cmd_curve4
m_storage.add(vertex_integer_type(x_ctrl1, y_ctrl1, vertex_integer_type::cmd_curve4));
m_storage.add(vertex_integer_type(x_ctrl2, y_ctrl2, vertex_integer_type::cmd_curve4));
m_storage.add(vertex_integer_type(x_to, y_to, vertex_integer_type::cmd_curve4));
case cmd_curve4: return path_cmd_curve4;