Volume 6A: Motif Programming Manual

an absolute number; clicking on either of the directional arrows changes the ScrollBar's value incrementally; clicking

in the scrolling region, but not on the slider itself changes the ScrollBar's value by page lengths. The value is

measured in units, not pixels.

The view length is the size of the viewable area (clip window), as measured in unit lengths. The vertical ScrollBar for

a Text widget that is displaying 15 lines of text would have a view length of 15. The horizontal ScrollBar's view

length would be the number of columns that the clip window can display.

The page length is measured in unit lengths and is usually one less than the view length. If the user scrolls the window

by a page increment, the first line from the old view is retained as the last line in the new view for visual reference

because otherwise, the user might lose her orientation.

10.3.1 Resources

the figure illustrates the relationship between the elements listed above and introduces the ScrollBar resources that

correspond to these values.

Conceptual relationship between a ScrollBar and the object it scrolls

The XmNincrement resource represents the number of units that the ScrollBar reports having scrolled when the user

clicks on its incremental arrows. The value for XmNincrement in the figure is 1 because each incremental scroll on

the vertical ScrollBar should scroll the text one line. Internally, the Text widget knows ...