Adjuster - button-like interactors for incremental scrolling and zooming
Adjuster 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 and
Mover. Zoomers adjust the perspective's curwidth and
curheight members to suggest magnification. The user clicks on a
zoomer to magnify or reduce the contents of the interactor through its
perspective. The Enlarger zoomer subclass halves the perspective
values while the Reducer class doubles 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 perspective.
- 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 = NO_AUTOREPEAT)
- RightMover(Interactor*, int delay = NO_AUTOREPEAT)
- DownMover(Interactor*, int delay = NO_AUTOREPEAT)
- 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.