Description The GtkAdjustment object represents a value which has an associated lower and upper bound, together with step and page increments, and a page size. It is used within several GTK+ widgets, including GtkSpinButton, GtkViewport, and GtkRange (which is a base class for GtkHScrollbar, GtkVScrollbar, GtkHScale, and GtkVScale). The GtkAdjustment object does not update the value itself. Instead it is left up to the owner of the GtkAdjustment to control the value. The owner of the GtkAdjustment typically calls the gtk_adjustment_value_changed() and gtk_adjustment_changed() functions after changing the value and its bounds. This results in the emission of the "value_changed" or "changed" signal respectively.