pango-item-split (orig split-index split-offset)

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

New pango-item instance representing text before split-index.

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 cannot 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 is not available, so the function pango-item-split cannot count the char length of the split items itself.