How to create an ROI (Region-Of-Interest or submat) from a contour?

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Given an image Mat, and a contour (which is a MatOfPoint) in it, how can I create a ROI (Region Of Interest)/submat?

I can see three interesting methods on docs of Mat,

Mat submat(int rowStart, int rowEnd, int colStart, int colEnd) Extracts a rectangular submatrix.

Mat submat(Range rowRange, Range colRange) Extracts a rectangular submatrix.

Mat submat(Rect roi) Extracts a rectangular submatrix.

• Is there a way to find out rowStart, rowEnd, colStart and colEnd from the contour?

or

• Is there a way to get rowRange and colRange from the contour?

or

• Can I make a Rect from the contour?