Aspect ratio and limits

On Tuesday 19 April 2005 11:40, Barry Rowlingson wrote:

Marc Schwartz wrote:

# Set height value as you require
height <- 3
X11(width = aspect * height, height = height)
....
Does that get you what you need?

  I'm guessing that will work, but it just seems unsatisfactory,
since if I resize my graphics window I mess it up.

  If I set par(pty='s') I can have a square plot floating inside a
graphics window of any shape, I'd like to be able to plot something
specifying ylim and asp and get a rectangular plot with a fixed
aspect ratio floating around inside a resizable graphics device....

  The 'aspect' ratio of xyplot (lattice package) lets you specify the
aspect ratio of the plot (not relating to the data, ie aspect=1 draws
a square plot whatever the ratio of X and Y range). Try this:

  xy=data.frame(x=c(0,21),y=c(0,4))
  xyplot(y~x,data=xy,aspect=0.2)

  - now resize the graphics window and the plot keeps its ratio.
That's the effect I was hoping to get from base graphics.

  I could use lattice graphics but I'd have to work out the value of
'aspect' to get the 1:1 aspect ratio for my data. I'm not sure this
is trivial, since it may involve considering the various margins and
spacing around a plot.

Try (with a sufficiently recent version of R)

xyplot(y~x, data=xy, aspect="iso")

Is that what you want?