GtkScrollbar base class for #GtkHScrollbar and GtkVScrollbar. The #GtkScrollbar widget is an abstract base class for #GtkHScrollbar and #GtkVScrollbar. It is not very useful in itself. The position of the thumb in a scrollbar is controlled by the scroll adjustments. See #GtkAdjustment for the fields in an adjustment - for #GtkScrollbar, the "value" field represents the position of the scrollbar, which must be between the "lower" field and "upper - page_size." The "page_size" field represents the size of the visible scrollable area. The "step_increment" and "page_increment" fields are used when the user asks to step down (using the small stepper arrows) or page down (using for example the PageDown key). #GtkHScrollbar a horizontal scrollbar. #GtkVScrollbar a vertical scrollbar. #GtkAdjustment connects scrollbars to the widget being scrolled. #GtkScrolledWindow convenient widget for setting up scrolling. The #GtkScrollbar struct does not contain any public data.