These are predefined panel functions available in lattice for use in constructing new panel functions (often on-the-fly).
panel.abline(a = NULL, b = 0,
h = NULL, v = NULL,
reg = NULL, coef = NULL,
col, col.line, lty, lwd, alpha, type,
…,
reference = FALSE,
identifier = "abline")
panel.refline(…) panel.curve(expr, from, to, n = 101,
curve.type = "l",
col, lty, lwd, type,
…,
identifier = "curve")
panel.rug(x = NULL, y = NULL,
regular = TRUE,
start = if (regular) 0 else 0.97,
end = if (regular) 0.03 else 1,
x.units = rep("npc", 2),
y.units = rep("npc", 2),
col, col.line, lty, lwd, alpha,
…,
identifier = "rug")
panel.average(x, y, fun = mean, horizontal = TRUE,
lwd, lty, col, col.line, type,
…,
identifier = "linejoin")
panel.linejoin(x, y, fun = mean, horizontal = TRUE,
lwd, lty, col, col.line, type,
…,
identifier = "linejoin")
panel.fill(col, border, …, identifier = "fill")
panel.grid(h=3, v=3, col, col.line, lty, lwd, x, y, …, identifier = "grid")
panel.lmline(x, y, …, identifier = "lmline")
panel.mathdensity(dmath = dnorm, args = list(mean=0, sd=1),
n = 50, col, col.line, lwd, lty, type,
…, identifier = "mathdensity")
Variables defining the contents of the panel.
In panel.grid these are optional and are used only to choose
an appropriate method of pretty.
Coefficients of the line to be added by
panel.abline. a can be a vector of length 2,
representing the coefficients of the line to be added, in which case
b should be missing. a can also be an appropriate
‘regression’ object, i.e., an object which has a
coef method that returns a length 2 numeric vector.
The corresponding line will be plotted. The reg argument
overrides a if specified.
Coefficients of the line to be added as a vector of length 2.
A (linear) regression object, with a coef
method that gives the coefficints of the corresponding regression
line.
For panel.abline, these are numeric vectors giving
locations respectively of horizontal and vertical lines to be added
to the plot, in native coordinates.
For panel.grid, these usually specify the number of
horizontal and vertical reference lines to be added to the plot.
Alternatively, they can be negative numbers. h=-1 and
v=-1 are intended to make the grids aligned with the axis
labels. This doesn't always work; all that actually happens is that
the locations are chosen using pretty, which is also how the
label positions are chosen in the most common cases (but not for
factor variables, for instance). h and v can be
negative numbers other than -1, in which case -h and
-v (as appropriate) is supplied as the n argument to
pretty.
If x and/or y are specified in panel.grid, they
will be used to select an appropriate method for
pretty. This is particularly useful while plotting
date-time objects.
A logical flag determining whether the default
graphical parameters for panel.abline should be taken from
the “reference.line” parameter settings. The default is to
take them from the “add.line” settings. The
panel.refline function is a wrapper around
panel.abline that calls it with reference = TRUE.
An expression considered as a function of x, or a
function, to be plotted as a curve.
The number of points to use for drawing the curve.
optional lower and upper x-limits of curve. If missing, limits of current panel are used
Type of curve ("p" for points, etc), passed
to llines
A logical flag indicating whether the ‘rug’ is to be drawn on the ‘regular’ side (left / bottom) or not (right / top).
endpoints of rug segments, in normalized parent
coordinates (between 0 and 1). Defaults depend on value of
regular, and cover 3% of the panel width and height.
Character vectors, replicated to be of length two. Specifies the
(grid) units associated with start and end above.
x.units and y.units are for the rug on the x-axis and
y-axis respectively (and thus are associated with start and
end values on the y and x scales respectively).
Graphical parameters.
Usually ignored by the panel functions documented here;
the argument is present only to make sure an explicitly specified
type argument (perhaps meant for another function) does not
affect the display.
The function that will be applied to the subset of
x values (or y if horizontal is FALSE)
determined by the unique values of y (x).
A logical flag. If FALSE, the plot is
‘transposed’ in the sense that the roles of x and
y are switched; x is now the ‘factor’.
Interpretation of other arguments change accordingly. See
documentation of bwplot for a fuller explanation.
A vectorized function that produces density values given
a numeric vector named x, e.g., dnorm.
A list giving additional arguments to be passed to
dmath.
Further arguments, typically graphical parameters,
passed on to other low-level functions as appropriate. Color can
usually be specified by col, col.line, and
col.symbol, the last two overriding the first for lines and
points respectively.
A character string that is prepended to the names of grobs that are created by this panel function.
panel.abline adds a line of the form y = a + b * x, or
vertical and/or horizontal lines. Graphical parameters are obtained
from the “add.line” settings by default. panel.refline
is similar, but uses the “reference.line” settings for the
defaults.
panel.grid draws a reference grid.
panel.curve adds a curve, similar to what curve
does with add = TRUE. Graphical parameters for the curve are
obtained from the “add.line” setting.
panel.average treats one of x and y as a factor
(according to the value of horizontal), calculates fun
applied to the subsets of the other variable determined by each unique
value of the factor, and joins them by a line. Can be used in
conjunction with panel.xyplot, and more commonly with
panel.superpose to produce interaction plots.
panel.linejoin is an alias for panel.average. It is
retained for back-compatibility, and may go away in future.
panel.mathdensity plots a (usually theoretical) probability
density function. This can be useful in conjunction with
histogram and densityplot to visually assess goodness of
fit (note, however, that qqmath is more suitable for this).
panel.rug adds a rug representation of the (marginal)
data to the panel, much like rug.
panel.lmline(x, y) is equivalent to
panel.abline(lm(y ~ x)).
Lattice, panel.axis, panel.identify
identify, trellis.par.set.
# NOT RUN {
## Interaction Plot
bwplot(yield ~ site, barley, groups = year,
panel = function(x, y, groups, subscripts, ...) {
panel.grid(h = -1, v = 0)
panel.stripplot(x, y, ..., jitter.data = TRUE,
groups = groups, subscripts = subscripts)
panel.superpose(x, y, ..., panel.groups = panel.average,
groups = groups, subscripts = subscripts)
},
auto.key =
list(points = FALSE, lines = TRUE, columns = 2))
## Superposing a fitted normal density on a Histogram
histogram( ~ height | voice.part, data = singer, layout = c(2, 4),
type = "density", border = "transparent", col.line = "grey60",
xlab = "Height (inches)",
ylab = "Density Histogram\n with Normal Fit",
panel = function(x, ...) {
panel.histogram(x, ...)
panel.mathdensity(dmath = dnorm,
args = list(mean=mean(x),sd=sd(x)), ...)
} )
# }
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