Can be -1 for NUL-terminated string. This is useful for passing parts
of a larger string to a function without having to copy or modify the
string first.
Affected functions:
hb_tag_t hb_tag_from_string()
hb_direction_from_string()
hb_language_from_string()
hb_script_from_string()
Add compose() and decompose() unicode funcs. These implement
pair-wise canonical composition/decomposition.
The glib/icu implementations are lacking for now. We are adding
API for this to glib, but I cannot find any useful API in ICU.
May end of implementing these in-house.
Changed all unicode_funcs callback names to remove the "_get" part.
Eg, hb_unicode_get_script_func_t is now hb_unicode_script_func_t,
and hb_unicode_get_script() is hb_unicode_script() now.