s.    *    * @return:    *   FreeType error code.  0~means success.    *    * @note:    *   Due to *PATENTS* covering subpixel rendering, this function doesn't    *   do anything except returning `FT_Err_Unimplemented_Feature' if the    *   configuration macro FT_CONFIG_OPTION_SUBPIXEL_RENDERING is not    *   defined in your build of the library, which should correspond to all    *   default builds of FreeType.    *    * 