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)