R help - Jun 2007 - Changing graphics height when using grid and lattice

Hi,

I have recently been playing with the grid package in an attempt to create
some pages containing multiple lattice plots on the same page. However, when
I specify a grid layout with different widths, such as:

pushViewport(viewport(layout = grid.layout(1, 2, unit(c(2, 1),
"null"))))

the individual graphs do not end up as the same height - which is a feature
I would prefer to have. 

A complete example is as follows:

### Start of example

library(lattice)
library(Hmisc)
library(grid)


# Incidence data
testData <- data.frame(
	strata = rep(c("CHF : Yes", "CHF : No"), each = 20),
	ae = rep(paste("Adverse Event", 1:10), each = 2),
	trt = rep(c("Active", "Placebo"), 20),
	pct = runif(40, 1, 30)
)

# RR data
testData2 <- data.frame(
	strata = rep(c("CHF : Yes", "CHF : No"), each = 10),
	ae = paste("Adverse Event", 1:10),
	rr = runif(20, 0.5, 5)
)
testData2$lower = testData2$rr / 2
testData2$upper = testData2$rr * 2
	

# Combined plot
testPlots <- function(relativeWidth)
{

plot1<- dotplot(
	ae ~ pct | strata, 
	groups = trt, 
	data = testData,  
	layout = c(1, 2),
	xlab = "Percent",
	auto.key = list(space = "top", columns = 2)
)


plot2 <- Dotplot(
	ae ~ Cbind(rr, log10(lower), log10(upper)) | strata,
	data = testData2,
	panel = function(...)
	{
		panel.Dotplot(...)
		panel.abline(v = 0, col = 'red', lty = 2)
	},
	layout = c(1, 2), 
	scales = list(
		x = list(log = T, at = c(0.125, 0.25, 0.5, 1, 2, 4, 8, 16, 32)),
		y = list(draw = F)
	),
	xlab = "Relative Risk with 95% CI",
	ylab = "",
	key = list(text = list(""))
)


grid.newpage()

pushViewport(viewport(layout = grid.layout(2, 1, heights = unit(c(1, 6),
"null"))))

pushViewport(viewport(layout.pos.col = 1, layout.pos.row = 1))
grid.text("Analysis of Relative Risks of various Adverse Events")
upViewport()

pushViewport(viewport(layout.pos.col = 1, layout.pos.row = 2))


### Change the relative width of the 2 presented graphics
pushViewport(viewport(layout = grid.layout(1, 2, unit(c(relativeWidth, 1),
"null"))))

pushViewport(viewport(layout.pos.col = 1, layout.pos.row = 1))
print(plot1, newpage = F)
upViewport()

pushViewport(viewport(layout.pos.col = 2, layout.pos.row = 1))
print(plot2, newpage = F)
upViewport()

}


# Everything is fine, both graphs maintain the same y-axis
testPlots(1)

# The second graph is now "taller" than the first one
win.graph()
testPlots(3)

##### End of example

I've been through the documentation of both lattice and grid, and I have not
been able to find the answer. I would appreciate any solution!

Regards,

James Price.
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Sent from the R help mailing list archive at Nabble.com.

On 6/28/07, Jim Price <price_ja at hotmail.com>
wrote:
>
> Hi,
>
> I have recently been playing with the grid package in an attempt to create
> some pages containing multiple lattice plots on the same page. However,
when
> I specify a grid layout with different widths, such as:
>
> pushViewport(viewport(layout = grid.layout(1, 2, unit(c(2, 1),
"null"))))
>
> the individual graphs do not end up as the same height - which is a feature
> I would prefer to have.
The default "padding" between components of a graph is defined as a
proportion of the plot area. In particular, it's unit(0.01,
"snpc"),
which makes it the same on both axes. The problem is that when you
have two grid viewports, unit(0.01, "snpc") may give different
physical length.

One option is to set all paddings to 0, which can be done with

myLatticeSettings <- function()
    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),
         layout.widths          list(left.padding = 0,
              key.ylab.padding = 0,
              ylab.axis.padding = 0,
              axis.key.padding = 0,
              right.padding = 0)
         )

trellis.par.set(myLatticeSettings())

This may not be what you want, so another option is to set the
paddings to something absolute; e.g.


myLatticeOptions <- function()
    list(layout.heights          list(top.padding = list(x = 1, units =
"mm", data = NULL),
              main.key.padding = list(x = 1, units = "mm", data =
NULL),
              key.axis.padding = list(x = 1, units = "mm", data =
NULL),
              axis.xlab.padding = list(x = 1, units = "mm", data =
NULL),
              xlab.key.padding = list(x = 1, units = "mm", data =
NULL),
              key.sub.padding = list(x = 1, units = "mm", data =
NULL),
              bottom.padding = list(x = 1, units = "mm", data =
NULL)),
         layout.widths          list(left.padding = list(x = 1, units =
"mm", data = NULL),
              key.ylab.padding = list(x = 1, units = "mm", data =
NULL),
              ylab.axis.padding = list(x = 1, units = "mm", data =
NULL),
              axis.key.padding = list(x = 1, units = "mm", data =
NULL),
              right.padding = list(x = 1, units = "mm", data = NULL))
         )

lattice.options(myLatticeOptions())

I'm not particularly attached to the "snpc" solution, so I may
change
them at some point.

-Deepayan