screenXLeft = screenX
screenXRight = screen.availWidth - screenX

screenYTop = screenY
screenYBottom = screen.availHeight - screenY - outerHeight

screenCenterX = screen.availWidth/2;
screenCenterX = screen.availHeight/2;

windowCenterX = outerWidth/2+screenX;
windowCenterX = outerHeight/2+0;

deltaCenterX = screenCenterX-windowCenterX