[R] ggplot aspect ratio

[Ross Boylan]

Is there a way to control the aspect ratio of plots using ggplot?
Specifically, I'm using the formula=a~b argument to produce a grid of
plots, but the overall width of the result seems to vary for reasons
that are obscure to me.

This affects not only the appearance of the plots but the amount of
space available for the title (which seems to be right justified
relative to the right edge of the grid).

I've tried tweaking some parameters in the past, but they had no effect
that I could tell.

Perhaps related to that, my previous attempts to use abline to produce a
45 degree angle always produced a flat straight line.

There are also a bunch of other tweaks I want to make to get output
presentation ready.  Is it time to try ggplot2?  I found I could get
results very quickly with ggplot, but am not sure how much control it
gives me over the finer details.

Thanks.
-- 
Ross Boylan                                      wk:  (415) 514-8146
185 Berry St #5700                               ross at biostat.ucsf.edu
Dept of Epidemiology and Biostatistics           fax: (415) 514-8150
University of California, San Francisco
San Francisco, CA 94107-1739                     hm:  (415) 550-1062