# R: Panel Function for Drawing Axis Ticks and Labels

panel.axis {lattice} | R Documentation

## Panel Function for Drawing Axis Ticks and Labels

### Description

`panel.axis` is the function used by lattice to draw axes. It is typically not used by users, except those wishing to create advanced annotation. Keep in mind issues of clipping when trying to use it as part of the panel function. `current.panel.limits` can be used to retrieve a panel's x and y limits.

### Usage

    panel.axis(side = c("bottom", "left", "top", "right"),
               at,
               labels = TRUE,
               draw.labels = TRUE,
               check.overlap = FALSE,
               outside = FALSE,
               ticks = TRUE,
               half = !outside,
               which.half,
               tck = as.numeric(ticks),
               rot = if (is.logical(labels)) 0 else c(90, 0),
               text.col, text.alpha, text.cex, text.font,
               text.fontfamily, text.fontface,
               line.col, line.lty, line.lwd, line.alpha)

    current.panel.limits(unit = "native")

### Arguments

`side` | character string indicating which side axes are to be drawn on. Partial specification is allowed.
`at` | location of labels
`labels` | the labels to go along with `at`. The labels can be a character vector or a vector of expressions. Alternatively, this can be a logical. If TRUE, the labels are derived from `at`, otherwise, labels are empty.
`draw.labels` | logical indicating whether labels are to be drawn
`check.overlap` | logical, whether to check for overlapping of labels. This also has the effect of removing `at` values that are ‘too close’ to the limits.
`outside` | logical, whether to the labels draw outside the panel or inside. Note that `outside=TRUE` will only have a visible effect if clipping is disabled for the viewport (panel).
`ticks` | logical, whether to draw the tickmarks
`half` | logical, whether only half of scales will be drawn for each side
`which.half` | character string, one of `"lower"` and `"upper"`. Indicates which half is to be used for tick locations if `half=TRUE`. Defaults to whatever is suitable for `splom`
`tck` | numeric scalar, multiplier for tick length. Can be negative.
`rot` | rotation angles for labels in degrees. Can be a vector of length 2 for x- and y-axes respectively
`text.col, text.alpha, text.cex, text.font, text.fontfamily, text.fontface, line.col, line.lty, line.lwd, line.alpha` | graphical parameters
`unit` | which grid `unit` the values should be in

### Details

`panel.axis` can draw axis tick marks inside or outside a panel (more precisely, a grid viewport). It honours the (native) axis scales. Used in `panel.pairs` for `splom`, as well as for all the usual axis drawing by the print method for `"trellis"` objects. It can also be used to enhance plots ‘after the fact’ by adding axes.

### Value

`current.panel.limits` returns a list with components `xlim` and `ylim`, which are both numeric vectors of length 2, giving the scales of the current panel (viewport). The values correspond to the unit system specified by `unit`, by default `"native"`.

### Author(s)

Deepayan Sarkar Deepayan.Sarkar@R-project.org

### See Also

`Lattice`, `xyplot`, `trellis.focus`, `unit`

[Package lattice version 0.16-5 Index]