simpleTheme             package:lattice             R Documentation

Function to generate a simple theme

Description:

     Simple interface to generate a list appropriate as a theme,
     typically used as the 'par.settings' argument in a high level call

Usage:

     simpleTheme(col, alpha, 
                 cex, pch, lty, lwd, font, fill, border,
                 col.points, col.line, 
                 alpha.points, alpha.line)

Arguments:

col, col.points, col.line: A color specification.  'col' is used for
          components 'plot.symbol', 'plot.line', 'plot.polygon',
          'superpose.symbol', 'superpose.line', and
          'superpose.polygon'.  'col.points' overrides 'col', and is
          used only for 'plot.symbol' and 'superpose.symbol'. 
          Similarly, 'col.lines' overrides 'col' for 'plot.line' and
          'superpose.line'.  The arguments can be vectors, but only the
          first component is used for scalar targets (i.e., the ones
          without '"superpose"' in their name). 

alpha, alpha.points, alpha.line: A numeric alpha transparency
          specification.  The same rules as 'col', etc., apply. 

cex, pch, font: Parameters for points.  Applicable for components
          'plot.symbol' (for which only the first component is used)
          and 'superpose.symbol' (for which the arguments can be
          vectors). 

lty, lwd: Parameters for lines.  Applicable for components 'plot.line'
          (for which only the first component is used) and
          'superpose.line' (for which the arguments can be vectors). 

    fill: fill color, applicable for components 'plot.symbol',
          'plot.polygon', 'superpose.symbol', and 'superpose.polygon'.  

  border: border color, applicable for components 'plot.polygon' and
          'superpose.polygon'.  

Details:

     The appearance of a lattice display depends partly on the "theme"
     active when the display is plotted (see 'trellis.device' for
     details).  This theme is used to obtain defaults for various
     graphical parameters, and in particular, the 'auto.key' argument
     works on the premise that the same source is used for both the
     actual graphical encoding and the legend.  The easiest way to
     specify custom settings for a particular display is to use the
     'par.settings' argument, which is usually tedious to construct as
     it is a nested list.  The 'simpleTheme' function can be used in
     such situations as a wrapper that generates a suitable list given
     parameters in simple 'name=value' form, with the nesting made
     implicit.  This is less flexible, but straightforward and
     sufficient in most situations.

Value:

     A list that would work as the 'theme' argument to 'trellis.device'
     and 'trellis.par.set', or as the 'par.settings' argument to any
     high level lattice function such as 'xyplot'.

Author(s):

     Deepayan Sarkar Deepayan.Sarkar@R-project.org, based on a
     suggestion from John Maindonald.

See Also:

     'trellis.device', 'xyplot', 'Lattice'

Examples:

     str(simpleTheme(pch = 16))

     dotplot(variety ~ yield | site, data = barley, groups = year,
             auto.key = list(space = "right"),
             par.settings = simpleTheme(pch = 16),
             xlab = "Barley Yield (bushels/acre) ",
             aspect=0.5, layout = c(1,6))

