|
|
|
|
Now we have a brand new HarfBuzz buffer. Let's start filling it
with text! From HarfBuzz's perspective, a buffer is just a stream
of Unicode code points, but your input string is probably in one of
the standard Unicode character encodings (UTF-8, UTF-16, or
UTF-32). HarfBuzz provides convenience functions that accept
each of these encodings:
hb_buffer_add_utf8(),
hb_buffer_add_utf16(), and
hb_buffer_add_utf32(). Other than the
character encoding they accept, they function identically.
You can add UTF-8 text to a buffer by passing in the text array, the array's length, an offset into the array for the first character to add, and the length of the segment to add:
hb_buffer_add_utf8 (hb_buffer_t *buf,
const char *text,
int text_length,
unsigned int item_offset,
int item_length)
So, in practice, you can say:
hb_buffer_add_utf8(buf, text, strlen(text), 0, strlen(text));
This will append your new characters to
buf, not replace its existing
contents. Also, note that you can use -1 in
place of the first instance of strlen(text)
if your text array is NULL-terminated. Similarly, you can also use
-1 as the final argument want to add its full
contents.
Whatever start item_offset and
item_length you provide, HarfBuzz will also
attempt to grab the five characters before
the offset point and the five characters
after the designated end. These are the
before and after