Modifies @orig to cover only the text after @split_index, and
returns a new item that covers the text before @split_index that
used to be in @orig. You can think of @split_index as the length of
the returned item. @split_index may not be 0, and it may not be
greater than or equal to the length of @orig (that is, there must
be at least one byte assigned to each item, you can't create a
zero-length item). @split_offset is the length of the first item in
chars, and must be provided because the text used to generate the
item isn't available, so pango_item_split() can't count the char
length of the split items itself.
Modifies @orig to cover only the text after @split_index, and returns a new item that covers the text before @split_index that used to be in @orig. You can think of @split_index as the length of the returned item. @split_index may not be 0, and it may not be greater than or equal to the length of @orig (that is, there must be at least one byte assigned to each item, you can't create a zero-length item). @split_offset is the length of the first item in chars, and must be provided because the text used to generate the item isn't available, so pango_item_split() can't count the char length of the split items itself.