panel.axis              package: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'

