is it possible to put an image inside another image and resize it always to a certain dimension?

I'm using opencv. The problem is this:

I have a window where I'm displaying an Image A. I have an image B coming from a videocamera, that has every time different dimensions/resolutions. Is it possible to display this image (like paste it) in anothe开发者_如何学Cr image but always inside a certain area, auto-resizing it if too small or too big to that precise area (a rectangle)?

Cheers

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Yes, if A has a ROI, then cvResize(B, A) will "paste" B into the ROI in A, scaling and stretching it to fit.