you would use basic pointer arithmetic to move the ROI in the source or destination.
So if you wanted to copy a source image of some size into a destination image starting at pixel (10,20), you’d do this:
[font=“Courier New”]Npp8u * pDst; // the destination image, assume that this has been allocated and filled with something
Npp8u * pDstOffset_10_20 = pDst + 20 * nDstStep + 10 * 4 /* four-channel */ * sizeof(Npp8u);
nppiCopy_8u_C4R(pSrc, nSrcStep, pDstOffset, nDstStep , oSizeROI);[/font]
Note, that oSizeROI must not exceed the source image’s size AND the destination image’s size reduced by the offset, i.e. destWidth - 10, destHeight - 20.
Hope that helps,