Better ways to create a rectangular mask by openCV

Question

Creating a mask in openCV

      /** result I want
          0 0 0 0 0 0 0 0
          0 0 0 0 0 0 0 0
          0 0 1 1 1 1 0 0
          0 0 1 1 1 1 0 0
                


        

Answer 1

sure, there's an easier way, use the roi operator:

cv::Mat mask = cv::Mat::zeros(8, 8, CV_8U); // all 0
mask(Rect(2,2,4,4)) = 1;

done!