DI equal.axis

Function to configure a square plotting window.
 	
	
USAGE:
	equal.axis(x, y)


REQUIRED ARGUMENTS:

x
	range of x-values to be plotted

y
	range of y-values to be plotted

VALUE:
	A list object with components x and y, which are each
        two-component vectors giving the correct range for a 
        square plot window.

SEE ALSO:
	plot.network.setup

EXAMPLES:
# The function is currently defined as
function(x, y)
{
	pin <- par()$pin
	xr <- x[2] - x[1]
	yr <- y[2] - y[1]
	my <- mean(y)
	mx <- mean(x)
	r2 <- xr/(pin[1])
	r1 <- yr/(pin[2])
	if(r1 < r2) {
		yr <- (yr * r2)/r1
		y[1] <- my - yr/2
		y[2] <- my + yr/2
	}
	else {
		xr <- (xr * r1)/r2
		x[1] <- mx - xr/2
		x[2] <- mx + xr/2
	}
	return(list(x = x, y = y))
}