R: Accessing Auxiliary Information During Plotting

G_panel.number {lattice} | R Documentation

## Accessing Auxiliary Information During Plotting

### Description

Control over lattice plots are provided through a collection of user specifiable functions that perform various tasks during the plotting. Not all information is available to all functions. The functions documented here attempt to provide a consistent interface to access relevant information from within these user specified functions, namely those specified as the `panel`, `strip` and `axis` functions. Note that this information is not available to the `prepanel` function, which is executed prior to the actual plotting.

### Usage

    current.row(prefix)
    current.column(prefix)
    panel.number(prefix)
    packet.number(prefix)
    which.packet(prefix)

    trellis.currentLayout(which = c("packet", "panel"), prefix)

### Arguments

`which` | whether return value (a matrix) should contain panel numbers or packet numbers, which are usually, but not necessarily, the same (see below for details).
`prefix` | A character string acting as a prefix identifying the plot of a `"trellis"` object. Only relevant when a particular page is occupied by more than one plot. Defaults to the value appropriate for the last `"trellis"` object printed. See `trellis.focus`.

### Value

`trellis.currentLayout` returns a matrix with as many rows and columns as in the layout of panels in the current plot. Entries in the matrix are integer indices indicating which packet (or panel; see below) occupies that position, with 0 indicating the absence of a panel. `current.row` and `current.column` return integer indices specifying which row and column in the layout are currently active. `panel.number` returns an integer counting which panel is being drawn (starting from 1 for the first panel, a.k.a. the panel order). `packet.number` gives the packet number according to the packet order, which is determined by varying the first conditioning variable the fastest, then the second, and so on. `which.packet` returns the combination of levels of the conditioning variables in the form of a numeric vector as long as the number of conditioning variables, with each element an integer indexing the levels of the corresponding variable.

### Note

The availability of these functions make redundant some features available in earlier versions of lattice, namely optional arguments called `panel.number` and `packet.number` that were made available to `panel` and `strip`. If you have written such functions, it should be enough to replace instances of `panel.number` and `packet.number` by the corresponding function calls. You should also remove `panel.number` and `packet.number` from the argument list of your function to avoid a warning.

If these accessor functions are not enough for your needs, feel free to contact the maintainer and ask for more.

### Author(s)

Deepayan Sarkar Deepayan.Sarkar@R-project.org

### See Also

`Lattice`, `xyplot`

[Package lattice version 0.20-29 Index]