text that glyph_item corresponds to (glyph_item->item->offset is an offset from the start of text)
logical attributes for the item (the first logical attribute refers to the position before the first character in the item). array
amount of letter spacing to add in Pango units. May be negative, though too large negative values will give ugly results.
Adds spacing between the graphemes of glyph_item to give the effect of typographic letter spacing. Since 1.6