Given several objects which are capable of being plotted,
create a list containing these objects as if they were
successive layers of a plot. The list can then be plotted
in different ways.
Usage
layered(..., plotargs = NULL)
Arguments
...
Objects which can be plotted by plot.
plotargs
Default values of the plotting arguments for each of the objects.
A list of lists of arguments of the form name=value.
Value
A list, belonging to the class "layered".
Details
Layering is a simple mechanism for controlling
a high-level plot that is composed of
several successive plots, for example, a background and a foreground
plot. The layering mechanism makes it easier to issue the plot command,
to switch on or off the plotting of each individual layer,
and to control the plotting arguments that are
passed to each layer.
Each individual layer in the plot should be saved as an object
that can be plotted using plot. It will typically belong to
some class, which has a method for the generic function plot.
The command layered simply saves the objects ...
as a list of class "layered". This list can then be plotted by
the method plot.layered. Thus, you only need to
type a single plot command to produce the multi-layered plot.
Individual layers of the plot can be switched on or off, or
manipulated, using arguments to plot.layered.
The argument plotargs contains default values of the
plotting arguments for each layer. It should be a list, with one
entry for each object in .... Each entry of plotargs
should be a list of arguments in the form name=value, which are
recognised by the plot method for the relevant layer.