layout and arrange the figures on plot

## divide the device into two rows and two columns
## allocate figure 1 all of row 1
## allocate figure 2 the intersection of column 2 and row 2
# example 1
nf <- layout(mat = matrix(c(2,0,1,3),2,2,byrow=TRUE), widths = c(3,1), height = c(1,3), TRUE)
layout.show(nf)

## divide device into two rows and two columns
## allocate figure 1 and figure 2 as above
##-- Create a scatterplot with marginal histograms -----

x <- rnorm(50);
y <- runif(50);
xhist <- hist(x, plot=FALSE)
yhist <- hist(y, plot=FALSE)
top <- max(c(xhist$counts, yhist$counts))
xrange <- c(-1,1)
yrange <- c(0,1)

par(mar=c(3,3,1,1))
plot(x, y, xlim=xrange, ylim=yrange, xlab="", ylab="")
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)

###############################################
## example 2
## define the figure size on plot
mat <- matrix(c(1:6, 0, 7, 8), 3, 3, byrow = TRUE)
nf <- layout(mat, widths = c(3, 3, 3), height = c(3,3, 1), TRUE)
layout.show(nf)

###############################################
# example 3
mat <- matrix(c(1, 0, 0, 2:4, 5, 0, 0, 6:8, 0, 9, 10), 5, 3, byrow = TRUE)
nf <- layout(mat, widths = c(3, 2.5, 3), height = c(0.37, 3, 0.37, 3, 1.7), TRUE)
layout.show(nf)