title: How to plot Splines with ggplot2?
body: <p>I have some data that i want to make a histogram of.  However, I want to represent this histogram with line.  I have tried using the <code>freq_poly</code> of the <code>ggplot2</code>.  However, the line produced is pretty jagged.  I want to know if it is possible to use the <code>splines</code> with <code>ggplot2</code>, so that the line produced in <code>freq_poly</code> will be smoother.</p>
  
  <pre><code>d &lt;- rnorm( 1000 )
  h &lt;- hist( d, breaks="FD", plot=F )
  plot( spline( h$mids, h$counts ), type="l" )
  </code></pre>
  
  <p>This is what i want to accomplish.  But I want to do it using <code>ggplot2</code>.</p>