Function to generate a simple theme

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, but is used only for "plot.symbol" and "superpose.symbol". Similarly, col.line 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

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

Examples


str(simpleTheme(pch = 16))
#> List of 6
#>  $ plot.symbol      :List of 1
#>   ..$ pch: num 16
#>  $ plot.line        : list()
#>  $ plot.polygon     : list()
#>  $ superpose.symbol :List of 1
#>   ..$ pch: num 16
#>  $ superpose.line   : list()
#>  $ superpose.polygon: list()

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))