Question

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 cvGetSubRect call is?

I have the following, cvGetSubRect(some_cv_mat_pointer, another_cv_mat_pointer, some_cv_rect);

What is the equivalent to this in the C++ api?

Answer 1

You create an roi on the source image which gives you a new image – there is no actual pixel copying it all happens automatically

Mat image(.....)     // original image 
Rect roi(10, 20, 100, 50);     // shape of roi            
Mat image_roi = image(roi);    /// really a window into image, copy it if you need to change it

http://opencv.willowgarage.com/documentation/cpp/c++_cheatsheet.html