Adjuster - button-like interactors for incremental scrolling and zooming
objects manipulate a perspective using a pushbutton-like
interface. Adjusters also provide an auto-repeat capability. Depressing and
holding down any mouse button on an adjuster for a specified time causes it to
repeatedly perform its operation. The auto-repeat terminates when the button
Predefined subclasses of Adjuster include Zoomer
Zoomers adjust the perspective's curwidth
to suggest magnification. The user clicks on a zoomer to magnify or reduce the
contents of the interactor through its perspective. The Enlarger
subclass halves the perspective values while the Reducer
them. Movers provide an incremental movement of the perspective in one of four
directions; left, right, down, or up. The user clicks on a mover to move the
- Adjuster(Interactor*, int = NO_AUTOREPEAT)
- Adjuster constructors take a pointer to the interactor
whose perspective will be adjusted and a delay (in tenths of a second)
after which auto-repeat will begin once the adjuster is ``pressed''.
- virtual void Highlight()
- virtual void UnHighlight()
- These functions define how the adjuster draws itself when
it is pressed. The adjuster is highlighted when it is pressed with any
mouse button and unhighlighted when the button is released. The default is
to invert the adjuster when highlighted.
- virtual void AdjustView(Event&)
- This function defines how the adjuster adjusts the
interactor's perspective. It is called after the adjuster is pressed and
released, or repeatedly during auto-repeat. Derived classes should
redefine this function to implement the desired behavior.
- Enlargers and reducers adjust an interactor's perspective
to enlarge and reduce the visible area by factors of one half and two,
respectively. This suggests to an interactor to enlarge or reduce its
contents. Auto-repeat is disabled on these adjusters.
- LeftMover(Interactor*, int delay =
- RightMover(Interactor*, int delay =
- DownMover(Interactor*, int delay =
- UpMover(Interactor*, int delay = NO_AUTOREPEAT)
- These subclasses of Mover adjust the current origin
of the interactor's perspective by an amount in the corresponding
direction. If the shift key is down while the mover is pressed, the amount
corresponds to the perspective's lx or ly member variables;
otherwise, the sx or sy values are used.