"Prima::ScrollWidget" is a simple class that declares two pairs of properties,
delta and limit for vertical and horizontal axes, which define a
a virtual document. limit is the document dimension, and delta is
the current offset.
"Prima::ScrollWidget" is a descendant of "Prima::GroupScroller", and, as well as its
ascendant, provides same user navigation by two scrollbars. The scrollbars' "partial"
and "whole" properties are maintained if the document or widget extensions change.
deltas X, Y
Selects horizontal and vertical document offsets.
Selects horizontal document offset.
Selects vertical document offset.
limits X, Y
Selects horizontal and vertical document extensions.
Selects horizontal document extension.
Selects vertical document extension.
Scroll DX, DY
Called whenever the client area is to be scrolled. The default
action calls "Widget::scroll" .