int items_max; /* number of items to access */
int items_visible; /* number of visible items */
int item_position; /* actual item position */
+ int size_min; /* minimal scrollbar size */
int size_max; /* this is either width or height */
+ int size_max_cmp; /* needed for minimal scrollbar size */
int size; /* scrollbar size on screen */
int position; /* scrollbar position on screen */
int position_max; /* bottom/right scrollbar position */