title: Converting old Opencv code to the new C++ API, replacement for cvGetSubRect?
body: <p>I am converting some old OpenCV code using the C api to the new C++ API in OpenCV 2.3.  I am wondering what the method is to replace the <code>cvGetSubRect</code> call is?</p>
  
  <p>I have the following, <code>cvGetSubRect(some_cv_mat_pointer, another_cv_mat_pointer, some_cv_rect);</code></p>
  
  <p>What is the equivalent to this in the C++ api?</p>