all geometric transform functions (except those which perform inverse warping operations) handle ROIs with the following sequence of operations:
ippiResizeSqrPixel does not look the filter function. For filter function, user need to handle the the border extension. ippiResizeSqrPixel will consider the border internally, and users does not need to extend these data.
I am checking with the function owner on why it needs interpolation in ippiGetResizeRect function, and hopefully provide more information here.