Here is an example of openvx code that scale image (nearest neighbour) with replicate borders and valid region.
For the input I have this image (valid region is {200, 200, 500, 300}):

Produced output (width is 2 * source width, height is source height) with the OpenVX-sample-impl library:

The question: why I see two images in the output? I suspected that output should contain stretched source valid region by the width.