public float setRotateRight() {
        if (documentViewModel == null) {
            return -1;
        }
        float viewRotation = documentViewModel.getViewRotation();
        viewRotation -= ROTATION_FACTOR;
        if (viewRotation < -0)
            viewRotation += 360;
        documentViewModel.setViewRotation(viewRotation);
        documentViewScrollPane.revalidate();
        return viewRotation;
    }