Axis labels overlapping with axis values - r

Question

I have a problem in correctly plotting the labels of the following graph:
scatterhist = function(x, y, xlab="", ylab=""){
zones=matrix(c(2,0,1,3), ncol=2, byrow=TRUE)
layout(zones, widths=c(4/5,1/5), heights=c(1/5,4/5))
xhist = hist(x, plot=F, breaks=10)
yhist = hist(y, plot=F, breaks=10)
top = max(c(xhist$counts, yhist$counts))
par(mar=c(3,3,1,1))
plot(x, y)
par(mar=c(0,3,1,1))
barplot(xhist$counts, axes=FALSE, ylim=c(0, top), space=0)
par(mar=c(3,0,1,1))
barplot(yhist$counts, axes=FALSE, xlim=c(0, top), space=0, horiz=TRUE)
par(oma=c(3,3,0,0))
mtext(xlab, side=1, line=1, outer=TRUE, adj=0,
at=.8 * (mean(x)-min(x))/(max(x)-min(x)))
mtext(ylab, side=2, line=1, outer=TRUE, adj=0,
at=.8 * (mean(y)-min(y))/(max(y)-min(y)))
}
When I type:
scatterhist(x[,6], x[,7], xlab="Cost of Taxi", ylab="Cost of Fuel")
the labels overlap with the axes values. However, if I type:
scatterhist(x[,6], x[,7], xlab="Cost of Taxi", ylab="Cost of Fuel")
scatterhist(x[,6], x[,7], xlab="Cost of Taxi", ylab="Cost of Fuel")
the second graph is correctly displayed... Can anyone help me with this issue? I have also tried to open the graph window through windows() before the first plot, but this doesn't work...
Thanks! Stefano

Answer 1

Your par(oma=c(3,3,0,0)) line should come before the first par(mar=...) call since it should be applied to the whole device region (i. e. you can't change the size of the outer margin if you already plotted some graphs).
scatterhist = function(x, y, xlab="", ylab=""){
zones=matrix(c(2,0,1,3), ncol=2, byrow=TRUE)
layout(zones, widths=c(4/5,1/5), heights=c(1/5,4/5))
par(oma=c(3,3,0,0))
xhist = hist(x, plot=F, breaks=10)
yhist = hist(y, plot=F, breaks=10)
top = max(c(xhist$counts, yhist$counts))
par(mar=c(3,3,1,1))
plot(x, y)
par(mar=c(0,3,1,1))
barplot(xhist$counts, axes=FALSE, ylim=c(0, top), space=0)
par(mar=c(3,0,1,1))
barplot(yhist$counts, axes=FALSE, xlim=c(0, top), space=0, horiz=TRUE)
mtext(xlab, side=1, line=1, outer=TRUE, adj=0,
at=.8 * (mean(x)-min(x))/(max(x)-min(x)))
mtext(ylab, side=2, line=1, outer=TRUE, adj=0,
at=.8 * (mean(y)-min(y))/(max(y)-min(y)))
}