Specific pano area always show on the stage

Help.
I want to make a flat pano whit a "special" area at the center (example 2000 x 2000 pixel and ad area at the center of 1000 x 1000), outside of the center area is like a "border".
Is possibile to set automatically (and dynamically) a zoom factor that show always (or after press a button) the entire center area at the maximun size possibile without cut it (also if I rotate the device)?
See the attachment for a better explanation.

Thanks!

Not exactly.
My area always cover the entire screen, I "simply" want that entire of the center area fit the screen and "cut" the rest of the pano (outside the center area).