[R] How to access the attributes of a ggplot?

[Tribo Laboy]

Hi,

I am having some hard time figuring how to access (and modify) the
properties of an object created by ggplot.

I found 'ggopts', but it only returns some of the properties.  Say I
want to get the x- and y-axis limits, the tickmark locations, legend
current position, the legend box and background color and set them to
new values.

Are these properties easily accessible (and modifiable) from the object?

Here is an example

library(ggplot2)
pobj <- ggplot(data = movies[1:300,], aes(x = year, y = length, size =
rating)) + geom_point() + opts(legend.position = c(0.2,0.9))

Regards,

TL