Thanks much - very nice. I hadn't thought of that approach.
I dug around in the lattice source and found another way to do it so
for what it's worth, I'll post it - maybe it will be useful to
someone. Basically, I made a function from code found in
plot.trellis() that gets the grid layout for a lattice object
(layout=c(_, _) and aspect need to be specified for this to work).
Then functions getHeight() or getWidth() calculate correct height or
width for a given width or height by calculating the dimensions of all
the non-data-region parts of the plot. etc.
trellis.getlayout <- function(x,
panel.height = lattice.getOption("layout.heights")$panel,
panel.width = lattice.getOption("layout.widths")$panel
) {
if (!is.null(x$plot.args))
{
supplied <- names(x$plot.args)
if ("panel.height" %in% supplied && missing(panel.height))
panel.height <- x$plot.args$panel.height
if ("panel.width" %in% supplied && missing(panel.width))
panel.width <- x$plot.args$panel.width
}
original.condlevels <-
used.condlevels <-
lapply(x$condlevels, function(x) seq_along(x))
used.condlevels <-
mapply("[", used.condlevels, x$index.cond,
MoreArgs = list(drop = FALSE),
SIMPLIFY = FALSE)
used.condlevels <- used.condlevels[x$perm.cond]
inverse.permutation <- order(x$perm.cond) # used later
cond.max.levels <- sapply(used.condlevels, length)
number.of.cond <- length(cond.max.levels)
panel.layout <- lattice:::compute.layout(x$layout,
cond.max.levels, skip = x$skip)
if(panel.layout[1] == 0)
stop("invalid layout")
axis.text <- trellis.par.get("axis.text")
if (!x$aspect.fill)
panel.height[[1]] <- x$aspect.ratio * panel.width[[1]]
legend <- lattice:::evaluate.legend(x$legend)
xaxis.cex <-
if (is.logical(x$x.scales$cex)) rep(axis.text$cex, length = 2)
else x$x.scales$cex
xaxis.rot <-
if (is.logical(x$x.scales$rot)) c(0, 0)
else x$x.scales$rot
yaxis.cex <-
if (is.logical(x$y.scales$cex)) rep(axis.text$cex, length = 2)
else x$y.scales$cex
yaxis.rot <-
if (!is.logical(x$y.scales$rot)) x$y.scales$rot
else if (x$y.scales$relation != "same" && is.logical(x
$y.scales$labels)) c(90, 90)
else c(0, 0)
cols.per.page <- panel.layout[1]
rows.per.page <- panel.layout[2]
x.alternating <- rep(x$x.scales$alternating, length =
cols.per.page)
y.alternating <- rep(x$y.scales$alternating, length =
rows.per.page)
x.relation.same <- x$x.scales$relation == "same"
y.relation.same <- x$y.scales$relation == "same"
main <-
lattice:::grobFromLabelList(lattice:::getLabelList(x$main,
trellis.par.get("par.main.text")),
name = trellis.grobname("main"))
sub <-
lattice:::grobFromLabelList(lattice:::getLabelList(x$sub,
trellis.par.get("par.sub.text")),
name = trellis.grobname("sub"))
xlab <-
lattice:::grobFromLabelList(lattice:::getLabelList(x$xlab,
trellis.par.get("par.xlab.text"),
x$xlab.default),
name = trellis.grobname("xlab"))
ylab <-
lattice:::grobFromLabelList(lattice:::getLabelList(x$ylab,
trellis.par.get("par.ylab.text"),
x$ylab.default),
name = trellis.grobname("ylab"), orient = 90)
par.strip.text <- trellis.par.get("add.text")
par.strip.text$lines <- 1
if (!is.null(x$par.strip.text))
par.strip.text[names(x$par.strip.text)] <- x$par.strip.text
trellis.par.set(p$par.settings) # set padding, etc.
