函数 sws_getColorspaceDetails 

pub unsafe extern "C" fn sws_getColorspaceDetails(
    c: *mut SwsContext,
    inv_table: *mut *mut c_int,
    srcRange: *mut c_int,
    table: *mut *mut c_int,
    dstRange: *mut c_int,
    brightness: *mut c_int,
    contrast: *mut c_int,
    saturation: *mut c_int,
) -> c_int

@return A negative error code on error, non negative otherwise. If LIBSWSCALE_VERSION_MAJOR < 7, returns -1 if not supported.