matplotlib/matplotlib — pull request #847 by neggert (2012-04-21 20:32:07+00:00)
Title: Add stacked kwarg to hist and implement stacked hists for step histtype

This PR addresses matplotlib/matplotlib#831. The main goal was to implement stacked histograms when using the `step` or `stepfilled` histtypes. Rather than add new histtypes as with the `barstacked` histtype, a new `stacked` kwarg was added. This kwarg behaves as expected for all four histtypes.

I've added an example showing what happens when `histtype="stepfilled", stacked=True`. Here is the output of the new example:

![stacked histogram example](http://cl.ly/G0pT/stackedhist.png)