public Mat(Mat m, Rect roi) - opencv4android Version 2.4.1 (Bug #2063)

• This constructor is not functioning properly.

• I have to swap the value of x and y, also width and height, of ROI, to make it work as it should, like this:
  

          int temp = roi.width;
          roi.width = roi.height;
          roi.height = temp;
  
          temp = roi.x;
          roi.x = roi.y;
          roi.y = temp;
  

• In Mat.java I found the constructor code :

    public Mat(Mat m, Rect roi)
    {

        nativeObj = n_Mat(m.nativeObj, roi.x, roi.x + roi.width, roi.y, roi.y + roi.height);

        return;
    }

Where the description for n_Mat is:

long org.opencv.core.Mat.n_Mat(long m_nativeObj, int rowRange_start, int rowRange_end, int
        colRange_start, int colRange_end)

I then tried to display image.rows (in c++) for a image with a width of 547 and a height of 289, the result is 289.

• So i reckon the constructor should actually be:

public Mat(Mat m, Rect roi)
    {

        nativeObj = n_Mat(m.nativeObj, roi.y, roi.y + roi.height, roi.x, roi.x + roi.width);

        return;
    }

BTW, I am using opencv4android version 2.4.1 (with eclipse).