How to align ggplot title with window rather than plot grid?

Question

In ggplot2 version 0.9 the behaviour of the alignment of a plot title changed. Whereas in v0.8.9 the alignment was relative to the plot window, in v0.9 the alignment is relative to the plotting grid.

Now, whereas I mostly agree that this is desirable behaviour, I quite often have very long plot titles.

Question: Is there a way of aligning the plot title with the plot window rather than the plot grid?

I'm looking for an solution that does automatic alignment of the plot. In other words, manual alignment using hjust would not work for me (I run this on hundreds of plots for each project).

Any solution that used grid directly is also acceptable.

---

Some sample code and plot: (Notice how the title gets truncated at the right of window).

dat <- data.frame(
  text = c(
    "It made me feel very positive to brand X", 
    "It was clear and easy to understand",
    "I didn't like it al all"),
  value=runif(3)
)
library(ggplot2)
ggplot(dat, aes(text, value)) + 
  geom_bar(stat="identity") +
  coord_flip() +
  opts(title="Thinking about the ad that you've just seen, do you agree with the following statements? I agree that...") +
  theme_bw(16)

---

Answer 1

In ggplot2 0.9 you can easily change the layout.

p <- ggplot(dat, aes(text, value)) + 
  geom_bar(stat="identity") +
  coord_flip() +
  opts(title="Thinking about the ad that you've just seen,\ndo you agree with the following statements?\nI agree that...") +
  theme_bw(16)

gt <- ggplot_gtable(ggplot_build(p))
gt$layout[which(gt$layout$name == "title"), c("l", "r")] <- c(1, max(gt$layout$r))
grid::grid.draw(gt)

Perhaps, in the future version, ggplot2 will provide consistent interfaces for tweaking the layout.