layoutCalculations <-
lattice:::calculateGridLayout(x,
rows.per.page, cols.per.page,
number.of.cond,
panel.height, panel.width,
main, sub,
xlab, ylab,
x.alternating, y.alternating,
x.relation.same, y.relation.same,
xaxis.rot, yaxis.rot,
xaxis.cex, yaxis.cex,
par.strip.text,
legend)
page.layout <- layoutCalculations$page.layout
list(lyt=page.layout, ncols=cols.per.page, nrows=rows.per.page)
}
getWidth <- function(x, height) {
require(grid)
lyt <- trellis.getlayout(x)
page.layout <- lyt$lyt
nrows <- lyt$nrows
ncols <- lyt$ncols
H <- height
h1 <- sum(unlist(lapply(page.layout$heights, function(x)
as.numeric(convertY(x, "inches")))))
w1 <- sum(unlist(lapply(page.layout$widths, function(x)
as.numeric(convertX(x, "inches")))))
w2 <- (H - h1) / (x$aspect.ratio * nrows)
W <- w1 + w2*ncols
W
}
getHeight <- function(x, width) {
require(grid)
lyt <- trellis.getlayout(x)
page.layout <- lyt$lyt
nrows <- lyt$nrows
ncols <- lyt$ncols
W <- width
h1 <- sum(unlist(lapply(page.layout$heights, function(x)
as.numeric(convertY(x, "inches")))))
w1 <- sum(unlist(lapply(page.layout$widths, function(x)
as.numeric(convertX(x, "inches")))))
h2 <- (W - w1) * x$aspect.ratio / ncols
H <- h1 + h2*nrows
H
}
# example
library(lattice)
# get rid of extra padding around plot
mypars <- list(
layout.heights = list(top.padding = 0, main.key.padding = 0,
key.axis.padding = 0, axis.xlab.padding = 0, xlab.key.padding = 0,
key.sub.padding = 0, bottom.padding = 0.5),
layout.widths = list(left.padding = 0, key.ylab.padding = 0,
ylab.axis.padding = 0, axis.key.padding = 0, right.padding = 0),
axis.components=list(top=list(pad2 = 0), right=list(pad1 = 0, pad2
= 0))
)
p <- xyplot(rnorm(100) ~ rnorm(100) | sample(c(0, 1), 100,
replace=TRUE), aspect=1.5, layout=c(2, 1),
xlab="this is some extra text\n
to show that the\n
overall aspect ratio\n
of a plot is not always\n
easily determined by\n
the aspect ratio specified for the data",
par.settings=mypars
)
pdf("a.pdf", height=6, width=getWidth(p, 6))
plot(p)
dev.off()
On Mar 9, 2010, at 10:51 PM, Felix Andrews wrote:
Basically you want to achieve an aspect ratio of 0.5 (say) when
specifying aspect = "fill". You can calculate the aspect ratio after a
lattice plot has been displayed:
currAspect <- function() {
trellis.focus("panel", 1, 1, highlight = FALSE)
sz <- current.panel.limits("mm")
trellis.unfocus()
diff(sz$y) / diff(sz$x)
}
foo <-
xyplot(rnorm(100) ~ rnorm(100), aspect="fill", ## NB "fill"
xlab="this is some extra text\n
to show that the\n
overall aspect ratio\n
of a plot is not always\n
easily determined by\n
the aspect ratio specified for the data")
dev.new(width = 10, height = 5)
print(foo)
currAspect()
#[1] 0.19003
One problem is that fonts in pdf() seem to be very different to screen
devices. You could probably work out which components of the plot have
a fixed size, and therefore work out the requried aspect ratio... but
I kinda like brute force:
aspectObjective <- function(height, width, target, ...) {
tmp <- tempfile()
pdf(tmp, width = width, height = height, ...)
print(trellis.last.object())
asp <- currAspect()
dev.off()
file.remove(tmp)
abs(asp - target)
}
print(foo)
height <- optimize(aspectObjective, c(1, 20), width = 10,
target = 0.5, tol = 0.01)$min
height
#[1] 7.6928
pdf("test.pdf", width = 10, height = height)
print(foo)
currAspect()
#[1] 0.50013
dev.off()
On 10 March 2010 07:16, Ryan Hafen <rha...@stat.purdue.edu> wrote:
I almost always supply my own aspect ratio when plotting using
lattice.
When I plot these to pdf, I would like to specify pdf dimensions
that will
result in minimal margins around the plot. In my application,
resorting to
a pdf cropper after plotting is not an option - I must do it in R.
The
problem is that I cannot determine the correct aspect ratio for the
overall
plot (accounting for strip labels, keys, titles, labels, etc.) that
would
help me determine the correct pdf dimensions. I can roughly
estimate what
the overall aspect ratio will be using the layout, etc., but this
is not
good enough. Is there a way to calculate the true overall aspect
ratio for
the entire plot?
Example: If I make a simple plot and specify aspect=0.5, you would
think
that dimensions width=10, height=5 would be a good approximation,
but for
example:
library(lattice)
pdf("plot.pdf", width=10, height=5)
xyplot(rnorm(100) ~ rnorm(100), aspect=0.5,
xlab="this is some extra text\n
to show that the\n
overall aspect ratio\n
of a plot is not always\n
easily determined by\n
the aspect ratio specified for the data")
dev.off()
doesn't work. It looks like the true aspect ratio of the resulting
non-margin area in the pdf is about 0.86. I'd like to know this in
R before
making the pdf so I can specify dimensions accordingly. Any ideas?
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--
Felix Andrews / 安福立
Postdoctoral Fellow
Integrated Catchment Assessment and Management (iCAM) Centre
Fenner School of Environment and Society [Bldg 48a]
The Australian National University
Canberra ACT 0200 Australia
M: +61 410 400 963
T: + 61 2 6125 4670
E: felix.andr...@anu.edu.au
CRICOS Provider No. 00120C
--
http://www.neurofractal.org/felix/
______________________________________________
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
