class MapViewport {

    public AffineTransform getScreenToWorld() {
        lock.readLock().lock();
        try {
            return screenToWorld == null ? null : new AffineTransform(screenToWorld);
        } finally {
            lock.readLock().unlock();
        }
    }

    public  MapViewport();
    public  MapViewport(boolean matchAspectRatio);
    public  MapViewport(ReferencedEnvelope bounds);
    public  MapViewport(ReferencedEnvelope bounds, boolean matchAspectRatio);
    public  MapViewport(MapViewport sourceViewport);

}