title: Displaying a histogram of image data
body: <p>I sometimes need to display a representation of <a href="http://en.wikipedia.org/wiki/Image_histogram" rel="noreferrer">image data in the form of a histogram</a>. I'm especially interested in ways to access the image data. I'm familiar with <code>JFreeChart</code>, which includes histogram support, but I'd consider other approaches.</p>