bionic (3) Adjuster.3I.gz

NAME

       Adjuster - button-like interactors for incremental scrolling and zooming

SYNOPSIS

       #include <InterViews/adjuster.h>

DESCRIPTION

       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 is released.

       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.

PUBLIC OPERATIONS

       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.

PROTECTED OPERATIONS

       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.

DERIVED CLASSES

       Enlarger(Interactor*)
       Reducer(Interactor*)
              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.

SEE ALSO

       Interactor(3I), Perspective(3I)