On Mon, Aug 25, 2008 at 4:47 AM, baptiste auguie <ba208 at exeter.ac.uk>
wrote:> Dear all,
>
>
> I'm routinely using lattice and ggplot2, I wish to create a lattice
theme
> that looks not too dissimilar to ggplot's defaults so I can include
both
> graphs in a document with a consistent look.
>
> To illustrate my questions, consider the following example:
>
>> library(ggplot2)
>> library(lattice)
>>
>> # example data
>> x <- seq(0, 10, len = 100)
>> y1 <- jitter(sin(x), 1000)
>> y2 <- 0.5*jitter(cos(x), 1000)
>>
>> df <- melt( data.frame(x=x, one=y1, two=y2,
condition1=factor(c("a",
>> "b")), condition2=factor(c("1","1",
"2", "2"))),
>> id=c("x", "condition1",
"condition2"))
>>
>> # custom colors
>> myColors <- c( "#E41A1C", "#377EB8")
>>
>> # here is the ggplot2 version
>> p <- qplot(x,value, data=df, facets = condition1 ~ condition2,
>> colour=variable)
>> p <- p + scale_colour_manual(values = myColors)
>> print(p)
>>
>> # lattice version
>> lattice.options(default.theme = canonical.theme(color = T))
>> trellis.par.set("strip.border" = list(col="white"))
>> trellis.par.set("background" = list(col="white"))
>> trellis.par.set("axis.line" = list(col="darkgrey"))
>> trellis.par.set("strip.background" =
list(col="darkgrey"))
>> trellis.par.set("plot.symbol" = list(col = myColors, pch=16,
cex=0.8))
>>
>>
>> p2 <- xyplot(value ~ x | condition1 + condition2, data=df, groups
>> variable,
>> strip=strip.custom(which.given=1),
>> strip.left=strip.custom(which.given=2) ,
>> panel = function(x, y, ...) {
>> panel.fill(grey(0.95), border="white")
>> panel.grid(h=-1, v=-1, col="white",
col.line="white",
>> lty=1, lwd=2.5)
>> lpoints(x, y, pch=16, col=1:2, cex=1)
>> },
>> key = simpleKey(levels(df$variable), space = "right"))
>>
>> print(p2)
>
> Several things resist me, I welcome any input,
>
> - with two levels of facetting, i often find convenient to layout the
graphs
> in a 2d, rectangular matrix, and have vertical and horizontal strips as in
> ggplot2. Using strip and strip.left as in the example above leaves some
> blanks where the other strip is expected. Can this be tuned?
Yes; the simplest solution is to use the useOuterStrips() function
from latticeExtra.
> - in addition to the main grid, I'd like to set a finer, secondary
grid,
> that subdivides it in halves. I can't find how to do this using
panel.grid
If you mean automatically, then panel.grid() allows you to specify the
'n' parameter to pretty(). This works for the x-axis in your example
(see below), but not the y-axis. For finer control, you need to
specify the locations explicitly (probably using panel.abline).
> - the axes should be white, but trellis.par.set("axis.line" >
list(col="white")) removes the tick marks altogether. Is there a way
to get
> rid off the line but keep the tick marks? There is a new setting for this
in
> base graphics, I guess there must be one in lattice with an appropriate
call
> to grid?
There probably should be one (maybe called "axis.tick"), but there
isn't yet. A workaround is to use scales$col (see below).
> - to clip the background color to the plotting region as opposed to the
> whole page, I use panel.fill, maybe there's a better way (a setting
outside
> the plotting function)?
Not really. You could change the default panel function if you want.
Here's a modified version of your example:
# lattice version
lattice.options(default.theme = canonical.theme(color = T))
trellis.par.set("strip.border" = list(col="white"))
trellis.par.set("background" = list(col="white"))
trellis.par.set("axis.line" = list(col="white"))
trellis.par.set("strip.background" = list(col="darkgrey"))
trellis.par.set("superpose.symbol" = list(col = myColors, pch=16,
cex=0.8))
library(latticeExtra)
p2 <-
xyplot(value ~ x | condition2 + condition1,
data=df, groups = variable,
panel = function(x, y, ...) {
panel.fill(grey(0.95), border="white")
panel.grid(h=-10, v=-10,
col="white",
lty=1, lwd=1)
panel.grid(h=-5, v=-5,
col="white",
lty=1, lwd=2.5)
panel.superpose(x, y, ...)
},
as.table = TRUE,
between = list(x = 0.1, y = 0.1),
scales = list(col = "darkgrey"),
auto.key list(space = "right", title =
"variable"))
print(useOuterStrips(p2))
-Deepayan