Sets unset buffer segment properties based on buffer Unicode
contents. If buffer is not empty, it must have content type
#HB_BUFFER_CONTENT_TYPE_UNICODE.
If buffer script is not set (ie. is #HB_SCRIPT_INVALID), it
will be set to the Unicode script of the first character in
the buffer that has a script other than #HB_SCRIPT_COMMON,
#HB_SCRIPT_INHERITED, and #HB_SCRIPT_UNKNOWN.
Next, if buffer direction is not set (ie. is #HB_DIRECTION_INVALID),
it will be set to the natural horizontal direction of the
buffer script as returned by hb_script_get_horizontal_direction().
If hb_script_get_horizontal_direction() returns #HB_DIRECTION_INVALID,
then #HB_DIRECTION_LTR is used.
Finally, if buffer language is not set (ie. is #HB_LANGUAGE_INVALID),
it will be set to the process's default language as returned by
hb_language_get_default(). This may change in the future by
taking buffer script into consideration when choosing a language.
Note that hb_language_get_default() is NOT threadsafe the first time
it is called. See documentation for that function for details.
Sets unset buffer segment properties based on buffer Unicode contents. If buffer is not empty, it must have content type #HB_BUFFER_CONTENT_TYPE_UNICODE.
If buffer script is not set (ie. is #HB_SCRIPT_INVALID), it will be set to the Unicode script of the first character in the buffer that has a script other than #HB_SCRIPT_COMMON, #HB_SCRIPT_INHERITED, and #HB_SCRIPT_UNKNOWN.
Next, if buffer direction is not set (ie. is #HB_DIRECTION_INVALID), it will be set to the natural horizontal direction of the buffer script as returned by
hb_script_get_horizontal_direction(). Ifhb_script_get_horizontal_direction()returns #HB_DIRECTION_INVALID, then #HB_DIRECTION_LTR is used.Finally, if buffer language is not set (ie. is #HB_LANGUAGE_INVALID), it will be set to the process's default language as returned by
hb_language_get_default(). This may change in the future by taking buffer script into consideration when choosing a language. Note thathb_language_get_default()is NOT threadsafe the first time it is called. See documentation for that function for details.