Based on the script, base gravity, and hint, returns actual gravity
to use in laying out a single PangoItem.
If base_gravity is PANGO_GRAVITY_AUTO, it is first replaced with the
preferred gravity of script. To get the preferred gravity of a script,
pass PANGO_GRAVITY_AUTO and PANGO_GRAVITY_HINT_STRONG in.
Since 1.16
Based on the script, base gravity, and hint, returns actual gravity to use in laying out a single PangoItem. If base_gravity is PANGO_GRAVITY_AUTO, it is first replaced with the preferred gravity of script. To get the preferred gravity of a script, pass PANGO_GRAVITY_AUTO and PANGO_GRAVITY_HINT_STRONG in. Since 1.16