pango:item-split (item index offset)

item -- a pango:item instance
index -- an integer with the byte index of the position to split item, relative to the start of the item
offset -- an integer with the number of chars between the start of item and index

New pango:item instance representing text before index.

Modifies item to cover only the text after index, and returns a new item that covers the text before index that used to be in item. You can think of index as the length of the returned item.

The index argument may not be 0, and it may not be greater than or equal to the length of item, that is, there must be at least one byte assigned to each item, you cannot create a zero-length item.

The offset argument is the length of the first item in chars, and must be provided because the text used to generate the item is not available, so the pango:item-split function cannot count the char length of the split items itself.