[R] Reverse axis in xyplot()

[Arni Magnusson]

Creating a plot with reverse Y axis is easy enough with traditional
graphics:
> x <- 1:3
> y <- 1:3
> plot(y~x, ylim=c(3,1))
  +-----------+
1 | o         |
  |           |
2 |     o     |
  |           |
3 |         o |
  +-----------+
    1   2   3

But xyplot doesn't grasp my idea:
> xyplot(y~x, ylim=c(3,1))
  +-----------+
3 |         o |
  |           |
2 |     o     |
  |           |
1 | o         |
  +-----------+
    1   2   3

Does anyone know how the reverse Y axis can be rendered with xyplot(),
perhaps using a customized panel function? I have tried post-processing
the trellis object elements, but with no luck. I have also tried the
xyplot(-y~x) workaround, but I don't know how to display the customized
labels.

Finally, I'm aware of the y<-ordered(y,rev(y)) workaround, but a solution
for the continuous case would be preferred.

Thanks in advance,
Arni