void center(int i) throws ScriptException {
		// from center (atom) or from zoomTo under conditions of not windowCentered()
		if (statementLength == 1) {
			viewer.setCenterBitSet(null, true);
			return;
		}

		if (statement[i].tok == Token.dollarsign) {
			// center $ id
			String axisID = objectNameParameter(i + 1);
			viewer.setNewRotationCenter(axisID);
			return;
		}

		if (statement[i].tok == Token.leftbrace) {
			// center { x y z }
			Point3f pt = getCoordinate(i, true);
			viewer.setNewRotationCenter(pt);
			return;
		}
		viewer.setCenterBitSet(expression(statement, i), true);
	}