Convenience function that calls gtk_widget_queue_draw_region() on
the region created from the given coordinates.
The region here is specified in widget coordinates.
Widget coordinates are a bit odd; for historical reasons, they are
defined as widget->window coordinates for widgets that are not
GTK_NO_WINDOW widgets, and are relative to widget->allocation.x,
widget->allocation.y for widgets that are GTK_NO_WINDOW widgets.
Convenience function that calls gtk_widget_queue_draw_region() on the region created from the given coordinates. The region here is specified in widget coordinates. Widget coordinates are a bit odd; for historical reasons, they are defined as widget->window coordinates for widgets that are not GTK_NO_WINDOW widgets, and are relative to widget->allocation.x, widget->allocation.y for widgets that are GTK_NO_WINDOW widgets.