NAME

       Panner - two-dimensional scrolling and zooming

SYNOPSIS

       #include <InterViews/panner.h>

DESCRIPTION

       A  panner  is  an  interactor  that  manipulates  the  perspective  of another interactor to provide two-
       dimensional scrolling and zooming.  A panner is composed of a slider and several adjusters, including two
       zoomers and four movers. The slider's position and size reflect the  current  origin,  size,  and  aspect
       ratio  in  the  interactor's  perspective.   Dragging  the  slider  around  with  the  mouse  changes the
       perspective's curx and cury members.

PUBLIC OPERATIONS

       Panner(Interactor*, int size = 0)
              Create a panner for the given interactor, optionally with the given width.  If the size  is  0,  a
              reasonable default size is used.  The panner's aspect ratio reflects that of the perspective.

       Slider(Interactor*)
       Slider::Handle(Event&)
       Slider::Reshape(Shape&)
       Slider::Update()
              A  slider  reflects  and  lets  the  user  specify  the  visible portion of the view.  A rectangle
              represents the visible area, while the area surrounding it represents the  total  area.   Clicking
              and  holding  down any mouse button on the rectangle allows you to drag it to a different position
              within the total area.  The perspective's current origin is shifted to reflect  the  new  position
              when  the  button is released.  Holding down the shift key while dragging the rectangle constrains
              its  motion  horizontally  or  vertically.   Clicking  outside  the  rectangle  moves  it  in  the
              corresponding  one  of eight directions; for example, clicking to the right of the rectangle moves
              it to the  right.   If  the  left  mouse  button  is  used,  the  movement  increment  equals  the
              perspective's  sx or sy member variables.  The middle mouse button increments by lx or ly, and the
              right mouse button centers the rectangle around the cursor.  The Reshape call sets  the  width  of
              the  slider  to  that  of  the  passed  Shape  and  calls Change on the parent interactor.  Update
              redisplays the slider to reflect a change in the interactor's perspective.

X DEFAULTS

       The ``syncScroll'' resource specifies  whether  the  slider  should  work  in  real-time  or  not.   When
       synchronized  scrolling  is  employed  the  interactor  scrolls  synchronously  as the slider is dragged;
       otherwise the slider's outline follows the mouse during dragging, and the  interactor  is  scrolled  only
       after the user stops dragging the slider.  Sliders will scroll synchronously if their syncScroll resource
       is set to ``on'' or ``true.''

SEE ALSO

       Adjuster(3I), Interactor(3I), Perspective(3I)

InterViews                                       15 January 1988                                      Panner(3I)