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)