title: How can I extract plot axes' ranges for a ggplot2 object?
body: <p>I have an object from <code>ggplot2</code>, say <code>myPlot</code>, how can I identify the ranges for the x and y axes?</p>
  
  <p>It doesn't seem to be a simple multiple of the data values' range, because one can rescale plots, modify axes' ranges, and so on.  <code>findFn</code> (from <code>sos</code>) and Google don't seem to be turning up relevant results, other than how to set the axes' ranges.</p>