments common to all the panel functions
      in- name=valueform
- x.scaleslist describing x-scale, can consist of several other lists,
      paralleling panel.args, if x-relation is not ``same''
- y.scaleslist describing y-scale, similar to- x.scales
- x.betweennumeric vector of interpanel x-space
- y.betweennumeric vector of interpanel y-space
- x.limitsnumeric vector of length 2 or list, giving x-axis limits
- y.limitssimilar to- x.limits