Pango::GravityHint defines how horizontal scripts should behave in a
That is, English excerpts in a vertical paragraph for example.
scripts will take their natural gravity based on the base gravity and the script. This is the default.
always use the base gravity set, regardless of the script.
for scripts not in their natural direction (eg. Latin in East gravity), choose per-script gravity such that every script respects the line progression. This means, Latin and Arabic will take opposite gravities and both flow top-to-bottom for example.
.g_type : UInt64
Returns the type id (GType) registered in GLib type system.