I have a question about OpenVG.

For our application, we need to change the background color runtime; we have 2 screens to manage: a white background when the Day visualization is selected or a black background when the Night visualization is selected.
My questions are:
- is there the possiblity to change the color of background runtime (and not only in the inizialization of the display)?
- what's OpenVG API I should use ?

We are using processor RZA1M for our application. For the graphics, we are using Altia Tool.

Thank you!