Min, Max, Pos, and Pagesize

The minimum and maximum determine the limits of the scrollbar. The pos sets the current position of the scrollbar which is within the limits double-inclusive. The pagesize is the primary grouping of the range of the scrollbar. This is the number of items in one page.

However, this paging system may not correspond to the actual paging system used by the programmer, especially with independent arrow operation set. For more information of the particular paging system, please consult the documentation additionally provided by the programmer.

Invert

This property determines the logical range of the scrollbar. With this property set, the roles of the Min and Max are interchanged. The Min should be set not lower but higher than the Max. In fact initially, the two values are interchanged. As discussed elsewhere, the MinArrow and MaxArrow behaves also differently.

Radix

The radix is the secondary grouping property of the scrollbar. If the coarse-tick division corresponding to the number of pages cannot be displayed in the scrollbar, the number of pages is continually divided by the radix until the resulting group number may be displayed by the scrollbar. If no solution can be obtained by using the radix, a dynradix is computed for the purpose. If still no solution is possible because the track area is not sufficient to display the trackers, the trackers and the ticks are not displayed. See also Ticks, TrackLevel and DynRadix for more information.

Indent

The indent determines the extent of scrollability of the whole range. With its value (which should be non-negative) set to zero (0), the range is fully scrollable. The larger the indent, the more limited the scrollability becomes by the value of the indent. In fact the value of the indent is usually, but not necessarily, set to the same value as the number of scrollable items which will fit in the the view or window, or viewsize. So when the total number of scrollable items is less than or equal to the indent, scrollability and the scrollbar elements are disabled. As a result, when the number of scrollable items is greater than the indent, the view or window is always full of items.

Again, the value of the indent is independently set. It may or may not be set relative to the view or the pagesize. However, these two values are the logical choice. Aside from the recommendation given above, the indent may also be set equal to the lower of the viewsize or pagesize. Unless used in conjunction with zooming or the like, do not set it to equal the pagesize (or any value) if the latter is greater than the viewsize; because doing so makes it impossible to view the last items equal to their difference.

Tracklevel

The continual division of the number of pages produces the tracklevels. The TrackLevelMax or the maximum tracklevel is the number of times the number of pages has been divided so that the scroll can display the coarse-tick divisions. As a result, the fine tracker can scan the positions in different track levels. TrackLevel 0 always moves the position by pages. TrackLevel 1 moves the position by radix number of pages. So if the radix is 10, the fine tracker moves the position 10 pages each fine-tick division. TrackLevel 2 moves the position 10*10 or 100 pages per fine-tick division. So the number of pages the finetracker can move per fine-tick division is the number of radix raised to the power of the tracklevel. Note that the radix may be replaced by the dynradix in some situations. See Radix and DynRadix for more information.

The tracklevel may be changed by right-clicking the arrows. See Arrows for more details.

Scrollbar Variables

These are always read-only variables. These are results in the calculation of the current scrollbar.

Coarse Granule

This is the number of coarse-tick divisions used by the scrollbar as a result of continually dividing the number of pages by the DynRadix. Each coarse-tick division moves the position by the DynRadix raised to the TrackLevel Max. See Scroll Info Tab for a discussion of how this is arrived at.

DynRadix

This is the actual radix used to calculate tracklevel operations. This is also the number of fine-tick divisions used by the scrollbar.

This value is at most equal to the Radix provided by the user, or programmer. The Radix is initially assigned to the DynRadix. If no solution is obtained to display the tick divisions, the DynRadix is binarily reduced until a solution is obtained, or until it becomes apparent that a solution cannot be obtained. In case of the latter, the trackers and ticks are not displayed.

Max

The TrackLevelMax is the value, which corresponds to the number of times the number of pages has been continually divided to obtain the Coarse Granule. This is the highest exponent, which can be used to move positions. The coarsetracker uses this value.