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 per-
       spective's curx and cury members.

PUBLIC OPERATIONS

       Panner(Interactor*, int size = 0)
              Create a panner for the given  interactor,  option-
              ally  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  repre-
              sents  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 drag-
              ging the rectangle constrains its  motion  horizon-
              tally  or vertically.  Clicking outside the rectan-
              gle 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 per-
              spective.

X DEFAULTS

       The  ``syncScroll''  resource specifies whether the slider
       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)