lattice (version 0.17-10)

print.trellis: Plot and Summarize Trellis Objects

Description

The print and plot methods produce a graph from a "trellis" object. The print method is necessary for automatic plotting. plot method is essentially an alias, provided for convenience. The summary method gives a textual summary of the object. dim and dimnames describe the cross-tabulation induced by conditioning. panel.error is the default handler used when an error occurs while executing the panel function.

Usage

## S3 method for class 'trellis':
plot(x, position, split,
      more = FALSE, newpage = TRUE,
      packet.panel = packet.panel.default, 
      draw.in = NULL,
      panel.height = lattice.getOption("layout.heights")$panel,
      panel.width = lattice.getOption("layout.widths")$panel,
      save.object = lattice.getOption("save.object"),
      panel.error = lattice.getOption("panel.error"),
      prefix,
      ...)
## S3 method for class 'trellis':
print(x, \dots)
## S3 method for class 'trellis':
summary(object, \dots)
## S3 method for class 'trellis':
dim(x)
## S3 method for class 'trellis':
dimnames(x)
panel.error(e)

Details

This is the default print method for objects of class "trellis", produced by calls to functions like xyplot, bwplot etc. It is usually called automatically when a trellis object is produced. It can also be called explicitly to control plot positioning by means of the arguments split and position.

When newpage = FALSE, the current grid viewport is treated as the plotting area, making it possible to embed a Lattice plot inside an arbitrary grid viewport. The draw.in argument provides an alternative mechanism that may be simpler to use.

The print method uses the information in x (the object to be printed) to produce a display using the Grid graphics engine. At the heart of the plot is a grid layout, of which the entries of most interest to the user are the ones containing the display panels.

Unlike in older versions of Lattice (and Grid), the grid display tree is retained after the plot is produced, making it possible to access individual viewport locations and make additions to the plot. For more details and a lattice level interface to these viewports, see trellis.focus.

See Also

Lattice, unit, update.trellis, trellis.focus, packet.panel.default

Examples

p11 <- histogram( ~ height | voice.part, data = singer, xlab="Height")
p12 <- densityplot( ~ height | voice.part, data = singer, xlab = "Height")
p2 <- histogram( ~ height, data = singer, xlab = "Height")


## simple positioning by split
print(p11, split=c(1,1,1,2), more=TRUE)
print(p2, split=c(1,2,1,2))

## Combining split and position:
print(p11, position = c(0,0,.75,.75), split=c(1,1,1,2), more=TRUE)
print(p12, position = c(0,0,.75,.75), split=c(1,2,1,2), more=TRUE)
print(p2, position = c(.5,.75,1,1), more=FALSE)

## Using seekViewport

## repeat same plot, with different polynomial fits in each panel
xyplot(Armed.Forces ~ Year, longley, index.cond = list(rep(1, 6)),
       layout = c(3, 2),
       panel = function(x, y, ...)
       {
           panel.xyplot(x, y, ...)
           fm <- lm(y ~ poly(x, panel.number()))
           llines(x, predict(fm))
       })

grid::seekViewport(trellis.vpname("panel", 1, 1))
cat("Click somewhere inside the first panel:\n")
ltext(grid::grid.locator(), lab = "linear")

grid::seekViewport(trellis.vpname("panel", 1, 1))
grid::grid.text("linear")

grid::seekViewport(trellis.vpname("panel", 2, 1))
grid::grid.text("quadratic")

grid::seekViewport(trellis.vpname("panel", 3, 1))
grid::grid.text("cubic")

grid::seekViewport(trellis.vpname("panel", 1, 2))
grid::grid.text("degree 4")

grid::seekViewport(trellis.vpname("panel", 2, 2))
grid::grid.text("degree 5")

grid::seekViewport(trellis.vpname("panel", 3, 2))
grid::grid.text("degree 6")

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